Multi-scale study on bending fatigue damage strength of asphalt mixture

LI Youyun; WANG Bin; GAO Yingli; LYU Yan

doi:10.16186/j.cnki.1673-9787.2023030028

Abstract：Objectives To validate the effectiveness of multi-scale numerical simulation methods in predict-ing the variation of flexural strength parameters during the fatigue damage process of asphalt mixtures in semi-circular bending tests.Methods Based on the multi-scale algorithm concept and the semi-circular bending test,a micro-structure analysis of asphalt mixture specimens is conducted to determine the distribu-tion pattern of geometric characteristics of internal aggregate particles;on this basis,the asphalt mixture was divided into five micro-region scales,and finite element models(FEM)of the semi-circular bending specimens at these scales were constructed.The multi-scale iterative calculation was then used to predict the flexural strength of asphalt mixtures at different semi-circular bending fatigue damage levels of 0%Nf,20%Nf,50%Nf,65%Nf,and 80%Nf(Nf denotes the fatigue life).The flexural strength parameters of as-phalt mixtures with different particle sizes obtained from indoor semi-circular bending tests were used as macroscopic verification experiments,and a comparative analysis was conducted with the flexural strength obtained from multi-scale algorithm numerical simulation experiments.Results The results show that in the fatigue damage process of asphalt mixtures,the decay rate of flexural strength is relatively slow in the early stage,but enters a rapid decline phase in the middle and later stages,the decay patterns obtained from the multi-scale numerical simulation tests are consistent with those from indoor tests,with the absolute value of the relative error in flexural strength controlled within 8%.Conclusions The multi-scale numerical simula-tion is effective in predicting the flexural strength parameters of asphalt mixtures during the fatigue process.This algorithm can provide a reference for similar practical engineering projects.