Mortars- these are mixtures of binder, water and fine aggregate, acquiring a stone-like structure as a result of the hardening process. Before hardening, they are called mortar mixtures and are used for masonry walls, foundations, and plastering the surfaces of various structures.
Based on the type of binders and additives, they are distinguished cement mortars, limestone, cement-lime, cement-clay and etc.
Based on the properties of the binder, solutions are divided on air, manufactured with air binders ( lime, plaster), And hydraulic- with hydraulic binders ( cement various types).
According to the type of fillers, they are distinguished heavy solutions- with natural sands and lungs with porous fillers.
The composition of the solutions is simple- with one binder(cement, lime) and mixed, which usually include two, less often three binders, or one binder with inorganic additive ( cement-lime, lime-clay and etc.).
Air mortars used for the construction of stone structures, operated in a dry environment, and hydraulic- in wet conditions.
Heavy solutions, where the filler is quartz sand, have a volumetric mass of more than 1600 kg/m3; lungs- less than 1500 kg/m3, the filler is sand made from expanded clay, ground slag, etc.
Strength solution determined by its brand (the numbers indicate compressive strength in kgf/cm2).
Waterproof solutions used to make structures waterproof (for example, cement mortar composition 1:2 with the addition liquid glass and etc.).

Composition of the solution

To prepare solutions use binding materials, fillers and additives.
TO binders includes puffed lime in the form of dough, fluff and quicklime; building gypsum, Portland cement and etc.
The filler for mortar mixtures is natural or artificial sand.

Air lime

Air lime It hardens only in air, which is why it is called air. She may be a quicklime lump ( lime-boiler), ground and slaked into powder ( fluff lime).
Quicklime- these are pieces of grayish color; ground- fine grayish powder.
Lime extinguished in an extinguishing box or barrel. In large quantities slaked lime stored in a creative pit dug in the ground and lined with boards. More often lime used as a test or fluff lime.

Construction gypsum

Construction gypsum It is rarely used in mortars, mainly for work in dry conditions, but as an additive to lime plaster mortars in large quantities. In lime mortars gypsum increases strength, reduces setting and hardening time.

Gypsum

Gypsum- This is a white or grayish finely ground powder. Sealed with water gypsum depending on the purpose, the beginning of setting is 2-20 minutes, the end of setting is 15-30 minutes or more. If necessary, you can extend the setting time gypsum, adding a retarder to it. As the latter, 5-20% lime paste, 5-10% borax, 0.5-2% flesh glue by weight are added to the mixing water gypsum. These additives help extend the setting time gypsum up to 40-60 min.

Portland cement

Portland cement is the most durable binding material. It has the following grades: 200, 300, 400 (the numbers indicate compressive strength in kgf/cm2). Portland cement is a grayish-green finely ground powder.
Grasping cement As a rule, it begins no earlier than 45 minutes and ends no later than 12 hours after mixing with water.
It must be taken into account that during storage cement its activity is falling by about 5% per month. Based on this, you should purchase freshly made, not stale cement. Its quality is determined visually by the sign of pelletization, by touch: if a handful cement clench in a fist, then freshly made cement it immediately wakes up between the fingers, and the stale one forms a lump, since it has already absorbed moisture. Until the lump can still be kneaded with your fingers, cement is considered suitable for consumption, but its dosage is usually increased by 20-50%.

Filler sands

Filler sands There are natural (heavy) ones - quartz, feldspathic or artificial.
The coarseness of the sand should correspond to the thickness of the seam and the nature of the masonry; Thus, for rubble masonry, sand with grains no larger than 5 mm is used, for brick masonry - no larger than 3 mm.
The grain size of the sand is approximately determined by touch. The grain size of coarse sand is more than 2.5 mm; medium - from 2 to 2.5 mm, small - less than 1.5 mm.
IN mortars fillers usually occupy 60-65% of the volume.
The permissible contamination of sand with clay and dust for solutions of grades 25 and 50 is no more than 10%, for a solution of grade 10 - up to 15%. If necessary sand washed.
As lungs fillers shell sands, granulated boiler and blast furnace slags, expanded clay are used sand.
Depending on density artificial sand divided into grades according to bulk density from 250 to 1100 (the numbers indicate the bulk density of sand, kg/m3).

Clay

It is introduced into lime and cement mortars as an additive in such quantities that the ratio cement : clay did not exceed 1:1 (by volume). The addition of clay improves the grain composition, increases water-holding capacity, improves workability, and increases the density of the solution.
Clay consists of different minerals, so it comes in different colors.
Distinguish skinny, medium and fat clay. Skinny is usually used in its pure form, medium in fat and fat is added to solution in smaller quantities.

Preparation of masonry mortars

Masonry mortar can be prepared in a concrete mixer with a capacity of 0.15 m3 or manually.
Cement mortar prepared as follows: in a metal or wooden box made of boards 25-30 mm thick with a bottom covered with roofing iron, dimensions 1 x 0.5 m or 1.5 x 0.7 m, height 0.2-0.25 m, first fill in the required number of buckets of sand pour a full bucket of cement on top in an even layer, then shovel the mixture until the mixture is uniform in color, then pour a measured amount of water from a watering can and continue shoveling until a homogeneous composition is obtained.
Cooked solution spend within 1.5 hours so that it does not lose strength. Sand For preparing the solution must first be sifted through a sieve with 10x10 mm cells ( for masonry).

