The Naval Air Station (NAS) in Corpus Christi, Texas, had an emergency problem on their hands when Runway 13L/31R settled so significantly that it prevented small aircraft operations. The whole runway had to be shut down because of these settlement issues, and NAS needed to find an immediate and long-term runway stabilization solution so that aircraft operations could resume safely. The NAS contracted URETEK to repair a section of pavement on the runway located above a drainage culvert that was exhibiting distress, and return the runway to operational status in a timely manner.
While a previous repair of the 36-inch reinforced concrete pipe storm culvert corrected leaking issues and prevented further loss of soil, it did not address the poor compaction and loss of support for the pavement system above. Additionally, Dynamic Cone Penetrometer (DCP) tests performed before the repairs indicated that soil compaction was inconsistent, meaning that injection into the soil would be more difficult than anticipated.
URETEK’s solution involved the URETEK Deep Injection® (UDI) process. For this project, injections were performed at two depths, and project supervisor Sam Hendricks and his operations team developed and employed innovative drilling and injection techniques. Despite the tendency of the holes to collapse due to the very fine sands and water found at the site, their innovations allowed the polymer to reach the areas where it was needed most.
URETEK performed long-lasting repairs in record time. Including mobilization time and four URETEK work days, the runway was back up and running in a total of only seven days. URETEK’s intervention increased the bearing capacity of the runway and filled voids under the runway to prevent future settling. URETEK stabilized the soils as far down as ten feet below the surface using the UDI process. Increased flow through leaks in the junction boxes indicated the treatment was improving the stability of the pavement system by displacing water from under the runway. The soils outside the junction boxes were stabilized after the runway treatment was completed. Following up nearly two years after project completion, no further settlement had occurred in the repaired areas.
URETEK Deep Injection® (UDI)
Widely referenced throughout our industry, UDI involves the injection of structural polymer into base and subgrade soils to increase the load bearing capacity. This is achieved by injecting the polymer through small holes drilled directly through the pavement structure to depths determined by site-specific analysis. Our URETEK 486 Star® material flows easily into voids and weak zones within the soil mass below. Through a controlled chemical reaction, the expanding polymer compacts surrounding soils and applies a controlled pressure on targeted areas of the affected pavement above. If needed, a multi-injection design plan is utilized to gently return the pavement to its original grade. The composite material quickly cures into a strong, dimensionally stable, and water-resistant geo-material, providing years of reliable service.
URETEK 486 Star®
URETEK 486 Star® polymer is a two-component, high-density, expanding thermoset polyurethane system. It was developed to be the ideal solution for under-sealing, void filling, lifting of settled pavement, stabilization and stiffening of weak soils, and for encapsulating and sealing buried infrastructure. URETEK 486 Star® is environmentally inert, non-toxic, and resists underground water erosion or weakening due to its industry-leading hydrophobic properties.