In 1998 researchers Sherif Yihia and Christopher Tuan reported on conductive concrete. Yihia and Tuan stated that common methods of bridge de-icing, such as spreading salt, meet with limited success. A type of concrete developed is called conductive concrete, which conducts an electric current. When a voltage is applied to both sides of a block, the concrete heats up, melting the ice on top of it.
Civil engineer Bradley J Taylor wrote his master's thesis on fiber-reinforced polymer in December of 2009 at the University of Toledo. Fiber-reinforced polymer honeycomb (FRPH) is a new type of material that can withstand heavy traffic, but is more energy efficient to heat from below than concrete. This material is fiberglass based, and it is also lighter than concrete. In early 2011 this technology is in its infancy, and Taylor states that not many long-term studies have been done on FRPH to date.
Three methods of heating road surfaces on bridges have been explored by various government and private organizations. Researcher Feng Xie explored these methods in his master's thesis at Zhejiang University in 2004. A combination of materials and methods are used to heat bridge surfaces. First, pipes are embedded in the concrete as it is being poured. Either hot fluid or hot gas is circulated in the pipes, so the concrete heats up. This is called a hydronic system. Another method is called heat pipes. Sealed pipes with fluid are embedded in the concrete, and the fluid is heated up on one side. Convection currents carry the heated fluid from one side of the pipe to the other. Another method being explored is heating strips. Electrical heating elements are embedded into the concrete. Electricity is applied to the elements, and the concrete heats up. All three methods combine concrete with an embedded heat source to thaw out the road surface or to keep it from freezing in the first place.
All the materials and methods have to use energy to heat the road surface. Xie explored geothermal heat as the energy source. A heat pump is used to extract heat from the ground. The heat is used to warm up the working fluid inside the hydronic pipes. This is a more efficient method than to use electricity to heat the concrete, since the electricity used to drive the heat pumps is less than to drive electrical heating elements.