The lime paste solution is prepared immediately, mixing it with sand and water until smooth.

Cement-lime mortar prepared from cement, lime paste and sand.

Lime dough diluted with water until milk is thick and filtered on a sieve with 10x10 mm cells. A dry mixture is prepared from cement and sand and mixed with lime milk to the required thickness (dough consistency).

Cement-clay mortar prepared similarly to cement-lime.

Compositions(in volumetric parts) cement, cement-lime, limestone And brands of solutions shown in table 12.

Table 1. Compositions of cement-lime, cement-clay and cement mortars for stone structures

Brand cement	Volumetric dosage (cement: lime or clay: sand) for mortar grades
	150	100	75	50	25	10
400	1: 0,2: 3 1: 0: 3	1: 0,4: 4,5 1: 0: 4,5	1: 0,5: 5,5 1: 0: 5,5	1: 0,9: 8	---	---
300	1: 0,1: 2,5 1: 0: 2,5	1: 0,2: 3,5 1: 0: 3	1: 0,3: 0,4 1: 0: 4	1: 0,6: 6 1: 0: 6	1: 1: 10,5 1: 1: 9	---
200	---	---	1: 0,1: 2,5 1: 0: 2,5	1: 0,3: 4 1: 0: 4	1: 0,8: 7 ---	1: 1: 9 1: 0,8: 7

Note:
Upper values ​​for cement-lime mortars, lower - cement-clay mortars. 0 - indicates the absence of this binder in the solution.

Table 2. Compositions of lime mortars

Requirement of cement per 1 cubic meter. sand or cement-lime or cement-clay mortar is given in table 3.

Table 3. Cement consumption, kg per 1 m³ of sand (mortar)

Cement brand	Brand of solution
	150	100	75	50	25	10
400 200	350 400	255 300	200 240 405 445	140 175 280 325	--- 155 190	--- 75 95

Note: Numerator - cement consumption per 1 cubic meter. sand. Denominator - 1 cubic meter. solution.

Materials Science

Lecture No. 7

Topic: Mortars

General information

Building mixture - artificial stone material obtained as a result of hardening of a mortar mixture consisting of a binder, water, fine aggregate and additives that improve the properties of the mixture and mortars. There is no coarse aggregate, since the mortar is used in the form of thin layers (masonry joints, plaster).

For the production of mortars, inorganic binders (cements, airborne lime and building gypsum) are often used.

Construction mortars are divided depending on the type of binder, density and purpose.

By type of binder There are cement, lime, gypsum and mixed mortars (cement-lime, cement-clay, lime-gypsum).

By density distinguish: heavy solutions with a density of more than 1500 kg/m 3, usually made on quartz sand; light solutions with a density of less than 1500 kg/m 3, produced on porous fine aggregate and with rock-forming additives.

By purpose mortar is distinguished: masonry – for masonry walls, foundations, pillars, vaults; plastering – for plastering interior walls, ceilings, building facades; assembly – for filling seams between large blocks and panels during the installation of buildings and structures from ready-made prefabricated structures and parts; special – solutions – decorative, waterproofing, grouting.

Materials for the production of mortar mixtures

Binders. Portland cement and Portland slag cement are used, the grade of cement is 3-4 times higher than the grade of mortar. Puffed lime in the form of lime paste is introduced into the mixer when preparing a mortar mixture; Ground quicklime is less commonly used. Construction gypsum is part of gypsum and lime-gypsum mortars.

Sands natural ones are used - quartz, feldspar, as well as artificial ones - crushed from dense rocks and porous rocks; from artificial materials(pumice, expanded clay, perlite). Porous sands are used to prepare light solutions. If the sand contains large inclusions (clumps), then it is sifted. For brickwork Use solutions on sand with grains of no more than 2 mm. For mortar grade M100 and higher, sands must meet the same requirements regarding the content of harmful impurities as sands for making concrete. For solutions of grade M50 and below, the content of dust particles up to 20% by weight is allowed by agreement of the parties.

Plasticizing additives. Most often, mortar mixtures are laid in a thin layer on a porous base capable of sucking out water (brick, lightweight concrete, cellular concrete). To maintain the workability of mortar mixtures when laid on a porous base, inorganic and organic additives are introduced into them, increasing the ability to retain water.

Inorganic dispersed additives consist of small particles that retain water well (lime, clay, thermal power plant ash, diatomaceous earth, ground blast furnace slag). Clay used as a plasticizing additive should not contain organic impurities and easily soluble salts that cause “discoloration” on building facades. Clay is introduced into the mortar mixture in the form of a liquid dough.

Organically esurfactant plasticizing and air-entraining additives: saponified wood pitch, rosin soap, soap (consists of sodium salts, is a pasty brown mass), LST and others are introduced in an amount of 0.1-0.3% by weight of the binder. They not only improve the workability of mortar mixtures, but also increase frost resistance, reduce water absorption and shrinkage of the mortar.

Hardening accelerators are added to mortars used for winter masonry and plastering, which lower the freezing point of the mortar mixture: calcium chloride, potash, sodium chloride, bleach.

