基于多尺度的冻融循环及荷载作用下钢渣沥青混合料开裂机理研究

钢渣是钢铁工业产生量最大的固体废物之一，将其进行陈化处理用于沥青路面对于废物循环利用、保护环境及提高路面质量具有重要意义。本项目针对冻融循环及荷载作用下钢渣沥青混合料损伤、开裂问题，基于物理化学分析、宏细观力学原理及分子动力学模拟技术，通过X射线衍射及荧光光谱实验研究钢渣及沥青-钢渣界面物相及化学组成特性；通过扫描电子显微镜研究其细观结构特性及变化规律；通过数字图像相关方法分析宏、细观尺度下钢渣沥青混合料损伤、断裂全过程全场应变分布规律，并基于应变、应力变化描述钢渣沥青混合料损伤程度；利用分子动力学模拟研究钢渣沥青混合料损伤、劣化发展规律；基于多尺度角度，建立钢渣沥青混合料细观损伤与宏观性能劣化间的相关关系，研究冻融循环及荷载作用下钢渣沥青混合料性能衰减特征，揭示钢渣沥青混合料粘结损伤、开裂机理。该项目既有地区特点，同时对于深入了解钢渣沥青混合料宏细观力学行为和多尺度研究方法具有重要意义。

Steel slag is one of the largest solid wastes produced by steel industry. It is important to be used in asphalt pavement to waste recycling, environmental protection and road quality improvement after aging. This project is aimed at the damage and cracking of steel slag asphalt mixture under freeze-thaw cycle and load. Based on physical and chemical analysis, macroscopic and microscopic mechanics theory and molecular dynamics simulation technology, the phase and chemical composition of the steel slag and asphalt-steel slag inteface are studied by X-ray diffraction and X-ray fluorescence spectroscopy. The microstructural characteristics and variation law are studied by scanning electron microscopy. The digital image correlation method is used to measure the whole field strain distribution of the steel slag asphalt mixture in damage and fracture process under the macro and microscale, and the damage degree of steel slag asphalt mixture is described based on strain and stress change; The damage and deterioration of steel slag asphalt mixture is studied by molecular dynamics simulation; The correlation between microscopic damage and macroscopic performance degradation of steel slag asphalt mixture is established based on multi-scale.The performance degradation characteristics of steel slag asphalt mixture under freeze-thaw cycles and loads are studied, and the bond damage and cracking mechanism of steel slag asphalt mixture were revealed. The project has both regional characteristics and important significance to further understand the macro, micro-mechanical behavior and multi-scale research methods of steel slag asphalt mixture.