Many know that there is a sandy pillow under the foundation, however, not everyone can say exactly why it is needed and how it is created. As a result, newcomers in construction business often raw sand into the trench without any understanding and eventually only harm the whole design.
The pillow under the basement sole can perform three functions:
- Leveling. If the soil is not poured and not movable, then the only task of sand is to align the bottom of the trench or pit for uniform placement of the solution or the correct load distribution from the FBS.
Compensating. Bunched soils under the support of the house in winter can strongly affect the load distribution, leading in difficult cases to the destruction of the concrete tape or plate.
In this case, the object's task is to compensate for deformation, reduce them to an acceptable level for this foundation.
Replacing if an organometallic or organic soil (for example is a peat), then you have to put up with continued decomposition processes.
In this case, the soil will necessarily be movable, bunched and characterized by a low bearing capacity. It has to be removed on a greater depth, until the end of the organic layer and fall asleep with sand trench.
Which thickness need a pillow under the foundation, depends on which function it performs in this particular case.
Cushion device
The easiest way to create a subtype that performs an aligning role. As a rule, its thickness in this case does not exceed 15-20 cm. It is enough to fall asleep sand, carefully align, shed it with a small amount of water - moisturize and then ravage.
But this minimum you can do either on non-empty soils, or in the case of a deep linkage of the foundation, below the level of friction and support for non-deformable soil layers. In other cases, it is necessary to lay a compensation pillow. Its dimensions depend on the width of the soles of the foundation. The exact data can be calculated on the table.
| 50-70 | 2.4 * B. | 1,2 * B. |
| 70-100 | 2 * B. | 1,15 * B. |
| 100-120 | 1.8 * B. | 1.1 * B. |
For example, if the foundation is laid with a width of 60 cm, then the pillow width will be 60 * 2.4 \u003d 144 cm, and the height is 60 * 1.2 \u003d 72 cm. Ribbon foundation with a ribbon width Over 120 cm in a compensating pillow does not need .
A compensating sand pillow is laid as follows:
Sand is considered not a bunched material, also due to its structure, it prevents the capillary increase in moisture from the underlying layers to concrete. But this is all characteristic only for sand, not filled with water.
If a lot of moisture falls under the foundation, then it can radically change the properties of the pillow.
Therefore, in the area with a high level of groundwater or where there is a chance of getting under the concrete of sedimentary waters, it is mandatory to provide a moisture dreament system - drainage.
The process of bookmarking under the foundation of the replacement pillow fundamentally from compensating is not different. Only the role of geotextiles and water removal system increases. In any case, an important point is the correct traam. It is worth considering more.
See our video selection on the topic:
How to compact?
Pure sand practically does not give a shrinkage, but only after the proper seal. If you neglect this procedure and fulfill it unfair, high risk of drawdown with the subsequent destruction of the foundation.
So that everything turned out properly, the following rules should be followed:
It is more convenient and faster on sealing using vibrating lips or a special construction vibrator.
In some cases, you can use road construction techniques, and sometimes it turns out to be traaming manually.
What a way to choose is depends on the characteristics of the site and capabilities.
Selection of sand
Few people think about what sand is to choose for a pillow under the foundation. Take the one that will bring. However, the properties of this material affect the properties of the intake to a no less degree than the correctness of its bookmark.
For the foundation pillow, a washing career or river material is best suited.
The perfect choice is grave. Do not forget that other materials that meet the requirements presented are allowed.
However, it is difficult to correctly determine the loads and properties of one or another soil at home, so the easiest way to take the material that is guaranteed to fulfill its task.
See our video selection on the creation of a sandy pillow:
PROFFU »Records» Materials and Tools »Sandwife under the foundation
Before starting construction work, many pre-calculate the required amount of material. This is the right approach to such a serious cause. But at this stage, many questions arise. One of them: What sand is needed for the foundation?
The choice of such a material should be paid to special attention, since it is an important component, one of the main components used in the manufacture of concrete. From the quality of the mixture of the mixture and will depend on the durability of the foundation - the future foundation of the house. The modern market offers a huge range of sand, both natural and artificial. How to decide on the choice so that the foundation does not suffer from it, the article will tell.
