U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
This techbrief is an archived publication and may contain dated technical, contact, and link information |
|
Publication Number: FHWA-HRT-09-070
Date: October 2009 |
High Performance Concrete Bridge Deck InvestigationFHWA Contact: Ben Graybeal, PDF Version (518 KB) PDF files can be viewed with the Acrobat® Reader® This document is a technical summary of the unpublished Federal Highway Administration report, High Performance Concrete Bridge Deck Investigation, available only through the National Technical Information Service (NTIS). NTIS Accession No. of the report covered in this TechBrief: PB2009-115497 OBJECTIVEThis TechBrief provides a summary of an investigation that assessed the performance of high performance concrete (HPC) bridge decks. HPCHPC is a concrete designed to meet a performance specification. Many definitions of HPC have been proposed over the past 15–20 years; one to note is the definition proposed by Goodspeed and later expanded by Russell and Ozyildirim that offers a series of strength and durability-related performance characteristics.(1,2) It recommends that the desired performance of the concrete should be considered and that the performance characteristics should then be set accordingly. Example performance characteristics toward which concrete properties may be focused include chloride penetration, shrinkage, compressive strength, and freeze/thaw deterioration resistance. BACKGROUNDIn 1993, the Federal Highway Administration (FHWA) initiated a national program to implement the use of HPC in bridges. The program included the construction of demonstration bridges throughout the United States. As a result, State transportation departments started implementing HPC in their bridges. The construction of these bridges has provided researchers with a large amount of data on the use of HPC. Information about the 18 bridges included in the FHWA program in addition to one bridge in Louisiana was compiled and reported.(3,4)A compact disc (CD) containing the compilation was prepared. The CD contained photographs and cross sectional drawings of the bridges, as well as details about the materials and methods used in construction. Elevation photos of two of these bridges are shown in figure 1 and figure 2.
INVESTIGATION PROCESSAfter the bridges were in service for several years, the decks were assessed, and their performance was evaluated relative to the compiled data. The investigations into the performance of the decks included four specific tasks. First, all relevant information pertaining to the construction of the bridge deck was collected. This included items such as concrete mix design, construction practices during and after concrete placement, average daily traffic on the bridge, and maintenance performed. Second, each deck was inspected. This task included standard visual inspection practices, as well as the completion of a detailed crack assessment. Concrete cores were also acquired from select locations. Next, the collected information was evaluated to assess the performance of the decks. Last, the results were documented in individual reports pertaining to each deck. These individual reports can be found in the appendix of the corresponding main report. The 19 bridge decks investigated are listed in table 1. Table 1. Bridge decks investigated in this study.
RESULTSThis investigation demonstrated that HPC bridge decks can be constructed to perform well, and they exhibit relatively few cracks after multiple years of service. The investigation did not identify any significant spalling or delamination in any of the decks. RECOMMENDATIONSFrom the data obtained from this study, recommendations on basic concrete mix design parameters have been proposed. Less cracking is anticipated to occur in concrete bridge decks constructed with water-to-cementitious material ratios between 0.35 and 0.40 and cementitious material content between 600 and 700 lb/yd3 (356 and 415 kg/m3). Mixes meeting these recommendations are anticipated to possess low to moderate ranges of rapid chloride permeability. Application of appropriate construction practices is also recommended. REFERENCES
|
Researchers-The technical contract oversight was provided by Ben Graybeal who is the Structural Concrete Research Program Manager at the Federal Highway Administration's (FHWA) Turner-Fairbank Highway Research Center. Additional information can be obtained by contacting him at 202‑493‑3122 or in the FHWA Office of Infrastructure Research and Development located at 6300 Georgetown Pike, McLean, VA, 22101. Distribution—The unpublished report (PB2009-115497) covered in this TechBrief is being distributed through the National Technical Information Service, www.ntis.gov. Availability—The report will be available in November 2009, and it can be obtained from the National Technical Information Service, www.ntis.gov. Key Words—Bridge, Cast-in-place concrete, Cementitious material content, Crack density, Deck, Durability, High-performance concrete, HPC, Precast concrete, Prestressed concrete, and Water-to-cementitious material ratio. Notice—This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers' names appear in this TechBrief only because they are considered essential to the objective of the document. Quality Assurance Statement—The Federal Highway Administration provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement. |