Alkali-Silica potential in fly-ash-based geopolymer concrete

Geopolymer concrete (GPC) is a cutting-edge, environmentally friendly substance which replace cement, resulting in a significant decrease in carbon emissions and encouraging the adoption of more sustainable construction methods. The objective of this study is to evaluate the likelihood of Alkali-Silica Reaction (ASR) occurring in geopolymer concrete by using local aggregates, sourced from various places. The examination was conducted while employing the ASTM C 1260 test method, which entailed measuring the expansion of test bars over a period of 150 days. Additionally, compressive strength testing is performed by casting cubes, and flexural strength tests were performed by casting prisms. In addition, samples of ordinary Portland cement (OPC) were subjected to testing for comparison. The findings demonstrated that the expansion of GPC bars adhered to the limitations set by ASTM C 1260, with an expansion rate of less than 0.025% after 28 days. On the other hand, the OPC samples showed ASR growth that was greater than 0.2% after 28 days, which went over the limitations set by the ASTM standard. Furthermore, the GPC samples exhibited a notable enhancement in both compressive and flexural strength, with compressive strength showing a 15–25% improvement and flexural strength increasing by 5–15% even in harsh environmental conditions. However, OPC samples exhibited a decrease of up to 6% in compressive strength and 5% in flexural strength under same conditions. The findings indicate that geopolymer concrete provides greater resistance to ASR, improved durability, and an extended lifespan in comparison to OPC.