JP4257020B2

JP4257020B2 - Thermoplastic resin-coated CFRP reinforcing bar connection method

Info

Publication number: JP4257020B2
Application number: JP2000176329A
Authority: JP
Inventors: 繁宏松野; 尚之近藤; 洋治井田; 嘉司松本; 忠彦伊藤; 貴快椎名
Original assignee: Nishimatsu Construction Co Ltd; Ube-Nitto Kasei Co Ltd
Current assignee: Nishimatsu Construction Co Ltd; Ube-Nitto Kasei Co Ltd
Priority date: 2000-06-13
Filing date: 2000-06-13
Publication date: 2009-04-22
Anticipated expiration: 2020-06-13
Also published as: JP2001355313A

Description

【０００１】
【発明の属する技術分野】
本発明は、セメントモルタルやコンクリート等の無機構造材料等の補強に使用される熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法に関する。
【０００２】
【従来の技術】
セメントモルタルやコンクリート等の無機構造材の補強には鉄筋、金網などが一般的に使用されているが、これら鉄製材料は重量が大きく運搬作業性に難があった。また、鉄製材料に共通する錆びやすく低い耐食性しか有しないといった問題も存在する。このため、コンクリートにおけるかぶりが薄い場合や、海岸などの腐食性環境下でのこれら鉄製補強材の使用には大きな問題を抱えていたのが現状である。
【０００３】
他方、近年では上記の鉄製補強材に代わり、軽く扱いやすい上、錆びることのないアラミド繊維や炭素繊維などの長繊維を補強繊維としたＦＲＰ（繊維強化プラスチック）が補強材として注目され、一部実用化もされている。特に、プレキャストコンクリート用の緊張材（ＰＣ緊張材）や、ＮＯＭＳＴ（Novel Material Shield-cuttable Tunnel-wall System）工法におけるＮＯＭＳＴ補強筋、ならびにトンネル工事用のロックボルトや法面や地盤の補強用アースアンカーなどに用いられつつある。
【０００４】
上記ＮＯＭＳＴ補強筋としては、特に高強度、高弾性率で、シールドマシーンカッター刃による切削性のよいＣＦＲＰ（Carbon Fiber Reinforced Plastic）が使用されているが、なかでも炭素繊維等の長繊維を硬化性の高い、スチレン含有ウレタンアクリレート樹脂で結着した矩形状のＣＦＲＰをポリサルホン樹脂（ＰＳＦ）などの耐熱、耐アルカリ性熱可塑性樹脂により被覆一体化した構造の熱可塑性樹脂被覆ＣＦＲＰ補強筋が優れた性質を発現するとされている（特願平１１−１６５６２３号参照）。
【０００５】
【発明が解決しようとする課題】
しかしながら、このような熱可塑性樹脂被覆ＣＦＲＰ補強筋を種々の工法に適用する場合、例えばケーソン施工の場合など、当該補強筋同士を接続しなければならない状況が発生する場合がある。従来の鉄筋等の場合には互いを溶接すれば比較的容易に接続可能であるが、熱可塑性樹脂被覆ＣＦＲＰ補強筋同士の接続方法については十分な検討がなされていなかった。
【０００６】
一方、この接続作業に際しては、前述のように高強度、高弾性率、耐腐食性、及びシールドマシンによる切削良好性を要求するＮＯＭＳＴ工法等の性格から鉄製部材など在来の金属部材の使用は好ましくない。したがって、高強度、高弾性率、耐腐食性、及びシールドマシンによる切削良好性といった補強筋自体が備える特性と同程度または類似の特性を備える材料による接続により、熱可塑性樹脂被覆ＣＦＲＰ補強筋の上記性状を余すとこなく発現できる接続方法の開発が望まれていた。
【０００７】
