Performance of Recycled Fine-Aggregate Concrete Using Novel Mix-Proportioning Method

Abstract

The construction sector is mainly accountable for the diminishing of natural resources and environmental imbalances due to unplanned mining activities. In this context, use of recycled fine aggregate (RFA) from construction and demolition (C&D) waste can be considered as an effective elucidation. Conventional mix proportioning of RFA in concrete can not be used. To address this issue, a novel mix-proportioning method is developed using particle packing density and minimum paste theory. Fresh and hardened properties of newly developed mix were evaluated. Life-cycle cost analysis (LCCA) was also performed to evaluate the efficacy of the developed concrete using RFA. The result shows that the developed mix design uses lesser quantities of cement and fine aggregates. Replacement of about 30% river sand (RS) by RFA was found optimum. The increase in compressive, flexural, and splitting tensile strength and modulus of elasticity at 56 days was by 11.0%, 9.7%, 3.8%, and 4.0%, respectively. It is concluded that both RS and RFA concrete mix showed superiority in terms of CO2-e and cost compared with conventional concrete.