Evaluation of impulse response & ground-penetrating radar as a means of non-destructive testing of concrete bridge decks
University of Delaware
Nationwide, a significant percentage of decks of reinforced and prestressed concrete bridges are exposed, not only to a growing traffic volume, but also to an increasingly aggressive environment. These conditions can lead to shallow delamination within the deck. Once large portions of the deck are delaminated, the function of the deck as integral part of the structure may become questionable. So far, transportation agencies have used simple visual inspection methods, which are often subjective and qualitative, to locate deteriorated areas for repair. These methods give only a rough estimate of the location of the actual deterioration and give no information about the depth of the delamination. In this thesis the effectiveness of two methods of non-destructive testing and their ability to predict the depth and extent of shallow delaminations in concrete bridge decks are discussed. Current practice of Impulse Response and Ground-Penetrating Radar testing is reviewed, performed (either in the field or in the lab), and evaluated. Modifications to these practices are suggested to customize each method specifically to delamination testing. If used properly, these new test procedures may help bridge owners to more accurately estimate delaminations and their depths which will help to better predict rehabilitation costs.