そこで、本発明はこのような従来の課題に着目してなされたもので、接続作業が簡便であり、かつ接続後の引張り強度にも優れて、熱可塑性樹脂被覆ＣＦＲＰ補強筋の持つ優れた性状を余すところ無く発現できる熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法を提供するものである。
【０００８】
【課題を解決するための手段】
この発明は上記目的を達成するためになされたもので、略一方向に配列された補強繊維としての長繊維の束を熱硬化性樹脂で結着してなる芯部に、熱可塑性樹脂を被覆することで形成される炭素繊維強化プラスチック複合材を、コンクリート構造物等の補強筋として適用した熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法であって、接続する前記ＣＦＲＰ補強筋同士において、その端面を突き合わせる端部当接過程と、該端部当接過程において当接されたＣＦＲＰ補強筋同士の少なくとも当接箇所上下を所定サイズの補強用ＣＦＲＰ補強筋でカバーし、前記当接箇所と併せて接着剤で一体に接着する接着過程と、前記接着過程により互いに接着された前記ＣＦＲＰ補強筋を、該ＣＦＲＰ補強筋両側部に沿って一定間隔にてボルト穴を備え繊維強化樹脂製或いは繊維強化熱可塑性樹脂製の補強片により挟み込み、繊維強化樹脂製或いは繊維強化熱可塑性樹脂製のボルトにて、補強筋を貫通せず、補強筋の側部より一体に締結固定する接続補強過程とを備えることを特徴とする。
【０００９】
また、第２の発明として、略一方向に配列された補強繊維としての長繊維の束を熱硬化性樹脂で結着してなる芯部に、熱可塑性樹脂を被覆することで形成される炭素繊維強化プラスチック複合材を、コンクリート構造物等の補強筋として適用した熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法であって、接続する前記ＣＦＲＰ補強筋同士において、その端部を適宜ラップ長をもって重ね継ぎする端部当接過程と、前記端部当接過程における当接箇所を接着剤で一体に接着する接着過程と、前記接着過程により互いに接着された前記ＣＦＲＰ補強筋を、該ＣＦＲＰ補強筋両側部に沿って一定間隔にてボルト穴を備える繊維強化樹脂製或いは繊維強化熱可塑性樹脂製の補強片により挟み込み、繊維強化樹脂製或いは繊維強化熱可塑性樹脂製のボルトにて、補強筋を貫通せず、補強筋の側部より一体に締結固定する接続補強過程とを備えることを特徴とする。
【００１０】
なお、前記繊維強化樹脂製或いは繊維強化熱可塑性樹脂製の補強片は、例えばヤング率（弾性率）が９．８Ｇｐａ（1000kg/mm^２）以上のものであると好適であり、この値より小さいとボルト締めした際の圧力がボルト穴周辺に偏ってしまい締付け効果が小さくなる。また、部材の厚みは２０ｍｍ以下が作業性の点から好ましい。また、前記補強片の材質はＣＦＲＰ等だけでなく、ＧＦＲＰ（Glass Fiber Reinforced Plastic）等がコスト、剛性、強度の点から適宜選択可能である。
【００１１】
【発明の実施の形態】
＝＝＝実施例１＝＝＝
以下、本発明の好ましい実施の形態につき、添付図面を参照して詳細に説明する。
【００１２】
（１）熱可塑性樹脂被覆ＣＦＲＰ補強筋の製造
長繊維の束を被覆する被覆樹脂としてポリサルホン（商品名：ポリサルホンＰ１７００ＢＫ９３７、テイジンアモコ株式会社製）を使用し、厚さ５．５ｍｍ、幅２０．３ｍｍ（ＦＲＰ部の寸法は厚さ４．０ｍｍ、幅１９．０ｍｍ）のＣＦＲＰ補強筋（以下ＦＴＣと称する）を以下のように製造した。なおこの製造過程について特に図示はしない。
【００１３】
まず炭素繊維（商品名：トレカＴ−７００ＳＣ２４Ｋ、東レ株式会社製）５０本をスタンドより供給し、樹脂材料（商品名：ユピカ８９２１、日本ユピカ株式会社製）と、１０時間半減期の温度が７２℃である触媒（商品名：カドックスＢ−ＣＨ５０、化薬アクゾ株式会社製）を４部と、１０時間半減期の温度が１０５℃である触媒（商品名：カヤブチルＢ、化薬アクゾ株式会社製）を０．５部とを添加混合してウレタンアクリレート樹脂を形成し、これを含浸槽にて前記炭素繊維に含浸させる。
【００１４】
