The Pennyrile Parkway in Hopkinsville, Kentucky, is a 71-mile road opened in 1976. A 50-foot dip developed on a section of the road where both southbound lanes settled as much as 3.5 inches. Even though a mill and overlay project had been completed in the area a few years ago, the roadway continued to settle. Looking for answers, the Kentucky Transportation Cabinet (KYTC) reached out to URETEK to take a look at the problem and hopefully suggest a solution for the ongoing settlement in the roadway.
URETEK performed Dynamic Cone Penetrometer (DCP) testing to determine the load bearing capacity of the soils below the settled road. The results of DCP testing demonstrated weak soil zones at depths of four and nine feet. With this data, URETEK decided to apply its URETEK Deep Injection® (UDI) process to stabilize the subgrade and lift the settled pavement.
UDI was employed for a minimally disruptive, zero-excavation stabilization of the subgrade. URETEK crews performed injections in a three-dimensional grid pattern to strengthen the soils down to 10 feet. The treatment area involved a work space measuring 50 feet long by 30 feet wide. KYTC personnel were concerned about traffic flow during the repairs, so the URETEK crew created a work plan that involved minimal disruption to traffic on the parkway.
URETEK supplied the process, equipment, materials, engineering staff, and experienced crews necessary to complete this job. In only 1 ½ days, URETEK crews were able to complete all work without requiring any heavy equipment or excavation. One lane remained open at all times, and traffic was able to keep flowing during the repair process. Most importantly, by treating the weakened subgrade soils and not just the surface level issue, URETEK offered the KYTC a long-term solution to their Pennyrile Parkway problem.
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.