GOST 28013-98
Group W13
INTERSTATE STANDARD
CONSTRUCTION MORTARS
General specifications
General specifications
ISS 91.100.10
OKSTU 5870
Date of introduction 1999-07-01
Foreword
Foreword
1 DEVELOPED by the State Central Research and Design Institute for Complex Problems of Building Structures and Structures named after V.A. Kucherenko (TsNIISK named after V.A. Kucherenko), Research, Design and Engineering and Technological Institute of Concrete and Reinforced Concrete ( NIIZhB), with the participation of AOZT "Experimental Plant of Dry Mixes" and AO "Rosconitstroy" of the Russian Federation
INTRODUCED by Gosstroy of Russia
2 ADOPTED by the Interstate Scientific and Technical Commission for Standardization, Technical Regulation and Certification in Construction (ISTC) on November 12, 1998
Voted for adoption
State name | The name of the government building authority |
Republic of Armenia | Ministry of Urban Development of the Republic of Armenia |
The Republic of Kazakhstan | Committee on Housing and Construction Policy under the Ministry of Energy, Industry and Trade of the Republic of Kazakhstan |
Republic of Kyrgyzstan | State Inspection for Architecture and Construction under the Government of the Kyrgyz Republic |
The Republic of Moldova | Ministry of Territorial Development, Construction and Communal Services of the Republic of Moldova |
Russian Federation | Gosstroy of Russia |
The Republic of Tajikistan | Gosstroy of the Republic of Tajikistan |
The Republic of Uzbekistan | Goskomarkhitektstroy of the Republic of Uzbekistan |
3 REPLACE GOST 28013-89
4 PUT INTO EFFECT from July 1, 1999 as a state standard of the Russian Federation by the decree of the Gosstroy of Russia dated November 29, 1998 N 30
5 EDITION (July 2018), with Amendment No. 1 (IUS 11-2002)
Information on changes to this standard is published in the annual information index "National Standards", and the text of changes and amendments is published in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly information index "National Standards". Relevant information, notice and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet (www.gost.ru)
1 area of use
This standard applies to mortars for mineral binders used for masonry and installation of building structures in the construction of buildings and structures, fastening facing products, plaster.
The standard does not apply to special solutions (heat-resistant, chemically resistant, fire-resistant, heat and waterproofing, backfill, decorative, stressing, etc.).
The requirements set out in 4.3-4.13, 4.14.2-4.14.14, sections 5-7, annexes C and D of this standard are mandatory.
2 Normative references
The normative documents used in this standard are given in annex A.
3 Classification
3.1 Mortars are classified according to:
- the main purpose;
- the applied binder;
- medium density.
3.1.1 According to the main purpose, solutions are divided into:
- masonry (including for installation work);
- facing;
- plastering.
3.1.2 According to the used binders, solutions are divided into:
- simple (on one type of knitting);
- complex (mixed binders).
3.1.3 By average density, solutions are divided into:
- heavy;
- lungs.
3.2 The designation of the mortar when ordering must consist of an abbreviated designation indicating the degree of readiness (for dry mortar mixtures), purpose, type of binder used, grades for strength and mobility, average density (for light mortars) and the designation of this standard.
An example of the symbolic designation of a heavy mortar, ready to use, masonry, on a lime-gypsum binder, grade for strength M100, for mobility - P2:
Masonry mortar, lime-gypsum, M100, P2,
GOST 28013-98 .
For dry mortar mixture, light, plaster, cement binder, grade for strength M50 and for mobility - P3, average density D900:
Dry mortar plaster, cement mixture, M50, P3, D900, GOST 28013-98 .
4 General technical requirements
4.1 Mortars are prepared in accordance with the requirements of this standard according to the technological regulations approved by the manufacturer.
4.2 Properties of mortars include the properties of mortars and hardened mortars.
4.2.1 Basic properties of mortar mixtures:
- mobility;
- water retention capacity;
- delamination;
- application temperature;
- average density;
- humidity (for dry mortar mixtures).
4.2.2 Basic properties of the hardened mortar:
- compressive strength;
- frost resistance;
- average density.
If necessary, additional indicators can be established in accordance with GOST 4.233.
4.3 Depending on the mobility, mortar mixtures are subdivided in accordance with Table 1.
Table 1
Mobility grade P | Mobility rate by immersion of the cone, cm |
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4.4 The water-holding capacity of mortar mixtures should be at least 90%, clay-containing solutions - at least 93%.
4.5 The delamination of freshly prepared mixtures should not exceed 10%.
4.6 The mortar mixture should not contain fly ash more than 20% of the cement mass.
4.7 The temperature of mortar mixtures at the time of use should be:
a) masonry mortars for outdoor use - in accordance with the instructions in Table 2;
b) facing solutions for facing with glazed tiles at a minimum outside temperature, ° С, not less:
from 5 and up |
c) plaster mortars at a minimum outside temperature, ° С, not less:
from 5 and up | ||||
table 2
Average daily outside air temperature, ° С | Solution mixture temperature, ° С, not less |
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Masonry material |
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at wind speed, m / s |
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Up to minus 10 | ||||
From minus 10 to minus 20 | ||||
Below minus 20 | ||||
Note - For masonry mortar mixtures during installation work, the temperature of the mixture should be 10 ° C higher than indicated in the table |
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4.8 The moisture content of dry mortar mixtures should not exceed 0.1% by mass.
4.9 Normalized indicators of the quality of the hardened mortar must be ensured at the design age.
For the design age of the solution, unless otherwise specified in the design documentation, 28 days should be taken for solutions on all types of binders, except for gypsum and gypsum-containing ones.
The design age of solutions for gypsum and gypsum-containing binders is 7 days.
(Modified edition, Amendment N 1).
4.10 The compressive strength of solutions at the design age is characterized by grades: M4, M10, M25, M50, M75, M100, M150, M200.
Compressive strength grade is prescribed and controlled for all types of solutions.
4.11 Frost resistance of solutions is characterized by grades.
The following frost resistance grades are established for solutions: F10, F15, F25, F35, F50, F75, F100, F150, F200.
For solutions of grades for compressive strength M4 and M10, as well as for solutions prepared without the use of hydraulic binders, frost resistance grades are not prescribed or controlled.
4.12 The average density,, of the hardened solutions at the design age should be, kg / m:
Heavy solutions | 1500 and more | |||
Light solutions | less than 1500. | |||
The standardized value of the average density of solutions is set by the consumer in accordance with the project of work.
