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Effect of Initial Scarification and Overlay Treatment Timing on Chloride Concentrations in Concrete Bridge Decks



W. S. Guthrie, Curtis Nolan, Dale P. Bentz


Scarification and overlay (SO) procedures are often performed on concrete bridge decks to minimize the corrosion of reinforcing steel due to chloride ingress. Given the need to develop guidelines for the initial timing of SO treatments, the objectives of this research were to collect information from state department of transportation (DOT) personnel about their SO procedures and, subsequently, to recommend timing of initial SO procedures on concrete bridge decks for preventing the accumulation of corrosion-inducing levels of chlorides and extending deck service life. A questionnaire survey of state DOTs was conducted, and numerical modeling of SO treatments was performed for decks with and decks without stay-in-place metal forms (SIPMFs). Full-factorial numerical modeling was performed through a service life of 50 years to determine the recommended initial timing of SO treatment in each case. The research results show that, overall, bridge decks without SIPMFs can endure longer delays in SO treatment timing than those with SIPMFs; the allowable delay in SO timing ranged from 2 to 6 years for decks with SIPMFs, while the allowable delay ranged from 6 to 18 years for decks without SIPMFs. In addition, the results show that the allowable delay also depends on the original cover depth (OCD). On average, for each additional 0.5 in (12.7 mm) of OCD, the period of additional allowable delay for decks with SIPMFs was 2 years; however, in decks without SIPMFs, the additional allowable delay was 5 years with each additional 0.5 in (12.7 mm) of OCD.
Journal of the Transportation Research Board


Bridge deck, chloride diffusion, overlay, scarification, service life.


Guthrie, W. , Nolan, C. and Bentz, D. (2011), Effect of Initial Scarification and Overlay Treatment Timing on Chloride Concentrations in Concrete Bridge Decks, Journal of the Transportation Research Board, [online], (Accessed April 22, 2024)
Created May 22, 2011, Updated October 12, 2021