Performance of high strength concrete containing locust bean pod ash as cement replacement

Abstract

High-strength concrete (HSC) is becoming popular as a result of its great strength and superior durability. Despite the fact that several supplementary cementitious materials (SCMs) have been explored in HSC, the use of locust bean pod ash (LBPA) as an SCM has not been considered. This study evaluated the use of LBPA as an SCM in HSC. The locust bean pod (LBP) underwent a two-hour calcination process in a furnace at a temperature of 600 °C. At 5%, 10%, 15%, and 20% by weight of cement, LBPA was used in place of cement. The slump, strength (compressive: 100 × 100 × 100 mm cubes; flexural: 100 × 100 × 400 mm beam, and splitting tensile: 100 × 200 mm cylinder at 28 days), water absorption, resistance to sulfate and the effects of elevated temperatures were assessed. Mechanical properties of the concrete were statistically analyzed and optimized using linear Regression. The results showed that 5% LPBA replacement improved compressive, flexural and tensile strengths by 13.14%, 6.42% and 7.08% respectively over the control samples. Additionally, LBPA improved the performance of concrete against water absorption, sulphate attack, and elevated temperatures. The optimized model of 15% LBPA had the highest accuracy with percentage errors of 5.89% and 2.78% for compressive and flexural strengths respectively, while 5% had the highest accuracy for tensile strength with percentage error of 3.08%. The study concludes that LBPA can be successfully used as an SCM in HSC, with a 10% recommended optimum replacement amount.