Even inseparable in matters of construction, a person will be able to guess that for the foundation it is suitable exceptionally pure sand. Initially, various organic elements may be present in it: small twigs, grass and so on. For construction work, such material is not suitable, so there must be a seeded sand, cleaned of extraneous garbage.
However, simple shift cannot do if we are talking about such impurities as lime or clay. It is much more complicated to clean like sand, so when buying building materials, it is necessary to immediately pay attention. Permissible clay content in the sand is not more than five percent of the total mass, especially if a solution is made for the foundation. Otherwise, the building after a while will give shrinkage, cracks and will not be particularly reliable.
Check purity of sand
Before you choose which sand is needed for the foundation, you should check its purity. For this, a simple method is usually used. It will take any empty transparent bottle (glass or plastic). On one third, sand is falling asleep and filled with water half. Then the bottle is then intensely, so that the components are pretty mixed with each other. After that, they put it and wait five minutes for about ten minutes. If the water in the bottle became muddy and dirty, then such sand is not suitable for the foundation. If a foreign substance appeared on the surface, the layer of which exceeds the half-meter, then such a material cannot be taken too.
Now consider what kind of sand varieties exist.
Sand species for mounds
To ensure the reliability of the construction under construction, according to the standards, it is necessary to use bulk mixtures. The market realizes sedimentary rocks in three types, depending on the place of their extraction. This is the sand:
- career;
- river;
- nautical.
To answer the question of which one is most suitable for the foundation pillow, you should familiarize yourself with the characteristics and nuances of using each type.
Career sand
This raw material is mined in quarries, breaking rocks. An important indicator of reliability and strength of career sand is the parameter of its humidity. Admissible is the ratio from one to five percent. Suitable humidity can be determined visually. From the sand it will not be possible to blind a tight lump - he simply crushes.
The cheapest material is considered precisely the career sand. The price of it hesitates from three hundred to seven scores per cube. This is due to its low quality due to the large amount of clay impurities and other substances. Nevertheless, this raw material is considerable in demand.
Types of career sand
Depending on the type of processing, quartz raw materials is classified as follows.
1. Sand soil. This is a crude mixture with various impurities. As a rule, it align the country areas and fall asleep trenches.
2. Mooked sand. It is produced from waterfront deposits using hydromechanical equipment. The technology allows you to assemble the mixture without any impurities and unnecessary components. This material is used in the production of roads, paving slabs, concrete, bricks and reinforced concrete products.
3. Sedane sand. It is purified by a technical and mechanical method from large particles and stones. Typically, such raw materials are used to prepare the mass of plaster, laying solutions and in the casting of stone products.
River sand
This raw material is mined from the bottom of freshwater rivers. It rarely contains organic compounds and impurities. Therefore, river sand is considered a clean and natural product, which is designed for multipurpose use. This is the perfect material for laying the foundation, creating drainage and dilution of the solutions required for the interior decoration of the house. Due to the natural grinding of river sand, has a perfectly smooth shape and a small fraction within two millimeters.
Thanks to all listed advantages, this material becomes universal and desirable, but rather expensive raw materials for the foundation. Thus, the price of building sand, mined from the river, may vary from seven hundred to one thousand rubles per cube.
Classification of river sand
The raw material from the bottom of the river can be very different from each other. Therefore, it should be sorted out with a variety of grains. They can be several fractions: from 0.7 to 5 millimeters. The saturation of small sands is very sitting and tamped, so it is suitable only for lightweight buildings. Also distinguish the following types of bulk river material.
1. Large sand. These are pebbles of about five millimeters. They are obtained by splitting rocks with special crushing and grinding equipment.
2. Coarse sand. It has unobtrusive neutral color, is mined in dry rivers. Ideal for decoration and decoration of the room.
3. Mytoy river sand. These are medium-sized grains. They have gray or yellow, since they include iron and silicon oxides.
Positive sides of river sand
River sedimentary breeds have several positive qualities that are of great importance for the construction of the foundation. They meet technical and aesthetic requirements, do not rot and are not exposed to an aggressive environment. River sand is characterized by high moisture resistance and excellent noise insulation. It is also safe and environmentally friendly material.
For the construction of multi-storey buildings, only a large-phrase type is used, and the average baby will be suitable for sieves. Also, river sand is ideal for landscaping, playgrounds, landscape works and room decoration.
