Construction and Condition Assessment of Concrete Bridge Decks and Decision Thresholds for Deck Rehabilitation and Replacement: State of the Practice (05-0601)
John Hema, CMC Americas
W. Spencer Guthrie, Brigham Young University

The deterioration of concrete bridge decks nationwide mandates increasingly cost-effective strategies for bridge deck maintenance, rehabilitation, and replacement (MR&R) by transportation agencies. In this research, a detailed questionnaire survey was conducted of 28 state departments of transportation (DOTs) to investigate the state of the practice concerning specific issues of concrete bridge deck management in climates with freezing temperatures. The survey addressed deck construction, winter deck maintenance, deck deterioration, deck condition assessment, and decision thresholds for deck rehabilitation and replacement. The survey results indicate that the most common causes of bridge deck deterioration are chloride-induced corrosion and freeze-thaw cycling and that distress is most frequently manifested as cracking, delaminations, joint spalling, potholes, and scaling. To mitigate the adverse effects of deicing chemicals on deck performance, DOTs are employing preventative measures such as increasing concrete cover over the reinforcement, using epoxy-coated reinforcement, including certain admixtures in the concrete mixture, and requiring proper concrete curing. The most common methods for assessing bridge deck condition are visual inspection, chaining, chloride concentration testing, coring, and half-cell potential testing. Generally, a full-deck replacement is considered when approximately 20 percent to 50 percent of the deck area exhibits deterioration exceeding permissible severity levels for various distresses. The results of this comprehensive questionnaire survey represent years of experience and research by state DOTs and should be particularly useful to consulting engineers and engineers in local governments involved in rating concrete bridge deck condition and programming MR&R strategies at both the project and network levels of bridge management.