Late Life Low Cost Deck Overlays - TR-775

Low-slump dense concrete overlays (LSDC) are typically used by the Iowa DOT to provide long-term performance. However, due to their relatively high costs and long curing, LSDC overlays may not be the optimal solution for late-life bridge decks that require a short service life extension prior to replacement. A literature review and cost-benefit analysis were conducted to identify potential late-life overlays that are less expensive and have a smaller traffic impact than the LSDC overlay. Federal and state research on overlays and the standards of eleven states in the Midwest and three additional states (California, New York, and Virginia) were reviewed. Seven types of overlays were selected for comparison to the LSDC overlay as follows: LMCVE, PPCO, thin polymer, HMA overlays, PMA overlays, and HMA overlays with waterproofing membranes (WPM). Reinforced asphalt overlays were also identified as potential late-life overlays, but due to lack of data and literature, could not be included in the analysis. A reduced construction procedure that does not require partial-depth repairs was also considered in addition to the standard procedure used by the Iowa DOT. Results of the analysis show that all of the overlays investigated can reduce the traffic closures by half the time and several overlay-construction procedure combinations can significantly reduce the cost compared with the LSDC overlay. Recommendations for selecting the optimal late life overlays based on the targeted remaining service life were presented in terms of a decision making table that classifies the different options based on cost, traffic closure times, and expected service life. Field studies are recommended to verify the benefits of and service life associated with the reduced construction procedure discussed in this study. Additionally, it is recommended that a more refined cost-benefit analysis be conducted for bridges with varying deck conditions and service life requirements to confirm the general applicability of the results of this study