耐熱性改質エポキシ樹脂を用いた集成棒材接合部の耐火性に関する実験的検討

Experimental Investigation on the Fire Resistance of Glued-In Rod Timber Joints with Heat Resistant Modified Epoxy Resin.

• Liquan Luo
• Benkai Shi
• Weiqing Liu
• Huifeng Yang
• Zhibin Ling

抄録

本稿では，エポキシ樹脂を用いた集成棒材接合部の耐火性について，耐熱性改質エポキシ樹脂を用いた場合と用いない場合の実験的評価を行った。エポキシ樹脂に無機添加剤を添加して耐熱性を向上させた耐熱性改質樹脂を設計した。この改良エポキシ樹脂を用いて常温で製作した接合部は，市販のエポキシ樹脂と同等の耐力を有していた．改良エポキシ樹脂を用いた21本と市販エポキシ樹脂を用いた6本の継手試験片について、耐火性を評価するために耐火炉内で試験を行った。その結果，主な破損モードは，この種の継手の火災試験に典型的に見られるロッドの引き抜きであった．試験パラメータの影響については，接着剤の種類，断面サイズ，応力レベル，耐火被覆の影響を考慮した．その結果，市販のエポキシ樹脂を用いた場合と比較して，樹脂を変更した場合は73％，耐火被覆を用いた場合は35％の改善が見られ，継手の耐火期間が明らかに改善されることが分かりました．また，いずれの試験片においても，応力度の増加とともに耐火期間が減少し，断面積の増加とともに耐火期間が増加することが明らかになった．

This paper presents an experimental evaluation of the fire resistance of glued-in rod timber joints using epoxy resin, with and without modification. A heat-resistant modified resin was designed by adding inorganic additives into the epoxy resin, aiming to improve the heat resistance. Joints that were made using the modified epoxy resin at room temperature showed a bearing capacity comparable to those with commercial epoxy resin. Twenty-one joint specimens with the modified epoxy resin and six with a commercial epoxy resin were tested in a fire furnace to evaluate the fire resistance. The main failure mode was the pull-out of the rod, which is typical in fire tests of this type of joints. As to the effects of the test parameters, this study considered the effects of adhesive types, sectional sizes, stress levels, and fireproof coatings. The test results showed that the fire resistance period of a joint can be evidently improved by modifying the resin and using the fireproof coating, as the improvements reached 73% and 35%, respectively, compared with the joint specimens with commercial epoxy resin. It was also found that, for all specimens, the fire resistance period decreased with an increase in the stress level and increased with an increase in the sectional sizes.