The effect of added high-iron slag on the frost resistance of cement compositions

Abstract

Currently, it is of particular importance to study the possibility of increasing the durability of composite building materials by regulating the chemical and mineralogical composition. In this aspect, it is rational to consider the issues of increasing the frost resistance of cement concrete. It is known that to improve this property in concrete, it is necessary to create the correct structure of the hardened cement stone. The work aims to study the process of clogging the pores of a cement stone due to the formation of finely dispersed phases - ferrihydrite - in the process of hydration of composite Portland cement with the addition of high-iron slag of the established chemical composition. The paper analyzes the chemical and phase composition of concretes obtained based on of slag-containing binders with high values of frost resistance. It is shown that, based on this slag, concrete with frost resistance of 500 cycles has been obtained. Analysis of the hydration products showed that finely dispersed ferrihydrite of ferric iron are formed in the cement stone, which increases the density of concrete, plugging the defects in the microstructure of the C-S-H gel.