Residual compressive strength of <scp>EPS</scp> lightweight concrete under heating–air cooling regime

Abstract This paper presents an experimental study on the evolution of the residual compressive strength of expanded polystyrene (EPS) lightweight concrete submitted to different heating–air cooling regimes. Cubic concrete specimens with three EPS volume fractions (10%, 30%, and 50%) and three EPS beads diameters (2, 4, and 6 mm) were tested. Various temperature plateaus were applied ranging from 100 to 700°C by steps of 100°C, with an average temperature rise rate of 5°C/min. The plateaus were kept maintained for 2 h. Then, a compressive test was performed on each lightweight concrete specimen after allowing it to cool down to room ambient temperature for 24 h. The results showed a significant decrease in the EPS concrete residual compressive strength with increasing EPS volume fraction. Further, it was observed that the variation in the EPS beads diameter for the same volume fraction of polystyrene has a small effect on the residual compressive strength of EPS concrete. Finally, it was found also that lightweight concrete retains 80% of its strength at ambient temperature up to the plateau temperature of 500°C followed by an important degradation above 500°C.