Efficacy of geopolymerization for integrated bagasse ash and quarry dust in comparison to fly ash as an admixture: A comparative study

Abstract

This study compares the efficacy of geopolymerized bagasse ash (GB) and geopolymerized quarry dust (GQ) with traditional flay ash-based geopolymer considering the strength properties of a subgrade. Geopolymerized composited binary admixture (GBA) was constituted by incorporating the optimum percentages of GQ and GB, on the basis of a maximum reduction of 70% and 52% in plasticity index value respectively. Then samples for strength tests such as unconfined compression tests and California bearing ratio tests were remolded using standard and modified compaction parameters. Also, the mineralogical and microstructural analyses were conducted based on SEM and EDS. The influence of curing and percentage of geopolymers was also investigated on strength properties. The performance of GBA is equivalent to traditional fly-ash-based geopolymer (GF) considering strength properties like q_u and CBR ensuring more than 200% increase in the strength at 20% and 15% content respectively. However, at these contents, the ductility of GBA-treated samples is 107% higher than GF making this geopolymer more suitable under dynamic load. Formation of geopolymer gel ((N, C)-A-S-H) is confirmed by microstructural and elemental analyses but the microstructure of GBA treated sample is more porous than the microstructure of GF treated sample, which provides some advantage for particles reorientation of GBA treated sample under load before failure. Also, the proposed multi-waste geopolymer has significant implications for waste management, as its implementation for the construction of a two-lane subgrade covering a distance of 1 kilometer may enable the repurposing of 1313 tons of assorted solid waste.