单轴贯入重复剪切试验研究沥青混合料永久变形

Research on Asphalt Mixture Permanent Deformation by Single Penetration Repeated Shear Test (SPRST)

摘要:

沥青路面车辙变形越发严重，降低路面使用寿命的同时大大影响行车安全。通过对比分析，提出运用单轴贯入重复剪切试验研究沥青混合料的永久变形。对高速公路沥青路面上中面层最常用的四种沥青混合料进行了不同荷载水平下的单轴贯入重复剪切试验，得到如下结论：（1）单轴贯入重复剪切试验可以做出沥青混合料的三阶段变形；（2）荷载越大混合料永久变形的速率越大，剪切疲劳寿命或流动数越小。当荷载大于或等于1.3MPa时改性沥青混合料在较小的荷载次数内变形过大，发生剪切破坏。而当荷载小于或等于1.1MPa时变形增加极慢，稳定的处于变形的第二阶段而不破坏；（3）抗剪强度较大的沥青混合料抵抗剪切变形的能力较强，改性沥青混合料抵抗剪切变形的能力远大于普通沥青混合料；（4）荷载应力水平和作用次数具有等效性。

Abstract:

The problem of pavement rutting is getting worse, which reduces pavements’ life and greatly effects driving safety. Through comparative analysis, a single penetration repeated shear test (SPRST) for a research on asphalt mixture permanent deformation was put forward. Many SPRST tests on different load levels were did with four kinds of most commonly used asphalt mixtures in the upper and middle layer of asphalt pavements. Some conclusions were the followings. (1) The three-stage permanent deformation behavior of asphalt mixtures on loads could be got by SPSFT. (2) The bigger the load was the faster permanent deformation of asphalt mixtures increased and the smaller the shear fatigue life or the flow number were. Large load (≥1.3MPa) made the large deformation with not large load cycles and the mixture broke; but the smaller load (≤1.1MPa) got very slow increase of the deformation, which was stably in the second stage of three-stage permanent deformation and didn’t broke. (3) The asphalt mixtures with bigger shear strength had a greater ability resistance to shear deformation. Mixtures with modified asphalt had a greater ability resistance to shear deformation than with conventional asphalt. (4) Load stress levels had an equivalence to load cycles.