Properties of mortars

Workability – This property of the mortar mixture is easy to lay in a dense and thin layer on a porous base and does not delaminate during storage, transportation and pumping with mortar pumps. It depends on the mobility and ability of the mixture.

Mobility mixtures is characterized by the immersion depth of a metal cone (weighing 300 g) of a standard device. Mobility is prescribed depending on the type and suction ability of the base. For brickwork, the mobility of the mortar is 9-13 cm, for filling joints between panels and other prefabricated elements - 4-6 cm, and for vibrating rubble masonry - 1-3 cm.

Water holding capacity – this is the property of a mortar mixture to retain water when laid on a porous base, which is necessary to maintain the mobility of the mixture, prevent delamination and good adhesion of the mortar to the porous base. Water-holding capacity is increased by introducing inorganic dispersed substances into the solution mixture. (consisting of small particles) additives and organic plasticizers. The mixture with these additives releases water to the porous base gradually, while it becomes denser, adheres well to the brick, making the masonry stronger. A workable mortar mixture is obtained if the grain composition of its solid components is correctly assigned, determined by the ratio of sand, binder and dispersed additive. The binder dough fills the voids between the sand grains and evenly covers the sand grains with a thin layer, reducing internal friction. The easy-to-place mortar mixture is convenient to work with, resulting in increased productivity. The quality of masonry depends on the workability of the mortar network. A properly selected mortar mixture fills unevenness, cracks, and depressions in a brick or stone, so a large contact area is obtained between the mortar and the brick (stone), as a result, the strength and solidity of the masonry increases. The durability of the walls increases.

The main properties of mortars are: strength (grade) for a given curing period, adhesion to the base, frost resistance and Deformation characteristics: shrinkage during hardening, affecting crack resistance, elastic modulus, Poisson's ratio.

Strength under compression is determined by testing cube samples with an edge length of 7.07 cm at the age specified in the standard or technical conditions for this type of solution. The production of samples from a mortar mixture with a mobility of less than 5 cm is carried out in conventional forms with a tray, and from a mixture with a mobility of 5 cm or more - in forms without a pallet, installed on a brick base (covered with newsprint moistened with water).

The strength of mixed mortars depends on the amount of lime or clay added to the solution. The optimal addition of lime or clay dough, which makes it possible to obtain workable mortar mixtures and dense solutions, corresponds to the maximum on the strength curves (see V.G. Mikulsky Construction Materials, p. 307 - graph of the influence of dispersed additives (lime, clay) on the strength of solutions of the composition ( cement: sand 1-1; 2-1:4; 4-1:6; 5-1:9) for mortar mixtures of different compositions - from fat 1:3 to “lean” composition 1:9 ; composition is indicated in volumetric parts - cement: dough: sand.

Based on the laws governing the strength of solutions, tables of recommended compositions of different brands have been compiled, which are widely used in practice.

Based on their strength at 28 days of age under compression, mortars are divided into grades: 4, 10, 25, 50, 75, 100, 150, 200. Mortars of grades 4 and 10 are made using air and hydraulic mixtures, etc.

Lowering the temperature slows down the growth of the strength of solutions.

Therefore, at low positive temperatures, the strength of the solution at the age of 28 days is 55-72% of the grade.

Therefore in winter time Solutions with chemical additives (potash, sodium nitrate) are widely used, which lower the freezing point of the solution and accelerate its strength gain. In winter, the grade of mortar for masonry (without greenhouses) and installation of large-panel walls is usually increased by one step compared to the grade for summer work (for example, 75 instead of 50).

Frost resistance a solution is characterized by the number of cycles of alternating freezing and thawing that standard cube samples with dimensions of 7.07x7.07x7.07 cm can withstand saturation with water (a decrease in the strength of the samples is allowed no more than 25% and a weight loss of no more than 5%).

Mortars for masonry of external walls and external plaster have frost resistance grades: F10, F15, F25, F35, F50, and the grade increases for wet operating conditions. Under such conditions, the solutions also satisfy higher requirements for frost resistance: F 100, F 150, F 200, F 300. The frost resistance of solutions depends on the type of binder, water-cement ratio, additives introduced and hardening conditions.

Types of mortars

For masonry For the external walls of buildings, mainly cement and mixed mortars (cement-lime and cement-clay) grades 10, 25, 50 are used, depending on the humidity conditions and the required durability of the building. In the laying of lintels, piers, cornices, and pillars, the grade can be increased to 100.

Vibrobrick panels are made using mortars of grades 75, 100, 150, prepared with Portland cement and Portland slag cement.

Mounting solutions to fill horizontal joints when installing walls made of lightweight concrete panels, they must have a grade of at least 50, and for panels made of heavy concrete - not lower than 100.

The minimum consumption of cement for mortars for various purposes, 75-125 kg/m 3 of sand, is accepted for underground masonry of buildings, depending on the relative humidity of the air in the premises, and for laying foundations - in accordance with soil moisture.

For masonry in damp soil and below the groundwater level, solutions based on Portland cement with active mineral additives or slag Portland cement are used (with a minimum cement consumption of 125 kg/m3).

