Technical characteristics of dry construction mixture M300 coarse-grained

CPS M300 is a universal sand-cement mixture that is very often used in various types of repair and construction work. This solution can act as durable concrete for pouring floors, foundations, certain structures, and can be used as plaster, masonry mixture, etc.

A variety of additives can be added to the M300 mixture to change certain characteristics and parameters of the solution, making it suitable for a variety of tasks. The use of dry sand concrete makes it possible to highly accurately predict the properties of the future solution, calculate the consumption of the product per square/cubic meter, and anticipate the completion time of the object.

The dry mixture produced in the factory, unlike the one prepared by hand, does not shrink and guarantees the presence of all the characteristics regulated by GOST. Preparation of the solution in this case requires a minimum of effort - just mix the mixture with water according to the instructions on the package.

In addition, such a solution, thanks to a clear calculation of the components, always turns out to be mobile, plastic, and comfortable to work with.

Composition of sand concrete M300:

• Portland cement grade M500 - up to 25% of the total weight of the mixture
• Fractional sand, crushed stone chips, granite screenings - up to 75% of the total mass
• Mineral additives (anti-frost, plasticizers, hydrophobic and others)
• Fiber fiber - only if addition is required by production

As a rule, a filler of two fractions is added to the M300 sand concrete mixture - medium-grained quartz sand 0.8-2 millimeters in size and large chips/screenings 4-8 millimeters in size. Thanks to these components, it is possible to obtain a durable solution that does not shrink, subject to minimal binder consumption. To create cheaper materials, it is allowed to use washed sand of 1-5 millimeters in size.

Types and areas of their use

Universal dry mixtures differ in composition and purpose, they have their own characteristics and characteristics.
You should pay attention to the marking, the number in which indicates the strength of the original product

M100

M100 products are intended for manual plastering and putty. The mixture is applied in an even thin layer, which leads to material savings. She is easy and pleasant to work with. The mixture retains its properties for two hours from the moment of dilution. Prices for M100 products are quite affordable.

M150

M150 products are the most popular of the varieties of universal mixtures. It is used in virtually all construction work using dry compounds. Unlike M300 and M400, it is used for masonry, plaster, and screed. Factory packaging is presented in 50 kg bags, less often they produce products in 25 kg packaging.

The universal mixture includes Portland cement, sand, mineral powder, plasticizers and other additives. The finished composition can only be diluted with cold water in the proportion indicated on the package.

M150 products are endowed with many advantages: they are reliable, frost-resistant, have good adhesion to various surfaces, high moisture resistance and vapor permeability. It is used in any climatic conditions.

The disadvantages of M150 include poor resistance to increased loads (no more than 150 kg per 1 cubic cm), therefore such a mixture is not used for work with the foundations of multi-story buildings.

The name “universal” speaks of the variety of applications of the M150 composition.

• The plaster mixture is designed for interior and exterior plastering work. Layer thickness can be applied up to 50 mm. After mixing, work should begin immediately: the mixture is in a pliable state for 2 hours. The plaster becomes completely dry and strong after 4 weeks.
• Using the M150 screed mixture, the floors in the rooms are leveled. Checking the level and setting the beacons, the floor is poured with a thickness of 1 to 10 cm. Thanks to the cement base, the floor acquires durable qualities that are resistant to temperature changes.
• The masonry mixture is used for laying gas silicate blocks and bricks of all types. M150 products can be used indoors and outdoors in cold or hot weather; weather conditions do not affect the quality of masonry. The dry mixture has proven itself well in rooms with high humidity.

M200

Product M200 is a masonry mixture. It consists of Portland cement, river sand and special additives. Designed for laying bricks, concreting flooring, constructing simple foundations, repairing walls and processing seams in concrete structures.

M200 can be used for laying garden tiles, as well as for plastering and puttying walls. It is available in bags weighing 50 kg.

M300

Sand concrete M300 appeared on the construction market not long ago, but has already gained popularity. Unlike the M150, it is designed for heavy loads. The products are durable and reliable, have a long service life, adapt well to weather conditions, are moisture resistant, environmentally friendly, and do not shrink. M300 consists of Portland cement, which contains gypsum, sand and crushed clinker. Products are packaged in 50 kg bags, less often in 200 kg bags for industrial scale.

Due to its special strength, the composition is used in all areas of construction work in all climatic conditions. During installation, they are used to install the foundation, floor screed, leveling walls and other surfaces. The product has proven itself well as a grout for cracks during work at emergency sites. The composition is used when laying garden paths, stairs, and borders. The mixture is used in the production of expanded clay concrete.

According to their properties, depending on the application, M300 products are divided into several subtypes.

• Coarse grain has incredible strength and long service life. With its help you can fill the foundations of high-rise buildings.
• Medium-grain is used for screeds, self-leveling floors, work with borders and garden paths. It is used wherever a medium-grained fraction of the mixture is required.
• Fine-grained is also reliable and durable; it is used for plastering work.

