Roller-compacted concrete and full-depth reclamation provides solution to major road in Bel Aire, Kan.

Reclaiming / Recycling Case Studies December 28, 2016
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Like many cities and rural communities, the city of Bel Aire, Kan., located just north of Wichita, is experiencing increased traffic growth both in volume and load. 45th Street is one of the main east-west roads through the city and connects two minor arterial roadways. The asphalt street was so significantly deteriorated that complete reconstruction was required. In deciding on the type of replacement method, the city wanted a pavement that would hold up to current and future traffic including school-bus traffic, have excellent long-term performance including exposure to freeze-thaw cycles, and require minimum maintenance. In addition the city was looking for a pavement solution that could be constructed quickly causing minimal traffic disruption and of course be economical.

 

The condition of the street prior to reconstruction had deteriorated beyond the depth of the surface pavement and had extended down into the base and subgrade. There were also many issues with expansive clays beneath the road. The road, which was originally a farm to market road, had been widened over time using an aggregate base and asphalt surface. Patching and asphalt overlays were the typical remedy, but the patchwork repairs could not keep up with the area growth and increased traffic. Eventually patchwork repairs were no longer a viable option and a major rehabilitation strategy was needed. In addition to a new surface pavement, stabilization of the base layer and subgrade soils would also be needed. With the intersecting developments along the road, the existing grade needed to be maintained. The design objective was to simply rebuild the road from the bottom up.

 

The original design called for complete removal of the asphalt pavement and base followed by the placement of a geogrid material overlain with an aggregate base and asphalt surface. Andale Construction, Wichita, Kan., submitted a value-engineering bid that the city accepted. The method Andale Construction proposed consisted of full-depth reclamation (FDR) with cement for the base with a roller-compacted concrete (RCC) pavement surface. This pavement section resulted in less excavation and material disposal, quicker construction time, a higher quality pavement and a lower initial as well as life-cycle cost.

 

The construction schedule consisted of only seven days start to finish for the ½-mile section of road. The first step was to mill off 3 in. of the existing 6-in. asphalt pavement. The remaining asphalt, base and subgrade were then pulverized and stabilized 10 in. deep using cement slurry in the FDR process. Using the cement slurry eliminated all dust and allowed the road to open to local traffic once the stabilization process was complete—even before the RCC surface was placed.

 

Following the FDR process, work began on placing the RCC pavement. The RCC was placed in a single 7-in.-thick layer directly on the FDR stabilized base. The surface of the RCC was made smoother using a power trowel and broom finished. One longitudinal joint was cut down the middle of the pavement and transverse joints were cut every 12 ft. The entire 2,600-ft-long by 24-ft-wide pavement was placed in one pass in a single day. Using the AASHTO 1993 design guide and the Kansas Department of Transportation’s layer coefficients, the original road had a structural number (SN) of 3.42. Following the reconstruction, the SN was increased to 5.36, resulting in a 65% increase in structural capacity. The end result was a strong durable pavement, constructed quickly at a reasonable cost that should last the community for many years to come. 

 

This project received multiple awards, winning the Kansas-Missouri ACPA Chapter Roller Compacted Concrete Pavement award and the National ACPA Pavement Gold Award in the Special Application Category. 

 

  • FDR process used to stabilize 10-in. base with cement slurry
  • 45th Street before work began
  • Milling top 3 in. of asphalt prior to FDR with cement process
  • Paver placing 7 in. RCC pavement
  • 45th Street after work complete
  • 45th Street after 2 years complete
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