Highway US-50 Soil Stabilization in Nevada
Problem
Highway US-50, nicknamed the “Loneliest Highway in America,” is a two-lane composite rural highway stretching from California to Maryland. Pavement settlement in a section of the highway about five miles outside of Austin, NV, caused three severe diagonal fissures in the road surface to develop. The worst of these fissures measured a staggering 13 inches wide and 9 feet deep. The Nevada Department of Transportation (NDOT) needed to find a fast and permanent solution to this problem before the onset of winter.
Analysis
The engineering team at NDOT decided to pursue a pressure grouting injection program to solve the roadway fissure problem by stabilizing the underlying soil. Given the choice between a cementitious suspension grout or a polymer grout, NDOT chose to use polymer and brought URETEK on board to complete the job. The URETEK Deep Injection® (UDI) process offered several key advantages that were beneficial to this job. These included very fast application and reaction times, the use of small diameter injection tubes, and the lack of significant overburden weight. To the last point, if NDOT had chosen to use a cementitious grout, it would have added up to 189,000 pounds of overburden weight to the base while the URETEK process added only 5,400 pounds.
Solution
The URETEK crew completed this job over three days in 15°F temperatures and high wind conditions. With UDI, the soil under the 32-foot section of pavement was stabilized from the top down. By bonding the various strata together, the URETEK 486® polymer created a strong subbase to ensure the fissures would remain closed in the long term.
Result
The repair was completed before the onset of harsh winter conditions thanks to the speed of the UDI process. NDOT was very pleased with the work. NDOT Design Division’s Kathleen Weaver remarked, “I would like to take this opportunity to note the competence and professionalism of the crew. It was obvious to NDOT staff in attendance at the job site that this URETEK team was knowledgeable, conscientious, and diligent in the execution of their duties. They performed like a well-oiled machine.”
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.