When choosing a universal dry composition, you should remember: the more famous the brand and the higher the grade of the product, the more expensive the product and the more reliable its technical properties.

For information on what dry building mixtures are, see the following video.

Consumption of cement-sand mixtures

Table 4. Composition of mixtures and consumption of components

Mixtures are consumed depending on the type of work and the thickness of the applied layer. To accurately calculate the materials used, you can make a test sample and build on its indicators.

For filling the screed

To calculate the amount of material for the screed, you need to find the cubic capacity of the solution used for the fill. To do this, it is necessary to multiply the floor area of ​​the room by the thickness of the layer, the value of which for a screed rarely exceeds 30 cm. For example, in the case of pouring a screed 10 cm thick in a room with a floor area of ​​100 m2, you will need 10 cubic meters of solution, the preparation of which requires from 555 to 713 kg of dry mixture (depending on its brand).

Important!

The higher the grade of the mixture, the higher its density. To prepare a cube of solution from the M100 mixture, you will need 550-600 kg or 700 kg of the mixture TsEM I 32.5N GOST 31108-2016 (grade M400).

Semi-dry mixture for screeds

Semi-dry mixtures can be used to make screeds. Hard (semi-dry) mixtures have a low water content. These mixtures, in addition to cement, sand and water, include fiber fibre, plasticizer and, if necessary, anti-freeze additives. The semi-dry mixture is supplied through hoses using a special device with a pump. Beacons are made from the semi-dry mixture and poured.

Advantages of the semi-dry mixture:

• performing the screed in one step;
• fast hardening;
• reduction of shrinkage and cracking.

Semi-dry screed is a high-tech process that improves the quality of work.

Wet screed

It is made from cement-sand mixtures of grades M150-300. The dry mixture is mixed with water on the spot. The surfaces to be poured are pre-primed. The primer forms a thin film with increased adhesive properties. The primer film retains moisture in the screed.

Thermal conductivity coefficient of cement-sand screed

The thermal conductivity of the floor screed depends on the percentage of cement and sand. An ordinary cement-sand mortar has a thermal conductivity coefficient of 1.2 W/m*K, which means high thermal conductivity of the material and significant heat loss, that is, the floor will be cold, and more money will be spent on heating.

Important!

The thermal conductivity coefficient of the screed during engineering calculations is selected from reference tables, which show indicators depending on the material used. The thermal conductivity coefficient of building and thermal insulation materials is 0.02-2.1 W/m*K and depends on temperature (increases with increasing temperature). As the density of the material increases, it grows, but the presence of cavities, pores and air layers does not allow the material to be considered homogeneous. Since the thermal conductivity of gases is in the range of 0.004 to 0.4 W/m*K, the overall density decreases; in this case, heat transfer decreases and the thermal conductivity of the screed decreases.

Expanded clay or expanded perlite can be used as a thermal insulating filler that reduces the thermal conductivity of the floor screed; however, the more filler, the less durable the screed will be. In addition, large filler makes it difficult to create a flat floor surface.

For plastering walls

Material consumption can only be determined approximately, because walls can be uneven, with protrusions, depressions, and gaps.

Therefore, the average layer depth is determined for calculations.

Important!

The thickness of the plaster layer is 5-30 mm. Lime is often added to the plaster mortar, which reduces the consumption of CPS.

With a layer thickness of 10 mm, the consumption of the M400 mixture per 1 m2 is 1.6 kg, M500 - 1.4 kg.

For bricklaying

For masonry work, a mixture of M100 or M200 is used. Laying 1 m3 of wall requires 250 g of dry fiber cement.

Important!

It is necessary to clarify the data according to the regulatory documentation.

How to save CPS

To reduce the consumption of CPS, fillers are used:

1. expanded clay to reduce thermal conductivity when pouring screeds;
2. lime mortar for plaster.

In addition, you can use high-quality cement, reducing its amount in the mixture, or backfill foundations to reduce solution consumption.

Specifications

The technical characteristics of sand concrete determine the rules of its operation and resistance to external destructive factors. The composition and technical properties of the M300 mixture make it possible to use it both as a self-leveling compound (self-leveling mixture) and as a repair composition.

Compound

Any variants of M300 mixtures are gray in color. Its shades may vary depending on the composition. For such materials, Portland cement M500 is used. In addition, the M300 mixture, according to GOST, has the following proportions of the main components: one third of cement, which is the binding ingredient, and two thirds of sand, which is the filler.

Frost resistance

This indicator indicates the ability of the material to withstand multiple temperature changes, alternating thawing and freezing without severe destruction and reduction in strength. Frost resistance allows the use of M300 sand concrete in unheated places (for example, in permanent garages).