Sea sand
Sea crumb is also exactly the material as needed for the foundation. The sand is not very better than the river, but sometimes worse. This is explained by the presence of organic impurities (algae, seashells) and foreign objects. But the sea sand is necessarily purified from strangers and washed, so it is considered clean and high-quality. Due to this, this material is the most expensive, and not everyone is ready to pay for it. It is more appropriate to use sea crumb for construction where it is sold and cheaper.
Sand fractions
Any sand can be classified by its size. Experts allocate the following varieties of fractions.
- Very thin. It is a grain of a size of about 0.7 millimeters. They are suitable for the arrangement of playgrounds and are unsuitable for construction.
- Thin. Crupines in size reach from 0.7 to 1.0 millimeters. This is a loose material. You can not use such sand for construction, but it will be not bad for the preparation of skinny concrete.
- Small fraction. It is a grapple size of 1.5-2.0 millimeters. When it is used, the consumption of cement mixture increases.
- Average. Cruppers (2.0-2.5 millimeters) can be used to create standard concrete.
- Large. Sand particles in magnitude reach three millimeters. This fraction is ideal for breeding a high-quality concrete mix, which will be used in large-scale construction.
- Very large. Particles are more than three millimeters in diameter. They are added to the foundation pillow and are used to distribute the mass of the structure.
Sand selection for foundation
So what is the sand, river or career? Experts converge in the opinion that the first option is most suitable for the construction of foundations. It will create a layer, which will increase the strength, stability of the building, will prevent "walking" and the formation of cracks.
However, the river sand will not be for the pocket. In this case, it is allowed to use a career crumb, but must be soothing. A sandy-gravel mixture is also suitable, which improves the quality of the laying under the pillow.
Required amount of sand
Usually, one part of the cement is taken for five parts of the sand. But this calculation is suitable if the solution is made only from these two components. Sand, rubble and cement ratio for the foundation will be completely different. As a rule, they are taken in the following proportions: four parts of sand, two parts of rubble and one - cement.
As can be seen from the calculations, the sand should always be taken more than the other components. The number of materials itself directly depends on the height of the pillow and the building itself. Sand is better to buy with a small margin so that you do not have to buy it at an inappropriate moment. The remains can be accommodated for the preparation of solutions on the decoration of the walls or their masonry.
Summarizing
Answering the question of which sand is needed for the foundation, it should be noted that the ideal option is considered the river grains of the middle fraction. Such material has excellent properties for construction purposes. It allows you to build the most durable foundation that will flash for a long time and will be an excellent basis for the construction.
Purchase sand is necessary from reliable manufacturers, so as not to stumble upon poor-quality raw materials. It is recommended to check the material before purchasing the level of humidity and the number of extraneous impurities. It is also worth paying attention to the compliance of the procurement size. As a rule, in the cubic meter there should be approximately one and a half tons of sand.
When bookmarking the foundation, it is important correctly and competently choose building materials. Especially carefully you need to choose sand, as it is it depends on the strength of the solution for the foundationSo, the strength of the whole base. To the question of which sand is better to choose for the foundation, will reply in this article.
Sand selection
Sand for foundation is a bulk material obtained by from sedimentary rocks or artificial creation. The quality of sand does not depend on its method of receipt, it is important to take into account only its purity.
If you can find foreign objects in the size of a more half astimeter, it is not suitable for booking the foundation. The branches, leaves, organic trash can relate to foreign subjects.
Of course, you can try to clean the sand yourself, taking a sieve and sift it, but only imagine how much time and effort you will go to this process. Asking sand, you just remove large impurities, and what about the content of such elements that are undesirable in the sand for the construction of the foundation of the house, such as lime or clay.
Better immediately choose high-quality sand and start working. Remember that high-quality sand suitable for the manufacture of the solution should not contain more than 5% impurities. In addition, a large number of additives will worsen the strength of the sand, which will affect the foundation and house or building. Content gravel in the sand should not exceed 10%Since gravel is a constituent element of a solution for filling the foundation.
End, ideal sand you can detect only by conducting a special examination of his compliance with all standards in the laboratory, learn the percentage of impurities in the total mass and other indicators. But such an examination is a costly and long process, therefore i can determine the quality of the sand can be appropriate methods.
