沥青混合料疲劳自愈合特性研究

沥青混合料具有疲劳自愈特性.通过室内四点弯曲疲劳试验,采用“疲劳-愈合-再疲劳”的试验方式和单因素对比分析的方法,探究了养护时间、温度、集料级配及沥青胶结料种类对沥青混合料的自愈合特性的影响,并建立愈合指标函数.结果表明：沥青混合料自愈合效果呈时间依赖性,即随养护时间的增加,自愈合效果增强,且初期愈合速度较快;在一定温度范围内,随温度提高,沥青混合料自愈合效果增强;70#基质沥青混合料的短期自愈合能力优于SBS改性沥青混合料;PA-13型沥青混合料自愈合能力优于AC-13型沥青混合料.同时,从混合料组成特点及沥青微观结构等方面剖析了各因素影响机理.

Investigation of Fatigue and Self-healing Characteristics of Asphalt Mixtures

Asphalt mixtures exhibited a fatigue and healing capability. This study conducted indoor four-point bending fatigue experiments through the ＂fatigue-healing-re-fatigue＂ test mode and single factor comparative analysis, exploring how the curing time, temperature, aggregate gradation and asphalt binder type influence on the self-healing property of asphalt mixture. By establishing a corresponding healing index function, the results showed that： the self-healing effect of asphalt mixture was time- dependent, which increased with the curing time and faster in early stage. In a certain temperature range, the self-healing effect of asphalt mixture increased with temperature. The short-term self-healing capability of base asphalt mixture was superior to modified asphalt mixture. The self-healing capability of PA-13 asphalt mixture was superior to AC-13 asphalt mixture. Meanwhile, various factors affecting mechanism were analyzed from the composition of mixture and microstructure of asphalt.