Evaluation of Multi-Layer Polymer Concrete Overlays

Multi-layer polymer concrete overlays, also known as two-coat and broom and seed polymer concrete bridge deck overlays, have been used in Kansas and other states for a number of years, primarily to extend the life of existing bridge decks. The system involves the application of a polymer on which aggregate is broadcast, followed by a second layer of polymer and aggregate. The system has the advantage of filling existing cracks and providing a waterproof membrane to limit future penetration of water and deicing chemicals to the level of the reinforcing steel. There is, however, a great deal that is not known about the system; specifically, the effectiveness of multi-layer polymer concrete overlays as a corrosion protection system for reinforcing steel in bridge decks has never been evaluated. Key questions involve the impact of wear, age, crack formation, and exposure on the effectiveness of this system. Furthermore, the system is also used in new construction, which places special emphasis on its response to the formation and growth of cracks. In addition, because aggregate is integral with the system, cracks that may penetrate the overlay will be exceedingly difficult to identify in the field. The cost of the overlay is on the order of $40/yd2, not including other costs involved in construction; this represents an approximately 20% increase in the cost of new construction. Although this topic was previously studied in a KTRAN project, the effect of cracks was not. The objective of the study is to evaluate the effectiveness of multi-layer polymer concrete overlays, as applied in Kansas, to protect the concrete and the reinforcing steel in concrete bridge decks when used as both a retrofit and in new construction. The research will evaluate the effects of age, crack formation, and exposure. To accomplish this objective research will involve both laboratory (bench-scale) and field test specimens subjected to realistic exposure conditions. The approach taken in the tests will parallel that used to evaluate other corrosion protection systems, including tests that have been used to evaluate corrosion-resistant reinforcing steel, corrosion inhibitors, and alternative deicing chemicals. Both the laboratory and field tests will evaluate the effectiveness of the system to fill existing cracks and to handle the formation of cracks that occur during the life of a bridge deck, the latter being especially important for application of the system for new deck construction. The scope of the research will be tailored to the needs of the Kansas Department of Transportation (KDOT), including the selection of representative, commercially available versions of the system. Typically, laboratory tests (which provide accelerated aging) are run for two years and field tests for a minimum of five years. Only the first year of the performance of the field specimens will be evaluated, with additional testing funded under an ad hoc contract, if so agreed to by KDOT. The specimens will be monitored for corrosion potential and corrosion rate, and the concrete will be sampled to determine chloride penetration. Overlays will be prepared in accordance with Section 729 of the 2015 Standard Specifications.

Language

• English

Project

• Status: Active
• Funding: $157654
• Contract Numbers:

  KU-23-3

  RE-0855-01

• Sponsor Organizations:

  Kansas Department of Transportation

  Eisenhower State Office Building
  700 SW Harrison Street
  Topeka, KS  United States  66603-3754
• Performing Organizations:

  University of Kansas Center for Research, Incorporated

  2291 Irving Hill Drive, Campus West
  Lawrence, KS  United States  66045
• Principal Investigators:

  Darwin, David

  O'Reilly, Matthew

• Start Date: 20220818
• Expected Completion Date: 20240817
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Bridge decks; Concrete overlays; Corrosion protection; Cracking; Materials and structures protection; Polymers
• Subject Areas: Bridges and other structures; Construction; Highways; Maintenance and Preservation; Materials;

Filing Info

• Accession Number: 01858036
• Record Type: Research project
• Source Agency: Kansas Department of Transportation
• Contract Numbers: KU-23-3, RE-0855-01
• Files: RIP, STATEDOT
• Created Date: Sep 20 2022 12:20PM