Alkali Silica Reaction in Geopolymer Recycled Aggregate Concrete

Abstract

This thesis states the outcomes of an experimental study aimed to compare alkali silica reaction’s (ASR) mechanism by evaluating its damage in conventional concrete and geopolymer concrete. Geopolymer mortar specimens were prepared using fly ash of class F, slag with natural and recycled aggregate. Mechanical tests included accelerated mortar bar test, tests for compressive and flexural strength which were conducted according to ASTM standard. Findings suggested that in the presence of reactive aggregates, the extent of ASR reaction in geopolymer mortar which is based on fly ash is six times lesser than the mortar, which is based on OPC, and significantly below 0.11% which is the threshold specified by ASTM. Additionally, samples consisting of geopolymer mix turned out to go through a densification process during the existence of alkali solutions, due to which permeability was decreased and mechanical strength. The results show the mechanical properties are same for both OPC and GPM. Using aggregates which are at risk of having ASR while creating geopolymer concrete items can add to the financial allure and sustainability of geopolymer concrete in areas where the local supply of aggregates having high quality is lower.