Experimental Investigation of Recycled Plastic Fibre-Reinforced Geopolymer Concrete for Enhanced Durability under Acid, Sulphate and Chloride Exposure

Abstract

The increasing generation of plastic waste and the environmental impact associated with conventional cement production have created a need for sustainable construction materials. This study experimentally investigates the durability performance of recycled plastic fibre-reinforced geopolymer concrete under acid, sulphate, and chloride exposure. Five geopolymer concrete mixes, designated G1–G5, were prepared with recycled plastic fibre contents of 0%, 0.25%, 0.50%, 0.75%, and 1.00%, respectively. The durability performance was evaluated at 7, 14, and 28 days using percentage weight loss after acid and sulphate exposure, residual compressive strength, and Rapid Chloride Penetration Test (RCPT). The results showed that the incorporation of recycled plastic fibres improved the durability performance compared with the control mix. Under acid exposure, G4 containing 0.75% fibre recorded the lowest weight losses of 3.22%, 4.08%, and 4.94% at 7, 14, and 28 days, respectively, while its residual compressive strength reached 48.6 MPa at 28 days. Under sulphate exposure, G4 also exhibited the lowest weight losses of 2.36%, 3.08%, and 4.02% and the highest residual compressive strength of 50.4 MPa at 28 days. The RCPT results further confirmed improved chloride resistance, with G4 recording the lowest charge passed of 2146, 1728, and 1326 coulombs at 7, 14, and 28 days. The improved durability is attributed to the dense geopolymeric matrix and the crack-bridging and crack-arresting action of recycled plastic fibres. Overall, 0.75% recycled plastic fibre (G4) was identified as the optimum content, providing the most favourable combined resistance to acid, sulphate, and chloride-related deterioration.