Overview on FRB Pre-Stressed Tendons and its Fatigue Behavior

Due to population growth and development of industry and transportation, the environment of human is started to become considerably polluted. Aggressive atmosphere and ground water increase the risk of corrosion of embedded reinforcement in concrete. The addition of waterproofing materials on concrete surface to minimize the amount of water and air that reaches the steel reinforcements through cracks. But waterproof materials are often expensive and need maintenance several times over the structure’s lifetime. The situation is more dangerous for pre-stressing tendons in pre-stressed bridges, deterioration of highway concrete bridges due to tendon corrosion has been large problem in many countries. Structural engineers dealing with durability of concrete greatly concern about possibilities to improve service life of embedded reinforcements.

Several proposals have been presented so far from the developments of concrete technology to the use of epoxy coated reinforcements; however, these did not always lead to the expected results. Early man was aware of the basic principle that a composite material is greater than the sum of its parts. For example, clay and straw were found to be stronger than clay alone; straw being the fibrous reinforcement and clay being the matrix. Currently, worldwide research is going on to find suitable FRP materials such as FRP reinforcing bars, pre-stressing tendons/strands, plates, and sheets for internally and externally reinforced and pre-stressed concrete structures and to derive best possible structural efficiency in terms of structural strength and life with little maintenance. All the FRP materials have added advantages over the conventional materials, due to its superior strength, stiffness, and durability qualities.