STATE STANDARD OF THE UNION OF SSR
SAND FOR CONSTRUCTION WORKS
TEST METHODS
GOST 8735-88
(ST SEV 5446-85)
ST SEV 6317-88
STATE CONSTRUCTION COMMITTEE of the USSR
STATE STANDARD OF THE UNION OF SSR
|
SAND FOR CONSTRUCTION WORKS Methodstrials Sand for construction work. |
GOST 8735-88 (ST SEV 5446-85) |
Date of introduction 01.07.89
Failure to comply with the standard is punishable by law
This standard applies to sand used as aggregate for concrete in monolithic, precast concrete and reinforced concrete structures, as well as material for the corresponding types of construction work, and specifies test methods.
1. GENERAL PROVISIONS
1.1. The scope of the sand test methods specified in this standard is specified in.
1.2. Samples are weighed to an accuracy of 0.1% by weight, unless otherwise specified in the standard.
1.3. Samples or weighed portions of sand are dried to constant weight in a drying oven at a temperature of (105 ± 5)° From until the difference between the results of two weighings is no more than 0.1% of the mass. Each subsequent weighing is carried out after drying for at least 1 hour and cooling for at least 45 minutes.
1.4. The test results are calculated to the second decimal place, unless other instructions are given regarding the accuracy of the calculation.
1.5. The test result is taken as the arithmetic mean of the parallel determinations provided for the corresponding method.
Non-standardized measuring instruments must pass metrological certification in accordance with GOST 8.326-89.
(Modified edition. Amendment No. 2).
2. SAMPLING
2.1. During acceptance control at the manufacturing plant, spot samples are taken, from which, by mixing, one combined sample is obtained from the replaceable product of each technological line.
2.2. Sampling of point samples from technological lines transporting products to a warehouse or directly to vehicles is carried out by crossing the material flow on a belt conveyor or at points of a material flow difference using samplers or manually.
To check the quality of sand shipped directly to the open pit face, spot samples are taken during loading into vehicles.
The sampling interval for manual sampling can be increased if the manufacturer produces products of consistent quality. To establish the permissible sampling interval, the coefficient of variation of the values of the content of grains passing through a sieve with a mesh No. 016 and the content of dust and clay particles is determined on a quarterly basis. To determine the coefficient of variation of these indicators during the shift, every 15 minutes, spot samples with a mass of at least 2000 are taken. For each spot sample, the content of grains passing through a sieve with a mesh No. 016, and the content of dusty and clay particles are determined. Then the coefficients of variation of these indicators are calculated in accordance with GOST 8269.0-97.
Depending on the obtained maximum value of the coefficient of variation for the two determined indicators, the following intervals for taking spot samples during the shift are taken:
3 hours - with a coefficient of variation of the indicator up to 10%;
2 hours "" "" "15%.
(Modified edition, Amendment No. 2).
2.4. The mass of a spot sample with a sampling interval of 1 h should be at least 1500 g. four times.
If, when taking samples with a sampler, the mass of the spot sample turns out to be less than the specified one by more than 100 g, then it is necessary to increase the number of samples taken to ensure that the mass of the combined sample is at least 10,000 g.
To quarter the sample (after mixing it), the material cone is leveled and divided into four parts by mutually perpendicular lines passing through the center. Any two opposite quarters are sampled. By successive quartering, the sample is reduced by two, four times, etc. until a sample is obtained with a mass corresponding to p.
When conducting periodic tests, as well as during incoming control and when determining the properties of sand during geological exploration, the mass of the laboratory sample must ensure that all tests provided for by the standard are carried out. It is allowed to carry out several tests using one sample, if the determined properties of the sand do not change during the tests, and the mass of the laboratory sample must be at least twice the total mass required for the tests.
2.7. An analytical sample is taken from the laboratory sample for each test.
Samples are taken from the analytical sample in accordance with the test procedure.
2.8. For each laboratory sample intended for periodic testing in the central laboratory of the association or in a specialized laboratory, as well as for arbitration tests, a sampling report is drawn up, including the name and designation of the material, the place and date of sampling, the name of the manufacturer, the designation of the sample and the signature of the responsible for taking a sample of the face.
Selected samples are packed in such a way that the mass and properties of the materials do not change prior to testing.
Each sample is provided with two labels with the sample designation. One label is placed inside the package, the other in a prominent place on the package.
During transportation, the packaging must be protected from mechanical damage and moisture.
2.9. To check the quality of sand extracted and laid by hydromechanization, the reclamation map is divided in plan along the length (along the alluvium map) into three parts.
Point samples are taken from each part from at least five different locations (in plan). To take a spot sample, a hole is dug with a depth of 0.2-0.4 m. A sample of sand is taken from the hole with a scoop, moving it from bottom to top along the wall of the hole.
From the spot samples by mixing, a combined sample is obtained, which is reduced to obtain a laboratory sample according to p.
The quality of the sand is assessed separately for each part of the reclamation map according to the results of testing a sample taken from it.
2.10. In the arbitration check of the quality of sand in warehouses, spot samples are taken with a scoop in places located evenly over the entire surface of the warehouse, from the bottom of dug holes with a depth of 0.2-0.4 m. The holes should be staggered. The distance between the holes should not exceed 10 m. The laboratory sample is prepared according to p.
Based on the results of sieving, calculate: the partial residue on each sieve ( a i) as a percentage according to the formula
(3)
where t i - the mass of the residue on a given sieve, g;
T -weight of the sieved sample, g;
total residue on each sieve ( A i) as a percentage according to the formula
(4)
where a 2,5 , a 1,25 , a i- partial residues on the respective sieves;
sand size modulus ( M j) without grains larger than 5 mm according to the formula
(5)
where A 2,5 , A 1,25 ,A 063 , A 0315 , A 016 - complete residues on a sieve with round holes 2.5 mm in diameter and on sieves with meshes No. 1.25; 063; 0315, 016,%.
The result of determining the grain size composition of sand is drawn up in accordance with table. or depicted graphically in the form of a sieving curve in accordance with fig. ...
Sieving curve
Residues,% by weight, on sieves
Pass through a sieve with mesh No. 016 (014),
% by weight
0,16
(0,14)
a 016(014)
a 016(014)
A 016(014)
Drying cabinet.
Sieves with mesh No. 1.25 in accordance with GOST 6613-86
The needle is steel.
4.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes with a diameter of 5 mm, take from it at least 100 g of sand, dried to constant weight and scattered on sieves with holes with a diameter of 2.5 mm and a mesh No. 1.25. From the obtained sand fractions, weighed samples are taken with a mass:
5.0 g - fraction of St. 2.5 to 5 mm;
1.0 g - fractions from 1.25 to 2.5 mm
Each weighed amount of sand is poured into a thin layer on glass or metal sheet and moistened with a pipette. Clumps of clay differing in viscosity are isolated from the sample with a steel needle. from sand grains, using a magnifying glass if necessary. The sand grains remaining after the separation of lumps are dried to constant weight and weighed.
4.4.Processing of results
(6)
(7)
where m 1 , m 2 - the weights of the sample of sand of the fraction, respectively, from 2.5 to 5 mm and from 1.25 to 2.5 mm before the release of clay, g;
T 1 ;m 3 - the mass of sand grains, fraction, respectively, from 2.5 to 5 mm and from 1.25 to 2.5 mm after the separation of clay, g.
(8)
where a 2,5 , a 1.25 - partial residues in percent by weight on sieves with openings of 2.5 and 1.25 mm, calculated according to p.
5. DETERMINATION OF THE CONTENT OF DUST AND CLAY PARTICLES
5.1. Elimination method
5.1.1. The essence of the method
Drying cabinet.
A cylindrical bucket with a height of at least 300 mm with a siphon or a vessel for eluting sand (drawing).
Stopwatch in accordance with GOST 5072-79.
(Modified edition, Amendment No. 2).
5.1.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter, the sand that has passed through the sieve is dried to constant weight and a sample of 1000 g is taken from it.
5.1.4. Testing
A weighed amount of sand is placed in a cylindrical bucket and filled with water so that the height of the water layer above the sand is about 200 mm. The sand filled with water is kept for 2 hours, stirring it several times, and thoroughly washed from the clay particles adhering to the grains.
Thereafter, the contents of the bucket are vigorously mixed again and left alone for 2 minutes. After 2 minutes, drain the suspension obtained during washing with a siphon, leaving its layer above the sand with a height of at least 30 mm. Then the sand is again poured with water to the above level. Washing the sand in this sequence is repeated until the water after washing remains clear.
When using an elutriation vessel, the test is carried out in the same sequence. In this case, water is poured into the vessel up to the upper drain hole, and the suspension is poured through the two lower holes.
After elutriation, the washed sample is dried to constant weight T 1 .
5.1.5. Processing of results
(9)
where T - weight of the dried sample before elutriation, g;
m 1 is the mass of the dried sample after elutriation, g.
Exhaustion vessel
The bucket is cylindrical with two marks (belts) on the inner wall, corresponding to a capacity of 5 and 10 liters.
The bucket is cylindrical without marks.
Drying cabinet.
Sieves with mesh No. 063 and 016 in accordance with GOST 6613-86.
Metal cylinders with a capacity of 1000 ml with a viewing window (2 pcs.).
Pipette, metal, volumetric with a capacity of 50 ml (drawing).
Funnel with a diameter of 150 mm.
Stopwatch in accordance with GOST 5072-79
A cup or glass for evaporation in accordance with GOST 9147-80.
(Modified edition, Amendment No. 2).
5.2.3. Testing
A sample of sand weighing about 1000 g in a state of natural moisture is weighed, placed in a bucket (without a label) and filled with 4.5 liters of water. In addition, about 500 ml of water is prepared for subsequent rinsing of the bucket.
The sand filled with water is kept for 2 hours, stirring it several times, and thoroughly washed from the clay particles adhering to the grains. Then the contents of the bucket are poured carefully onto two sieves: the upper one with mesh No. 063 and the lower one with mesh No. 016, placed on a bucket with marks.
The suspensions are allowed to settle and the clarified water is carefully poured into the first bucket. The sand is washed again with the drained water on sieves over the second bucket (with marks). After that, the first bucket is rinsed with the water left and this water is drained into the second bucket. At the same time, such an amount of the left water is used so that the level of the suspension in the latter reaches exactly the 5 l mark; if the remaining water is not enough for this, the volume of the suspension is brought to 5 liters by adding additional water.
After that, the suspension is thoroughly mixed in a bucket and immediately filled with it using a funnel, alternately two metal cylinders with a capacity of 1000 ml, while continuing to stir the suspension. The slurry level in each cylinder must match the mark on the sight glass.
The suspension in each cylinder is stirred with a glass or metal rod or the cylinder is overturned several times, closing it with a lid for better mixing.
After the end of stirring, leave the cylinder at rest for 1.5 minutes. 5-10 s before the end of exposure, a graduated pipette with a tube closed with a finger is lowered into the cylinder so that the support cap rests on the top of the cylinder wall, while the bottom of the pipette will be at the level of suspension withdrawal - 190 mm from the surface. After the specified time (5-10 s), open the pipette tube and after filling it again close the tube with a finger, remove the pipette from the cylinder and, opening the tube, pour the contents of the pipette into a pre-weighed cup or glass. The filling of the pipette is controlled by the change in the level of the suspension in the viewing window.
Metal cylinder and volumetric pipette
5.3. Wet sieving method
The test is carried out in accordance with GOST 8269.0-97, using a sample of sand weighing 1000 g and a sieve with a mesh No. 0315 and 005.
(Modified edition, Amendment No. 2).
5.4. Photoelectric method
The method is based on comparing the degree of transparency of pure water and a suspension obtained by washing the sand.
The test is carried out in accordance with GOST 8269.0-97, using a sample of sand weighing 1000 g.
(Modified edition, Amendment No. 2).
5.5. The content of dust and clay particles can be determined by one of the above methods, depending on the availability of equipment. In this case, the elutriation method is allowed to be used until 01/01/95.
6. DETERMINATION OF THE PRESENCE OF ORGANIC IMPURITIES
6.1. The essence of the method
The presence of organic impurities (humic substances) is determined by comparing the color of the alkaline solution above the sample of sand with the color of the standard.
Photocolorimeter FEK-56M or spectrophotometer SF-4, or other similar devices.
Glass cylinders with a capacity of 250 ml made of transparent colorless glass (inner diameter 36-40 mm) in accordance with GOST 1770-74.
Bath water.
Sodium hydroxide (sodium hydroxide) in accordance with GOST 4328-77, 3% solution.
Tannin, 2% solution in 1% ethanol.
(Modified edition, Amendment No. 2).
6.3. Test preparation
A sample of about 250 g is taken from an analytical sample of sand in a state of natural moisture.
Prepare a standard solution by dissolving 2.5 ml of 2% tannin solution in 97.5 ml of 3% sodium hydroxide solution. The prepared solution is stirred and left for 24 hours.
The optical density of the tannin solution, determined on a photocolorimeter or spectrophotometer in the wavelength range of 450-500 nm, should be 0.60-0.68.
6.4. Testing
The measuring cylinder is filled with sand to a level of 130 ml and it is filled with a 3% sodium hydroxide solution to a level of 200 ml. The contents of the cylinder are stirred and left for 24 hours, stirring is repeated 4 hours after the first stirring. Then compare the color of the liquid over the sample with the color of the standard solution or glass, the color of which is identical to the color of the standard solution.
Sand is suitable for use in concrete or mortar if the liquid above the sample is colorless or is much weaker than the standard solution.
When the color of the liquid is slightly lighter than the standard solution, the contents of the vessel are heated for 2-3 hours in a water bath at a temperature of 60-70 ° C and the color of the liquid above the sample is compared with the color of the standard solution.
When the color of the liquid is the same or darker than the color of the standard solution, it is necessary to test the aggregate in concrete or solutions in specialized laboratories.
7. DETERMINATION OF MINERAL AND PETROGRAPHIC COMPOSITION
7.1. The essence of the method
A set of sieves with meshes No. 1.25; 063; 0315 and 016 in accordance with GOST 6613-86 and with round holes with diameters of 5 and 2.5 mm.
Drying cabinet.
Binocular microscope with magnification from 10 to 50 C , polarizing microscope with magnification up to 1350 C .
Mineralogical magnifier in accordance with GOST 25706-83.
A set of reagents.
The needle is steel.
(Modified edition, Amendment No. 2).
7.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter, at least 500 g of sand is taken from the sieved part of the sample.
The sand is washed, dried to constant weight, scattered on a set of sieves with holes 2.5 mm in diameter and mesh No. 1.25; 063; 0315; 016 and take a sample with a mass of at least:
25.0 g - for sand with grain size. 2.5 to 5.0 mm;
5.0 g "" "" "St. 1.25 to 2.5 mm;
1.0 g "" "" "St. 0.63 to 1.25 mm;
0.1 g "" "" "St. 0.315 to 0.63 mm;
0.01 g "" "" "from 0.16 to 0.315 mm.
7.4. Testing
Each sample is poured into a thin layer on glass or paper and viewed with a binocular microscope or magnifying glass.
Sand grains, represented by fragments of the corresponding rocks and minerals, are divided with a thin needle into groups according to the types of rocks and types of minerals.
If necessary, the determination of rocks and minerals is clarified using chemical reagents (hydrochloric acid solution, etc.), as well as by analysis in immersion liquids using a polarizing microscope.
In the grains of sand, represented by fragments of minerals, the content of quartz, feldspar, dark-colored minerals, calcite, etc. is determined.
Sand grains, represented by rock debris, are divided according to genetic types in accordance with table. ...
table 2
In addition, grains of rocks and minerals attributed to harmful impurities are isolated in the sand.
These rocks and minerals include: containing amorphous varieties of silicon dioxide (chalcedony, opal, flint, etc.); sulfur; sulfides (pyrite, marcasite, pyrrhotite, etc.); sulfates (gypsum, anhydrite, etc.); layered silicates (micas, hydromicas, chlorites, etc.); iron oxides and hydroxides (magnetite, goethite, etc.); apatite; nepheline; phosphorite; halide compounds (halite, sylvin, etc.); zeolites; asbestos; graphite; coal; oil shale.
In the presence of minerals containing sulfur, the amount of sulfate and sulfide compounds in terms of SO 3 determined by p.
.The same weighed portions of sand are used to determine the shape and nature of the surface of sand grains in accordance with table. ...
Table 3
7.5. Processing of results
For each type of identified rocks and minerals, the number of grains is counted and their content is determined ( X) as a percentage in the sample according to the formula
(14)
where n - the number of grains of a given rock or mineral;
N -the total number of grains in the test sample.
8. DETERMINATION OF TRUE DENSITY
8.1. Pycnometric method
8.1.1. The essence of the method
True density is determined by measuring the mass per unit volume of dried sand grains.
Piconometer with a capacity of 100 ml in accordance with GOST 22524-77.
Desiccator in accordance with GOST 25336-82.
Drying cabinet.
Sand bath or water bath.
Distilled water in accordance with GOST 6709-72.
GOST 450-77.
(Modified edition, Amendment No. 2).
8.1.3. Test preparation
A sample of about 30 g is taken from an analytical sample of sand, sieved through a sieve with holes 5 mm in diameter, dried to constant weight and cooled to room temperature in a desiccator over concentrated sulfuric acid or anhydrous calcium chloride. The dried sand is mixed and divided into two parts.
8.1.4. Testing
Each part of the sample is poured into a clean, dried and previously weighed pycnometer, after which it is weighed together with the sand. Then distilled water is poured into the pycnometer in such an amount that the pycnometer is filled to about 2/3 of its volume, the contents are mixed and placed in a slightly inclined position on a sand bath or water bath. The contents of the pycnometer are boiled for 15-20 minutes to remove air bubbles; air bubbles can also be removed by keeping the pycnometer under vacuum in a desiccator.
After removing the air, the pycnometer is wiped off, cooled to room temperature, added to the mark with distilled water and weighed. After that, the pycnometer is freed from the contents, washed, filled to the mark with distilled water and weighed again. All weighings are carried out with an error of up to 0.01 g.
8.1.5. Processing of results
The true density of the sand (r) in g / cm 3 is calculated by the formula
Le Chatelier device (fig.).
Weighing glass or porcelain cup in accordance with GOST 9147-80.
Desiccator in accordance with GOST 25336-82.
Drying cabinet.
Sieve with round holes 5 mm.
Sulfuric acid in accordance with GOST 2184-77.
Calcium chloride (calcium chloride) in accordance with GOST 450-77.
(Modified edition, Amendment No. 2).
Le Chatelier device
Sieve with round holes 5 mm in diameter.
(Modified edition, Amendment No. 2).
9.1.3. Test preparation
9.1.3.1. When determining the bulk density in a standard unconsolidated state during the incoming control, tests are carried out in a measuring cylindrical vessel with a capacity of 1 liter, using about 5 kg of sand, dried to constant weight and sifted through a sieve with round holes 5 mm in diameter.
9.1.3.2. When determining the bulk density of sand in a batch, to convert the amount of supplied sand from mass units to volumetric units at. acceptance control tests are carried out in a measuring cylindrical vessel with a capacity of 10 liters. The sand is tested in a state of natural moisture without sieving through a sieve with holes of 5 mm diameter.
9.1.4. Testing
9.1.4.1. When determining the bulk density of sand in a standard uncompacted state, sand is poured with a scoop into a pre-weighed measuring cylinder from a height of 10 cm from the top edge until a cone is formed above the top of the cylinder. The cone without compaction of sand is removed flush with the edges of the vessel with a metal ruler, after which the vessel with sand is weighed.
9.1.4.2. When determining the bulk density of sand in a batch, to convert the amount of supplied sand from mass units to volume units, sand is poured with a scoop into a pre-weighed measuring cylinder from a height of 100 cm from the upper edge of the cylinder until a cone is formed above the top of the cylinder. The cone without compaction of sand is removed flush with the edges of the vessel with a metal ruler, after which the vessel with sand is weighed.
Bulk density of sand (r n ) in kg / m 3 is calculated by the formula
(18)
where T - weight of the measuring vessel, kg;
T 1 - mass of a measuring vessel with sand, kg;
V -vessel volume, m 3.
