沥青混合料高温性能试验方法

基于局部加载的思想设计了一种新的试验方法(局部三轴试验)来正确模拟路面实际状态,并获得准确的沥青混合料永久变形计算参数。通过ABAQUS有限元计算出试件、压头和底座的合理尺寸;利用该试验方法和常规三轴试验对AC20和SMA13沥青混合料进行了重复荷载蠕变试验,基于不同试验结果回归的参数对车辙试验建模计算,并与实测车辙对比分析。结果发现,局部三轴和传统三轴试验结果的规律性一致,流动次数FN均随温度和应力的增大而减小,且沥青混合料在高温或重载下均表现出较大的变形速率。但与车辙试验实测车辙量及永久变形率相比,由传统三轴试验所得参数计算出的结果偏小,而局部三轴试验所得参数计算出的车辙量及永久变形率与实测值较为一致;且从试验设备要求、试件制备过程和试验操作等方面分析,局部三轴试验更加简单易行。

A Test Design for High-temperature Performance of Asphalt Mixtures

In order to correctly simulate the real condition of asphalt pavement and obtain accurate parameters for permanent deformation calculation,a new test(partial triaxial test,PTT) was devised based on the idea of loading on partial area.Rational dimensions of specimen and platens were calculated by ABAQUS finite element method.Then repeated-load creep tests were carried out on AC20 and SMA13 asphalt mixtures using PTT and traditional triaxial test.Creep parameters regressed from the two tests' results were respectively employed to calculate rutting tests' permanent deformation,which were then compared with measured values.Results indicate that,both PTT and traditional triaxial test represent the same deformation characteristics of asphalt mixtures,i.e.,flow number(FN) decreases with the increase of temperature and load,and the deformation of asphalt mixtures increase more quickly at a high temperature or a heavy load;the rut depths and deformation slope calculated using the parameters of traditional triaxial tests are obviously smaller than the measured results which are reasonably consistent with calculated rut depths and deformation slope with the parameters of PTT.In addition,PTT is easier to carry out than traditional triaxial test considering simplicity of experiment equipments,specimen preparation and tests operation.