Combination Effect of Limestone Filler and Slag on Delayed Ettringite Formation in Heat-Cured Mortar

Abstract

The present paper analyzes the combination effect of slag and limestone filler on the expansion caused by delayed ettringite formation (DEF). Tests were carried out on heat-cured ternary cement mortars with various replacement levels of cement by both limestone filler and slag (15%, 25%, and 45%). The expansion of heat-cured cement mortars was evaluated and verified by measuring their length change, dynamic elastic modulus, and compressive strength over more than 750 days. The addition of limestone filler and slag to portland cement was found to be beneficial to reducing the expansion caused by DEF. It was found that the use of 10% and 20% slag ternary cements with 5% limestone filler delayed the beginning of the expansion and caused a decrease in the long-term expansion. Meanwhile, the use of 40% slag with 5% limestone filler suppressed the expansion caused by DEF.