続いて絞りノズルで過剰な樹脂を徐々に絞り込んで断面を矩形状（縦横４×１９ｍｍ、繊維含有率５８．５ｖｏｌ％）とし、これをクロスヘッドダイスに導き、前記ポリサルホンを円環状に押出して被覆した。被覆ポイント直後より室温水により冷却した後、全長８．５ｍの熱湯硬化槽（９５〜９９℃）及び熱風発生機を利用した乾熱硬化炉（全長８ｍ、１００〜１２０℃）で硬化させる。
【００１５】
上記工程における引き取り速度は２．５ｍ／ｍｉｎとし、硬化後には被覆表面にエンボス加工を施すこととした。このエンボス加工は、予備加熱として乾熱硬化炉を使用し（１５０〜１６０℃）、ローラー温度３３０℃にて加工が行われる。そして、この熱可塑性樹脂被覆ＣＦＲＰ補強筋（以下、単に補強筋とする）を１５００ｍｍにカットし、その端末部をエポキシ樹脂が含浸されたガラステープを巻き付けることで補強し室温で２４時間硬化させた。硬化後、この補強筋について、負荷１００トンのアムスラー型引張試験機（図示しない）にて引張り試験を行ったところ、引張り強力は１９．０ｔｆ（１８６ｋＮ）となった。以下、引張り試験にはこのアムスラー型引張試験機を使用することとする。
【００１６】
（２）接合品の作成と接合部の引張強力
次に以下のように、本発明の接続方法をもって接続された補強筋の引張強力を試験するべく、試験片Ａの作成を行った。
【００１７】
長さ７５０ｍｍにカットした補強筋１０をその端面１１で突き合わせ（端部当接過程）、この端部当接過程において当接された補強筋１０同士の少なくとも当接箇所１２上下を補強用補強筋１３（長さ５００〜９５０ｍｍ）にて挟み込んだ。この挟み込み作業に続き、前記当接箇所１２と併せてこの補強用補強筋１３をエポキシ樹脂接着剤（商品名：アラルダイトＡＷ１０６、チバガイギー社製）で一体に接着し（接着過程）、更に、補強片１４として採用した補強用補強筋１３と同じ長さのＧＦＲＰ板（厚さ１０ｍｍ、幅６０ｍｍで、４０ｍｍ幅、５０ｍｍピッチで１対のφ１１ｍｍボルト穴１４ａを設けたもの。図１参照）で補強筋１０及び補強用補強筋１３を挟み込む作業を行う。このＧＦＲＰ板のヤング率は１４００ｋｇ／ｍｍ^２（１３７Ｇｐａ）であった。
【００１８】
そして繊維強化樹脂製（或いは繊維強化熱可塑性樹脂製）のボルト１５、ナット１６（例えばサイズＭ１０）にて、上記補強片１４を通して補強筋１０及び補強用補強筋１３を一体に締結固定した（接続補強過程）。この際のボルト締結トルクは、好ましくは１５Ｎｍ〜２０Ｎｍであり、また、ボルト穴１４ａの配置間隔は２０〜１００ｍｍ程度が好適である。
【００１９】
上記のように作成した試験片Ａの構造概要を図２（ａ）、（ｂ）に示す。なお、引張り試験に際して、試験片Ａの端末をエポキシ樹脂が含浸されたガラステープにより補強し評価を行った。補強用補強筋１３と補強筋１０との重ね長を５００ｍｍ〜９５０ｍｍと変化させ各重ね長における引張り試験結果を得た（実施例１−１〜１−４）。他方、比較例として重ね長を５００ｍｍと６５０ｍｍの２種設定し、その他にボルトピッチ、ボルト締付けトルクを変化させて試験を同様に行った（比較例１−１〜１−６）。これらの試験結果は表１に示す。
【００２０】
【表１】

【００２１】
比較例１−１は重ね長が他の実施例及び比較例より短く、比較例１−２、１−３はボルトの締付け間隔が他より広いため破断強力が低い結果となった。比較例１−４では接着剤の不使用、また、比較例１−５ではボルト締め無し、比較例１−６ではボルトの締付け力不足にそれぞれ由来して破断強力が著しく低くなった（比較例と実施例の試験結果ではおよそ１．５〜２倍程度の強力差が見られる）。これと比して、実施例１−１〜１−４はいずれも高い破断強力を示し、良好な接続方法であることが明らかとなった。
【００２２】
＝＝＝実施例２、比較例２＝＝＝
実施例１と同様にして補強筋を作成し、補強筋同士を単純重ね継ぎにより当接した試験片Ｂを以下のように作成し試験を行った。９２５、１０００、１０７５、１１５０ｍｍとカットした各補強筋２０同士を、単純重ね長を、３５０、５００、６５０、８００ｍｍとして接着剤で接着し、更に接着後のこれら補強筋２０を、補強片２１として前記重ね長と同じ長さのＧＦＲＰ板（実施例１に同じく、厚み１０ｍｍ、幅６０ｍｍ、４０ｍｍ幅、５０ｍｍピッチで１対のφ１１ボルト穴２１ａを設けたもの）で挟み込んだ。使用したＧＦＲＰ板のヤング率は１４００ｋｇ／ｍｍ２（１３７Ｇｐａ）である。
【００２３】