The determination of the bulk density of the sand is carried out twice, each time taking a new portion of the sand.
Note. The bulk density of the sand and gravel mixture is determined according to GOST 8269-87.
9.2. Definition of voidness
The voidness (volume of intergranular voids) of sand in a standard unconsolidated state is determined based on the values of the true density and bulk density of the sand, previously established in paragraphs. and .
The voidness of the sand (V m.p ) as a percentage by volume is calculated by the formula
(19)
where r - true density of sand, g / cm 3;
r n - bulk density of sand, kg / m 3.
10. DETERMINATION OF MOISTURE
10.1. The essence of the method
The moisture content is determined by comparing the mass of the sand in the state of natural moisture and after drying.
Drying cabinet.
Baking tray.
(Modified edition, Amendment No. 2).
10.3. Testing
A sample weighing 1000 g of sand is poured into a baking sheet and immediately weighed, and then dried in the same baking sheet to constant weight.
10.4. Processing of results
Sand moisture (W) as a percentage is calculated by the formula
(20)
where T - the weight of the sample in a state of natural moisture;
T 1 - dry sample weight, g.
11. DETERMINATION OF REACTIVITY
The test is carried out in accordance with GOST 8269-87, using a sample of sand weighing at least 250 g.
12. DETERMINATION OF THE CONTENT OF SULPHATE AND SULFIDE COMPOUNDS
12.1. To determine the content of harmful sulfur-containing impurities in the sand, the total sulfur content is found, then the sulfate sulfur content and the sulfide sulfur content is calculated from their difference.
If the sand contains only sulfate compounds, the total sulfur content is not determined.
12.2. Determination of total sulfur content
12.2.1. Weight method
12.2.1.1. The essence of the method
The gravimetric method is based on the decomposition of a sample with a mixture of nitric and hydrochloric acids, followed by the precipitation of sulfur in the form of barium sulfate and the determination of the mass of the latter.
A muffle furnace providing a heating temperature of 900 ° C.
Porcelain cups with a diameter of 15 cm in accordance with GOST 9147-80.
Glass glasses with a capacity of 100, 200 300 400 ml in accordance with GOST 23932-90.
Porcelain crucibles in accordance with GOST 9147-80.
Desiccator in accordance with GOST 25336-82.
Bath water.
Calcium chloride (calcium chloride) in accordance with GOST 450-77, calcined at a temperature of 700-800 ° C.
Ash paper filters according to TU 6-09-1706-82.
Nitric acid in accordance with GOST 4461-77.
Hydrochloric acid in accordance with GOST 3118-77.
Ammonia water according to GOST 3760-79, 10% solution.
Barium chloride (barium chloride) according to GOST 4108-72, 10% solution.
Methyl orange according to TU 6-09-5169-84, 0.1% solution.
Silver nitrate (silver nitrate) in accordance with GOST 1277-75, 1% solution.
Woven wire sieves with square meshes No. 005 and 0071 in accordance with GOST 6613-86.
(Modified edition, Amendment No. 2).
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter and 100 g of sand is taken from the sieved part, which is crushed to a particle size passing through a sieve with a mesh No. 016, a sample weighing 50 g is taken from the resulting sand. The sample is crushed again to particle size passing through a sieve No. 0071.
The crushed sand is dried to constant weight, placed in a weighing bottle, stored in a desiccator over calcined calcium chloride, and weighed portions are taken from it for analysis ( T) weighing 0.5-2 g.
A sample, weighed with an accuracy of 0.0002 g, is placed in a glass beaker with a capacity of 200 ml or a porcelain cup, moistened with a few drops of distilled water, add 30 ml of nitric acid, cover with glass and leave for 10-15 minutes. After the end of the reaction, add 10 ml of hydrochloric acid, stir with a glass rod, cover with glass and put a glass or a cup in a water bath. In 20-30 minutes after the cessation of the evolution of brown vapors of nitrogen oxides, the glass is removed and the contents of the glass or cup are evaporated to dryness. After cooling, the residue is moistened with 5-7 ml of hydrochloric acid and again evaporated to dryness. The operation is repeated 2-3 times, add 50 ml of hot water and boil until the salts are completely dissolved.
To precipitate the elements of the group of sesquioxides, 2-3 drops of methyl orange indicator are added to the solution and the ammonia solution is added until the color of the solution changes from red to yellow and the smell of ammonia appears. After 10 minutes, the coagulated sesquioxides precipitate is filtered through a "red ribbon" filter into a beaker with a capacity of 300-400 ml. The precipitate is washed with warm water with the addition of a few drops of ammonia solution. Hydrochloric acid is added to the filtrate until the color of the solution turns pink, and another 2.5 ml of acid is added.
The filtrate is diluted with water to a volume of 200-250 ml, heated to boiling, 10 ml of a hot barium chloride solution is poured into it at one time, stirred, the solution is boiled for 5-10 minutes and left for at least 2 hours. The precipitate is filtered through a dense filter " blue ribbon ”and washed 10 times with small portions of cold water to remove chloride ions.
After cooling in a desiccator, the crucible with the sediment is weighed. Calcination is repeated until constant weight is obtained. To determine the sulfur content in the reagents used for the analysis, a "blind experiment" is carried out in parallel with the analysis. The amount of barium sulfate found by "blind experience" T 2, subtracted from the mass of barium sulfate T 1 obtained by analyzing the sample.
Note. The expression "blind experience" means that the test is carried out in the absence of the test object, using the same reagents and observing all the conditions of the experiment.
The total sulfate sulfur content ( NS 1) as a percentage based on SO 3 calculated by the formula
Permissible discrepancy, abs. %
St. 0.5 to 1.0
12.2.2. Iodometric titration method
12.2.2.1. The essence of the method
The method is based on the combustion of a sample in a flow of carbon dioxide at a temperature of 1300-1350 ° C, the absorption of the released SO 2 iodine solution and titration with sodium thiosulfate solution of excess iodine, which did not enter into the reaction with the formed sulfurous acid.
).Sodium thiosulfate according to GOST 27068-86, 0.005 N. solution.
Sodium carbonate (sodium carbonate) in accordance with GOST 83-79.
Potassium dichromate (potassium dichromate) in accordance with GOST 4220-75, fixed channel.
Soluble starch according to GOST 10163-76, 1.0% solution.
Iodine in accordance with GOST 4159-79, 0.005 N solution.
Potassium iodide (potassium iodide) in accordance with GOST 4232-74.
Sulfuric acid in accordance with GOST 4204-77, 0.1 n solution.
Analytical balance, measurement error 0.0002 g.
To prepare a solution of sodium thiosulfate dissolve 1.25 g Na 2 S 2 O 3 · 5 H 2 O in 1 liter of freshly boiled distilled water and add 0.1 g of sodium carbonate. The solution is stirred and left for 10-12 days, after which its titer is determined by 0.01 N potassium dichromate solution prepared from the fixed channel.
To 10 ml of a 0.01 n solution of potassium dichromate add 50 ml of a 0.1 n solution of sulfuric acid, 2 g of dry potassium iodide and titrate with the prepared sodium thiosulfate solution until a straw-yellow color. Add a few drops of a 1% starch solution (the solution turns blue) and titrate until the solution becomes discolored. Correction factor to the titer of 0.005 N sodium thiosulfate solution determined by the formula
(22)
where - the normality of the potassium dichromate solution;
10 - the volume of 0.01 n potassium dichromate solution taken for titration, ml;
V -volume of 0.005 n sodium thiosulfate solution consumed for titration of 10 ml of 0.01 n potassium dichromate solution, ml;
Normality of sodium thiosulfate solution.
The titer is checked at least once every 10 days.
Store the sodium thiosulfate solution in dark bottles.
To prepare a solution of iodine, 0.63 g of crystalline iodine and 10 g of potassium iodide are dissolved in 15 ml of distilled water. The solution is transferred to a 1 L volumetric flask with a well-ground stopper, filled up to the mark with water, mixed and stored in the dark.
The titer of the prepared iodine solution is established using the titrated solution of sodium thiosulfate prepared by the method described above (item).
10 ml of 0.005 N iodine solution is titrated with 0.005 N sodium thiosulfate solution in the presence of starch.
The correction factor to the titer of 0.005 N iodine solution () is determined by the formula
(23)
where - volume of 0.005 n sodium thiosulfate solution consumed for titration of iodine solution, ml;
Correction factor 0.005 N sodium thiosulfate solution;
- the normality of the iodine solution;
10 - the amount of iodine solution taken for titration, ml.
12.2.2.5. Test preparation
Test portions are prepared in accordance with clause 12.1.1.3, while the weight of the portions is taken equal to 0.1-1.0 g.
Before starting work, the furnace is heated to a temperature of 1300 ° C and the tightness of the installation is checked. To do this, close the tap in front of the absorption vessel and release carbon dioxide. The cessation of the passage of gas bubbles through the flushing bottle indicates the tightness of the installation.
Determine the coefficient TO, establishing the ratio between the concentrations of iodine solution and sodium thiosulfate. Carbon dioxide is passed through the installation for 3-5 minutes, the absorption vessel is filled 2/3 with water. From the burette, pour 10 ml of a titrated iodine solution, add 5 ml of a 1.0% starch solution and titrate with a sodium thiosulfate solution until the solution becomes discolored. The ratio of the concentration of solutions of iodine and sodium thiosulfate TO take equal to the average of the three definitions. Concentration ratio ratio TO under laboratory conditions, determined daily before testing.
12.2.2.6. Testing
The weighed portion, weighed to the nearest 0.0002 g, is placed in a pre-calcined boat. 250-300 ml of distilled water is poured into the absorption vessel, the volume of iodine solution measured by the burette, 5 ml of starch solution is added and stirred with a stream of carbon dioxide.
Installation diagram for the determination of sulfur content
For the analysis, equipment is used, reagents in the solutions specified in clause, while using hydrochloric acid according to GOST 3118-77, solution 1: 3 (one volume part of concentrated hydrochloric acid and three volume parts of water).
12.3.3. Test preparation
The test portion is prepared according to clause 12.1.1.3, while the weight of the sample is taken equal to 1 g.
12.3.4. Testing
Hinge T placed in a glass with a capacity of 100-150 ml, covered with glass and add 40-50 ml of hydrochloric acid. After the release of gas bubbles has ceased, the glass is placed on the hotplate and kept at a low boil for 10-15 minutes. Sesquioxides are precipitated by adding 2-3 drops of methyl orange indicator and adding ammonia solution until the indicator color changes from red to yellow and the smell of ammonia appears. After 10 minutes, the precipitate is filtered off. The precipitate is washed with warm water with the addition of a few drops of ammonia solution.
The filtrate is neutralized with hydrochloric acid until the color of the solution turns pink and another 2.5 ml of acid is added. The solution is heated to a boil and 10 ml of hot barium chloride solution is added at one time, stirred, the solution is boiled for 5-10 minutes and left for at least 2 hours. The precipitate is filtered through a dense filter "blue ribbon" and washed 10 times with small portions of cold water before removal of chloride ions.
The completeness of the removal of chloride ions is checked by the reaction with silver nitrate: a few drops of the filtrate are placed on glass and a drop of a 1% solution of silver nitrate is added. The absence of the formation of a white precipitate indicates the completeness of the removal of chloride ions.
A precipitate with a filter is placed in a porcelain crucible, previously calcined to constant weight at a temperature of 800-850 ° C, dried, incinerated, avoiding ignition of the filter, and calcined in an open crucible until the filter is completely burned out, and then at a temperature of 800-850 ° C in within 30-40 minutes.
After cooling in a desiccator, the crucible with the sediment is weighed. Calcination is repeated until constant weight is obtained.
In parallel with the analysis, a "deaf experience" is carried out (see note to p.). Barium sulfate amount T 2 found by "deaf experience" is subtracted from the mass of barium sulfate T 1 obtained by analyzing the sample.
12.3.5. Processing of results
Acceptable discrepancies between the results of two parallel analyzes are taken according to cl.
12.4. Determination of sulfide sulfur content
(27)
where NS - total sulfur content in terms of SO 3,%;
X 1 - the content of sulphate sulfur in terms of SO 3,%.
13. DETERMINATION OF FROST RESISTANCE OF SAND FROM CRUSHING DEPOSITS
13.1. The essence of the method
The frost resistance of sand is determined by the loss of mass during successive freezing and thawing.
Freezer chamber.
Drying cabinet.
Sieves with meshes No. 1.25; 016 in accordance with GOST 6613-86 and with round holes 5 mm in diameter.
A vessel for thawing samples.
Cloth bags made of dense fabric with double walls.
Trays.
(Modified edition, Amendment No. 2).
13.3.Sample preparation
The laboratory sample is reduced to a mass of at least 1000 g, sieved on two sieves: the first with holes 5 mm in diameter and the second with a mesh No. 1.25 or 016, depending on the size of the test material, dried to constant weight, after which two weighed portions are taken weighing 400 g.
13.4.Testing
Each sample is placed in a bag that ensures the safety of the grains, immersed in a vessel with water for saturation for 48 hours. The bag with a sample is taken out of the water and placed in a freezer that ensures a gradual decrease in temperature to minus (20 ± 5) ° C.
Samples in the chamber at a steady-state temperature of minus (20 ± 5) ° С are kept for 4 hours, after which the bags with weighed portions are removed, immersed in a vessel with water having a temperature of 20 ° С, and kept for 2 hours.
Date of introduction01.07.89
This standard applies to sand used as aggregate for concrete in monolithic, precast concrete and reinforced concrete structures, as well as material for the corresponding types of construction work, and specifies the test methods.
1. General Provisions
1.1. The scope of the sand test methods specified in this standard is indicated in the appendix.
1.2. Samples are weighed to an accuracy of 0.1% by weight, unless otherwise specified in the standard.
1.3. Samples or weighed portions of sand are dried to constant weight in a drying oven at a temperature of (105 ± 5) ° С until the difference between the results of two weighings is not more than 0.1% of the mass. Each subsequent weighing is carried out after drying for at least 1 hour and cooling for at least 45 minutes.
1.4. The test results are calculated to the second decimal place, unless other instructions are given regarding the accuracy of the calculation.
1.5. The test result is taken as the arithmetic mean of the parallel determinations provided for the corresponding method.
1.6. The standard set of sand screens includes 10 round-hole screens; 5 and 2.5mm and wire sieves with standard square meshes No. 1.25; 063; 0315; 016; 005 in accordance with GOST 6613 (sieve frames are round or square with a diameter or side side of at least 100 mm).
Note. The use of sieves with nets No. 014 is allowed before equipping enterprises with sieves with nets No. 016.
1.7. The temperature of the room in which the tests are carried out shall be (25 ± 10) ° C. Before starting the test, sand and water should be at a temperature corresponding to the temperature of the air in the room.
1.8. Water for testing is used in accordance with GOST 2874 or GOST 23732, if the standard does not provide instructions on the use of distilled water.
1.9. When using hazardous (caustic, toxic) reagents, substances should be guided by the safety requirements set out in the regulatory and technical documents for these reagents.
1.10. The "Hardware" sections provide links to national standards. The use of similar imported equipment is allowed. The non-standard measuring instruments used, specified in the "Equipment" section, must undergo metrological certification in accordance with GOST 8.326.
________________________________________________________________________________
Official edition Reprinting prohibited
© Standards Publishing House, 1988
© IPK Publishing house of standards, 1998
Reissue with Changes
S. 2 GOST 8735-88
| Designation | GOST 8735-88 |
| Title in Russian | Sand for construction work. Test methods |
| Title in English | Sand for construction work. Testing methods |
| Effective date | 01.07.1989 |
| OKS | 91.100.15 |
| KGS code | F19 |
| OKSTU code | 5711 |
| GRNTI heading index | 670181 |
| Abstract (scope) | This standard applies to sand used as an aggregate for concrete in monolithic, precast concrete and reinforced concrete structures, as well as a material for relevant types of construction work, and specifies test methods. |
| Keywords | construction ; aggregate for monolithic concrete; aggregate for precast concrete structures; aggregate for reinforced concrete structures; material for the corresponding types of construction work; |
| Type of standard | Control standards |
| Designation of the replaceable (s) | GOST 8735-75; GOST 25589-83 |
| Normative references to: GOST | GOST 8.326-89; GOST 83-79; GOST 427-75; GOST 450-77; GOST 1277-75; GOST 1770-74; GOST 2184-77; GOST 2874-82; GOST 3118-77; GOST 3760-79; GOST 4108-72; GOST 4159-79; GOST 4204-77; GOST 4220-75; GOST 4232-74; GOST 4328-77; GOST 4461-77; GOST 6613-86; GOST 6709-72; GOST 8269.0-97; GOST 8736-93; GOST 9147-80; GOST 10163-76; GOST 22524-77; GOST 23732-79; GOST 23932-90; GOST 24104-2001; GOST 25336-82; GOST 25706-83; GOST 27068-86; GOST 29329-92; GOST R 51232-98 |
| Normative references to: Others | TU 6-09-1706-82; TU 6-09-5169-84; PR 50.2.009-94 |
| The document was submitted by the CIS organization | Ministry of Industry and Construction Materials of the USSR |
| Rostekhregulirovanie Department | 50 - Ministry of Construction of the Russian Federation |
| MND developer | Russian Federation |
| Date of last edition | 01.11.2006 |
| Change number (s) | reprint with rev. 1; 2 |
| Number of pages (original) | 26 |
| Organization - Developer | Ministry of Industry and Construction Materials of the USSR |
| Status | Active |
GOST 873588
(ST SEV 5446 * 85)
ST SEV 6317 * 88
UDC 691.223.001.4.006.354 Group Ж19
STATE STANDARD OF THE UNION OF SSR
SAND FOR CONSTRUCTION WORKS
Test methods
Sand for construction work.
Testing methods
OKSTU 5711
Date of introduction 01.07.89
Failure to comply with the standard is punishable by law
This standard applies to sand used as aggregate for concrete in monolithic, precast concrete and reinforced concrete structures, as well as material for the corresponding types of construction work, and specifies test methods.
1. GENERAL PROVISIONS
1.1. The scope of the sand test methods specified in this standard is indicated in the appendix.
1.2. Samples are weighed to an accuracy of 0.1% by weight, unless otherwise specified in the standard.
1.3. Samples or weighed portions of sand are dried to constant weight in a drying oven at a temperature of (105 ± 5) ° From until the difference between the results of two weighings is no more than 0.1% of the mass. Each subsequent weighing is carried out after drying for at least 1 hour and cooling for at least 45 minutes.
1.4. The test results are calculated to the second decimal place, unless other instructions are given regarding the accuracy of the calculation.
1.5. The test result is taken as the arithmetic mean of the parallel determinations provided for the corresponding method.
1.6. The standard set of sand screens includes 10 round-hole screens; 5 and 2.5 mm and wire sieves with standard square meshes No. 1.25; 063; 0315; 016; 005 in accordance with GOST 6613 (sieve frames are round or square with a diameter or side side of at least 100 mm).
Note. The use of sieves with nets No. 014 is allowed before equipping enterprises with sieves with nets No. 016.
1.7. The temperature of the room in which the tests are carried out shall be (25 ± 10) ° C. Before starting the test, sand and water should be at a temperature corresponding to the temperature of the air in the room.
1.8. Water for testing is used in accordance with GOST 2874 or GOST 23732, if the standard does not provide instructions on the use of distilled water.
1.9. When using hazardous (caustic, toxic) substances as reagents, one should be guided by the safety requirements set forth in the regulatory and technical documents for these reagents.
1.10. The Hardware sections provide links to national standards. The use of similar imported equipment is allowed. The non-standard measuring instruments used, specified in the Equipment section, must undergo metrological certification in accordance with GOST 8.326.
2. SAMPLING
2.1. During acceptance control at the manufacturing plant, spot samples are taken, from which, by mixing, one combined sample is obtained from the replaceable product of each technological line.
2.2. Sampling of point samples from technological lines transporting products to a warehouse or directly to vehicles is carried out by crossing the material flow on a belt conveyor or at points of a material flow difference using samplers or manually.
To check the quality of sand shipped directly to the open pit face, spot samples are taken during loading into vehicles.
2.3. Spot samples to obtain a combined sample begin to be taken 1 hour after the start of the shift and then taken every hour during the shift.
