April 16th, 2015
MOUNT AIRY, NC—Highways around Houston, TX, known as one the nation’s worst cities for traffic behind Los Angeles, D.C., and Atlanta, need constant repair, but can’t be closed while the work is done. Nortex Concrete Lift and Stabilization, Inc., a Ft. Worth, TX company, recently completed a whirlwind
repair project on one of the city’s busiest corridors in the NE quadrant where I-10, 610 Loop, I-59, and I-69 feed millions of cars daily to, from, and around Harris County.
Normal groundwater erosion beneath the highways causes the concrete highway slabs to drop, roadway depressions, uneven bridge approaches, and uneven joints that make driving bumpy and uncomfortable, dangerous, and causes severe wear and tear on automobiles.
To make the repairs, the Texas Department of Transportation, TXDOT, brought in Nortex. The company carefully planned out the repairs for the half million pound project, and sent out four crews each with it’s own box truck rig to use a relatively new technology called “foamjacking.” Foamjacking uses high-density polyurethane foam to fill the subterranean voids, and lift the concrete slabs to proper level. “We’ve been lifting and stabilizing roadways with polyurethane foam since we got into the business back in 2003,” says Casey Derosa, asst. gen. mgr. of Nortex. “It’s a far superior method versus the old way of mudjacking.” Mudjacking is a ubiquitous term for a mix of mud, sand, cement, crushed limestone, and water hydraulically pumped into large holes drilled into the concrete slabs to fill voids and level the slabs. Mudjacking uses more and much larger equipment, and requires larger holes to be drilled. It typically requires the roadway to be closed much longer than foamjacking, and takes more time to
According to Derosa, Nortex started in January working to complete the 150 plus location project. They went about standard operations by drilling 5/8-inch holes in the concrete slabs and pumping TerraThane polyurethane foam made by the US company, NCFI Polyurethanes, into the voids, filling then lifting the slabs to proper level. On some locations the slabs were lifted as much as eight inches to ensure the highway was level and a smooth driving surface.
“We worked at night closing two-to-three lanes of the five-to-six lane highways to try to keep traffic moving and cause as little inconvenience as we could,” says Derosa. “We used our large gang drills with attached towable air compressors to drill the small holes then followed behind with the pumping equipment to deliver about 10,000 pounds of TerraThane foam per night. It was done over such a wide geographic scale—Conroe and The Woodlands down to Galveston County—it was not uncommon for the project manager to drive 100 miles a night overseeing the crews.”
Derosa says he used TerraThane because they’ve worked with NCFI Polyurethanes’ Geotechnical Division on formulations since 2003. “We love the specialized TerraThane material. It’s a four-pound foam system with very high compression strength, ideal cell structure, and low tolerance for water absorption. Day in and day out, it’s consistently the best product on the market.” Derosa points out that the State of Louisiana, with which they often work, requires geotechnical polyurethane foam be tested every 20,000 pounds pumped, and says TerraThane has “never failed the test for density, compression strength, and cell structure. Not once.”
When asked what advantage TerraThane gives Nortex over other products, Derosa says, “It’s why we’re able to do more with less poundage. State DOTs are looking for products that meet or exceed expectations and this product certainly does that. We never worry when we use TerraThane. We trust the consistency and quality of each set we buy and use. NCFI has proven to be a great partner in this growing business. “TXDOT is pleased with our operation, and the repairs. They couldn’t have asked
for a better solution, or product to do the highly specialized job.”