CHANGING THE STRENGTH OF CEMENT STONE BY THE INTRODUCTION OF ADDITIVES AND GROUND DOLOMIT

Abstract

One of the effective ways to protect concrete structures from the effects of environmental factors is bulk hydrophobization. The most widespread and more studied are organosilicon substances, the disadvantage of which is a decrease in the initial strength of concrete. The paper presents the results of studies that confirm that the strength of cement stone with an admixture of GKZh-11K is carried out with the participation of the processes of activation of mineral dissolution and dispersion of the surface of cement particles due to the additional formation of H+ protons as a result of the dissociation of KOH. Potassium in bulk hydrophobization acts as an active alkaline center. Thus, the process of dissolving minerals of the dispersion of the surface of cement grains with hydrolysis and hydration can be attributed to pseudocatalysis because the main catalyst for the dissolution of the proton H+ does not regenerate. According to the results of the research, it was found that adding dolomite dispersions and GKZh-11K admixture to the cement dough in an amount of more than 0.2% of the cement mass activates the dissolution processes, which leads to an increase in the number of calcium hydrosilicate nanoparticles, the number of contacts per unit volume of cement stone, a decrease in pore size, and the formation of their closed nature, a decrease in shrinkage phenomena, and an increase in strength.