Sustainability of alternative concretes – emergy and life cycle analysis

Abstract

Construction industry contributes the highest CO 2 emissions, in which concrete production is one of the key components. Extracting and transporting raw materials like limestone and aggregates contribute to habitat destruction and pollution. This study deals with the relative assessment of a group of commonly used concretes in varied strength levels using emergy analysis and Life Cycle Assessment (LCA). Six types of concrete are considered for evaluation: normal, binary blended, ternary blended, quaternary blended, alkali activated, and recycled aggregate concrete (RAC). Emergy analysis considers different qualities and quantities of inputs, providing insights on the resource-based impacts through emergy indicators. LCA, conducted using SimaPro software, evaluates the environmental impacts of concrete production using midpoint and endpoint indicators. From emergy analysis it is inferred that of concrete with alternative materials like fly ash, silica fume, GGBS, and recycled aggregate exhibited better results in terms of emergy indicators. RAC showed the highest value of emergy sustainability index in all strength ranges. In LCA, impacts were seen higher for normal concrete, followed by RAC. To obtain a more inclusive result, an emergy-LCA integrated index (IELI) is proposed. Results from this index aids in improved decision-making regarding the sustainability of the system considered.