Study on the Low Temperature Cracking Mechanism of Steel Slag Asphalt Mixture by Macroscale and Microscale Tests
Study on the Low Temperature Cracking Mechanism of Steel Slag Asphalt Mixture by Macroscale and Microscale Tests
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DOI：
10.1155/2022/4875276
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发表时间：
2022-12
影响因子：
--
通讯作者：
Lan Wang;Xuefeng Bai
中科院分区：
文献类型：
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作者：
Lan Wang;Xuefeng Bai
钢渣的物理机械性能接近天然碎石，可替代天然骨料铺筑沥青混合料路面。有必要从宏观和微观尺度研究钢渣沥青混合料（SAM）的低温开裂特性。本文旨在通过宏观和微观试验研究钢渣沥青混合料的低温开裂特性及其影响机制。本文通过三点弯曲试验结合数字图像相关（DIC）分析了SAM在低温下的应变场分布和裂纹扩展规律。通过核磁共振（NMR）研究了SAM的微观孔隙特征。基于断裂力学和权重函数理论，推导了沥青混合料裂纹尖端应力强度因子随裂纹扩展的变化规律。基于灰色关联理论分析沥青混合料微观孔隙与低温开裂特性的相关性。结果表明，SAM的小孔隙较多，大孔隙较少，其总孔隙率小于玄武岩沥青混合料（BAM）。 SAM抵抗弯曲变形的初始弹性阶段比BAM长，弯曲应变能密度(dW/dV)较大，裂纹穿透较慢。 SAM的水平应变能密度（DE）大于BAM，裂纹尖端应力更大。孔隙率与沥青混合料的低温抗裂性密切相关。
Steel slag’s physical and mechanical properties are close to natural gravel, which can replace natural aggregate with paving asphalt mixture pavement. Based on macro- and microscales, it is necessary to study the low-temperature cracking characteristics of steel slag asphalt mixture (SAM). This paper aims to study the low-temperature cracking characteristics and influence mechanism of steel slag asphalt mixture by macro- and microscale tests. This article analyzes the strain field distribution and cracks propagation law of SAM at low temperatures by the three-point bending test combined with digital image correlation (DIC). The microscopic pore characteristics of SAM were studied by nuclear magnetic resonance (NMR). Based on fracture mechanics and weight function theory, the variation law of the stress intensity factor at the crack tip of the asphalt mixture with crack propagation is derived. The correlation between microscopic pores and low-temperature cracking characteristics of asphalt mixture was analyzed based on the grey correlation theory. The results show that SAM has more small and less large pores, and its total porosity is lesser than that of the basalt asphalt mixture (BAM). The initial elastic stage of SAM resisting bending deformation is longer than that of BAM, the bending strain energy density (dW/dV) is larger, and the crack penetration is slower. The horizontal strain energy density (DE) of SAM is greater than BAM, and the crack tip stress is greater. The porosity correlates well with the low-temperature crack resistance of the asphalt mixture.