Influence of Thermally Processed Zeolite on Properties of Composite Gypsum Binder

Abstract

One effective way to improve the water resistance of gypsum binder is to add a hydraulic additive consisting of Portland cement and an active mineral additive regulating the formation of highly basic compounds. Various natural and artificial mineral substances are used as additives. It is known the effectiveness of fine-ground natural zeolites of the "Honguruu" (hongurin) deposit in the process of composite gypsum binders (CGB). There are also separate studies proving the increase in the activity of zeolites during their calcination at temperatures of 300-400 ° C. This paper presents the results of the study of the effect of the calcination temperature of hongurin on the properties of CGB. As a result of the studies, the optimal calcination temperature of hongurin - 180 ° C was determined. At the same time, the activity of hongurin increases, which provides significant growth of mechanical indicators of rock on the basis of CGB: the ultimate strength at compression of samples at the age of 28 days from compositions without plasticizer increased by 90% at addition of plasticizer in the amount of 1% - by 35%, and at 2% - by 57%. But with the use of calcined hongurin there is a slight decrease in the water resistance of the rock: in the optimal composition from 0,96 to 0,87, it is explained by the decrease in the activity of hongurin due to the reduction in the number of active groups, and the resulting new centers have a Lewis character.