State Highway Culvert Repair in Kentucky

Problem

In Elizabethtown, Kentucky, two dips formed on both northbound lanes above a large culvert on KY 361. The dip approaching the culvert was three inches, and the dip on the departure side was five inches. The culvert was 12 feet in diameter, located 15 feet below grade. The culvert was only 10 years old and had already experienced significantly more settlement than KYTC had anticipated, and with the pavement dips representing a growing safety hazard for drivers, state officials called URETEK.

Analysis

URETEK crews arrived at the site and began conducting dynamic cone penetrometer (DCP) testing in two locations. These tests showed weak and wet soils extending beyond the 12 feet of cover. A recent culvert inspection report indicated no signs of leakage anywhere. After consultation with state officials, URETEK proposed an application of URETEK Deep Injection® (UDI) to stabilize the weak soils, mitigate the impact of moisture in the subgrade, and return the roadway back to a level and safe condition.

Solution

URETEK crews prepared the site and laid out the injection plan. Holes were drilled through the pavement and tubing was installed to adequately treat the weak soils below. High-density polymer was injected at depths determined by DCP testing to stabilize and strengthen the subbase soils. As the UDI application progressed, crews carefully lifted the roadway to alleviate the dips and return each lane to its originally designed grade. URETEK crews completed one lane at a time, keeping the other lane open for traffic.

Result

Upon completion of the UDI application, KYTC personnel were happy with the results. The KY 361 subbase was strengthened and stabilized, while traffic moved smoothly above. Full access to all northbound lanes was available immediately after the URETEK crew left the site, and the project was completed on time with no significant interruptions to the normal flow of traffic.

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.

Culvert Repair
Culvert Project
Crews worked on one lane at a time on the KY 361 culvert project
Culvert Repair
URETEK crews install injection tubes above the culvert