ABSTRACT

This paper gives a brief overview of the durability issues of polymer composites with some specific references to cold regions applications. The mechanisms that control the durability include: (1) chemical or physical changes of the polymer matrix, (2) loss of adhesion or debonding at the fiber/matrix interface or delamination between an FRP composite overlay and the structural element it is bonded to, and (3) reduction of fiber strength and modulus. The environment plays a crucial role in changing the properties of polymer matrix composites. Both the ambient environment and the loading environment have been considered, which may act together. In the ambient environment, both matrix and fibers may be affected by moisture, temperature, sunlight (UV radiation), ozone, and the presence of degrading chemicals such as salts or alkalis. Repeated exposure to very high and low temperatures (freeze-thaw cycling), too, may introduce some changes. Under a mechanical loading environment repeated loading might introduce fatigue in composites. Sustained load over a period of time may cause the material to creep. Some examples of studies on aging and fatigue cycling have been given.