Studyon Ruttingtest Of Asphalt Mixtureand Analysisofvoid Characteristics

Because the rutting test is simple and intuitive,it is used by our country to evaluate the high temperature anti-rutting performanceof the asphalt mixture.The evaluation index adopted in China is dynamic stability.The index mainly considers the high temperature anti-rutting performance of the asphalt mixture rutting specimen in the creep deformation stage,and can not reflect the characteristics of the asphalt mixture in the whole deformation stage.In order to obtain a reasonable evaluation of asphalt mixture high temperature anti-rutting performance indicators,and found the existence of rutting test problems.Based on the rutting test,this paper makes a detailed study on the rutting test and the rutting test using the CT digital image processing technology.It is important for the improvement and improvement of the rutting test.The specific research contents and achievements are as follows:(1)The design gradation of AC-16 was determined by graphical method.The optimum asphalt dosage of SBS modified asphalt mixture and ordinary asphalt mixture was 4.6%and 4.7%respectively,by the bulk density,Marshall,immersion Marshall,maximum theoretical density and so on.(2)The rutting test of asphalt mixture with different thickness and different asphalt was carried out,and we get the rutting depth,dynamic stability and relative deformation of the index data,Analysis of the relationship between the different evaluation indicators,found that the evaluation of the problems and their respective advantages.Finally,the paper puts forward the suggestion of increasing the rutting depth and cooperating with the dynamic stability index.(3)Using the medical CT scanning equipment to scan the asphalt mixture rutting specimen,the homomorphic filtering method based on Matlab software was used to solve the problem of uneven illumination of imaging images.At the same time,the use of median filter,eliminating the noise of the picture,enhanced the performance of the picture.And then use the Otsu method to select the threshold of the image binarization operation,extract the gap in the picture.Finally,through the t test in the statistical test,it is verified that the mean porosity measured after CT image processing can be used as the overall porosity of the specimen.(4)The void fraction of the asphalt mixture of the asphalt mixture formed by the grinding method is small.The void area in the two-dimensional plane is less than10mm~2,and the number of voids decreases with the increase of the void area After the rutting test,the void fraction and number of voids are obviously reduced.The roughness of the ordinary asphalt mixture specimen is deeper and the void volume is more obvious.The change of the void characteristic is mainly reflected in the small micro gap.