The Study On Accelerated Aging Method And Aging Resistant Performance Of Parallel Bamboo Strand Lumber

This paper mainly discussed and studied aging resistant performance of parallel bamboo strand lumber from three aspects:First,according to three kinds of manual accelerating aging methods,including ASTM D1037,BS EN1087-1 and European AFNOR V313,following conclusions were obtained:After aging processing,thickness swelling of the samples was between3%and 11.5%,thickness swelling of 24 hours' water absorption was between 1%and 3.5%,MOE and MOR both decreased by 12%to 33%,and MOE were all above 8000MPa,MOR were all above 80MPa, which testify the good mechanical property of parallel bamboo strand lumber.The decline of internal bond strength was the most significant which was between 45%and 66%.BS EN1087-1 accelerating aging processing takes only 4.5 to 5.5 hours as ASTM D1037 takes at least a week,so the previous one is much better in application for its time saving.Second,the paper discussed the aging resistant performance of three kinds of parallel bamboo strand lumber.According to experimenting,following conclusions were obtained:In all three kinds of panels,cold pressing panels' aging resistant performance is not so good.Hot pressing panels' mechanical properties declined fewer,but its dimensional stability is worse than heat treated-hot pressing panels'.After accelerating aging processing,water absorption and swelling of cold pressing panels changed largest,which is followed by hot pressing panels',and then heat treated-hot pressing panels'.For all three kinds of panels,thickness swelling changed larger than width swelling.Modulus of elasticity(MOE) and modulus of rupture(MOR) of cold pressing panels changed fastest and largest which is followed by heat treated-hot pressing panels',and then hot pressing panels'.Internal bond strength(IB) change of three kinds of panels seems with tiny difference.In detail,IB of hot pressing panels is the largest and IB of cold pressing panels is the smallest.Third,laboratory test of natural decay resistance of bamboo sticks and parallel bamboo strand lumber was done and following conclusions were obtained:After moldering by wood-decaying fungus,weight of samples declines.All the rate of lost mass is between 1%and 12%.The weights loss of bamboo sticks without any treating and 150~Cheat-treated bamboo sticks are above 11%,but less than 24%after moldering,so they're remain with levelⅡ(decaying-resistant).Other kind of samples remain with levelⅠ(great decaying-resistant) as the weight losses are all less than 11%.In all samples,bamboo sticks without any treating are moldered worst.200℃heat-treated bamboo sticks after moldering are better than 150℃heat-treated bamboo sticks.The weight loss of cold pressing panels is the largest which is followed by hot pressing panels,and then heat treated-hot pressing panels.Coriolus versioolor moldered all the panels more significant than Poria plaoenta did.