Plaster solutions. For external stone and concrete walls Cement-lime mortars are used in buildings, and lime-gypsum mortars are used for plastering wooden surfaces in areas with a dry climate. Internal plaster of walls and roofings of a building at a relative air humidity of up to 60% is made from lime, gypsum, lime-gypsum and cement-lime mortars.

The mobility of plaster solutions and the maximum fineness of sand used are different for each layer of plaster. The mobility of the solution for the preparatory layer when applied mechanically is 6-10 cm, and with manual labor - 8-12 cm. The largest sand size should be no more than 1.2 mm. To increase the mobility of plaster solutions, hydrophobic-plasticizing additives are introduced.

The Knauf company (Germany) produces gypsum for the domestic market. plaster mixtures“Goldband” - for concrete and brick surfaces and “Rotband” - for plastering ceilings and walls made of any materials. These mixtures are distinguished by a complex of high technological and operational properties.

Decorative solutions intended for finishing layers wall panels and blocks, external and interior decoration buildings. These solutions are made using white, colored and ordinary Portland cement; Construction gypsum and lime are also used for colored plasters inside buildings. The filler is pure quartz sand or crushed sand from white limestone, marble, etc. For the front finishing layer of external wall panels (made of lightweight concrete), a mortar of grade 50 is used, for finishing reinforced concrete structures - 150 with a frost resistance of at least 35.

Waterproofing solutions for waterproofing layers and plasters, they are usually made with a composition of 1:2.5 or 1:3.5 (cement: sand by weight) / cements, sulfate-resistant Portland cement.

Portland cement, expanding

Injection cement mortars used for filling channels in prestressed structures and compacting concrete. The grade of the solution must be at least 300, so Portland cement grade 400-500 is used.

X-ray protective solution prepared on barite sand (BaSO 4) with a maximum particle size of 1.25 mm, using Portland cement or Portland slag cement. Additives containing light elements are added to it: lithium, boron, etc.

Dry mixes

Construction dry mixtures are factory-made compositions based on mineral binders, including fillers and additives. In some cases, water-soluble or water-emulsifying polymers can be used as a binder. To the place of production construction work dry mixtures are delivered in packaged form, and to use them for their intended purpose, you just need to add the required amount of water.

Dry mixes compared to commercial and concrete mixtures have a number of advantages: reducing the number of technological operations to convert dry mixtures into working condition; improving the quality of construction work due to factory preparation of mixtures; reduction of transport costs by 15%; reduction of solution waste by 5-7% as a result of batch preparation; increase in labor productivity by 20-25% due to increased plasticity of solutions.

Currently, dry mixtures are one of the areas of technical progress in construction; they are used as masonry, installation and plaster mortars, putties, tile adhesives, compositions for self-leveling floors, and repair compositions.

Materials used for dry mixtures. Powdered mineral binders are used as binders: Portland cement, building gypsum, puffed lime. In some cases, powdered polymers are used as a binder, which dissolve in water or form emulsions (cellulose ethers, polyvinyl acetate, acrylates).

Sand for construction work with an elastic modulus of 1-2 is widely used as a filler, and the small grain size should not exceed 1.25 mm. For light solutions, porous expanded sands (perlite, vermiculite, expanded clay) are used. For putties, lime flour and powdered chalk are used.

Additives play a big role in the preparation of dry mixtures. Since mortar mixtures prepared from dry mixtures are laid, as a rule, in a thin layer on porous bases, inorganic and organic plasticizing additives are used to ensure plasticity and water-holding capacity: clay, puffed lime, thermal power plant ash, superplasticizer S-3.

To increase adhesion (adhesion of surfaces of dissimilar bodies), crack resistance and impermeability, polymer additives are introduced into the composition of dry mixtures, which, as mentioned above, must be in powder form, be water-soluble or form emulsions with water.

To carry out work at subzero temperatures, antifreeze additives are added to the dry mixtures: potash, sodium nitrite, calcium formate. At the same time, special requirements are placed on the hygroscopicity of additives. (ability to absorb moisture from environment) .

Water for mixing dry mixtures should not contain harmful impurities.

The quality indicators of dry mixtures must correspond to the area of ​​application of the mixture. If the dry mixture is used as a masonry mortar, then it must have the following set of quality indicators: plasticity, water-holding capacity, compressive strength, frost resistance.

Depending on the purpose of mortar mixtures, their production is carried out in a factory using a set of equipment that is equipped with concrete mortar units. The technology for the production of dry mixtures consists of the following technological operations: sand or gravel-sand mixture supplied from a quarry is subjected to heat treatment in drying units, where their humidity is brought to 0.5%, then sieved on sieves to the required fractions. After dosing, the sifted sand is sent to a forced mixer. After dosing, the sifted sand is sent to a forced mixer. Other components are loaded into the same mixer in the required quantities. The dosed materials are mixed until a homogeneous mass is obtained. The resulting mixture is packed into containers required for sale and delivered to the finished product warehouse. If packaging is not provided, the mixture immediately enters the finished product storage bin. This technological scheme for producing dry mixtures is carried out using sands of fine and very fine fractions. Mixtures are stored in a dry place, and modified polymers are stored at a temperature not exceeding 40 0 ​​C.

Abstract >> Transport

Location of tanks in form Latin letter N ( view side). For... The shape of the tank is determined by the load capacity, view and the properties of the cargo, unloading... transportation of various construction solutions And their portioned dispensing for construction objects. Tank...

