Thermomechanical evaluation of sustainable foamed concrete incorporating palm oil fuel ash and eggshell powder

Increased usage of concrete contributes to urban thermal discomfort due to the Urban Heat Island effect. At the same time, the corresponding increased consumption of cement also causes a significant rise in carbon dioxide (CO2) gas emissions. This experimental work aims at evaluating the thermal and mechanical performance of 1800 kg/m3 dry density green sustainable foamed concrete (GFC) incorporating agroindustrial waste such as Palm Oil Fuel Ash (POFA) and Eggshell Powder (ESP) as supplementary cementitious materials (SCMs). The POFA content varied from 15 to 35%, with increments of 5%, while being supplemented with 5% ESP. To evaluate the performance of the developed GFC, the flowability, mechanical strengths (compressive and splitting tensile strengths), and thermal performances (thermal conductivity and surface temperature) were investigated. Incorporation of 15-25% of POFA supplemented with 5% ESP as partial cement replacement materials resulted in enhanced mechanical strengths. Although usage of POFA can reduce the thermal conductivity, the POFA content must be limited to 15–25% to prevent excessive heat absorption by the exterior surface of the concrete. Overall, the optimum use of 15% POFA in a combination of 5% ESP is desirable to produce an eco-friendly sustainable foamed concrete.