This research is focused on the development and application of practical Nondestructive Evaluation (NDE) tools for use in the routine inspection and maintenance of highway bridges to ensure safety. Thermal (infrared) imaging is used to detect and image subsurface damage (delaminations) in concrete. The technology works by imaging temperature variations on the surface of the concrete that result from subsurface damage such as delaminations. Images showing damage are observed in real-time by the inspector, such that on-site assessment can be conducted. A significant advantage of the technology is that it is rapid, non-contact and can be utilized from a distance, such that arms-length bridge access and traffic control are not required. As a result, the technology can be used to rapidly scan large areas of a bridge to identify areas of damage. Additionally, the technology is commercially available in field-hardened configuration suitable for use in the bridge maintenance and inspection environments, and training to use the technology is minimal. The previous pooled fund study entitled TPF-5(152) ¿Development of Hand-held Thermographic Inspection Technologies¿ explored the application of thermal imaging technologies for the NDE of highway bridges. Phase I of the research included experimental testing and field testing by participating states. The outcome of phase I testing included a draft guideline for utilizing thermal imaging to detect deterioration in concrete bridges. The guidelines developed provide procedures for utilizing the technology on concrete exposed to direct sunlight and areas not exposed to direct sunlight (soffits, for example), for which no previous guidelines or procedures existed. Phase I also included developing training materials, training individuals from participating states and field testing of the technology in the field by the participating states. Initial field testing conducted by states and the research team demonstrated several successful applications of the technology, including detecting delaminations in bridge decks, soffits, piers, precast panels and for FRP overlays. Phase II of the research consists of field testing and evaluation of thermal imaging to evaluate the reliability of the technology, validate previously developed guidelines for field use, and evaluate implementation barriers. Participating states will be provided training and hardware for testing within their existing bridge evaluation programs, to identify implementation challenges, evaluate the effectiveness of guidelines, and assess the utility of the technology for bridge condition assessment. The research team, in cooperation with the states, will conduct a series of focused field tests that include field verification of results. These field tests will seek to quantitatively evaluate the capabilities and reliability of the technology under field conditions to validate and improve the guidelines, and support practical implementations of the technology. The outcome of the research will be a new inspection technique for improving bridge safety and identifying repair and maintenance needs.

The goal of this research is to further develop this technology and guidelines for the condition assessment of concrete to help ensure bridge safety and improve the effectiveness of maintenance and repair. The objectives of the research are to: * Quantify the capability and reliability of thermal imaging technology in the field * Put the technology in the field with typical maintenance and inspection personnel to identify and overcome implementation barriers * Field test and validate inspection guidelines for the application of thermal imaging for bridge inspection

To address the research needs, a program of research is proposed with the objectives of validation of the inspection guidelines, validating the capability and reliability of the technology, and identifying implementation barriers. To meet these objectives, the proposed program is focused on field validation of the technology intended to develop a better understanding of the limits of the technology and evaluate its ability to effectively detect damage in concrete bridges. * Provide thermal cameras and training to participating states for conducting field testing of the technology (for states that were not part of the phase I Pooled Fund project) * Study the implementation challenges faced for integrating thermal cameras within traditional paradigms for bridge inspection and maintenance * Validate the effectiveness and reliability of the technology under real condition in the field * Develop methodologies and tools to support implementation in the field, including tools for determining the effectiveness of the technology for on-site environmental conditions.

Expected outcomes and Implementation: The expected outcomes of the research are as follows: * A practically implementable inspection technique for assessing bridge condition to ensure safety and better define maintenance and repair needs * Improved understanding of the capabilities and limitation of thermal imaging for the condition assessment of concrete * Field validation of the capability and reliability of the technology * Validated guidelines that can be used by practitioners for the condition assessment of concrete * Overcome implementation barriers Implementation of the research is expected to include increased use of thermal imaging to improve the quality and effectiveness of bridge evaluations and improved bridge safety. Data developed through the research will provide a measure of the reliability of the technology, such that it can be effectively implemented for condition assessment. The research will also develop improved training materials, focused for the bridge community that can be utilized for future implementation of the technology. State Cost: *Pooled Fund Members not part of Phase I: $30,000/fiscal year for two years. *Pooled Fund Members part of Phase I: $20,000/fiscal year for two years.