Frost resistance of mixtures with special additives can be up to 400 cycles. Frost-resistant repair mixtures (MRMs) are used for mixing construction compounds used in the reconstruction and restoration of concrete, reinforced concrete, stone and other joints, filling voids, cracks, anchors and for other purposes.

Compressive strength

This indicator helps to understand what tensile strength a material has under static or dynamic influence on it. Exceeding this indicator has a detrimental effect on the material and leads to its deformation.

Dry mixture M300 can withstand compressive strength up to 30 MPa. In other words, given that 1 MPa is approximately 10 kg/cm2, the compressive strength of M300 is equal to 300 kg/cm2.

Temperature range

If the thermal conditions are observed at the time of work, the process technology is not disrupted. The continued preservation of all the performance qualities of concrete is also guaranteed.

It is recommended to carry out work with M300 sand concrete at temperatures from +5 to +25? C. However, sometimes builders are forced to violate these recommendations.

Adhesion

This indicator characterizes the ability of layers and materials to interact with each other. Sand concrete M300 is capable of forming reliable adhesion to the base layer, which is equal to 4 kg/cm2. This is a very good value for dry construction mixtures. To ensure maximum adhesive performance, manufacturers provide appropriate recommendations regarding preliminary preparation work.

Bulk density

This indicator means the density of the material in its uncompacted form, taking into account not only the volume of particles, but also the space that has arisen between them. This value is often used to calculate other parameters. In bags, the M300 dry mixture is in bulk with a density of 1500 kg/m3.

If we take this value into account, it is possible to draw up an optimal ratio for construction. For example, with the declared density, 1 ton of material is 0.67 m3 in volume

In small-scale construction work, a 10-liter bucket with a volume of 0.01 m3 and containing about 15 kg of dry mixture is used as a measure of the amount of material.

Sand particle size

Factories produce M300 sand concrete using sand of different fractions. These differences determine the peculiarities of the technique for working with the solution.

There are three main sizes of sand used as raw material for dry mixtures.

• Small size (up to 2.0 mm) – suitable for street plastering work, leveling seams.
• Medium size (from 0 to 2.2 mm) – used for screeds, tiles and borders.
• Large size (more than 2.2 mm) – used for pouring foundations and foundations.

Mixture consumption

This indicator characterizes the material consumption with a layer thickness of 10 mm per 1 m2. For M300 sand concrete it is usually in the range from 17 to 30 kg per m2. It is worth noting that the lower the consumption, the more economical the work costs will be. In addition, manufacturers often indicate the consumption of sand concrete in m3. In this case, its value will vary from 1.5 to 1.7 t/m3.

Delamination

This indicator characterizes the connection between the lower and upper parts of the solution. The M300 mixture usually has a delamination rate of no more than 5%. This value fully complies with the requirements of the standards.

Types of cement-sand mixtures

Dry CSPs are classified according to the following criteria:

1. by percentage of cement;
2. by the number of binding components;
3. by the density of the frozen solution;
4. by strength;
5. by appointment;
6. by cost.

Let's look at each classification.

Fat and skinny

Based on the percentage of cement, mixtures are divided into three types:

1. fatty,
2. normal,
3. skinny.

The higher the cement content in the mixture, the faster the solution hardens.

Fat mixtures

The sand to cement ratio is lower than 3:1. The disadvantage of a fatty mixture is that the finished concrete is prone to cracking. To prevent it, high-grade cement is used to produce fatty mixtures.

Normal mixtures

For 3-5 parts sand, 1 part cement.

Skinny Blends

The ratio of sand and cement is higher than 5:1. Mixtures with a lean composition harden slowly and tend to crumble over time. High grade cement helps avoid this.

Binding components

As part of a cement-sand mixture, cement acts as a binder, that is, the component that reacts with water with the subsequent formation of a solid material (concrete stone).

In addition to cement, the mixture may contain other binding components:

1. gypsum,
2. lime,
3. magnesium compounds.

Interesting!

Cement is a water-hardening binder, and gypsum, lime and magnesium compounds are air-hardening.

Mixture options containing only cement as a binder are called simple; mixtures with the addition of air-hardening binders are called complex.

Cement-based plaster mixtures have the following advantages:

1. suitable for external and internal finishing and restoration work;
2. provide a durable and long-lasting coating;
3. good adhesion to smooth surfaces (foam blocks, aerated concrete, smooth stone, previously plastered surfaces);
4. low consumption on porous surfaces;
5. the cost is 1.5-2 times lower than that of gypsum;
6. moisture resistance, which allows it to be used for exterior work in the house and for finishing kitchens and bathrooms.

Disadvantages of cement plasters:

1. complex application in several layers or stages;
2. long drying of the coating;
3. porous surface;
4. low decorative properties of the coating.