4.13 The deviation of the average density of the solution in the direction of increase is allowed no more than 10% established by the project.
4.14 Requirements for materials for the preparation of mortars
4.14.1 The materials used for the preparation of mortars must comply with the requirements of standards or specifications for these materials, as well as the requirements of this standard.
4.14.2 The following should be used as binders:
- gypsum binders in accordance with GOST 125;
- building lime in accordance with GOST 9179;
- Portland cement and slag Portland cement according to GOST 10178;
- pozzolanic and sulfate-resistant cements in accordance with GOST 22266;
- cements for mortars in accordance with GOST 25328;
- clay according to Appendix B;
- others, including mixed binders, according to regulatory documents for a specific type of binders.
4.14.3 Binding materials for the preparation of solutions should be selected depending on their purpose, type of structures and their operating conditions.
4.14.4 Consumption of cement per 1 m3 of sand in mortars based on cement and cement-containing binders should be at least 100 kg, and for masonry mortars, depending on the type of structures and their operating conditions, not less than that given in Appendix D.
4.14.6 Lime binder is used in the form of hydrated lime (fluff), lime dough, milk of lime.
Milk of lime must have a density of at least 1200 kg / m3 and contain at least 30% lime by weight.
Lime binder for plastering and facing mortars should not contain undamped lime particles.
The dough of lime must be at least 5 ° C.
4.14.7 The following should be used as a placeholder:
- sand for construction work in accordance with GOST 8736;
- fly ash in accordance with GOST 25818;
- ash and slag sand in accordance with GOST 25592;
- porous sands in accordance with GOST 25820;
- sand from slags of thermal power plants in accordance with GOST 26644;
- sand from slags of ferrous and nonferrous metallurgy for concrete in accordance with GOST 5578.
4.14.8 The largest size of the aggregate grains should be, mm, not more than:
Masonry (except rubble masonry) | ||||
Rubble masonry | ||||
Plastering (except for the covering layer) | ||||
Plastering overcoat | ||||
Facing | ||||
4.14.9 When heating aggregates, their temperature, depending on the applied binder, should not be higher, ° С, when applied:
Cement binder | ||||
Cement-lime, cement-clay and clay binder | ||||
Lime, clay-lime, gypsum and lime-gypsum binder | ||||
4.14.11 Specific effective activity of natural radionuclides of materials used for the preparation of mortar mixtures should not exceed the limit values depending on the field of application of mortar mixtures in accordance with GOST 30108.
4.14.12 Chemical additives must comply with the requirements of GOST 24211.
Additives are introduced into ready-to-use mortar mixtures in the form of aqueous solutions or aqueous suspensions, in dry mortar mixtures - in the form of a water-soluble powder or granules.
4.14.13 Water for mixing mortar mixtures and preparing additives is used in accordance with GOST 23732.
4.14.14 Bulk starting materials for mortar mixtures are dosed by weight, liquid components are dosed by weight or volume.
The dosing error should not exceed ± 1% for binders, water and additives, and ± 2% for aggregates.
For mortar mixing plants with a capacity of up to 5 m / h, volumetric dosing of all materials with the same errors is allowed.
4.15 Marking, packaging
4.15.1 Dry mortar mixtures are packed in bags made of polyethylene film in accordance with GOST 10354 weighing up to 8 kg or paper bags in accordance with GOST 2226 weighing up to 50 kg.
4.15.2 Packaged dry mortar mixtures should be marked on each package. The marking must be clearly affixed to the package with indelible paint.
4.15.3 Mortar mixtures must have a quality document.
The manufacturer must accompany the dry mortar mixture with a label or marking applied to the packaging, and the ready-to-use mortar mixture dispensed into the vehicle with a quality document, which must contain the following data:
- name or trademark and address of the manufacturer;
- conventional designation of the mortar according to 3.2;
- the class of materials used for the preparation of the mixture, according to the specific effective activity of natural radionuclides and the digital value;
- grade for compressive strength;
- brand for mobility (P);
- the volume of water required for the preparation of the mortar mixture, l / kg (for dry mortar mixtures);
- the type and amount of the added additive (% of the mass of the binder);
- shelf life (for dry mortar mixtures), months;
- weight (for dry mortar mixtures), kg;
- the amount of the mixture (for ready-to-use mortar mixtures), m;
- date of preparation;
- application temperature, ° С;
- designation of this standard.
If necessary, the marking and the quality document may contain additional data.
The quality document must be signed by the manufacturer's official responsible for technical control.
5 Acceptance rules
5.1 Mortar mixtures must be accepted by the manufacturer's technical control.
5.2 Mortar mixtures and solutions are accepted in batches by carrying out acceptance and periodic control.
For a batch of a mortar mixture and a solution, the amount of a mixture of one nominal composition is taken with the quality of its constituent materials unchanged, prepared using a single technology.
The volume of the batch is set by agreement with the consumer - not less than the output of one shift, but not more than the daily output of the mortar mixer.
5.3 All mortar mixtures and solutions are subject to acceptance control for all standardized quality indicators.
5.4 At the acceptance of each batch, at least five point samples are taken from the mortar mixture.
5.4.1 Spot samples are taken at the place of preparation of the mortar mixture and / or at the place of its application from several batches or places of the container into which the mixture is loaded. The sampling points from the container should be located at different depths. With continuous supply of the solution mixture, point samples are taken at unequal time intervals for 5-10 minutes.
5.4.2 After sampling, point samples are combined into a general sample, the mass of which should be sufficient to determine all controlled quality indicators of mortar mixtures and solutions. The sample taken is thoroughly mixed before testing (except for mixtures containing air-entraining additives).
Mortar mixtures containing air-entraining, foaming and gas-forming additives are not additionally mixed before testing.
5.4.3 Testing of a ready-to-use mortar mixture should be started during the period of maintaining the specified mobility.
5.5 The mobility and average density of the mortar mixture in each batch is controlled at least once per shift at the manufacturer's office after the mixture is unloaded from the mixer.
The moisture content of dry mortar mixtures is controlled in each batch.
The strength of the solution is determined in each batch of the mixture.
The standardized technological indicators of the quality of mortar mixtures provided for in the supply contract (average density, temperature, delamination, water retention capacity), and the frost resistance of the solution are monitored in time as agreed with the consumer, but at least once every 6 months, as well as when the quality of the initial materials, composition of the solution and technology of its preparation.
