Prevention of ASR in Recycled Concrete: A Literature Review

Recycled concrete is an alternative source of aggregates to produce eco-friendly concrete. However, some recycled concrete aggregate (RCA) sources may have been contaminated by previous deterioration mechanisms, such as alkali-silica reaction (ASR). Although it has been demonstrated that ASR-affected RCA continues to progress through secondary expansion in new concrete, the prevention approaches for ASR-affected conventional concrete may not be efficient for RCA-concrete. A Scoping Literature Review was conducted to assess the state-of-the-art of ASR prevention in RCA-concrete. Five supplementary cementitious materials (SCMs) and lithium nitrate were the most common materials used to prevent ASR in RCA-concrete, tested using five different methodologies. Since ASR-affected RCA concrete is prone to secondary induced expansion, depicting a need to characterize RCA material regarding deterioration source (i.e., reactive coarse and fine aggregate) and previous level of damage, enabling adjustment of the prevention specifications accordingly.