硅藻土与纤维复合添加剂对高比例RAP掺量热再生混合料耐久性能的增强作用

Enhancement of Fiber and Diatomite Composite Modified Additive on Durability of Hot Recycled Mixture with High RAP Content

依托“特殊气候条件高RAP掺量热再生混合料耐久性研究”项目,基于室内路用性能试验、APA、MMLS1/3、四点弯曲试验系统研究了纤维硅藻土热再生混合料的长期使用性能。研究结果表明,掺加纤维可显著改善热再生混合料的低温抗裂性能和抗疲劳性能,以硅藻土为原材料的纤维硅藻土复合改性剂能够提高热再生混合料的冻融劈裂试验强度比,减小混合料受到冻融循环水损害之后劈裂抗拉强度的降低幅度。在水-高温-荷载耦合作用下的综合路用性能排序依次是：玄武岩纤维＋13% 硅藻土〉SBS热拌沥青混合料〉聚酯纤维＋13% 硅藻土〉木质素纤维＋13% 硅藻土〉SBS热再生混合料,纤维硅藻土复合改性热再生混合料在水-高温-荷载耦合作用下有更强的适用能力。确定了最佳的纤维和硅藻土掺配比例为0.35% 纤维＋13% 硅藻土,建议在高温高湿环境优先选用0.35% 玄武岩纤维＋13% 硅藻土复合改性方案来改善高RAP掺量热再生混合料的抗车辙和水损害性能。

Relying on special climatic conditions of high RAP content on durability of hot recycled mixtures project, and based on performance test, APA, MMLS1/3, and four-point bending test system, the fiber mixture diatomite thermal regeneration is studied. The results show that adding fiber can significantly improve the thermal regeneration mix low temperature crack resistance and fatigue resistance, diatomite raw materials for fiber composite modifier can improve the thermal regeneration mixture of freeze-thaw splitting test intensity ratio, and reduce the mixture by freeze-thaw cycle after water damage splitting tensile Strength of a reduction. The order of road performance under water - high temperature - Integrated Road Loads coupling actions is. basalt fiber ＋ 13% diatomaceous earth 〉 SBS hot mix asphalt Polyester ＋ 13% diatomite〉 lignin fiber ＋ 13% diatomaceous earth 〉 SBS hot recycled mixtures, and the fiber composite diatomite modified hot recycled mixtures have stronger applicability under water - high temperature - load coupling effect. The optimum fiber and diatomaceous earth doped fiber is at a ratio of 0.35% ＋ 13% of diatomaceous earth, and under hot and humid environment 0.35% ＋ 13% of diatomaceous earth basalt fiber composite modification programs is recommended to improve the high-RAP volume hot recycled mixtures rutting and water damage performance.