Article

New concrete makes snow disappear

“It should make a snow-melting system more practical than existing ones.” Clayton Hallmark, vice president of technology, Grouding Systems, LLC
Amy Nichols - Daily Nebraskan (U. Nebraska)

(U-WIRE) LINCOLN, Neb. – People always have complained about the back-breaking labor of shoveling sidewalks each winter.

But now help may be on the way.

University of Nebraska researchers Christopher Tuan and Sherif Yehia have developed a type of pavement – known as conductive concrete – that works by making the pavement a conductor of electricity to warm the sidewalks, melting ice and snow on contact.

Graphite and carbon in the concrete turn otherwise ordinary sidewalks into conductors of electricity. Once the conductive concrete is connected to a power source, the heat generated melts the ice.

This winter the method will be put to the test in Shelby, Ohio, where it has been installed on sidewalks in front of two city buildings.

Clayton Hallmark, who is working with conductive concrete as the vice president of technology at Grounding Systems LLC in Shelby, found Tuan and Yehia’s Web site and convinced the town to try the method.

“The conductive concrete is maintenance-free. It should make a snow-melting system more practical than existing ones,” Hallmark said.

Yehia said electrodes are installed to create the electricity. Temperature sensors also are installed to monitor the pavement and keep it at a safe temperature. The electrodes are connected to a power source only when a snow storm is coming, so it only produces heat when there is snow and ice to melt. To ensure public safety while the pavement is being heated, a thin polymer coating will be added to the surface as an insulator, Yehia said.

Tuan said the concrete only needed to be installed once, unlike road salts and chemicals that have to be applied numerous times and cause damage to roads, he said. The cost of installation is higher for the conductive concrete than for traditional sidewalks, but the money saved from not having to replace concrete deteriorated by salt would pay for the higher installation costs.

“Using salt on concrete induces an alkali-silica reaction in the concrete. The reaction produces a gel that, in the presence of moisture, expands and may cause cracking of mortar and concrete,” Tuan said. “Surface cracks are aggravated by the freeze-thaw action, leading to corrosion, potholes and structural failure.”

Yehia agreed not having to use salt would solve problems.

“In addition it will add years to the lives of bridges and reduce maintenance costs,” he said.

The idea for the concrete came to Tuan in 1995 when he was working for the U.S. Air Force Pavements Division, at Tyndall Air Force Base in Florida. He thought of mixing steel fibers and steel shavings into the concrete to make the concrete electrically conductive in order to remove ice from the runways.

Because of military budget cuts, Tuan never had a chance to test his idea with the Air Force. Yehia joined Tuan in researching in 1997.

Now the main objective of the research is to find a de-icing method that is safe for structures and humans.

“Ice on paved roads is not merely a concern for motorists. Ice on pedestrian walkways accounts for numerous personal injuries due to slipping and falling,” Tuan said. “The payoff potential is tremendous. It would eliminate icy bridge roads for wintry travel safety and save lives.”