Evaluation of Electrically Conductive Concrete Containing Carbon Products for Deicing

Abstract

Using electrically conductive concrete for deicing is an emerging material technology. Due to its electrical resistance, a thin layer of conductive concrete can generate enough heat to prevent ice formation on concrete pavement when energized by a power source. Under research sponsored by the Nebraska Department of Roads, a concrete mixture containing steel fibers and shavings was developed specifically for concrete bridge deck deicing. The mixture has a compressive strength of 31 MPa and provides average thermal power density of 590 W/m-sq. with a heating rate of 0.14 deg C/min in a winter environment. During development of the conductive concrete, several drawbacks about using steel shavings in the mixture were noticed. As a follow-up effort, carbon and graphite products were used to replace steel shavings in the conductive concrete design. The electrical conductivity and the associated heating rate were improved with the carbon products. A conductive concrete deck has been implemented for deicing on a highway bridge at Roca, located approximately 15 miles south of Lincoln, Nebraska. The Roca Spur Bridge has a 117-ft-long and 28-ft-wide conductive concrete inlay, which has been instrumented with temperature and current sensors for heating performance monitoring during winter storms. Experimental data and operating costs are presented herein.