Task: On one of the runways at Andrews Air Force Base, significant settlement occurred. An engineering survey revealed that the cause was leaks from drainage pipes. The soils surrounding these pipes were so weakened that the only feasible solution seemed to be a complete replacement of the panels above them.

Factors to consider: Andrews Air Force Base is home to the so‑called Air Force One, the US President’s aircraft and one of the most famous planes in the world. Therefore, a “runway freeze” followed by a work stoppage for security reasons could become a real challenge. Any repair work at airfields must be carried out at maximum speed, but for Andrews Air Force Base even greater efficiency was required – which only Uretek could provide.

Methodology: This unique process (deep soil injection according to URETEK® technology) relies on injecting a two‑component polymer material beneath the concrete surface through pre‑drilled holes. The expanding geopolymer between the soil and the slab provides an expansion ratio of 20:1 and a high lifting force, capable of levelling the runway and taxiway slabs. Uretek deep soil injection was applied at this facility as well, where injecting polymer to significant depths led to soil compaction.

Using the URETEK method, a number of tasks were solved in the shortest possible time. First, lifting the panels above the settled areas. The URETEK team was also able to restore the soils around the leaking pipes through the deep injection process. The injection locations were selected so that water from the soil was pushed back into the pipe. Sealing the joints of the leaking pipe became the next step before levelling and sealing the runway joints.

Advantages: The cost to remove and replace the problem areas would have been about $250,000, and would have required workers on site for 35 days. The Uretek repair cost half of the strategic cost and took a total of 10 days. Crews worked mostly at night, preserving traffic during peak hours and avoiding a possible “runway freeze” period.