胶粉复合改性沥青混合料疲劳性能试验研究

Fatigue Performance of Rubber Powder Composite Modified Asphalt Mixture

为提高橡胶沥青混合料的抗疲劳开裂性能,将SBS与胶粉复合进行沥青改性,制备不同配比的胶粉-SBS改性沥青,然后以"干拌"方式掺入玄武岩纤维制备胶粉复合改性沥青混合料,通过四点弯曲疲劳寿命试验全面分析14种沥青混合料的疲劳寿命与劲度模量,对其抗疲劳开裂性能与自愈合能力进行综合评价。结果表明:2%SBS+14%CR沥青胶结料疲劳因子在不同温度下普遍较小,其疲劳性能明显优于其他配比的沥青胶结料;混合料Ⅱ的疲劳寿命最大、Ⅶ其次,且均远大于其他混合料;混合料Ⅶ的疲劳寿命恢复率最大、AR与Ⅱ其次;混合料Ⅶ的劲度模量恢复率最大,Ⅱ其次。因此,在橡胶沥青混合料中掺入适量的SBS改性剂与玄武岩纤维,可以获得较强的疲劳寿命与最强的自愈合补偿能力,其最佳质量配比为m(基质沥青)∶m(胶粉)∶m(SBS)=100∶14∶2与m(矿料)∶m(BF)=1 000∶3。

In order to improve the fatigue performance of asphalt rubber mixture,firstly,different ratio of CR-SBS modified asphalt was produced by compounding asphalt rubber with SBS. Then,powder composite modified asphalt mixture was prepared through mixing with basalt fiber in the form of‘dry mixing',and fatigue test was carried out on it. Fatigue and stiffness modulus of 14 kinds of asphalt mixture were comprehensively analyzed to evaluate the ability of anti-fatigue cracking and self-healing by four-point bending fatigue life test. It was turned out that the asphalt binder,adopting optimal proportion of 14% rubber powder and 2% SBS of matrix asphalt,had significantly better fatigue properties than other proportion of asphalt binder at different temperatures. Fatigue life of mixtures Ⅱ was maximum,Ⅶ next,and both were much larger than the others. Fatigue recovery rates of mixture Ⅶ was maximum,AR andⅡnext. Stiffness modulus recovery rate of mixture Ⅶ was maximum,Ⅱ next. Therefore,mixing right amount of SBS modifier and basalt fiber in rubber asphalt mixture can gain a strong sense of fatigue life and the most powerful self-healing compensation capacity,and the optimal quality proportion is masphalt that m( asphalt) ∶ m( CR) ∶ m( SBS) = 100∶ 14∶ 2与 m( mineral aggregate) ∶ m( BF) = 1 000∶ 3.