Advantages of mixtures with the addition of gypsum:

1. plastic;
2. no shrinkage;
3. quick drying;
4. light weight;
5. vapor permeability;
6. environmental friendliness;
7. good sound and heat insulation properties of the coating;
8. white color and susceptibility to decorative finishing, including volumetric ones.

Disadvantages of plaster with the addition of gypsum:

1. low moisture resistance and unsuitability for outdoor use;
2. high price;
3. lower strength than cement plaster.

Light and heavy

Based on the density of the frozen solution, they are distinguished:

1. heavy mixtures (over 1500 kg/m3);
2. light mixtures (up to 1500 kg/m3).

Marking of mixtures by strength, technological characteristics of DSP and the use of different types of mixtures

Table 1. Cement grades and mixing proportions to obtain the mixture of the desired grade

Depending on the compressive strength, mixtures are marked with the letter “M” with a numerical designation:

1. M10-M25 – mixtures with clay.
2. M50-M100 - mixtures with the addition of lime, due to which the cement content is reduced. Used for plastering and repair work, leveling and eliminating minor defects such as cracks, potholes, and crevices.
3. M150 - universal mixtures. They are used for masonry and plastering work, preparing mortars for screeds and repair work. The recommended layer thickness is 5-50 mm, consumption is about 16.5 kg/m2 with a layer thickness of 10 mm. Setting time is 2 hours, hardening time is 24 hours.
4. M200 – assembly and masonry mixtures. They are produced in various modifications for different types of work (preparing plaster or masonry mortar for bricks, pouring screeds). Consumption for a thickness of 1 cm is about 15-17 kg/m2.
5. M300 and mixtures for especially strong concrete. They are called sand concrete. More expensive than M150 mixtures, sand concrete has a narrower scope of application. They are used in cases where special strength of products is required (masonry mortars for the installation of block structures, slabs, massive screeds). Not suitable for plastering work.

Table 2. Brands and properties of mixtures

Important!

In accordance with GOST requirements, the number next to the letter “M” shows what compressive load the hardened mortar prepared from this mixture can withstand.

Mixtures for various purposes

Table 3. Composition and purpose of mixtures

Depending on the purpose, mixtures are divided into the following types:

1. Mixtures for screeds. They are made on the basis of cement TsEM I 32.5N GOST 31108-2016 (grade M400), and sand in a ratio of 1:2 or TsEM I 42.5N GOST 31108-2016 (grade M500), with sand 1:3. To reduce the risk of cracks in the screed, synthetic fiber fiber is added (0.7-0.9 kg per cubic meter of mixture).
2. Mixtures for bricklaying. The ratio of cement and sand is from 1:3 to 1:5.
3. Mixes for plaster. They are made on the basis of M200 or M300 cement. The proportion is 1 part cement to 3 parts sand.

Important!

Cement-sand mixtures, like cement, lose their properties during long-term storage. After a year, the strength is reduced by half. In open packaging, the loss of material properties occurs faster.

Dear and... not very

Cement-sand mixtures are classified into three groups based on price:

1. "Pants". More expensive than building materials purchased separately, 2-2.5 times. The mixtures contain special cement.
2. Cement-based mixtures with rheological additives that increase the adhesion and water-retaining characteristics of the mixture. Used when mixing solutions for plastering and laying tiles.
3. Mixtures with surface additives that are resistant to abrasion. The most expensive.

Cement-sand mixtures may contain additives that give them special properties:

1. Plasticizers. They impart plasticity and mobility to the solution, which reduces the consumption of cement and water, improves the workability of the mixture, eliminates air bubbles, increasing the density of the concrete stone, reduces shrinkage and reduces the risk of cracks. Used for pouring foundations, screeds, and heated floors.
2. Hardening speed regulators. Allows you to speed up or slow down the hardening of the material.
3. Additives that impart hydrophobicity to concrete and mortar.
4. Additives for frost resistance. They are of great importance for carrying out concrete work at temperatures below 0 degrees. Celsius.
5. Additives that provide the ability of concrete to retain water, reducing the amount of unbound water. They are used when working on moisture-absorbing substrates (sand-lime brick, foam concrete).

What is sand concrete made of?

The characteristics of sand concrete m300 (composition, proportions 1 m³) are standardized by GOST 7473-94.

High-quality dry mixture contains:

• Portland cement PC500 D20/PTs400 D0;
• fractionated dry sand, with a combined composition of fractions (particle size 0.80-4.0 mm);
• other additives (frost-resistant, microsilica, fiberglass) are introduced at the discretion of the manufacturer.

Sand concrete M300 can be used to construct wear-resistant, high-strength floors as a load-bearing covering in utility and residential premises, including garages, basements (with a load of 250-300 kg/cm²)

Depending on the sand used, M300 grade material is used to carry out certain work:

Composition of sand concrete m200

The composition of sand concrete is determined by GOST 31357 - 2007 “Dry mixtures for construction with a cement binder”. Each manufacturer can make small additions to the composition of the mixture, but there are key components and indicators that are standard.

