Evaluation of fly ash-based geopolymer concrete incorporating coarse and fine recycled aggregates

Geopolymer concrete (GC) is emerging as a promising material as it has a lower carbon dioxide footprint than conventional Portland cement concrete. One of the ways to further enhance the sustainability of GC is by incorporating recycled aggregate (RA). The focus of this study was on evaluating the performance of GC made with coarse recycled aggregate (CRA) and fine recycled aggregate (FRA). The compressive strength and long-term durability properties of GC mixes made with different amounts of CRA and FRA were evaluated. All the GC mixes were also subjected to ultrasonic pulse velocity and electrical resistivity tests. The results showed that FRA content above 25% and 50% CRA had an adverse impact on the long-term durability properties of the GC. The GC mix with 50% CRA and 25% FRA showed compressive strength and electrical resistivity values similar to those of GC made with natural aggregate. The findings from this study are expected to provide valuable insights into the optimal use of RA in GC and contribute to the broader goal of developing sustainable construction materials.