Water Absorption Behavior and Its Influence on Properties of GRP Pipe

Abstract

With the rapid development of glass-fiber reinforced plastic (GRP) pipes in civil infrastructure under different environments, it is essential to understand the fundamental mechanisms responsible for the pipe failure. However, research reports on water absorption behavior and its influence on the performance of GRP pipe are few in the literatures. This study provides test results of water diffusion in a GRP pipe wall and its influence on the properties of the pipe. When the environment is water, it attacks each component of the GRP pipe. In this study, the water absorption behavior of three different types of GRP pipe is recorded. One of them (UP-A pipe) presents near-Fickian behavior, the other two types of pipe behave like a two-stage diffusion. A model developed from Fick's law is used to predict the water diffusion process for the three pipes. The prediction agrees well with the experimental data for the UP-A specimen, while the same cannot be transferred to EP-A and UP-B specimens because of the abnormal non-Fickian process. The influence of moisture on flexural properties, interlaminar shear strength, and viscoelastic properties of a GRP pipe is also discussed.