薄型巻付け耐火被覆材と工法の開発
開発中の薄型の巻き付け耐火被覆の改良を実施した。これまでに試作した被覆材や施工に用いる金物を使用した加熱実験では被覆材が割れる、金物が外れるといった課題があった。被覆材の割れは加熱時の膨張により厚さが変わることで出隅部に加わる引張力と施工時に加わる引張力が原因であると考え配合の再検討と不織布を表面に設けるといった対策を行った。施工方法では載荷加熱による試験体及び金物の変形により金物が外れたと考えられることから最初から変形を許容し変形に追従することが可能な形状へと変更を行った。改良後の試験体及び材料で製作した試験体で加熱実験を行った。載荷加熱試験の結果試験体は脱落せず、鉛直変位も規定値を下回り、鋼材はりの1時間耐火構造の基準値を満たすことが確認できた。
キーワード：耐火被覆，乾式，薄型，無火気
＊１ 技術センター 先進技術開発部 次世代建設技術開発室
Development of Slim Wrapping Refractory Coating Material and Method for Its Application
We improved the slim wrapping refractory coating that is currently under development. In previous heating tests with prototype coating materials and mounting hardware, there were issues such as the cracking of the coating material and the detachment of the mounting hardware. We considered that the causes of coating material cracking were tensile forces that the corners were subject to and the tensile forces generated during application as the thickness changed due to expansion during heating. We thus took measures including a revision of the formulation and the addition of non-woven fabric to the surface. As for the application method, we changed the shape to allow for deformation from the beginning onward and to follow the deformation, considering that the mounting hardware came off due to the deformation of the test specimens and mounting hardware during a fire resistance test under load. We conducted a fire resistance test under load on test specimens made of improved materials and on specimens made with the new application method. As a result, we confirmed that the steel beam covered by the refractory coating satisfied the standard value for a 1-hour fire-resistant structure without detaching from the beam and with the vertical displacement controlled below the specified upper limit.
Keywords: refractory coating, dry, slim, no fire
*1 Next-Generation Construction Technology Development Section,Advanced Technology Development Department,Taisei Advanced Center of Technology