The analysis of structural characteristics distribution and compressive strength of asphalt mixture SMA-13 in two compaction methods

Abstract

In order to study the influence of different compaction methods on void structural characteristics distribution and compressive strength of SMA-13 asphalt mixture, Marshall compaction instrument and rotary compaction instrument were used in the laboratory to make SMA-13 asphalt mixture specimens with different air voids. CT scanning and image processing were used to extract and compare the changes in parameters such as voids ratio, the number of voids, average equivalent diameter of voids, and void contour fractal dimension of various types of specimens. The compressive strength of various types of SMA-13 asphalt mixture specimens was obtained by uniaxial compression test and triaxial compression test. The results show that the variability of voids ratio, the number of voids, average equivalent diameter of voids, and void contour fractal dimension along the layer of SMA-13 specimens formed by rotary compaction is greater than that of specimens formed by Marshall compaction. The mean value of the number of voids, the mean value of average equivalent diameter of voids and the mean value of void contour fractal dimension of SMA-13 asphalt mixture specimens formed by two compaction methods increase with the increase of air voids. The mean value of the number of voids and the mean value of average equivalent diameter of voids of the specimens formed by Marshall compaction are larger than those of the specimens formed by rotary compaction, and the mean value of void contour fractal dimension of the specimens formed by rotary compaction is larger than that of the specimens formed by Marshall compaction when the air voids is similar. The uniaxial compressive strength and triaxial compressive strength of SMA-13 asphalt mixture under two compaction methods decrease with the increase of the mean value of the number of voids, the mean value of average equivalent diameter of voids and the mean value of void contour fractal dimension.