基于X-ray CT和离散元法级配离析对沥青混合料骨架结构力学性能的影响

为从细观角度探究分析级配离析对沥青混合料骨架结构力学性能的影响,基于X-ray CT断层图像扫描技术和离散元法建立三维混合料骨架模型,对不同级配离析情况下的混合料骨架内部受力情况、抵抗荷载性能、应力传递性能等方面进行了对比和研究。结果表明:提出了利用X-ray CT断层图像扫描技术构建更接近于真实形态的集料颗粒模型的方法;骨架结构中较粗集料承受了主要的外力荷载作用;以典型的SMA-16级配为例,4.75~9.5 mm档集料是构成该级配集料骨架的关键粒径;骨架结构中细集料的增多有助于提高骨架的抗压强度,发生粗集料离析时,抗压强度将随着离析程度的加剧而显著地降低;不同的级配离析状态对混合料骨架结构的竖向与横向应力传递性能产生不同影响,其中细集料离析对应力传递性能的影响更大。

Influence of Gradation Segregation on Mechanical Properties of Asphalt Mixture Skeleton Structure Based on X-ray CT and Discrete Element Method

A three-dimensional mixture skeleton model is established based on X-ray CT tomographic image scanning technology and discrete element method to explore the influence of gradation segregation on mechanical properties of asphalt mixture skeleton structure from a microscopic perspective.The internal forces,load resistance and stress transfer performance of the mixture skeleton under different gradation segregation conditions are compared and studied.A method of constructing aggregate particle model which is closer to the real shape by X-ray CT tomographic image scanning technology is proposed.The coarse aggregate in skeleton structure bears the main external load.Taking typical SMA-16 gradation as an example,4.75 mm^9.5 mm grade aggregate is the key particle size of aggregate skeleton.The increase of fine aggregate in the skeletal structure helps to improve the compressive strength of the skeleton.The compressive strength decreases significantly with the increase of segregation degree when coarse aggregate segregation occurs.Different gradation segregation states have different effects on the vertical and lateral stress transmission performance of the skeletal structure.The fine aggregate segregation has greater influence on the stress transfer performance.