Desirability analysis of sustainable concrete containing fly ash cenosphere as fine aggregate replacement using RSM approach

An increasing trend involves the creation of modified concrete by substituting traditional concrete components with waste materials. These waste materials encompass fly ash cenosphere as a replacement for M sand as fine aggregate. However, the utilization of fly ash in concrete is constrained by the need to strike a balance between cost and performance. This study delves into the cost benefits of employing fly ash cenosphere concrete, comparing the results to those of conventional concrete. The investigation focuses on assessing the compressive strength incorporating FAC, and this is achieved through the formulation of concrete mixes using Response Surface Methodology (RSM). A Central Composite Design (CCD) based on RSM is employed to analyze how the substitution of FAC (ranging from 0 to 100%) and M sand (ranging from 0 to 100%) influences both the cost of concrete production and its compressive strength. The study develops mathematical models of first and second orders through RSM based on the data generated in the experimental design. The accuracy of these mathematical models established by CCD is verified using Analysis of Variance (ANOVA). Subsequently, desirability analysis is employed to optimize the contents of FAC and M sand, aiming to attain maximum compressive strength while minimizing costs. The evaluation of RSM demonstrates that the empirical findings align well with linear and quadratic models for cost and compressive strength responses, respectively, with coefficients of determination exceeding 0.90 for all responses. The verification of the model findings demonstrates substantial agreement with the verified values. In conclusion, this study confirms that a reasonable balance between cost and performance can be achieved by incorporating FAC.