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Bridges & Special Structures Design

Underbridge inspection units (UBIUs) that reach from above deck to below.
Department of Transportation

Bridges & Special Structures Design

Effects of Concrete Cure Time on Epoxy Overlay and Sealant Performance

Project Number: SPR-1698

Contract Number: 2016-0069

Status: Complete

Start Date: 07/01/2018

End Date 12/31/2020


Applying flood coats (thin epoxy overlays and healer sealers) improves bridge deck condition and extends service life. The current Michigan Department of Transportation (MDOT) policy is to maintain a total curing period comprising 28 days of wet and dry curing before applying a flood coat on bridge decks with new concrete for patches and repairs. Consequently, the contractors must wait 28 days to start surface preparation for a flood coat application, which increases project completion time, traffic management, and user costs. Therefore, there is an interest to evaluate the possibility of applying a flood coat during the dry curing period. Hence, two performance-based procedures were developed to identify the minimum concrete age to receive a thin epoxy overlay or a healer sealer. Two epoxy overlays and two healer sealers were identified from MDOT approved product lists to evaluate their performance on the standard bridge deck joint repair (BDJR) and Grade DM concrete mixes. The overlay performance was evaluated under standard laboratory conditions, simulated summer exposure conditions, wet and dry conditions, and the outdoor conditions representing southwest Michigan exposure. The performance under outdoor conditions was evaluated during the fall, winter, and summer seasons. The overlay performance was assessed primarily by conducting the tensile bond pull-off strength test. Also, the effectiveness of the overlay against chloride ingress was evaluated. The performance of healer sealers was assessed by evaluating the effectiveness of sealers to prevent chloride ingress through sealed cracks. The experimental results support applying overlays and healer sealers during the dry curing period. The rational and implementable procedures developed through this research evaluate the minimum age of concrete to receive epoxy overlays or healer sealers without compromising concrete durability and overlay/healer sealer performance. Even though the process requires evaluating several parameters, this process needs to be implemented only once per each standard or approved mix resulting in significant savings from project and road user costs.





Research Manager Project Manager Performing Organization
Staff photo of Michael Townley Logo for the Bureau of Bridges and Structures Western Michigan University logo
Michael Townley John Belcher Western Michigan University