The sampling interval for manual sampling can be increased if the manufacturer produces products of consistent quality. To establish the permissible sampling interval, the coefficient of variation of the values of the content of grains passing through a sieve with a mesh No. 016 and the content of dust and clay particles is determined on a quarterly basis. To determine the coefficient of variation of these indicators during the shift, every 15 minutes, spot samples with a mass of at least 2000 are taken. For each spot sample, the content of grains passing through a sieve with a mesh No. 016, and the content of dust and clay particles are determined. Then the coefficients of variation of these indicators are calculated in accordance with GOST 8269.
Depending on the obtained maximum value of the coefficient of variation for the two determined indicators, the following intervals for taking spot samples during the shift are taken:
3 hours with a coefficient of variation of the indicator up to 10%;
2 hours 15%.
2.4. The mass of a spot sample with a sampling interval of 1 h should be at least 1500 g. four times.
If, when taking samples with a sampler, the mass of the spot sample turns out to be less than the specified one by more than 100 g, then it is necessary to increase the number of samples taken to ensure that the mass of the combined sample is at least 10,000 g.
2.5. The pooled sample is mixed and cut by quartering or using a fluted divider to obtain a laboratory sample prior to shipment to the laboratory.
To quarter the sample (after mixing it), the material cone is leveled and divided into four parts by mutually perpendicular lines passing through the center. Any two opposite quarters are sampled. By successive quartering, reduce the sample by two, four times, etc., until a sample with a mass corresponding to clause 2.6 is obtained.
2.6. The mass of a laboratory sample during acceptance control at the manufacturer must be at least 5000 g, it is used for all tests provided for during acceptance control.
When conducting periodic tests, as well as during incoming control and when determining the properties of sand during geological exploration, the mass of the laboratory sample must ensure that all tests provided for by the standard are carried out. It is allowed to carry out several tests using one sample, if the determined properties of the sand do not change during the tests, and the mass of the laboratory sample must be at least twice the total mass required for the tests.
2.7. An analytical sample is taken from the laboratory sample for each test.
Samples are taken from the analytical sample in accordance with the test procedure.
2.8. For each laboratory sample intended for periodic testing in the central laboratory of the association or in a specialized laboratory, as well as for arbitration tests, a sampling report is drawn up, including the name and designation of the material, the place and date of sampling, the name of the manufacturer, the designation of the sample and the signature of the responsible for taking a sample of the face.
Selected samples are packed in such a way that the mass and properties of the materials do not change prior to testing.
Each sample is provided with two labels with the sample designation. One label is placed inside the package, the other in a prominent place on the package.
During transportation, the packaging must be protected from mechanical damage and moisture.
2.9. To check the quality of sand extracted and laid by hydromechanization, the reclamation map is divided in plan along the length (along the alluvium map) into three parts.
Point samples are taken from each part from at least five different locations (in plan). To take a spot sample, dig a hole 0.20.4 m deep. From the hole, a sample of sand is taken with a scoop, moving it from bottom to top along the wall of the hole.
A combined sample is obtained from the spot samples by mixing, which is reduced to obtain a laboratory sample according to clause 2.5.
The quality of the sand is assessed separately for each part of the reclamation map according to the results of testing a sample taken from it.
2.10. During arbitration testing of the quality of sand in warehouses, spot samples are taken with a scoop in places located evenly over the entire surface of the warehouse, from the bottom of dug holes 0.20.4 m deep. The holes should be staggered. The distance between the holes should not exceed 10 m. The laboratory sample is prepared according to clause 2.5.
2.11. During the incoming inspection at the consumer enterprise, a combined sample of sand is taken from the tested batch of material in accordance with the requirements of GOST 8736. A laboratory sample is prepared in accordance with clause 2.5.
2.12. During geological exploration, samples are taken in accordance with the normative and technical documentation approved in the prescribed manner.
3. DETERMINATION OF GRAIN COMPOSITION AND COARSE MODULE
3.1. The essence of the method
The grain size distribution is determined by sieving the sand on a standard set of sieves.
3.2. Equipment
A set of sieves in accordance with GOST 6613 and sieves with round holes with a diameter of 10; 5 and 2.5 mm.
Drying cabinet.
3.3. Test preparation
An analytical sample of sand weighing at least 2000 g is dried to constant weight.
3.4. Testing
A sample of sand dried to constant weight is sieved through sieves with round holes 10 and 5 mm in diameter.
Residues on sieves are weighed and the content of gravel fractions with a grain size of 5 to 10 mm ( Gr 5) and St. 10 mm ( Gr 10) in percentage by weight according to the formulas:
where M 10 residue on a sieve with round holes with a diameter of 10 mm, g;
M 5 residue on a sieve with round holes 5 mm in diameter, g;
M sample weight, g.
From a part of the sand sample that has passed through a sieve with holes 5 mm in diameter, a sample weighing at least 1000 g is taken to determine the grain size composition of the sand.
It is allowed for geological exploration to disperse the sample after preliminary flushing with the determination of the content of dust and clay particles. The content of dusty and clay particles is included when calculating the results of sieving in the mass of particles passing through a sieve with a mesh No. 016, and in the total weight of the sample. In mass tests, after washing with the determination of the content of dusty and clay particles and drying the sample to constant weight, it is allowed to sift a sample of sand (without gravel fraction) weighing 500 g.
The prepared sample of sand is sieved through a set of sieves with round holes 2.5 mm in diameter and with meshes No. 1.25; 063; 0315 and 016.
Sifting is done mechanically or manually. The duration of sieving should be such that, with control intensive manual shaking of each sieve for 1 min, no more than 0.1% of the total mass of the sieved sample passes through it. With mechanical sieving, its duration for the device used is established empirically.
With manual sieving, it is allowed to determine the end of sieving by vigorously shaking each sieve over a sheet of paper. Sifting is considered complete if there is practically no falling of sand grains.
When determining the grain size composition by the wet method, a sample of the material is placed in a vessel and filled with water. After 24 hours, the contents of the vessel are thoroughly mixed until the clay film is completely soaked onto grains or lumps of clay, poured (in portions) onto the top sieve of a standard set and sieved, rinsing the material on sieves until the wash water becomes clear. The partial residues on each sieve are dried to constant weight and cooled to room temperature, then their weight is determined by weighing.
(Modified edition, Amendment No. 1).
3.5. Processing of results
Based on the results of sifting, the following is calculated:
The partial residue on each sieve ( a i) as a percentage according to the formula
where t i the mass of the residue on a given sieve, g;
T weight of the sieved sample, g;
The total residue on each sieve ( A i) as a percentage according to the formula
where a 2,5 , a 1,25 , a i partial residues on the respective sieves;
Sand fineness module ( M j) without grains larger than 5 mm according to the formula
where A 2,5 , A 1,25 , A 063 , A 0315 , A 016 complete residues on a sieve with round holes with a diameter of 2.5 mm and on sieves with mesh No. 1.25; 063; 0315, 016,%.
The result of determining the grain size composition of sand is drawn up in accordance with table. 1 or depicted graphically in the form of a sieving curve in accordance with fig. 1.
Sieving curve
Heck. 1
Table 1
|
Residues,% by weight, on sieves |
Passage through |
|||||
|
Remainder name |
1,25 |
0,63 |
0,315 |
0,16 (0,14) |
sieve with mesh № 016(014), % by weight |
|
|
Private |
a 2,5 |
a 1,25 |
a 063 |
a 0315 |
a 016(014) |
a 016(014) |
|
Full |
A 2,5 |
A 1,25 |
A 063 |
A 0315 |
A 016(014) |
|
4. DETERMINATION OF CLAY CONTENT IN LUMPS
4.1. The essence of the method
4.2. Equipment
Scales in accordance with GOST 23711 or GOST 24104.
Drying cabinet.
Sieves with mesh No. 1.25 in accordance with GOST 6613 and with round holes 5 and 2.5 mm in diameter.
Mineralogical magnifier in accordance with GOST 25706.
The needle is steel.
4.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes with a diameter of 5 mm, take from it at least 100 g of sand, dried to constant weight and scattered on sieves with holes with a diameter of 2.5 mm and a mesh No. 1.25. From the obtained sand fractions, weighed samples are taken with a mass:
5.0 g of St. 2.5 to 5 mm;
1.0 g fraction from 1.25 to 2.5 mm
Each weighed amount of sand is poured into a thin layer on glass or metal sheet and moistened with a pipette. Clumps of clay, differing in viscosity from sand grains, are isolated from the sample with a steel needle, using a magnifying glass if necessary. The sand grains remaining after the separation of lumps are dried to constant weight and weighed.
4.4. Processing of results
where m 1 , m 2 the weight of the sample of sand of the fraction, respectively, from 2.5 to 5 mm and from 1.25 to 2.5 mm before the release of clay, g;
T 1, m 3 masses of sand grains, fraction, respectively, from 2.5 to 5 mm and from 1.25 to 2.5 mm after the separation of clay, g.
where a 2,5 , a 1.25 partial residues in percent by weight on sieves with openings of 2.5 and 1.25 mm, calculated according to clause 3.5.
5. DETERMINATION OF THE CONTENT OF DUST AND CLAY PARTICLES
5.1. Elimination method
5.1.1. The essence of the method
5.1.2. Equipment
Scales in accordance with GOST 23711 or GOST 24104.
Drying cabinet.
A cylindrical bucket with a height of at least 300 mm with a siphon or a vessel for eluting sand (Fig. 2).
Stopwatch.
5.1.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter, the sand that has passed through the sieve is dried to constant weight and a sample of 1000 g is taken from it.
5.1.4. Testing
A weighed amount of sand is placed in a cylindrical bucket and filled with water so that the height of the water layer above the sand is about 200 mm. The sand filled with water is kept for 2 hours, stirring it several times, and thoroughly washed from the clay particles adhering to the grains.
Thereafter, the contents of the bucket are vigorously mixed again and left alone for 2 minutes. After 2 minutes, drain the suspension obtained during washing with a siphon, leaving its layer above the sand with a height of at least 30 mm. Then the sand is again poured with water to the above level. Washing the sand in this sequence is repeated until the water after washing remains clear.
When using an elutriation vessel, the test is carried out in the same sequence. In this case, water is poured into the vessel up to the upper drain hole, and the suspension is poured through the two lower holes.
After elutriation, the washed sample is dried to constant weight T 1 .
5.1.5. Processing of results
where T weight of the dried sample before elutriation, g;
m1 mass of dried sample after elutriation, g.
Exhaustion vessel
Heck. 2
Notes:
1. When testing natural sands, the grains of which are densely cemented with clay, the sample is kept in water for at least 1 day.
2. It is allowed to test sand in a state of natural moisture. In this case, in a parallel sample, the moisture content of the sand and the content of dust and clay particles ( NS mark) is calculated as a percentage by the formula
(10)
where T in the weight of the sample in a state of natural moisture, g;
T 1 weight of the sample, dried after elutriation to constant weight, g;
W humidity of the tested sand,%.
5.2. Pipette method
5.2.1. The essence of the method
5.2.2. Equipment
Scales in accordance with GOST 29329 or GOST 24104.
The bucket is cylindrical with two marks (belts) on the inner wall, corresponding to a capacity of 5 and 10 liters.
The bucket is cylindrical without marks.
Drying cabinet.
Sieves with mesh No. 063 and 016 in accordance with GOST 6613.
Metal cylinders with a capacity of 1000 ml with a viewing window (2 pcs.).
Metallic pipette with a volume of 50 ml (Fig. 3).
Funnel with a diameter of 150 mm.
Stopwatch.
A cup or glass for evaporation in accordance with GOST 9147.
5.2.3. Testing
A sample of sand weighing about 1000 g in a state of natural moisture is weighed, placed in a bucket (without a label) and filled with 4.5 liters of water. In addition, about 500 ml of water is prepared for subsequent rinsing of the bucket.
The sand filled with water is kept for 2 hours, stirring it several times, and thoroughly washed from the clay particles adhering to the grains. Then the contents of the bucket are poured carefully onto two sieves: the upper one with mesh No. 063 and the lower one with mesh No. 016, placed on a bucket with marks.
The suspensions are allowed to settle and the clarified water is carefully poured into the first bucket. The sand is washed again with the drained water on sieves over the second bucket (with marks). After that, the first bucket is rinsed with the water left and this water is drained into the second bucket. At the same time, such an amount of the left water is used so that the level of the suspension in the latter reaches exactly the 5 l mark; if the remaining water is not enough for this, the volume of the suspension is brought to 5 liters by adding additional water.
After that, the suspension is thoroughly mixed in a bucket and immediately filled with it using a funnel, alternately two metal cylinders with a capacity of 1000 ml, while continuing to stir the suspension. The slurry level in each cylinder must match the mark on the sight glass.
The suspension in each cylinder is stirred with a glass or metal rod or the cylinder is overturned several times, closing it with a lid for better mixing.
After the end of stirring, leave the cylinder at rest for 1.5 minutes. 510 s before the end of exposure, a graduated pipette with a tube closed by a finger is lowered into the cylinder so that the support cap rests on the top of the cylinder wall, while the bottom of the pipette will be at the level of the suspension withdrawal 190 mm from the surface. After the specified time (510 s), open the pipette tube and after filling it again close the tube with a finger, remove the pipette from the cylinder and, opening the tube, pour the contents of the pipette into a previously weighed cup or glass. The filling of the pipette is controlled by the change in the level of the suspension in the viewing window.
Metal cylinder and volumetric pipette
1 cylinder; 2 pipette; 3 label (1000 ml);
4 slurry level in the cylinder
Heck. 3
Instead of metal cylinders with a viewing window and a special pipette, it is allowed to use ordinary glass measuring cylinders with a capacity of 1 l and a glass pipette with a capacity of 50 ml, lowering it into the cylinder to a depth of 190 mm.
The suspension in a cup (glass) is evaporated in an oven at a temperature of (105 ± 5) ° C. The cup (glass) with the evaporated powder is weighed on a balance with an error of up to 0.01 g. Similarly, a sample of the suspension is taken from the second cylinder.
5.2.4. Processing of results
(11)
where T weight of a sample of sand, g;
Directory of GOSTs, TU, standards, norms and rules. SNiP, SanPiN, certification, technical conditionsSTATE STANDARD OF THE UNION OF SSR
SAND FOR CONSTRUCTION WORKS
TEST METHODS
GOST 8735-88
(ST SEV 5446-85)
ST SEV 6317-88
STATE CONSTRUCTION COMMITTEE of the USSR
STATE STANDARD OF THE UNION OF SSR
| SAND FOR CONSTRUCTION WORKS Test methods Sand for construction work. | GOST 8735-88 (ST SEV 5446-85) |
Date of introduction 01.07.89
Failure to comply with the standard is punishable by law
This standard applies to sand used as an aggregate for concrete in monolithic, precast concrete and reinforced concrete structures, as well as a material for related types of construction work, and specifies test methods.
1. GENERAL PROVISIONS
1.1. The scope of the sand test methods specified in this standard is indicated in the appendix.
1.2. Samples are weighed to an accuracy of 0.1% by weight, unless otherwise specified in the standard.
1.3. Samples or weighed portions of sand are dried to constant weight in a drying oven at a temperature of (105 ± 5) ° С until the difference between the results of two weighings is not more than 0.1% of the weight. Each subsequent weighing is carried out after drying for at least 1 hour and cooling for at least 45 minutes.
1.4. The test results are calculated to the second decimal place, unless other instructions are given regarding the accuracy of the calculation.
1.5. The test result is taken as the arithmetic mean of the parallel determinations provided for the corresponding method.
1.6. The standard set of sand screens includes screens with round holes with diameters of 10; 5 and 2.5 mm and wire sieves with standard square meshes No. 1.25; 063; 0315; 016; 005 in accordance with GOST 6613-86 (sieve frames are round or square with a diameter or side of at least 100 mm).
Note. The use of sieves with meshes No. 014 is allowed to retrofit enterprises with sieves with meshes No. 016.
1.7. The temperature of the room in which the tests are carried out shall be (25 ± 10) ° C. Before starting the test, the sand and water should be at a temperature corresponding to the room temperature.
1.8. Water for testing is used in accordance with GOST 2874-82 or GOST 23732-79, if the standard does not provide instructions on the use of distilled water.
1.9. When using hazardous (caustic, toxic) substances as reagents, one should be guided by the safety requirements set out in the regulatory and technical documents for these reagents.
1.10. For testing, it is allowed to use imported equipment similar to that given in this standard.
Non-standardized measuring instruments must pass metrological certification in accordance with GOST 8.326-89.
(Modified edition. Amendment No. 2).
2. SAMPLING
2.1. At the acceptance control of the manufacturer, point samples are taken, from which, by mixing, one combined sample is obtained from the replaceable product of each technological line.
2.2. Sampling of point samples of technological lines transporting products to a warehouse or directly to vehicles is carried out by crossing the material flow on a belt conveyor or at points of a material flow difference using samplers or manually.
To check the quality of the sand shipped directly to the open pit face, spot samples are taken during loading into vehicles.
2.3. Accurate samples to obtain a combined sample begin to be taken 1 hour after the start of the shift and then taken every hour during the shift.
The sampling interval for manual sampling can be increased if the manufacturer produces products of consistent quality. To establish the permissible sampling interval, the coefficient of variation of the values of the content of grains passing through a sieve with a mesh No. 016 and the content of dusty and clay particles is determined on a quarterly basis. To determine the coefficient of variation of these indicators, during the shift every 15 minutes, point samples with a mass of at least 2000 g are taken. For each spot sample, the content of grains passing through the sieve mesh No. 016 and the content of dusty and clay particles are determined. Then the coefficients of variation of these indicators are calculated in accordance with GOST 8269.0-97.
Depending on the obtained maximum value of the coefficient of variation for the two determined indicators, the following intervals for taking spot samples during the shift are taken:
3 hours - with a coefficient of variation of the indicator up to 10%;
2 hours "" "" "15%.
(Modified edition, Amendment No. 2).
2.4. The mass of a spot sample at a sampling interval of 1 hour should be at least 1500 g. When the sampling interval is increased in accordance with clause 2.3, the mass of a sampled spot sample should be doubled at an interval of 2 h, and four times at an interval of 3 h.
If, when taking a sampler with a sampler, the mass of a spot sample turns out to be less than the specified one by more than 100 g, then it is necessary to increase the number of samples taken to ensure that the mass of the combined sample is at least 10,000 g.
2.5 The pooled sample is mixed and cut by quartering or using a fluted divider to obtain a laboratory sample prior to shipment to the laboratory.
To quarter the sample (after mixing), the material cone is leveled and divided into four parts by mutually perpendicular lines passing through the center. Any two opposite quarters are sampled. By successive quartering, the sample is reduced by two, four times, etc. until a sample is obtained with a mass corresponding to clause 2.6.
2.6. The mass of a laboratory sample during acceptance control at the manufacturing plant should be at least 5000 g, it is used for all tests provided for during acceptance control.
When conducting periodic tests, as well as during incoming control and when determining the properties of sand during geological exploration, the mass of the laboratory sample must ensure that all tests provided for by the standard are carried out. It is allowed to carry out several tests using one sample, if the determined properties of the sand do not change during the tests, while the mass of the laboratory sample must be at least twice the total mass required for the tests.
2.7. An analytical sample is taken from the laboratory sample for each test.
Samples are taken from the analytical sample in accordance with the test procedure.
2.8. For each laboratory sample intended for periodic testing in the central laboratory of the association or in a specialized laboratory, as well as for arbitration tests, a sampling report is drawn up, including the name and designation of the material, the place and date of sampling, the name of the manufacturer, the designation of the sample and the signature of the person responsible for sampling ...
Selected samples are packaged in such a way that the weight and properties of the materials are not altered prior to testing.
Each sample is provided with two labels with the sample designation. One label is placed inside the package, the other in a prominent place on the package.
During transportation, the package must be protected from mechanical damage and moisture.
2.9. To check the quality of the sand, mined and laid by the hydromechanization method, the reclamation map is divided in the plan along the length (along the alluvium map) into three parts.
