Protecting concrete usually means shielding it from the elements of nature or from harsh manmade chemicals. But it’s not just concrete that needs such protection. Corrugated metal pipe, steel surfaces, material hoppers, rail cars and masonry all can come in contact with corrosive or abrasive materials or harsh conditions.
The geotechnical needs of DOTs and other agencies responsible for roads and bridges are vast. Issues include: Culvert repair Soil stabilization Void filling Concrete slab lifting Sinkhole remediation Slope control Slough control in tunneling
The USDA, U.S. Geological Survey Department, U.S. Fish & Wildlife department and the Wetland Reserve Program are working to restore wetland hydrology. In this massive effort that spans several states, the goal was to remove the drain tiles with as little ecological impact as possible.
To dig up the tiles would cause a great deal of environmental impact. Even with the most careful excavation, the soil would not return to the native soil state. This method would also be costly when factoring in both time and equipment operational costs. With that in mind, the decision was made to leave the tiles in place and to seal them off.
Drain tiles can run from a few hundred feet to over 1000 feet in length. For plugging with urethane, access points were needed approximately every 300 feet. A pull wire was used to pull the polyurethane mixing manifold from one access point to the next, allowing a full distribution of the foam throughout the tile length. Workers injected Prime Flex 985 LX 20 foam into the pipe to seal it off. This was done using the FlowMaster, a pump manufactured by Prime Resins, which is ideally suited for pumping Prime Resins’ dual-component polyurethane resins. Some sections were filled solid, while others used intermittent shots every 15 to 20 feet.
Prime Flex 985 LX 20 is a two-component, closed cell polyurethane foam that expands up to 20 times its volume, thus completely sealing the tile pipe and even pushes through crack and joints, adhering to the surrounding soil and filling voids between the outside of the tile pipe and surrounding soil. The product is NSF/ANSI Standard 61 approved for contact with potable water and fully expands (cures) within minutes, even if water is in the tile. One 10-gallon unit of Prime Flex 985 LX20 can be used to fill approximately 130 linear feet of pipe.
The website for Project Muse has an even more detailed report regarding these efforts that can be found here.