Digitized Measurement of the Cracking Index on the Facings of Concrete Structures

摘要

In civil engineering, the survey of reinforced concrete structures is performed mostly from visual indicators by specialized operators. This paper focuses on the internal swelling of concrete, which is revealed by the cracking at the material surface. The manual survey method consists in estimating the average elongation of the material from the cumulative measurement of cracks thicknesses in 4 directions. To overcome some drawbacks of the manual method, this paper proposes to develop a semi-automated measurement of the cracking index from digital images and image processing tools. This allows us to obtain a more reliable crack index and refined crack characterization. This method has been first tested in laboratory and on a bridge near Nantes in 2012. Finally, the authors have been involved in 2015 on a long-term survey of the stacks of a larger bridge in Nantes. The results of the first-year survey will be reported by the time of the congress in 2016.