Aggregate alkali–silica reactivity and mitigation effectiveness evaluation with miniature concrete prism test

Existing test methods for the evaluation of alkali–silica reaction (ASR) in aggregates such as the concrete prism test (CPT) and the accelerated mortar bar test (AMBT) have shown to be either time consuming or unreliable owing to false positive/negative results. The miniature concrete prism test (MCPT) method, which only requires up to 84 days for testing, could be beneficial for ASR evaluation. To investigate the feasibility of the MCPT method, a comprehensive study was performed to compare the results obtained from MCPT, CPT and AMBT methods. The results showed an agreement of 95.8% between the MCPT and CPT results for the evaluation of ASR. It was found that the 56-day MCPT method usually produced a higher expansion than the 1-year CPT method for most of the reactive aggregates. For coarse aggregates, the MCPT method and the AMBT method produced an agreement of 83.3% for evaluation of ASR. For mixtures with supplementary cementitious materials, an agreement of 79% was observed between the MCPT and CPT results for ASR mitigation effectiveness evaluation.