硬质沥青混合料低温性能试验研究

Experimental research on low temperature performance of hard asphalt mixture

为了研究硬质沥青的感温性与沥青混合料的低温抗裂性能的关系,选取4种不同品牌和标号的硬质沥青,对其感温性指标进行了试验。对使用4种沥青的沥青混合料成型小梁试件,进行低温弯曲试验,得到了不同温度下4种沥青混合料的抗弯极限强度、抗弯拉应变以及弯曲劲度模量参数。同时利用Hills低温开裂预估温度方程建立沥青混合料低温抗裂性能评估模型,对4种硬质沥青混合料的低温抗裂性能进行评估。结果表明:沥青的感温性及15℃延度值与沥青混合料的低温抗裂性能有着很好的相关性,沥青路面存在1个温度应力起始温度t0,沥青不同,路面t0不同。当路面温度高于t0时,路面内部不产生温度应力,随着温度的降低,温度应力出现且增幅变大,当温度应力大于路面的极限强度时,路面就会存在开裂的风险。

In order to study the relationship between the temperature sensitivity of hard asphalt and the low temperature anticracking performance of asphalt mixture, four hard asphalts of different brands and labels were selected to test their temperature sensitivity indexes. Low-temperature bending tests were carried out on specimens of trabeculae formed with four asphalt mixtures, and the flexural ultimate strength, flexural tensile strain and bending stiffness modulus parameters of the four asphalt mixtures at different temperatures were obtained. At the same time, the Hills low-temperature cracking predictive temperature equation was used to establish an asphalt mixture low-temperature anti-cracking performance evaluation model, and the lowtemperature anti-cracking performance of four hard asphalt mixtures was evaluated. The results show that the temperature sensitivity and 15 ℃ ductility of asphalt have a good correlation with the low-temperature anti-cracking performance of asphalt mixtures. Asphalt pavement has a temperature stress starting temperature t0, which differs from asphalt and pavement t0. When the pavement temperature is higher than t0, no temperature stress is generated inside the pavement. As the temperature decreases, the temperature stress appears and increases. When the temperature stress is greater than the ultimate strength of the pavement, the pavement will be at risk of cracking.