Hillsborough County Florida is using a mix of expanding polyurethane foam and conventional cement grout as a more cost effective means of filling sinkholes. Officials say the mix uses 30 to 40% less grout adding up to a 30% cost savings. The article in the Tampa Tribune did not indicate the contractor or product name that they are using but apparently several agencies in California and other states are using the same material. Story via ASCE SmartBrief.
NCFI Polyurethanes’ TerraThane Product Line Quickly and Quietly Improving Bottom Line for North American Geotechnical and Geoenvironmental Businesses
MOUNT AIRY, NC—The distinctly American company, NCFI Polyurethanes, is known for pioneering innovative, improved, and unique uses for one of their main product offerings: polyurethane foam. Since the company’s scientists and engineers began formulating polyurethane foam back in 1967, other chemical systems companies have been saying, “wonder what they’ll come up with next?” So, it was really more of a “holy cow” moment in the 1990s when NCFI began formulating foam systems for geotechnical uses: highway and roadway repair, bridge approach repair, concrete lifting, leveling and void fill. And it’s no surprise that like all NCFI product lines, TerraThane geotechnical foam is quietly changing the way entire industries work for the better.
On June 11, 2002, a 150-foot wide and 60-foot deep sinkhole opened up in Pine Hills, Florida and came within a few feet of two 3-story appartment buildings. Geotechnical and Environmental Consultants (GEC) was contacted by the owner of the site to design emergency temporary and permanent stabilization measures to protect the buildings. The sinkhole mitigation began with a chemical stabilization of the soil using an injected sodium silicate chemical grout (incidentally, that work was performed by John N. Puder, Inc., recently acquired by Moretrench) to stabilize the sands underneath the buildings and adjacent to the sinkhole. After some GPR surveys, borings and other investigations, final sinkhole repair consisted of a 200-foot long wall omprised of interlocked 36-inch diameter steel tubular piles that extended to a depth of 50 feet. They were driven by Giken America Corp. using the press-in method which helped to avoid damage to the adjacent buildings. The entire stabilization was completed within 1-month of the initial sinkhole collapse! Click through for this fascinating video. (Photo credit Giken America Corp. by way of GEC)