Water absorption of wood polypropylene composite sheet piles and its influence on mechanical properties
Published: 2011
Publication Name: Construction and Building Materials
Publication URL: https://www.sciencedirect.com/science/article/pii/S0950061811001711
Abstract:
The water absorption behavior and durability of extruded wood polypropylene composite (WPC) material used in Z-section sheet piles was investigated. An experimental technique to determine percentage water absorption and its effect on mechanical properties was implemented. Water absorption tests were carried out on specimens cut from flanges and webs of the Z-section by immersion in tap water at 21, 45 and 70 °C. Freezethaw resistance of saturated composites was studied by cycling temperatures in the range of 21 to ?29 °C. The absorption behavior followed the kinetics of a Fickian diffusion process. This behavior was modeled using an analytical solution based on Ficks second law of diffusion. Quasi-static bending tests were conducted periodically on specimens immersed in water to assess degradation in flexural properties. A significant decrease in mechanical properties of the water-saturated specimens compared to the dry control was observed. Degradation of flexural modulus was found to be a strong function of water absorption with initial decrement as percentage water absorption increased and finally stabilized as the absorption process approached saturation. However, freezethaw cycling did not have any significant effect on mechanical properties of saturated composites. A phenomenological model for moisture intrusion and its effect on mechanical properties was implemented and applied to explain the experimental findings.