Silicone joint sealants from Dow Corning Corp. were selected for use in the reconstruction of the primary runway at Andrews Air Force Base to provide a performance seal for the concrete joints. Also referred to as Joint Base Andrews, the base operates the only military runway within the National Capital Region and supports the presidential airlift mission (Air Force One), aeromedical evacuation flights, and contingency response scenarios.
The west runway—one of just two at the base—was originally built in 1960 with an expected 25-year lifespan. Not surprisingly, by 2010 it was failing and needed to be completely replaced. The construction project, which began in late summer 2010, involved replacing 11,300 feet of the 200-foot-wide concrete runway.
On the Fast Track
Because Joint Base Andrews only has two active runways, replacing the west runway needed to be done as quickly as possible to minimize the disruption of operations. The materials used for constructing the runway also had to be easy to work with under a variety of weather conditions.
As one-component, cold-applied materials with a constant consistency over a wide temperature range, 888 Silicone Joint Sealant and 890-SL Silicone Joint Sealant are ready to be used straight out of the container and can be applied by hand or with a pump, without the need to prime the concrete.
Making a Quality Connection
The joints between the large airport runway slabs are specially designed to move within the silicone’s movement capabilities (+100/-50%) due to concrete thermal expansion cycles and as opposing slabs deflect during an aircraft takeoff or landing. These joint sealants meet the Federal Aviation Administration (FAA) P-605 silicone sealant requirements for use in airfield applications, and 890-SL is designed for use in concrete-to-asphalt joints such as the shoulder joints of runways.
The silicone sealants must be stored properly and meet quality standards when they arrive on the jobsite. Kenseal Construction Products, the Dow Corning distributor for the project, knows the standards and helps run field quality checks along with the paving contractor.
“All of the material we received onsite was in prime condition for use. There was no wastage or spoilage, which can happen if the sealant is stored improperly or kept for too long,” says Rob Nielsen of Pavement Contracting Services, the company that completed the installation.