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|Federal Highway Administration > Publications > Focus > October 1998 > Los Angeles County Counts on Superpave Mix To Handle Overloaded Trucks|
|October 1998||Publication Number: FHWA-SA-98-026|
Los Angeles County Counts on Superpave Mix To Handle Overloaded Trucks
The $2 billion Alameda Corridor project in the Los Angeles area poses a huge challenge for the State and local highway agencies involved in the project–namely, to build a pavement designed to carry 41 million equivalent single-axle loads (ESALs)* over 20 years, a traffic load many times higher than most highway projects.
The Alameda Corridor project will increase capacity and reduce congestion on the truck and rail links to the neighboring ports of Los Angeles and Long Beach, the largest port complex in the country. This complex handles 25 percent of all U.S. imports and exports. The Alameda Corridor project will consolidate the rail lines to the port, remove 200 at-grade rail crossings that delay car and truck traffic, and expand and reconstruct 35.5 km (22 mi) of Alameda Street, the main highway to the port complex.
The reconstructed and expanded Alameda Street will carry punishing traffic volumes and loads, including trucks hauling cargo containers that are much heavier than those allowed on most highways. The port complex does not have enough room to unpack containers arriving on cargo ships. Overweight cargo containers are therefore trucked, via Alameda Street, to the rail yard in downtown Los Angeles, where they are repacked into smaller containers before being loaded on trucks and rail cars for shipment to destinations across the country. The California Department of Transportation (DOT) and the other agencies involved in the project set the design traffic load extremely high to ensure that the pavement could handle these extra-heavy trucks. The local highway agencies involved in the project and their industry partners were allowed to select their own design for the section of Alameda Street under their jurisdiction, provided it met the design life requirements. The California DOT reviewed their decisions and approved the pavement structural and mix designs.
For the Los Angeles Department of Public Works (DPW), which is responsible for widening 9.7 km (6 mi) of Alameda Street from four to six lanes, the cost-effective answer was the Superpave system. "Many people recommended portland cement concrete to resist rutting," says Frank Lancaster, materials engineer for the DPW. "The asphalt industry suggested that we try the Superpave system." The DPW decided to allow contractors to bid the job as either a portland cement concrete project or a Superpave project. Every single contractor bid the job as a Superpave project.
"As an industry, we have been encouraging highway agencies in California to implement the Superpave system," says Paul Rademacher of the California Asphalt Paving Association. "We think the technology is going to add a lot to the performance of asphalt pavements, and will be compatible with California's huge range of climates."
The DPW's Lancaster says the use of a Superpave pavement will mean considerable savings on the county's share of the project. "A concrete pavement could have cost $1 million more than a Superpave pavement," he says, adding considerably to the $17 million cost of the DPW's portion of the Alameda Corridor project.
The DPW's Superpave mix will use a PG70-10 binder and a 19-mm aggregate gradation. The pavement will consist of a 48-cm (19-in) surface course on a 10-cm (4-in) base course.
The DPW has already used Superpave mixes on two pavements–a test section on a residential street and a larger project on a major highway in the San Fernando Valley. Lancaster says both pavements are performing well, backing up the decision to build a Superpave pavement on Alameda Street: "We had record rain last winter, and this summer has been very hot. They've been through both extremes and are doing fine."
Construction of the Alameda Corridor project began last year and is expected to be completed by 2000. Los Angeles County will begin building its section of the project in April 1999.
For more information, contact Frank Lancaster, Los Angeles DPW (phone: 626-458-3136; fax: 626-458-4913).
For more information on the Alameda Corridor project, contact Manuel Hernandez at the Alameda Corridor Transportation Authority, 310-816-0460 (fax: 310-816-0464).
For more information on the Superpave system, contact John D'Angelo at FHWA (phone: 202-366-0121; fax: 202-366-7909; email: email@example.com).
* An ESAL is equivalent to an 80-kN (18,000-lb) load applied to the pavement by two sets of dual tires on a single axle.
The Los Angeles Department of Public Works is turning to the Superpave mix design system to widen 9.7 km (6 mi) of Alameda Street, the main highway to the ports of Los Angeles and Long Beach.
United States Department of Transportation - Federal Highway Administration