不同沥青基材料砂浆抗剪力学性能分析

Study on the Shear Performance of Various Asphalt Matrix Material Mortar

为了量化分析沥青混合料中不同沥青基材料砂浆抗剪力学性能的优劣,使其结果作为判断沥青砂浆影响混合料路用性能的依据,以剪切试验为基础,分析了常规条件与冻融条件下,橡胶沥青砂浆、70#沥青砂浆及其加入外掺剂砂浆的应力响应规律,提出了定量分析砂浆抗剪性能的指标,对4种砂浆的抗剪力学性能进行了对比分析。研究结果表明:常规条件下,70#沥青砂浆的黏聚强度c与内摩擦角φ分别为橡胶沥青砂浆的77%和76%,加入外掺剂橡胶沥青砂浆的黏聚强度c与内摩擦角φ分别为未加外掺剂橡胶沥青砂浆的1.41倍和1.29倍,由此可知,使用橡胶沥青与加入外掺剂,不仅能够提高砂浆的强度,而且可以改善砂浆的抗剪力学性能;冻融条件下,70#沥青砂浆的黏聚强度c与内摩擦角φ分别为橡胶沥青砂浆的64%和61%,加入外掺剂70#沥青砂浆的黏聚强度c与内摩擦角φ分别为未加外掺剂70#沥青砂浆的1.18倍和1.46倍,由此可知,使用橡胶沥青与加入外掺剂能够改善砂浆的水稳定性,减少冻融损伤,确保冻融后砂浆的抗剪切力学性能。

In order to determine the impact of the shear property of asphalt mortar on the performance of asphalt mixture, this paper conducted a quantitative study on the shear properties of various asphalt mortar. Based on shear tests, the stress responses of four different mortar materials, including the 70 # asphalt mortar with and without mixing additives and the rubber asphalt mortar with and without mixing additives, were analyzed under normal conditions and freeze-thaw conditions respectively. Then, a shear property index was proposed to quantify and compare the shear performance of these four mortar materials. The results indicated that the cohesion strength and the internal friction angle of the 70# asphalt mortar were 77% and 76% of corresponding values of the rubber asphalt mortar respectively, while the cohesion strength and the internal friction angle of the rubber asphalt mortar with additives were 1.41 times and 1.29 times greater than those of the rubber asphalt mortar without additives respectively. There fore, the adoption of rubber asphalt and additives can improve not only the strength, but also the shear performance of asphalt mortar under normal conditions. On the other hand, under freeze-thaw conditions, the cohesion strength and the internal friction angle of the 70#asphalt mortar were 64 % and 61% of corresponding values of the rubber asphalt mortar respectively, while the cohesion strength and the internal friction angle of the 70# asphalt mortar with additives were 1.18 times and 1.46 times greater than those of the 70# asphalt mortar without additives respectively. Therefore, the adoption of rubber asphalt and additives both are able to improve the water stability of the mortar, reduce the freeze-thaw damage, and ensure the shear property of the asphalt mortar after freeze-thaw action.