高寒高海拔地区玄武岩纤维沥青混凝土损伤自愈合性能分析

为探究玄武岩纤维沥青混凝土在不同损伤程度及冻融循环、紫外辐射老化作用下的损伤自愈合性能,利用四点弯曲疲劳试验及扫描电子显微镜从宏、微观角度进行分析。通过对比分析试件愈合前后疲劳损伤速率v_D及累计耗散能ECD分别得到相应的愈合系数R_HI,结果表明:玄武岩纤维能提高普通基质沥青混凝土的损伤自愈合性能,其损伤愈合系数最大值为96％;在相同环境因素中,试件的损伤程度与愈合系数成反比;在相同的损伤程度下,冻融循环对试件的愈合性能影响最大,损伤愈合系数下降幅度最高达到4％;利用累计耗散能作为评价指标,可以更精确地表征沥青混凝土的损害自愈合性能。通过扫描电镜图像分析,从微观上解释了玄武岩纤维对于沥青混凝土紫外辐射老化及冻融作用前后自愈合性能的影响机理。

Analysis of Damage Self-Healing Performance of Basalt Fiber Asphalt Concrete at High-Cold and High-Altitude Area

In order to explore the self-healing properties of basalt fiber asphalt concrete under different damage levels, freeze-thaw cycles, and ultraviolet radiation aging, afour-point bending fatigue test and scanning electron microscope were used to analyzefrom macro and micro angles.By comparing and analyzing the fatigue damage rate v_D and the cumulative dissipated energy E_CD before and after the specimen healing, the corresponding healing coefficient R_HI was obtained respectively. The conclusion shows that basalt fiber has improved damage self-healing properties of ordinary matrix asphalt concrete, and the maximum value of the damage healing coefficient is 96%. Under the same environmental factors, the damage degree of the test piece is inversely proportional to the healing coefficient. At the same degree of damage, the freeze-thaw cycle has the greatest impact on the healing performance of the test piece, and the damage healing coefficient decreases by up to 4%. Cumulative dissipated energy can be used as an analysis index to more accurately characterize the damage self-healing performance of asphalt concrete.Through scanning electron microscopy image analysis, the mechanism of the effect of basalt fiber on the self-healing performance of asphalt concrete before and after ultraviolet and freeze-thaw action was further microscopically explained.