The current state of the accelerated concrete prism test

Expansions due to alkali–silica reaction (ASR) in the accelerated concrete prism test (ACPT–60 °C) show a significant reduction at 13 weeks compared to 52 week testing in the standard concrete prism test (CPT–38 °C). Previous work indicated that increased leaching, higher mass loss and a reduction in the pH were observed when temperature was increased from 38 to 60 °C. After further investigation the authors have revealed that non-reactive fine aggregate from certain sources combined with the same reactive coarse aggregate exhibited further reduction in expansion in the ACPT. Expansion data for a wide range of reactive coarse aggregates in 38 and 60 °C testing regimes is shown. Data investigating the Spratt reactive coarse aggregate combined with seven different non-reactive sands will be shown to demonstrate the dramatic effect of the non-reactive sand. Selected pore solution analyses will be given to further elucidate this issue.