Alternative Fine Aggregates to Natural River Sand for Manufactured Concrete Ensuring Circular Economy

To address SDG12 (ensure sustainable consumption and production patterns), and to provide technical evidence for alternative concrete constituents to traditional natural river sand, stone fine aggregate (SFA), brick fine aggregate (BFA), ladle-refined furnace slag aggregate (LFS), recycled brick fine aggregate (RBFA), and washed waste fine aggregate (WWF), ready-mix concrete plants were investigated. Concrete and mortar specimens were made with different variables, such as replacement volume of natural sand with different alternative fine aggregates, water-to-cement ratio (W/C), and sand-to-aggregate volume ratio (s/a). The concrete and mortar specimens were tested for workability, compressive strength, tensile strength, and Young’s modulus (for concrete) at 7, 28, and 90 days. The experimental results show that the compressive strength of concrete increases when natural sand is replaced with BFA, SFA, and LFS. The optimum replacement amounts are 30%, 30%, and 20% for BFA, SFA, and LFS, respectively. For RBFA, the compressive strength of concrete is increased even at 100% replacement of natural sand by RBFA. For WWF, the compressive strength of concrete increases up to a replacement of 20%. Utilizing these alternative fine aggregates can be utilized to ensure a circular economy in construction industries and reduce the consumption of around 30% of natural river sand.