循环荷载作用下沥青混合料的黏弹塑性损伤本构模型

为较好描述损伤状态下沥青混合料的黏弹塑性应力-应变关系、明确动态循环荷载对其损伤本构关系的影响，利用经典黏弹塑性流变理论，在Burgers黏弹性模型上串联一个黏塑性元件，并根据损伤力学应变等效原理，建立了一个能体现动态循环荷载作用特点及能考虑加载频率影响的沥青混合料黏弹塑性损伤本构模型.同时进行间接拉伸疲劳试验，研究加载频率、环境温度、应力水平、沥青用量及沥青种类对混合料应力-应变关系的影响，并标定模型参数、验证模型的有效性.结果表明:所建模型不仅能较好描述沥青混合料在动态循环荷载作用下的损伤本构关系，还能体现加载频率、环境温度及荷载水平等因素对应力-应变关系的影响;模型参数意义明确、规律性强，值得进一步研究和推广.

Viscoelastic-Plastic Damage Constitutive Model of Asphalt Mixture Under Cyclic Loading

In order to better describe the viscoelastic-plastic stress-strain relationship of asphalt mixture during damage process， and to clarify the effect of dynamic cyclic loading on the damage constitutive relation of the mixture，a viscoplastic element was connected in series to the Burgers viscoelastic model based on the classical viscoelastic plastic rheological theory. According to the strain equivalent principle of damage mechanics， a viscoelastic-plastic damage constitutive model of the asphalt mixture was established， which can reflect the dynamic cyclic loading characteristics and consider the influence of loading frequency. Then the indirect tensile fatigue tests were carried out to study the effects of loading frequency， ambient temperature， stress level， asphalt dosage and asphalt type on the stress-strain relationship of the mixture， and to calibrate the model parameters in order to verify the validity of the model. The results show that the model can not only better describe the damage constitutive relationship of asphalt mixture under dynamic cyclic loading， but also can reflect the influence of loading frequency， ambient temperature and load level on the stress-strain relationship of the mixture. Because the meaning of the parameters in the model is clear and regular， it deserves further research and promotion.