In this work the moisture diffusion process and the influence of moisture on mechanical properties (critical strain energy release rate in mode I (GIC), flexural modulus and ultimate flexural strength) of GRP pipes was assessed. The research was performed on specimens conditioned in two different environments, water at room temperature and water at 50°C. In this case it was verified that the water diffusion can be well described by the Fick’s second law.
The critical strain energy release rate in mode I, GIC, shows a decrease between 5% and 10% when conditioned in water. The temperature of the conditioning does not have so much influence on the GIC values.
The conditioning either in water at room temperature or at 50°C has an influence on the flexural modulus and strength of the pipes in the hoop direction, between 10% and 20%, respectively. The longitudinal modulus was more significantly affected by the conditioning in water at 50°C with a 30% decrease.
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