A study into the alkali-silica reactivity of recycled concrete aggregates and the role of the extent of damage in the source structures: Evaluation, accelerated testing, and preventive measures

Abstract

This paper covers the expansion of new concrete containing recycled concrete aggregates (RCA) produced from bridge barriers suffering different levels of damage due to alkali-silica reaction (ASR). RCA sourced from high-deterioration concrete produced a higher expansion than natural aggregate or RCA from low-deterioration concrete, although the difference is not high. The expansion of lab-prepared cylinders with RCA was higher than that of cores extracted from the old concrete elements. The standard accelerated mortar bar test and a modified version thereof customized to accommodate RCA's properties, including high absorption, was effective in predicting the expansion of concrete prisms containing natural reactive aggregates or RCAs cast with different cementing blends. Also, the Concrete Micro Bar Test used with suggested expansion limits at 28 and 56 days was found effective in predicting the expansion of concrete prisms at one or two years for samples with and without preventive measures.