Synergistic utilisation of waste coconut fibers, sugarcane bagasse ash, and recycled aggregates in geopolymer paver blocks

The use of industrial and agricultural waste such as ground granulated blast furnace slag (GGBS), recycled coarse aggregates (RCA), sugarcane bagasse ash (SCBA), and waste coconut fibers (WCF) have great potential in development of sustainable construction materials. In this study, geopolymer paver blocks were prepared with GGBS and SCBA as precursors, natural coarse aggregates (NCA) partially replaced with RCA as filler material, and WCF used as an additive. To understand the synergy of these materials, SCBA and WCF was incorporated in a fixed dosage, with varying replacement rates of RCA. GGBS was replaced with 20% SCBA, NCA was replaced with 25% and 50% RCA, and a constant dose of 1% WCF was incorporated in the geopolymer mix. The developed paver blocks were tested for compressive strength, split tensile strength, flexural strength, resistance to abrasion, and water absorption. The results obtained demonstrate that addition of RCA, SCBA, and WCF do not benefit the compressive strength, split tensile strength, and water absorption of the paver blocks. However, the flexural strength and resistance to abrasion have shown significant improvement in the presence of RCA, WCF, and SCBA. This research also develops linear regression models to predict strength properties and water absorption of the paver blocks. The results indicate that linear regression model can be used to predict the compressive strength, split tensile strength, and flexural strength with an accuracy of 85%, 96%, and 71%, respectively. Overall, the developed geopolymer paver blocks with RCA, SCBA, and WCF meet the standard requirements of IS 15658: 2021 for pavement applications, and a significant improvement in the flexural strength and resistance to abrasion will enhance the durability and longevity of the paver blocks in service.