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对45个高强混凝土(HSC)棱柱体进行高温加热,温度分别为20℃、200℃、400℃、600℃和800℃。然后对棱柱体进行高温后轴向动态受压试验,应变率分别为10~(-5) s~(-1)、10~(-3) s~(-1)和0.067 s~(-1)。结果表明:随着经历温度的升高,HSC将会出现裂缝,细观结构变得松散;高温对HSC造成的损伤随温度的升高而增大,而应变率对高温后HSC的损伤没有明显影响;经历相同的高温损伤后,HSC的相对受压强度随应变率的增大而增大;轴向应变对高温后HSC造成的损伤在峰值应变前缓慢增大,达到峰值应变后迅速增大;温度越高,峰值应变对应的HSC损伤越小,而经历相同温度后不同应变率下峰值应变处HSC损伤的变化趋势并不明显。基于试验及理论分析,建立了HSC高温损伤以及高温损伤后相对受压强度的计算公式。
Forty-five high-strength concrete (HSC) prisms were heated at high temperatures of 20 ℃, 200 ℃, 400 ℃, 600 ℃ and 800 ℃ respectively. Then the prismatic specimens were subjected to axial dynamic compression tests at high temperature. The strain rates were 10 -5 s -1, 10 -3 s -1 and 0.067 s -1 respectively ). The results show that as the temperature increases, the cracks will appear in the HSC and the mesostructure becomes loose. The damage caused by high temperature to HSC increases with the increase of temperature, while the strain rate has no obvious damage to HSC after high temperature The relative compressive strength of HSC increased with the increase of strain rate after the same high temperature damage. The damage caused by axial strain to HSC after high temperature increased slowly before the peak strain and rapidly increased after reaching the peak strain The higher the temperature, the smaller the HSC damage corresponding to the peak strain. However, the trend of HSC damage at the peak strain at different strain rates is not obvious after the same temperature. Based on the experimental and theoretical analysis, the formulas for calculating the relative compressive strength of HSC after high temperature damage and high temperature damage were established.