Analysis of Crack Propagation using Digital Image Correlation Technique

Abstract

The process of fracture in Fibre Reinforced structures of Concrete is difficult as it is related with the generation of both the micro and the major cracks. The behaviour of fractures is also associated with other phenomena like localization of strain, bridging of cracks and depends mainly on heterogeneity nature of the mix of concrete, type of reinforcement used, and also the concrete and specific properties of reinforcement. The primary purpose of this study is to probe the mode I type of crack propagation in the reinforced concrete beams by the technique called Digital Image Correlation (DIC). The DIC technique is a vigorous, non-contact well defined tool for fracture or crack measurements. Images are captured at altered stages of loading. By comparing these captured images during testing, it is achievable to deduce the deformation of object under external loads. In this thesis, the correlation between the properties of fracture and the concrete properties, with the fibre reinforcement are investigated experimentally at first and then analyzed on the software GOM Correlate by Webinar. The fibres used in this investigation are Flat Crimped Xorex Steel fibres of length 50 mm and width 3.5mm and Procon M Polypropylene fibres of length 19 mm and diameter 38 micro-meter, i.e. aspect ratio of 500. The Tests were carried out on fibre reinforced concrete beam samples by Four Point Flexural Bending. With the help of the DIC technique, the identification of cracking pattern and the fracture properties of fibre reinforced concrete can be analyzed. The DIC technique has turned out as an efficient way to determine the crack opening displacements.