再生集料沥青混凝土界面损伤行为特征

水泥混凝土再生集料是建筑垃圾经分选、破碎、筛分工艺处理后的天然集料替代物，包含了水泥砂浆、原生集料、水泥砂浆与原生集料复合体。沥青混凝土内部界面损伤是沥青路面开裂的主要诱因，探究再生集料对沥青混凝土内部界面损伤的影响，有利于水泥混凝土再生集料在路面工程的推广。本文研究首先采用再生集料制备再生集料沥青混凝土(recycled aggregate asphalt concrete, RAAM),将RAAM中内部界面分为水泥砂浆-沥青砂浆界面(cement mortar-asphalt mastic interface, CMI)和天然集料-沥青砂浆界面(natural aggregate-asphalt mastic interface, NAI),通过电镜扫描试验和X线计算机体层成像(X-ray computed tomography, X-ray CT)试验获取了沥青混凝土内部界面的微细观特征，并采用半圆弯曲试验和有限元模型分析了RAAM的界面力学特征。试验结果表明，再生集料中的附着水泥砂浆具有多孔结构，增加再生集料用量会加剧沥青混凝土高温压缩过程中的内部界面损伤，水泥砂浆内部、水泥砂...

Characteristics of Failure Behavior at The Interface of Recycled Aggregate Asphalt Mixture

: Cement concrete recycled aggregate (RA) is a natural aggregate substitute which is prepared by construction and demolition waste after sorted, crushed and screened processes. It contains cement mortar, primary aggregate, cement mortar and primary aggregate composite. The internal interface damage is the main cause of the cracking of asphalt pavement. To explore the effect of RA on the internal interface damage of asphalt concrete is beneficial to promote the further application of RA in pavement engineering. In this paper, RA was used to prepare recycled aggregate asphalt concrete (RAAM). The internal interfaces in RAAM were divided into cement mortar-asphalt mortar interface (CMI) and natural aggregate-asphalt mortar interface (NAI). SEM and X-RAY CT tests were applied to obtain the microscopic characteristics of the internal interfaces, and the interface mechanical behavior of RAAM was analyzed by semicircle bending test (SCB) and finite element model (FEM). The results show that the cement mortar has a porous structure, increasing the amount of recycled aggregate will aggravate the damage of the internal interface during the high temperature compression, and the connection inside the cement mortar and the cement mortar-asphalt mortar interface (CMI) are the main cause of internal interface damage. The finite element (FEM) simulation results show that with the increase of RA, the fracture dissipation energy of asphalt concrete decreases, and the average value of the interface principal stress increases. This study demonstrates that RA can serve as an effective substitute for natural aggregates after enhancing its attached cement mortar, and provides a reference for the future application of recycled aggregate in road engineering.