5.6 Radiation-hygienic assessment of materials used for the preparation of mortar mixtures is carried out according to quality documents issued by the enterprises - suppliers of these materials.
In the absence of data on the content of natural radionuclides, the manufacturer determines the specific effective activity of natural radionuclides of materials in accordance with GOST 30108 once a year, as well as at each change of supplier.
5.7 Ready-to-use mortar mixtures are dispensed and taken by volume. The volume of the mortar mixture is determined by the output of the mortar mixer or by the volume of the transport or measuring container.
Dry mortar mixtures are released and taken by weight.
5.8 If, when checking the quality of the mortar, a discrepancy is revealed in at least one of the technical requirements of the standard, this batch of mortar is rejected.
5.9 The consumer has the right to carry out a control check of the quantity and quality of the mortar mixture in accordance with the requirements of this standard according to the methods of GOST 5802.
5.10 The manufacturer is obliged to inform the consumer at his request of the results of control tests no later than 3 days after their completion, and in case of non-confirmation of the standardized indicator, inform the consumer about it immediately.
6 Control methods
6.1 Samples of mortar mixtures are taken in accordance with the requirements of 5.4, 5.4.1 and 5.4.2.
6.2 Materials for preparing mortar mixtures are tested in accordance with the requirements of standards and specifications for these materials.
6.3 The quality of chemical additives is determined by the indicator of their effectiveness on the properties of mortars in accordance with GOST 30459.
6.4 The concentration of the working solution of additives is determined by a hydrometer in accordance with GOST 18481 in accordance with the requirements of standards and specifications for specific types of additives.
6.5 Specific effective activity of natural radionuclides in materials for the preparation of mortar mixtures is determined in accordance with GOST 30108.
6.6 The mobility, average density, water retention capacity and stratification of mortar mixtures are determined in accordance with GOST 5802.
6.7 The volume of entrained air of mortar mixtures is determined in accordance with GOST 10181.
6.8 The temperature of freshly prepared mortar mixtures is measured with a thermometer, immersing it in the mixture to a depth of at least 5 cm.
6.9 Compressive strength, frost resistance and average density of the hardened solutions are determined in accordance with GOST 5802.
6.10 The moisture content of dry mortar mixtures is determined in accordance with GOST 8735.
7 Transport and storage
7.1 Transport
7.1.1 Ready-to-use mortar mixtures should be delivered to the consumer in vehicles specially designed for their transportation.
With the consent of the consumer, it is allowed to transport mixtures in bunkers (buckets).
7.1.2 The methods of transportation of mortar mixtures used must exclude the loss of the binder dough, the ingress of atmospheric precipitation and impurities into the mixture.
7.1.3 Packaged dry mortar mixtures are transported by road, rail and other types of transport in accordance with the rules for the carriage and fastening of goods in force for this type of transport.
7.2 Storage
7.2.1 Ready-to-use mortar mixtures delivered to the construction site must be loaded into mixer-loaders or other containers, provided that the specified properties of the mixtures are preserved.
7.2.2 Packaged mortar dry mixes are stored in covered dry rooms.
Bags with dry mix should be stored at a temperature not lower than 5 ° C under conditions that ensure the integrity of the packaging and protection from moisture.
7.2.3 The shelf life of the dry mortar mixture is 6 months from the date of preparation.
At the end of the shelf life, the mixture should be checked for compliance with the requirements of this standard. In case of compliance, the mixture can be used as directed.
APPENDIX A (reference). List of normative documents
APPENDIX A
(reference)
GOST 4.233-86 SPKP. Construction. Building solutions. Nomenclature of indicators
GOST 125-79 Plaster binders. Technical conditions
GOST 2226-2013 Bags made of paper and combined materials. General specifications
GOST 2642.5-2016 Refractories and refractory raw materials. Methods for the determination of iron (III) oxide
GOST 2642.11-97 Refractories and refractory raw materials. Methods for the determination of potassium and sodium oxides
GOST 3594.4-77 Forming clays. Methods for determination of sulfur content
GOST 5578-94 Crushed stone and sand from slags of ferrous and non-ferrous metallurgy for concrete. Technical conditions
GOST 5802-86 Building solutions. Test methods
GOST 8735-88 Sand for construction work. Test methods
GOST 8736-2014 Sand for construction work. Technical conditions
GOST 9179-77 Building lime. Technical conditions
GOST 10178-85 Portland cement and slag Portland cement. Technical conditions
GOST 10181-2014 Concrete mixtures. Test methods
GOST 10354-82 Polyethylene film. Technical conditions
GOST 18481-81 Glass hydrometers and cylinders. Technical conditions
GOST 21216-2014
GOST 21216-2014 Clay raw material. Test methods
GOST 22266-2013 Sulfate-resistant cements. Technical conditions
GOST 23732-2011 Water for concrete and mortars. Technical conditions
GOST 24211-2008 Additives for concrete and mortars. General specifications
GOST 25328-82 Cement for mortars. Technical conditions
GOST 25592-91 Ash and slag mixtures of thermal power plants for concrete. Technical conditions
GOST 25818-2017 Fly ash from thermal power plants for concrete. Technical conditions
GOST 25820-2000 Light concretes. Technical conditions
GOST 26633-2015 Heavy and fine-grained concretes. Technical conditions
GOST 26644-85 Crushed stone and sand from slag of thermal power plants for concrete. Technical conditions
GOST 30108-94 Building materials and products. Determination of the specific effective activity of natural radionuclides
GOST 30459-2008 Additives for concrete. Methods for determining effectiveness
SNiP II-3-79 * Construction heat engineering
APPENDIX B (recommended). The mobility of the mortar mixture at the site of application, depending on the purpose of the solution
Table B.1
The main purpose of the solution | Immersion depth of the cone, cm | Mobility grade P |
A Masonry: | ||
For rubble masonry: | ||
vibrated | ||
non-vibrated | ||
For hollow brick or ceramic stone masonry | ||
For solid brick masonry; ceramic stones; concrete stones or stones from light rocks | ||
For filling voids in masonry and feeding with a mortar pump | ||
For making a bed when installing walls from large concrete blocks and panels; jointing horizontal and vertical joints in walls made of panels and large concrete blocks | ||
B Facing: | ||
For fixing natural stone slabs and ceramic tiles to finished brick walls | ||
For fastening facing products of lightweight concrete panels and blocks in the factory | ||
In Plastering: | ||
soil solution | ||
spray solution: | ||
with manual application | ||
with a mechanized application | ||
coating solution: | ||
without the use of plaster | ||
using plaster |
APPENDIX B (mandatory). Clay for mortars. Technical requirements
APPENDIX B
(required)
These technical requirements apply to clay intended for the preparation of mortars.