補強片２１により挟み込んだら、ボルト孔２１ａにＦＲＰボルト２２、ナット２３（Ｍ１０）を挿通させて締結した。補強片２１同士の接合面はエポキシ樹脂（商品名：アラルダイトＡＷ１０６、チバガイギー社製）にて接着し固定することとした。この実施例２における試験片Ｂの構造概要を図３（ａ）、（ｂ）に示す。引張り試験に際して、試験片Ｂの端末をエポキシ樹脂が含浸されたガラステープにて補強し、実施例１と同様の引張り強力を評価を行った。比較例２−１として、重ね長を３５０ｍｍとした例も示した。これらの引張り試験結果を表２に示す。
【００２４】
【表２】

【００２５】
実施例２−１〜２−３のいずれの試験結果も、実施例１と同様の優れた引張り破断強力を示したが、比較例２−１の結果は引張り破断強力が実施例より５０％ほど大幅に低下し満足のいくものではなかった。
【００２６】
＝＝＝実施例３、比較例３＝＝＝
実施例１と同様に、長さ７５０ｍｍにカットした補強筋３０をその端面３１で突き合わせ（端部当接過程）、この端部当接過程において当接された補強筋３０同士の少なくとも当接箇所３２上下を補強用補強筋３３（長さ５００〜８００ｍｍ）にて挟み込んだ。前記当接箇所３２と併せてこの補強用補強筋３３をエポキシ樹脂接着剤（商品名：アラルダイトＡＷ１０６、チバガイギー社製）で一体に接着し（接着過程）、更に、補強片３４として採用した長さ１５０ｍのＧＦＲＰ板（厚さ１０ｍｍ、幅６０ｍｍで、４０ｍｍ幅、５０ｍｍピッチで３対のφ１１ｍｍボルト穴３４ａを設けたもの。図４（ａ）、（ｂ）参照）で補強筋３０及び補強用補強筋３３を挟み込み、この接合面はエポキシ樹脂（商品名：アラルダイトＡＷ１０６、チバガイギー社製）にて接着する。このＧＦＲＰ板のヤング率は１４００ｋｇ／ｍｍ^２（１３７Ｇｐａ）であった。
【００２７】
つづいて、繊維強化樹脂製（或いは繊維強化熱可塑性樹脂製）のボルト３５、ナット３６（例えばサイズＭ１０）にて、上記補強片３４を通して補強筋３０及び補強用補強筋３３を一体に締結固定する（接続補強過程）。この実施例３における試験片Ｃの構造概要を図４に示す。引張り試験に際し、試験片Ｃの端末をエポキシ樹脂が含浸されたガラステープにて補強し、実施例１と同様に引張り強力を評価した。また、比較例３−１として重ね長が３５０ｍｍである場合を同様に試験した。これらの引張り試験結果を表３に示す。
【００２８】
【表３】

【００２９】
実施例３−１〜３−３のいずれの試験結果も、実施例１及び２と同様の優れた引張り破断強力を示したが、比較例３−１の結果は重ね長が短いことに由来して引張り破断強力が６０％ほど低下し満足のいくものではなかった。
【００３０】
【発明の効果】
以上詳細に説明したように、本発明の熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法は、略一方向に配列された補強繊維としての長繊維の束を熱硬化性樹脂で結着してなる芯部に、熱可塑性樹脂を被覆することで形成される炭素繊維強化プラスチック複合材を、コンクリート構造物等の補強筋として適用した熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法であって、接続する前記ＣＦＲＰ補強筋同士において、その端面を突き合わせる端部当接過程と、該端部当接過程において当接されたＣＦＲＰ補強筋同士の少なくとも当接箇所上下を所定サイズの補強用ＣＦＲＰ補強筋でカバーし、前記当接箇所と併せて接着剤で一体に接着する接着過程と、前記接着過程により互いに接着された前記ＣＦＲＰ補強筋を、該ＣＦＲＰ補強筋両側部に沿って一定間隔にてボルト穴を備える繊維強化樹脂製或いは繊維強化熱可塑性樹脂製の補強片により挟み込み、繊維強化樹脂製或いは繊維強化熱可塑性樹脂製のボルトにて、補強筋を貫通せず、補強筋の側部より一体に締結固定する接続補強過程とを備えることを特徴とする。
【００３１】
したがって、補強筋自体に高強度、高弾性率、耐腐食性、及びシールドマシンによる切削良好性を要求するＮＯＭＳＴ工法等においても、鉄製部材など在来の金属部材を使用することなく、熱可塑性樹脂被覆ＣＦＲＰ補強筋の優れた性状を余すとこなく発現できる接続方法が実現される。しかも、この接続方法を実施するにあたり、接続作業が非常に簡便であり、かつ接続後の引張り強度にも優れるといった格別な効果をも奏するのである。
