Hybrid fibre reinforced eco-friendly geopolymer concrete made with waste wood ash: A mechanical characterization study

On reducing greenhouse gas emissions by the cement industry, geopolymer with an amorphous polymer form was the best alternative. Geopolymer concrete (GPC) was weak in impact strength, brittle, ductile, and energy absorption than conventional cement concrete. Various property fibres with the capacity to improve the aforementioned properties of GPC can be added. Polypropylene fibre with low elastic modulus and waste tire rubber fibre with high elastic modulus was used in this research to improve energy absorption and impact strength. Different modulus fibres such as polypropylene and rubber was added by 0%, 0.5%, 1%, 1.5% and 2% of volume fraction. The effects of adding individual fibres on the mechanical property of eco-friendly geopolymer concrete were studied. In addition, the influence of hybrid fibres on the mechanical features of low-calcium geopolymer concrete was assessed. The research results revealed that the hybridization of 0.5% of polypropylene fibre and 0.5% of rubber fibre showed better performance and achieved maximum strength in all mechanical features such as compressive, flexural, and splitting tensile behaviour. Meanwhile, the optimum hybrid fibres increased the mechanical features by 23.9%, 12.0%, and 15.2%, respectively, at the 28 days of curing ages compared to geopolymer concrete without fibres.