Preface

Construction mortars and mastics – necessary materials for facing and other construction works.

Contents

Mortars and mastics are necessary materials for facing and other construction work. The main types of mortars include mortars for floor screeds, filling joints, and layers of mosaic floors. There are also special solutions for waterproofing. Below is information about the composition of each of them and the main characteristics of solutions and mastics.

Groups of mortars and mastics

Building mixture- This is a mixture of inorganic binder, fine aggregate and water selected in a certain way. In certain cases, inorganic or organic additives are added.

Construction mortars are divided into the following groups:

• heavy, average density which in a dry state are more than 1500 kg/m3 (quartz sand is used in production);
• lightweight, the average density of which in a dry state is less than 1500 kg/m3 (light porous sand is used in production).

Based on the type of binders included in the solution, the following groups are distinguished: cement, lime, gypsum and complex (cement-lime, cement-clay, lime-gypsum, etc.).

By name, three groups are distinguished: masonry, finishing and special.

Mastics consist of an adhesive composition and a solvent with the addition of finely ground natural or polymeric materials.

Mastics are hot and cold. Hot mastics are used in a heated molten state, cold ones do not require preheating.

The thickness of the mastic layer is 0.5-5 mm, and the mortar mixture is 15-20 mm.

Water used for preparing solutions and aqueous mastics should not contain mechanical, chemical or other impurities that interfere with or slow down the hardening of the binder. As a rule, ordinary drinking water is used, as well as natural water with a pH value (water reaction) of at least 4 and no more than 12.5 (at pH 7, the water reaction is neutral, pH<7 - кислая, pH >7 - alkaline).

Basic properties of mortars

Workability- the ability of the mortar mixture to be laid on the surface in a thin layer. This is one of the main properties of mortars depending on the mobility and water-holding capacity.

Mobility of the mortar mixture (consistency)- the ability to spread under the influence of its own mass or external forces applied to it. It is determined by immersing a standard cone whose mass is 300 g in a solution. Marks must be placed on the outer surface of the cone every 10 mm. The cone is lowered into the freshly prepared solution, where it sinks under the influence of its own weight. The immersion depth of the cone, expressed in centimeters, characterizes the degree of mobility of the solution.

Water holding capacity- this is the property of all types of mortars to retain water when laying it on a porous base and not delaminate during transportation.

To increase properties such as mobility and water-holding capacity in mortars, organic plasticizing and inorganic disperse additives are introduced into the composition. Organic additives include soap naft and wood pitch, inorganic additives include lime, clay, ash, etc.

Layering properties of the mortar mixture– its heterogeneity in thickness, which occurs during storage, transportation or vibration of the mixture.

Strength. Depending on the tensile strength, the compressive strength of prepared samples in the form of a cube determines the brand of solution. The average tensile strength value is calculated as the arithmetic mean of the test results of 5 samples. The loss of strength when testing samples for frost resistance should not exceed more than 25% with a weight loss of no more than 5%.

Depending on the number of cycles of alternating freezing and thawing maintained, the grade of the solution for frost resistance (MRZ) is determined.

Cement mortars for floor screeds and filling joints between tiles

Floor screeds are layers that form a rigid or dense crust over non-rigid or porous elements of the floor or ceiling. Screeds are installed either to level the surface of the floor or ceiling, or to give the coating the required slope.

Screeds can be concrete or mortar. The strength grade of cement mortars for floor screeds is established by the project, but must be at least 150. The mobility of mortars for floor screeds is 4-5 cm.

The grade of cement mortar for filling joints between tiles must be at least 150. The mobility of the mortar is 5-6 cm.

Sand should not contain more than 3% by weight of dust and clay particles. The use of Portland cement and aluminous cement is allowed. It is also recommended to add surfactants to cement mortars for filling joints. The water-cement ratio of the solution should not go beyond 0.45-0.5.

Compositions of cement mortars and dry cement mixtures

Table “Composition of cement mortar and its application”:

Composition of the solution by weight (water: cement: fine-grained sand) or with a cement grade of at least 400	Brand of solution	Application of the solution
		For interlayers and filling joints in coatings made of piece materials
		For coatings
		For screeds

For facing works in which cement mortars are used, it is advisable to use dry cement mixtures. Solutions are prepared on site in the required quantities and taking into account the exact dosage, which significantly saves materials and prevents losses.

Table “Composition of dry cement mixtures for facing work”:

Brand of solution	Cement brand	Composition by weight (cement: sand)	Material consumption per 1 ton of mixture, kg
			cement	sand

The dry mixture for the preparation of colloidal cement adhesive KCK consists of Portland cement (grade 400) and quartz sand, with a ratio of these substances of 7: 3 by weight. SSB should be used as a plasticizing additive.

KCK adhesive is used for finishing finished reinforced concrete products with a textured layer based on white and non-ferrous metals with marble chips and chips from other natural stone materials. To avoid microcracks in the textured layer, during the preparation of the solution, 1.5 parts of sand by weight are added to 1 part of dry CCC.

The dry mixture is mixed with water immediately before use.

The adhesion strength of KCK glue to the base reaches 3 MPa, and when compressed at 7 days of age - 55 MPa.

