Compressive strength of lightweight aggregate concrete exposed to high temperatures

In this paper, effects of high temperatures on the compressive strength of concrete were investigated with the aim to produce a fire resistant concrete. Thus, the mixture groups were determined by replacing pumice for ordinary aggregate it the ratios of 25, 50, 75 and 100% in volume. The temperature values were chosen as 150, 300, 450, 600 and 750°C. The efffects of heating duration over the compressive strength were also examined, and the different types of concrete mixtures were heated for one hour, three hours and five hours periods for each temperature values. It was observed that concrete properties were deteriorated at 150°C and the specimens began to lose some of their initial strengths at this temperature. Though a considerable strength lose was not seen between 150-300°C, all types of concrete mixtures continued to lose their compressive strength after 300°C. Every concrete mixture lost a significant part of their initial strength when the temperature is reached up to 750°C. When the lightweight aggregate ratio is increased for each temperature value, the loss of compressive strength of the concrete compared to the initial strength was decreased. It was found that the heating duration does not affect the strength loss significantly but a high temperature is a more significant parameter on the strength loss.