Evaluation of the ASR of waste glass fine aggregate in alkali activated concrete by concrete prism tests

Abstract

This paper examined the alkali–silica reaction (ASR) of waste glass cullet in alkali activated concrete (AAC), using the ASTM C1293 concrete prism test (CPT), in comparison to that in ordinary Portland cement (OPC) concrete. Test results showed that the 1-year expansions of OPC concrete and ground granulated blast furnace slag (GGBFS) based AAC were 0.21% and 0.13%, respectively, which exceeded the 0.04% limit of the ASTM standard. However, both fly ash (FA) based AAC and FA-GGBFS blended AAC showed 1-year expansions below the recommended limit. The AAC with 60% GGBFS and 40% FA showed the lowest 1-year expansion of all the concretes studied. The expansions showed consistency with the physical appearance, porosity and hydroxyl ion (OH–) concentration in the solution extracted from the concrete samples. Moreover, a detailed microstructural investigation revealed severe deterioration of glass aggregates when used in both OPC concrete and alkali activated GGBFS concrete due to the formation of calcium (Ca) rich expansive ASR gel. However, the gels formed at the aggregate paste interface of alkali activated FA and FA-GGBFS concrete were not typical ASR gels, since they contained high Al/Si ratios and low Ca/Si ratios.