热力耦合作用下浇注式沥青混凝土三轴蠕变特性研究

为了深入研究浇注式沥青混凝土沥青混合料在温度、应力耦合作用下的三轴蠕变特性，采用MTS815试验机开展了不同温度、不同应力水平和不同围压条件下的三轴蠕变试验，获取了相应的蠕变曲线，并将改进的Burgers模型推广到三维形式，用来描述浇注式沥青混凝土的蠕变本构关系。研究结果表明：浇注式沥青混凝土蠕变曲线的第一阶段不明显，这反映出其内部空隙率较低；蠕变变形值随温度升高和偏应力水平增大而明显增大，这反映出高温重载共同作用是浇注式沥青混凝土路面出现车辙的决定性因素；蠕变变形随围压增大略有减小，围压对蠕变变形有抑制作用，三轴蠕变试验获得的蠕变规律较之单轴蠕变试验更能反映实际受力过程中的变形规律，三维的改进Burgers模型能够准确反映热力耦合作用下浇注式沥青混凝土的蠕变特性。

Triaxial Creep Properties of Gussasphalt Concrete under the Thermal Coupling

In order to further research the triaxial creep properties of bituminous mixture of gussasphalt concrete under the effect of temperature and stress coupling , MTS815 testing machine was adopted to carry out triaxial creep test under circumstance of different temperatures , different stress levels and confining pressures , and the corresponding creep curves were obtained , and generalizes the modified Burgers model to three dimensional form in order to describe the creep constitutive relation of gussasphalt concrete .The results show that the first phase of creep curve of gussasphalt concrete is not obvious ,which reflects that the internal void ratio is lower .The creep deformation value sharply increases with the rise of temperature and the increase of deviatoric stress level , which reflects that the combined action of high temperature heavy load is a decisive factor of the rutting on asphalt concrete pavement .The creep deformation slightly decreases with the increase of confining pressure , and the confining pressure has inhibitory effect on creep deformation .The creep rule got from the triaxial creep test , compared with uniaxial creep test , is more able to reflect the deformation law in the process of actual load ,and three-dimensional and modified Burgers model can accurately reflect the creep properties of bituminous mixture of gussasphalt concrete under the effect of temperature and stress coupling .