Point samples are taken from each part from at least five different locations (in plan). To take a spot sample, a hole is dug with a depth of 0.2-0.4 m. From the hole, a sample of sand is taken with a scoop, moving it from bottom to top along the wall of the hole.
From point samples by mixing, a combined sample is obtained, which is reduced to obtain a laboratory sample according to clause 2.5.
The quality of the sand is assessed separately for each part of the reclamation map according to the test results of a sample taken from it.
2.10. In the arbitration check of the quality of sand in warehouses, spot samples are taken with a scoop in places located evenly over the entire surface of the warehouse, from the bottom of dug holes 0.2-0.4 m deep. The holes should be staggered. The distance between the holes should not exceed 10 m. The laboratory sample is prepared according to clause 2.5.
2.11. During the incoming inspection at the consumer enterprise, the combined sand sample is taken from the checked batch of material in accordance with the requirements of GOST 8736-85. A laboratory sample is prepared in accordance with clause 2.5.
2.12. During geological exploration, samples are taken in accordance with the normative and technical documentation approved in the prescribed manner.
3. DETERMINATION OF GRAIN COMPOSITION AND COARSE MODULE
3.1. The essence of the method
The grain size composition is determined by sieving the sand on a standard set of sieves.
3.2. Equipment
Scales in accordance with GOST 24104-88.
A set of sieves in accordance with GOST6613-86 and sieves with round holes with a diameter of 10; 5 and 2.5mm.
Drying cabinet.
3.3. Test preparation
An analytical sample with a sand mass of at least 2000 g is dried to constant weight.
3.4. Testing
A sample of sand dried to constant weight is sieved through sieves with round holes 10 and 5 mm in diameter.
Residues on sieves are weighed and the content of gravel fractions with a grain size of 5 to 10 mm ( Gr 5) and St. 10 mm ( Gr 10) in percentage by weight according to the formulas:
(1)
(2)
where M 10 - the remainder of a sieve with round holes with a diameter of 10 mm, g;
M 5 - residue on a sieve with round holes 5 mm in diameter, g;
M - sample weight, g.
From a part of the sand sample that has passed through a sieve with holes 5 mm in diameter, a sample weighing at least 1000 g is taken to determine the grain size composition of the sand.
It is allowed during geological exploration to disperse the sample after preliminary flushing by determining the content of dust and clay particles. The content of dust-like acicular particles is included when calculating the results of sieving in the mass of particles passing through a sieve with a mesh No. 016, and in the total weight of the sample. In mass tests, after washing with the determination of the content of dust-like acicular particles and drying the sample to constant weight, it is allowed to sift a sample (without gravel fraction) weighing 500 g.
The prepared sample of sand is sifted through a set of sieves with round holes 2.5 mm in diameter and with meshes No. 1.25; 063; 0315 and 016.
Sifting is carried out mechanically or manually. The duration of sieving should be such that, with a control intensive manual shaking of each sieve for 1 min, no more than 0.1% of the total mass of the sieved sample passes through it for 1 min. With mechanical sieving, its duration for the device used is set empirically.
With manual sieving, it is allowed to determine the end of sieving by vigorously shaking each siton with a sheet of paper. Sifting is considered complete if there is practically no falling of sand grains.
When determining the grain composition by the wet method, a sample of the material is placed into a vessel and poured with water. After 24 hours, the contents of the vessel are thoroughly mixed until the clay film is completely soaked onto grains or lumps of clay, poured (in portions) onto the upper sieve of a standard set and sieved, washing the material on sieves until then, until the wash water becomes clear. Partial residues on each sieve are dried to constant weight and cooled to room temperature, then their weight is determined by weighing.
(Modified edition, Amendment No. 1).
3.5. Processing of results
Based on the results of sieving, calculate: the partial residue on each sieve ( ai) as a percentage according to the formula
where t i - the mass of the residue on a given sieve, g;
T - weight of the sieved sample, g;
the total balance on each site ( Ai) as a percentage according to the formula
where a 2,5 , a 1,25 ,a i- partial remains on the respective sieves;
sand size modulus ( M j) without grains larger than 5 mm according to the formula
(5)
where A 2,5 , A 1,25 ,A 063 , A 0315 , A 016 - complete residues on a sieve with round holes 2.5 mm in diameter and on sieves with mesh No. 1.25; 063; 0315, 016,%.
The result of determining the grain composition of sand is drawn up in accordance with table. 1 or depicted graphically in the form of a sieving curve in accordance with Fig. 1.
Sieving curve
Table 1
4. DETERMINATION OF CLAY CONTENT IN LUMPS
4.1. The essence of the method
4.2. Equipment
Scales in accordance with GOST 24104-88.
Drying cabinet.
Sieves with mesh No. 1.25 in accordance with GOST6613-86 and with round holes 5 and 2.5 mm in diameter.
The needle is steel.
(Modified edition, Amendment No. 2).
4.3. Test preparation
An analytical sample is sieved through a sieve with holes 5 mm in diameter, at least 100 g of sand is taken from it, dried to constant weight and scattered on sieves with holes with a diameter of 2.5 mm and mesh No. 1.25. Samples are taken from the obtained sand fractions:
5.0 g - fraction of St. 2.5 to 5mm;
1.0 g - fractions from 1.25 to 2.5 mm
Each weighed portion of sand is poured into a thin layer on glass or metal sheet and moistened with a pipette. Clumps of clay, differing in viscosity, are isolated from the sample with a steel needle. from sand grains, using a magnifying glass if necessary. Remaining after the separation of lumps of sand grains are dried to constant weight and weighed.
4.4.Processing of results
(6)
(7)
where m 1 , m 2 - weights of the sample of sand fraction, respectively, from 2.5 to 5 mm and from 1.25 to 2.5 mm before the release of clay, g;
T 1 ;m 3 - mass grains of sand, fraction, respectively, from 2.5 to 5 mm and from 1.25 to 2.5 mm after clay precipitation, g.
(8)
where a 2,5 , a 1.25 - partial residues in percent by weight on sieves with openings of 2.5 and 1.25 mm, calculated according to clause 3.5.
5. DETERMINATION OF THE CONTENT OF DUST AND CLAY PARTICLES
5.1. Elimination method
5.1.1. The essence of the method
5.1.2. Equipment
Scales in accordance with GOST 24104-88.
Drying cabinet.
A cylindrical bucket with a height of at least 300 mm with a siphon or a vessel for grinding sand (Fig. 2).
Stopwatch in accordance with GOST 5072-79.
(Modified edition, Amendment No. 2).
5.1.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter, the sand that has passed through the sieve is dried to constant weight and a sample of 1000 g is taken from it.
5.1.4. Testing
A weighed amount of sand is placed in a cylindrical bucket and filled with water so that the height of the water layer above the sand is about 200 mm. The sand filled with water is kept for 2 hours, stirring it several times, and thoroughly washed from the clay particles adhering to the grains.
After that, the contents of the vedrasnov are vigorously stirred and left alone for 2 minutes. After 2 min, drain the suspension obtained by washing with a siphon, leaving its layer above the sand with a height of at least 30 mm. Then the pesoksnova is poured with water to the level indicated above. Washing the sand in the specified sequence is repeated until the water after washing remains clear.
If a test vessel is used for elutriation, the test is carried out in the same sequence. In this case, water is poured into the vessel up to the upper drain hole, and the suspension is poured through the two lower holes.
After elutriation, the washed sample is dried to constant weight T 1 .
5.1.5. Processing of results
(9)
where T - weight of the dried sample before elutriation, g;
m 1 - the mass of the dried sample after elutriation, g.
Exhaustion vessel
Notes:
1. When testing natural sands, the grains of which are tightly cemented by clay, the sample is kept in water for less than 1 day.
2. It is allowed to test sand in a state of natural moisture. In this case, the moisture content of the sand and the content of dust-like acicular particles ( NS mark) is calculated as a percentage by the formula
(10)
where T c - weight of the sample in the state of natural moisture, g;
T 1 - weight of the sample, dried after elutriation to constant weight, g;
W- humidity of the tested sand,%.
5.2. Pipette method
5.2.1. The essence of the method
5.2.2. Equipment
Scales in accordance with GOST 24104-88.
The bucket is cylindrical with two marks (belts) on the inner wall, corresponding to a capacity of 5 and 10 liters.
Cylindrical bucket without marks.
Drying cabinet.
Sieves with mesh No. 063 and 016 according to GOST6613-86.
Metal cylinders with a capacity of 1000 ml with a viewing window (2 pcs.).
Metallic volumetric pipette with a capacity of 50 ml (Fig. 3).
Funnel with a diameter of 150 mm.
Stopwatch in accordance with GOST 5072-79
A cup or glass for steaming in accordance with GOST 9147-80.
(Modified edition, Amendment No. 2).
5.2.3. Testing
A sample of sand weighing about 1000 g in a state of natural moisture is weighed, placed in a bucket (without marks) and filled with 4.5 liters of water. In addition, about 500 ml of water is prepared for subsequent rinsing of the bucket.
The sand filled with water is kept for 2 hours, stirring it several times, and thoroughly washed from the clay particles adhering to the grains. Then the contents of the bucket are poured carefully onto two sieves: the upper one with mesh No. 063 and the lower one with mesh No. 016, placed on a bucket with marks.
The suspensions are allowed to settle and the clarified water is carefully poured into the first bucket. With the drained water, the sand is re-washed on sieves over the second bucket (with marks). After that, the first bucket is rinsed with the water left and this water is poured into the second bucket. At the same time, use such an amount of the left water that the level of the suspension in the last reaches exactly the mark of 5 liters; if the remaining water is not enough for this, the volume of the suspension is brought to 5 liters by adding an additional amount of water.
After that, the suspension is thoroughly mixed in a bucket and immediately filled with it using a funnel, alternately two metal cylinders with a capacity of 1000 ml, while continuing to stir the suspension. The slurry level in each cylinder must match the mark on the sight glass.
The suspension in each cylinder is stirred with a glass or metal rod, or the cylinder is tilted several times, closing it with a lid, for better mixing.
After the end of stirring, leave the cylinder at rest for 1.5 minutes. 5-10 s before the end of the exposure, a graduated pipette with a tube closed with a finger is lowered into the cylinder so that the support cap rests on the top of the cylinder wall, while the bottom of the pipette will be at the level of suspension withdrawal - 190 mm from the surface. After the specified time (5-10 s), open the pipette tube and after filling it again close the tube with a finger, remove the pipette from the cylinder and, opening the tube, pour the contents of the pipette into a previously weighed cup or glass. The filling of the pipette is controlled by the change in the level of the suspension in the viewing window.
Metal cylinder Measuring pipette
1 - cylinder; 2 - pipette; 3 - label (1000 ml); 4 - slurry level in the cylinder
Instead of metal cylinders with a viewing window and a special pipette, it is allowed to use ordinary glass measuring cylinders with a capacity of 1 l and a glass pipette with a capacity of 50 ml, lowering it into the cylinder to a depth of 190 mm.
The suspension in a cup (glass) is evaporated in an oven at a temperature of (105 ± 5) ° C. The cup (glass) with the evaporated powder is weighed on a balance with an error of up to 0.01 g. Similarly, a sample of the suspension is taken from the second cylinder.
5.2.4. Processing of results
(11)
where T - weight of a sample of sand, g;
T 1 - the mass of the cup or glass for evaporation of the suspension, g;
T 2 - weight of a cup or glass with evaporated powder, g.
In the case of testing sand heavily contaminated with dust and clay particles, the volume of water for flushing is 10 liters instead of 5 liters. Correspondingly, the volume of the suspension is increased to 10 l by injecting with labels. In this case, the test result ( NS mark) in percentage is calculated by the formula
(12)
Note. Sludge mass allowed ( T 2 -T 1) determine by the density of the suspension by the formula
(13)
where T 3 - mass of the pycnometer with suspension, g;
T 4 - mass of the pycnometer by the roof, g;
r is the density of the sediment, g / cm 3 (taken equal to 2.65 g / cm 3).
The result of determining the mass of sediment T 2 -T 1 is introduced into formula (11).
5.3. Wet sieving method
5.3.1. The essence of the method
The test is carried out in accordance with GOST 8269.0-97, using a sample of sand weighing 1000 g and a sieve with a mesh No. 0315 and 005.
(Modified edition, Amendment No. 2).
5.4. Photoelectric method
5.4.1. The essence of the method
The method is based on comparing the degree of transparency of pure water and a suspension obtained by washing the sand.
The test is carried out in accordance with GOST 8269.0-97, using a sample of sand weighing 1000 g.
(Modified edition, Amendment No. 2).
6. DETERMINATION OF THE PRESENCE OF ORGANIC IMPURITIES
6.1. The essence of the method
The presence of organic impurities (humic substances) is determined by comparing the color of the alkaline solution above the sample of sand with the color of the standard.
6.2.
Scales in accordance with GOST 24104-88.
Photocolorimeter FEK-56M or spectrophotometer SF-4, or other similar devices.
Glass cylinders with a capacity of 250 ml made of transparent colorless glass (inner diameter 36-40 mm) in accordance with GOST 1770-74.
Bath water.
Sodium hydroxide (sodium hydroxide) in accordance with GOST 4328-77, 3% solution.
Tannin, 2% solution in 1% ethanol.
(Modified edition, Amendment No. 2).
6.3. Test preparation
A sample of about 250 g is taken from an analytical sample of sand in a state of natural moisture.
Prepare a standard solution by dissolving 2.5 ml of 2% tannin solution in 97.5 ml of 3% sodium hydroxide solution. The prepared solution is stirred and left for 24 hours.
The optical density of the tannin solution, determined on a photocolorimeter or spectrophotometer in the wavelength range of 450-500 nm, should be 0.60-0.68.
6.4. Testing
The measuring cylinder is filled with sand to a level of 130 ml and it is filled with a 3% sodium hydroxide solution to a level of 200 ml. The contents of the cylinder are stirred and left for 24 hours, stirring again 4 hours after the first stirring. Then compare the color of the liquid over the sample with the color of the standard solution or glass, the color of which is identical to the color of the standard solution.
Sand is suitable for use in concrete or mortars if the liquid above the sample is colorless or is much weaker than the standard solution.
When the color of the liquid is slightly lighter than the standard solution, the contents of the vessel are heated for 2-3 hours in a water bath at a temperature of 60-70 ° C and the color of the liquid above the sample is compared with the color of the standard solution.
When the color of the liquid is the same or darker than the color of the standard solution, it is necessary to test the aggregate in concrete or solutions in specialized laboratories.
7. DETERMINATION OF MINERAL AND PETROGRAPHIC COMPOSITION
7.1. The essence of the method
7.2. Equipment and reagents
Scales in accordance with GOST 24104-88.
A set of sieves with meshes No. 1.25; 063; 0315 and 016 in accordance with GOST6613-86 and with round holes with diameters of 5 and 2.5 mm.
Drying cabinet.
Binocular microscope with magnification from 10 to 50 C, polarizing microscope with magnification up to 1350 C.
Mineralogical magnifier GOST 25706-83.
A set of reagents.
The needle is steel.
(Modified edition, Amendment No. 2).
7.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter; at least 500 g of sand is sampled from the sieved part.
The sand is washed, dried to constant weight, scattered on a set of sieves with holes 2.5 mm in diameter and mesh No. 1.25; 063; 0315; 016 and take a sample with a mass of at least:
25.0 g - for sand with a grain size of St. 2.5 to 5.0 mm;
5.0 g "" "" "St. 1.25 to 2.5 mm;
1.0 g "" "" "St. 0.63 to 1.25 mm;
0.1 g "" "" "St. 0.315 to 0.63 mm;
0.01 g "" "" "from 0.16 to 0.315 mm.
7.4. Testing
Each sample is poured into a thin layer on glass or paper and viewed with a binocular microscope or magnifying glass.
Sand grains, represented by fragments of the corresponding rocks and minerals, are divided using a thin needle into groups according to the types of rocks and types of minerals.
If necessary, the determination of rocks and minerals is clarified using chemical reagents (hydrochloric acid solution, etc.), as well as by analysis in immersion liquids using a polarizing microscope.
In the grains of sand, represented by fragments of minerals, the content of quartz, feldspar, dark-colored minerals, calcite, etc. is determined.
Sand grains, represented by rock fragments, are divided according to genetic types in accordance with table. 2.
In addition, grains of rocks and minerals attributed to harmful impurities are emitted.
These rocks and minerals include: containing amorphous varieties of silicon dioxide (chalcedony, opal, flint, etc.); sulfur; sulfides (pyrite, marcasite, pyrrhotite, etc.); sulfates (gypsum, anhydrite, etc.); layered silicates (micas, hydromicas, chlorites, etc.); iron oxides and hydroxides (magnetite, goethite, etc.); apatite; nepheline; phosphorite; halide compounds (halite, sylvin, etc.); zeolites; asbestos; graphite; coal; oil shale.
In the presence of minerals containing sulfur, the amount of sulfate and sulfide compounds in terms of SO 3 is determined according to clause 12.
The quantitative determination of the content of potentially reactive varieties of silica is carried out according to clause 11.
The same weighed portions of sand are used to determine the shape and nature of the surface of sand grains in accordance with table. 3.
7.5. Processing of results
For each type of separated rocks and minerals, the number of grains is counted and their content is determined ( X) as a percentage in the sample according to the formula
where n - the number of grains of a given rock or mineral;
N - the total number of grains in the test sample.
8. DETERMINATION OF TRUE DENSITY
8.1. Pycnometric method
8.1.1. The essence of the method
True density is determined by measuring the mass per unit volume of dried sand grains.
8.1.2. Equipment
Piconometer with a capacity of 100 ml in accordance with GOST 22524-77.
Scales in accordance with GOST 24104-88.
Desiccator in accordance with GOST 25336-82.
Drying cabinet.
Sand bath or water bath.
Distilled water in accordance with GOST 6709-72.
(Modified edition, Amendment No. 2).
8.1.3. Test preparation
A sample of about 30 g is taken from the analytical sample, sieved through a sieve with holes 5 mm in diameter, dried to constant weight and cooled to room temperature in an exsiccator over concentrated sulfuric acid or anhydrous calcium chloride. The dried sand is mixed and divided into two parts.
8.1.4. Testing
Each part of the sample is poured into a clean, dried and pre-weighed pycnometer, after which it is weighed together with the sand. Then distilled water is poured into the pycnometer in such an amount that the pycnometer is filled to about 2/3 of its volume, mix the contents and put it in a slightly inclined position in a sand bath or water bath. The contents of the pycnometer are boiled for 15-20 minutes to remove air bubbles; air bubbles can also be removed by keeping the pycnometer under vacuum in a desiccator.
After removing the air, the pycnometer is wiped off, cooled to room temperature, added to the mark with distilled water and weighed. After that, the pycnometer is freed from the contents, washed, filled to the mark with distilled water and weighed again. All weighings are carried out with an error of up to 0.01 g.
8.1.5. Processing of results
(15)
where T - weight of the pycnometer with sand, g;
T 1 - mass of the empty pycnometer, g;
T 2 - mass of the pycnometer with distilled water, g;
T 3 - mass-pycnometer with sand and distilled water after removing air bubbles, g;
r in - the density of water, equal to 1 g / cm 3.
The discrepancy between the results of two determinations of the true density should not be more than 0.02 g / cm 3. In cases of large discrepancies, a third determination is carried out and the arithmetic mean of the two nearest values is calculated.
Notes:
1. When testing by the specified method of sand, consisting of grains of porous sedimentary rocks, they are preliminarily ground in a cast-iron or porcelain mortar to coarseness less than 0.16 mm and then the determination is carried out in the sequence described above.
2.It is allowed, instead of weighing the pycnometer with distilled water in the process of each test, to determine once the capacity of the pycnometer and use its value for all tests. In this case, the determination of the capacity of the pycnometer and all tests are carried out at a steady-state temperature (20 ± 1) ° C. The capacity of the pycnometer is determined by the mass of distilled water in the pycnometer, the density of which is taken to be 1.0 g / cm 3. In this case, the true density of the sand is calculated by the formula
(16)
where V - pycnometer volume, ml.
The rest of the notation is by formula (15).
8.2. Accelerated determination of true density
8.2.1. The essence of the method
The true density is determined by measuring the mass per unit volume of dried sand grains using a Le Chatelier apparatus.