Fall off the sand, in a transparent bottle, by a third, and then pour up half with clean water and shake. After that, give a mixture stand for 5 minutes and look at the transparency of water. If it has become inspired and dirty, then the sand contains a lot of impurities. The emerging foreign substances, also a bad sign, and such sand is unsuitable for construction. If the water is transparent and without impurities, then the sand is ideal for booking the foundation.
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Sand origin
What sand is better - career or river, let's talk in this part.
Career sand
Career sand is mined in a quarry, destroying rocks. It is lower quality than river, but there are exceptions. When choosing a career sand an important factor in its reliability and strength is the humidity parameter. Its percentage should be from 1 to 5%. The humidity of 5% is determined on the eye in that it is impossible to make a tight ball or snowball from the sand - it crumbles.
To properly determine the humidity parameter, you can resort to the following method. To determine the humidity of the career sand, take the container, weigh it. Then, weigh 1 kg of sand in it and hold for about half an hour at a weak heating temperature, and then weigh the sand. Humidity will be calculated by the formula: the sand mass after heating is minus the mass of the container, divided by 100.
Career sand is cheaper at a price than river, since its production method is less expensive.
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River sand
The river sand is ideal for laying a foundation, and is also used in the dilution of solutions for the interior finish of the house or the creation of drainage. Therefore, such sand universal and multifunctional. Its small fraction from one and a half to two millimeters and the absence of impurities make it welcome, but expensive building material.
In addition to river sand allocate nauticalbut in modern construction it is applied there, from where it can be quickly brought, otherwise it the price exceeds even river. In quality, it is not better than the river, and sometimes even worse due to the impurities of the organicities (shells, algae) and foreign objects.
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Sand fractions
Depending on the size of the sand in the sand, the following types of fractions are distinguished:
- Very thin Contains grades size up to 0.7 mmBut due to the low fraction is unsuitable for the foundation. The foundation based on it will turn out as low as possible.
- Thin Contains sandbank sizes from 0.7 to 1 mm. Such sand is not thin, therefore it is also not suitable for the solution of the foundation. Usually thin sands are used to fill concrete.
- Very small Contains grades size to one and a halfBut still not suitable for filling the foundation, since the strength will still be optimal.
- Small Contains grades size from one and a half to 2 mm. And again it is not suitable for filling the foundation because of the large cost of cement for him.
- Middle Contains sandbank sizes from 2 to 2.5 mm And perfect for filling the foundation because of its strength and high performance properties.
- Large Contains sandbank sizes up to 3 mm and is intended for the manufacture of concrete high-quality and expensive marks. Such sand is very expensive.
- Sand increased size Contains sandbank sizes up to 3.5 mm and is used for the manufacture of sand pillows, designed to increase the strength of the base and distribute the load on all angles evenly.
Fill the foundation assumes that the verge of the middle sand you choose should be sharp. It is the sharp edges of the grace that increases the operational properties of the solution and make it as strong as possible.
Which sand is needed for concrete, plaster or brick laying. See what better, river or career.
This type of sand is purified by naturally, all impurities are washed out of it. Sometimes it is still found under the name "washed" particle size in river sand, as a rule, it happens from 0.3 to 0.5 mm.
Attention! !
Career sand
Career sand particles are much smaller than the river. Fraction from 0.6 to 3.2 mm. Quite often, in the sand from the career is clay or even the grass and roots of trees (usually when the career expansion)
What sand is better
It all depends on the goal.
For masonry. It is better to use career sand, it is not so fast "sits" in solution. The solution is obtained more plastic, due to the presence of clay.
For a screed.Almost always use the river, it is often very small pebbles, which provides additional bulk reinforcement.
For concrete.From concrete structures, high strength is always required. Clay increases plasticity, but at the same time strongly reduces strength, respectively, career sand is better not to use. To prepare concrete, it is better to buy river sand, naturally, you will need to add rubble.
For plaster.Career in this case will suit more, clay inclusions are not so critical, since the increased strength is not required, and the small fraction allows you to get a smoother surface.
