Effect of aggregate on high-strength concrete in fire

Aggregate is a significant factor that affects the behaviour of high-strength concrete (HSC) in fire. Herein, the during-fire damage, namely explosive spalling, of 33 HSC specimens was experimentally studied to identify the effect of aggregate on HSC in fire. Four types of aggregate including dolomite, quartzitic gravel, granite and sandstone were mixed in the concrete specimens and their design strengths were all 90 MPa. In the heating tests, the fully saturated specimens were subjected to an oven-heating condition (2°C/min) or a simulated standard fire condition (BS 476) respectively. Results indicated that there was no effect of the type of aggregate on the spalling mode of HSC in fire. However, obvious effects of various types of aggregate on the spalling degree of HSC in fire were pointed out, and subsequently a spalling self-prevention concept was introduced to explain it.