A Study on Improving Quality of Softwood Plywood for Formwork and its Construction Method

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K14875
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 23010:Building structures and materials-related
• Research Institution: Institute of Technologists (2021-2022); Nihon University (2020)
• Principal Investigator: Aramaki Takumi ものつくり大学, 技能工芸学部, 講師 (70821982)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: コンクリート型枠用合板 / 吸水防止材 / 含水率 / 曲げ剛性 / 転用 / 表層品質 / 仕上がり状態 / 変形

Outline of Final Research Achievements

The effectiveness of water repellent materials was examined to suppress the deterioration of plywood quality during formwork construction, revealing their inhibitory effects. The application of water repellent materials demonstrated the ability to suppress the increase in moisture content due to water absorption, which leads to a decrease in strength and stiffness of plywood in outdoor environments, as well as the deformation caused by cyclic wetting and drying. Additionally, while there are variations in plywood quality depending on the species of the veneer, it was confirmed that the quality changes associated with the reuse of plywood and the influence of reused plywood on the finishing condition of concrete surfaces generally exhibit similar trends. Based on these findings, a design and construction method for vertical formwork was proposed, taking into account the quality of plywood and construction conditions.

Free Research Field

建築材料・施工

Academic Significance and Societal Importance of the Research Achievements

鉄筋コンクリート工事では，型枠材料として南洋材合板が多用されてきた。環境問題への取組みとして，持続的な生産・再生が可能な針葉樹材を用いた合板への代替が期待されているが，強度・剛性の低下や乾湿の繰返しによる変形などに懸念が残ることから，限定的な使用に留まっている。本研究では，吸水防止材による合板の劣化抑制に加えて，合板の転用および型枠の構成方法などの型枠の設計・施工に関わる検討を行った。本研究の成果は，コンクリート部材の要求性能を確保する上で重要な点であり，合板の品質および施工条件を考慮した型枠の設計・施工方法の体系化の一助となることや，針葉樹合板の利用拡大に寄与することが期待される。