Performance of reactive powder concrete slender columns exposed simultaneously to eccentric load and elevated temperatures

The objective of this study is to examine the impact of elevated temperatures on the structural response of slender columns made of reactive powder concrete (RPC) subjected to eccentric axial loads. Nine RPC column specimens were exposed to a temperature at three different levels: 450 °C, 600 °C, and 750 °C, and to three eccentricities: 50 mm, 100 mm, and 150 mm. The columns underwent fire exposure while being subjected to axial loading equal to 60% of their ultimate capacity. The outcomes of the experimental tests indicate a noticeable lateral displacement of the RPC columns at high temperatures. The results show that at a constant temperature 750 °C, the mid-height lateral buckling for various eccentricities is significantly higher comparing 50 mm with 100 mm and 150 mm by 59% and 81%, respectively. While this rate becomes 36% and 35% for 600 °C. At 750 °C, the lateral mid-height buckling is found to be significantly greater when compared to 450 °C and 600 °C by 106% and 69%, respectively (for 50 mm eccentricity). While the ratio becomes 48% and 46% (for 100 mm eccentricity), one of the main findings in the research is that a low eccentricity value 50 mm, which has a high load, gives higher buckling for each elevated temperature. The mode of failure regarding the column depended on the eccentricity value where the high eccentric loaded columns showed prolonged ductile behavior, while the least eccentric loaded columns showed a brittle type of failure.