改性沥青应力吸收层混合料低温抗裂性能评价

Evaluation of Anti-cracking Performance of Modified HMA in Stress Absorbing Layers Under Low Temperature

为了评价应力吸收层复合改性沥青混合料的低温抗裂性能,设计试验夹具和制作试件,确定试验参数并进行圆盘拉伸破坏试验,采用拉伸劲度、拉伸破坏强度、断裂能评价其低温抗裂性,分析矿料级配、试验温度、沥青结合料类型、油石比对混合料低温抗裂性能的影响。结果表明:断裂能是评价应力吸收层混合料低温抗裂性能的综合指标,矿料级配对其抗裂性能影响较敏感,贴近级配中值混合料抗裂性能并非最优;低温抗裂试验比较合理的温度为0℃;普通SBS改性沥青难以满足应力吸收层混合料低温抗裂性要求。

In order to evaluate the low temperature： anti-cracking performance of mixture with compound modified asphalt at stress absorbing layers, test fixture and specimens were designed, test parameters were determined and disk-shaped tension experiment was carried out, and then the low temperature anti-cracking performance was evaluated by tensile stiffness, tensile failure strength and fracture energy. Furthermore, the influence of aggregate gradation, test temperature, asphalt binder and asphalt aggregate ratio on low temperature anti-cracking performance was analyzed. The results indicate tha~ the fracture energy is the comprehensive index to evaluate low temperature anti-cracking performance, aggregate gradation sensitively affects anti-cracking performance, the mixture with gradation close to median limit is not the best and the rational test temperature to evaluate low temperature anti-cracking performance is 0 ℃ the low performance of common SBS modified asphalt can not meet the demand of stress absorbing layers under low temperature.