The results of studies of the effect of mineral additives of natural and man-made origin on some properties of fine-aggregate concrete with the introduction of a mineral additive from 10 to 25% of the cement weight instead of either a part of cement with an increase in the value of W/ C, or a part of sand with a constant value of the value of W / C are presented. A slight, up to 3%, change in the average density of concrete was revealed. A decrease in the E-modulus from 4 to 14% was recorded when replacing a part of cement, while an increase in the flexural strength, depending on the dosage, was up to 26% (marshallite) and 6% (chemical water treatment sludge), and a decrease in the compressive strength was from 10 to 22%. When replacing part of the sand, an increase of up to 10% of the E-modulus, the flexural strength from 19 to 38% (marshallite) and up to 11% (chemical water treatment sludge) was recorded. The increase in the compressive strength, depending on the type and dosage of the additive, ranged from 8 to 20%. No significant effect of additives on the porosity of cement stone was revealed.

Keywords: mineral additive, fine-aggregate concrete, flexural strength, E-modulus, shrinkage, water absorption

A method of selecting admixtures for the production of dry building mixes is proposed based on the results of an expert assessment of the complex indicator of the workability of application (connectivity, continuity when pulling with a toothed trowel, elasticity, quality of rollers) on a 100-point scale and the strength of adhesion to the concrete base, followed by the calculation of the specific cost of admixtures in the mixture per ton of products, respectively, by one point of workability of application and 1 MPa of adhesion strength, developed as a result of studies of adhesive mixtures made using 4 different cements, 5 water-retaining additives and 12 redispersible polymer powders. The possibility of obtaining adhesive compositions of adhesion class C 2 using redispersible polymer powders of domestic production is shown.

Keywords: dry building mix, adhesion strength to the base, unit cost, processability of application

The article briefly describes the history пояявления hydrophobic cements. Considered one of the прспективных directions for the use of water-repellent additives today - in the dry construction mixtures and confirmed the significance of this direction. The article describes the results of experiments on the impact on the indicators of a cement-sandy solution additives series GMI and the analysis of the received data  

Keywords: hydrophobic cement, hydrophobic additives, dry construction mixtures, porosity of a cement stone, strength cement-sandy solution, involving air, antifoam, antifoam agent

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