Main components:

• Cement m400;
• Sand;
• Crushed stone;
• Water.

When creating, Portland cement M400 is mainly used; it is one of the most common, and its technical characteristics meet all specified standards. Sand is used in two types of fractions - fine-grained and coarse-grained, thoroughly cleaned of foreign impurities.

The composition and proportions of sand concrete m200 per 1m3 according to construction standards, the mixture consumption is:

• Portland cement - 265 (1 part);
• sand 860 (2 parts);
• crushed stone 1050 (5 parts);
• water 180 (? parts).

Tips and tricks

When planning to prepare a cement-sand mixture, you must immediately decide in what proportion the different components will be taken, what grade of strength is needed, and what the main properties are.

It all depends on the scope of application of the mortar - so, if M50 or M75 is suitable for brickwork, then for screed prepare at least a mixture of M150, 200 and higher. The composition of any CPS includes cement, sand, water, but the result is different depending on the ratio.

Some tips from the experts:

• To prepare a plastic mixture, you can add liquid soap to the solution, previously thoroughly mixed with water.
• You need to know how to properly dilute cement and other components: first, all the dry substances are mixed, then water is added in small portions so that you can control the thickness of the mixture and achieve the ideal consistency.
• When preparing, take into account the brand of building material from which the walls are built. It is desirable that the parameters coincide - then the wall will have a homogeneous structure, reliable and durable.

• Before you make your own cement for plaster, you should take care of purchasing perlite. If you replace some of the sand with it, you will be able to achieve higher thermal insulation characteristics.
• For work, we use exclusively fresh cement, without lumps, produced according to technology and stored in optimal conditions - in this case, it will be possible to achieve the most uniform mixing and high adhesion.
• Detergent or soap is also added to the cement (the proportions remain the same, it is simply mixed with mixing water) to increase adhesion.
• The solution is best prepared in a container made of metal, plastic or wood.
• To thoroughly clean the sand from impurities that can reduce its strength, you can soak it in water for a short time.
• The consistency of the finished cement-sand mixture is usually checked with a trowel: the solution should be distributed evenly over the tool, but not run off (it is worth remembering that this rule works in the preparation of standard mixtures; for some tasks other properties may be important).

• The finished DSP is used for an hour after mixing, until the solution begins to thicken and harden. Therefore, you need to immediately prepare the required volume - exactly as much as you can produce in an hour.
• It is forbidden to dilute an already hardened solution with water, as it immediately loses its properties and can cause destruction of the structure/building.
• When mixing a mixture in a volume greater than 2 cubic meters, no drills or attachments will help - only a concrete mixer or ordering the required volume at the factory.
• The solution, which is planned to be used where minimal loads and low mass are noted, can be prepared with a reduced volume of sand. But this approach is only possible on the condition that before properly mixing the DSP, the master has precisely determined the specifics of the application and the remaining solution will not be used for the implementation of any other tasks.
• Mixing the cement-sand mass should last at least 20 minutes - this way the solution will be homogeneous and of high quality.
• The ratio of the proportions of the components is looked at in GOSTs and SNiPs (the opinion of experienced craftsmen is allowed), as well as in the recommendations of the manufacturer of cement, dry mix, etc.

Cement-sand mixture is a universal material that can be used to perform a whole range of works, obtaining the most durable and strong structures. Provided you select high-quality materials and follow the technology for preparing the mixture for the task at hand, everything can be accomplished quickly and easily.

Calculation for materials

Sand concrete M300 is mixed with cold water at temperatures up to +20 degrees without any impurities in the composition. Water consumption is determined by the proportion: 10 kilograms of dry mixture requires 1.7 liters of water. Mix the solution with an electric drill with a special attachment.

If you plan to prepare large volumes, use a concrete mixer. To improve the quality of mixing, first pour two-thirds of the volume of water required for the composition into the drum, then add it as the concrete mixer works. The solution should be viscous, homogeneous, and plastic. Before starting to work with it, it is advisable to soak the concrete for 10 minutes.

Then you can work with the solution: pour out the concrete and level it with a rule or spatula, then remove air bubbles with a vibrator or bayonet.

For plaster

To prepare the mixture, the relevant proportion is 1:3. You will need about 17 kilograms of cement per square meter with an average thickness of the plaster layer.

For masonry

Here special attention is paid to the sand - it must be clean, without impurities or inclusions. Only in this case will it be possible to knead a homogeneous mass that can reliably hold the masonry material together. The proportions used are different: both 1:3 and 1:6. Consumption per square centimeter is 0.05 m3.

