沥青混合料高温稳定性影响因素试验分析

设计了不同级配类型的沥青混合料,通过车辙试验和单轴静载蠕变试验,研究了交通荷载、环境温度、材料类型和水作用（高温浸水和冻融循环）对沥青混合料高温稳定性能的影响.试验结果表明,荷载和环境温度对沥青混合料的高温稳定性具有明显的影响.由于沥青混合料的粘性,随着荷载的增加和温度的升高,沥青混合料的动稳定度呈幂指数关系减小.中间级配（玄AC13-2、石AC20-5）的沥青混合料高温稳定性较好;细级配的沥青混合料高温稳定性最差;大粒径沥青混合料高温稳定性能优于小粒径沥青混合料.水的作用严重削弱了沥青混合料高温稳定性能,而冻融循环的影响要远远大于高温浸水.并且Burgers模型可用于表征沥青混合料水损害前后蠕变性能,且其粘弹性参数均受到水作用的不同程度影响,水作用对沥青混合料抗高温变形能力极为不利.

Experimental analysis of influence factors on high temperature stability of asphalt mixture

Different types of asphalt mixture with different gradation are designed. The effects of load, temperature, material type and water intrusion （hot water immersion and freeze-thaw cycle） on high temperature stability of asphalt mixture are studied by rutting test and static creep test under single axle compressing. Test results show that load and temperature influence high temperature stability of asphalt mixture seriously. Due to the viscosity of asphalt mixture, with the increase in load and temperature, the dynamic stabili- ty of asphalt mixture is reduced with exponential relationship. The asphalt mixtures with middle gradation （Basalt AC13-2, Limestone AC20-5） has better high temperature stabili- ty, but the fine graded asphalt mixtures is the worst; accordingly asphalt mixtures with large size aggregate is better than those with small size aggregate. The effect of water seri- ously weakens the high temperature stability of asphalt mixture, and the impact of the freeze-thaw cycle is much stronger than the hot water immersion. Besides, Burgers model can be used to characterize the creep performance of the asphalt mixture before and after waterdamage, and the viscoelastic parameters are influenced by water intrusion. The water intrusion is extremely unfavorable to anti-high-temperature deformation capacity of asphalt mixture.