Final Scope
Throughout the United States there is widespread use of deicing chemicals during the winter months to prevent the buildup of snow and ice on roadway surfaces and bridge deck slabs. While deployment of deicing chemicals is an effective strategy for maintaining safe, reliable, ice-free roadway surfaces, this practice can lead to chloride contamination in bridge components. Bridges can also be subject to natural sources of chlorides, particularly in coastal and marine environments where components may be exposed to seawater, spray, and mist. The affected bridge components include foundation, substructure, and superstructure elements. Chlorides migrate through the concrete cover and cracks and become concentrated at critical levels. As a result, corrosion of the reinforcement is initiated. This results in concrete spalls, costly repairs, and eventually replacement of bridge components.
To meet this challenge, we can design and construct bridges using corrosion resistant reinforcing bars, which will delay the onset of corrosion and the subsequent deterioration of bridge decks and other structural elements. Material producers have been meeting this challenge by developing bars with improved corrosion resistance by providing bars with different coatings, steel compositions, and alternate materials.
The objective of this synthesis is to document policies and practices used by state departments of transportation (DOTs) related to the use of corrosion resistant reinforcing bars.
Information to be gathered includes (but is not limited to):
- Types of reinforcing bars used, including variations and grades. Examples might include, but are not limited to:
- Black steel;
- Epoxy-coated steels;
- Galvanized steels;
- Steels with multi-layer coatings (e.g., galvanized plua epoxy);
- Alloy steels, such as low-carbon chromium steel;
- Various grades of austenitic, martensitic or duplex stainless steels;
- Stainless steel cladded steels; and
- Fiber-reinforced polymer with various incorporated fiber materials, such as glass, carbon, basalt, etc.
- Bridge components that utilize different types of corrosion resistant reinforcing bars;
- Materials typically specified;
- Concrete cover provided on bridge components in conjunction with alternate materials;
- Types, strengths, and permeability of concrete specified for various reinforcing bars;
- Timeframe DOTs have used for different corrosion resistant reinforcing bars, including how those bars performed, and how the agencies measured the performance (i.e., have agencies seen better performance from their bridge decks);
- Conditions DOTs specified when using various corrosion resistant reinforcing bars, (e.g. material type, exposure, environmental conditions, bridge component);
- Information on life-cycle cost analysis used to justify the selection of an alternate corrosion resistant reinforcement, including any parameters and assumptions;
- What decision-making tools are used in the selection of corrosion resistant reinforcement;
- Material availability of different reinforcement types;
- Efforts to increase the use of corrosion resistant reinforcement;
- Information on any benefits or challenges identified through construction implementation of these materials (e.g. bar field modification, contractor response to alternate materials);
- Methods used for quality control certification of corrosion resistant bars;
- Information on any challenges with dissimilar metals and materials;
- Modifications to standard design practices utilized when specifying different corrosion resistant reinforcing bars (e.g., optimization or adjustments to account for differences in yield or ultimate tensile strengths, modulus of elasticity, etc.); and
- Written policies that govern the application of the various corrosion resistant reinforcing bar types.
Information will be gathered through a literature review, a survey of state DOTs, and follow-up interviews with selected DOTs for the development of case examples. Information gaps and suggestions for research to address those gaps will be identified.
Information Sources (Partial):
- Innovative Bridge Materials at Maine DOT: Use of FRP Composites. TRB 102nd Annual Meeting 2023 Presentation.
- MnDOT Service Life Design Guide for Bridges, https://edocs-public.dot.state.mn.us/edocs_public/DMResultSet/download?docId=15850393
- Fiber Reinforced Polymer Reinforcing. Florida DOT, Fiber Reinforced Polymer Reinforcing (fdot.gov).
- Stainless Steel Coated Rebar for Chloride Resistant Concrete Highways and Bridges. NCHRP IDEA 20-30/IDEA 240.
- Structural Fiber Reinforcement to Reduce Deck Reinforcement and Improve Long-Term Performance, https://www.ugpti.org/resources/reports/details.php?id=989.
- Laboratory Characterization of Fiber-Reinforced Polymer Reinforcement Material Properties and Surface Treatment Behavior in Concrete, Virginia Transportation Research Council.
- Identification of Commercially Available Alloys for Corrosion-resistant Metallic Reinforcement and Test Methods for Evaluating Corrosion-resistant Reinforcement, Virginia Transportation Research Council.
- Investigation of the Corrosion Propagation Characteristics of New Metallic Reinforcing Bars, Virginia Transportation Research Council.
- Testing of Selected Metallic Reinforcing Bars for Extending the Service Life of Future Concrete Bridges: Summary of Conclusions and Recommendations, Virginia Transportation Research Council.
- Corrosion-Resistant Stainless Steel Strands for Prestressed Bridge Piles in Marine Atmospheric Environments, Virginia Transportation Research Council.
- Bridge Deck Service Life Prediction and Costs. Virginia Transportation Research Council.
- Optimal Approach for Addressing Reinforcement Corrosion for Concrete Bridge Decks in Illinois. FHWA-ICT-22-005, ICT-22-005, UILU-2022-2005, https://doi.org/10.36501/0197-9191/22-005.
- Harkers Island Bridge Replacement: Material Characterization and Structural Performance, North Carolina Department of Transportation.
- Cost and environmental analyses of reinforcement alternatives for a concrete bridge, https://doi.org/10.1080/15732479.2019.1662066.
- Field Investigation of Bridge Deck Reinforced with Glass Fiber Reinforced Polymer (GFRP) Rebar. Minnesota Department of Transportation, http://mndot.gov/research/reports/2020/202005.pdf.
- Alternative Reinforcement Products in the Design of Concrete Structures⸺ Durability Performance. Transportation Association of Canada, https://www.tac-atc.ca/sites/default/files/conf_papers/hudecekm_skabars_el-hachar_alternative_reinforcement_products.pdf.
- Toward Non-Corrosion and Highly Sustainable Structural Members by Using Ultra-High-Performance Materials for Transportation Infrastructure [Supporting Dataset] ⸺https://digitalcommons.lsu.edu/transet_pubs/56/.
- Assessment of Bridge Decks with Glass Fiber Reinforced Polymer (GFRP) Reinforcement.⸺ Minnesota Department of Transportation.
TRB Staff (consultant)
Sandra Larson
Phone: 515-971-6329
Email: slarson@nas.edu
Meeting Dates
First Panel: September 19, 2023, Washington, DC
Teleconference with Consultant: October 25, 2023, 1-2 pm Eastern
Second Panel: June 6, 2024, Washington, DC, Keck Center
Panel Members
Mr. Tekeste Amare, Maryland Transportation Authority
Dr. Rodrigo Antunes, Florida Department of Transportation
Mr. James Corney, Utah Department of Transportation
Ms. Arielle Ehrlich, Minnesota Department of Transportation
Ms. Katherine Hoensheid, Michigan Department of Transportation
Mr. Eric D. Yermack, New Jersey Department of Transportation
Mr. Raj Ailaney, Federal Highway Administration (FHWA)
Dr. Nelson H. Gibson, Transportation Research Board