掺加纤维对高模量沥青混合料柔韧性及路用性能影响研究

为了评价单纤维及交织化复合纤维对BRA改性高模量沥青混合料性能的增强作用,并揭示纤维对高模量沥青混合料的增柔增韧改性机理。采用半圆针入度试验、直接拉伸试验和直接剪切试验研究了纤维对高模量沥青柔韧性和剪切性能的影响,通过电子显微镜(SEM)分析了纤维BRA高模量沥青的表面形貌特征,并采用车辙试验、贯入剪切试验、低温弯曲试验、冻融劈裂、浸水马歇尔试验、间接拉伸疲劳试验和MMLS1/3加速加载试验评价了纤维高模量沥青混合料的各项性能。结果表明,掺加单纤维及交织化复合纤维能显著提高BRA高模量沥青的蠕变柔量和抗剪切强度;纤维的微观形貌差异决定了不同纤维原材料对高模量沥青及其混合料性能改善效果有一定侧重点,采用交织化纤维复配方案恰好实现了不同纤维对BRA改性沥青性能改善效果的叠加作用;m(木质素纤维)∶m(聚酯纤维)∶m(玄武岩纤维)=1∶2∶2组成的交织化纤维,其对高模量沥青混合料各项路用性能有较大提升并且更加均衡,改性效果更佳明显;交织化纤维方案对改善高模量沥青混合料低温抗裂性能、长期高温稳定性和抗疲劳耐久性方面有较好技术优越性。

Study on the influence of fiber on flexibility and road performance of high modulus asphalt mixture

In order to evaluate the reinforcing effect of single fiber and composite fiber on the performance of BRA modified high modulus asphalt mixture, the mechanism of fiber softening and toughening modification of high modulus asphalt mixture was revealed. The effects of fiber on the flexibility and shear properties of high modulus asphalt were studied by semi-circular penetration test, direct tensile test and direct shear test. The surface shape of fiber BRA high modulus asphalt was analyzed by electron microscopy (SEM). The rutting test, penetration shear test, low temperature bending test, freeze-thaw splitting, water-immersed Marshall test, indirect tensile fatigue test and MMLS1/3 accelerated loading test were used to evaluate the fiber high modulus asphalt mixture. The results show that the addition of single fiber and interwoven composite fiber could significantly improve the creep compliance and shear strength of BRA high modulus asphalt. The difference in fiber morphology determined the high modulus asphalt and its mixing. The material performance improvement effect had a certain focus. The interwoven fiber blending scheme just achieved the superposition effect of different fibers on the performance improvement of BRA modified asphalt. The interwoven fiber with m (lignin fiber)∶ m polyester fiber)∶ m (basalt fiber)=1∶2∶2 had higher performance and more balanced performance for high modulus asphalt mixture, and the modification effect was better and obvious. The interwoven fiber solution improved the low temperature crack resistance of the high modulus asphalt mixture. It had good technical superiority in long-term high temperature stability and fatigue durability.