Concrete consists of sand, cement, rubble and water. For each of these components, its role is assigned both in the manufacture of concrete structures and under its subsequent operation.
Sand for concrete is a small aggregator closing the emptiness generated between the crushed. It allows you to evenly distribute the internal stresses when the concrete is hardening and reduce the final value of the solution by reducing the amount of decisive cement.
The main thing is to take into account all the requirements for the preparation of the solution, choose those components that are best suited, and comply with the corresponding proportions.
Particle size
Bulk material is divided into two classes depending on the particle size: I and II class. As part of the more qualitative I class, there is no very small, fine and very thin group, which are undesirable components for the construction solutions. If they are presented, the connection between larger fractions is worse. Therefore, when preparing a solution, it is better to use sand I grade.
Classification by fractions
According to GOST 8736-93, the division can be:
- very large;
- increased size;
- large;
- middle;
- small;
- very small;
- subtle;
- very subtle.
In reality, division is usually conditionally. May be:
- small;
- middle;
- large.
To prepare a high-quality solid solution, it is better to use a large fraction. Preferably with a particle size of 2-2.5 mm. With a smaller size, the cost of the prevailing solution will increase significantly, and the quality will decrease.
Place of mining
The production site has a significant impact on the composition and properties of the material. It is customary to allocate river, career, sea and quartz. Mining sand in an open way.
Career
The career encounters clay and stones, so it can be used exclusively as a subtype to the foundations or concrete ties. When preparing a concrete, career sand can only be used after washing with water performed in the production site. When performing such an operation, clay and dust particles are removed.
River
River sand initially does not contain clay. It may be present at least stones. Actively used when performing construction work, allowing you to obtain a better solution. It is distinguished by the ability of natural fallout, therefore, when preparing a solution, it must be constantly mixed.
It should be borne in mind that the cost of the river is slightly higher than the career material. When choosing should be analyzed, which is better: reducing the cost of manufacturing a concrete structure or ensuring sufficient strength.
Sea and quartz
Sea in its characteristics is close to river. It is characterized by purity and homogeneity of the particle size distribution. Due to the possible detention of seashells, it may require additional cleaning.
Quartz is the result of mechanical crushing of rocks containing quartz. Uniform, clean and chemically inert. Get artificially.
Method of processing
Depending on the processing method, it may be:
- washing, obtained by washing;
- the seeded is obtained by sieving the initial raw materials to remove large particles and garbage.
Specifications
The requirements for sand used in the preparation of concrete are reflected in the relevant regulatory documents. Some characteristics can be tested exclusively in laboratory conditions, others can be monitored directly at the construction site.
Volume weight
An indicator reflecting a mass of 1 m³ in natural state. A wet cube with all sand impurities on average weighs about 1500 - 1800 kg. Preferred is less value.
Structure
The composition may be:
- granulometric, which reflects the ratio (in percent) of grains of different size;
- mineral: quartz, dolomite, field-sized and limestone;
- chemical, depending on those present in the elements, a possible area of \u200b\u200buse is determined.
An example of a granulometric composition:
An example of a chemical composition:
| SL02. | Al2O3. | Fe203. | TI02. | Saoft | MGO. | SO3 | K2O. | Na2O. | P.P.P. 1000 C. |
Sum | Content CO2. |
SACO3. |
| 78,26 | 6,48 | 1,45 | 0,12 | 5,89 | 0,70 | 0,12 | 0,96 | 0,64 | 5,35 | 99,97 | 4,92 | 11,2 |
An example of a mineral composition:
Humidity
As a rule, this characteristic is 5%. If the mixture is dried, the indicator will decrease to 1%. When moisturizing with precipitates, the value may increase to 10%. The amount of water added to a solution with such humidity should be reduced.
Humidity requirements are important, since it depends on the amount of water added to the solution. Humidity is determined by calcining a kilogram of the mixture. The indicator will be equal to the difference in the weight of wet and dried.
