This project developed and tested a new class of non-toxic water-based inorganic polymer coatings for corrosion protection of concrete reinforcing steel rebars for highway applications. A.C. (alternating current) impedance spectroscopy and salt fog tests were conducted on polymer coatings applied to steel panels and bars. Based on test results, coating formulations with superior corrosion protection characteristics were identified. Of these, two formulations were selected for evaluation by the ASTM G109 test for corrosion protection. Tests on coated steel reinforcing rebars in concrete have been under way for over 15 months at the Florida DOT. Initial results showed no noticeable corrosion activity on coated rebars. To accelerate the onset of corrosion, the saline concentration of the test solution was raised. Results to date for coated rebars have been very promising and Florida DOT has decided to continue monitoring of the specimens beyond the completion of this IDEA project.
A number of options for implementing the results within highway practice are possible. Once the passivating coatings are certified for use by the Federal Highway Administration and state departments of transportation, the next step for implementation will be providing commercial quantities of inorganic polymer coatings. One option for Neely Industries, Inc. (NI) to provide such quantities would be by licensing the technology to established coating manufacturers, a strategy successfully utilized by NI for other product developments. Companies interested in licensing high performance, environmentally friendly coatings have been identified. Another option is the formation of a joint venture company to manufacture the coatings. A partner company for this approach has been identified. The regional manufacture of coated rebar will be done by licensing individual fabrication and coating companies. The final report is available from the National Technical Information Service (NTIS # PB2001-104274).
The final report for this IDEA project can be found at:
https://www.trb.org/studies/idea/finalreports/highway/NCHRP052_Final_Report.pdf
