Terrell Materials Corporation completed the construction of one of our nation’s largest commercial runways in October of 2013.  The Chicago-based joint venture of Walsh Construction/Terrell Materials/ TJ Lambrecht, constructed this project flawlessly with uninterrupted service in one of the world busiest airports, Chicago O’Hare International.  After the commissioning of O’Hare’s newest runway, our team was recognized by the City of Chicago Department of Aviation Contractor of the Year Award.  This was the first time an African American owned construction firm was recognized for this award for the construction of a runway.

The new runway was built to handle what are called Group VI aircraft—the largest type currently being designed and constructed—which include the Airbus A-380 and Boeing 747-8. Terrell Materials manufactured over 750,000 cubic yards of portland cement concrete pavement (PCC) for the entire 10C-28C runway.  Pavement materials and thicknesses for the runway were carefully determined to ensure that the new runway would meet strength requirements while remaining cost effective for the airport.
A key aspect of the runway design was attaining the proper pavement thickness to withstand landings by the larger aircraft. Runway 10C-28C was designed by forecasting the types of aircraft expected to travel through O’Hare, followed by determining their needs on the basis of weight, turning radii, takeoff and landing frequencies, and landing gear configurations.  Engineers and planners developed the pavement length, thickness, and location and type of exit taxiways by applying these parameters to specific site conditions.  A detailed design was developed understanding soil conditions, water impact, and existing airfield restrictions.  With extremely tight tolerances required by the FAA, Chicago Department of Aviation and the DOT, Terrell Materials delivered.   Averaging approximately 3,000 cubic yards per pour day, Terrell’s quality was unprecedented.
  
The pavement layers were determined in part by the ability of the subgrade to support the distributed loads.  The design of the runway called for a lime-stabilized subgrade that mixes the top 12 in. of clay at the site with lime and water, which provides high soil strength and results in a significant reduction in the required pavement thicknesses.   A six inch section of asphalt-treated permeable base (ATPB) was placed in one to two layers atop the stabilized subgrade by our subcontractor.  This layer was compacted at a specific temperature that will enable voids in the material to remain and will allow for drainage.  An asphalt binder layer of blended aggregate, based on Illinois Department of Transportation specifications, formed the next six inch layer. This is expected to produce fewer air voids than an ATPB and was used in lieu of portland cement concrete pavement (PCC) to reduce cost. 
PCC, however, does comprise the top layer of the pavement, but—due to the lime-stabilized subgrade—is only 18 in. thick instead of 21 in. thick, the thickness traditionally used at O’Hare.  This saved money on labor and material when it came to the thickness of concrete.  The thicker you go in the pavement, the longer construction would be.
 
The pavement was placed in 20 by 20 foot sections connected by load-transfer dowel bars.  The top pavement thicknesses [is designed] to support the aircraft traffic for 20 years of use before requiring major rehabilitation.  Certain portions of the runway and taxiway surfaces will be grooved for maximum braking resistance and surface drainage. 

Federal Aviation Administration requirements were met to mitigate the environmental impact of the runway construction on the surrounding communities. Utilization of tier two and three equipment were operated throughout the project.  Terrell Materials also recycled over 500,000 tons of existing taxiway and runway.  These practices on this project have helped keep the O’Hare Modernization Project a world leader in green construction and sustainability.