Assessment of the effect nitrites and fluorides on the change in the strength of concrete

Abstract

The article describes examples of using inorganic salts and their mixtures for accelerate of hardening cement concretes in practice of modern construction. The results of the research of a complex mixed additive based on inorganic fluorides and nitrites, which accelerate the process of hardening of cement concrete are presented. The composition of the additive allows to accelerate the process of hardening the cement stone, due to the formation of dense and insoluble compounds in the pores of the cement stone. The experimental part included the process of determining the optimal amount of fluorides and nitrites in the additive. The results of the research showed a reduced additive consumption per 1m3 of heavy concrete. The advantages and disadvantages of the additive, which identified at experiments, allow us to recommend its use for accelerating the hardening of concrete in wet neutral and slightly acidic environments. The methods of tests that were carried out using certified and calibrated measuring instruments are described in detail. According to the results of the tests, the dependence of the concrete hardening rate on the amount of additive used was revealed, and the ways of practical use of the additive in the production technology of concrete and reinforced concrete were proposed. Also, according to the results of destructive and non-destructive testing, an increase in the strength of concrete by >15% compared to conventional concrete was found.