Penetration of Water into Hardwoods
Keywords:<i>Liriodendron tulipifera</i>, <i>Quercus shumardii</i>, <i>Juglans nigra</i>, swelling, bound moisture, free moisture, diffusion, temperature
The longitudinal penetration of water into hardwoods was studied by continuously measuring swelling and uptake in a swelling cell apparatus. Mathematical equations were developed to relate swelling, bound moisture uptake, free moisture uptake, and time of penetration. The initial stages of bound moisture uptake and free moisture uptake were each shown to be linear when plotted against the square root of time.
Bound and free moisture penetration constants were calculated from swelling and uptake data for different wood species at different temperatures. The transport of bound water by vapor and water diffusion became more important than transport by capillarity as temperature increased, or when wood species with obstructed vessels were used. The relative amount of water uptake distributed between bound moisture and free moisture was shown to change with increasing temperature.
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