Browsing by Author "Pyc, Wioleta A."

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    Field performance of epoxy-coated reinforcing steel in Virginia bridge decks
    Pyc, Wioleta A.; Weyers, Richard E.; Weyers, Ryan M.; Mokarem, David W.; Jerzy Zemajtis; Sprinkel, Michael M.; Dillard, John G. (Virginia Center for Transportation Innovation and Research, 2000-02-01)
    In this study, the corrosion protection performance of epoxy-coated reinforcing steel (ECR) was evaluated using approximately 250 concrete cores from 18 bridge decks in Virginia. The decks were 2 to 20 years old at the time of the investigation. The deck field inspections included a crack survey and cover depth determination in the right traffic lane. A maximum of 12 cores with the top reinforcement randomly located in the lowest 12th percentile cover depth were taken from each bridge deck. Because of the safety concerns associated with taking cores from the lower steel mat, and to minimize damage to the bridge, a maximum of only 3 cores were taken through the truss bars. The laboratory evaluation of the concrete cores included a visual examination and a determination of the carbonation depth, moisture content, absorption, percent saturation, and chloride content at a 13-mm depth. The rapid chloride permeability test was also performed for the surface and base concrete on samples obtained from the cores taken through the truss bars to determine chloride permeability. The ECR inspection consisted of a visual examination, a damage evaluation, and a determination of coating thickness and adhesion. The condition of the steel underneath the epoxy coating was also evaluated. Adhesion loss of the epoxy coating to the steel surface was detected in all but one deck that was 4 years old and older. The epoxy coatings were debonding from the reinforcing bars. Whereas a bonded coating can be expected to protect the steel, a debonded coating allows chlorides, moisture, and oxygen to reach the steel and initiate a rapid corrosion mechanism. Reinforcing bars in various stages of adhesion loss showed visible signs of a corrosion process underneath the coating, suggesting that ECR will provide little or no additional service life for concrete bridge decks in comparison to bare steel. Other systems that will provide longer protection against chloride-induced corrosion of the reinforcing steel with a higher degree of reliability should be considered.
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    Field Performance of Epoxy-Coated Reinforcing Steel in Virginia Bridge Decks
    Pyc, Wioleta A. (Virginia Tech, 1998-09-04)
    The corrosion protection performance of epoxy-coated reinforcing steel (ECR) was evaluated in 18 concrete bridge decks in Virginia in 1997. The decks were 2 to 20 years old at the time of the investigation. The concrete bridge deck inspections included crack survey and cover depth determination in the right traffic lane. Maximum of 12 cores with the top reinforcement randomly located in the lowest 12th percentile cover depth and 3 cores with the truss bars were drilled from each bridge deck. The concrete core evaluation included visual examination and determination of carbonation depth, moisture content, absorption, percent saturation and chloride content at 13 mm depth. Rapid chloride permeability test was also performed for the surface and base concrete on samples obtained from cores containing truss bars. The ECR inspection consisted of visual examination and damage evaluation, coating thickness and adhesion determination. The condition of the steel underneath the epoxy coating was also evaluated. Adhesion loss of the epoxy coating to the steel surface was detected for 4 years old bridge decks. The epoxy coating had debonded from the reinforcing bar before the chloride arrival. Visible signs of a possibility of a corrosion process underneath the coating suggest that ECR will not provide any or little additional service life for concrete bridge decks in comparison to black steel. Other systems, which will provide longer protection with a higher degree of reliability against chloride induced corrosion of steel in concrete, should be considered.
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    Performance Evaluation of Epoxy-Coated Reinforcing Steel and Corrosion Inhibitors in a Simulated Concrete Pore Water Solution
    Pyc, Wioleta A. (Virginia Tech, 1998-02-14)
    Three epoxy-coated reinforcing steel (ECR) types removed from job sites, one shipped directly from the coater's plant, three commercial corrosion inhibitors, and one ECR plus a corrosion inhibitor were evaluated as reinforcing steel corrosion protection systems against chloride induced corrosion. The three corrosion inhibitors were calcium nitrite, an aqueous mixture of esters and amines, and a mixture of alcohol and amine. The ECR was tested in two groups, 0% and 1% coating damage. Corrosion protection performance was evaluated by the amount of visually observed blister surface area, for the ECR, and corroded surface area, for the tested corrosion inhibitors. Results of the ECR testing demonstrated that coating debondment and corrosion of ECR is directly related to the amount of damage present in the coating, as well as coating thickness. For the bare steel tested with and without corrosion inhibitors, the results showed that corrosion increases with increasing chloride concentrations. Corrosion inhibition characteristics were demonstrated only by the calcium nitrite corrosion inhibitor. A corrosion protection evaluation test was developed for concrete corrosion inhibitor admixtures. The test solution is a simulated concrete pore water. Corrosion is accelerated by evaluating the temperature to field conditions of 40 C. The test consists of a 7 day pretreatment period followed by a 90 day test period. The corrosive sodium chloride is added to the solution containing the bare or epoxy-coated reinforcing steel specimens after the 7 day pretreatment period. In addition, the solution is periodically saturated with oxygen.