微胶囊对沥青混合料疲劳与自愈性能影响研究

Effect of Microcapsules on the Fatigue and Self-Healing Performance of Asphalt Mixture

微胶囊在增强沥青自愈合性能、延长沥青路面使用寿命方面具有非常大的潜力。首先,利用红外光谱定量分析方法,评价了微胶囊在沥青混合料中的存活率。然后,利用沥青黏结强度试验对含有微胶囊的沥青进行拉拔测试,借助荧光显微镜观测拉拔断面中微胶囊的激活行为。在此基础上,利用四点弯曲疲劳试验研究微胶囊对沥青混合料疲劳与自愈合性能的影响。研究结果表明,微胶囊在温拌沥青混合料的存活率可达69.87%,比在热拌沥青混合料中高9.64%。在常温条件下,微胶囊可以被沥青中的裂缝激活并释放再生剂。微胶囊对沥青混合料的初始抗疲劳性能有显著增强作用,主要因为微胶囊在施工期间和加载过程中释放出的再生剂软化了沥青,降低了沥青混合料试件的内部应力并极大程度上加速裂纹愈合。适量的微胶囊能够显著增强沥青混合料的自愈合性能,而且随着“疲劳-愈合”次数的增加,微胶囊对沥青混合料自愈合性能增强作用逐渐凸显。

Microcapsules containing healing agents have great potential in enhancing the self-healing performance of asphalt and prolonging the service life of asphalt pavement.Firstly,the survival rate of microcapsules in asphalt mixture is evaluated by Infrared Spectrum Quantitative Analysis method.Then,the asphalt binder with microcapsules is pulled by the Bitumen Bond Strength(BBS) test,and the activation behavior of microcapsules in the fracture surface is observed by fluorescence microscope(FM).On this basis,the FourPoint Bending Fatigue test is applied to study the effects of microcapsules on the fatigue and self-healing performance of asphalt mixture.The results showed that the survival rate of microcapsules in warm mix asphalt mixture is 69.87%,which is 9.64% higher than that in hot mix asphalt mixture.At room temperature,microcapsules are activated by cracks in asphalt and release regenerant.The microcapsules significantly enhance the initial anti-fatigue performance of asphalt mixture,mainly because the released regenerant during the construction and loading of the microcapsules softened the asphalt,which reduce the internal stress of the asphalt mixture specimen and accelerate the crack healing.An appropriate content of microcapsules significantly enhance the self-healing performance of asphalt mixture.As the numbers of fatigue-healing cycles increased,the enhancement effect of microcapsules on the self-healing performance of asphalt mixture gradually became prominent.