8.2.2. Equipment
Le Chatelier's device (Fig. 4).
Scales in accordance with GOST 24104-88.
Weighing glass or porcelain cup in accordance with GOST 9147-80.
Desiccator in accordance with GOST 25336-82.
Drying cabinet.
Sieve with round holes 5 mm.
Sulfuric acid in accordance with GOST 2184-77.
Calcium chloride (calcium chloride) in accordance with GOST 450-77.
(Modified edition, Amendment No. 2).
Le Chatelier device
8.2.3. Test preparation
About 200 g of sand is taken from an analytical sample, sieved through a sieve with holes 5 mm in diameter, poured into a weighing glass or a porcelain cup, dried to a constant mass and cooled to room temperature in a desiccator with over-concentrated sulfuric acid or over anhydrous calcium chloride. Thereafter, two weighed portions of 75 g each are weighed.
8.2.4. Testing
The device is filled with water at the bottom zero risks, and the water level is determined by the lower meniscus. Each weighed portion of sand is poured through the funnel of the device in small uniform portions until the liquid level in the device, determined by the lower meniscus, does not rise to the marks with a division of 20 ml (or other division within the upper graduated part of the device).
To remove air bubbles, the device is rotated several times around its vertical axis.
The rest of the sand not included in the device is weighed, all weighing is carried out with an error of up to 0.01 g.
8.2.5. Processing of results
The true density of sand (r) in g / cm 3 is calculated by the formula
where T - weight of a sample of sand, g;
T 1 - the mass of the remainder of the sand, g;
V - volume of water displaced by sand, ml.
The discrepancy between the results of two determinations of the true density should not be more than 0.02 g / cm 3. In cases of large discrepancies, a third determination is made and the arithmetic mean of the two nearest values is calculated.
9. DETERMINATION OF BULK DENSITY AND VOIDITY
9.1. Determination of bulk density
9.1.1. The essence of the method
Bulk density is determined by weighing sand in measuring vessels.
9.1.2. Equipment
Scales in accordance with GOST 24104-88 or platform scales.
Measuring cylindrical metal vessels with a capacity of 1 liter (diameter and height 108 mm) and a capacity of 10 liters (diameter and height 234 mm).
Drying cabinet.
Metal ruler in accordance with GOST 427-75.
Sieve with round holes 5 mm in diameter.
(Modified edition, Amendment No. 2).
9.1.3. Test preparation
9.1.3.1. When determining the bulk density in a standard unconsolidated state during the incoming control, tests are carried out in a measuring cylindrical vessel with a capacity of 1 liter, using about 5 kg of sand, dried to constant weight and sifted through a sieve with round holes 5 mm in diameter.
9.1.3.2. When determining the bulk density of sand in a batch to convert the amount of supplied sand from mass units to volumetric units at. acceptance control tests are carried out in a measuring cylindrical vessel with a capacity of 10 liters. The sand is tested in a state of natural moisture without sieving through a sieve with holes of 5 mm diameter.
9.1.4. Testing
9.1.4.1. When determining the bulk density of sand in a standard unconsolidated state, sand is poured into a pre-weighed measuring cylinder from a height of 10 cm from the top edge until a cone is formed above the top of the cylinder. The cone without compaction is gritted flush with the edges of the vessel with a metal ruler, after which the vessel is weighed with a spice.
9.1.4.2. When determining the bulk density of sand in a batch, to convert the amount of supplied sand from mass units to volume units, sand is poured with a scoop into a pre-weighed measuring cylinder from a height of 100 cm from the upper edge of the cylinder of additional formation above the top of the cylinder of the cone. The cone without compaction of sand is removed flush with the edges of the vessel with a metal ruler, after which the vessel with sand is weighed.
9.1.5. Processing of results
The bulk density of sand (r n) in kg / m 3 is calculated by the formula
where T - weight of the measuring vessel, kg;
T 1 - mass of a measuring vessel with a special substance, kg;
V - vessel volume, m 3.
The determination of the bulk density of the sand is carried out twice, each time taking a new portion of the sand.
Note. The bulk density of the sand-gravel mixture is determined according to GOST 8269-87.
9.2. Definition of voidness
The voidness (volume of intergranular voids) of sand in a standard unconsolidated state is determined on the basis of the values of the true density and bulk density of the sand, pre-established according to paragraphs. 8 and 9.1.
The voidness of the sand ( V m.p) as a percentage by volume is calculated by the formula
(19)
where r- true density of sand, g / cm 3;
r n - bulk density of sand, kg / m 3.
10. DETERMINATION OF MOISTURE
10.1. The essence of the method
The moisture content is determined by comparing the mass of the sand in the state of natural moisture and after drying.
10.2. Equipment
Scales in accordance with GOST 24104-88.
Drying cabinet.
Baking tray.
(Modified edition, Amendment No. 2).
10.3. Testing
A sample weighing 1000 g of sand is poured into a baking sheet and immediately weighed, and then dried in the same tray to constant weight.
10.4. Processing of results
Sand moisture ( W) as a percentage is calculated by the formula
(20)
where T - the weight of the sample in a state of natural moisture;
T 1 - dry sample weight, g.
11. DETERMINATION OF REACTIVITY
The test is carried out in accordance with GOST 8269-87, using a sample of sand weighing at least 250 g.
12. DETERMINATION OF THE CONTENT OF SULPHATE AND SULFIDE COMPOUNDS
12.1. To determine the content of harmful sulfur-containing impurities in the sand, find the total sulfur content, then the content of sulphate sulfur, and from their difference calculate the content of sulphide sulfur.
If the sand contains only sulfate compounds, the total sulfur content is not determined.
12.2. Determination of total sulfur content
12.2.1. Weight method
12.2.1.1. The essence of the method
The weighting method is based on the decomposition of a sample with a mixture of nitric and hydrochloric acids, followed by the precipitation of sulfur in the form of barium sulfate and the determination of the mass of the latter.
12.2.1.2.Equipment, reagents and solutions
A muffle furnace providing a heating temperature of 900 ° C.
Porcelain cups with a diameter of 15 cm in accordance with GOST 9147-80.
Glass glasses with a capacity of 100, 200 300 400 ml in accordance with GOST 23932-90.
Porcelain crucibles in accordance with GOST 9147-80.
Desiccator in accordance with GOST 25336-82.
Bath water.
Calcium chloride (calcium chloride) in accordance with GOST 450-77, calcined at a temperature of 700-800 ° C.
Ash paper filters according to TU 6-09-1706-82.
Nitric acid in accordance with GOST 4461-77.
Hydrochloric acid in accordance with GOST 3118-77.
Ammonia water according to GOST 3760-79, 10% solution.
Barium chloride (barium chloride) according to GOST 4108-72, 10% solution.
Methyl orange according to TU6-09-5169-84, 0.1% solution.
Silver nitrate (silver nitrate) in accordance with GOST 1277-75, 1% solution.
Woven wire sieves with square cells No. 005 and 0071 in accordance with GOST6613-86.
(Modified edition, Amendment No. 2).
12.2.1.3.Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter and 100 g of sand is taken from the sieved part, which is crushed to a particle size passing through a sieve with a mesh No. 016, a sample weighing 50 g is taken from the resulting sand. sieve No. 0071.
The crushed sand is dried to constant weight, placed in a weighing bottle, stored in a desiccator with over-calcined calcium chloride and weighed portions are taken from it for analysis ( T) weighing 0.5-2 g.
12.2.1.4.Analysis
A weighed sample, weighed with a density of 0.0002 g, is placed in a glass beaker with a capacity of 200 ml or a porcelain cup, moistened with a few drops of distilled water, add 30 ml of nitric acid, cover with glass and leave for 10-15 minutes After the end of the reaction add 10 ml of hydrochloric acid, stir with a glass stick, cover with glass and put a glass or a cup in a water bath. In 20-30 minutes after the cessation of the evolution of brown vapors of nitrogen oxides, the glass is removed and the contents of the glass or cup are evaporated to dryness. After cooling, the residue is moistened with 5-7 ml of hydrochloric acid and again evaporated to dryness. The operation is repeated 2-3 times, 50 ml of hot water is added and boiled until the salts are completely dissolved.
To precipitate the elements of the group of sesquioxides, 2-3 drops of methyl orange indicator are added to the solution and the ammonia solution is added until the color of the solution changes from red to yellow and the smell of ammonia appears. After 10 minutes, the coagulated precipitate of sesqui-oxides is filtered through a "red ribbon" filter into a beaker with a capacity of 300-400 ml. The precipitate is washed with warm water with the addition of a few drops of ammonia solution. Hydrochloric acid is added to the filtrate until the color of the solution turns pink, and another 2.5 ml of acid is added.
The filtrate is diluted with water to a volume of 200-250 ml, heated to boiling, 10 ml of a hot solution of barium chloride is poured into it at one time, stirred, the solution is boiled for 5-10 minutes and left for at least 2 hours. The precipitate is filtered through a dense "blue tape" filter and washed 10 times with small portions of cold water until chloride ions are removed.
After cooling in a desiccator, the crucible with the sediment is weighed. The calcination is repeated until a constant mass is obtained. To determine the sulfur content in the reagents used for the analysis, a "blind experiment" is carried out in parallel with the analysis. The amount of sulphate barium found by "deaf experience" T 2, subtracted from the mass of barium sulfate T 1 obtained by analyzing the sample.
Note. The expression "blind experience" means that the test is carried out in the absence of the object under study, using the same reagents and observing all the conditions of the experiment.
12.2.1.5.Processing of results
(21)
where T - sample weight, g;
T 1 - weight of barium sulfate sediment, g;
T 2 - mass of barium sulfate sediment in the "blind experiment", g;
0.343 - coefficient of conversion of barium sulfate to SO 3.
Allowable discrepancies between the results of two parallel analyzes at confidence level R= 0.95 should not exceed the values specified in table. 4. Otherwise, the analysis should be repeated to obtain an acceptable discrepancy.
Table4
| Permissible discrepancy, abs. % |
|
| St. 0.5 to 1.0 | |
12.2.2. Iodometric titration method
12.2.2.1. The essence of the method
The method is based on combustion of a sample of carbon dioxide at a temperature of 1300-1350 ° C, absorption of the released SO 2 with iodine solution and titration of excess iodine with a solution of thiosulfate sodium, which did not enter into the reaction with the formed sulfuric acid.
12.2.2.2.Equipment, reagents and solutions
Installation for determination of sulfur content (Fig. 5).
Sodium thiosulfate according to GOST 27068-86, 0.005 N. solution.
Sodium carbonate (sodium carbonate) according to GOST 83-79.
Potassium dichromate (potassium dichromate) in accordance with GOST 4220-75, fixed channel.
Soluble starch according to GOST 10163-76, 1.0% solution.
Iodine in accordance with GOST 4159-79, 0.005 per solution.
Potassium iodide (potassium iodide) in accordance with GOST 4232-74.
Sulfuric acid according to GOST 4204-77, 0.1 n solution.
Analytical balance, measurement error 0.0002 g.
12.2.2.3.Preparation of 0.005 N sodium thiosulfate solution
To prepare sodium ratiosulfate solution, dissolve 1.25 g of Na 2 S 2 O 3 · 5 H 2 O in 1 l of freshly boiled distilled water and add 0.1 g of sodium carbonate. The solution is stirred and left for 10-12 days, after which its titer is determined by 0.01 N solution of potassium chromate prepared from the fixed channel.
To 10 ml of 0.01 N solution of potassium bichromate add 50 ml of 0.1 N solution of sulfuric acid, 2 g of dry potassium iodide and titrate with the prepared solution of sodium thiosulfate of pre-straw yellow color. Add a few drops of 1% starch solution (the solution turns blue) and titrate until the solution becomes discolored. The correction factor to the titer of 0.005 N sodium thiosulfate solution is determined by the formula
(22)
where is the normality of the potassium dichromate solution;
10 - the volume of 0.01 n solution of potassium bichromate taken for titration, ml;
V - volume of 0.005 n sodium thiosulfate solution consumed for titration of 10 ml 0.01 n potassium dichromate solution, ml;
Normality of sodium ratiosulfate solution.
The titer is checked at least once every 10 days.
The sodium thiosulfate solution is stored in dark bottles.
12.2.2.4.Preparation of 0.005 N iodine solution
To prepare a solution of iodine, 0.63 g of crystalline iodine and 10 g of potassium iodide are dissolved in 15 ml of distilled water. The solution is transferred into a 1 L volumetric flask with a well-ground stopper, filled up to the mark with water, mixed and stored in the dark.
The titer of the prepared iodine solution is determined by the titrated solution of sodium thiosulfate prepared by the method described above (p. 12.2.2.3).
10 ml of 0.005 N iodine solution is titrated with 0.005 N sodium thiosulfate solution in the presence of starch.
The correction factor to the titer of 0.005 n iodine solution () is determined by the formula
(23)
where is the volume of 0.005 n sodium thiosulfate solution consumed for titration of iodine solution, ml;
Correction factor 0.005 to sodium thiosulfate solution;
- the normality of the iodine solution;
10 - the amount of sodium solution taken for titration, ml.
12.2.2.5. Test preparation
Test portions are prepared according to clause 12.1.1.3, while the weight of the portions is taken equal to 0.1-1.0 g.
Before starting work, the furnace is heated to a temperature of 1300 ° C and the tightness of the installation is checked. To do this, close the valve in front of the absorption vessel and let the carbon dioxide in. The cessation of the passage of gas bubbles through the flushing bottle indicates the tightness of the installation.
Determine the coefficient TO, establishing the ratio between the concentrations of iodine solution and sodium thiosulfate. Carbon dioxide is passed through the installation for 3-5 minutes, the absorption vessel is filled 2/3 with water. 10 ml of a titrated solution of iodine is poured from the burette, 5 ml of a 1.0% starch solution is added and titrated with a solution of sodium thiosulfate until the solution is discolored. The ratio of the concentration of solutions of iodine and sodium thiosulfate TO take equal to the average of the three definitions. Concentration ratio ratio TO in laboratory conditions determined daily before testing.
12.2.2.6. Testing
A weighed sample, weighed up to 0.0002 g, is placed in a pre-calcined boat. The absorption vessel is filled with 250-300 ml of distilled water, the volume of iodine solution measured by the burette, 5 ml of starch solution is added and stirred with a stream of carbon dioxide.
Installation diagram for determining the sulfur content
1 - carbon dioxide cylinder; 2 - wash bottle with 5% copper sulfate solution; 3- wash bottle with 5% potassium permanganate solution; 4 - block with calcined calcium chloride; 5 - rubber plugs; 6 - an electric tube furnace with silicite rods, providing a heating temperature of 1300 ° C; 7 - a porcelain tube for calcining, length 70-75 mm, inner diameter 18-20 mm; 8 - porcelain boat No. 1 (length 70, width 9, height 7-5 mm) or porcelain boat No. 2 (length 95, width 12, height 10 mm) in accordance with GOST 9147-80; 9 - tap; 10 - absorption vessel; II- burette with iodine solution; I2 - burette with sodium thiosulfate solution
Note. All parts of the unit are butt-connected with rubber pipes. To prevent burning of the rubber stoppers, the inner end surface is covered with asbestos gaskets.
A boat with a hinge plate using a hook made of heat-resistant wire is placed in a heated tube (from the carbon dioxide supply side). Close the tube with a stopper and supply carbon dioxide (speed 90-100 bubbles per minute). The weighed portion is calcined for 10-15 minutes, making sure that the solution in the absorption vessel retains a blue color. Then the solution in the absorption vessel is titrated with a solution of sodium thiosulfate after decolorization. After the end of the titration, remove the boat from the oven, taking care not to contaminate the walls of the porcelain tube with the rest of the sample.
A new portion of water, a solution of iodine and starch is poured into the absorption vessel, washed with water.
12.2.2.7. Processing of results
(24)
where V - volume of iodine solution taken for titration, ml;
V 1 - volume of sodium thiosulfate solution consumed for titration of unreacted iodine excess, ml;
TO - the ratio of the concentration of iodine solution and sodium thiosulfate;
2.5 is the conversion factor for SO 3;
T - sample weight, g;
The titer of 0.005 N solution of iodine gray, g / ml, determined by the formula
where 0.1263 is the coefficient of conversion of the mass of iodine to the equivalent mass of sulfur;
The titer of 0.005 N iodine solution in sodium thiosulfate solution, g / ml, determined by the formula
(26)
where is the correction factor of 0.005 n sodium thiosulfate solution;
Normality of sodium ratiosulfate solution;
A - volume of 0.005 n sodium thiosulfate solution consumed for titration of iodine solution, ml;
126.92 - 1 g-equiv of iodine, g;
10 - the volume of 0.005 n solution of sodium taken for titration, ml;
1000 - volume of sodium thiosulfate solution, ml.
Allowable discrepancies between the results of two parallel determinations at confidence level R= 0.95 should not exceed the values specified in table. 3. Otherwise, the experiment should be repeated to obtain an acceptable discrepancy.
12.3. Determination of sulfate sulfur content
12.3.1. The essence of the method
The method is based on the decomposition of a weight with hydrochloric acid, followed by the precipitation of sulfur in the form of barium sulfate and the determination of the mass of the latter.
12.3.2 Apparatus, reagents and solutions
For the analysis, use the apparatus, the reagents in the solutions specified in clause 12.2.1.2, while using hydrochloric acid according to GOST 3118-77, solution 1: 3 (one volumetric part of concentrated hydrochloric acid and three volumetric parts of water).
12.3.3. Test preparation
The test portion is prepared according to clause 12.1.1.3, while the weight of the sample is taken equal to 1 g.
12.3.4. Testing
Hinge T placed in a glass with a capacity of 100-150 ml, cover with glass and add 40-50 ml of hydrochloric acid. After the release of bubbles has ceased, the glass is put on the hotplate and kept at a low boil for 10-15 minutes. Sesquioxides are precipitated by adding 2-3 drops of methyl orange indicator and ammonia solution until the indicator color changes from red to yellow and the smell of ammonia appears. After 10 minutes, the precipitate is filtered off. The precipitate is washed with warm water with the addition of a few drops of ammonia solution.
The filtrate is neutralized with hydrochloric acid until the color of the solution turns pink and another 2.5 ml of acid is added. The solution is heated to a boil and 10 ml of a hot solution of barium chloride is added in one step, stirred, the solution is boiled for 5-10 minutes and left for at least 2 hours. The precipitate is filtered through a dense filter "blue ribbon" and washed 10 times with small portions of cold water until the chloride -ions.
The completeness of the removal of chloride ions is checked by the reaction with silver nitrate: a few drops of the filtrate are placed on glass and a drop of a 1% solution of silver nitrate is added. The absence of the formation of a white precipitate indicates the complete removal of chloride ions.
A precipitate with a filter is placed in a porcelain crucible, pre-calcined to constant weight at a temperature of 800-850 ° C, dried, incinerated, avoiding ignition of the filter, and calcined in an open crucible until the filter is completely burned out, and then at a temperature of 800-850 ° C for 30-40 minutes
After cooling in a desiccator, the crucible with the sediment is weighed. The calcination is repeated until a constant mass is obtained.
In parallel with the analysis, a "dumb test" is carried out (see the note to clause 12.2.1.4). Amount of barium sulfate T 2 found by "deaf experience" is subtracted from the mass of barium sulfate T 1 obtained from the analysis of the sample.
12.3.5. Processing of results
Acceptable discrepancies between the results of two parallel analyzes are taken in accordance with clause 12.2.1.5.
12.4. Determination of sulfide sulfur content
where NS - total sulfur content in terms of SO 3,%;
X 1 - the content of sulfate sulfur in terms of SO 3,%.
13. DETERMINATION OF FROST RESISTANCE OF SAND FROM CRUSHING
13.1. The essence of the method
The frost resistance of sand is determined by the loss of mass during successive freezing and thawing.
13.2. Equipment
Freezer chamber.
Drying cabinet.
Scales in accordance with GOST 24104-88.
Sieves with meshes No. 1.25; 016 according to GOST6613-86 and with round holes 5 mm in diameter.
A vessel for thawing samples.
Cloth bags made of dense fabric with double walls.
