Utilization of agricultural, industrial waste and nanosilica as replacement for cementitious material and natural aggregates - Mechanical, microstructural and durability characteristics assessment.

This study examines the effect of rice husk ash (RHA) and nanosilica, and ground granular blast furnace slag (GGBS) on concrete mechanical and durability properties. The cement had been partially replaced with nanosilica and RHA having substitution percentages up to 6% and 10% respectively whereas the sand had been partially replaced by GGBS at 20% for all mixes. A water-to-cementitious materials ratio of 0.38 and a sand-to-cementitious materials ratio of 2.04 were used to cast eight different concrete mixes. The nanosilica used in the present research possessed some favorable effects such as rich fineness, higher surface area and greater reactivity which signified one of the best cement replacement materials. Both the durability and strength of concrete specimens possessing nanosilica, RHA and GGBS was evaluated using in-elastic neutron scattering, SEM image, piezoresistive test, split tensile strength, flexural strength and compressive strength test. Concrete specimens were also subjected to chloride penetration and water absorption to examine the impact of replacement materials on the concrete's durability attributes. Concrete performance was increased by the ternary blending of concrete because of the active participation of nanosilica in durability and strength at early ages, both RHA and GGBS played an important role in improving packing density. It was found that as the percentage of cement replaced with nanosilica increases, the durability of concrete also significantly increases. But the optimum strength parameter was found when 4% of cement was replaced by the nanosilica effectively. The proposed ternary mix may be eco-friendly by saving cement and enhancing strength and durability effectively.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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