基于内聚力模型水泥稳定碎石的抗裂性能

Crack Resistance of Cement-Stabilized Macadam Based on Cohesive Zone Model

摘要:

开发了以内聚力模型为本构单元的离散元模拟方法模拟半圆弯曲试验，通过裂缝数量、裂缝发展、开裂界面占比和接触力链从细观角度分析了级配类型、橡胶粉类型和再生集料对水泥稳定碎石（CSM）抗裂性能的影响。结果表明：CSM开裂可分为裂缝萌发、裂缝发展和裂缝贯穿三阶段；抗裂型级配与橡胶粉通过应力分散增强混合料抗裂性能，抗裂型级配在三阶段均发挥较强的作用，普通橡胶粉主要作用于裂缝发展阶段，改性橡胶粉与水泥界面黏结增强提升了混合料的抗裂性能，且主要作用于裂缝萌发和裂缝发展阶段；再生集料强度低且与水泥界面黏结差，其掺量越高混合料抗裂性能的降幅越大。

Abstract:

A discrete element simulation method based on cohesive zone models was developed to simulate the semi-circular bending test. The effects of gradation type， rubber powder type， and recycled aggregate on the crack resistance of cement-stabilized macadam（CSM） were analyzed from a mesoscopic perspective by examining the crack quantity， crack propagation patterns， cracked interface ratio， and contact force chains distributions. The results show that cracking of CSM can be divided into three stages—crack initiation， crack propagation and crack penetration. Crack-resistant gradation and rubber powder enhance the crack resistance of CSM by dispersing stress concentrations. The crack-resistant gradation exerts significant effects in all three stages. The ordinary rubber powder primarily acts in the crack propagation stage. Modified rubber powder strengthens the rubber-cement interfacial bonding， thereby delaying crack initiation and crack propagation stage. Recycled aggregates have low strength and poor interface adhesion with cement， and the higher the recycled aggregates contents， the greater the reduction in the crack resistance of the mixtures.