• Introduction and Background:
Reinforced concrete deterioration induced by corrosion of steel reinforcement is considered one of the well-known and costly problems associated with concrete bridges (Sohanghpurwala 2006). The deterioration problems are steadily increasing as one or a combination of many factors such as poor design, inappropriate used materials, and severe environmental changes accelerate the deterioration process in concrete structures (Broomfield 2007). The durability problems of concrete bridges and its consequences are countless in terms of annual maintenance cost and service life. The Department of Transport’s (DoT) in the United Kingdom estimated expenses of 616.5 million pounds of salt-induced corrosion damage in road bridges as well as motorway in England and Wales only (Wallbank 1989). According to Broomfield (2007), the eventual cost might reach 10 times of the DoT estimate as those bridges represent 10% of the total bridges number in the UK. In addition, the U.S. Federal Highway Administration (FHWA) has reported that one third of the total bridges in the U.S. have severe structural defects and one fourth of them have passed the average design service life of a bridge. Therefore, it is crucial to investigate cost-effective ways to prevent or lessen the corrosion consequences in concrete bridges.
Extensive studies have been carried out to investigate the service life for bridge girders and decks using corrosion resistant material technologies such as Fiber Reinforced Polymer (FRP) and epoxy coated tendons (Abendroth et al. 1994, Fam et al. 1995, Zylstra et al. 2000). These materials have high resistance to the corrosion, high strength characteristics, and normal construction procedure. However, they are much expensive than commonly used materials such as prestressing and non-prestressing steel reinforcements. Also, they require special quality control in the storage, handling, and placement. Since FRP composite materials or epoxy-coated reinforcement have a higher material cost than conventional steel reinforcement, hybrid systems containing both materials can be developed to combine the benefits of each in a cost-effective way. This system could be called Hybrid Concrete Structural Elements (HCSE). In this system, the new materials are strong enough to achieve the required capacity as well as to deplete the environmental problems related directly to the corrosion of reinforcing steel, while the conventional materials can sustain the structural behavior to an acceptable level.
A research program sponsored by Missouri Department of Transportation (MoDOT) (Sneed et al. 2010, Issa 2010) provided a potential effort of using CFRP and epoxy coated tendons along with prestressing steel tendons in precast prestressed panels aiming to solve the concrete spalling generated by corrosion of steel. The research recommended to replace four edge steel tendons by CFRP tendons or epoxy coated tendons as the spalling problem was...