Enhanced GPR system for Rapid Assessment of Concrete Bridge Deck Chloride Content

An assessment of chloride infiltration into bridge decks is key to making decisions relating to the type and extent of repair, yet current test methods are time consuming and provide limited local information. Ground penetrating radar (GPR) has shown promise as a potential chloride detection method. However, GPR correlation with chloride content varies from deck to deck and additional data are needed to calibrate for other variables. This project seeks to develop a method that can work for all bridge decks by more fully exploiting the information potential of GPR, and incorporating information from other available NDE methods that will be used to “calibrate” the GPR results to the local deck conditions. Previously collected data on decks which have accompanying chloride sample data will be evaluated and variations from deck-to-deck will be assessed with a parametric study using a well-established electromagnetic modeling program. The results of that modeling effort will suggest companion NDE measurements to calibrate for the deck-to-deck variations. A prototype system will be proposed, and field tested on multiple bridge decks to confirm the feasibility of the method and to develop recommendations and specifications for Phase II development.