Moisture Absorption of Laminated Bamboo Composite and its Influence on Mechanical Properties

Laminated bamboo composite (LBC) has received a great attention due to its environmental friendly characteristics and excellent physical and mechanical properties, therefore it is necessary to investigate the durability of the LBC material in ambient environment (temperature and relative humidity). In this paper, firstly, LBC materials were manufactured in laboratory. Moisture absorption and thickness swelling kinetics of the materials at different temperatures and relative humidity were investigated. Then effects of ambient environment on mechanical properties were evaluated at three different ambient temperatures (21 °C, 36 °C, and 60 °C) and different moisture contents. It is found that the moisture absorption and the thickness swelling increase with temperature, relative humidity and ageing time before an equilibrium condition is satisfied. Parameters of the diffusion coefficient and the swelling rate increase with the temperature. In addition, there is a significant decrease in mechanical properties of the moisture-saturated specimens compared to the dry ones. And the degradation of the bending property and the compressive strength is found to be a function of the moisture absorption during the initial period and becomes stable as the absorption process approaches equilibrium. Finally, surface erosions are shown by scanning electron microscopy (SEM) after the hydrothermal aging at 60 °C.