Research On The Void And Aggregate Gradation Of Asphalt Mixture Based On The Digital Image Processing Technology

Because of the comfort of driving and ease of construction and maintenance, AsphaltPavement have been widely applied on the road projects. The asphalt mixture is the maincomponents of asphalt pavement. The asphalt and mineral aggregate are the main part ofasphalt mixture, and its path performance is affected by many factors; Among these factors,the void fraction and aggregate gradation of asphalt mixture are the main ones. Thus, thedetecting of void fraction and aggregate gradation of asphalt mixture are the important linksin its quality control. However, there is a contradiction that designing by volume butdetecting by quality in the traditional detection, and it will be easily influenced by the humanfactors. With the development of computer and Digital Image Processing technology, theMeso Research of asphalt mixture is gradually favored by scholars; and the new way todetecting of void fraction and aggregate gradation of asphalt mixture by this method is alsobeing paid more attention by researchers.This paper obtain the images from the inside section of the asphalt mixture using theCT technology, process the images using the digital image processing techniques, and thensegment the aggregates, asphalt and voids of the asphalt mixture. Based on the above work,we can make research on the void fraction and aggregate gradation of asphalt mixture. In thestudy of void, this paper mainly research on the measure of void fraction, the distribution ofthe void in the longitudinal direction of the asphalt mixture, and the proportion of differentsize void. From the research we can see that: The measure of void fraction which has a highaccuracy based on the CT technology and DIP method, less affected by human factors; thedistribution of the void in the longitudinal direction of the asphalt mixture is nonuniform.Small void occupy the largest proportion of the different size void. In the study of thedetection of the aggregate gradation we can find that: The pseudo three-dimensional imagesof the asphalt mixture obtained by the CT technology which can gain exact recognition of the coarse aggregate; However, the recognition of the fine aggregate is inexact. We can getstable recognition results by making statistics of more than40images. After doing theconversion of the stable recognition results we can find that: The detection of the aggregategradation which grain diameter greater than4.75mm can get a high accuracy, grain diameterin the range of2.36~4.75mm need to be simple fix due to the impact of image segmentation,the recognition results of coarse aggregate detection is good after correction, the error iswithin5%, meet the requirements of engineering.