Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
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A Study on the Block Shear Strength according to the Layer Composition of and Adhesive Type of Ply-Lam CLT

Ply-Lam CLT의 층재 구성 및 접착제 종류에 따른 블록전단강도에 관한 연구

  • CHOI, Gyu Woong (Department of Bio-based materials, Chungnam National University) ;
  • YANG, Seung Min (Department of Bio-based materials, Chungnam National University) ;
  • LEE, Hyun Jae (Department of Bio-based materials, Chungnam National University) ;
  • KIM, Jun Ho (Department of Bio-based materials, Chungnam National University) ;
  • CHOI, Kwang Hyeon (Huin co., Ltd.) ;
  • KANG, Seog Goo (Department of Bio-based materials, Chungnam National University)
  • Received : 2020.08.02
  • Accepted : 2020.10.13
  • Published : 2020.11.25
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Abstract

In this study, a block shear strength test was conducted to compare and analyze the strength and failure mode on the glued laminated timber, CLT, and Ply-lam CLT, which are mainly used for the construction of wood construction as engineering wood. Through this, the Ply-lam CLT manufacturing conditions for optimum production, such as the type of lamina, plywood, adhesive, and layer composition, were investigated. The results are as follow. Through block shear strength test, it showed high strength in the order of glued laminated timber, Ply-lam CLT and CLT. In particular, the shear strength of Ply-lam CLT, which is made of a composite structure of larch plywood and larch lamina, passed 7.1 N/㎟, which is a Korean industrial standards for block shear strength of structural glued laminated timber. In addition, in this study, there was no different in shear strength according to the adhesive type used for glulam, CLT, and Ply-lam CLT adhesion. However, in the case of Ply-lam CLT, the difference in shear strength of Ply-lam CLT was shown according to the type of lamina and plywood. The results showed high strength in the order of Larix kaempferi > Mixed light hardwood ≒ Pinus densiflora, sieb, et, Zucc plywood. The optimal configuration of Ply-lam CLT is when larch plywood and larch lamina are used, and it is decided that the adhesive can be used by selecting PRF and PUR according to the application. The results of block shear strength failure mode by type of wood based materials were analyzed. The failure mode showed shear parallel-to-grain for glulam, rolling shear for CLT, and shear parallel-to-grain and rolling for ply-lam CLT. This is closely related to shear strength results and is decided to indicate higher shear strength in Ply-lam CLT than in CLT due to rolling shear.

본 연구에서는 공학목재로 목구조건축에 주로 사용되는 집성재 및 CLT 그리고 Ply-lam CLT의 블록전단시험을 실시하여 강도 및 파괴 유형을 비교 분석하였다. 이를 통해 Ply-lam CLT의 라미나 및 합판의 수종, 접착제의 종류 및 Layer구성 등 최적생산을 위한 제조조건을 구명하고자 하였으며 그 결과는 다음과 같다. 블록전단시험을 통해 집성재, Ply-lam CLT, CLT 순으로 높은 강도를 나타냈다. 특히, 낙엽송 합판과 낙엽송 라미나의 복합구조로 제조되는 Ply-lam CLT의 전단강도는 집성재 전단강도 기준인 7.1 N/㎟을 통과하였다. 아울러 본 연구에서는 집성재, CLT, Ply-lam 접착에 사용된 접착제 종류에 따른 전단강도의 차이는 나타나지 않았다. 그러나 Ply-lam CLT의 경우에는 라미나와 합판의 수종에 따라 Ply-lam CLT의 전단강도의 차이를 나타냈다. 그 결과는 낙엽송 > 남양재 ≒ 육송 합판 순으로 높은 강도를 나타났다. Ply-lam CLT의 최적 구성은 낙엽송 합판과 낙엽송 라미나를 사용하는 경우이며 접착제는 용도에 따라 PRF, PUR을 선정하여 사용하면 될 것으로 판단된다. 목질재료 유형에 따른 전단강도 파괴 양상 결과 분석을 통하여 집성재는 shear parallel-to-grain, CLT는 rolling shear, Ply-lam CLT는 shear parallel-to-grain과 rolling shear가 복합적으로 나타났다. 이는 전단강도 결과와 밀접한 관련이 있으며 rolling shear로 인하여 CLT보다 Ply-lam CLT에서 더 높은 전단 강도를 나타내는 것으로 판단된다.

Keywords

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