冻融循环作用下煤矸石混凝土的损伤特性及本构关系

考虑煤矸石粗骨料取代率（0、20%、40%、60%）的影响，开展冻融循环试验、单轴受压本构试验及声发射检测试验，研究煤矸石混凝土的损伤本构模型。研究结果表明：不同取代率的煤矸石混凝土的相对峰值应变与冻融损伤值具有较高的相关性，所得冻融损伤值与相对峰值应变的方程可为本构模型的建立提供有效参数。煤矸石混凝土声发射特性与其荷载损伤发展情况、力学性能、应力–应变曲线有紧密联系，基于受压声发射特性，采用PBS平行杆力学模型建立了未冻融循环作用下煤矸石混凝土的荷载损伤模型，并结合其冻融损伤模型，建立了煤矸石混凝土冻融损伤本构关系，计算结果与试验数据符合较好。该模型能较准确地反映混凝土在冻融和单轴受压荷载作用下的全过程损伤特征。

Damage characteristics and constitutive relationship of coal gangue concrete under freeze-thaw cycles

Considering the influence of coal gangue coarse aggregate replacement rate (0, 20%, 40%, 60%), this article conducts freeze-thaw cycle test, uniaxial compressive constitutive test and acoustic emission detection test to study the damage constitutive model of coal gangue concrete (CGC). The research result indicates that the relative peak strain of CGC with different substitution rates has a high correlation with the freeze-thaw damage value. The resulting equations of freeze-thaw damage value and relative peak strain provide effective parameters for the establishment of constitutive models. The acoustic emission characteristics of CGC are closely related to its load damage development, mechanical properties, and stress-strain curve. Therefore, based on the acoustic emission characteristics under axial compression, this paper uses parallel bar system (PBS) to establish the load damage model of gangue concrete without freeze-thaw cycle. Combined with the damage model of freeze-thaw, the freeze-thaw damage constitutive relationship of CGC is established, and the calculation results are in good agreement with the test data. This model can accurately reflect the overall process damage characteristics of CGC under freeze-thaw and load damage under axial compression.