Abstract:An approach to form a better artificial roughness of old concrete surface was proposed, and an experimental study was carried out. Firstly, the three-dimensional contour data of the rough surface of old concrete was collected by digital image method, then the data was processed based on fractal theory, and fractal dimension was used to characterize the artificial roughness; Then three-dimensional reorganization of the rough interface was achieved by MATLAB program, so that the accuracy of the digital image method was verified; Finally, the correlation of the roughness and the bonding properties of young on old concrete was investigated. The results show that the artificial roughness is a fractal structure, which can be characterized by fractal dimension; There was a positive correlation of fractal dimension (D) and interfacial bonding properties (R), which can approximately be formulated as ; Digital image method is useful in data acquisition, processing, analysis, as well as the three-dimensional reconstruction of interface morphology.