For screed

For floor screeding, M150/M200 grade mortar is usually used. Take cement and sand in a ratio of 1:3 or 1:2 (depending on the brand of cement used). Fiber fiber is often added to the solution in volumes of 800 grams per cubic meter. Consumption is 20-21 kilograms per square centimeter.

Cement-sand mixture is one of the most popular repair and construction materials. But a large range of products makes it difficult to choose the optimal composition. Therefore, calculations must be performed carefully and carefully, following the technology and taking into account the scope of use of concrete.

Peculiarities

Dry mix M-300 is a ready-made masonry mixture, the components of which are selected in the required proportions. Before use, the composition is diluted with water in the volume specified by the manufacturer and mixed mechanically until smooth.

The mixture is sand concrete, since it is based on purified fine-grained concrete and Portland cement. The dimensions of the first do not exceed 3 mm; the Portland cement used has a grade strength of M-400 or M-500). To ensure certain characteristics (frost resistance, moisture strength, and so on), plasticizers are introduced.

Various reinforcing fibers may be present in compositions operated at subzero temperatures. To improve adhesion, a special type of clay, coarse sand, or granite chips are sometimes added.

Unlike conventional concrete mortars, M-300 sand concrete is distinguished by its ease of preparation, plasticity (suitable for laying in a thin layer, which is necessary for certain types of masonry), high strength, and economical consumption. The M300 mixture is a masonry mixture, that is, it is used for fixing bricks or masonry stones. In addition, it can be used as a concrete mixture for casting.

The composition is characterized by non-shrinkage, which allows it to be used as a floor screed. And thanks to its increased strength and wear resistance, the mixture is used even when organizing high-strength floors. The thixotropy of the composition allows it to be used also for leveling floors, as well as sealing cracks in concrete surfaces.

The material is suitable for both private housing construction and the construction of industrial and administrative facilities, as well as the installation of basements and garages. It is used when pouring the foundation, including in places where concrete and reinforcing sections meet. The mixture is also used to create paths in private suburban areas. In its properties, the material resembles fine-grained concrete, therefore it is used both outside and indoors.

Features of calculating sand-cement mortar

The proportions of the components are selected so that small fractions of filler fill the space between large ones evenly. In this case, the material consumption and its density are higher than in conventional mixtures. To account for the costs of sand concrete M 300 for performing a certain type of work, the total volume of concrete is first determined.

How to determine the volume of a solution:

• Pouring monolithic walls, reinforced concrete products - calculations are carried out using standard geometric formulas (reinforcement is not taken into account).
• Masonry - technological standards for material consumption.
• Pouring floors and plastering - calculating the total surface area and the expected layer of mortar. As a rule, the average distance from the base to the beacons (markings) is measured in several places over the area.

On the packaging of the mixture, costs are usually indicated based on the consumption of sand concrete per square centimeter, provided that a layer 1 centimeter thick is created. Average values ​​on packaging are usually 18-22 kilograms. To get the flow rate per cubic meter, multiply the resulting value by 100.

How to reduce costs for sand concrete:

• All grades of material are supplied in bags weighing 25-50 kilograms and fully marked. If there is no information on the packaging, as well as an indication of the standard weight, you should not risk buying a low-quality mixture.
• It is more profitable to buy large bags - loading/unloading is cheaper, and the material itself is cheaper in bulk (5-15%).
• On the other hand, you should not buy too much of the mixture, since the shelf life of cement is short and you will simply have to throw away the excess. At any convenient time in Moscow and the regions, you can purchase additional material without stopping production.
• When choosing a supplier, they will find out the cost of delivery - due to the poor location of the warehouse, transportation can increase the price by 25-50%.
• It is undesirable to buy very cheap cement - rarely does a manufacturer agree to supply its product much cheaper than its competitors. Most likely, a low price is an indicator of the same quality.

General information

A characteristic feature of concrete is its composition, as well as proportions and preparation technology. It consists of cement, fine and coarse fillers, water and various additives. In addition, there are brands of concrete that do not contain coarse filler. There are different mixtures that are used for specific cases and also have different properties.

Designation and its interpretation

Concrete structures gain full strength within 6 months, and in 30 days concrete gains 70% strength. M300 is used in all structures that are subject to significant load, therefore, one of the main indicators is its strength. The MXXX designation template does not indicate a specific brand, but is an indicator of the maximum compression pressure.

In addition, there are other designation patterns, for example, FXXX and WXXX, indicating frost resistance and water resistance, respectively. The M300 class of concrete shows the totality of all grades whose ultimate strength is 300 kgf/sq.m. cm. The tensile strength is tested in laboratory conditions by applying force to parallel planes of a product cast from concrete, in the shape of a cube with a side of 150 mm. The grade of concrete in terms of strength is correlated with its class. These indicators should be selected for the construction and calculation of the finished structure at the maximum load that it can withstand.

