沥青混合料等应变率压缩试验的时间依赖性模型

为描述沥青混合料在受力状态下的时间依赖性行为,以等应变率压缩试验曲线特点为依据,建立沥青混合料的可变量本构模型,并推导出不同加载条件下本构方程表达式.通过有效的数值拟合方法获取沥青混合料的本构模型参数,将该模型与三轴等应变率压缩试验曲线进行对比,两者吻合较好,表明可变量本构模型能较好地描述沥青混合料与时间依赖行为,对破坏失效后材料的力学行为曲线有较好地表述.利用拟合参数计算蠕变曲线,其计算蠕变曲线能成功地描述蠕变的第二、三阶段,曲线特点与应力、温度等条件相关,在高温度和高应力条件时达到一定应变条件时所需时间较短,同时稳定期随温度和应力的增加所经历的时间逐渐减少.

Time-Dependent Constitutive Model of Asphalt Mixtures Based on Constant Strain Rate Tests

In order to study the time-dependent behavior of asphalt mixtures, the paper developed a variable compliance model and established the mathematical expressions of the constitutive equation based on the characteristics of constant strain rate curves. The parameters of asphalt mixtures were acquired by an effective method. The results of the model were agreed with the data of triaxial con- stant strain rate tests perfectly. It was indicated that the constitutive model could efficiently describe the time-dependent and the post-failure behavior of asphalt mixtures. The creep curves which were obtained by fitted parameters could express the secondary and tertiary phase accurately. The proper- ties of creep curves were decided by stress and temperature. It was spent less time to achieve a certain strain under the condition of high stress and temperature, while the time of steady-state phase was less with the stress and temperature increased.