Digital Image Processing Technique to Indirect Tensile Test of Asphalt Mixtures

A digital image processing technique is used for conventional indirect tensile test of asphalt mixtures, by which non-connect measuring process is realized on the horizontal and vertical deformation of specimen. In this system, the shape and deformation of the specimen are automatically monitored and recorded. Through comparison and Analysis the limitation and superiority of traditional measurement method with the digital image processing technique, it is proved that the latter is more practical. Also, the precision and error of the digital image processing system is tested. It is advanced that Poisson's ratio changes with the stress state of material, and the displacement field of specimen surface at any given time is given in this paper to be used to analyze the local deformation of materials.