Durability of FRP immersed in water. Changes in mechanical properties

Abstract

Fibre Reinforced Polymers (FRP) have been widely used to strengthened construction structural elements in the last years because of their mechanical pros. However, the durability of these materials is always controversial. In particular, the effect of long-term contact with water on the mechanical properties of FRPs is studied in this research throughout the implementation of accelerated degradation tests. Samples of Carbon FRP and Glass FRP were immersed into supply water, water with salts and surfactants and highly chlorinated water. In all cases, electrical current passing through the samples was also imposed. Tensile tests on pristine and degraded samples were carried out to determine the influence of these aggressive environments on the tensile strength and the Young’s modulus of the specimens. Finally, superficial (ATR) FT-IR analyses were conducted to assess possible chemical changes in the samples surfaces. Results indicated that the chemical composition of used resins was not modified due to the water exposure. No hydrolysis process took place during testing time on the surface. However, mechanical properties were reduced, especially when samples were exposed to plain supply water, which may be related to the physical degradation caused by moisture intake by diffusion.