The effect of a complex additive on the structure formation of cement stone in conditions of dry hot climate and saline soils

Abstract

In DHC and saline soils and groundwater conditions, the cement mix quickly loses its mobility and workability. In this regard, it is necessary to plasticize it by introducing various surfactants. However, the surfactant additive used should not slow down the process of hydration and hardening. To ensure salt resistance, it is necessary to increase the density and the strength of concrete. The proposed complex additive was obtained by joint grinding in a ball mill of a soda-sulfate alloy (SSA) and gossypol resin (GR) to a specific surface area of 2800 cm2/g at the rate of 05, -1.5%, and 0.1-0.3%, respectively, of the cement mass. The complex additive was introduced into the mixing water of the cement mix. From the research results obtained, it is seen that with an increase in the content of GR from 0.1 to 0.3%, the normal density decreases by 1.4-4 points, and the setting time (due to the accelerating action of the SSA) decreases at the beginning by 20-50 minutes, and at the end by 60-240 minutes. In 28 days, the control cement gained the strength of 56 MPa, and with a complex addition - 60-68 MPa. The introduction of a complex additive led to an increase in the salt resistance coefficient in the reference cement up to 0.55-0.65, and in the cement with a complex additive up to 0.80-0.86; an increase was observed due to the strength and density of the samples. By increasing the strength, it is possible to save 17-21% of cement.