Long-term Degradation Mechanisms of Bond in Concrete Reinforced with Fiber Reinforced Polymers (FRP)

Project Abstract

Long-Term Degradation Mechanisms of Bond in Concrete Reinforced with Fiber Reinforced Polymers

Thomas E. Boothby, The Pennsylvania State University

Charles E. Bakis, The Pennsylvania State University

The repair of the nation's deteriorating infrastructure requires the development and qualification of new materials. A class of composite materials known as fiber reinforced polymers (FRP), originally developed through basic research for use in the aerospace industry, have been gaining acceptance over the last two decades as suitable materials for reinforcement and repair of concrete structures, as well as for other construction applications. These materials have the advantage of exceptional strength-weight ratios and resistance to corrosion. However, the widespread adoption of these materials to repair and reinforcement of bridges, buildings, and other structures requires an understanding of the complex processes of environmental degradation, so that the material can be designed and built to be sufficiently durable.

FRP's applied to reinforcement for concrete may be internal, such as reinforcing bars, or external, such as adhered plates or sheets. The external reinforcement may be used to repair or strengthen existing structures. In all cases, the ability of the material to bond to concrete over the lifetime of the structure (50-100 years, typically), and under continual environmental attack--due to acid rain, freeze-thaw, heat and humidity, etc.--is critical to its success as a reinforcing material. The proposed research will examine in detail the characteristics of bond between FRP reinforcing, both external and internal, and concrete, and the process of degradation of this bond due to age, long-term loading, and environmental effects. The research will investigate small and intermediate scale specimens aged in outdoor environments in temperate and tropical climates, and subjected to accelerated environmental conditioning. The research will enable designers of these materials to predict their durability with increased confidence.