B.1 Clay specifications
B.1.3 The content of chemical constituents from the mass of dry clay should not exceed,%:
- sulfates and sulfides in terms of - 1;
- sulfide sulfur in terms of - 0.3;
- mica - 3;
- soluble salts (causing efflorescence and efflorescence):
the amount of iron oxides - 14;
the sum of potassium and sodium oxides is 7.
B.1.4 Clay should not contain organic impurities in quantities that impart a dark color.
B.2 Test methods for clay
B.2.1 The particle size distribution of clay is determined according to GOST 21216.2 and GOST 21216.12. B.2.4 The mica content is determined by the petrographic method according to
Operating conditions of enclosing structures, humidity conditions of premises according to SNiP II-3-79 *
Minimum consumption of cement in masonry mortar per 1 m of dry sand, kg
In dry and normal room conditions
When the room is humid
In wet room mode
UDC 666.971.001.4:006.354 | ISS 91.100.10 | ||
Key words: mortars, mineral binders, masonry, installation of building structures; mortars for masonry, facing, plastering |
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Electronic text of the document
prepared by JSC "Kodeks" and verified by:
official publication
M .: Standartinform, 2018
Binders are known for their widespread use in the construction industry for the preparation of concretes and mortars used in the construction of buildings, structures and other structures. There are many varieties of them, and today we will briefly touch on the main existing subgroups.
Classification of binders
By their origin, they can belong to the organic or inorganic group. The first includes all kinds of bitumens, resins, tar and pitches. The main area of their application is the manufacture of roofing coverings, which can be roll or piece type, asphalt concrete and many different waterproofing materials. Their main distinguishing quality is hydrophobicity, that is, the ability to soften and take on a working state during heating or when interacting with any organic liquid.
The second group - inorganic binders - consists of lime, gypsum and cement. All of them are in demand in the process of preparing concrete and a wide variety of mortars. The appearance of inorganic binders is represented by a finely ground material, which, during mixing with water, turns into a liquid-plastic pasty mass, hardening to the state of a solid stone.
What is typical for them
The main properties of inorganic binders are hydrophilicity, plasticity when interacting with water and the ability to pass to a solid state from a semi-liquid pasty. This is precisely how they differ from the representatives of the first group.
According to the method of hardening, inorganic binders are considered air, hydraulic, acidic and autoclave hardening. This division depends on the ability to long-term resistance to natural climatic factors.
Air binders harden by interacting with water and, forming a strong stone, can remain in this state in the air for a long period of time. But if the products and building structures made with their use are subjected to regular moistening, then this strength will be quickly lost. Buildings and structures of this type are easily subject to destruction.
What is included in this group? This traditionally includes gypsum magnesian binders - clay, air lime. If we consider their chemical composition, then this entire group, in turn, can be subdivided into four more. This means that all air binders are either calcareous (based on calcium oxide), or magnesia (which include caustic magnesite), or gypsum binders based on calcium sulfate, or are liquid glass - potassium or sodium silicate, existing in the form of an aqueous solution.
Moving on to “watery” materials
Now let's look at another group - hydraulic binders. They tend to harden, and also maintain strength characteristics for a long time in not only air, but also water. Their chemical composition is quite complex and is a combination of various oxides.
This entire large group, in turn, can be divided into cements of silicate origin, which contain about 75% of calcium silicates (mainly, we are talking about Portland cement with its varieties, this group forms the basis of the range of modern building materials) and another subgroup - aluminate cements based on calcium aluminate (the most famous representatives are all types of alumina cement). The third group includes roman cement and hydraulic lime.
What binders are acid resistant? It is an acid-resistant quartz cement that exists in the form of a finely ground mixture of quartz sand with silicon. Such a mixture is closed with an aqueous solution of sodium silicate or potassium.
A characteristic feature of the group of acid-resistant binders is their ability, having passed the initial stage of hardening in air, for a long time to resist the aggressive influence of various acids.
Organic in construction
Another large subgroup - organic binders (consisting, as already mentioned, mainly of varieties of asphalt and bituminous materials) has a completely different nature. The same asphalt can be artificial or natural. It mixes bitumen with minerals in the form of limestone or sandstone.
In the construction industry, asphalt is widely used in road construction and airfield construction as a mixture of sand, gravel or crushed stone with bitumen. The same composition is used for asphalt, which is used in the form of waterproofing.
What is bitumen? This is an organic substance (either natural or artificial), which contains high molecular weight hydrocarbons or their derivatives containing nitrogen, oxygen and sulfur. The scope of application of bitumen is very wide and varies from road and housing construction to chemical and paint industry.
Under tar is understood as binders of organic origin, which include aromatic high-molecular carbohydrates and their derivatives - sulfuric, acidic and nitrogenous.
Their beneficial qualities
The main requirements that exist for the organic group of binders are to have a sufficient degree of viscosity at the moment of interaction with a solid surface, which would make it possible to manifest high wetting and enveloping properties with the formation of a waterproof film. Another requirement is the ability to maintain these qualities over a long period of time.
These binders have found their use in the construction of roads and city streets, they cover airfields and highways, arrange sidewalks and floors in basements and industrial buildings.
Let us now consider the main types of building materials belonging to the two listed groups. Let us recall again - the inorganic group is mainly subdivided into those that harden in air and those that are capable of doing this in an aquatic environment.
Astringents - Building Materials
The well-known clay is one of the most common binders that harden in the air. She found her application in the construction of a wide variety of buildings. It is a clay sedimentary rock that exists as a mixture of microscopic dust particles with sand and small clay inclusions. The smallest of them are called finely dispersed. It is their presence that allows it to turn into a pasty substance when it gets into a humid environment. After drying, this plastic mass easily hardens in its predetermined form.
