Forecasting Strength of Portland Cement in the Presence of Fuel Ashes

Abstract

Reducing the consumption of the most widespread and expensive in construction inorganic binder of hydration hardening type - Portland cement - is one of the most important tasks for the construction industry. With the current trend of resource- and energy-saving, as well as a decrease in environmental pressure, it is of great interest to use wastes from fuel and energy enterprises in the form of various types of ash (acidic, basic), which are finely dispersed raw materials of mainly aluminosilicate composition that have accumulated in large quantities on our country territories. The paper analyzes the effect of mineral additives in the form of fuel ashes, the use of which provides replacement of part of Portland cement (15-30 % of the total mass of Portland cement, in increments of 5 %), on the kinetics of hardening of the binder. Based on the results of the strength tests of binder samples with additives, calculation of predicted strength was carried out according to the methodology by Sh.M. Rakhimbayev based on transfer theory. As a result, the analysis of the kinetics of the Portland cement hardening was carried out both at early and late hardening periods; efficiency and optimal concentration of fuel ashes depending on type have been established.