Trays.
(Modified edition, Amendment No. 2).
13.3.Sample preparation
The laboratory sample is reduced to a mass of not less than 1000 g, sieved on two sieves: the first with holes 5 mm in diameter and the second with a mesh No. 1.25 or 016, depending on the size of the test material, dried to constant weight, after which two samples weighing 400 g are taken ...
13.4.Testing
Each weighed portion is placed with an intervention that ensures the safety of the grains, immersed in a vessel with water to saturate for 48 hours.
Samples in a chamber at a steady-state temperature of minus (20 ± 5) ° С are kept for 4 hours, after which the bags with weighed portions are removed, immersed in a vessel with water, having a temperature of 20 ° С, and kept for 2 hours.
After carrying out the required number of freezing and thawing cycles, a sample from the bag is poured onto a control sieve with a mesh No. 1.25 or 016, carefully washing off the remaining grains from the walls of the bag. The weighed portion, which is on the control sieve, is washed, and the remainder is dried to constant weight.
13.5. Processing of results
Weight loss of the sample ( NS mrz) as a percentage is calculated by the formula
(28)
where T - sample weight before testing, g;
T 1 - weight of grains weighed on a control sieve with mesh No. 1.25 or 016 after testing, g.
14. DETERMINATION OF CLAY PARTICLES CONTENT BY SWELLING IN SAND FOR ROAD CONSTRUCTION
14.1.The essence of the method
The essence of the method consists in determining the value of the increment in the volume of clay particles in the course of not less than 24 hours from the moment of settling and calculating the content of clay particles in the average value of the increment in volume.
The method extends to natural sands and sands from screenings of crushing rocks, from slags of ferrous and nonferrous metallurgy and phosphorus slags used for road construction.
14.2.Controls and accessories
Drying cabinet providing heating temperature (105 ± 5) ° С.
General purpose laboratory scales of the 4th accuracy class in accordance with GOST 24104-88.
Sieve with 5 mm holes; sieves with meshes No. 063 and No. 016 in accordance with GOST6613-86.
Measuring glass cylinders with a capacity of 50 or 100 ml in accordance with GOST 1770-74 - 2 pcs.
Funnel in accordance with GOST 1770-74 - 2 pcs.
Glass stick with rubber tip - 2 pcs.
Calcium chloride technical in accordance with GOST 450, 5% solution.
14.3.Test procedure
From an average sample of sand weighing 1 kg, dried to constant weight at a temperature of (105 ± 5) ° С and sieved through a sieve with holes of 5 mm, a sample weighing 200 g is taken. Natural sand and sand from crushing screenings of rocks are sieved through a sieve with a mesh No. 016 , sand from slags of ferrous and non-ferrous metallurgy and phosphorus slags - through a sieve with a mesh No. 063. Determine the content of grains smaller than 0.16 mm D 016 and less than 0.63 mm D 063 respectively. The sand passing through the sieve is poured in equal portions through a funnel into two glass measuring cylinders by tapping on the cylinders until the volume of sand in the compacted state reaches the 10 ml mark. Then the sand in each cylinder is loosened, 30-50 ml of distilled water is poured in, thoroughly mixed with a glass stick with a rubber tip until the smear clay on the cylinder walls disappears completely. After that, 5 ml of a 5% solution of calcium chloride is coagulated into each cylinder as a coagulant, thoroughly mixed and distilled water to a mark of 50 or 100 ml on a glass rod (to wash off clay from it). After settling for at least 24 hours, but not more than 30 hours, measure the volume occupied by the sand.
14.4.Processing of test results
Volume increment K when clay particles swell for each 1 ml of the initial volume, calculate to the second decimal place according to the formula
where is the initial volume of sand, ml;
Sand volume after swelling, ml
The swelling increment is defined as the arithmetic mean of the two results.
By value K(table 6) determine the content of clay particles in sand grains with a size of less than 0.16 mm ( A 0.16) for natural sand and sand from screenings of crushing rocks and less than 0.63 mm ( A 0.63) for sand from ferrous and non-ferrous metallurgy and phosphorus slags.
(30)
(Introduced additionally. Amendment No. 2).
APPLICATION
Reference
SCOPE OF TESTING
The name and scope of the tests are shown in table. 5.
| Test name | Application area |
|||
| Quality control at the manufacturer | Geological exploration | Incoming control at the consumer enterprise |
||
| acceptance | periodic |
|||
| 1. Determination of grain size composition and size modulus | ||||
| 2. Determination of the content of clay in lumps | ||||
| 3. Determination of the content of dust and clay particles | ||||
| 4. Determination of the presence of organic impurities | ||||
| 5. Determination of the mineralogical and petrographic composition | ||||
| 6. Determination of true density | ||||
| 7. Determination of bulk density and voidness | ||||
| 8. Determination of moisture | ||||
| 9. Determination of reactivity | ||||
| 10. Determination of the content of sulfate and sulfide compounds | ||||
| 11. Determination of frost resistance of sand from crushing screenings |
Note. The "+" sign means that the test is being carried out;
sign "-" - do not carry out,
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the USSR Ministry of Construction Materials Industry
CONTRACTORS
M. L. Nisnevich, Dr. Tech. Sciences (topic leader); N. S. Levkova, Cand. tech. sciences; E. I. Levina, Cand. tech. sciences; G. S. Zarzhitsky, Cand. tech. sciences; L. I. Levin; V. N. Tarasova, Cand. tech. sciences; A. I. Polyakova; E. A. Antonov; L.V. Bereznitsky, Cand. tech. sciences; I.I. Kurbatova Cand. tech. sciences; G. P. Abysova; MF Semizorov; T. A. Kochneva; A. V. Strelskiy; V. I. Novatorov; V.A. Theological; T. A. Fironova
2. APPROVED AND PUT INTO EFFECT by the Decree of the State Construction Committee of the USSR dated 05.10.88 No. 203
3. Complies with ST SEV 5446-85, ST SEV 6317-88 (in terms of sampling and determination of grain size composition)
4. Instead of GOST 8735-75 and GOST 25589-83
5. REFERENCE REFERENCE DOCUMENTS
| Item number, sub-item |
|
| GOST 8.326-78 | |
| 8.1.2; 8.2.2; 12.2.1.2 |
|
| GOST 1277-75 | |
| GOST 1770-74 | |
| GOST 2184-77 | |
| GOST 2874-82 | |
| GOST 3118-77 | 12.2.1.2; 12.3.2 |
| GOST 3760-79 | |
| GOST 4108-72 | |
| GOST 4159-79 | |
| GOST 4204-77 | |
| GOST 4220-75 | |
| GOST 4232-74 | |
| GOST 4328-77 | |
| GOST 4461-77 | |
| GOST 5072-79 | |
| GOST 6613-86 | 1.6, 3.2, 4.2, 5.2.2, 7.2, 12.2.1.2, 13.2 |
| GOST 6709-72 | |
| GOST 8269.0-97 | 2.3, 5.3.1, 5.4.1, 9.1.5, 11, 12.2.1.3 |
| GOST 8284-78 | |
| GOST 8736-85 | |
| GOST 9147-80 | 5.2.2, 8.2.2, 12.2.1.2, 12.2.2.4 |
| GOST 10163-76 | |
| GOST 22524-77 | |
| GOST 23732-79 | |
| GOST 23932-79 | |
| GOST 24104-88 | 3.2, 4.2, 5.1.2, 5.2.2, 6.2, 7.2, 8.1.2, 8.2.2, 9.1.2, 10.2, 13.2 |
| GOST 25336-82 | 8.1.2, 8.2.2, 12.2.1.2 |
| GOST 25706-83 | |
| GOST 27068-86 | |
| TU 6-09-1706-82 | |
| TU 6-09-5169-84 |
6. REPUBLICATION (November 1997) with Amendment No. 1, approved in June 1989 (IUS 11-89)
| 1. General Provisions. 1 2. Sampling. 2 3. Determination of grain size composition and size modulus. 3 4. Determination of the content of clay in lumps. 5 5. Determination of the content of dust and clay particles. 5 5.1. Elimination method. 5 5.2. Pipette method. 7 5.3. Wet sieving method. eight 5.4. Photoelectric method. eight 6. Determination of the presence of organic impurities. eight 7. Determination of the mineralogical and petrographic composition. nine 8. Determination of the true density. ten 8.1. Pycnometric method. ten 8.2. Accelerated determination of true density. eleven 9. Determination of bulk density and voidness. 13 9.1. Determination of bulk density. 13 9.2. Definition of voidness. 13 10. Determination of moisture content. fourteen 11. Determination of reactivity. fourteen 12. Determination of the content of sulfate and sulfide compounds. fourteen 13. Determination of frost resistance of sand from crushing screenings. 19 14. Determination of the content of clay particles by the method of swelling in sand for road construction. twenty Application Scope of tests. 21 |
GOST 8735-88
(ST SEV 5446 ¾ 85)
ST SEV 6317 ¾ 88
UDC 691.223.001.4.006.354 Group Ж19
STATE STANDARD OF THE UNION OF SSR
SAND FOR CONSTRUCTION WORKS
Test methods
Sand for construction work.
Testing methods
OKSTU 5711
Date of introduction 01.07.89
Failure to comply with the standard is punishable by law
This standard applies to sand used as aggregate for concrete in monolithic, precast concrete and reinforced concrete structures, as well as material for the corresponding types of construction work, and specifies test methods.
1. GENERAL PROVISIONS
1.1. The scope of the sand test methods specified in this standard is indicated in the appendix.
1.2. Samples are weighed to an accuracy of 0.1% by weight, unless otherwise specified in the standard.
1.3. Samples or weighed portions of sand are dried to constant weight in a drying oven at a temperature of (105 ± 5) ° From until the difference between the results of two weighings is no more than 0.1% of the mass. Each subsequent weighing is carried out after drying for at least 1 hour and cooling for at least 45 minutes.
1.4. The test results are calculated to the second decimal place, unless other instructions are given regarding the accuracy of the calculation.
1.5. The test result is taken as the arithmetic mean of the parallel determinations provided for the corresponding method.
1.6. The standard set of sand screens includes 10 round-hole screens; 5 and 2.5 mm and wire sieves with standard square meshes No. 1.25; 063; 0315; 016; 005 in accordance with GOST 6613 (sieve frames are round or square with a diameter or side side of at least 100 mm).
Note. The use of sieves with nets No. 014 is allowed before equipping enterprises with sieves with nets No. 016.
1.7. The temperature of the room in which the tests are carried out shall be (25 ± 10) ° C. Before starting the test, sand and water should be at a temperature corresponding to the temperature of the air in the room.
1.8. Water for testing is used in accordance with GOST 2874 or GOST 23732, if the standard does not provide instructions on the use of distilled water.
1.9. When using hazardous (caustic, toxic) substances as reagents, one should be guided by the safety requirements set forth in the regulatory and technical documents for these reagents.
1.10. The "Hardware" sections provide links to national standards. The use of similar imported equipment is allowed. The non-standard measuring instruments used, specified in the "Equipment" section, must undergo metrological certification in accordance with GOST 8.326.
2. SAMPLING
2.1. During acceptance control at the manufacturing plant, spot samples are taken, from which, by mixing, one combined sample is obtained from the replaceable product of each technological line.
2.2. Sampling of point samples from technological lines transporting products to a warehouse or directly to vehicles is carried out by crossing the material flow on a belt conveyor or at points of a material flow difference using samplers or manually.
To check the quality of sand shipped directly to the open pit face, spot samples are taken during loading into vehicles.
2.3. Spot samples to obtain a combined sample begin to be taken 1 hour after the start of the shift and then taken every hour during the shift.
The sampling interval for manual sampling can be increased if the manufacturer produces products of consistent quality. To establish the permissible sampling interval, the coefficient of variation of the values of the content of grains passing through a sieve with a mesh No. 016 and the content of dust and clay particles is determined on a quarterly basis. To determine the coefficient of variation of these indicators during the shift, every 15 minutes, spot samples with a mass of at least 2000 are taken. For each spot sample, the content of grains passing through a sieve with a mesh No. 016, and the content of dust and clay particles are determined. Then the coefficients of variation of these indicators are calculated in accordance with GOST 8269.
Depending on the obtained maximum value of the coefficient of variation for the two determined indicators, the following intervals for taking spot samples during the shift are taken:
3 hours - with a coefficient of variation of the indicator up to 10%;
2 h ”” ”” ”15%.
2.4. The mass of a spot sample with a sampling interval of 1 hour should be at least 1500 g. When increasing the sampling interval in accordance with clause 2.3, the mass of a selected spot sample should be doubled at an interval of 2 hours, at an interval of 3 hours - four times.
If, when taking samples with a sampler, the mass of the spot sample turns out to be less than the specified one by more than 100 g, then it is necessary to increase the number of samples taken to ensure that the mass of the combined sample is at least 10,000 g.
2.5. The pooled sample is mixed and cut by quartering or using a fluted divider to obtain a laboratory sample prior to shipment to the laboratory.
To quarter the sample (after mixing it), the material cone is leveled and divided into four parts by mutually perpendicular lines passing through the center. Any two opposite quarters are sampled. By successive quartering, reduce the sample by two, four times, etc., until a sample with a mass corresponding to clause 2.6 is obtained.
2.6. The mass of a laboratory sample during acceptance control at the manufacturer must be at least 5000 g, it is used for all tests provided for during acceptance control.
When conducting periodic tests, as well as during incoming control and when determining the properties of sand during geological exploration, the mass of the laboratory sample must ensure that all tests provided for by the standard are carried out. It is allowed to carry out several tests using one sample, if the determined properties of the sand do not change during the tests, and the mass of the laboratory sample must be at least twice the total mass required for the tests.
2.7. An analytical sample is taken from the laboratory sample for each test.
Samples are taken from the analytical sample in accordance with the test procedure.
2.8. For each laboratory sample intended for periodic testing in the central laboratory of the association or in a specialized laboratory, as well as for arbitration tests, a sampling report is drawn up, including the name and designation of the material, the place and date of sampling, the name of the manufacturer, the designation of the sample and the signature of the responsible for taking a sample of the face.
Selected samples are packed in such a way that the mass and properties of the materials do not change prior to testing.
Each sample is provided with two labels with the sample designation. One label is placed inside the package, the other in a prominent place on the package.
During transportation, the packaging must be protected from mechanical damage and moisture.
2.9. To check the quality of sand extracted and laid by hydromechanization, the reclamation map is divided in plan along the length (along the alluvium map) into three parts.
Point samples are taken from each part from at least five different locations (in plan). To take a spot sample, a hole is dug with a depth of 0.2-0.4 m. A sample of sand is taken from the hole with a scoop, moving it from bottom to top along the wall of the hole.
A combined sample is obtained from the spot samples by mixing, which is reduced to obtain a laboratory sample according to clause 2.5.
The quality of the sand is assessed separately for each part of the reclamation map according to the results of testing a sample taken from it.
2.10. In the arbitration check of the quality of sand in warehouses, spot samples are taken with a scoop in places located evenly over the entire surface of the warehouse, from the bottom of dug holes with a depth of 0.2-0.4 m. The holes should be staggered. The distance between the holes should not exceed 10 m. The laboratory sample is prepared according to clause 2.5.
2.11. During the incoming inspection at the consumer enterprise, a combined sample of sand is taken from the tested batch of material in accordance with the requirements of GOST 8736. A laboratory sample is prepared in accordance with clause 2.5.
2.12. During geological exploration, samples are taken in accordance with the normative and technical documentation approved in the prescribed manner.
3. DETERMINATION OF GRAIN COMPOSITION AND COARSE MODULE
3.1. The essence of the method
The grain size distribution is determined by sieving the sand on a standard set of sieves.
3.2. Equipment
A set of sieves in accordance with GOST 6613 and sieves with round holes with a diameter of 10; 5 and 2.5 mm.
Drying cabinet.
3.3. Test preparation
An analytical sample of sand weighing at least 2000 g is dried to constant weight.
3.4. Testing
A sample of sand dried to constant weight is sieved through sieves with round holes 10 and 5 mm in diameter.
Residues on sieves are weighed and the content of gravel fractions with a grain size of 5 to 10 mm ( Gr 5) and St. 10 mm ( Gr 10) in percentage by weight according to the formulas:
(1)
(2)
Where M 10 - residue on a sieve with round holes with a diameter of 10 mm, g;
M 5 - residue on a sieve with round holes 5 mm in diameter, g;
M - sample weight, g.
From a part of the sand sample that has passed through a sieve with holes 5 mm in diameter, a sample weighing at least 1000 g is taken to determine the grain size composition of the sand.
It is allowed for geological exploration to disperse the sample after preliminary flushing with the determination of the content of dust and clay particles. The content of dusty and clay particles is included when calculating the results of sieving in the mass of particles passing through a sieve with a mesh No. 016, and in the total weight of the sample. In mass tests, after washing with the determination of the content of dusty and clay particles and drying the sample to constant weight, it is allowed to sift a sample of sand (without gravel fraction) weighing 500 g.
The prepared sample of sand is sieved through a set of sieves with round holes 2.5 mm in diameter and with meshes No. 1.25; 063; 0315 and 016.
Sifting is done mechanically or manually. The duration of sieving should be such that, with control intensive manual shaking of each sieve for 1 min, no more than 0.1% of the total mass of the sieved sample passes through it. With mechanical sieving, its duration for the device used is established empirically.
With manual sieving, it is allowed to determine the end of sieving by vigorously shaking each sieve over a sheet of paper. Sifting is considered complete if there is practically no falling of sand grains.
When determining the grain size composition by the wet method, a sample of the material is placed in a vessel and filled with water. After 24 hours, the contents of the vessel are thoroughly mixed until the clay film is completely soaked onto grains or lumps of clay, poured (in portions) onto the top sieve of a standard set and sieved, rinsing the material on sieves until the wash water becomes clear. The partial residues on each sieve are dried to constant weight and cooled to room temperature, then their weight is determined by weighing.
(Modified edition, Amendment No. 1).
3.5. Processing of results
Based on the results of sifting, the following is calculated:
The partial residue on each sieve ( a i) as a percentage according to the formula
(3)
Where t i - the mass of the residue on a given sieve, g;
T - weight of the sieved sample, g;
The total residue on each sieve ( A i) as a percentage according to the formula
(4)
Where a 2,5 , a 1,25 , a i - partial residues on the respective sieves;
Sand fineness module ( M j) without grains larger than 5 mm according to the formula
(5)
Where A 2,5 , A 1,25 ,A 063 , A 0315 , A 016 - complete residues on a sieve with round holes 2.5 mm in diameter and on sieves with meshes No. 1.25; 063; 0315, 016,%.
The result of determining the grain size composition of sand is drawn up in accordance with table. 1 or depicted graphically in the form of a sieving curve in accordance with fig. 1.
Sieving curve
Heck. 1
Table 1
|
Residues,% by weight, on sieves |
Passage through |
|||||
|
Remainder name |
1,25 |
0,63 |
0,315 |
0,16 (0,14) |
Sieve with mesh № 016(014), % by weight |
|
|
Private |
a 2,5 |
a 1,25 |
a 063 |
a 0315 |
a 016(014) |
a 016(014) |
|
Full |
A 2,5 |
A 1,25 |
A 063 |
A 0315 |
A 016(014) |
|
4. DETERMINATION OF CLAY CONTENT IN LUMPS
4.1. The essence of the method
4.2. Equipment
Scales in accordance with GOST 23711 or GOST 24104.
Drying cabinet.
Sieves with mesh No. 1.25 in accordance with GOST 6613 and with round holes 5 and 2.5 mm in diameter.
The needle is steel.
4.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter, take from it at least 100 g of sand, dried to constant weight and scattered on sieves with holes with a diameter of 2.5 mm and mesh No. 1.25. From the obtained sand fractions, weighed samples are taken with a mass:
5.0 g - fraction of St. 2.5 to 5 mm;
1.0 g - fractions from 1.25 to 2.5 mm
Each weighed amount of sand is poured into a thin layer on glass or metal sheet and moistened with a pipette. Clumps of clay, differing in viscosity from sand grains, are isolated from the sample with a steel needle, using a magnifying glass if necessary. The sand grains remaining after the separation of lumps are dried to constant weight and weighed.
