中文摘要：

现有力学模型不能全面描述沥青混合料的蠕变,因此根据沥青混合料三阶段的蠕变特性,对Burgers模型中表征粘性流动的外部粘壶进行改进,认为其粘滞系数先增大后减小.推导了改进模型的本构方程,得到了蠕变应变、蠕变速率和蠕变加速度的解析表达式;运用最小二乘原理,建立了模型参数的确定方法;通过两个实例验证了改进模型的正确性.研究表明改进模型拟合曲线与实测应变吻合较好,相关性系数高,而且计算得到的流变时间与实测流变时间误差较小,说明该力学模型能够反映下沥青混合料第三阶段的蠕变,而流变时间Ft可作为研究沥青混合料蠕变性能的一个重要指标.

英文摘要：

The existing mechanics model can not describe the overall creep of asphalt mixture,so based on the three-phase creep character of asphalt mixture,the dashpot of Burgers model was modified and its viscosity coefficient first increased then decreased.Then,constitutive relationship of the improved model was deduced,and the expressions of creep strain,creep rate and creep acceleration were also given.Meantime,creep rupture time was defined as the creep stability criterion by analyzing the stability of the modified model and parameters determination method was established by the principle of least square.Finally,the proposed model was verified through two experimental studies.It is indicated that the modified model can clearly describe the three-phase creep,especially the accelerating creep stage,and creep rupture time can also be used as a important index to research the creep character of asphalt mixture.The research puts forward a new thought for studying the creep character of asphalt mixture.