Comparative Study of Green Concrete and Conventional Concrete on Strength and Durability Properties

Green Concrete is a resource-saving structure that reduces environmental impact, carbon dioxide emissions, and waste water. Here comparative evaluation of strength and durability properties of conventional concrete and green concrete incorporating recycled coarse aggregates and fly ash. In the laboratory total of three series of concrete mixtures were prepared. Series I, II and III were prepared with the water to cement (W/C) ratio of 0.3, 0.4 and 0.5 respectively. Each Series, comprises of 3 concrete types named as conventional concrete mixture with 0% RCA and 0% flyash indicated by notation R0. Recycled concrete mixture with 50% RCA and 0% flyash indicated by notation R50. And green concrete mixture with 50% RCA and flyash was incorporated as 25% replacement to cement indicated by notation R50F25. As per IS 10262 1982 and IS 456 the mix design of concrete for all mix proportions is done. A marginal reduction in compressive strength and tensile strength has been noticed in the case of green concrete (10 to 12%). And this may be due to lesser angularity index of recycled aggregates. A large reduction in tensile strength of 25% was noticed in recycled aggregate concrete compared to conventional concrete. This may be attributed to less binding of aggregates in the case of recycled aggregate concrete. Results shows that water absorption, Chloride ion permeability and sorptivity of concrete [R50] increased due to the intrinsic porosity of RCA compared to conventional concrete [R0]. And water absorption, chloride ion permeability and sorptivity of Green concrete [R50F25] is almost same as conventional concrete [R0]. This is due to the pozzolanic action of flyash present in green concrete. Green concrete shows Moderate rate of chloride ion permeability for W/C of 0.3 and 0.4 slightly high rate of chloride ion permeability for W/C of 0.5.