Experimental investigation and modelling of the mechanical properties of palm oil fuel ash concrete using Scheffe’s method

Abstract

This study explores the enhancement of mechanical properties in concrete blended with palm oil fuel ash (POFA) through Scheffe's optimization. The utilization of POFA as supplementary cementitious material in concrete has gained attention for its potential environmental benefits. Utilizing a (5,2) simplex-lattice design, a systematic approach is employed for optimizing mixture proportions based on response parameters. The laboratory tests to evaluate concrete's mechanical behavior were conducted using the computed mixture ratios from the design experimental points after 28 days of hydration. The results showed maximum flexural strength at 8.84 N/mm2 and compressive strength at 31.16 N/mm2, achieved with a mix of 0.65:0.54:2.3:3.96:0.35 for cement, water, coarse aggregate, fine aggregate, and POFA. Additionally, maximum splitting tensile strength reached 8.84 N/mm2 with a mix of 0.62:0.55:2.09:3.86:0.38 for the same components. Conversely, the minimum flexural, splitting tensile and compressive strength within the experimental factor space was 4.25, 2.08 and 19.82 N/mm2 respectively. The results obtained indicated a satisfactory mechanical strength performance at POFA replacement of 35 percent in the concrete mixture. The developed mathematical model was statistically validated using analysis of variance (ANOVA) at a 95% confidence interval which showed satisfactory prediction performance. The findings from this study provide valuable insights into optimizing POFA-blended concrete for enhanced mechanical performance, offering potential sustainable solutions for the construction industry.