【図面の簡単な説明】
【図１】本発明の熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法の第１実施例における、補強片の概要を示す説明図である。
【図２】本発明の熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法の第１実施例における、補強筋接続後の構造概要を示し、（ａ）は平面図、（ｂ）は側断面図である。
【図３】本発明の熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法の第２実施例における、補強筋接続後の構造概要を示し、（ａ）は平面図、（ｂ）は側断面図である。
【図４】本発明の熱可塑性樹脂被覆ＣＦＲＰ補強筋の接続方法の第３実施例における、補強筋接続後の構造概要を示し、（ａ）は平面図、（ｂ）は側断面図である。
【符号の説明】
１０熱可塑性樹脂被覆ＣＦＲＰ補強筋、補強筋
１１補強筋端面
１２当接箇所
１３補強用ＣＦＲＰ補強筋、補強用補強筋
１４補強片
１５ボルト[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for connecting a thermoplastic resin-coated CFRP reinforcing bar used for reinforcing inorganic structural materials such as cement mortar and concrete.
[0002]
[Prior art]
For reinforcement of inorganic structural materials such as cement mortar and concrete, rebars, wire mesh, etc. are generally used, but these iron materials are heavy and difficult to carry. There is also a problem that it is easy to rust and has only low corrosion resistance common to iron materials. For this reason, there is a big problem in the use of these iron reinforcements in the case where the cover in the concrete is thin or in a corrosive environment such as the coast.
[0003]
On the other hand, in recent years, FRP (fiber reinforced plastic), which is made of long fibers such as aramid fibers and carbon fibers that do not rust, has been attracting attention as a reinforcing material instead of the above-mentioned iron reinforcing materials. It has also been put into practical use. In particular, tension material for precast concrete (PC tension material), NOMST reinforcement in NOMST (Novel Material Shield-cuttable Tunnel-wall System) method, and rock bolt for tunnel construction, earth anchor for reinforcement of slope and ground It is being used for such as.
