Fractal–fracture analysis and characterization of impact-fractured surfaces in different types of concrete using digital image analysis and 3D nanomap laser profilometery

The main of objective of this paper is to determine quantitatively the fractal character and texture of fracture surfaces and to investigate their influence on the fracture-related properties in different types of concrete having different interfacial bonding properties and coarse aggregate characteristics. Concretes made with granite and Coldstone limestone aggregate were tested for failure under fast dynamic loading; and the fracture profiles was digitized and analyzed by means of image analysis and laser profilometery. It was deduced that a relatively porous and weak interfacial zone in the concrete with granite particles deferred fractures to reach critical length and thus, more energy is consumed for the coalescence of cracks, resulting in a fracture surface with high degree roughness and fractal dimension. The analysis also indicated that the aggregate changes from smooth and rounded and more to rough and angular there is a corresponding increase in roughness of the fracture surfaces. Finally, it was concluded that the elastic compatibility between the aggregate and matrix disorders the fracture pattern which makes the material ductile and contributes to the understanding of the higher fractal dimension and correspondingly more fracture energy absorption capacity.

► Fractal characterizations of different types of concretes after impact failure are carried out.
► First study to characterize the fracture surface roughness of concrete by means of 3D laser profilometery.
► Higher interfacial zone porosity results in a higher fractal dimension and roughness.
► Fracture energy and toughness correlates very well with the roughness numbers of surface.