M300 corresponds to class B22.5 with a coefficient of variation (CV) that is 13.5%. It shows the homogeneity of the mixture from which any brand of concrete is made. When this coefficient changes, the grade of concrete will also change, that is, if its value is low, the grade will increase and vice versa. If the concrete is M300, then with different values ​​of the coefficient its class will change:

1. At Kv = 5% the class is B25.
2. At Kv = 13.5% - B22.5.
3. At Kv = 18% - B15.

Main characteristics

Concrete is classified into grades, and this distribution is primarily related to the parameters of strength (B), density (D), water resistance (W), frost resistance (F) and workability (P). One of the best options for most construction work is M300 concrete, the characteristics of which are as follows:

1. Strength: B22.5 with an indicator of 295 kg/sq. cm.
2. Specific gravity of concrete M300: 1800−2500 kg/cubic. m.
3. Water resistance: W6-W8.
4. Frost resistance: F200-F300.
5. Mobility: P2-P4.

The strength indicator is the main characteristic and shows the maximum effect of forces during compression, at which the structure collapses. The specific gravity or density of M300 concrete depends on the type of coarse filler included in its composition. When using limestone, the D value is about 1800 kg/m3. m., and when using harder rocks (crushed granite, granodirite, etc.) it can reach a value of 2500 kg/cubic. m. Due to its high density, this type is classified as heavy. The density indicator depends on the presence of violations in the manufacturing technology and air cavities.

Water resistance (WXX) is a value indicating the water pressure in MPa to pass through 0.15 m of concrete. For concrete grade M300, this indicator is equal to W5-W6; at a pressure of 0.5-0.6 MPa (approximately corresponding to 5-6 atmospheres) it does not allow water to pass through at all. By adding hydrophobic cement, additives and carefully compacting the solution, it is possible to increase the waterproof rating.

Frost resistance is indicated in the form of the FXXX pattern and shows the number of defrost-freeze cycles without loss of strength. This characteristic can be increased in several ways:

1. The use of additives that prevent the formation of air bubbles.
2. Removing air from the concrete mixture using vibrators, as well as using various compactors.
3. Reducing the amount of water (impairs mobility).
4. Using solid fillers instead of crushed limestone.

Application in construction

Since M300 has good strength, frost resistance, water resistance and mobility, it is widely used in construction. In addition, its main indicators can be adjusted by changing the components included in the concrete mixture. It is advisable to use it for the following work:

1. Construction of platforms, roads and curbs.
2. Installation of walls and various supports.
3. Construction of stairs, landings and pouring of foundations in multi-storey buildings.
4. Production of reinforced concrete products and fences.
5. Production of sewer pipes that are constantly exposed to moisture.
6. Construction of objects that are affected by constant temperature changes.

How to prepare TsPS?

Each ready-made mixture must be accompanied by instructions on the required amount of water; other components are usually not provided. When used as part of additional materials (dyes, reinforcing fibers), the proportions must be observed strictly in accordance with the instructions for the additive. The typical ratio of mixture to water is 5 to 1 (a bucket of water per 50 kg bag of mixture), the share of dyes is 0.1%, the share of fiber fiber is 1%.

When making it yourself, the proportions of water and sand to cement are taken depending on the type of work being carried out, strength requirements, and the degree of moisture content of the sand:

1. The thickest mortar required for masonry is the water/cement ratio of no more than 0.8.

2. For screed and plaster, sour cream-like compositions with a W/C ratio of 0.8–1.2 are used.

3. When spraying and grouting, dilute the solution even more, up to W/C - 1.5.

4. Mixtures with W/C less than 0.6 are used when it is necessary to obtain a quick-drying high-grade cement-sand mortar (M300 and higher), or for concrete.

If a concrete mixer is used for mixing, it is recommended to carry out the work in the following order:

• Pour water into the untwisted drum and add additives.
• Add 2 buckets of sand.
• Add a bucket of cement and wait for it to mix.
• Add the remaining sand and add water if necessary.

When kneading by hand, water is poured into the dry mixture. If you do the opposite, water forms a film of cement on the surface of small lumps of the mixture, which will slow down the process many times over. If the composition is made from its own components, it is advisable to mix them dry before adding water.

Once prepared, the solution must be used before it begins to harden - from 15 minutes to several hours, depending on the use of additives, cement concentration and temperature. The usual solution M150-M200 at a temperature of 20 ° C begins to harden an hour after mixing.

Consumption

To plan the mass of the CPS in advance, you need to approximately calculate the required volume of solution and multiply it by the cost per 1 m3 indicated in the description of the mixture. Most often they are indicated in the format “mixture consumption per m2”, meaning a layer 1 cm thick. To get the costs per 1 m3, just multiply the indicated value by 100.

The usual consumption values ​​for sand-cement mixture are 1800 kg/m3, for high-quality compositions - up to 2200 kg/m3, for lightweight plasters with lime - 1200-1600 kg/m3.

