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为研究冻融劣化混凝土在循环荷载作用下的能量耗散规律及其破坏形态,对强度等级为C30的混凝土立方体(300mm×300mm×300mm)试件进行压缩试验。结果表明,当冻融循环次数不超过10次时,混凝土应力—应变曲线的外包络线呈两段式。当冻融循环次数超过10次时,包络曲线的应力与应变呈现出非线性增长,且这种非线性增长关系随冻融循环次数的增加而趋于明显;当冻融循环次数由10次逐渐增加至35次时,冻融劣化混凝土的破坏形态由剪压破坏逐渐向轴压破坏转变;冻融劣化混凝土试件在循环加卸载过程中耗散能、弹性应变能、塑性应变能的释放规律一致,都经历了前期能量释放缓慢,中期能量释放迅速,后期能量释放趋于平缓的变化阶段。研究成果可为严寒地区的混凝土构件设计及工程实践提供指导。
In order to study the law of energy dissipation and the failure mode of concrete subjected to cyclic loading under freezing-thawing deterioration, compression tests were carried out on specimens of concrete cubes with strength class C30 (300mm × 300mm × 300mm). The results show that when the number of freeze-thaw cycles does not exceed 10 times, the external stress-strain curve of concrete has a two-stage external envelope. When the number of freeze-thaw cycles exceeds 10 times, the stress and strain of the envelope curve show a non-linear increase, and this nonlinear increase tends to be obvious with the increase of the number of freeze-thaw cycles. When the number of freeze-thaw cycles is 10 times Gradually increased to 35 times, the failure morphology of freeze-thaw deterioration concrete gradually changed from shear failure to axial compression failure. The dissipation energy, elastic strain energy and plastic strain energy of concrete under freeze-thaw deterioration during cyclic loading and unloading Consistent with the law, have experienced the early stage of energy release is slow, rapid release of energy in the middle, post-release of energy tends to be flat stage of change. The research results can provide guidance for concrete component design and engineering practice in cold regions.