Composition of solutions for layering floor screeds and mosaic coverings

Mortars for layering screeds and mosaic mosaic (terrazza) coatings are made from white or bleached ordinary cement, and in the production of colored coatings pigments are added in an amount of no more than 15% by weight.

For ordinary cement, stone powder made from white or light-colored stone materials can be used as a whitening agent. The particle size in the mosaic mortar should not exceed 0.15 mm, and the compressive strength should not exceed 20 MPa. The amount of whitener should not be more than 20-40% by weight of cement.

Table “Composition of mosaic mortar for flooring”:

Brand of solutions	Composition by weight (water: cement: sand: crumbs) depending on the grade of cement
	0,55: 1: 2,3: 3,9	0,57: 1: 2,8: 4,8	0,77: 1: 3,2: 5,5
		0,5: 1: 2,2: 3,8	0,6: 1: 2,6: 4,5; 0,45: 1: 2: 3,5

Gypsum and lime are not used as cement whiteners. The grade of whitened cement should not be lower than 300.

Sand and chips (fine crushed stone) used in solutions for mosaic floors are made from polished hard rocks (marble, granite, basalt). The compressive strength of these substances must be at least 60 MPa. The crumb size should not exceed 15 mm and 0.6 times the thickness of the mosaic coating.

The mobility of the mosaic mortar when laying is 2-4 cm. The grade is adopted according to the project, but should not be lower than 20 MPa.

The color, tone and strength of the selected compositions are tested on prototypes.

Table " Specifications colored mosaic compositions":

Materials	Composition by weight		Compositions of colored and bleached cements, %
Composition imitating red granite
Colored cement			Pozzolanic Portland cement - 75 Iron minium- 4 Mummy light - 2 Marble powder - 19
Red granite chips, 5-6 mm in size
Labradorite crumbs 5-6 mm in size
Composition imitating gray granite
Cement diluted			Portland cement - 80 Marble powder - 20
Crushed stone and sand from dark gray granite with a particle size of 6-15 mm
Labradorite chips, 6mm size

Acid-resistant solutions based on liquid glass and their composition

Solutions based on liquid glass are used in cases of exposure to oils and aggressive acids on the surface of the cladding. Such solutions are not waterproof, so hardening must take place for at least 10 days in dry conditions without contact of water or acids with the surface.

Acid-resistant solutions consist of sodium silicofluoride, fillers and liquid glass. Finely ground or dust-like acid-resistant materials are used as fillers (for example, diabase, andesite, beshtaunite, granite, clinker, etc.). The compressive strength of aggregates should not be lower than 80 MPa, acid resistance should not be lower than 94%, humidity should not be more than 2%. In solutions with liquid glass, the use of ground quartz sand, natural dusty quartz and acid-resistant cement is allowed.

Sodium silicofluoride must be finely ground. Humidity should be less than 1%, and Na2SiF6 content should be more than 93%.

The acid-resistant solution is sealed with liquid glass, the density of which is 1.36-1.45 g/cm3, and the modulus is 2.31-3. It is allowed to use liquid glass made from silicate blocks. The mobility of the solution is 2-4 cm.

Table “Composition of acid-resistant solutions for interlayers and filling joints in coatings made of piece materials (% by weight)”:

Materials	Compositions
Liquid sodium glass
Sodium silicofluoride
Mineral powder (beshtaunite, andesite flour)
Acid resistant cement
Brick dust or crushed glass

Additives to cement mortar for surface waterproofing

To install cement waterproofing, cement mortar is used with the addition of chemical sealants or hydrophobic additives (such as bitumen emulsions, ceresite, sodium aluminate, organosilicon compounds).

The grade of waterproofing solutions for cement surfaces must be at least 75 in strength and withstand the following: hydrostatic pressure: 1 hour after installation - 0.1 MPa, after 24 hours - 0.5 MPa. The mobility of the solution is 4-5 cm.

Table “Additives to cement mortar for waterproofing (parts by weight)”:

Components	Compositions
Sulfate-resistant Portland cement grade 400
Clay crumpled
Sodium aluminate

Bituminous hot and cold floor mastics

Bituminous floor mastics are used for installing floors made of piece materials (for example, ceramic tiles). Mastics are used to secure tiles and fill the joints between them.

Table “Composition of mastics for filling joints between ceramic tiles(parts by weight):

Components	Compositions
Portland cement grade 400
Natural drying oil
Fine sand (1 mm)

Table “Composition of hot bitumen mastics on black binders (% by weight)”:

Components	Compositions
Bitumen BN-70/30
Fine sand
Mineral powder (stone flour and other fine aggregates)
Asbestos 6th or 7th grade

Cold bitumen mastics are a colloidal solution of petroleum bitumen in an organic solvent (naphtha, kerosene, green petroleum oil, etc.).

Table “Composition of cold bitumen mastics (% by weight)”:

Components	Compositions
Lime-bitumen paste
Filler: ground limestone
Portland cement grade 400
asbestos 7th grade
fly ash from thermal power plant

Mastics based on synthetic resins and drying oils are used for fastening ceramic and glass tiles. They also serve as fillers for joints between tiles.

All are used for mortars inorganic binders. Type of binder assigned depending on the operating conditions of the structures and the brand of solution.

