沥青稳定基层混合料疲劳性能试验研究

Experimental Research on Fatigue Performance of Asphalt-treated Base Mixtures

对5种级配的沥青稳定基层混合料进行了控制应变的三分点小梁弯曲疲劳试验,分析了级配、沥青用量、沥青品种和温度对沥青稳定基层疲劳性能的影响规律。研究表明:悬浮密实型沥青混合料的疲劳性能较嵌挤型沥青混合料好得多;沥青用量增加,疲劳寿命显著增长,由马歇尔方法确定的最佳沥青用量并非沥青混合料疲劳性能最佳的沥青用量;沥青混合料疲劳寿命随试验温度的提高而显著增长;采用改性沥青的沥青混合料疲劳性能较普通沥青有一定改善。这些规律可以为沥青稳定基层的混合料设计提供参考。

Flexible base asphalt pavements have been used widely in high grade roads in China.The fatigue performance is one of the most important properties for asphalt-treated base mixtures. Firstly, five kinds of asphalt mixtures were tested with the third-point flexure fatigue test under strain controlled mode with the effects of aggregate gradation, asphalt content, asphalt property and test temperature on fatigue performance of asphalt-treated base analyzed, which can be considered in asphalt-treated base mixtures design.The result shows that the fatigue performance of framework-dense mixtures is better than suspend-dense mixtures. Fatigue life is improved markedly by the increase of bitumen content and the optimal asphalt content （OAC） determined by Marshall method is less than the OAC with best fatigue performance. Fatigue life of asphalt mixture in higher temperature is longer than that in lower temperature. The asphalt mixture with modified asphalt.is better than ordinary asphalt mixture in terms of fatigue performance.