EFFECT OF MODIFYING CHEMICAL ADDITIVES AND MICROSILICA ON THE STRENGTH GAIN KINETICS OF FHC.

Abstract

The article presents the results of studies of the possibility of accelerating the strength gain period of heavy concrete with the use of modern modifiers. The basic composition of fast-hardening concrete (FHB) of the class of average strength B25 was developed. Further, known methods and approaches were analyzed to accelerate hardening of BTB. Two main modifiers were chosen and a working hypothesis was adopted, which was to apply the method of mathematical planning of experiments in the search for an optimal and effective combination of microsilica and hyperplasticizer of the 2nd generation based on polycarboxylate esters. In the course of experiments by modeling the average strength values of samples in the early periods of hardening the optimum amount of chemical additive for obtaining high-quality bTB was deduced. The test results showed a real possibility of accelerating the hardening of BTB by 50% at the age of 2 days, a positive effect of accelerating the kinetics of strength gain and the possibility of saving the binder (cement) up to 20% when using microsilica.