Assessment of effects of ASR-induced cracking on direct shear strength of recycled concrete

Recycled concrete aggregates (RCA) have been adopted as one of the most efficient methods to reduce the carbon footprint of the concrete industry. However, the performance of recycled concrete mixtures made of Alkali-silica reaction (ASR)-affected RCA is primarily unknown. In this work, two types of RCA were produced from ASR-affected concrete with distinct levels of deterioration (i.e., slight and severe). Three levels of secondary damage (i.e., expansion levels of 0.05%, 0.12%, and 0.20%) were selected and evaluated through the direct shear test. Results revealed that RCA concrete’s shear strength depends on the severity of the RCA’s past deterioration. Moreover, the performance of the concrete specimens subjected to direct shear are in accordance with the cracks features formed in the microstructure of the recycled concrete as a function of ASR-induced secondary expansion observed through the damage rating index (DRI).