Paving Against the Clock: Chambers Field-NS Norfolk

Parker Wallace, Project Engineer, Branscome

The Golden Lute Award is given to the top paving project in Virginia completed the previous year and is based on the quality of materials, workmanship and complexity. In addition, subjective and objective measures are used to select the ultimate winner.

During the Mid-Atlantic Asphalt Expo and Conference in December, the 2021 Golden Lute was awarded to Branscome, Inc. for the Chambers Field at Naval Station Norfolk project.

Project Overview

The Chambers Field Runway 10-28 repair was a high-profile, fast-tracked project commissioned by the Norfolk Naval Facility, or NAVFAC Mid-Atlantic, completed between March 2021 and July 2021. It required a complete resurfacing of a 200 by 6,500 foot-long runway, with three to six feet of variable depth P401 asphalt. The project also involved upgrading the Instrument Landing System (ILS) or airfield lighting and signage, as well as environmental improvement, reverting approximately 94,000 square yards of paved surfaces to green space.

As the primary contractor, Branscome was responsible for the complete site package, including repairing cracks and other deficiencies in the existing concrete and asphalt; demolition and regrading the existing runway by way of Universal Total Station (UTS) milling; placing a surface treatment on the runway subgrade paving; pavement marking of the new runway; support for the ILS with micropile foundations; and new electrical duct banks.

The runway consisted of 39,000 tons of asphalt using three different mix designs and 176,000 square yards of milling, which varied in thickness from 3 to 8 inches. The infield area involved an additional 94,000 square yards of milling, which varied in thickness from six to 48 inches.

The schedule was the most significant concern going into this project. To support the construction effort, the Navy had to completely shut down the runway, rerouting all mission-essential air traffic operations away from one of the largest naval airports in the country. Due to this level of effort, all construction work had to be done on an accelerated schedule to reopen the runway on time. Four milling crews, two paving crews, and 70 trucks per day were required to meet the demanding schedule, which required all paving work to be completed in 12 days.

Special Considerations

Chambers Field was one of the first government-commissioned jobs that required personnel to undergo the Airfield Asphalt Certification Program to meet Unified Facilities Guide Specifications (UFGS). Branscome sent personnel to the National Center for Asphalt Technology at Auburn University to earn these certifications and hosted the Navy-led inspection of Branscome’s Hampton Asphalt lab and plant to confirm specific requirements, including accreditation by the American Association of State Highway and Transportation Officials.

Each lot’s pay factor was determined by taking the lowest computed pay factor based on either laboratory air voids, in-place density, or grade/smoothness; all while meeting strict government specifications. For example, the lab air voids pay factor was based on the mean absolute deviation of lab voids from the job mix formula. Mat cores were to be within 94–96% theoretical maximum density (TMD), with joint cores above 92.5% TMD. In addition, joints that ran along concrete had to be cored six inches away from the plain cement concrete joint and only rolled by a rubber-tired roller, requiring the same density as regular mat cores.

Surface smoothness was also essential for this project, so grades were checked at several stages throughout the paving process to keep them on target. The Branscome-produced asphalt material underwent thorough lab testing, then was verified by profilograph and other performance QC checks after paving was complete. The job included three mix designs:

  • 30,217.08 tons of P401 (¾ inch nominal maximum) virgin, 75 gyrations, that required PG 76-22 liquid. This design also had a very tight specification on coarse aggregate, requiring specialized stone matrix asphalt from a different quarry (which also added to logistical and planning issues). This mix design was tested over 13 lots, with 60 samples. Some days required as many as six samples to keep up with production. In addition, 126 joint/mat cores were cut and weighed out by a third-party testing firm. The asphalt content of this mix was kept to a 0.12 standard deviation throughout the project.
  • 3,144.94 tons of P403 (⅜ inch nominal) 30% reclaimed asphalt pavement, 75 gyrations, PG 70-22 liquid. This mix design was tested in two lots, resulting in seven samples, with 19 joint/mat cores cut.
  • 6,291 tons of assorted Virginia Department of Transportation (VDOT) 9.5A mix, used for scratch courses or roadways around the runway. This mix was produced and tested under VDOT specifications.

Not only was this project fast-paced, but it also required rigorous quality control checks throughout the production process. Every longitudinal joint had to be saw cut and cleaned before placing the adjacent lane, and each concrete tie-in was paved parallel to the concrete surface and compacted with a special rubber tire roller. Branscome utilized a tandem paving operation to reduce the number of longitudinal joints that had to be saw cut and improve the overall joint quality and appearance. Both milling and paving were performed with UTS machine control to meet the variable grades and precise tolerances on the final elevation of +/- 0.03 feet.

The quality control (QC) data demonstrated that all 12 lanes exceeded target smoothness criteria (seven inch/mile) with an overall average reading of 0.77 inch/mile and a single maximum reading of 1.78 inch/mile. After paving was complete, the asphalt was required to cure for 30 days before being grooved and striped.

Another significant challenge was related to updated contract agreements and change orders with limited deadline extensions. During the milling phase, the team encountered an unanticipated concrete subgrade beneath the runway surface that required several inches of milling to meet final grades. This required Branscome’s team to modify the milling equipment before proceeding.

After completing profile milling, Branscome received a redesigned runway profile to accommodate elevation issues on the runway ILS unaccounted for in the original design. This change added over 5,000 tons of production paving to the scope of work, including a UTS-paved leveling course. The scope of paving work also expanded to include shoulders and taxiways, increasing the scope of the concrete joint sealant on the concrete runway overruns and other miscellaneous work. These updates forced the team to completely reschedule the paving sequence of work to maximize daily productions while working concurrently through redesign. In addition, the final paving sequence was designed to eliminate all transverse joints except those at concrete tie-ins to improve the surface smoothness of the final product.

Branscome worked efficiently through these conditions and recycled over 90% of the waste material on the project, which diverted over 100,000 tons of concrete, asphalt, and soils from landfills. The mile-long runway was ready for military aircraft operations on July 19, 2021.

Chambers Field Runway-NS Norfolk