At the construction site, the level of humidity can be checked as follows. If the sand is squeezed into a lump, he will have to crumble. If this did not happen, the humidity of more than 5%. Although this indicator is still better controlled in laboratory conditions.
| Sand volume, cm3 (ml) | Humidity of sand,%, at the density of sand particles, g / cm3 | ||
| 2,6 | 2,65 | 2,7 | |
| 448 | 2 | 2,9 | 4,1 |
| 450 | 2,6 | 3,5 | 4,7 |
| 452 | 3,3 | 4,2 | 5,3 |
| 454 | 4 | 4,8 | 6 |
| 456 | 4,6 | 5,5 | 6,6 |
| 458 | 5,3 | 6,1 | 7,3 |
| 460 | 5,9 | 6,7 | 8 |
| 462 | 6,5 | 7,4 | 8,6 |
| 464 | 7,2 | 8 | 9,3 |
| 466 | 7,8 | 8,7 | 9,9 |
Porosity coefficient and bulk density
The porosity coefficient reflects the ability of sand and, accordingly, in the future of concrete to skip moisture. It can be determined exclusively in laboratory conditions.
The average value of the bulk density is considered to be 1.3 - 1.9 t / cubic meters. Optimal is 1.5 tons / cubic meters. Less importance may indicate the presence of unwanted impurities, more - about excessive moisture. The necessary information should be prescribed in the accompanying documents.
What to give preference?
To understand what sand is needed for concrete a specific brand, it is necessary to take into account the upcoming type of work.
Masonry
Brick and large-bordered masonry is better to produce using river. If it is necessary to increase the plasticity of the prepared solution to the river can be added a small amount of non-career, which will also help reduce costs.
Concrete
To prepare concrete, it is preferable to use medium or large river sand into which a little washed career can be added. It is worth noting that the patches of the career, unlike the river and sea, improper shape and rough surface. Under the influence of the aqueous medium, the surface of the particles is polished, which significantly worsens the adhesion with the other components of the solution.
However, flushing career is not always possible to completely remove clay. Therefore, when preparing a concrete mixture, it is preferable to use river sand. It is already washed. Particles of approximately the same size. It does not have clay, which significantly reduces the strength characteristics of the prepalanted solution.
Criterias of choice
Thus, choosing sand needs to be focused on:
- the cost - the river and the sea will cost more than the career.
Cooking concrete, withstanding proportions
To get high-quality concrete, it is necessary to properly withstand the ratio of sand and cement. The optimal ratio of components (C - cement (M400, M500); sh - rubble: P - sand) solution looks like this:
| Brand concrete | Mass ratio: C: Sh: P (kg) |
| 100 | 1:7:4,6 (1:8,1:5,8) |
| 150 | 1:5,7:3,5 (1:6,6:4,5) |
| 200 | 1:4,8:2,8 (1:5,6:3,5) |
| 250 | 1:3,9:2,1 (1:4,5:2,6) |
| 300 | 1:3,7:1,9 (1:4,3:2,4) |
| 400 | 1:2,7:1,2 (1:3,2:1,6) |
| 450 | 1:2,5:1,1 (1:2,9:1,4) |
Brand concrete is important. If it is below the M300, it is better to take sand with a particle size of less than 2.5 mm. Such a concrete is traditionally used to fill the foundation under the garage, one-story buildings, household buildings. For brands above the M350 used in the construction of multi-storey buildings, slabs of overlapping, armopoyarov, it is worth taking a river with a grain size of 3 mm.
In the most general case, when preparing a solution, you can use the following data:
| Brand concrete | Size of river sand particles, mm | Volume composition on 10 l: Sand: Crushed stone (L) | Mass ratio: Cement: Crushed stone: Sand (kg) |
| 100 | up to 2.5 | 41:61 (53:71) | 1:7:4,6 (1:8,1:5,8) |
| 150 | 32:50 (40:58) | 1:5,7:3,5 (1:6,6:4,5) | |
| 200 | 25:42 (32:49) | 1:4,8:2,8 (1:5,6:3,5) | |
| 250 | 19:34 (24:39) | 1:3,9:2,1 (1:4,5:2,6) | |
| 300 | 17:32 (22:37) | 1:3,7:1,9 (1:4,3:2,4) | |
| 400 | from 3.5. | 11:24 (14:28) | 1:2,7:1,2 (1:3,2:1,6) |
| 450 | 10:22 (12:25) | 1:2,5:1,1 (1:2,9:1,4) |
And water mixed in certain proportions, create such a superfrequency building material as concrete. Each ingredient plays its important role. So, the sands act as an integral component of a concrete mix, which fills the space between the crushed. The quality of small aggregate plays a key role, since the wear resistance and strength of the final product depends on the correct distribution of internal voltage.
