Combination of LCA and circularity index for assessment of environmental impact of recycled aggregate concrete

Abstract

Multidisciplinary approach is used to evaluate concrete with recycled concrete aggregates (RCA) from technical, environmental impacts and product circularity perspectives. Two RCA replacements investigated, RAC50: fine aggregates; RAC100: both coarse, fine aggregates. Reference, recycled concretes have same cement content, similar workability and compressive strength requirement, proven experimentally. RCA is sourced from pre-fab element discards of a Swedish plant, the logistical alternatives requiring environmental impact analysis. Alternatives are RCA crushing at plant and crushing at a different location including transportation. LCA shows transportation is second largest contributor after cement in all impact categories. RAC alternatives show lower total impact than reference concrete due to RCA replacement. A circularity index for concrete based on economic value of recirculated aggregates; supplements LCA for sustainability reporting. Circularity index results: RAC100 > RAC50 > RC. Combining circularity index with LCA helps optimize recycling process with regard to amount of recycled material and logistics respectively.