If such a form is burned, then the resulting stone of artificial origin has a sufficiently high strength. Like other mineral binders, due to the different composition of the clay, it can be of a variety of shades. From solutions based on them, fireplaces, stoves are laid, and bricks are also molded. They can also be skinny, oily and medium. Clay-chamotte possesses refractory qualities, therefore it is indispensable for the construction of fireplaces and stoves.
What is lime
Another very well-known and widely used binder is called airborne building lime and is obtained from rocks, namely chalk, dolomite, limestone, shell rock. The main oxide in it can be different, depending on this, air lime is usually divided into dolomite, magnesian, calcium. All three varieties are obtained by burning limestones of the corresponding origin in a kiln.
Air lime can be either quicklime or slaked (or hydrated). The latter is formed in the process of extinguishing one of the three above.
If you look at the existing lime fractions, you can classify it as lumpy or powdery. Quicklime is a fairly large porous lumps. In the process of extinguishing with water, a lime dough is formed from it. To “extract” powdered lime from lumpy lime, you should perform the process of hydration (slaking), or grind the lumps. It can be used with or without additives. The additives are slags, active minerals and sand of quartz origin.
All about plaster
The next material is alabaster, or gypsum. It is obtained by thermally treating crushed gypsum stone. Gypsum hardens by going through three intermediate stages, consisting of its dissolution, followed by colloidation and then crystallization. When passing through the first stage, a saturated solution of gypsum dihydrate is formed. As it hardens, it increases in volume and acquires an even white surface.
Using coloring pigments, it is possible to give plaster products any color shades. The setting process of this binder normally begins after 4 minutes from the start of mixing. The end of solidification occurs between 6 and 30 minutes later.
In the process of setting, the mixture of gypsum and water must not be stirred and tamped in order to avoid the risk of loss of astringent qualities. There are a lot of gypsum grades, they are designated by various numbers characterizing the degree of compressive strength.
It is sold packaged in bags of different sizes. Gypsum has found the widest application in the design of the interiors of residential buildings and public buildings. For a long time, it has been customary to cast a variety of curly shapes from it. It should be stored exclusively in a dry room, and the shelf life is limited due to the possible loss of strength as the main useful quality.
And more about plaster
Stucco looks like a powder in color ranging from grayish to bright white. If you mix it with water, a characteristic reaction begins, and the mixture heats up. It is customary to add special materials to gypsum, called retention additives, the purpose of which is to improve the consistency and adhesion to the surface during plastering, as well as slightly extend the hardening period.
In order to increase the volume of the material without losing its working properties, fillers (for example, from expanded perlite or mica) are introduced. Special high-strength gypsum is fired at high temperatures; in the process, crystalline water is removed from it. Its hardening period is increased to 20 hours, and its hardness is much higher than that of other varieties.
The plaster is impregnated and marbled (bright white, slowly hardening and used for plastering internal surfaces) is obtained, and various fillers and retention additives are introduced into it during manufacture. The main point of most of these additives is to serve as a set retarder. In order to produce internal plaster, it is prepared in plastering machines with the possible addition of certain fillers, for example, sand.
From it, dry plaster or gypsum plasterboard building boards are obtained, gypsum is also used when filling the joints between them. There is a filler gypsum with similar properties.
Let's talk about cements
What other properties do hydraulic binders have? The process of their hardening, which began in air, continues in water, and their strength is preserved and even increases. The characteristic and best known members of the hydraulic binders family are, of course, cements. They are marked according to their strength, and the grade of a particular sample is determined by setting the ultimate bending and compressive load. Moreover, each of the samples must be made in the accepted proportion of cement and sand and pass the test for a certain period of 28 days.
The setting speed of cement can also be different - slow, normal or fast. Likewise, depending on the rate of hardening, any cement can be conventional, fast-hardening or extra fast-hardening.
As an example in this group, we can name Portland cement, which exists in the form of a fine gray powder with a slight greenish tint with the possible introduction of additives, which can be from granular slag (Portland slag cement).
About the speed of hardening
Quality testing (as well as production) of binders is carried out in compliance with numerous standards. For each of the existing groups, restrictions have been developed that determine the standard time for the beginning and end of setting, counting from the moment of water mixing.
Another cement - alumina - belongs to the fast-hardening hydraulic binders. It looks like a fine powder of brown, gray, greenish or black color (depending on the processing method and the original ingredients). In terms of fineness of grinding, it slightly exceeds Portland cement and requires a slightly larger volume of water.
Mixed types of binders are those that can harden both in air and water and are used in the production of only unreinforced concrete or mortars.
Bitumen and their scope
As for the most popular organic binders, the family includes a variety of bitumen and tar, ranging in color from black to dark brown. The traditional area in which such binders are used is in waterproofing work. This building material is water-resistant, waterproof, weather-resistant and highly resilient. This group of binders can be softened and liquefied by heating. With a decrease in temperature, their viscosity increases and can be completely lost.
This group, first of all, consists of bitumen of natural origin, as well as bitumen obtained from petroleum refining. Their chemical composition is compounds of molecules of oxygen, hydrogen, sulfur and nitrogen. Petroleum bitumen (liquid, solid and semi-solid) is in demand in construction.
By their purpose, they can also be classified into one of three groups - roofing, construction or road. An impregnating composition is prepared from roofing, roofing material and many different mastics are produced.
Industrial bitumen of hard and resilient-hard grades is produced by the high-vacuum method with additional processing stages, at which the oil boils at high temperatures. Oxidized ones are considered especially resistant to the drop of heat and cold. There are also mixtures of bitumen with polymers that affect the degree of their viscosity. A characteristic feature of all types is the ability to change the consistency depending on the temperature, and different phases can alternate repeatedly. The adhesive properties of the family of bituminous binders are based on it.
Why are they valuable
The degree of expansion of bitumen under the influence of high temperatures in comparison with mineral materials is 20-30 times greater. Their valuable qualities are water resistance, resistance to salts, alkalis, aggressive acids and drains. An example is the salt that is sprinkled on snow in winter on the streets to melt.
The resistance of bitumen is reduced by organic solvents, oils and fats, from light, heat and air oxygen, which oxidize their constituent parts. When heated, soft particles evaporate and the surface of the bitumen hardens.
Their advantages are low flammability, that is, this material is not flammable. Petroleum bitumens are not hazardous to health and are not classified as such. Their other properties include thermal viscosity, high thermal insulation, and good wetting.
