“Temporary” Emergency Repair Turns Permanent in Texas

Problem

A roadway area measuring approximately 40 feet by 12 feet cracked and dropped about 1.5 inches in the main lanes of US 81 in Decatur, Texas. The ends of this dropped section “pumped” as traffic crossed over, and the pumping caused the ends to break apart. To make matters worse, the problem developed shortly before Memorial Day weekend when heavy traffic was expected on the road. With the holiday looming near, the Texas Department of Transportation (TXDOT) wanted to temporarily stabilize the area until enough lane closure time could be arranged to perform a full-depth repair of the pavement, base, and subbase. TXDOT called URETEK on the Wednesday before Memorial Day requesting onsite work to begin that Friday.

Analysis

URETEK’s Dynamic Cone Penetrometer (DCP) tests showed extremely weak soils down to 13 feet, leading URETEK to conclude that this lack of support caused the settlement and cracking of the pavement. The failing section of pavement had previously been injected twice by a competitor in the two years prior, but they used an old style of injection where materials were injected directly beneath the pavement.

Solution

TXDOT issued a purchase order to URETEK using the Texas Smart Buy Procurement System to utilize the URETEK Deep Injection® (UDI) process. With this process, URETEK injected its strong yet lightweight, expansive structural polymer into the soils beneath the pavement. The URETEK crew arrived on the Friday before Memorial Day weekend and successfully stabilized the weak soils by injecting at multiple depths. URETEK continued injection into the soils to lift the sunken pavement area to the proper grade. URETEK stabilized and re-aligned a total of three panels. The entire repair was accomplished in one day allowing for safe travel over the busy Memorial Day weekend.

Result

URETEK stabilized the weak subbase/subgrade and lifted the panels to grade, significantly extending the service life of the roadway. The only further repair needed by TXDOT was to cut out and replace the small pieces of broken concrete. While this project was envisioned by TXDOT as a temporary emergency repair, URETEK exceeded the client’s expectations by delivering a long-term fix in a very short amount of time. The foundation soils were strengthened to sufficiently support the load, the pavement life was extended due to restoration of the slab support, URETEK provided a two-year unconditional warranty against settlement, and all this was achieved in only one day of work with immediate roadway reopening.

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.