For above-ground structures at relative air humidity up to 60% and for foundations operated in low-moisture soils for low-grade mortars of grades 4 and 10, it is recommended air and hydraulic lime, lime-slag binders, romancement and cement for mortars. Lime-pozzolanic and lime-ash binders are allowed.

For solutions of grade 25 and higher, operated under the same conditions, you should use Portland cement, slag Portland cement, plasticized and hydrophobic Portland cements. Allowed pozzolanic Portland cement, mortar cement, lime-pozzolanic binder.

For ground structures operated at relative air humidity above 60%, and foundations located in very wet and water-saturated soils, grade 10 mortars are used lime-slag binder, roman cement and mortar cement. Allowed lime-pozzolanic and lime-ash binders, hydraulic lime, for grades 25 and above - Portland cement, slag Portland cement, pozzolanic, plasticized and hydrophobic Portland cements. Allowed lime-slag binder and cement for mortars.

For the installation of concrete panels and large blocks for mortars of grade 25 and higher should be used Portland cement, plasticized and hydrophobic Portland cement. Allowed slag Portland cement and pozzolanic Portland cement.

For structures erected using the freezing method, grade 10 mortar is recommended Portland cement and pozzolanic Portland cement, lime-containing binders are allowed. For solutions of grade 25 and higher should be used Portland cement, plasticized and hydrophobic Portland cement, slag Portland cement is allowed.

For structures operated in aggressive sulfate waters, it is necessary to use sulfate-resistant Portland cements, pozzolanic Portland cements are allowed.

For structures located in soft waters, solutions are prepared using pozzolanic Portland cements and slag Portland cements.

For the installation of a facing layer of large blocks and panels from mortars of grades 50 and higher should be used white and colored Portland cements, Portland cement and Portland slag cement are allowed.

For installing waterproofing plasters or shotcrete shells on reinforced concrete pipes, sealing joints of prefabricated structures, caulking socket pipes, sealing anchors, etc. for mortars of grade 50 and higher should be used expansive Portland cement, gypsum alumina and waterproof expansive cements.

For interior decoration of buildings, grade 25 and higher mortar is used gypsum binders grade G-3 and above and gypsum cement-pozzolanic binder, are allowed anhydrite binders. Fillers for heavy mortars are natural quartz or feldspathic sands, as well as crushed sands obtained from dense rocks. For light solutions, porous artificial sands are used: expanded clay, agloporite, from slag pumice, granulated slag, expanded perlite and vermiculite and natural sands from pumice, volcanic slag and tuff, from light carbonate rocks, diatomite, opoka, tripoli.

Masonry mortars for rubble masonry, installation of large-block and large-panel walls should be prepared on sand with the largest grain size not exceeding 5 mm, for brickwork - 2.5 mm.

Plaster solutions, used for spraying and soil, are prepared on sand with the largest grain size of no more than 2.5 mm, for covering - no more than 1.25 mm.

Water for mixing solutions should not contain harmful impurities. It is subject to the same requirements as .

To increase the mobility, non-segregation, and water-holding capacity of mortar mixtures, they are introduced into their composition.

Lime and clay dough serve as inorganic plasticizers. In simple solutions they are astringent, in mixed ones, their main purpose is to plasticize mixtures.

Soap naft, soapy liquor, soap stock waste, technical lignosulfonates, etc. are used as organic plasticizers. Soap naft is a by-product of alkaline refining of petroleum products. Consists of sodium naphthenic acid soaps, easily soluble in water. Soaped lye is a by-product formed during cooking laundry soap. Consists of saponified fatty acids. Soap stock waste is generated in soap factories. They consist of 10 to 45% saponified fatty acids.

Organic plasticizers are introduced in an amount of 0.03-0.3% by weight of cement into cement and cement-lime mortars. They replace partially or completely lime dough. It should be borne in mind that their use in cement mortars reduces the design resistance of the masonry by 10%.

In solutions for winter work enter .

K category: Selection of building materials

Mortars

Mortars are mineral mixtures that harden and bond firmly to the stone. The solution must contain a binder (cement, gypsum or lime), aggregate (gravel or sand) and clean water.

Depending on the purpose and use of mortar additives, the following solutions are prepared:
1. Construction, for bricklaying.
2. Plastering.
3. Plaster.
4. Cement.

The mortar for masonry should consist of sand and lime in a ratio of 3: 1 or 4: 1. 1 or 2 shovels of cement can be added to the mortar. This is especially necessary when constructing walls that bear a special load. Sand and cement in this case are mixed in a ratio of 3:1 -6:1.

To prepare the plaster mortar, you can use both hydraulic lime and air lime. It also contains sand. There is a difference between plaster mortar for external work and plaster mortar for internal work.

In the first case, hydraulic lime and sand are taken in a ratio of 1:3; air and lime - 1: 2. In the second case, hydraulic lime and sand are mixed in a ratio of 1: 5, and air lime - 1: 3.

Gypsum mortar differs from cement and lime mortar in its high strength and ease of preparation. To do this, all you need to do is take a container, pour it into water, pour in the plaster and mix everything thoroughly so that there are no lumps, which could later cause cracks to appear. Dilute the plaster with water immediately before working with it, because it may thicken ahead of time, then you will not be able to work with it. To prevent this from happening, you can mix a little sifted sand (2:1) into the plaster, but be aware that this will significantly reduce the strength of the gypsum.

