Conductive Concrete Overlay for Bridge Deck Deicing
Sherif Yehia and Christopher Y. Tuan
Appears on pages(s):
bridge decks; deicers; fibers; heat transfer; reinforcing steels
Concrete bridge decks are prone to ice accumulation. The use of road salts and chemicals for deicing is an effective method for ice removal, but causes damage to concrete and corrosion of reinforcing steel in concrete bridge decks. This problem is a major concern to transportation officials and public works due to rapid degradation of existing concrete pavements and bridge decks. The use of insulation materials for ice control and electric or thermal heating for deicing have been attempted and met limited success. Conductive concrete may be defined as a cementitious composite that contains a certain amount of electronically conductive components to attain stable and relatively high electrical conductivity. When connected to a power source, heat is generated due to the electrical resistance in the cement admixture with metallic particles and steel fibers. Based on the results of a transient heat transfer analysis, a thin conductive concrete overlay on a bridge deck has the potential to become a cost-effective deicing method. Small-scale slab heating experiments have shown that an average power of approximately 520 W/m2 (48 W/ft2) was generated by the conductive concrete to raise the slab temperature from -1.1 to 15.6 C (30 to 60 F) in 30 min. This power level is consistent with the successful deicing applications using electrical heating cited in the literature. Two large slabs are under construction for a bridge deck deicing experiment in a natural environment to monitor power consumption and deicing performance. The construction costs and experimental data will be used to evaluate the cost effectiveness of using a conductive concrete overlay for bridge deck deicing or anti-icing.