Durability study of pultruded carbon fiber reinforced polymer plates subjected to water immersion

Abstract

Pultruded carbon fiber reinforced polymer plates have been widely used for structural rehabilitation due to their excellent mechanical properties. Even though, the long-term durability performance of carbon fiber reinforced polymer plates is still a concern, especially when subjected to harsh environmental conditions (e.g. water immersion). In the present study, the effects of water immersion at 23°C, 40°C, and 60°C on the degradation of the pultruded carbon fiber reinforced polymer plates were investigated in terms of water uptake and mechanical properties. To elucidate the degradation mechanisms, the resin matrix and the fiber and resin adhesion were also assessed in the same conditions. The test results indicated that water immersion, especially at higher temperatures, leads to serious fiber debonding, and thus the carbon fiber reinforced polymer samples absorb much more water than the resin matrix. In addition, the transverse flexural strength of the carbon fiber reinforced polymer plates, closely correlated to the fiber–resin adhesion, reduced significantly at high temperatures. On the contrary, the resin matrix and carbon fiber reinforced polymer plates show much less degradation subjected to the same immersion conditions. Therefore, to comprehensively understand the long-term durability of a carbon fiber reinforced polymer material, it is necessary to test the variation of the bonding strength between fiber and resin matrix, in addition to the tensile performances in fiber directions of the carbon fiber reinforced polymer plates.