High-strength steel fibre-reinforced geopolymer concrete utilising recycled granite waste and rice husk ash

Abstract

A limited number of research studies have managed to attain high-strength geopolymer concrete, especially by utilising waste materials. In this study, granite waste (GW) from the mining industry, which contaminates the surrounding environment and causes air pollution, and rice husk ash (RHA) from agricultural waste were used to produce high-strength steel fibre-reinforced geopolymer concrete (HSFRGC). To reduce natural sand consumption, GW was utilised as a fine aggregate. RHA was added at 0%, 1%, 3%, and 5% by weight of coal fly ash to enhance the properties of HSFRGC. In addition, hooked-end steel fibres were employed as reinforcement at 0%, 0.5%, and 1% by volume of the concrete. The objective of this study is to investigate the effect of incorporating GW and RHA into HSFRGC, examining properties such as workability, strength, durability, and microstructure. Additionally, an assessment was conducted on the environmental impact and cost-effectiveness of the HSFRGC system with additives to determine its feasibility for practical scenarios. The results showed that the addition of 1% RHA as an additive in the geopolymer system, which led to microstructural homogeneity in the geopolymer matrix, could effectively enhance the mechanical properties and durability. Moreover, the addition of hooked-end steel fibres along with 1% RHA further improved the mechanical performance compared to samples without steel fibres, increasing both compressive strength by 25% and flexural response by 70%. Meanwhile, incorporating 1% RHA in mixtures could assist in mitigating chloride migration by approximately 10% due to the filler effect occurring in the geopolymer matrix. Regarding to environmental impact and cost-effectiveness, the incorporation of 1% RHA and 0.5% steel fibre demonstrated a suitable balance, exhibiting eco-strength efficiency with an increase of 15% compared to plain geopolymer concrete, making it a reasonable choice for both environmental concerns and cost efficiency.