Punctured underground utility lines and other accidental pipe damage are daily occurrences in the United States. Construction crews are never happy to discover they’ve disrupted a line or miscalculated its location. Such repairs are a huge expense each year, impacting municipalities, utility organizations and construction companies.
Many of the nation’s gas utility lines are made of a type of plastic called polyethylene, similar to the material used in milk jugs. This plastic is durable but cannot be detected underground by the tools of most utility companies. Construction crews often are left guessing on the location of underground lines. Proposed strategies to resolve the issue, such as installing tracer wires alongside plastic pipe, have proven to be problematic and unreliable.
“Utilities have used this kind of milk jug plastic since the 1960s, but the pipes can degrade and start to crack,” said Associate Professor of Mechanical Engineering Michael Keller.
Keller, who has conducted research for the U.S. Department of Transportation since the early 2000s, has received a new round of DOT funding to develop an alternative pipeline material. The three-year $300,000 grant also provides resources to investigate a more efficient method to locate and track underground utility lines.
The research will involve outside collaboration with Raman Singh, professor of mechanical engineering at Oklahoma State University, as well as an OSU graduate student. Other investigators include Peter Hawrylak, TU assistant professor of electrical engineering, and two TU grad students. The team will follow two strategies for fabricating underground plastic pipe capable of responding to an electromagnetic signal. The first involves incorporating micro-encapsulated magnetic nanoparticles into the plastic.
“The microcapsules will reduce some of the harmful effects conductive particles can have on mechanical properties,” Keller said. “These magnetic microcapsules will make the plastic pipe look like a metal pipe to the utility locating tools used by gas companies. We may also be able to make this material self-heal any damage that occurs during the life of the pipe.”
Keller’s background in self-healing composites will play an important role in developing a new pipe that can heal itself when damaged. The other aspect of the research involves Hawrylak’s expertise in radio-frequency identification systems (RFID); he will experiment with RFID antennas to determine the pipe’s location and read its data. The information will provide an underground snapshot of the pipe’s integrity, eliminating the need for excavation while reducing cost and the risk of accidental damage. RFID technology will help utility services identify the pipe’s type, depth, shape and size. Hawrylak said the antennas also have the potential to gather data from neighboring pipes and provide landmarks to draft a thorough underground utility map.
“We’ll use an antenna from a RFID tag to locate the pipe and then install different antennas to encode information into the pipe,” Hawrylak said. “Specific code will help us detect what type of pipe it is and maybe even how far it runs in a certain direction.”
Its “smart pipe” capabilities will allow the RFID antennas to host multiple sets of data and act as a GPS coordinate for detecting underground lines.
Keller said the goal is to fabricate pipelines that can provide a reliable plastic pipe system that is easy to manufacture, cost-effective and quickly locatable.