Effectiveness of 3 different supplementary cementitious materials in mitigating alkali silica reaction

Abstract

Abstract A detrimental chemical reaction between alkali from cement and reactive silica from aggregates can occur in concrete that affects concrete durability and such a reaction is called “Alkali Silica Reaction” (ASR). Many different supplementary cementitious materials (SCMs) have been utilized to mitigate ASR in concrete with varying degree of effectiveness. This investigation studied the effectiveness of 3 SCMs, clay brick powder, glass powder, and natural zeolite, in mitigating alkali silica reaction. Accelerated mortar bar test method (AMBT) according to ASTM C 1260 was employed to study the effectiveness of SCMs in reducing ASR expansion in mortar bars that consisted of a local reactive volcanic aggregate. Cement replacement level of 20 percent by weight was chosen to study the effectiveness of each SCM. It was found that all three SCMs were able to reduce expansion of the mortar bars to under acceptable limit. Natural zeolite was found to be the most effective, followed by brick powder and glass powder. It was postulated that the effectiveness generally increased with the increasing amount of Si in mortar, as well as a decrease in Ca to Al ratio.