Concrete bridge deck overlays have been used in the United States since 1960 to extend the service life of deteriorated concrete bridge decks and improve reliability. Concrete bridge decks with overlays suffer various types of deterioration, so it is necessary to identify and assess the effectiveness of different nondestructive evaluation (NDE) technologies in the laboratory under controlled conditions and in the field under actual conditions. This report provides an overview of seven types of widely used overlays: asphalt with a liquid membrane, asphalt with a fabric membrane, asphalt without a membrane, silica fume-modified concrete, latex-modified concrete (LMC), epoxy polymer concrete, and polyester polymer concrete. This report identifies and ranks available and promising NDE technologies to assess the performance of different types of overlays and concrete bridge decks. This report describes laboratory validation on overlays for nine commonly used NDE technologies. The nine NDE technologies are: sounding, ultrasonic surface waves (USW), impact echo (IE), ultrasonic tomography (UT), impulse response (IR), ground-penetrating radar (GPR), electrical resistivity (ER), half-cell potential (HCP), and infrared thermography (IRT). This report details the results of laboratory tests validating the NDE technologies for the seven different types of overlays. Field validation using the RABITTM bridge deck assessment tool and manual testing equipment was also performed. Results from the study on which this report is based indicated that GPR was the most effective method for detecting defects in underlying concrete specimens through both bonded and debonded overlays; however, GPR could not detect overlay debonding. Results also showed that USW, IE, and UT were effective stress-wave-based methods for detecting defects under bonded overlays but not asphalt overlays. Researchers found that asphalt overlays at low temperatures (i.e., 32°F or below) improved the applicability of

Concrete corrosion induced by deicing agents can decrease the durability of concrete bridge decks by causing cross-sectional loss of reinforcement, concrete delamination, and spalling owing to the expansion of corroded reinforcement. The installation of overlays can extend the service life of the deteriorated decks. However, overlays present challenges in the evaluation of the corrosion condition of the underlying decks. This laboratory study employed three nondestructive testing (NDT) methods to assess the effects of seven types of overlays on corrosion evaluation for concrete bridge decks. The NDT methods were electrical resistivity (ER), ground-penetrating radar (GPR), and half-cell potential (HCP). The ER method could not evaluate the corrosive environment in the concrete decks through the overlays. The GPR method could detect the corrosive environment through four of the seven overlays. The HCP method could detect the decrease of electrical potential over the actively corroded reinforcement for all seven specimens; however, only two of the seven specimens could be identified as having active corrosion per ASTM C876-15, Standard Test Method for Corrosion Potentials of Uncoated Reinforcing Steel in Concrete . Overlay debonding did not affect GPR and HCP testing results in this study.

" 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.

The state of Wyoming alone has 13.1 million square feet of bridge deck, and evaluation of those decks has become an important part of the Wyoming Department of Transportation's (WYDOT) management of bridge repairs. The authors believe that development and advancement of nondestructive evaluation methods over the past 25 years may provide a more efficient, standardized, and accurate method for evaluating bridge deck conditions compared with current practices. A study was performed on three bridge decks in Wyoming: the First Street Bridge in Casper, the Douglas I-25 Bridge, and the Remount I-80 Bridge. For each bridge, an investigation was done using standard WYDOT practices for chain dragging. In addition, the bridges were evaluated using impact echo, thermal imaging, and ground-penetrating radar (GPR) techniques. All three methods considered were successful, and the damage locations between the impact echo, thermal imaging, and GPR generally correlated well. Based on this study, a complete bridge deck evaluation should combine impact echo with GPR testing to provide the most accurate predictions of delamination and debonding in support of optimal maintenance decisions.

An objective view of the relative advantages and limitations of the nondestructive testing and evaluation methods that are currently used in the inspection of bridge decks is presented and discussed. The three main nondestructive testing technologies that were evaluated are impact-echo, ground penetrating radar, and infrared thermography. Nondestructive testing and evaluation procedures, including methodology and equipment to evaluate concrete bridge decks with asphalt overlays, are also presented and discussed. Current results indicate that a combination of ground penetrating radar and infrared thermography would provide the best methodology for evaluating the structural integrity, e.g., delaminations, of concrete bridge decks with overlays. Furthermore, current results also indicate that the impact-echo method shows promising future development towards the nondestructive evaluation of bridge superstructures.

This research has examined the use of nondestructive techniques for concrete bridge deck condition assessments. The primary nondestructive testing/evaluation (NDT/NDE) technique utilized in this research was ground-coupled ground penetrating radar (GPR). The objectives of this research were to examine the utility of the nondestructive techniques in evaluating the condition of MoDOT bridge decks to enable faster, better, and more cost-effective bridge deck assessments, and to determine the accuracy of the information provided.