Influence of compound additive on concrete in hot and dry climate

Tashkent Institute of Architecture and Civil Engineering, Tashkent, Uzbekistan

^* Corresponding author: narov_r@gmail.com

Abstract

In the conditions of hot and dry climate, the concrete mixture quickly loses its mobility and workability. In this regard, it is necessary to plasticize it by introducing various surfactants; at the same time, the surfactant additive should not slow down the process of hydration and hardening. To ensure salt resistance, it is necessary to increase the density and strength of concrete. The proposed complex additive is obtained by joint grinding in a ball mill of soda sulfate melt and gossypol resin to a specific surface of 2800 cm2/g at the rate of 0.5-1.5% and 0.1-0.3% by weight of cement. From the obtained results, it can be seen that with an increase in the content of gossypol resin 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 soda sulfate melt is reduced at the beginning by 20-50 minutes and the end by 60 - 240 min. Reference cement for 28 days gained a strength of 56 MPa, with a complex additive of 60-68 MPa. The coefficient of salt resistance of the reference 0.55-0.65 and with a complex additive of 0.80-0.86 is observed due to the strength and density of the samples. Increasing the strength makes it possible to save 17-21% of cement.