The multi-year effort to preserve RDU’s aging primary runway, 5L/23R, concluded for 2020 when the last slab of new concrete was poured on April 23.

The emergency preservation work began in 2019 and is one of the airport’s most important capital projects. Concrete on the 10,000-foot runway has deteriorated after more than three decades of use. Although it is still safe for flying, the runway requires regular removal and replacement of old concrete slabs so large international aircraft and heavy cargo planes can continue to use it.

RDU replaced 117 slabs during two 90-day phases of work in 2019. Another 108 slabs were replaced ahead of schedule in April 2020. During previous phases of the project, RDU closed the runway each night at 10 p.m. and immediately went to work demolishing, removing and then pouring new concrete in 625 square-foot slabs.

The entire process took about six hours, which left enough time for the concrete to cure before the runway reopened for international flights at 4 p.m. the following day. The recent decline in air traffic allowed RDU to close 5L/23R this April and move all commercial flights to RDU’s secondary runway.

RDU is working with the FAA to replace 5L/23R at a final estimated cost at least $350 million. A new primary runway, which will be built parallel to 5L/232R, is projected to open as soon as 2025 pending the conclusion of the environmental review process.