Abstract:
Forty-five high-strength concrete (HSC) prisms were heated, and the exposed temperatures were respectively 20℃, 200℃, 400℃, 600℃ and 800℃. Then the uniaxial dynamic compressive tests of prisms were conducted at strain rates of 10
-5 s
-1, 10
-3 s
-1 and 0.067 s
-1. The results show that cracks will appear in HSC and that the meso-structure of HSC becomes loose as the elevated temperature increases. The HSC damage caused by the elevated temperature increases with the increasing exposed temperature, yet the strain rate has no obvious influence on the elevated temperature damage of HSC. The relative compressive strength of HSC after the same elevated temperature damage increases with the increase of its strain rate. The HSC damage after elevated temperatures caused by the axial strain appears to be a slow and a quick increase before and after the peak strain, respectively. The higher the elevated temperature is, the smaller the HSC damage corresponding to the peak strain becomes, yet the change tendency of the HSC damage after exposure to the same elevated temperature at different strain rates is not obvious. The equations for the elevated temperature damage and the relative compressive strength after elevated temperature damage of HSC are established based on experimental and theoretical analyses.