Influence of elevated temperatures on the mechanical properties and microstructure of self consolidating lightweight aggregate concrete

► Fresh and hardened self compacting lightweight concrete properties were determined. ► All mixtures were also characterised after exposure to elevated temperatures. ► Lightweight aggregate type and water/powder ratio affect these properties. ► Thermal cracking patterns were observed by ESEM after thermal exposure. Self consolidating lightweight concrete (SCLWC) mixtures were prepared by using two different lightweight coarse aggregates and by replacing normal weight crushed coarse limestone aggregate at a constant water/powder ratio. One of the SCLWC mixtures was also prepared at different water/powder ratios. All the mixtures were exposed to 300, 600 and 900°C, respectively. Lightweight aggregate type and water/powder ratio affect water transport characteristics and resistance of the mixtures to elevated temperatures. The microstructural investigation findings are consistent with thermal strain and residual mechanical properties of the mixtures after exposure to high temperatures.