The hardness of bitumen is established by the depth of penetration of the needle immersed in them (it is measured in hundredths of a millimeter) at a normalized load for a certain time under conditions of a specific temperature. The transition between the solid and liquid state in them has a sliding character and is determined by the softening point at low temperatures. In addition, they are characterized by the so-called point of failure - this is a term denoting the temperature at which the bent layer of bitumen cracks or collapses.
Other materials
What other organic binders can you name? Coal tar pitch, which is a viscous or solid black substance and serves as a tar distillation product, is impregnated with roofing paper. This material is quite hazardous and may cause burns if it comes into contact with the skin. It is best to work with it in cloudy weather or in low light.
Coal tar is a substance released as a by-product during coke production. It has found its way into roofing mastic and road construction.
Lesson number 13
Mineral binders are used as masonry and plaster mortars. Depending on the possible conditions for the formation of the structure of an artificial stone, air is emitted in them (air lime, gypsum, magnesian binders - the formation of an artificial stone occurs in a dry environment) and hydraulic - they have a more complex composition, an artificial stone is formed and stored both in dry and in a humid environment (hydraulic lime and cements: Portland cement, slag Portland cement, special cements).
In most cases, a mixture of a mineral binder, water and aggregate is used in construction. The need to use a placeholder is due to two main reasons:
1) binders mixed only with water during hardening have an increased tendency to swell and shrink, which leads to the formation of cracks and destruction of structures. Aggregates reduce shrinkage;
2) the use of aggregates reduces the consumption of the binder and, consequently, the cost of the structures.
A mixture of binder, water and fine aggregate (sand) is called mortar, and a mixture of binder, water, sand and coarse aggregate (crushed stone, gravel) is called concrete.
When assessing the quality of mineral binders, the following main indicators are considered.
1. Grinding fineness (dispersion) is determined by sieving a weighed portion of the binder through a sieve with a standard mesh size and is characterized by the residue on the sieve (in% of the sample mass). In addition, the fineness of grinding is estimated by the specific surface of the powder.
2. Water demand is the amount of water in% by weight of the binder required to obtain a standard consistency of dough. For different binders, the methods for assessing the consistency are different, which is explained by the unequal methods of laying mixtures in production conditions. The use of a standard consistency dough provides comparable conditions in determining the setting time, strength and other properties of binders. The setting time shows how quickly the binder dough loses its plasticity, becoming tough and unprocessed. The beginning and the end of the setting are determined to a large extent conditionally by the time change in the depth of penetration of the needle of the Vic's device into the dough of standard consistency.
3. Strength - this is the main characteristic of the quality of binders, according to which their brand is established. Since the strength of binders changes over time, the brand is based on the strength achieved in a certain time during hardening under the conditions fixed in the corresponding standard. For binders hardening at different rates, the brand is controlled at different ages: for gypsum binders - after 2 hours of hardening in air, and for Portland cement - after 28 days of exposure to humid conditions.
Air lime is a local astringent. It is obtained by roasting at a temperature of 1000-1200 ° C of calcium-carbonate rocks (limestone, chalk, etc.), containing no more than 8% of clay impurities. Air lime can be released in the form of lumps of white or gray color and is called lump; or, if lump lime is crushed, ground lime is obtained. Air lime can be converted into a powdery state by slaking. Slaking of lime proceeds violently, with the release of heat and the formation of calcium hydroxide according to the reaction:
CaO + H 2 O = Ca (OH) 2 + 15.5 kcal.
If we take 40-70% of water by weight of lime for slaking, then a fine powder is obtained, which is called hydrated lime.
Depending on the content of active Ca and Mg oxides and non-extinguished grains, air and hydrated lime is divided into two grades: I and II. For air lime, the content of oxides should be at least 70% for grade I and 52% for grade II, and for hydrated lime, respectively, 55% and 40%.
Lime is used for the preparation of mortars for masonry and plaster, for the production of silicate bricks and mixed cements.
Construction gypsum(outdated name - alabaster) is obtained by firing two-water gypsum stone at a temperature of 120-170 ° C. As a result of firing, hydration occurs and the dihydrate gypsum stone passes into a semi-aqueous state according to the reaction: 2 (CaSO 4 * 2H 2 O) = 2 (CaSO 4 * 0.5H 2 O) + 3H 2 O.
Plaster of paris is a fast-hardening binders - the beginning of setting is 4-6 minutes, and the end is 30 minutes. Plaster of paris is divided into three grades: I, II and III. For grade I, the fineness of grinding should be no more than 15%, for grade II - 20% and for grade III - 30%. The ultimate compressive strength is 5.5 MPa, 4.5 MPa and 3.5 MPa, respectively. Stucco is used when plastering rooms and obtaining dry gypsum plaster, partition plates.
Forming gypsum differs from building plaster in finer grinding and higher strength. The setting time of the molding plaster should be at least 30 minutes. Molding plaster is used for sculptural and stucco works, making molds for the ceramic industry.
Anhydrite cement is obtained by firing a two-water gypsum stone at a temperature of 600-700 ° C and subsequent grinding with the addition of lime and slag and other hardening activators. According to the ultimate compressive strength (MPa), it is divided into four brands, 10, 15, 20. It is used for masonry and plastering of internal walls and the manufacture of art products.
The disadvantage of gypsum binders is their low water resistance, i.e. they can be used in rooms with a humidity of no more than 60-70%. Therefore, more resistant gypsum binders have been developed, these include polymer gypsum and gypsum-cement-pozzolanic binders.
Polymergypsum is obtained by mixing stucco with phenol-furfural resin (17-20%). This material, unlike stucco plaster, has a high compressive strength of -30 MPa and high water resistance. It is used in the production of facing tiles, as well as for finishing work in rooms with high relative humidity.
Magnesia binders substances are obtained by firing magnesite (MgCO 3) or dolomite (CaCO 3 MgCO 3) at a temperature of 800-850 ° C. The calcined product is respectively called caustic magnesite or caustic dolomite. Magnesian binders adhere well to wood, asbestos and other fibers and are used to obtain heat-insulating materials (fibrolite), warm floors (xylene). Magnesian binders are mixed not with water, but with solutions of salts of magnesium chloride and sulfate. The beginning of the hardening of this material no earlier than 20 minutes and no later than 6 hours. Magnesian binders have a high compressive strength of 40-60 MPa. The disadvantage of the material is its low water resistance, so it is used only in dry conditions.
