Pavement Settlement in Georgetown, Kentucky

Problem

In Georgetown, KY, the Lexus Way exit on I-75 was recently constructed to better accommodate a large auto plant. As part of the project, a box overpass was constructed for traffic to access a rest area just past the new exit. Soon after construction, settlement began to occur around the box overpass in all four lanes. Patching efforts were unsuccessful as the area continued to settle. Kentucky Transportation Cabinet began receiving more and more complaints from motorists about this area. The client needed the safety and rideability issues remediated immediately.

Analysis

A site visit and some research into the construction process confirmed URETEK’s assumptions that fill soils were likely poorly compacted. It was determined that the URETEK Deep Injection (UDI) was the best solution for KYTC. URETEK arrived at the location and used Dynamic Cone Penetrometer (DCP) testing on both the eastbound and southbound lanes to evaluate the area’s soil strength. It was determined that the EB lane only needed a correction of -4’ while the WB lane needed a correction of-8’. The goal was to fix all safety and rideability issues.

Solution

For the soil stabilization effort in Georgetown, URETEK Deep Injection® (UDI) was employed by injecting the 486 Star® polymer into the soils across all four lanes to increase soil strength enough to carry traffic loads. This both stabilized the subbase soil and tapered out the dips, restoring the safety and rideability to the Lexus Way corridor. The crews were able to save time and preserve commuter routes by keeping only one lane closed during work hours to ensure a steady traffic flow.

Result

URETEK stabilized the underlying soils and lifted the asphalt roadway back to grade without causing significant traffic closures. KYTC District 7 engineers were pleased with the results. After receiving numerous complaints from motorists prior to the procedure, they were delighted to have had none since completion. Compared to full depth replacement and repeated mill and overlay, the time of repair was greatly reduced due to the preservation of the subbase soils and the pavement. Due to this, the cost was significantly reduced. Virtually no damage was done to the pavement by using only ¾” holes to complete the UDI. After a significant soil stabilization issue, URETEK provided a safe, efficient, and cost-effective solution in just under three days.

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.