As the nation's infrastructure continues to age, there is a need to effectively and economically monitor and inspect bridges. With the introduction of non-destructive testing technologies such as Ground Penetrating Radar (GPR) for condition assessment of bridge decks, states will be better equipped to inspect, assess, and prioritize transportation funding to maintain, preserve, and improve infrastructure. The objective of the research is to improve the condition assessment of bridge decks through the use of GPR which can increase the speed, effectiveness, and accuracy of inspections. The non-destructive evaluation technique provides information that can be used to identify the potential amount of internal deterioration of a concrete bridge deck that cannot be identified with a visual inspection. As in many other states, New Mexico currently uses the chain drag method in which the inspection of the deck condition is solely based on inspector's subjective interpretation of the sound produced by dragging a chain over the bridge deck. The use of GPR has the potential to greatly improve the quality of the inspections by collecting more reliable and less subjective information on the condition of bridge decks. Through the collection and analysis of data acquired from the GPR on a set of reinforced concrete decks, this research seeks to provide a better understanding of GPR technology, data acquisition, and training needs for adoption of GPR in bridge deck inspections in the state of New Mexico. With a better understanding of the technology, GPR can become and indispensable tool for more informed decisions for the allocation of funds for maintenance and improved asset management. This research improves implementation and provides effective economic methods to employ this technology to improve the inspection and maintenance of bridge infrastructure.

The purpose of this study was to evaluate the reproducibility and accuracy of Ground Penetrating Radar (GPR) in locating delaminations and de-bonding in asphalt concrete overlaid concrete bridge decks. The traditional "chaining" method is a less effective option for finding subsurface defects after an overlay is in place. An infrared thermographic and GPR evaluation was conducted on the I-70 Polk-Quincy viaduct in 1993. A second GPR study was performed in 1997 to evaluate the condition of the bridge deck previous to removal of the existing asphalt overlay and high density concrete overlay and repair of the deteriorated deck. The results of the 1997 GPR study were compared to the results of the 1993 GPR study, the 1998 through 1999 chaining, actual repair areas and portions of the 1989 Geotechnical Unit bridge deck evaluation.

This synthesis will be of interest to state Department of Transportation (DOT) geotechnical, bridge, and pavement engineers, engineering geologists, consultants involved with ground penetrating radar (GPR) investigations for state DOTs, and researchers. It describes the current state of the practice of using GPR for evaluating subsurface conditions for transportation facilities. This was accomplished by conducting a literature search and review and an extensive survey of U.S. and Canadian transportation agencies and practitioners, as well as limited international information collection. GPR is a noninvasive nondestructive tool used in transportation applications such as evaluation and characterization of pavement systems, soils, and environmental problems. This report of the Transportation Research Board presents information on the principles, equipment, logistics, applications, and limitations of GPR pertaining to transportation applications. Selected case studies for which ground truth information is available are presented. In addition, an extensive bibliography and glossary are provided as well as appending information about GPR manufacturers from their literature.

" TRB's second Strategic Highway Research Program (SHRP 2) Report S2-R06A-RR-1: Nondestructive Testing to Identify Concrete Bridge Deck Deterioration identifies nondestructive testing technologies for detecting and characterizing common forms of deterioration in concrete bridge decks.The report also documents the validation of promising technologies, and grades and ranks the technologies based on results of the validations.The main product of this project will be an electronic repository for practitioners, known as the NDToolbox, which will provide information regarding recommended technologies for the detection of a particular deterioration. " -- publisher's description.

Concrete bridge decks require periodic condition assessment and preventive maintenance to extend their useful lifespan. Nondestructive evaluation methods such as Ground Penetrating Radar (GPR) are slowly beginning to replace or complement the manual (visual) assessment of bridge conditions for detecting defects at their early stages. However, GPR scans of bridge decks are frequently cluttered with high amplitude reflections from known parts of the bridge deck, which make the detection of defects low amplitude reflections difficult. One such known part is the embedded steel reinforcement bars known as rebar. This dissertation presents a novel approach to the automated detection of defects in concrete bridge decks by removing known reflections such as rebar from GPR scans of reinforced concrete bridge decks. The algorithm detects reflections from rebar with a frequency-domain pulse detection method, groups detected pulses into clusters, interpolates synthetic rebar reflections based on each cluster, and subtracts the synthetic rebar reflection from the original GPR scan data. This algorithm will facilitate the automated, non-destructive condition assessment of bridge decks.