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.

" 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 deck is among the most expensive components of a bridge over its lifetime because of the frequent and costly maintenance and rehabilitation required. Currently, the Indiana Department of Transportation (INDOT) performs visual inspections of a bridge deck as the principal means of determining its condition, which enables the inspector to definitively document the surface condition while the unseen condition below the deck surface is left to the inspector's expert judgement. To compensate for this lack of data, INDOT supplements visual inspections with programmatic scheduling for major work actions, which is very effective for INDOT but costly. In this continuing era of funding shortfalls, INDOT commissioned this study to investigate nondestructive testing (NDT) methods to fill their data gap to inform its work action decision. The NDT methods have been shown to accurately locate corrosion and delamination and are a cost-effective alternative. A project level comparison between the NDT methods was performed to show which method, as well as which combination of methods, were the best choices from a cost perspective. A project level analysis of 30 bridge decks was performed, and those costs were compared to the costs of the current INDOT programmatic schedules. Finally, the analysis was expanded to the network level, which included the entire bridge inventory in Indiana. The results of this study indicate that implementing the NDT methods is cost-effective for INDOT at both the project and network levels.

This comprehensive reference details the core test methods for the nondestructive evaluation of bridge decks and overlays, and gives a balanced comment on their strengths and limitations. It covers visual, acoustic, low strain, electro-chemical, and invasive methods, and also looks at novel and emerging methods as wll as the general question of quality control. It also gives guidance on which test methods to specify for various site conditions or needs and on adherence to internationally recognized norms or standards where these exist.

Remote sensing technologies allow for the condition evaluation of bridge decks at near highway speed. Data collection at near highway speed for assessment of the top of the concrete deck and proof of concept testing for the underside of the deck was conducted for surface and subsurface evaluation. 3-D photogrammetry was combined with passive thermography to detect spalls, cracks and delaminations for the top of the concrete bridge deck, while active thermography was investigated for bottom deck surface condition assessment. Successful field demonstrations validated results comparable to MDOT inspections. Recommendations for immediate implementation for condition assessment of the top of a concrete deck are included for introducing the BridgeViewer Remote Camera System into current bridge inspections to provide a photo inventory of the bridge deck captured at 45mph and above using GoPro cameras. The combined optical photogrammetry (3DOBS) and passive thermography technologies provide an objective analysis of spalls, cracks and suspected delaminations while traveling at near highways speed. Using the same 3DOBS technology with higher resolution cameras and slower speeds, cracks can be detected as small as 1/32 in. Laboratory and field demonstrations show active thermography would benefit from further development as a remote sensing technology for condition assessment on the underside of the bridge deck.

The Nondestructive Evaluation (NDE) Section of the Lawrence Livermore National Laboratory has worked with the Federal Highway Administration (FHWA) and California Transportation Administration (Caltrans) to find solutions to inspection of aging bridges and highways. As an example of the magnitude of the aging infrastructure problem, the United States has over 500,000 miles of steel girders in bridges to inspect. In California, there are 26,000 bridges, approximately 3000 are steel, and of the steel bridges 1000 are fracture critical. Fracture critical bridges, those that will fail if a critical member fails, must be inspected routinely to ensure their safety. Corrosion and fatigue damage are two of the major problems that require routine assessment to determine extent of damage. We have developed ultrasonic methods for inspecting bridge pins, limited view computed tomography for inspecting bridge cables and cable anchors, and we are developing infrared imaging methods for inspecting bridge decks. We have proposed NDE solutions to a number of inspection problems that including: (1) evaluating concrete damage with ultrasonic, radiographic, and electromagnetic techniques; (2) assessing bridge scour with acoustic imaging technology; (3) monitoring crack growth with acoustic emission; and (4) determining moisture and salt accretion, intemal strain, and state of cure in concrete with embedded sensors,

An additional study was performed on a newly constructed bridge deck in Midvale, Utah, that was subject to an unexpected rainstorm during construction. Several forms of nondestructive testing, including VEI testing, were performed on the deck. Statistical analysis of the tests permitted assessment of the bridge deck. Comparing VEI testing with these other NDT methods has not been done before, and the results of this work will assist those who are unfamiliar with VEI with interpretation of VEI data in the context of other, more typical NDT techniques.

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.