PVA fiber-reinforced geopolymer mortar made with hybrid recycled aggregates: Toward thermal insulation, lightweight and improved durability

Polyvinyl alcohol (PVA) fiber-reinforced geopolymer mortar minimizes the shortcomings of large drying shrinkage and high brittleness of conventional geopolymer mortar made with natural sand. Replacing natural sand with crushed glass (CG) and crumb rubber (CR) aggregates is a sustainable alternative. However, their collaborative role in the performance of PVA fiber-reinforced geopolymer mortar remains unclear. To fill this gap, this research investigated the performance of a novel geopolymer mortar reinforced with 0-0.6 vol% PVA fibers and made with CG and CR aggregates with a mix ratio of 10:0-0:10. Due to different physical properties, CG and CR aggregates worked together to control their respective disadvantages. Compared to 100% CG, incorporating 30%-100% CR reduced the hardened density by 8.33%-27.13% and the thermal conductivity coefficient by 44.37%-82.17%. For 0.6 vol% PVA fibers, the 28-d drying shrinkage and 364-d alkali-silica re-action expansion decreased by 10.24%-35.20% and 60.71%-72.50%, respectively.