Damage Research For Modified Asphalt Mixture Based On Creep Test And CT Image

The world’s major pavement structure types of road are the asphalt concrete pavement structure and the Cement Concrete Pavement Structure, which are also the major types of Chinese pavement structure. More than80%Expressway use the asphalt concrete as surface layers. Rutting is typical forepart damage about asphalt pavement,80%maintenances of expressway result from rutting. Currently, the forepart rutting damage is the most serious problem about the expressway asphalt pavement in China.This thesis aimed at high-temperature asphalt pavement rutting problems, conduced creep tests for the asphalt mixtures SMA-13and AC-20samples modified by SBS (Styrene Butadiene-Styrene Copolymer), studied the dynamic creep damage law of asphalt mixture in high temperature with micro and macro two levels.Firstly, analyzed the process from the intact to breaking of sample based on creep curve, the whole process was divided into three typical stages which are dense, stable creep and fast creep, The damnification evolution was analyzed by calculating creep energy, regarding craze increment as damnification variable.Secondly, got the CT scan images of the SMA-13sample at different stages, the internal cracking position, region and basic evolvement characteristic of modified asphalt mixtures SMA-13were analyzed through analyzing digital microscopic images of slice and comparing CT images at different stages. MIMICS medical image processing software is used to reconstruct the three-dimensional asphalt mixture sample and generate finite element model. The interior strain characteristic and damnification behavior of local model were analyzed through the ANSYS finite element software. The heterogeneous pavement structure analysis method was discussed, and the proportion relation between model macroscopic strain and asphalt sand equivalent strain peak were calculated at30℃,45℃and55℃。The results of research can provide reference for asphalt pavement structure dynamic response analysis under high-temperature and asphalt mixture design.