Complex Additives for Concrete Based on Substances of Organic and Mineral Nature

Abstract

The production of concretes with a hard hardening rate is not feasible without the use of modifying additives. The development of the chemical industry has led to the emergence of a large number of additives with different properties. Some increase the frost and corrosion resistance, the strength of building materials, while others affect the setting of concrete and the water-cement ratio. Of greatest interest is the joint work of the additives in the composition of the cement stone. The paper analyzes and determines the effect of various combinations of chemical additives (sodium carbonate Na₂CO₃, sodium chloride NaCl and sodium nitrate NaNO₃) on the structure formation and properties of cement stone as part of a complex additive using the simplex-lattice experiment planning method. In the course of the research, to obtain cement stone, Portland cement M500 D0 has been used with the addition of Na₂CO₃, NaCl and NaNO₃ in the established proportions. As a result of tests, it has been found that the following proportions of the components in the composition of the complex additive are optimal: NaNO₃ – 12–38 %; NaCl – 34–54 %; Na₂CO₃ – 26–42 %. With the introduction of this complex into the composition of the concrete mixture, positive dynamics have been observed in neutralizing the corrosion effect on reinforcement in concrete, as well as an accelerated set of concrete hardness. The results obtained can be used at specialized enterprises of the chemical industry, as well as in further research in the development of modifying additives.