4.4. Processing of results
(6)
(7)
Where m 1 , m 2 - the weights of the sample of sand of the fraction, respectively, from 2.5 to 5 mm and from 1.25 to 2.5 mm before the release of clay, g;
T 1, m 3 - the mass of sand grains, fraction, respectively, from 2.5 to 5 mm and from 1.25 to 2.5 mm after the separation of clay, g.
(8)
Where a 2,5 , a 1.25 - partial residues in percent by weight on sieves with openings of 2.5 and 1.25 mm, calculated according to clause 3.5.
5. DETERMINATION OF THE CONTENT OF DUST AND CLAY PARTICLES
5.1. Elimination method
5.1.1. The essence of the method
5.1.2. Equipment
Scales in accordance with GOST 23711 or GOST 24104.
Drying cabinet.
A cylindrical bucket with a height of at least 300 mm with a siphon or a vessel for eluting sand (Fig. 2).
Stopwatch.
5.1.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter, the sand that has passed through the sieve is dried to constant weight and a sample of 1000 g is taken from it.
5.1.4. Testing
A weighed amount of sand is placed in a cylindrical bucket and filled with water so that the height of the water layer above the sand is about 200 mm. The sand filled with water is kept for 2 hours, stirring it several times, and thoroughly washed from the clay particles adhering to the grains.
Thereafter, the contents of the bucket are vigorously mixed again and left alone for 2 minutes. After 2 minutes, drain the suspension obtained during washing with a siphon, leaving its layer above the sand with a height of at least 30 mm. Then the sand is again poured with water to the above level. Washing the sand in this sequence is repeated until the water after washing remains clear.
When using an elutriation vessel, the test is carried out in the same sequence. In this case, water is poured into the vessel up to the upper drain hole, and the suspension is poured through the two lower holes.
After elutriation, the washed sample is dried to constant weight T 1 .
5.1.5. Processing of results
(9)
Where T - weight of the dried sample before elutriation, g;
m1 - the mass of the dried sample after elutriation, g.
Exhaustion vessel
Heck. 2
Notes:
1. When testing natural sands, the grains of which are densely cemented with clay, the sample is kept in water for at least 1 day.
2. It is allowed to test sand in a state of natural moisture. In this case, in a parallel sample, the moisture content of the sand and the content of dust and clay particles ( NS mark) is calculated as a percentage by the formula
(10)
Where T c - weight of the sample in a state of natural moisture, g;
T 1 - weight of the sample, dried after elutriation to constant weight, g;
W- humidity of the tested sand,%.
5.2. Pipette method
5.2.1. The essence of the method
5.2.2. Equipment
The bucket is cylindrical with two marks (belts) on the inner wall, corresponding to a capacity of 5 and 10 liters.
The bucket is cylindrical without marks.
Drying cabinet.
Sieves with mesh No. 063 and 016 in accordance with GOST 6613.
Metal cylinders with a capacity of 1000 ml with a viewing window (2 pcs.).
Metallic pipette with a volume of 50 ml (Fig. 3).
Funnel with a diameter of 150 mm.
Stopwatch.
A cup or glass for evaporation in accordance with GOST 9147.
5.2.3. Testing
A sample of sand weighing about 1000 g in a state of natural moisture is weighed, placed in a bucket (without a label) and filled with 4.5 liters of water. In addition, about 500 ml of water is prepared for subsequent rinsing of the bucket.
The sand filled with water is kept for 2 hours, stirring it several times, and thoroughly washed from the clay particles adhering to the grains. Then the contents of the bucket are poured carefully onto two sieves: the upper one with mesh No. 063 and the lower one with mesh No. 016, placed on a bucket with marks.
The suspensions are allowed to settle and the clarified water is carefully poured into the first bucket. The sand is washed again with the drained water on sieves over the second bucket (with marks). After that, the first bucket is rinsed with the water left and this water is drained into the second bucket. At the same time, such an amount of the left water is used so that the level of the suspension in the latter reaches exactly the 5 l mark; if the remaining water is not enough for this, the volume of the suspension is brought to 5 liters by adding additional water.
After that, the suspension is thoroughly mixed in a bucket and immediately filled with it using a funnel, alternately two metal cylinders with a capacity of 1000 ml, while continuing to stir the suspension. The slurry level in each cylinder must match the mark on the sight glass.
The suspension in each cylinder is stirred with a glass or metal rod or the cylinder is overturned several times, closing it with a lid for better mixing.
After the end of stirring, leave the cylinder at rest for 1.5 minutes. 5-10 s before the end of exposure, a graduated pipette with a tube closed with a finger is lowered into the cylinder so that the support cap rests on the top of the cylinder wall, while the bottom of the pipette will be at the level of suspension withdrawal - 190 mm from the surface. After the specified time (5-10 s), open the pipette tube and after filling it again close the tube with a finger, remove the pipette from the cylinder and, opening the tube, pour the contents of the pipette into a pre-weighed cup or glass. The filling of the pipette is controlled by the change in the level of the suspension in the viewing window.
Metal cylinder and volumetric pipette
1 - cylinder; 2 - pipette; 3 - label (1000 ml);
4 - slurry level in the cylinder
Heck. 3
Instead of metal cylinders with a viewing window and a special pipette, it is allowed to use ordinary glass measuring cylinders with a capacity of 1 l and a glass pipette with a capacity of 50 ml, lowering it into the cylinder to a depth of 190 mm.
The suspension in a cup (glass) is evaporated in an oven at a temperature of (105 ± 5) ° C. The cup (glass) with the evaporated powder is weighed on a balance with an error of up to 0.01 g. Similarly, a sample of the suspension is taken from the second cylinder.
5.2.4. Processing of results
(11)
Where T - weight of a sample of sand, g;
T 1 - the mass of the cup or glass for evaporation of the suspension, g;
T 2 - weight of a cup or glass with evaporated powder, g.
In the case of testing sand heavily contaminated with dusty and clay particles, the volume of water for flushing is taken equal to 10 liters instead of 5 liters. Accordingly, the volume of the suspension in the bucket with marks is increased to 10 l. In this case, the test result ( NS mark) as a percentage, calculated by the formula
(12)
Note. Sludge mass allowed ( T 2 -T 1) determine by the density of the suspension by the formula
(13)
Where T 3 - mass of the pycnometer with suspension, g;
T 4 - mass of the pycnometer with water, g;
r - the density of the sediment, g / cm 3 (taken equal to 2.65 g / cm 3).
The result of determining the mass of sediment T 2 -T 1 is introduced into formula (11).
5.3. Wet sieving method
5.3.1. The essence of the method
The test is carried out in accordance with GOST 8269, using a sample of sand weighing 1000 g and a sieve with a mesh No. 0315 and 005.
5.4. Photoelectric method
5.4.1. The essence of the method
The method is based on comparing the degree of transparency of pure water and a suspension obtained by washing the sand.
The test is carried out in accordance with GOST 8269, using a sample of sand weighing 1000 g.
5.5. The content of dust and clay particles can be determined by one of the above methods, depending on the availability of equipment. In this case, the elutriation method is allowed to be used until 01/01/95.
6. DETERMINATION OF THE PRESENCE OF ORGANIC IMPURITIES
6.1. The essence of the method
The presence of organic impurities (humic substances) is determined by comparing the color of the alkaline solution above the sample of sand with the color of the standard.
6.2. Equipment, reagents and solutions
Scales in accordance with GOST 29329 or GOST 24104.
Photocolorimeter FEK-56M or spectrophotometer SF-4, or other similar devices.
Glass cylinders with a capacity of 250 ml made of transparent colorless glass (inner diameter 36-40 mm) in accordance with GOST 1770.
Bath water.
Sodium hydroxide (sodium hydroxide) according to GOST 4328, 3% solution.
Tannin, 2% solution in 1% ethanol.
6.3. Test preparation
A sample of about 250 g is taken from an analytical sample of sand in a state of natural moisture.
Prepare a standard solution by dissolving 2.5 ml of 2% tannin solution in 97.5 ml of 3% sodium hydroxide solution. The prepared solution is stirred and left for 24 hours.
The optical density of the tannin solution, determined on a photocolorimeter or spectrophotometer in the wavelength range of 450-500 nm, should be 0.60-0.68.
6.4. Testing
The measuring cylinder is filled with sand to a level of 130 ml and it is filled with a 3% sodium hydroxide solution to a level of 200 ml. The contents of the cylinder are stirred and left for 24 hours, stirring is repeated 4 hours after the first stirring. Then compare the color of the liquid over the sample with the color of the standard solution or glass, the color of which is identical to the color of the standard solution.
Sand is suitable for use in concrete or mortar if the liquid above the sample is colorless or is much weaker than the standard solution.
When the color of the liquid is slightly lighter than the standard solution, the contents of the vessel are heated for 2-3 hours in a water bath at a temperature of 60-70 ° C and the color of the liquid above the sample is compared with the color of the standard solution.
When the color of the liquid is the same or darker than the color of the standard solution, it is necessary to test the aggregate in concrete or solutions in specialized laboratories.
7. DETERMINATION OF MINERAL AND PETROGRAPHIC COMPOSITION
7.1. The essence of the method
7.2. Equipment and reagents
Scales in accordance with GOST 29329 or GOST 24104.
A set of sieves with meshes No. 1.25; 063; 0315 and 016 in accordance with GOST 6613 and with round holes with diameters of 5 and 2.5 mm.
Drying cabinet.
Binocular microscope with magnification from 10 to 50 C , polarizing microscope with magnification up to 1350 C.
Mineralogical magnifier in accordance with GOST 25706.
A set of reagents.
The needle is steel.
7.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter, at least 500 g of sand is taken from the sieved part of the sample.
The sand is washed, dried to constant weight, scattered on a set of sieves with holes 2.5 mm in diameter and mesh No. 1.25; 063; 0315; 016 and take a sample with a mass of at least:
25.0 g - for sand with a grain size of St. 2.5 to 5.0 mm;
5.0 g ”” ”” ”St. 1.25 to 2.5 mm;
1.0 g ”” ”” ”St. 0.63 to 1.25 mm;
0.1 g ”” ”” ”st. 0.315 to 0.63 mm;
0.01 g ″ ″ ″ ″ 0.16 to 0.315 mm.
7.4. Testing
Each sample is poured into a thin layer on glass or paper and viewed with a binocular microscope or magnifying glass.
Sand grains, represented by fragments of the corresponding rocks and minerals, are divided with a thin needle into groups according to the types of rocks and types of minerals.
If necessary, the determination of rocks and minerals is clarified using chemical reagents (hydrochloric acid solution, etc.), as well as by analysis in immersion liquids using a polarizing microscope.
In the grains of sand, represented by fragments of minerals, the content of quartz, feldspar, dark-colored minerals, calcite, etc. is determined.
Sand grains, represented by rock debris, are divided according to genetic types in accordance with table. 2.
table 2
|
Genetic type of breeds |
Breed |
|
Sedimentary |
Limestone, dolomite, sandstone, flint, etc. |
|
Ejected: Intrusive |
Granite, gabbro, diorite, etc. |
|
Effusive |
Basalt, porphyrite, diabase, etc. |
|
Metamorphic |
Quartzite, crystalline schists, etc. |
In addition, grains of rocks and minerals attributed to harmful impurities are isolated in the sand.
These rocks and minerals include: containing amorphous varieties of silicon dioxide (chalcedony, opal, flint, etc.); sulfur; sulfides (pyrite, marcasite, pyrrhotite, etc.); sulfates (gypsum, anhydrite, etc.); layered silicates (micas, hydromicas, chlorites, etc.); iron oxides and hydroxides (magnetite, goethite, etc.); apatite; nepheline; phosphorite; halide compounds (halite, sylvin, etc.); zeolites; asbestos; graphite; coal; oil shale.
In the presence of minerals containing sulfur, the amount of sulfate and sulfide compounds in terms of SO 3 is determined according to clause 12.
The quantitative determination of the content of potentially reactive species of silica is carried out according to clause 11.
The same weighed portions of sand are used to determine the shape and nature of the surface of sand grains in accordance with table. 3.
Table 3
7.5. Processing of results
For each type of identified rocks and minerals, the number of grains is counted and their content is determined ( X) as a percentage in the sample according to the formula
(14)
Where n -the number of grains of a given rock or mineral;
N - the total number of grains in the test sample.
8. DETERMINATION OF TRUE DENSITY
8.1. Pycnometric method
8.1.1. The essence of the method
True density is determined by measuring the mass per unit volume of dried sand grains.
8.1.2. Equipment
Piconometer with a capacity of 100 ml in accordance with GOST 22524.
Scales in accordance with GOST 29329 or GOST 24104.
Desiccator according to GOST 25336.
Drying cabinet.
Sand bath or water bath.
Distilled water in accordance with GOST 6709.
8.1.3. Test preparation
A sample of about 30 g is taken from an analytical sample of sand, sieved through a sieve with holes 5 mm in diameter, dried to constant weight and cooled to room temperature in a desiccator over concentrated sulfuric acid or anhydrous calcium chloride. The dried sand is mixed and divided into two parts.
8.1.4. Testing
Each part of the sample is poured into a clean, dried and previously weighed pycnometer, after which it is weighed together with the sand. Then distilled water is poured into the pycnometer in such an amount that the pycnometer is filled to about 2/3 of its volume, the contents are mixed and placed in a slightly inclined position on a sand bath or water bath. The contents of the pycnometer are boiled for 15-20 minutes to remove air bubbles; air bubbles can also be removed by keeping the pycnometer under vacuum in a desiccator.
After removing the air, the pycnometer is wiped off, cooled to room temperature, added to the mark with distilled water and weighed. After that, the pycnometer is freed from the contents, washed, filled to the mark with distilled water and weighed again. All weighings are carried out with an error of up to 0.01 g.
8.1.5. Processing of results
The true density of the sand ( r
(15)
Where T - weight of the pycnometer with sand, g;
T 1 - mass of the empty pycnometer, g;
T 2 - mass of the pycnometer with distilled water, g;
T 3 - mass of the pycnometer with sand and distilled water after removing air bubbles, g;
r c - the density of water, equal to 1 g / cm 3.
The discrepancy between the results of two determinations of the true density should not be more than 0.02 g / cm 3. In cases of large discrepancies, a third determination is made and the arithmetic mean of the two nearest values is calculated.
Notes:
1. When testing by the specified method of sand, consisting of grains of porous sedimentary rocks, they are preliminarily ground in a cast-iron or porcelain mortar to a particle size of less than 0.16 mm and then the determination is carried out in the sequence described above.
2. Instead of weighing the pycnometer with distilled water during each test, it is allowed to determine once the capacity of the pycnometer and use its value for all tests. In this case, the determination of the capacity of the pycnometer and all tests are carried out at a steady temperature (20 ± 1) ° C. The capacity of the pycnometer is determined by the mass of distilled water in the pycnometer, the density of which is taken equal to 1.0 g / cm 3. In this case, the true density of the sand is calculated by the formula
(16)
Where V - pycnometer volume, ml.
The rest of the designations are according to the formula (15).
8.2. Accelerated determination of true density
8.2.1. The essence of the method
The true density is determined by measuring the mass per unit volume of dried sand grains using a Le Chatelier instrument.
8.2.2. Equipment
Le Chatelier's device (Fig. 4).
Scales in accordance with GOST 29329 or GOST 24104.
Weighing glass or porcelain cup in accordance with GOST 9147.
Desiccator according to GOST 25336.
Drying cabinet.
Sieve with round holes 5 mm.
Sulfuric acid in accordance with GOST 2184.
Calcium chloride (calcium chloride) in accordance with GOST 450.
Le Chatelier device
Heck. 4
8.2.3. Test preparation
About 200 g of sand is taken from an analytical sample, sieved through a sieve with holes 5 mm in diameter, poured into a weighing glass or porcelain cup, dried to constant weight and cooled to room temperature in a desiccator over concentrated sulfuric acid or over anhydrous calcium chloride. After that, two weighed portions of 75 g each are weighed.
8.2.4. Testing
The device is filled with water to the lower zero risk, and the water level is determined by the lower meniscus. Each weighed portion of sand is poured through the funnel of the device in small even portions until the liquid level in the device, determined by the lower meniscus, rises to the marks with a division of 20 ml (or other division within the upper graduated part of the device).
To remove air bubbles, the device is turned several times around its vertical axis.
The remainder of the sand not included in the device is weighed, all weighing is carried out with an error of up to 0.01 g.
8.2.5. Processing of results
The true density of the sand ( r ) in g / cm 3 is calculated by the formula
(17)
Where T - weight of a sample of sand, g;
T 1 - the mass of the remainder of the sand, g;
V - volume of water displaced by sand, ml.
The discrepancy between the results of two determinations of the true density should not be more than 0.02 g / cm 3. In cases of large discrepancies, a third determination is made and the arithmetic mean of the two nearest values is calculated.
9. DETERMINATION OF BULK DENSITY AND VOIDITY
9.1. Determination of bulk density
9.1.1. The essence of the method
Bulk density is determined by weighing sand in measuring vessels.
9.1.2. Equipment
Scales in accordance with GOST 29329, GOST 24104 or platform scales.
Measuring cylindrical metal vessels with a capacity of 1 liter (diameter and height 108 mm) and a capacity of 10 liters (diameter and height 234 mm).
Drying cabinet.
Metal ruler in accordance with GOST 427.
Sieve with round holes 5 mm in diameter.
9.1.3. Test preparation
9.1.3.1. When determining the bulk density in a standard unconsolidated state at the incoming control, tests are carried out in a measuring cylindrical vessel with a capacity of 1 liter, using about 5 kg of sand, dried to constant weight and sifted through a sieve with round holes 5 mm in diameter.
9.1.3.2. When determining the bulk density of sand in a batch to convert the amount of supplied sand from mass units to volume units during acceptance control, tests are carried out in a measuring cylindrical vessel with a capacity of 10 liters. The sand is tested in a state of natural moisture without sieving through a sieve with holes of 5 mm diameter.
9.1.4. Testing
9.1.4.1. When determining the bulk density of sand in a standard uncompacted state, sand is poured with a scoop into a pre-weighed measuring cylinder from a height of 10 cm from the top edge until a cone is formed above the top of the cylinder. The cone without compaction of sand is removed flush with the edges of the vessel with a metal ruler, after which the vessel with sand is weighed.
9.1.4.2. When determining the bulk density of sand in a batch, to convert the amount of supplied sand from mass units to volume units, sand is poured with a scoop into a pre-weighed measuring cylinder from a height of 100 cm from the upper edge of the cylinder until a cone is formed above the top of the cylinder. The cone without compaction of sand is removed flush with the edges of the vessel with a metal ruler, after which the vessel with sand is weighed.
9.1.5. Processing of results
Bulk density of sand ( r n) in kg / m 3 calculated by the formula
(18)
Where T - weight of the measuring vessel, kg;
T 1 - weight of a measuring vessel with sand, kg;
V - vessel volume, m 3.
The determination of the bulk density of the sand is carried out twice, each time taking a new portion of the sand.
Note. The bulk density of the sand and gravel mixture is determined in accordance with GOST 8269.
9.2. Definition of voidness
The voidness (volume of intergranular voids) of sand in a standard unconsolidated state is determined based on the values of the true density and bulk density of the sand, previously established in paragraphs. 8 and 9.1.
The voidness of the sand (Vm.p) as a percentage by volume is calculated by the formula
(19)
Where r - true density of sand, g / cm 3;
r n - bulk density of sand, kg / m 3.
10. DETERMINATION OF MOISTURE
10.1. The essence of the method
The moisture content is determined by comparing the mass of the sand in the state of natural moisture and after drying.
10.2. Equipment
Scales in accordance with GOST 29329 or GOST 24104.
Drying cabinet.
Baking tray.
10.3. Testing
A sample weighing 1000 g of sand is poured into a baking sheet and immediately weighed, and then dried in the same baking sheet to constant weight.
10.4. Processing of results
Sand moisture (W) as a percentage is calculated by the formula
(20)
Where T - the weight of the sample in a state of natural moisture;
T 1 - dry sample weight, g.
11. DETERMINATION OF REACTIVITY
The test is carried out in accordance with GOST 8269, using a sample of sand with a mass of at least 250 g.
