高温后碳纤维布约束混凝土轴压力学性能试验

通过对20个经历四种不同高温后的素混凝土和无机胶粘贴碳纤维布加固混凝土圆柱体的轴压力学性能试验，研究了无机胶粘贴碳纤维布约束混凝土在经历不同高温后抗压强度、极限压应变和应力-应变关系的变化，得出所经历高温过程对其轴压力学性能的影响。结果表明:无机胶粘贴碳纤维布约束混凝土经历高温后的破坏形态与常温下基本相似；其抗压强度在经历100℃高温后，下降仅5%左右，在经历200℃、300℃和400℃高温后，约为常温试件的85%~90%；无机胶粘贴碳纤维布约束混凝土的极限压应变在100℃高温后略有减小，在200℃~400℃高温后则比常温下增大20%左右；碳纤维约束对核心混凝土抗压强度的提高作用，会随试件所经历温度的升高而逐渐增大；无机胶粘贴碳纤维布约束混凝土的应力-应变曲线在经历高温后会明显趋于扁平，并且多了一个呈上凹状的压密阶段。

EXPERIMENTAL STUDY ON RC CYLINDERS CONFINED BY CFRP SHEETS UNDER UNIAXIAL COMPRESSION AFTER ELEVATED TEMPERATURE

20 short concrete cylinders confined by CFRP sheets with inorganic adhesive after different elevated temperatures have been loaded under uniaxial compression. The failure mechanism and characteristics of the confined cylinders after elevated temperature have been studied. Based on the test results, the effect of the elevated temperature on the ultimate strength and strain, stress-strain relationship of the strengthened members has also been evaluated. The results show the concrete cylinders confined by CFRP sheets with inorganic adhesive after elevated temperature showed the same failure mechanism with the concrete cylinders at normal temperature. The ultimate compressive strength only decreased by 5% after temperature about 100℃ and were about 85%~90% of the specimens at normal temperature after temperature about 200℃~400℃. After elevated temperature about 100℃, the ultimate compressive strain decreased little and after elevated temperature about 200℃~400℃, the ultimate compressive strain increased by 20%. With the increasing of temperatures, the confining effect of CFRP sheets on the concrete increases. After elevated temperature, the stress-strain curves of concrete cylinders confined by CFRP sheets with inorganic adhesive tended to be flat and there was a compact phase in the stress-strain curves.