| The main research object of this paper is the vacuum compacted hot mix asphalt mixture.By using different testing compaction device,in the condition of three different vacuum degree(0/-0.06MPa/-0.08MPa),we analyzed the influence of compaction on the fine microstructure of hot mix asphalt mixture.The main contents are testing the four conditions of specimen porosity.Macroscopically,the void content tests were carried out on 4 kinds of working conditions;on the meso scale,the cross sectional images of the asphalt mixture inside 12 specimens were obtained by CT scanning in 4 working conditions.Using image processing software and MATLAB software to analyze the image of each fault,the vertical meso void characteristics of asphalt mixture are obtained,combined with the Marshall stability test of asphalt mixtures,analyzing the influence of microstructure on macroscopic properties asphalt mixture;Microscopically,the adhesion of asphalt mortar aggregate interface under different working conditions was observed by stereo microscope and the influence of microstructure of asphalt mixture on macro performance was analyzed combined with the splitting test results.Under the same test conditions,vacuum compaction can effectively reduce the void content and average equivalent diameter of asphalt mixture,and the larger the degree of vacuum,the smaller the average void diameter and void equivalent diameter of asphalt mixture;Vacuum compaction can improve the internal void gradation of asphalt mixture.With the increase of vacuum degree,the proportion of small holes in the voids of the mixture increases,and the proportion of large voids decreases;Vacuum compaction can strengthen the bonding property of asphalt mortar aggregate interface,and improve the microstructure of asphalt mixture;With the increase of vacuum degree,the crack width at the interface of asphalt mortar will be more narrow and the number of cracks in the asphalt mixture decreases obviously. |
PDF Full Text Request