Calculating the volume of consumption of mortar for plastering work and screed is not particularly difficult, but the cost of material for masonry depends on the skill of the particular performer. If you strictly follow the technology, the solution consumption will be 25% of the total volume of the wall, but in practice this value can be either up to 35% (thick seams, losses due to splashes) or below 20% (waste masonry, use of poor-quality techniques to speed up work ).

Types of materials

Sand-cement mixture M300 is used in a wide variety of repair and construction areas. The material is divided into types according to its purpose. Thus, sand concrete is most often used to create a wear-resistant, high-strength floor screed with the possibility of not having to perform additional coating.

The solution is often used to restore partially cracked or crumbled structures, create concrete products, and various types of paving slabs. TsPS 300 is ideal for plastering/masonry mortar - in this case, the mixture is prepared from a filler fraction of less than 2 (for plastering) and 4 (for masonry) millimeters.

Sand concrete M300 is used for the production of expanded clay concrete grade M200 by adding crushed stone or expanded clay to the mixture in a 1:1 proportion to the volume of dry material. Precise instructions regarding the ratio of dry mixture and water, optimal working time and setting, as a rule, are indicated on the container with sand concrete.

On average, they take 1.5-2 liters of water per 10 kilograms, work with the solution for 1-2 hours, and it sets in a day or two, gaining full strength within a month. If you overdo it with water, concrete can shrink greatly, cracks often appear, and technical characteristics deteriorate.

The exact proportions and types of mortar are prepared for each case individually, taking into account the specific properties and parameters, as well as the scope of application of concrete.

Peculiarities

Cement mortars with sand are used to perform a wide variety of work during the construction, finishing, and renovation of buildings. It’s not difficult to make a mixture with your own hands, but you need to know the exact proportions of cement, sand and water. The easiest way to mix is ​​to use a concrete mixer, renting or purchasing one.

Before making a solution of cement and sand, it is necessary to decide on the scope of application, since the proportions differ within significant limits. The most popular is considered to be DSP for brickwork: cement-sand mortar is used to create load-bearing walls, and with the addition of lime for internal walls.

The composition of the cement mortar largely depends on the working conditions and operation. If work is carried out in frosty conditions, then special anti-freeze additives are added to the composition to prevent the CPS from freezing. But they are suitable for working in frosts below -20 degrees (it’s better not to do anything at all, but to wait for warmer weather), since they will not be flexible and flexible enough.

If a cement solution is prepared for use in monolithic hearths with an open fire source, in the construction of a furnace or firebox, then heat-resistant fire-resistant mixtures are created: from cement of at least M400 grade, with crushed brick, fine fireclay sand.

For each type of task and working conditions, a solution is prepared from basic materials, but in different proportions and with the addition of additives and plasticizers. As a rule, additives change one parameter - this could be the rate of hardening, mobility, frost resistance, etc. Each master determines priority tasks and performs calculations before preparing the cement mortar.

Material consumption per 1 m2, 1 m3

A dry mixture of sand and cement is quite in demand on the market today. The thing is that such concrete is easy to prepare, it is relatively inexpensive, and gives good results in the form of brand strength, frost resistance, and other important indicators.

To obtain a solution, you simply need to add water in the indicated volumes. Also on the market you can find dry mixtures with plasticizers that change certain characteristics. During the production process, chemical impurities are added to the powder, improving qualities such as water resistance, adhesion, resistance to frost, wear, mobility, ductility, strength, etc.

Any sand-cement mixture assumes a specific purpose, based on which components and proportions are selected. The main importance is strength; the type of solution being mixed and the proportions of the components in the composition depend on it. So, for the M100 brand, cement and sand are taken in a ratio of 1:3.

To calculate how much sand concrete is needed per 1 m2, 1 m3, you first need to determine the average consumption of the sand-cement mixture - this figure is 1.7-1.9 kilograms per millimeter of layer. The main thing here is thickness. If the layer thickness is 2 millimeters, the material consumption will be 3.6 kilograms; for a thickness of 5 millimeters you will have to spend 9 kilograms per square centimeter.

If we take practical values, then usually pouring a floor with a layer thickness of 1 centimeter requires 21-22 kilograms of material per cm2. That is, for 20 square meters of floor 1 centimeter thick, 400 kilograms of M300 sand concrete are needed. In accordance with the number of centimeters of layer thickness, this indicator is multiplied by the required value.

Regardless of the task for which the mixture is needed, to obtain a cubic meter of material, you need to use a cubic meter of sand. The proportion looks like this: 1:3, in accordance with it the required volume of cement is found. So, to obtain a cubic meter of M300 sand concrete solution, you need to take 465 kilograms of sand and 490 kilograms of M400 cement or 410 kilograms of M500 cement.