不同尺寸玄武岩纤维混掺沥青混合料抗裂性能研究

Research on Crack Resistance of Asphalt Mixtures Mixed with Basalt Fibers of Different Sizes

针对常规沥青路面材料开裂问题,提出通过不同长度的玄武岩纤维混掺来改善沥青混合料的抗裂性能.选取-10℃、-20℃、-30℃低温开裂温度及15℃、25℃疲劳开裂温度,通过低温小梁弯曲试验和SCB半圆弯拉试验测试抗裂效果,SEM扫描电镜分析断裂面微观形貌,研究7种不同长度玄武岩纤维混掺方案下沥青混合料的抗裂性能.结果表明:纤维混掺有利于延缓开裂速度,增强低温抗裂性.在半圆弯拉试验中观察到裂缝首先出现在峰值荷载的80%处,并在卸载阶段迅速扩大.混掺比例为3∶2时表现出最佳综合抗裂效果,较无纤维沥青混合料及单掺纤维沥青混合料的抗裂效果提升显著.

Aiming at the cracking problem of conventional asphalt pavement materials,it is proposed to improve the cracking resistance of asphalt mixture by mixing basalt fibers with different lengths.The low-temperature cracking temperatures of-10℃,-20℃and-30℃and the fatigue cracking temperatures of 15℃and 25℃were selected,and the anti-cracking effect was tested by low-temperature trabecular bending test and SCB semi-circular bending test.The micro-morphology of fracture surface was analyzed by SEM,and the crack resistance of asphalt mixture under seven different basalt fiber mixing schemes was studied.The results show that fiber blending is beneficial to delay the cracking speed and enhance the low temperature cracking resistance.In the semi-circular bending-tension test,it was observed that the crack first appeared at about 80%of the peak load,and expanded rapidly in the unloading stage.When the mixing ratio is 3∶2,it shows the best comprehensive anti-cracking effect,which is significantly higher than that of fiber-free asphalt mixture and fiber-only asphalt mixture.