Portland cement- the main type of hydraulic binders. It is a fine gray powder with a greenish tint. It is obtained by grinding a mixture of limestone (calcium carbonate) 75% and 25% clay, fired before sintering at a temperature of 1450 ° C. Portland cement with the required properties can be obtained when the content of basic oxides is in the following quantities: CaO - 60-67%, SiO 2 - 12-24%, Al 2 O 3 - 4-7% and Fe 2 O 3 -2 -6%. Harmful impurities are MgO and SO 3, the content of which, respectively, is allowed no more than 5 and 3.5%. Their increased content causes an uneven change in volume during solidification and increases sulfate corrosion.
According to the compressive strength at 28 days of age, cement is divided into grades: 400, 500, 550 and 600. The beginning of setting of the Cement should come no earlier than 45 minutes, and the end - no later than 10 hours from the start of mixing. The residue on sieve no. 008 should not exceed 15%.
Slag Portland cement is Portland cement (20-85%) with slag additives (15-80%). Its properties are similar to Portland cement, but it is cheaper. Available in three grades: 300, 400 and 500.
Liquid glass Is an aqueous solution of sodium silicate, made by firing a mixture of quartz sand and soda. The obtained glass after crushing is dissolved in water.
In construction, liquid glass is used to protect foundations from groundwater, waterproofing walls, floors and ceilings of basements, and arranging pools. It is well suited for gluing and bonding building materials, making acid-resistant, fire-resistant and refractory silicate masses. It is fashionable for them to glue paper, cardboard, glass, porcelain, impregnate fabrics, paper, cardboard, wood products to give them greater density and fire resistance. Liquid glass is successfully used for the manufacture of silicate paints and adhesives.
Astringent materials (mineral binders) are powdery substances that, after mixing with water, are capable of changing from a viscous (pasty) state to a stone-like state. The richness of mineral resources of our country, a relatively simple production technology and high construction and technical properties of mineral binders provide them with unlimited use in finishing work for the preparation of plaster solutions and other types of work.
Depending on the ability to harden in air and in water, binders are divided into two groups: air and hydraulic. If a binder can harden, maintain its strength for a long time, or increase it only in air, then it is called an air-hardening binder. A binder capable of hardening, maintaining and increasing its strength not only in air, but even better in water or in humid conditions, is called a hydraulic hardening binder.
Clay- the cheapest and most common binder. Bulk density - 1500-1700 kg / m3. Clay was formed as a result of the weathering of rocks. Depending on the impurities, clays are divided into oily, medium and skinny. The fewer impurities, the fatter it is. The main mineralogical composition is kaolinite. Clay is used for the preparation of pure clay mortars and as an additive in cement mortars for better plasticity and workability. If the clay is heavily contaminated, it is filtered and tortured. In this case, large particles settle during the mixing of clay with water, the water is drained, and a creamy mass (clay dough) is used in construction work.
Building lime there are several varieties:
Ground quicklime;
Lime dough;
Hydrated lime (fluff).
The raw material for the listed varieties of lime is lump quicklime (), which is formed as a result of heat treatment of limestone rocks ():
When ground into a fine powder, ground quicklime is obtained. When slaking lump lime with excess water, a lime dough is obtained, and when slaking lump lime with a limited amount of water, hydrated lime is obtained in the form of a fine white powder (fluff lime).
The lime slaking process is exothermic, i.e. heat is generated:
This reaction is very violent. Hence the name - boiling pot.
The term "fluff" arose in connection with the fact that a very porous lump of lime under the influence of a certain amount of water crumbles into a fine powder. The calcium oxide hydrate separated from the solution envelops the quicklime particles, and the quenching process is suspended. Therefore, continuous stirring is necessary for complete slaking of lime. Located in the plaster layer, it reacts with carbon dioxide from the surrounding air:
The process of formation of calcium carbonate () occurs only in air, proceeds slowly and is accompanied by the release of water. Thus, as a result of a number of chemical and technological transformations, limestone is again formed in the form of a layer of plaster of a given shape and texture.
Building plaster. Sulphate limestone is a natural raw material for production of plaster of paris. Gypsum (sulphate limestone) dehydrates when heated. It gives off water easily and does not require a lot of heat, as for lime production. When heated to a temperature of 800 "C, calcined gypsum is obtained, which quickly sets. The setting process (hardening) is determined by the fact that the substance to be mixed has a greater solubility than the product formed as a result of the interaction of the binder and water. Therefore, a new amount of hemi-aqueous gypsum passes into the solution, again a supersaturated solution is formed, from which gypsum crystals stand out:
The process of curing binders is the following sequence: dissolution - hydration - colloidation - crystallization.
Hydraulic curing binders(cements) - a product of fine grinding of pre-fired natural raw materials - marl or a mixture of limestone and clay in a ratio of 1: 3. They have the ability, after mixing with water, under the influence of physicochemical processes, to pass from a pasty state to a very strong stone-like state.
The main binder of hydraulic hardening is Portland cement... This binder has a complex polymineral structure, consisting mainly of compounds of four oxides:
The material formed after firing at a temperature of 1450 ° C is called clinker. After firing, the clinker is kept in special warehouses for two to three weeks to extinguish the free lime and then ground in special ball mills. The resulting green fine powder with a bulk density of 1200-1400 kg / m is Portland cement. The strength (grade) of Portland cement is determined by compression until the destruction of a standard cube sample after 28 days. from the moment of sample manufacture in kilograms per square centimeter (kg / cm) or megapascals (MPa). Portland cement grades: 200 (20 MPa); 300 (30 MPa); 400 (40 MPa); 500 (50 MPa); 600 (60 MPa); 700 (70 MPa). Low-grade cements are used for plastering work.
Pozzolanic Portland Cement is obtained by joint fine grinding of Portland cement clinker, gypsum and active mineral additives (tripoli, pumice, tuff, track, pozzolana). Pozzolanic Portland cement has grades 200, 250, 300, 400, 500. In addition to these, cements are produced: Portland slag cement, colored, expanding, hydrophobic, acid-resistant, etc.
Astringent building materials or simply binders are called natural or artificial substances that have the ability, as a result of physicochemical processes, to pass from a liquid or pasty state to a stone-like state, while simultaneously developing their adhesion to other materials.
Classification of astringent building materials
Astringents are classified into two main groups:
- inorganic or mineral binders (lime, gypsum, cement, etc.);
- organic binders (bitumen, tar, glue, etc.).
