Effect of exposure time and elevated temperature on ordinary concrete

The concrete material in structures is likely to be exposed to elevated temperatures during fires. In this paper, an experimental investigation is carried out to study the effect of different exposure temperatures and times on the mechanical properties of ordinary concrete. Cylinders with a diameter of 100 mm and a height of 200 mm were used as concrete specimens, which were tested at the three elevated temperatures of 200, 400 and 600°C for various times from 1 to 6 h. It was found from the experimental results that the temperature of exposure is the main contributor to the decrease in the weight and compressive strength of concrete and the exposure time has little effect. Although the effect of exposure time on weight loss is greater at lower temperatures than that at higher temperatures, after 3 h of exposure time, the difference becomes negligible. In addition, it was found that the relative compressive strength of concrete remains unchanged for exposure times exceeding 3 h. The numerical simulations were conducted using Abaqus. The predicted temperature distributions agree well with the experimental results.