Cement mortar is necessary for the preparation of durable plaster. To do this, take pure cement and water in a ratio of 1: 2 (1: 3).

Mortar additives are necessary to improve the quality of solutions. They significantly improve the physical and mechanical properties of solutions, their color, and frost resistance.

When coloring solutions, in addition to the usual additives, you can only use paints of bright colors that do not contain gypsum and barite impurities. Frost resistance is achieved by adding chlorides to the solution. They allow you to work with the solution at fairly low sub-zero temperatures. Chlorides and other means of protecting against exposure to low temperatures are used with the utmost caution, because an overdose of substances, as a rule, leads to the formation of unsightly smudges.

Construction mortars are characterized by three main parameters: density, type of binder and its purpose.

Depending on the density (in a dry state), heavy (density 1500 kg/m3 or more) and light (density less than 1500 kg/m3) solutions are distinguished. To make heavy solutions, heavy quartz or other sands are used; fillers in light solutions are light porous sands made from pumice, tuff, slag, expanded clay, etc. Light solutions are also obtained using foaming additives - porous solutions.

Based on the type of binder, construction mortars are divided into cement (based on Portland cement or its varieties), lime (based on air or hydraulic lime), gypsum (based on gypsum binders) and mixed (based on cement-lime, cement-clay, lime-gypsum binders) . Solutions prepared with one binder are called simple, and solutions prepared with several binders are called mixed (complex).

According to their intended purpose, mortars can be masonry (for masonry, installation of walls from large-sized elements), finishing (for plastering rooms, applying decorative layers to wall blocks and panels), special ones with special properties (waterproofing, acoustic, X-ray protective).

The choice of binder depends on the purpose of the solution, the requirements for it, the temperature and humidity conditions of hardening and the operating conditions of the building. Portland cements, pozzolanic Portland cements, slag Portland cements, special low-grade cements, lime, and gypsum binders are used as binders. To save hydraulic binders and improve the technological properties of mortars, mixed binders are widely used. Lime in mortars is used in the form of lime paste or milk. Gypsum is mainly used in plaster solutions as an additive to lime.

Water used for solutions should not contain impurities that have an impact bad influence for hardening of the binder. Tap water is suitable for these purposes.

If the solution is used in winter conditions, hardening accelerators are added to its composition, as well as additives that reduce the freezing point of water (calcium chloride, sodium chloride, potash, sodium nitrate, etc.).

The composition of a mortar is indicated by the quantity (by mass or volume) of materials per 1 m3 of mortar or by the relative ratio (by mass or volume) of the original dry materials. In this case, the consumption of the binder is taken as 1. For simple solutions consisting of a binder (cement or lime) and not containing mineral additives, the composition is designated 1: 4, that is, for 1 mass part of cement there are 4 mass parts of sand. Mixed solutions, consisting of two binders or containing mineral supplements, denoted by three numbers, for example 1:3:4 (cement: lime: sand).

The quality of mortar mixtures is characterized by their workability - the ability to be laid without special compaction on the base in a thin layer, filling all its unevenness. Workability is determined by the mobility and water-holding capacity of mortar mixtures.

Mobility is the ability of a mortar mixture to spread under the influence of its own mass. Mobility is determined (in cm) by the depth of immersion in the mortar mixture of a standard cone weighing 300 g with an apex angle of 30° and a height of 15 cm. The deeper the cone is immersed in the mortar mixture, the greater mobility it has.

The degree of mobility of the mixture depends on the amount of water, the composition and properties of the starting materials. To increase the mobility of mortar mixtures, plasticizing additives and surfactants are added to them.

The mobility of mortars, depending on their purpose and method of installation, should be as follows.

Laying walls made of bricks, concrete stones, light rock stones: 9-11

Laying walls made of hollow bricks, ceramic stones: 7-8.

Filling horizontal joints when installing walls made of concrete blocks and panels; Joining vertical and horizontal seams: 5-7.

Rubble masonry: 4-6.

Filling voids in rubble masonry: 13-15.

Water retention capacity is the ability of a solution to retain water when laid on a porous base. If the mortar has good water-holding capacity, partial suction of water compacts it in the masonry, which increases the strength of the mortar. Water holding capacity depends on the ratio of the components of the mortar mixture. It increases with increasing cement consumption and frequent replacement! cement, the introduction of additives (ash, clay, etc.), as well as some surfactants. The strength of the hardened mortar depends on the activity of the binder, the water-cement ratio, the duration and conditions of hardening (temperature and ambient humidity). When laying mortar mixtures n; a porous base capable of intensively sucking out water, the hardening strength of solutions is significantly higher than the same solutions laid on a dense base.

The strength of the mortar depends on its brand, which is determined by the compressive strength after 28 days of hardening at air temperature; 5-25° C. The following brands of solutions are available: 4, 10, 15, 50, 75, 100, 150, 2t)0 and 300

The frost resistance of solutions is determined by the number of cycles of alternating freezing and thawing until the loss of 15% of the original strength (or 5% of the mass). PS frost resistance solutions are divided into Mrz grades from 10 to 300.

- Construction solutions