Culvert Repair in Corbin, KY


In Corbin, Kentucky, on 3606 between KY 6 and Radio Tower Rd, District 11 engineers encountered pavement subsidence above two culverts about 0.25 miles apart. These dips and the problems associated with the weak surrounding soils presented both rideability and safety issues for motorists. To preserve commuter traffic flow, engineers needed a solution to salvage their weak subbase soils, so they decided to call URETEK.


URETEK arrived on location, and after some research, it was confirmed that settlement was not the result of faults in the culvert pipes but weak fill soils around them. Dynamic Cone Penetrometer (DCP) testing evaluated the depth of treatment. Low blow counts were encountered mostly to -4’ and as deep as -8’ in some locations. URETEK Deep Injection® (UDI) was proposed for the project as a quick and effective way to stabilize the underlying soils.


For the Corbin project, UDI was the perfect solution to repair the culverts and taper out the dips. URETEK crews performed the process, injecting URETEK 486 Star® polymer in a grid pattern over the dip areas. During repairs, one lane was left open while the procedure was completed in the other. Virtually no damage was done to the pavement by using only ¾” holes to complete the operation.


URETEK was able to stabilize the soils and even out the dips in the culverts. KYTC District 11 engineers were pleased with the results. Compared to full depth replacement and repeated mill and overlay, repair time was significantly reduced by leaving the subbase soils and the pavement in place. The road remained open during the whole process; work was completed in one lane while traffic flowed in the other. URETEK was able to eliminate rideability issues without halting traffic flow while providing long-term repairs that ensured the safety of motorists and the crew.

URETEK Deep Injection® (UDI)

Widely referenced throughout the 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. 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 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.



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