ITcon Vol. 13, pg. 86-102, http://www.itcon.org/2008/7

Detecting air pockets for architectural concrete quality assessment using visual sensing

submitted:May 2007
revised:September 2007
published:April 2008
editor(s):Akinci B, Anumba C
authors:Zhenhua Zhu, Ph.D. Student
Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI. USA;
email: zhzhu@umich.edu

Ioannis Brilakis, Assistant Professor
Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI. USA;
email: brilakis@umich.edu
summary:Air pockets, one kind of concrete surface defects, are often created on formed concrete surfaces during concrete construction. Their existence undermines the desired appearance and visual uniformity of architectural concrete. Therefore, measuring the impact of air pockets on the concrete surface in the form of air pockets is vital in assessing the quality of architectural concrete. Traditionally, such measurements are mainly based on in-situ manual inspections, the results of which are subjective and heavily dependent on the inspectorsÂ’ own criteria and experience. Often, inspectors may make different assessments even when inspecting the same concrete surface. In addition, the need for experienced inspectors costs owners or general contractors more in inspection fees. To alleviate these problems, this paper presents a methodology that can measure air pockets quantitatively and automatically. In order to achieve this goal, a high contrast, scaled image of a concrete surface is acquired from a fixed distance range and then a spot filter is used to accurately detect air pockets with the help of an image pyramid. The properties of air pockets (the number, the size, and the occupation area of air pockets) are subsequently calculated. These properties are used to quantify the impact of air pockets on the architectural concrete surface. The methodology is implemented in a C++ based prototype and tested on a database of concrete surface images. Comparisons with manual tests validated its measuring accuracy. As a result, the methodology presented in this paper can increase the reliability of concrete surface quality assessment
keywords:Surface defects, Air pockets, Architectural concrete, Image processing
full text: (PDF file, 0.832 MB)
citation:Zhu Z, Brilakis I (2008). Detecting air pockets for architectural concrete quality assessment using visual sensing, ITcon Vol. 13, Special issue Sensors in Construction and Infrastructure Management, pg. 86-102, http://www.itcon.org/2008/7