冻融损伤影响下河道再生混凝土本构模型研究

Constitutive Model of Recycled Aggregate Concrete for Channels Affected by Freeze-Thaw Damage

应力-应变的本构关系是混凝土材料重要研究内容。为了揭示冻融循环作用下再生混凝土的力学损伤规律,结合Weibull强度理论与混凝土抗压试验结果,建立了混凝土细观损伤统计模型。试验结果表明:冻融循环损伤作用使得混凝土在单轴荷载作用下破坏程度越来越明显;随着冻融循环次数从0次增加到120次,抗压强度和弹性模量呈指数型衰减规律,且破坏应变呈增大趋势;基于Weibull强度理论构建了考虑冻融循环影响的混凝土损伤本构模型,拟合求解了模型的形状参数m和尺度参数ε0,并将冻融循环次数T引入至该模型中,通过对应力-应变曲线的实测与模型拟合结果进行比较,验证了理论模型的合理性。

The stress-strain constitutive relationship is an important research content of concrete materials.To reveal the mechanical damage law of recycled aggregate concrete under the effect of freeze-thaw cycles, this study builds a statistical model of mesoscopic damage to concrete on the basis of Weibull strength theory and compression experiment results of concrete.The results show that the damage to concrete under the uniaxial load is more significant under the action of the freeze-thaw cycle.As the number of freeze-thaw cycles increases from 0 to 120,the compressive strength and elastic modulus decrease exponentially, and the failure strain shows an upward trend.The Weibull strength theory is employed to construct the constitutive model of concrete damage considering the influences of freeze-thaw cycles, and by fitting, the shape parameter m and the scale parameter ε0are solved.In addition, the number of freeze-thaw cycles T is introduced to this model.The comparison of the measured stress-strain curve with the fitted results of the model verifies the rationality of the theoretical model.