Digital Imaging Methodology for Measuring Early Shrinkage Cracking in Concrete

The measurement of early shrinkage cracking in concrete is important to prevent aesthetic issues and avoid surface cracking that could lead to reinforcement corrosion and reduce the durability, long‐term service life and integrity of a structure. Moreover, the lack of standards and subjectivity of the very few methodologies proposed so far complicate its estimation. This research presents a new imaging methodology for evaluating and quantifying early shrinkage cracking patterns. The methodology was developed testing highly restrained square concrete slabs subjected to severe conditions of restraint and moisture loss. Its quantification consisted of photographing, processing the pictures and highlighting the cracks. For the first time, early shrinkage cracking in concrete can be measured through an experimental technique and quantified by means of geometric figures. In this way, more precise and automatic results are achieved, as flat figures adapt to the shape of cracks and store their properties. Therefore, parameters such as the total cracked area, total crack length, maximum crack width or average crack width were easily calculated. The results demonstrated the suitability of the wind tunnel test to produce significant cracking patterns, as well as the great capacity of the imaging methodology to identify and characterize the cracking pattern.