12. DETERMINATION OF THE CONTENT OF SULPHATE AND SULFIDE COMPOUNDS
12.1. To determine the content of harmful sulfur-containing impurities in the sand, the total sulfur content is found, then the sulfate sulfur content and the sulfide sulfur content is calculated from their difference.
If the sand contains only sulfate compounds, the total sulfur content is not determined.
12.2. Determination of total sulfur content
12.2.1. Weight method
12.2.1.1. The essence of the method
The gravimetric method is based on the decomposition of a sample with a mixture of nitric and hydrochloric acids, followed by the precipitation of sulfur in the form of barium sulfate and the determination of the mass of the latter.
12.2.1.2.
A muffle furnace providing a heating temperature of 900 ° C.
Porcelain cups with a diameter of 15 cm in accordance with GOST 9147.
Glass glasses with a capacity of 100, 200, 300, 400 ml in accordance with GOST 23932.
Porcelain crucibles in accordance with GOST 9147.
Desiccator according to GOST 25336.
Bath water.
Calcium chloride (calcium chloride) in accordance with GOST 450, calcined at a temperature of 700-800 ° C.
Ash paper filters according to TU 6-09-1706-82.
Nitric acid according to GOST 4461.
Hydrochloric acid according to GOST 3118.
Ammonia water according to GOST 3760, 10% solution.
Barium chloride (barium chloride) according to GOST 4108, 10% solution.
Methyl orange according to TU 6-09-5169-84, 0.1% solution.
Silver nitrate (silver nitrate) according to GOST 1277, 1% solution.
Woven wire sieves with square meshes No. 005 and 0071 in accordance with GOST 6613.
12.2.1.3. Test preparation
An analytical sample of sand is sieved through a sieve with holes 5 mm in diameter and 100 g of sand is taken from the sieved part, which is crushed to a particle size passing through a sieve with a mesh No. 016, a sample weighing 50 g is taken from the resulting sand. The sample is crushed again to particle size passing through a sieve No. 0071.
The crushed sand is dried to constant weight, placed in a weighing bottle, stored in a desiccator over calcined calcium chloride, and weighed portions are taken from it for analysis ( T) weighing 0.5-2 g.
12.2.1.4. Analysis
A sample, weighed with an accuracy of 0.0002 g, is placed in a glass beaker with a capacity of 200 ml or a porcelain cup, moistened with a few drops of distilled water, add 30 ml of nitric acid, cover with glass and leave for 10-15 minutes. After the end of the reaction, add 10 ml of hydrochloric acid, stir with a glass rod, cover with glass and put a glass or a cup in a water bath. In 20-30 minutes after the cessation of the evolution of brown vapors of nitrogen oxides, the glass is removed and the contents of the glass or cup are evaporated to dryness. After cooling, the residue is moistened with 5-7 ml of hydrochloric acid and again evaporated to dryness. The operation is repeated 2-3 times, add 50 ml of hot water and boil until the salts are completely dissolved.
To precipitate the elements of the group of sesquioxides, 2-3 drops of methyl orange indicator are added to the solution and the ammonia solution is added until the color of the solution changes from red to yellow and the smell of ammonia appears. After 10 min, the coagulated sesquioxides precipitate is filtered through a “red ribbon” filter into a beaker with a capacity of 300-400 ml. The precipitate is washed with warm water with the addition of a few drops of ammonia solution. Hydrochloric acid is added to the filtrate until the color of the solution turns pink, and another 2.5 ml of acid is added.
The filtrate is diluted with water to a volume of 200-250 ml, heated to boiling, 10 ml of hot barium chloride solution is poured into it at one time, stirred, the solution is boiled for 5-10 minutes and left for at least 2 hours. The precipitate is filtered through a dense filter. blue tape ”and washed 10 times with small portions of cold water to remove chloride ions.
After cooling in a desiccator, the crucible with the sediment is weighed. Calcination is repeated until constant weight is obtained. To determine the sulfur content in the reagents used for the analysis, a "blind experiment" is carried out in parallel with the analysis. The amount of barium sulfate found by "blind experience" T 2, subtracted from the mass of barium sulfate T 1 obtained by analyzing the sample.
Note. The expression "blind experience" means that the test is carried out in the absence of the test object, using the same reagents and observing all the conditions of the experiment.
12.2.1.5. Processing of results
The total sulfate sulfur content ( NS 1) as a percentage based on SO 3 is calculated by the formula
(21)
Where T - sample weight, g;
T 1 - weight of barium sulfate sediment, g;
T 2 - mass of barium sulfate sediment in the “blind experiment”, g;
0.343 - conversion factor of barium sulfate to SO 3.
Allowable discrepancies between the results of two parallel analyzes at confidence level R= 0.95 should not exceed the values specified in table. 4. Otherwise, the analysis should be repeated until an acceptable discrepancy is obtained.
Table 4
|
Permissible discrepancy, abs. % |
|
|
Up to 0.5 |
0,10 |
|
St. 0.5 to 1.0 |
0,15 |
|
” 1,0 |
0,20 |
12.2.2. Iodometric titration method
12.2.2.1. The essence of the method
The method is based on the combustion of a sample in a flow of carbon dioxide at a temperature of 1300-1350 ° C, the absorption of the released SO 2 with a solution of iodine and titration with a solution of sodium thiosulfate of excess iodine, which did not enter into a reaction with the formed sulfurous acid.
12.2.2.2. Equipment, reagents and solutions
Installation for determining the sulfur content (Fig. 5).
Sodium thiosulfate according to GOST 27068, 0.005 N. solution.
Sodium carbonate (sodium carbonate) according to GOST 83.
Potassium dichromate (potassium dichromate) in accordance with GOST 4220, fixed.
Soluble starch according to GOST 10163, 1.0% solution.
Iodine in accordance with GOST 4159, 0.005 N solution.
Potassium iodide (potassium iodide) in accordance with GOST 4232.
Sulfuric acid according to GOST 4204, 0.1 n solution.
Analytical balance, measurement error 0.0002 g.
12.2.2.3. Preparation of 0.005 N sodium thiosulfate solution
To prepare a solution of sodium thiosulfate dissolve 1.25 g Na 2 S 2 O 3 5 H 2 O in 1 liter of freshly boiled distilled water and add 0.1 g of sodium carbonate. The solution is stirred and left for 10-12 days, after which its titer is determined by 0.01 N potassium dichromate solution prepared from the fixed channel.
To 10 ml of a 0.01 n solution of potassium dichromate add 50 ml of a 0.1 n solution of sulfuric acid, 2 g of dry potassium iodide and titrate with the prepared sodium thiosulfate solution until a straw-yellow color. Add a few drops of a 1% starch solution (the solution turns blue) and titrate until the solution becomes discolored. Correction factor to the titer of 0.005 N sodium thiosulfate solution determined by the formula
(22)
Where - the normality of the potassium dichromate solution;
10 - the volume of 0.01 n potassium dichromate solution, taken for titration, ml;
V - volume of 0.005 n sodium thiosulfate solution used for titration 10 ml of 0.01 n solution potassium dichromate, ml;
- normality of sodium thiosulfate solution.
The titer is checked at least once every 10 days.
Store the sodium thiosulfate solution in dark bottles.
12.2.2.4. Preparation of 0.005 N iodine solution
To prepare a solution of iodine, 0.63 g of crystalline iodine and 10 g of potassium iodide are dissolved in 15 ml of distilled water. The solution is transferred to a 1 L volumetric flask with a well-ground stopper, filled up to the mark with water, mixed and stored in the dark.
The titer of the prepared iodine solution is determined by the titrated solution of sodium thiosulfate prepared by the method described above (p. 12.2.2.3).
10 ml of 0.005 N iodine solution is titrated with 0.005 N sodium thiosulfate solution in the presence of starch.
The correction factor to the titer of 0.005 N iodine solution () is determined by the formula
(23)
Where - volume of 0.005 n sodium thiosulfate solution consumed for titration of iodine solution, ml;
- correction factor 0.005 N sodium thiosulfate solution;
- the normality of the iodine solution;
10 - the amount of iodine solution taken for titration, ml.
12.2.2.5. Test preparation
Test portions are prepared in accordance with clause 12.1.1.3, while the weight of the portions is taken equal to 0.1-1.0 g.
Before starting work, the furnace is heated to a temperature of 1300 ° C and the tightness of the installation is checked. To do this, close the tap in front of the absorption vessel and release carbon dioxide. The cessation of the passage of gas bubbles through the flushing bottle indicates the tightness of the installation.
Determine the coefficient TO, establishing the ratio between the concentrations of iodine solution and sodium thiosulfate. Carbon dioxide is passed through the installation for 3-5 minutes, the absorption vessel is filled 2/3 with water. From the burette, pour 10 ml of a titrated iodine solution, add 5 ml of a 1.0% starch solution and titrate with a sodium thiosulfate solution until the solution becomes discolored. The ratio of the concentration of solutions of iodine and sodium thiosulfate TO take equal to the average of the three definitions. Concentration ratio ratio TO under laboratory conditions, determined daily before testing.
12.2.2.6. Testing
The weighed portion, weighed to the nearest 0.0002 g, is placed in a pre-calcined boat. 250-300 ml of distilled water is poured into the absorption vessel, the volume of iodine solution measured by the burette, 5 ml of starch solution is added and stirred with a stream of carbon dioxide.
Installation diagram for the determination of sulfur content
1 - carbon dioxide cylinder; 2 - wash bottle with 5% solution
Copper sulphate; 3 - wash bottle with 5% potassium permanganate solution;
4 - calcined calcium chloride block; 5 - rubber plugs;
6 - electric tube furnace with silicite rods, providing
Heating temperature 1300 ° С; 7 - porcelain calcining tube
Length 70-75 mm, inner diameter 18-20 mm; 8 - porcelain
Boat No. 1 (length 70, width 9, height 7-5 mm) or porcelain
Boat No. 2 (length 95, width 12, height 10 mm) in accordance with GOST 9147;
9 - tap; 10 - absorption vessel; II - burette with iodine solution;
I2 - burette with sodium thiosulfate solution
Heck. 5
Note. All parts of the unit are butt-connected with rubber tubes. To prevent burning of rubber stoppers, the inner end surface is covered with asbestos gaskets.
A boat with a hitch is placed into a heated tube (from the carbon dioxide supply side) using a heat-resistant wire hook. Close the tube with a stopper and supply carbon dioxide (speed 90-100 bubbles per minute). The weighed portion is calcined for 10-15 minutes, making sure that the solution in the absorption vessel retains its blue color. Then the solution in the absorption vessel is titrated with sodium thiosulfate solution until discoloration. After the end of the titration, remove the boat from the oven, taking care not to contaminate the walls of the porcelain tube with the remnants of the sample.
A new portion of water, a solution of iodine and starch is poured into the absorption vessel, washed with water.
12.2.2.7. Processing of results
(24)
Where V - volume of iodine solution taken for titration, ml;
V1 - volume of sodium thiosulfate solution consumed for titration of excess iodine that has not reacted, ml;
TO - the ratio of the concentration of iodine solution and sodium thiosulfate;
A - volume of 0.005 n sodium thiosulfate solution consumed for titration of iodine solution, ml;
126.92 - 1 g-equiv of iodine, g;
10 - the volume of 0.005 n iodine solution taken for titration, ml;
1000 - volume of sodium thiosulfate solution, ml.
Allowable discrepancies between results of two parallel determinations at confidence level R= 0.95 should not exceed the values specified in table. 3. Otherwise, the experiment should be repeated until an acceptable discrepancy is obtained.
12.3. Determination of sulfate sulfur content
12.3.1. The essence of the method
The method is based on the decomposition of a sample with hydrochloric acid, followed by the precipitation of sulfur in the form of barium sulfate and the determination of the mass of the latter.
12.3.2. Equipment, reagents and solutions
For the analysis, use the equipment, reagents and solutions specified in clause 12.2.1.2, while using hydrochloric acid according to GOST 3118, solution 1: 3 (one volume part of concentrated hydrochloric acid and three volume parts of water).
12.3.3. Test preparation
The test portion is prepared according to clause 12.1.1.3, while the weight of the sample is taken equal to 1 g.
12.3.4. Testing
Hinge T placed in a glass with a capacity of 100-150 ml, covered with glass and add 40-50 ml of hydrochloric acid. After the release of gas bubbles has ceased, the glass is placed on the hotplate and kept at a low boil for 10-15 minutes. Sesquioxides are precipitated by adding 2-3 drops of methyl orange indicator and adding ammonia solution until the indicator color changes from red to yellow and the smell of ammonia appears. After 10 minutes, the precipitate is filtered off. The precipitate is washed with warm water with the addition of a few drops of ammonia solution.
The filtrate is neutralized with hydrochloric acid until the color of the solution turns pink and another 2.5 ml of acid is added. The solution is heated to a boil and 10 ml of hot barium chloride solution is added at one time, stirred, the solution is boiled for 5-10 minutes, and the solution is left for at least 2 hours. The precipitate is filtered through a thick blue ribbon filter and washed 10 times with small portions of cold water before removal of chloride ions.
The completeness of the removal of chloride ions is checked by the reaction with silver nitrate: a few drops of the filtrate are placed on glass and a drop of a 1% solution of silver nitrate is added. The absence of the formation of a white precipitate indicates the completeness of the removal of chloride ions.
A precipitate with a filter is placed in a porcelain crucible, previously calcined to constant weight at a temperature of 800-850 ° C, dried, incinerated, avoiding ignition of the filter, and calcined in an open crucible until the filter is completely burned out, and then at a temperature of 800-850 ° C in within 30-40 minutes.
After cooling in a desiccator, the crucible with the sediment is weighed. Calcination is repeated until constant weight is obtained.
In parallel with the analysis, a “blind experience” is carried out (see the note to clause 12.2.1.4). Barium sulfate amount T 2 found by "blind experience" is subtracted from the mass of barium sulfate T 1 obtained by analyzing the sample.
12.3.5. Processing of results
Acceptable discrepancies between the results of two parallel analyzes are taken in accordance with clause 12.2.1.5.
12.4. Determination of sulfide sulfur content
(27)
Where NS - total sulfur content in terms of SO 3,%;
X 1 - the content of sulfate sulfur in terms of SO 3,%.
13. DETERMINATION OF FROST RESISTANCE OF SAND FROM CRUSHING DEPOSITS
13.1. The essence of the method
The frost resistance of sand is determined by the loss of mass during successive freezing and thawing.
13.2. Equipment
Freezer chamber.
Drying cabinet.
Scales in accordance with GOST 29329 or GOST 24104.
Sieves with meshes No. 1.25; 016 in accordance with GOST 6613 and with round holes 5 mm in diameter.
A vessel for thawing samples.
Cloth bags made of dense fabric with double walls.
Trays.
13.3. Sample preparation
The laboratory sample is reduced to a mass of at least 1000 g, sieved on two sieves: the first with holes 5 mm in diameter and the second with a mesh No. 1.25 or 016, depending on the size of the test material, dried to constant weight, after which two weighed portions are taken weighing 400 g.
13.4. Testing
Each sample is placed in a bag that ensures the safety of the grains, immersed in a vessel with water for saturation for 48 hours. The bag with a sample is taken out of the water and placed in a freezer that ensures a gradual decrease in temperature to minus (20 ± 5) ° C.
Samples in the chamber at a steady-state temperature of minus (20 ± 5) ° С are kept for 4 hours, after which the bags with weighed portions are removed, immersed in a vessel with water having a temperature of 20 ° С, and kept for 2 hours.
After carrying out the required number of freezing and thawing cycles, the weighed portion from the bag is poured onto a control sieve with a mesh No. 1.25 or 016, carefully washing off the remaining grains from the walls of the bag. The weighed portion, which is on the control sieve, is washed, and the residue is dried to constant weight.
13.5. Processing of results
Weight loss of the sample ( NS mrz) as a percentage is calculated by the formula
(28)
Where T - sample weight before testing, g;
T 1 - weight of grains weighed on a control sieve with mesh No. 1.25 or 016 after testing, g.
APPLICATION
Reference
SCOPE OF TESTS
The name and scope of the tests are shown in table. 5.
Table 5
|
Application area |
||||
|
Test name |
Quality control at the manufacturer |
Geological |
Incoming control |
|
|
Acceptance |
Periodic |
Intelligence service |
At the consumer enterprise |
|
|
1. Determination of grain size composition and size modulus |
||||
|
2. Determination of the content of clay in lumps |
||||
|
3. Determination of the content of dust and clay particles |
||||
|
4. Determination of the presence of organic impurities |
||||
|
5. Determination of the mineralogical and petrographic composition |
||||
|
6. Determination of true density |
||||
|
7. Determination of bulk density and voidness |
||||
|
8. Determination of moisture |
||||
|
9. Determination of reactivity |
||||
|
10. Determination of the content of sulfate and sulfide compounds |
||||
|
11. Determination of frost resistance of sand from crushing screenings |
||||
Note. The “+” sign means that the test is being carried out; sign "- ”- do not carry out.
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of Industry of Building Materials of the USSR
CONTRACTORS
M. L. Nisnevich, Dr. Sciences (topic leader); N. S. Levkova, Cand. tech. sciences; E. I. Levina, Cand. tech. sciences; G. S. Zarzhitsky, Cand. tech. sciences; L. I. Levin; V.N. Tarasova, Cand. tech. sciences; A. I. Polyakova; E. A. Antonov; L. V. Bereznitsky, Cand. tech. sciences; I. I. Kurbatova tech. sciences; G. P. Abysova; MF Semizorov; T. A. Kochneva; A. V. Strelskiy; V. I. Novatorov; V. A. Bogoslovsky; T. A. Fironova
2. APPROVED AND PUT INTO EFFECT by the Decree of the State Construction Committee of the USSR dated 05.10.88 No. 203
3. Complies with ST SEV 5446-85, ST SEV 6317-88 (in terms of sampling and determination of grain composition)
4. Instead of GOST 8735-75 and GOST 25589-83
5. REFERENCE REGULATORY AND TECHNICAL DOCUMENTS
|
Designation of NTD referenced |
Item number, sub-item |
|
GOST 8.326-78 |
1.10 |
|
GOST 83-79 |
12.2.2.2 |
|
GOST 427-75 |
9.1.2 |
|
GOST 450-77 |
8.1.2; 8.2.2; 12.2.1.2 |
|
GOST 1277-75 |
12.2.1.2 |
|
GOST 1770-74 |
|
|
GOST 2184-77 |
8.1.2; 8.2.2 |
|
GOST 2874-82 |
|
|
GOST 3118-77 |
12.2.1.2; 12.3.2 |
|
GOST 3760-79 |
12.2.1.2 |
|
GOST 4108-72 |
12.2.1.2 |
|
GOST 4159-79 |
12.2.2.2 |
|
GOST 4204-77 |
12.2.2.2 |
|
GOST 4220-75 |
12.2.2.2 |
|
GOST 4232-74 |
12.2.2.2 |
|
GOST 4328-77 |
|
|
GOST 4461-77 |
12.2.1.2 |
|
GOST 5072-79 |
5.1.2, 5.2.2 |
|
GOST 6613-86 |
1.6, 3.2, 4.2, 5.2.2, 7.2, 12.2.1.2, 13.2 |
|
GOST 6709-72 |
8.1.2 |
|
GOST 8269-87 |
2.3, 5.3.1, 5.4.1, 9.1.5, 11, 12.2.1.3 |
|
GOST 8736-93 |
2.11 |
|
GOST 9147-80 |
5.2.2, 8.2.2, 12.2.1.2 |
|
GOST 10163-76 |
12.2.2.2 |
|
GOST 22524-77 |
8.1.2 |
|
GOST 23732-79 |
|
|
GOST 23932-90 |
12.2.1.2 |
|
GOST 24104-88 |
3.2, 4.2, 5.1.2, 5.2.2, 6.2, 7.2, 8.1.2, 8.2.2, 9.1.2, 10.2, 13.2 |
|
GOST 25336-82 |
8.1.2, 8.2.2, 12.2.1.2 |
|
GOST 25706-83 |
4.2, 7.2 |
|
GOST 27068-86 |