Impact of aggregate mineralogy and exposure solution on alkali-silica reaction product composition and structure within accelerated test conditions

Abstract

Electron microscopy, chemical X-ray microanalysis, and Raman microscopy was used with expansion measurements of mortar bars in a systematic fashion to determine the impact of aggregate composition and exposure variations on alkali-silica reaction (ASR) products’ chemistry and structure. The results show that aggregate mineralogy plays a large role in the composition and structure of ASR products as does the local environment in which ASR products form. Additionally, solution exposure composition, a factor relevant to relating laboratory measurements to field performance, has a significant impact on ASR product chemistry but limited impact on structure, or at least on coordination of SiO2 in ASR products.