Reconstruction and analysis of 3-D profile of fracture surface of concrete

A new experimental technique based on laser triangulation to analyze and re construct 3-D fracture surfaces of concrete was proposed. Results of the re construction of a standard object and of the fracture surface of a concrete specimen showed that this technique has reasonable accuracy. Compared with the traditional analysis methods, this method is very convenient to determ ine the fractal dimension and other parameters of fracture surfaces, since indirect or destructive experimental procedures that are laborious and time -consuming are avoided. Quantitative analysis of roughness and the fractal feature of the fracture surface of concrete was also carried out. According to the value of roughness parameter R-s (i.e. the ratio of actual surface area to projected surface), it is shown that the hue fracture surface area is about 45.4% greater than the nominal fracture area. Two methods of calcu lation of fractal dimension, i.e, modified slit-island technique and vertic al section analysis, were employed and preliminary analysis results indicat ed that the fracture surface of concrete is fractal, with fractal dimension ranging from 2.1 to 2.2. This new technique may be of great help to precis ely measure fracture parameters and eventually improve our understanding of failure mechanisms of concrete. (C) 2000 Elsevier Science Ltd. All rights reserved.