Research On Evaluation Method Of Mixing Uniformity Of Cement Stabilized Macadam Base On Digital Image Technology

The cement stabilized macadam base has high strength and rigidity,good water stability and frost resistance,can effectively bear and transfer the road load,so it has been widely used in the construction of expressway in our country.However,during the mixing process of cement stabilized macadam,the original gradation will be destroyed due to uneven mixing,and the uneven distribution of the coarse and fine aggregate will appear,which will seriously affect the overall strength and stability of the pavement base.In view of the current mixing of cement stabilized macadam,there is no standard method of uniformity evaluation,based on digital image processing technology,this paper has carried out in-depth research,and achieved the following results:(1)On the basis of deeply studying of the general structure of cement stabilized macadam mixing equipment and the structure characteristics of mixer,the mixing technology and mixing process of cement stabilized macadam were analyzed and the main factors influencing the mixing uniformity of cement stabilized macadam were determined.(2)The images of cement stabilized macadam after mixing were processed by digital image processing technology,after a series of processing,such as recovery the image,converting the color image into gray image,histogram equalization,converting the image into binary image,morphological and so on,then the aggregate of images were recognized and classified.So that after processing and analysis of the image can better reflect the distribution of the aggregate particles.(3)Combined with digital image processing technology and quadrilateral static moment theory,the analysis model of cement stabilized macadam mixing uniformity was established and the uniform coefficient and area ratio coefficient were put forward to analyze and evaluate the mixing uniformity of cement stabilized macadam,that is,by analyzing the area of aggregate particles and the distance from aggregate particles to four edges in the image,the uniform coefficient and area ratio coefficient which can reflect the distribution of aggregates are obtained.By analyzing the uniform coefficient and the area ratio coefficient of the image,the range of the uniform coefficient and the area ratio coefficient in the image was obtained when the particle distribution in the image is more uniform.(4)By using the GUI interface development function of MATLAB software,the uniform coefficient and area ratio coefficient algorithm were compiled into the system language and the evaluation system of cement stabilized macadam mixing uniformity was developed.The range of uniform coefficient and aggregate area ratio coefficient were tested and verified by engineering.The results show that the mixing uniformity of fresh cement stabilized macadam can be judged by using the digital image processing technology and the uniformity Evaluation index uniform coefficient and area ratio coefficient.The automatic calculation of aggregate distribution in the image can be realized by using the evaluation system of cement stabilized macadam mixing uniformity and the calculation results are accurate and reliable.