Flexural creep of structural flakeboards under cyclic humidity

Abstract

Flexural creep behavior of randomly oriented structural flakeboards under cyclic humidity is presented. Specimens fabricated with 5 and 7 percent phenol-formaldehyde resin were subjected to constant concentrated load in bending under slow and fast cyclic relative humidity (RH) between 65 and 95 percent for 100 days. The temperature was set at a constant 75°F through the test duration and each humidity level was maintained for 33 days (slow cycle) and 2 days (fast cycle). Boards made with sweetgum flakes showed better creep resistance than those made of white oak. Significant effect on the creep resistance was observed when the resin content was increased from 5 to 7 percent under highly humid environments. Large deflections occurred and large permanent deformations remained for both groups after the relaxation.

Citation

Yeh, M.C.; Tang, R.C.; Hse, Chung-Yun. 1990. Flexural creep of structural flakeboards under cyclic humidity. Forest Products Journal 40(10):51-57