Better Roads

October 2013

Better Roads Digital Magazine

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HighwayContractor overall quality program. "The contractor had three separate paving operations going at the same time. We had 24 qualitycontrol staff on the project during the extended 55-hour weekend closures. The biggest logistical challenge we had from a quality standpoint was conducting all of the inspections and ensuring the materials met the stringent long-life pavement quality requirements in real-time as the project was being built." The I-710 rehabilitation is actually a series of projects stretching several years that could ultimately cost $650 million when the final tally is complete. The work stretches northward from the port, beyond the I-405 intersection to downtown Los Angeles and connecting with busy Interstate 5 and 10. Even among traffic-jaded Angelenos, the reviews have been positive. "The sensation is palpable, if not slightly remarkable," the Los Angeles Times gushed in a 2009 profile that appeared on Page 1. "There, you are hurtling in the No. 3 lane on the Long Beach Freeway. Your car is rattling, your tailbone jumping to the rhythm of a concrete washboard abused by years of heavy trucks and piecemeal repairs. Then it happens, between the 105 and Rosecrans. You hit a bump, and suddenly your tires purr, your coffee settles in its cup and the radio reception seems more crisp. You may not know why – it is the nature of freeways that we seldom consider their mechanics – but you are now experiencing the I-710 long-life pavement project, as Caltrans calls it." To call these projects big is an understatement, and the scrutiny they received was even bigger. Phase 1 included full-depth construction (with a rich bottom layer) and HMA overlays of cracked and seated (C&S) of old Portland cement concrete (PCC) pavements. The performance of Phase 1 is studied on an annual basis (including annual deflection testing). An extensive description of the Phase 1 design and construction can be found in the Journal of the Association of Asphalt Paving Technologists (AAPT); Volume 70 (2001) paper by Carl Monismith, Fenella Long and John Harvey titled, "The Interstate 710 Rehabilitation: Mix and Structural Section Design, Construction Specifications." Subsequent work of the 710 LLAP projects was also done on a grand scale. Phase II of the I-710 started in July of 2007 and was scheduled to be complete in 2013. It involves $144 million worth of construction work, of which the paving contract with All American Asphalt amounts to $52.5 million, and more than 400,000 tons of HMA of various types. 20 Here is a look at some of the many lessons the Caltrans team learned on the I-710 project: • Pre-bid conference should be mandatory for all potential bidders. • For projects of this importance, a partnering meeting at the outset should be mandatory. • For new test procedures in the special provisions, ensure all involved groups test and analyze resulting data the same way. • Human resources during the process were "stretched," so a number in succession 3 to 5 maximum with 1 or 2 weekends in between is recommended. • Contractor should select closure locations. • Input from meteorologists is important for contractor for weather forecasting for 55-hour closures. • Contingency planning is extremely important; in this case, aggregate supply for working platform was locally available. The asphalt binders used on the I-710 project preceded the implementation of the PG-grading system in California. As such, PBA-6a, a heavy polymer-modified asphalt (PMA), was used in the top 3 inches, and AR-8000 was used in the other layers including the 3-inch-thick "rich bottom" layer. The variability in structural pavement thickness is concentrated in the varying thickness of the middle layer(s). For overlays of October 2013 Better Roads HighwayContractor_BR1013.indd 20 9/30/13 2:09 PM

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