Experimental Investigation of the Effect of Nanosilica on the Mechanical Properties and Durability of Slag Geopolymer Concrete

Today, the use of nanomaterials in various sciences has found a wide perspective. In this regard, nanoscale additives in the concrete industry with the aim of improving the mechanical properties and durability of concrete, have been considered by researchers. In the preparation of geopolymer concrete, materials containing abundant aluminosilicate materials are combined with alkaline solution. In this laboratory study, a mixing design was made of control concrete containing Portland cement. Then, slag geopolymer concrete was made in three mixing designs containing 0, 4 and 8% nanosilica (4 mixing designs in total). Then, SEM test at 90 days of curing age and tests of water permeability, compressive strength and modulus of elasticity at 7 and 28 days of curing at room temperature were performed on concrete samples. Laboratory results indicate that increasing the curing age of concrete has improved the results of compressive strength, modulus of elasticity and water permeability. In the test of water permeability, modulus of elasticity and compressive strength, the addition of 8% nanosilica to geopolymer concrete improved the results by 26, 13 and 19%, respectively, compared to the design of nanosilica-free geopolymer concrete at 28 days after curing.