Digital Image Analysis Of The Asphalt Mixture Homogeneity

In China, a large proportion of highways is aspect concrete pavement, and will increasemore and more. Asphalt mixture is a kind of polyphase and compound material which is makeup of various materials, The segregation of asphalt mixture is one of the main reasons for thedamage in the early stage of asphalt pavement，so, studying the distribution of internalcomponents of asphalt mixture is uniform or not is important and necessary. Traditionalmethod have maken a great breakthrough in the research of uniformity of asphalt pavement,but its operation is relatively complex、the requirements for equipment testing is high andtraditional method have no explicit index of segregation. In recent years, because the computerimage processing technology is more and more applied to the field of engineering material, theresearch of using image processing technology to analyse uniformity of core samples of asphaltpavement is payed more and more attention. This paper is that using digital image technique toanalyse the two-dimensional index of uniformity of core samples of asphalt mixture on thebasis of research in and abroad China.The test scheme is that: first drilling core samples，and cutting core samples into therequired section; second putting all core samples under the black background, and collectingcross-section images in natural light; last processing these intersected images by thesoftware-matlab. Dividing these cross-sections on the basis of4、6and8equalparts, andusing the software--matlab to calculate all the area Si of granule which is greater than or equalto4.75mm of each part under three partitioning methods. Then separately calculate the areaand the coefficient of variation D1of each section of core sample by which can preliminarilyanalyse the advantage and disadvantage of the three division methods. On that basis,calculating the average value D2of coefficient of variation and coefficient of variation C ofeach core sample’s section, by that can get the distribution of coarse aggregate of core sample’sinterior, that is intensity of segregation of core sample. And further analyse the advantage anddisadvantage of these three division methods.Combining with engineering examples, four core samples were collected in six separateconstruction tenders. Three classification methods, each bid of core samples from thesegregation degree of calculated. Segregation degree of the statistical analysis of the sixSections of the core samples. Obtained six tenders in three classification methods segregationdegree of order. Compared with the degree of segregation in the actual project, shows eight equal portions with six equal results with the actual situation is consistent with a certaindeviation, quartered with the actual situation. From an engineering point of view to verify thefeasibility of the above allocation law.