Evaluation of Dowel Bar Retrofits for Local Road Pavements

As truck traffic on Iowa secondary roads has increased, engineers have moved to concrete pavements of greater depths. Early designs included thickened edge pavements and depths of seven inches or greater. The designs typically did not have load transfer devices installed in the transverse joints and relied on aggregate interlock for this purpose. In some cases, aggregate interlock was not adequate to deal with the soils and traffic conditions and faulting of the joints has begun to appear. Engineers are now faced with the need to install or retrofit load transfer in the joints to preserve the pavements. Questions associated with this decision range from the type of dowel material to dowel diameter, spacing, number of bars, placement method, and construction techniques to be used to assure reduction or elimination of faulting. Buena Vista County constructed a dowel bar retrofit project on one mile of road. The plan called for addition of the dowels (2, 3, or 4) in the outer wheel path only and surface grinding in lieu of asphalt overlay. The project included the application of elliptical- and round-shaped dowels in a rehabilitation project. Dowel material types included conventional epoxy-coated steel and fiber-reinforced polymer (FRP). This work involved the determination of relative costs in materials to be used in this type of work and performance of FRP and elliptical-shaped steel dowels in the retrofit work. The results indicate good performance from each of the bar configurations and use the results of ride and deflection testing over the research period to project the benefits that can be gained from each configuration vs. the anticipated construction costs. The reader is cautioned that this project could not relate the number of dowels required to the level of anticipated truck traffic for other roads that might be considered.

• Record URL:
  http://publications.iowa.gov/id/eprint/19989
• 
• Corporate Authors:

  Iowa State University, Ames

  Department of Civil, Construction and Environmental Engineering
  Town Engineering Building
  Ames, IA  United States  50011-3232

  Iowa Department of Transportation

  800 Lincoln Way
  Ames, IA  United States  50010
• Authors:
  • Cable, James K
  • Porter, Max L
  • Frentress, Daniel P
  • Wood, Douglas L
  • Reinert, Sybil K
  • Walker, Jason
• Publication Date: 2008-2

Language

• English

Media Info

• Media Type: Print
• Edition: Final Report
• Features: Appendices; Figures; Photos; Tables;
• Pagination: 48p

Subject/Index Terms

• TRT Terms: Benefit cost analysis; Concrete pavements; Dowel bar retrofit; Epoxy coatings; Fiber reinforced plastics; Load transfer; Retrofitting; Steel; Tie bars; Transverse joints; Truck traffic
• Geographic Terms: Iowa
• Subject Areas: Design; Highways; Maintenance and Preservation; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces; I61: Equipment and Maintenance Methods;

Filing Info

• Accession Number: 01100238
• Record Type: Publication
• Report/Paper Numbers: IHRB Project TR-520
• Files: TRIS, STATEDOT
• Created Date: May 29 2008 4:21PM