General requirements when choosing
Sand for concrete, which is used for the manufacture of concrete solution, must comply with the norms of the GOST. The material is suitable if it contains less than ten percent of the particles with a fraction to 0.14 mm and no more than three percent of the impurities represented by dust, il and clay. It is the presence of the latter in the mixture that can negatively affect the frost-resistant and strength of concrete, since it covers the sand, without giving them a properly connecting to the rest of the components. Also, according to the norms, the content of large-sized particles is no longer allowed, and the share of 5-10 mm particles should lie within five percent of the total mass of the bulk component. Organic enclosures in the material represented by humus or vegetable elements should be absent.
Particle size
The river is the most optimal version of the filler of concrete mixes. To figure out which sand is needed for concrete, first determined with the most important parameter when choosing a bulk building material - the size module (fraction). Distinguish:
- very large (more than 3.5 mm size);
- increased fraction (in the range of 3-3.5 mm);
- large (2.5-3 mm);
- medium size (2-2.5 mm);
- small (1.5-2 mm);
- very small (1-1.5 mm);
- subtle (0.7-1 mm);
- very thin (up to 0.7 mm).
To determine the size module, manufacturers sift the sand alternately through sieve with fractions of 10 mm, 5 mm, 2.5 mm, 1.25 mm, 0.63 mm, 0.315 mm and 0.14 mm.
Simplified classification can be presented as follows:
- small;
- middle;
- large.
The manufacture of concrete involves the use of coarse sands with a sufficient amount of smaller grains, otherwise the concrete mixture will contain many voids. The emerging empties will fill cement, which means an increase in the cost of the final product. It is noted that the grains of the same fraction are badly in contact with each other, forming more free space. Therefore, massively use a mixture of different particle sizes to obtain the highest density between the elements.
Based on the size of the particles, bulk materials are classified into two classes. The first class is characterized by the absence of microparticles of less than 1.5 millimeters in diameter. Such sandy material is considered better, since the presence of a very small aggregate negatively affects the dedication of larger fractions. The second class, respectively, includes small components. That is why for the preparation of high-quality concrete use bulk first class.
Views
Sand is a small-grained mining sedimentary breed, found in the finished form or obtained by crushing rocks. In addition to the grain size, the placement is an important indicator, which determines its properties. Allocate:
- river;
- nautical;
- career;
- quartz.
The river sand is preferred because there is no clay and there is a very small amount of stone. It is somewhat more expensive than the other types of bulk, but the best quality. Its grains are homogeneous and have a smooth oval shape, the density of their settlement is much higher than the career, the form of which is not symmetric and has irregularities on the surface. It is extracted with the help of landfinding devices that suck water along with sand and carry the mixture into the storage. At the same time, water has an outflow back in the reservoir.
According to the properties of sea sand, it looks like a river. His feature is the content of small grains of seashells and sea stone. Therefore, it needs additional cleaning. Sea salt makes grains of homogeneous size and the right shape. It is the most expensive bulk material, because mining it takes place on the seabed using costly technologies.
The composition of the career bulk is often burdened by clay impurities and stones, so after prey, it needs washing from extraneous particles. He is the cheapest. The production of rock in sandy careers is the most massive.
Quartz sandy material is mined by artificial crushing of quartz rocks with special grinding installations. It is obtained without all sorts of impurities and is characterized by chemical neutrality. Based on processing options, there are the following methods of cleaning material:
- washing (method of purification by water washing);
- suitted (according to such a method, sieves are used for settlement).
Sandwashes occurs right at the site of mining. For this, the material is immersed in water and stirred several times. Thus, from the sands, various kinds of impurities and dust depart. Unnecessary particles float upstairs and are separated from the total mass. Such a procedure is carried out several times. True, the cost of bulk increases significantly. Sift - less costly procedure, but it does not save dust from microparticles.
Feature material
Sand can perfectly absorb and keep moisture. Miscellaneous Sand can have different both physical and chemical characteristics depending on the composition that may be:
- chemical;
- mineral;
- granulometric (mapping of particles in percentage depending on the fraction).
