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为了研究复合纤维沥青混合料在高温持续荷载作用下的稳定性,根据工程中常用纤维和已有研究成果,选用了三种复合纤维,对沥青混合料的变形发展规律及内部空隙结构特征开展试验研究。首先采用加速加载试验,对不掺加纤维和掺加复合纤维的沥青混合料在高温持续荷载作用下的横断面变化和车辙深度进行分析;再利用X-CT扫描技术与VG软件三维重构功能,研究不同纤维沥青混合料的空隙组成及形态特征演变规律。结果表明:高温持续荷载作用下,掺加纤维混合料横断面变形呈现“W”字型,不同纤维在沥青混合料中发挥“加筋”、“增黏”、“吸油”的协同作用,能显著减小沥青混合料的流动变形,且掺加复合纤维III的混合料流动变形最小;掺加不同复合纤维的沥青混合料可采用y=a-b·ln(x+c)进行车辙深度预估。加速加载试验后,掺加三种复合纤维的沥青混合料空隙率最大仅增加7%,分形维数仅降低不到0.5%,表明掺加三种复合纤维基本不改变沥青混合料的空隙结构特征,而且在高温持续荷载作用下,可较好地保持沥青混合料内部空隙的三维形态特征,进而改善沥青混合料的抗变形能力。
In order to study the stability of composite fiber asphalt mixture under continuous loading under high temperature, three kinds of composite fibers were selected according to the commonly used fibers in engineering and the existing research results. The deformation and development of asphalt mixture and the structural characteristics of internal voids were tested the study. Firstly, the cross-sectional changes and the depth of rutting of the asphalt mixture without or with fiber-added composite fiber under continuous loading under high temperature were analyzed by accelerated loading test. By using X-CT scanning technology and 3D reconstruction function of VG software , To study the void composition and morphological evolution of different fiber asphalt mixtures. The results show that the cross - section deformation of the blended fiber mixture shows the shape of “W” under continuous loading under high temperature. Different fibers play the role of “reinforcement”, “thickening”, “ Oil absorption ”synergistic effect, can significantly reduce the flow deformation of asphalt mixture, and mixed with composite fiber III mixture flow distortion minimum; mixed with different fiber composite asphalt mixture can be used y = ab · ln (x + c) Rut depth estimation. After accelerated loading test, the asphalt mixture with three kinds of composite fibers only increased the porosity by only 7% and the fractal dimension by only less than 0.5%, indicating that the incorporation of the three kinds of composite fibers basically did not change the void structure characteristics of the asphalt mixture , But also maintain the three-dimensional morphological characteristics of the internal voids of the asphalt mixture well under high temperature sustained load, thereby improving the anti-deformation ability of the asphalt mixture.