Effect of Bentonite & Polypropylene Fibres on Fresh and Hardened Properties of Geopolymer Concrete with Slag and Alkali Solution

The construction industry significantly contributes to global CO 2 emissions and environmental impact, mainly due to concrete usage, which consumes vast resources and energy while emitting CO 2 . Researchers are exploring alternatives such as geopolymer concrete (GPC), formed without traditional cement but through alkaline activation of industrial by-products like fly ash, ground granulated blast furnace slag, bentonite, and metakaolin clay. This study evaluates the effects of incorporating bentonite and polypropylene (PP) fibers on the workability and strength properties of GPC based on slag. Bentonite substituted 10% of slag, and PP fibers were added at varying ratios (0.5%, 0.75%, and 1%). Both untreated and heat-treated bentonite, heated up to 200°C, were used. Workability was assessed using a slump cone, while mechanical properties, including compressive, split-tensile, and flexural strength, were analyzed. Notably, heat-treated bentonite and PP fibers exhibited significant enhancement in the mechanical properties of the GPC mixes.