Assessing the sustainability potential of circular geopolymer concrete: A life cycle assessment and multi-criteria decision making approach

In the life cycle assessment (LCA) of concrete, it is essential to consider the service life, mechanical properties, and end-of-life scenarios to obtain accurate results, especially in the case of comparing geopolymer concretes with ordinary concrete. In this study, a conceptual framework was designed to produce circular concretes based on the main principals of circular economy. Then, a comparative economic and environmental life cycle assessment (LCA) was performed to evaluate the sustainability potential of circular geopolymer concrete (CGPC), geopolymer concrete (GPC), and circular ordinary concrete (COC), as alternatives to Portland cement concrete (PCC), using analytical hierarchy process (AHP). The results showed that using GPC and CGPC significantly alleviated the environmental impacts of cement production, such that they reduced the global warming potential (GWP) by about 69%. The environmental burdens of CGPC were slightly higher than GPC in all midpoint (<5%) and endpoint (<2%) levels. The minimum life cycle cost was related to PCC, and then GPC, CGPC, and COC had higher life cycle costs than PCC with relative total cost of 1.08, 1.14, and 1.18, respectively. According to the multi-criteria decision making and final scores from AHP model, GPC and CGPC performed the best in the sustainability assessment, respectively, with a marginal difference, whereas COC performed the worst. • LCA and LCCA were performed on CGPC, GPC, PCC, and COC. • Resources and IR were the critical environmental indicators for CGPC and GPC. • GPC, CGPC, and COC had higher cost impacts than PCC. • AAS and cement had the main environmental impacts in the studied cases. • GPC and CGPC had the highest sustainability potential while COC performed the worst.