High Performance Concrete Pavements Project Summary
Chapter 34. Washington 1 (SR 395, Kennewick)
Traditionally, reconstruction of urban intersections with portland cement concrete pavement (PCCP) requires several weeks and complex traffic management plans. However, with accelerated paving construction techniques, concrete can meet opening strengths in less than 12 hours, providing quick public access to a high-quality, long-lasting pavement. In the fall of 2000, the Washington State Department of Transportation (WSDOT) reconstructed an asphalt concrete (AC) intersection with PCC over a weekend in a 70-hour period. The intersection is located at SR 395 and West Kennewick Avenue in the City of Kennewick, Washington (see Figure 92). The successful completion of this project demonstrates that concrete can be used successfully for the rapid reconstruction of urban intersections.
Figure 92. Location of WA 1 project.
The goal of this project is to develop a body of knowledge and tools for accelerated reconstruction of urban intersections using PCC. To achieve this goal, three classes of activities were investigated: methods to accelerate the rate of concrete strength gain, methods to minimize the construction time, and traffic control strategies to minimize user delay (Nemati et al. 2003).
Project Design and Layout
Before reconstruction, the HMA pavement exhibited severe rutting, as much as 50.8 to 101.6 mm (2 to 4 in.) (Nemati et al. 2003). Traffic volume passing through the intersection is as high as 30,000 vpd, including 20 percent heavy trucks (Nemati et al. 2003). A 3-day weekend closure, beginning on Thursday evening, was adopted for the intersection reconstruction. Efforts were focused on the following aspects:
Public Relations and Traffic Management
Many individuals, especially business owners in the affected areas, were contacted personally by WSDOT personnel. Pre-construction meetings were held with the City council and the public to encourage active involvement of all the affected parties. The media was utilized to alert the public to the upcoming construction and to keep them up to date on the schedule. A multistaged traffic detour plan was implemented that provided local access, access to commercial sites, and special routes for heavy trucks passing through the area. These activities were aimed at making the closures as organized and painless as possible for the public.
Concrete Mixture Properties
For this project, the concrete mix design was critical in maintaining the accelerated schedule. ASTM C 150 Type III portland cement was used to provide rapid strength gain. Table 52 shows the concrete mix design used in this project, while Table 53 shows the characteristics of the concrete delivered to the site (Nemati et al. 2003). Figure 93 shows the strength-maturity relationship that was developed for the specific concrete mixture used in the intersection reconstruction (Nemati et al. 2003). According to WSDOT requirements, a minimum concrete compressive strength of 17,236.9 kPa (2,500 lbf/in2) must be achieved in order for the intersection to be opened to traffic. Figure 93 indicates that this mixture is capable of reaching the opening strength approximately 8 hours after placement.
|Cement (lbs/yd3)||ASTM C150 Type III||705|
|Aggregate (lbs/yd3)||1.5 in.||940|
|0.375-in. Pea Gravel||140|
|Air-entraining admixture (oz/yd3)||ASTM C260||11|
|Water-reducing admixture (oz/yd3)||ASTM C494||30.3|
|Set-retarding admixture (oz/yd3)||ASTM C494 / Delvo||17.6|
|Air content||6.3 percent|
|Unit weight||149.8 lb/ft3|
|Concrete temperature||85 °F|
|Air temperature||82 °F|
Figure 93. Strength-time relationship developed for WA 1 project.
The contractor prepared and executed an hourly progress schedule during the intersection closure. Figure 94 shows the contractor's critical path method schedule (Nemati et al. 2003). The approach legs were rebuilt in the days prior to the complete intersection closure. A rotomill was used to remove the existing pavement and base at the intersection to a depth of 304.8 mm (12 in.), which was accomplished in a single pass. Concrete was placed in alternate sections, and then the sides of the newly placed pavements acted as forms for the interim sections. In this way, a significant amount of time was saved by not erecting and removing side forms for the interim sections.
Figure 94. Contractor's critical path method schedule for WA 1 project.
In this project, liquid curing compounds meeting ASTM C309 requirements were applied to the surface and exposed edges of the concrete pavement at a rate of one gallon per 13.9 m2 (150 ft2). The sawcutting at the intersection typically began within 6 hours of concrete placement. After sawing, the joints were sealed with a hot-poured asphaltic material.
Maturity meters were used in this project to monitor the strength gain in the concrete and determine the appropriate time for stripping forms and opening the pavement to traffic. The intersection was opened to traffic on Sunday between 4:00 p.m. and 6:00 p.m., well ahead of the originally scheduled 6:00 a.m. Monday morning opening.
The reconstruction of the intersection at SR 395 and Kennewick Avenue using accelerated construction techniques and complete weekend closure was completed successfully. The intersection was opened to traffic 16 hours ahead of the scheduled opening time. The breakdown of the time actually spent on each activity during the reconstruction is shown in Figure 95 (Nemati et al. 2003). As a result of the traffic control and public relation management, complaints from the public were reduced by over 70 percent compared to a project constructed 2 years before (Nemati et al. 2003). The unit price for reconstruction of the intersection at SR 395 and Kennewick Avenue is 168.26/m 2 ($15.58/ft 2) (Nemati et al, 2003).
Figure 95. Breakdown of time consumed by each construction activity on WA 1 project.
Points of Contact
Kamran M. Nemati
University of Washington
P.O. Box 95233
Seattle, Washington 98145-2233
Jeff S. Uhlmeyer
Linda M. Pierce
Washington State Department of Transportation
P.O. Box 47365
Olympia, WA 98504-7365
Nemati, K. M., J. S. Uhlmeyer, L. M. Pierce, and J. R. Powell. 2003. Accelerated Construction of Urban Intersections with Portland Cement Concrete Pavement (PCCP). Final Report. Federal Highway Administration, Washington, DC.