Sustainable self-compacting concrete incorporating fly ash and rice husk ash: experimental, statistical, and...

The manufacturing process of normal concrete is highly responsible for producing carbon dioxide, resulting in a larger carbon footprint, thus leading to the need for alternative materials to be used in the construction industry. The current research focuses on analyzing the impact and effect of the addition of fly ash (FA) and rice husk ash (RHA) as partial substitution of ordinary Portland cement (OPC) in high-performance self-compacting concrete (SCC). The study evaluates the fresh properties (slump flow, L-box, and V-funnel), mechanical properties (compressive, split tensile, and flexural strength), and durability properties (water absorption, acid, sulfate, and saline water resistance). A Response Surface Methodology (RSM) based Box-Behnken design was employed to analyze the influence of OPC, FA, and RHA proportions and to optimize mix performance. According to the findings, the most efficient ternary combination (OPC 75%, FA 15%, and RHA 10%) obtained better performance with compressive strength of 52.6 MPa, split tensile strength of 4.7 MPa, and flexural strength of 6.1 MPa at 90 days. Additionally, from Life Cycle Assessment (LCA), there was a decrease in carbon dioxide emissions by 119.25 kg/m³, as well as reductions in energy, water use in comparison to control mix of SCC. The use of ternary blend with the optimized combination resulted in a cost reduction of 9.3%compared to the control mix. These results indicate the substantial possibilities of FA-RHA composite SCC in promoting sustainability and sustainable development, thus providing a solution to support circular economy approaches and minimize environmental impacts in contemporary construction projects.