LOW-SEVERITY
TRANSVERE CRACKS
If you have low-severity transverse cracks while aggregate interlock is still intact, you need to perform:
Dowel Bar Retrofit
Dowel bar retrofit (DBR) is a concrete pavement preservation (CPP) tool that restores load transfer across transverse joints and cracks by installing dowel bars to link adjoining slabs. Mechanical load transfer devices such as round steel dowel bars prevent differential vertical movement of the slabs at the joints and cracks, thereby eliminating the formation of faults or stepoffs. Used in conjunction with other CPP practices, such as diamond grinding, DBR can return a concrete roadway to a structurally sound, smooth condition that can exceed the smoothness and noise values attained at the time of construction.
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To perform DBR, slots are cut using diamond saw blades. The slots are placed on 1-foot centers, centered over the transverse joint or crack and parallel to the centerline with three or four slots per wheel path. Dowel bar assemblies are placed into cleaned slots then backfilled, patched and diamond ground to provide a safe, smooth and quiet surface.
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Where to consider DBR:
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Pavements that exhibit a reduction in load transfer.
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Joint and crack faulting between 1/8 to 3/4 inch.
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Transverse cracks that are reasonably tight with minimal spalling.
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Pavements that were constructed as non-doweled jointed pavements, which can have DBR applied to prevent future faulting.
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If aggregate interlock is lost, refer to the cracked slab section.
Resources
Evaluation of Dowel Bar Retrofits for Local Road Pavements
The Buena Vista County staff developed a construction project to retrofit the dowels in the joints and grind the surface of the test pavement. The contract included items for the preparation and the installation of dowels in each of the transverse joints in the pavement. After a careful analysis of the dowel bar retrofit (DBR) sections, the conclusion was made that FRP bars maintain a better IRI. However, this comes at a higher cost.
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Technical Info
City/Municipal
Dowel Bar Retrofit
Structural/Material Issues
Concrete Repair Best Practices
Concrete pavement restoration (CPR) techniques have gained greater national significance as DOT agencies attempt to further extend infrastructure service lives prior to required major rehabilitation or reconstruction. This report consolidates best practice case studies for six CPR techniques: cross stitching, dowel bar retrofit, diamond grinding, full depth repair, partial depth repair and slab stabilization.
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City/Municipal, Highway
Concrete Pavement Preservation and Restoration, Diamond Grinding, Dowel Bar Retrofit, Full & Partial Depth Repair, Joint and Crack Resealing
Structural/Material Issues
Dowel Bar Retrofit - Do's and Don'ts
Detailed guidelines for the construction and inspection of dowel bar retrofit (DBR) projects are provided in this Washington State Department of Transportation (WSDOT) report. Essential steps include cutting slots, removing existing concrete, cleaning slots, applying silicone sealant, placing dowel bars, and patching with concrete material. The study emphasizes the importance of proper dowel bar placement tolerances and the use of diamond grinding to restore pavement smoothness. Additionally, managing slurry is highlighted to ensure environmental compliance.
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Technical Info
City/Municipal, Highway
Dowel Bar Retrofit
Structural/Material Issues
MoDOT Tech Brief: Dowel Bar Retrofit
This brief summarizes the use of dowel bar retrofit (DBR) technology to improve load transfer efficiency (LTE) in existing concrete pavements. It highlights Washington State's extensive experience with DBR, which has shown to increase LTE, significantly preventing future joint and crack faulting after diamond grinding. Washington's DBR projects have successfully extended pavement life by up to 22 years, showcasing DBR's effectiveness as a long-term pavement preservation technique.
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Technical Info
Highway
Dowel Bar Retrofit
Structural/Material Issues
Long Term Performance of Dowel Bar Retrofit in Washington State
Washington State Department of Transportation (WSDOT) initiated its first full-scale dowel bar retrofit (DBR) project for the repair of a severely faulted concrete pavement. DBR application, in conjunction with panel replacements and diamond grinding, has proven to be an effective rehabilitation treatment for faulted concrete pavements.
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Highway
Dowel Bar Retrofit
Structural/Material Issues
FHWA Pavement Preservation Checklist Series: Dowel Bar Retrofit
This checklist for dowel bar retrofit for portland cement concrete is one in a series created to guide state and local highway preservation/maintenance and inspection staff on the use of innovative pavement preservation techniques. FHWA uses its partnerships with different pavement preservation organizations including American Association of State Highway and Transportation Officials, and state and local transportation agencies to promote pavement preservation.
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Technical Info
City/Municipal, Highway, Industrial
Dowel Bar Retrofit
Structural/Material Issues