Investigation of structure formation processes at the hydration of modified gypsum binders and mortars

Abstract

The results of investigations of structure formation processes of a mortar while hardening have been presented in the article. The results obtained indicate that during the period of structure formation and the heat release of solidifying composite gypsum binders and solutions, the heat release in hardening of composite gypsum binders (CGB) and modified gypsum mortars (MGM) proceeds at different rates, and is characterized, in some cases, by the rapid release of hydration heat. As studies have shown, modified gypsum binders and mortars, in order to avoid the appearance of structure defects, should contain setting-time additives, promoting to a decrease in the intensity of heat release and, as consequence, reducing risks of destructive processes. With a large amount of a setting-time retarder, hydration process may be disturbed, and that can be accompanied by following abnormalities (abundant bleeding, slow gain in strength, etc.). Significant heat release during hardening allows using the developed mortars even at negative temperatures, as also evidenced by the results of other researchers.