Mitigation of Alkali–Silica Reaction in Limestone Calcined Clay Cement-Based Mortar

Abstract

This work aims to assess the potential of limestone calcined clay cement (LC3) in mitigating alkali–silica reaction (ASR). Two General Purpose (GP) cement substitution rates using calcined clay and limestone were tested: 20 and 30% with a ratio 2:1 by mass of calcined clay and limestone. Silica ions dissolution of rhyodacite rock used as reactive aggregate, expansion of mortar specimens using the accelerated mortar bar test (AMBT) and the initial chemical composition of the mortars pore solution were investigated. The combination of calcined clay and limestone significantly reduced the expansion of mortar bars compared to reference mortar using 100% GP cement. The reduction in mortar bar expansion correlates well with the reduction in alkalis ions concentration and pH of the pore solution of LC3 mortars compared to reference mortar. 30% OPC substituted by calcined clay and limestone seems to be able to mitigate the risk of ASR in concrete using alkali-reactive aggregate.