玄武岩纤维布增强树脂基复合材料约束高温损伤混凝土轴压力学性能

对36个玄武岩纤维布增强树脂基复合材料（BFRP）约束加固的高温损伤混凝土圆柱体和15个不同高温损伤的对比试件进行了轴压试验。试验表明，BFRP侧向约束能显著改变混凝土圆柱体的破坏形态，提高混凝土圆柱体的轴压强度和变形能力。其中二层BFRP包裹的200℃、400℃、600℃和800℃高温损伤混凝土圆柱体的轴压强度分别提高了56%、82%、234%和250%，轴向变形分别提高了328%、198%、232%和136%。采用典型的纤维增强复合材料约束常温未损伤混凝土轴压强度和变形计算模型预测纤维增强复合材料约束高温损伤混凝土轴压极限强度和极限变形时存在较大的偏差。基于本文试验数据，确定了BFRP约束高温损伤混凝土极限应力和极限应变计算模型中与温度相关的参量，建议了适用于预测纤维增强复合材料约束高温损伤混凝土的极限应力计算模型和极限应变计算模型。

Axial compressive behavior of basalt fiber reinforced polymer-confined damaged concrete after exposed to elevated temperatures

An experimental study on the axial compressive behavior of 36 elevated temperature damaged and 15 unheated concrete cylinders wrapped with basalt fiber reinforced polymer(BFRP) sheets was conducted. The test results show that confinement can significantly change failure mode, improve the strength and ductility of elevated temperature damaged concrete cylinders. After confined with two layers of BFRP sheets, the strength of the cylinders damaged by 200℃, 400℃, 600℃ and 800℃ increases by 56%, 82%, 234% and 250%, respectively; And the axial deformation increases by 328%, 198%, 232% and 136%, respectively. The typical ultimate stress models and ultimate strain models for FRP-confined undamaged concrete are not suitable for confined elevated temperature damaged concrete cylinders. Based on the test results, variables for calculation of ultimate stress and ultimate strain are determined, and ultimate stress model and ultimate strain model of confined elevated temperature damaged concrete cylinders are proposed.