Inorganic binders materials, in turn, are divided into air and hydraulic.
Air binders materials harden only in air; hydraulic hardens both in air and in water.
When hardening inorganic binders, two stages are distinguished: setting - the process of gradual transition of a dough consisting of a binder and water from a fluid phase to a solid phase and hardening itself, in which the material, while remaining outwardly unchanged, gradually becomes more and more durable.
All inorganic binders are made from common nonmetallic minerals. However, they differ significantly in cost, which is explained by the different complexity and energy consumption of the process of their manufacture.
Air binders
Air binders include:
- lime,
- gypsum,
- soluble glass and
- acid resistant cement.
Lime- the simplest and most ancient binder - is obtained by burning limestone. As a result of firing, anhydrous calcium oxide - CaO - quicklime is obtained, which is quenched with water to obtain a building binder. At the same time, a large amount of heat is released, causing the temperature to rise to 300 °.
Hardening of lime proceeds with the addition of carbon dioxide from the air, which determines its property to harden only in air. The low content of carbon dioxide in the air causes a very slow hardening of lime, which lasts for years in very thick walls, and therefore the strength of building lime is not regulated.
Gypsum binders obtained by firing natural gypsum stone (gypsum dihydrate). As a result of firing, gypsum dihydrate loses 75% of water and turns into the so-called semi-aqueous gypsum, which, when mixed with water, quickly sets in crushed form and then hardens in air. The setting of gypsum proceeds so quickly that SNiP limits the time not only for the end, but also for the beginning of setting (4 minutes from the beginning of mixing).
This property of gypsum is known to be widely used in medicine in the treatment of fractures.
The compressive strength of the stucco is 35-45 kg / cm2.
However, gypsum has insufficient water resistance, expressed in a decrease in strength when wetted, and therefore it is used only for internal work (for partitions, plaster) in dry rooms, and also as an additive to other binders to accelerate the setting.
Soluble, or "liquid" glass is a silicate material specially manufactured at glass factories in the form of glassy lumps, which can be dissolved by steam (in autoclaves) or hot water to the required consistency. Dissolved glass is an air-curing mineral adhesive.
Liquid glass is used for the manufacture of fire retardant paints, acid-resistant putties and films, as well as for strengthening weak sandy soils.
Acid Resistant Silica Fluorosilicon Cement(CC) is a powdery mixture of ground quartz sand and sodium silicofluoride. The mixture, suspended on liquid glass, after hardening in air, turns into a strong stone-like body that can withstand the action of most acids.
Acid-resistant cement is used to protect building structures from acid corrosion, for the device of corrosion-resistant Iols, etc.
Hydraulic binders
The most common type of hydraulic binders are cements, and among them Portland cement is in the first place - an artificial binder obtained from natural marls or a mixture of limestone and clay.
The starting material is crushed, sealed with water and fired before sintering in rotary cylindrical kilns. The fired product (clinker) is ground in ball mills. The fine powder of light gray color obtained during grinding is cement.
Cement is the most versatile, but also the most expensive of the inorganic binders.
When cement is mixed with water in an amount of 20-50%, a cement paste is formed, which after some time sets, turning into a cement stone. The hardening of cement stone under favorable temperature and humidity conditions has been going on for many years. However, the strength grows rapidly only in the first time and therefore the period of 28 days (4 weeks) is taken as the standard cement hardening period.
Strength of cements characterized by their brands. To determine the grade of cement, standard samples are prepared in the form of beams measuring 4X4X16 cm (taking 3 parts of sand to 1 part of cement). The beams are tested for bending (until failure), and their halves are tested for compression.
The brand of cement is the numerical value of the ultimate strength in kg / cm2 when tested in compression. In addition, for each cement grade, the standard also establishes a minimum bending strength.
The cement industry now produces the main Portland cement grades 300, 400, 500, 600 and 700.
Ordinary Portland cement is used for concrete and reinforced concrete structures, with the exception of those exposed to the action of sea, mineralized or even fresh, but running water.
Other types of cement:
- Portland slag cement obtained by joint grinding of cement clinker with granulated blast-furnace slag (in the amount of 30-70%), which, being a waste of blast-furnace production, itself has binding properties;
- pozzolanic Portland cement, obtained by joint grinding of cement clinker with special dots, which, when cement hardens, bind free lime and thereby increase the resistance of concrete against leaching;
- alumina cement (grades 400, 500 and 600), characterized by particularly fast hardening; Unlike other cements, alumina cement reaches its grade strength within 3 days.
Expansion of the production of fast-setting cements is of great national economic importance, since it makes it possible to speed up and reduce the cost of the process of manufacturing precast concrete, as well as speed up the construction of monolithic reinforced concrete structures, since the speed of cement hardening determines the speed of concrete hardening.
Organic binders and materials based on them
Organic binders are divided into three main groups:
- bituminous,
- tar and
- synthetic.
All these materials are in the nature of resins - they soften and melt when heated.
Bitumen and tar are black or dark brown; therefore they are sometimes called black binders.
Natural bitumens as binders are found mainly in sedimentary rocks. Such rocks, when ground, melted and molded, are called asphalt mastic (asphalt).
Petroleum liquid and semi-solid bitumens are a product of oxidation of heavy residues of oil distillation.
Coal tar, a by-product of coal coking, is also available in liquid or semi-solid form.
Petroleum bitumen and coal tar are used to make roll roofing and waterproofing materials.
Roofing material is a flexible cardboard impregnated with bitumen. The covering roofing material (for the upper layers of the roof) has the same covering layer. The same material, only impregnated with bitumen (without a covering layer), is called lining roofing material (glassine).
Roll materials similar to roofing material and glassine, made on the basis of coal tar, are called tar and leather only, respectively.
Mastic is a mixture of bitumen or tar with fibrous or pulverized fillers (asbestos, wood flour, tripoli, quartz, etc.), which increase the heat resistance of the mastic and the consumption of the binder.
Distinguish between hot mastics, liquefied by heating, and cold, liquefied by solvents.
Bituminous and tar mastic is used for the construction of roll roofs made of roofing felt and roofing felt, as well as independently - for waterproofing.
Asphalt mastic is used for the construction of asphalt floors, sidewalks, road surfaces, etc.
Synthetic resins form the basis of plastics, which, due to their limited use in construction, are not considered here.