Abstract

Three species of Italian poplar (Populus euramericana), red pine (Pinus densiflora) and oriental oak (Quercus variabilis) were selected for this study. They were cut so that the distances between each of tips and roots for a pair of fingers were 0, 0.15, 0.30 and 0.45 mm. Poly vinyl acetate (PVAc) and resorcinol-phenol resin (RPR) were used for finger-jointing. Compressive test parallel to the grain was conducted for the finger-jointed specimens. The results were as follows: The efficiency of compressive Young's modulus of finger-jointed timber to solid wood indicated low values, whereas the efficiency of compressive strength indicated high values of more than 90% in all species, especially, it was found that those of red pine indicated markedly high values of more than 97%. The efficiency of compressive displacement of Italian poplar finger-jointed timber was 2 times higher than solid wood, and it was 1.2 and 1.3 times higher than solid woods in red pine and oriental oak, respectively. Also, it was found that 0, the distance between each tip and root for the fingers, indicated the highest efficiency of compressive strength performance in Italian poplar finger-jointed timber, and for red pine and oriental oak finger-jointed timbers, the distances of 0.15 and 0.30 were found to indicate the highest efficiency.

본 연구에서는 국내산 이태리 포플러, 소나무 및 굴참나무를 공시재료로 초산비닐(PVAc), 레조시놀-페놀 공축합 수지(RPR)접착제를 사용하여 핑거공차별(0, 0.15, 0.30, 0.45 mm)로 핑거 접합재를 제작하였고, 종압축 강도성능 시험을 실시하여 다음의 결과를 얻었다.종압축 영률 유효율은 3수종 모두 소재에 비해 현저히 감소하였고, 종압축 강도 유효율은 3수종 모두 평균 90%이상의 높은 유효율을 나타내었다. 특히 소나무재의 경우 모든 조건에서 97% 이상의 높은 유효율을 나타내었다. 최대 변위 유효율은 이태리 포플러재의 경우 소재의 2배, 소나무재와 굴참나무재의 경우 각각 소재의 1.2와 1.3배 정도로 높게 나타났다. 핑거공차에 따른 영향에서는 이태리 포플러재의 경우 핑거공차 0에서 가장 높은 압축강도 유효율을 나타내었고, 소나무재와 굴참나무재의 경우 핑거공차 0.15와 0.30에서 가장 높은 강도 유효율을 나타내는 것이 확인되었다.

Keywords

• compressive Young's modulus;
• compressive strength;
• displacement finger-jointed timber