橡胶沥青混合料疲劳性能的自愈合影响因素分析

Analysis of Influencing Factors for Self-healing of Fatigue Performance of Asphalt Rubber Mixture

通过室内四点弯曲疲劳试验,选取ASTM D7460的NfNM疲劳判断标准,采用单因素对比分析的方法,对橡胶沥青混合料疲劳性能的自愈合能力的主要影响因素(沥青用量、试件破坏程度、胶粉掺量、空隙率、应变量大小、自愈合时间、自愈合温度以及荷载强度)进行了系统研究,并对考虑自愈合补偿后的橡胶沥青混合料的疲劳行为方程进行了回归拟合。结果表明:疲劳自愈合效率与沥青用量、自愈合时间成正比,与试件破坏程度、空隙率、应变量大小成反比,在胶粉掺量(胶粉与橡胶沥青的质量比)为20%,自愈合温度为60℃,荷载强度为5kPa时,疲劳自愈合效率分别达到最佳;考虑自愈合补偿的疲劳次数与应变量大小、沥青用量和空隙率存在很好的相关性。

NfNM method of ASTM D7460 was chosen as asphalt mixture＇s fatigue failure criterion,and single factor comparative analysis and indoor four-point bending fatigue test were used to fulfill a systematic study on the main factors which affect the self-healing capacity of fatigue performance of asphalt rubber mixture.These factors were the amount of asphalt,damage,crumb rubber content,void ratio of mixture,strain,self-healing time,self-healing temperature and load.The fatigue behavior equation of asphalt rubber mixture with self-healing compensation considered was regressed out.The results show that the fatigue self-healing efficiency is proportional to the amount of asphalt and self-healing time,inversely proportional to the extent of the damage,void ratio of mixture and strain,and when the crumb rubber content is 20%,self-healing temperature is 60 ℃,and load is 5 kPa,fatigue self-healing efficiency achieves optimum results;there is a good correlation between the amount of asphalt and void ratio of mixture with self-healing compensation and strain considered.