Concrete Bridge Deck Condition Assessment and Improvement Strategies

The aging and deterioration of bridges in Utah mandates increasingly cost-effective strategies for bridge maintenance, rehabilitation, and repair (MR&R). Although the substructures and superstructures of bridges in Utah are in relatively good structural condition, the bridge decks are deteriorating more rapidly due to the routine application of deicing salts, repeated freeze-thaw cycles, and other damaging effects. Therefore, the Utah Department of Transportation (UDOT) initiated this research to ultimately develop a protocol offering guidance about when and how a bridge deck should be rehabilitated or when it should be replaced. The research specifically focused on concrete bridge deck performance issues, condition assessment techniques, rehabilitation methods, and bridge management system (BMS) concepts. An extensive literature review was conducted to identify condition assessment methods used to detect concrete bridge deck deterioration, as well as to identify rehabilitation methods for deck repairs. A questionnaire survey was also conducted to identify the state of the practice for bridge deck management by state departments of transportation (DOTs) throughout the United States. The survey addressed issues such as climate and traffic information, new deck construction, winter deck maintenance, deck deterioration, deck condition assessment, and deck rehabilitation. The results of the research show that a bridge deck management system is essential in maintaining the integrity of reinforced concrete bridge decks. Developing a successful system requires routine inspection and monitoring to enable prioritization of MR&R strategies for individual bridges. Many types of technologies are available for assessing the condition of concrete bridge decks, but the survey results suggest that only five methods are frequently used to monitor and detect bridge deck deterioration. These methods are visual inspection, chaining, chloride concentration testing, coring, and half-cell potential testing. The survey identified chloride-induced corrosion, freeze-thaw cycling, and poor construction practices as the most common sources of bridge deck deterioration. Results also indicate that distress is most frequently manifested as cracking, delaminations, spalling, potholes, and scaling. Generally, the extent of deterioration that constitutes a full-deck replacement was given by survey respondents as 30 to 50 percent of the deck area. One of the major contributors to bridge deck deterioration is winter deck maintenance. To mitigate the negative effects of deicing chemicals, DOTs are employing preventative measures such as increasing concrete cover over the reinforcement, using epoxy-coated reinforcement, including appropriate admixtures in the concrete mixture, and facilitating proper curing of the concrete. Rehabilitation options listed for bridge decks include electrochemical rehabilitation, concrete removal and patching, surface treatments, and epoxy injections. UDOT should develop and implement a formal BMS with a searchable database containing information about the types of distress manifested on individual bridges, causes for the distress, values of measured test parameters, types of rehabilitation methods performed on the bridge deck, costs for rehabilitation methods, and service life extensions as a result of particular rehabilitation methods. Supporting data should be regularly collected through inspection and monitoring programs to facilitate prioritization of MR&R strategies for individual bridges and to evaluate the impact of such strategies on the overall condition of the network. Performance indices based on selected condition assessment parameters should be developed for use in BMS analyses, and mathematical deterioration models should be calibrated for forecasting network condition and predicting funding requirements for various possible MR&R strategies.