Effect of high temperatures on physical and compressive strength properties of self-compacting concrete incorporating palm oil fuel ash

Abstract

Palm oil fuel ash (POFA) has been widely utilized to replace cement in self - compacting concrete (SCC) to reduce the cost of its production, environmental pollution and health hazard caused in the cement production. However, the effect of high temperatures on SCC incorporating POFA has not been well established. The purpose of this research is to examine effects of high temperatures on the physical and compressive strength properties of SCC incorporating POFA with replacement level of 20% by weight of cement. The compressive strengths of SCC specimens were evaluated at 28 days of curing using both cubes and cylinders. Thereafter, the SCC specimens were exposed to high temperatures of 200, 400, 600 and 800 °C using an electric furnace for a period of 2 hours after attaining the required temperatures. After exposure, mass losses together with residual compressive strength were determined. The results of the test showed that there was a continuous reduction in mass of the specimens with increase in temperature. The results also revealed that the colour of the specimens does not change at 200 °C but the colour changes started to occur between 400 °C up to 800 °C. There was an increase in the residual compressive strength for the two mixes at temperature range of 200 - 400 °C for the cubes and cylinders whereas at the temperature of 400 - 600 °C and 600 - 800 °C, there was a sharp reduction in the residual compressive strength for the two mixes for the cubes and cylinders. The SCC with and without POFA follow the same trends.