CONCRETE PAVEMENT PROGRESS 16 WWW.ACPA.ORG have an average of approximately 2,600 vehicles stopping at southbound rest area each day and 3,000 northbound. Thirty-four to thirty-eight percent of these vehicles will be trucks or buses,” said Caltrans Project Manager Navraj Jammu. At the project’s outset, more than 6,500 cubic yards of soil were moved while re-grading the site, and the existing northbound and southbound comfort station buildings were demolished. Those buildings were replaced with a water treatment facility, comfort stations and vending buildings on both northbound and southbound sides of the highway, and structures for the use by maintenance crews. A wastewater treatment facility was also built on the site. Concrete was chosen for the project’s pavement, as it offers a long life—40 years or longer—while requiring little or no maintenance. More than 180,000 cubic feet of concrete (90,000 on each side of the highway) were installed to serve as parking for trucks and cars, along with an additional 40 feet of concrete pavement that created the SRRAs on- and off-ramps. The car parking areas are constructed of 9-inch-thick jointed plain concrete pavement (JPCP) and truck parking areas are constructed of 12-inch-thick JPCP. Steel dowels were inserted to help distribute loads. The original asphalt pavement was removed, ground up and recycled as base material for the new pavement. “Given our sustainability goals, using hot mix asphalt didn’t fit,” said Jefferson Birrell, Landscape Associate at Caltrans. “We believe this rest area will be in place for a long time, and concrete pavement will last.” Rigid and durable, concrete pavement is better suited to withstand the heavy I-5 truck traffic. “Improving the structural capacity of the parking areas was a goal of this project,” said Michael Smith, Infrastructure Solutions Manager at CEMEX, the cement supplier for the project. “Because concrete creates a rigid pavement and not a flexible one, it won’t rut. Furthermore, the point load of a parked vehicle (and of starting and stopping vehicles) is greater than the load of a moving vehicle, so rigid pavement helps spread out that load. By distributing the load instead of concentrating it, we avoid having it penetrate into the subgrade, which can happen with flexible pavements. Those heavy, concentrated loads on flexible pavement can sometimes even penetrate into the base.” continued from page 15 Fig. 2: Aerial shots of the John “Chuck” Erreca Rest Area Replacement Project on I-5 in California, about 1,000 feet north of the Merced-Fresno county line, show the construction of long-lived concrete pavement. RETHINKING AND REPAVING
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