Enhancing eco-concrete performance through synergistic integration of sugarcane, metakaolin, and crumb rubber: Experimental investigation and response surface optimization

Sustainable construction has gained paramount importance due to the consideration of the devastating effects of construction activities on the environment. Researchers are exploring innovative approaches to mitigate the carbon footprint and enhance the durability of concrete. In order to regulate the demand and cost of concrete constituents, such as cement and sand, there is a need to invent alternative materials and utilize various industrial and agricultural wastes instead of concrete ingredients, either partially or completely. The experimental investigation and optimization of eco-concrete composites by integrating sugarcane bagasse ash (SCBA), metakaolin (MK), and crumb rubber (CR) are cutting-edge research areas that aim to develop environmentally friendly and high-performance concrete materials. The present research work has attempted to utilize SCBA up to 15% by weight of cement with an increment of 5%, MK as a fractional exchange of cement up to 15% with 5% intervals, and CR was utilized as fractional volumetric substitution of sand from 0% to 15% in concrete. Different sets of combinations were evaluated to identify effects on density, workability, compressive strength, split tensile strength, flexural strength, and microstructural properties. This study has obtained satisfactory results when compared to the control concrete for 10% substitution of cement with MK and 10% substitution of cement with SCBA, along with a 10% replacement of fine aggregate (i.e., sand) with CR. The results were analyzed and optimized using Response Surface Methodology (RSM), which illuminated a strong correlation between experimental findings and RSM models, with an R squared (R2) value of 0.9580. The experimental findings and RSM models showed a significant correlation. The increment in the substitution of sand with CR resulted in a decline in strength, and it can be controlled by adopting different effective pretreatment techniques for CR.