Sustainable recycled geopolymer concrete with rubber, glass, and fibers: mechanical performance and life cycle assessment
摘要
The increasing consumption of cement is among the largest contributors to global carbon dioxide emissions, which calls for sustainable alternatives to conventional Portland Cement Concrete. One promising low-carbon concrete option is geopolymer concrete (GPC), made with industrial by-products like fly ash and ground granulated blast furnace slag. This research focuses on the mechanical and environmental performance of GPC incorporating recycled aggregates and waste additives (rubber crumbs, glass powder, fibers). A cradle-to-gate Life Cycle Assessment (LCA) was conducted on a volume-based (m3) and strength-based (m3.MPa) approaches, as well as Multi-Criteria Decision-Making (MCDM) analysis. Strength in mixes incorporating recycled aggregates ranged from 59 MPa (RGPC with rubber) to 77 MPa (RGPC with fiber), compared to 52 MPa for the control mix. GPC outperformed conventional concrete, with natural aggregate GPC achieving a strength of 83 MPa. The LCA result shows a 65%–70% reduction in global warming potential and a 24%–45% reduction in embodied energy, with ozone depletion and acidification potentials being increased but remaining low in magnitude, hence showing insignificant environmental impact. MCDM ranked RGPC with rubber as the highest under volume-based evaluation, and natural aggregate GPC under strength-based assessment. The m3·MPa functional unit proved to be more appropriate as it takes into account the strength of the concrete. The results of this study demonstrate that GPC is a more efficient and sustainable alternative to conventional concrete materials with superior mechanical properties and a significantly reduced environmental impact.
Graphical abstract