An important indicator acts actual weight of one meter of cubic sand. It varies within 1.5-1.8 tons. Little weight is considered better, as the mass of impurities is minimal.
Humidity plays far from a latter role. Normally, it should be 5%. The amount of water added to the concrete solution depends on this indicator. During home construction, you can check the moisture content of the material "on the eye": if the sand after compression in the fist does not crumble - it means that the normal level of humidity is exceeded, and the mixture will need a smaller amount of water.
In modern construction, sand is used very actively and almost everywhere. At the same time, there are about 10 different species of this material, but in the practice of Russian builders the most common two types are: career and river. Naturally, each type has the properties that determine its advantages and disadvantages of both building or finishing material. Therefore, non-professionals who have conceived by their own buildings some kind of design, often turn out to be in front of the choice:
Career Sand - Dignity and Disadvantages
Career is called sand extracted in careers from huge reservoirs located at a certain depth of ground. The quality of such sand is largely determined by its origin. The fact is that such underground sand is formed as a result of the weathelation of rocks. This process is in centuries, the decay products are deposited under the ground, with time turning into the blind masses of the sand.
The formation of sand deposits leads to weathering of such breeds, like mica, quartz, field spat and partially limestone. From what kind of rocks prevail in a particular area, the composition and characteristics of the sand depends.
What you need to take into account when solving the question of which sand is better career or river, this is possible the presence of impurities in the total mass of natural material. Pollution clay for career sands The phenomenon is normal and depending on the field only the concentration of foreign substance differs.
Another important characteristic is the heterogeneity of the fractions. In the mass of the career sand, both very small and very large particles are found, fragments often come across it, which in terms of sizes can be attributed to small gravel. However, in the case of the use of sand for construction purposes, it is impossible to name this property. The fact is that the heterogeneity of sand fractions and the presence of various impurities in it causes higher binding characteristics of the sand.
So, summarize. Career sand is distinguished by an increased roughness of the surface of the particles, as well as the angularity of their shape. Due to this, it is great for use as an element that provides an additional adhesion of binding additives as part of building mixtures. There are also areas of construction in which it is recommended to use precisely career sand. It turns out an excellent pillow under a swelled ribbon foundation. From this point of view with career sand, no other variety is compared.
River Sand - Cons and Pluses
Now consider the main characteristics and properties of river sand so that by comparison to try to answer the question of which sand is better career or river. River sand, as follows from his name, is extracted from River River. This circumstance is due extremely low content in it different impurities, especially, clay rocks and loams. They are simply washed out by the flow, which provides natural sand cleaning.
Also, the constant exposure to water to which river sand is exposed leads to particles are about the same size and almost perfect rounded form. Due to this, this material is actively used in landscape design to create the desired decorative effect.
One of the advantages of the material is the fact that for the arrangement of children's sandboxes or volleyball sites, it is necessary to use river sand.
If we talk about construction, then the main properties of river sand, except for shape and size, should be recognized as a low ability to absorb and retain moisture, as well as environmental purity and safety.
Given all this, river sand is used mainly to obtain decorative finishing materials. For example, if on the floor in the house it is planned to arrange a cement screed, then it is better for these purposes that exactly the river sand. It will not accumulate moisture, and also contributes to obtaining a smoother and smooth surface of the coating.
For the same reasons, river sand is a more preferred material for the manufacture of paving slabs. In Krasnoyarsk, it is also used in the device of drainage and filtering systems.
In essence, the only one, but the very significant minus of river sand as a building material - high price. The process of its production is associated with the use of complex expensive equipment, special barges and powerful hydraulic pumps are required to lift the breeds from the bottom of the bed and the subsequent washing. As a result, the cost of the final product turns out to be very high.
It is because of the significant cost when solving the question, which sand is better career or river, the builders often prefer the first. The question of the price becomes especially relevant when carrying out draft construction works, such as the establishment of the foundation, the creation of open areas for cars, etc. But for finishing works, especially internal, it is recommended not to save and choose river sandThe use of which provides a better result.
Our company is engaged in retail and wholesale supplies of river and career sand in Krasnoyarsk. For more information and order delivery, call the phone indicated on the page.
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