[0004]
As the NOMST reinforcing bar, CFRP (Carbon Fiber Reinforced Plastic) is used, which is particularly high strength, high elastic modulus, and good machinability with a shield machine cutter blade. Among them, long fibers such as carbon fiber are hardened. High-quality, rectangular CFRP bound with styrene-containing urethane acrylate resin is coated with a heat- and alkali-resistant thermoplastic resin such as polysulfone resin (PSF). It is said to be expressed (see Japanese Patent Application No. 11-165623).
[0005]
[Problems to be solved by the invention]
However, when such a thermoplastic resin-coated CFRP reinforcing bar is applied to various construction methods, there may occur a situation where the reinforcing bars must be connected to each other, for example, in the case of caisson construction. In the case of conventional reinforcing bars and the like, they can be connected relatively easily if they are welded to each other. However, a method for connecting the thermoplastic resin-coated CFRP reinforcing bars has not been sufficiently studied.
[0006]
On the other hand, in this connection work, the use of conventional metal members such as iron members is not possible due to the characteristics such as the NOMST method that requires high strength, high elastic modulus, corrosion resistance, and good cutting performance with a shield machine as described above. It is not preferable. Therefore, the connection of the thermoplastic resin-coated CFRP reinforcing bar by the connection with the material having characteristics similar to or similar to the characteristics of the reinforcing bar itself such as high strength, high elastic modulus, corrosion resistance, and good cutting performance by the shield machine. There has been a demand for the development of a connection method that can fully express its properties.
[0007]
Therefore, the present invention has been made paying attention to such a conventional problem. The connection work is simple, the tensile strength after connection is excellent, and the excellent properties of the thermoplastic resin-coated CFRP reinforcing bar. The present invention provides a method for connecting a thermoplastic resin-coated CFRP reinforcing bar that can be fully developed.
[0008]
[Means for Solving the Problems]
The present invention has been made to achieve the above object, and a thermoplastic resin is coated on a core formed by binding a bundle of long fibers as reinforcing fibers arranged substantially in one direction with a thermosetting resin. A method of connecting a thermoplastic resin-coated CFRP reinforcing bar in which a carbon fiber reinforced plastic composite formed by applying the carbon fiber reinforced plastic composite material as a reinforcing bar for a concrete structure or the like is provided. The abutting end contact process, and at least the upper and lower contact portions of the CFRP reinforcing bars abutted in the end contact process are covered with a CFRP reinforcing bar for reinforcement of a predetermined size. The bonding process of bonding together with an adhesive and the CFRP reinforcing bars bonded to each other by the bonding process are provided with bolt holes at regular intervals along both sides of the CFRP reinforcing bar. A connection that is sandwiched between reinforcing pieces made of resin or fiber reinforced thermoplastic resin, and is tightened and fixed integrally from the side of the reinforcing bar with a bolt made of fiber reinforced resin or fiber reinforced thermoplastic resin without penetrating the reinforcing bar. And a reinforcing process.
[0009]
Further, as a second invention, carbon formed by coating a thermoplastic resin on a core formed by binding a bundle of long fibers as reinforcing fibers arranged in approximately one direction with a thermosetting resin. A method of connecting a thermoplastic resin-coated CFRP reinforcing bar in which a fiber reinforced plastic composite material is applied as a reinforcing bar for a concrete structure or the like, wherein the ends of the CFRP reinforcing bars to be connected are overlapped with an appropriate lap length. An end contact process, an adhesive process in which contact portions in the end contact process are integrally bonded with an adhesive, and the CFRP reinforcing bars bonded to each other by the bonding process. A bolt made of fiber reinforced resin or fiber reinforced thermoplastic resin is sandwiched between reinforcing pieces made of fiber reinforced resin or fiber reinforced thermoplastic resin having bolt holes at regular intervals along Te, without penetrating the reinforcement, characterized in that it comprises a connection reinforcement process of fastened together from the sides of the reinforcement.
[0010]
The reinforcing piece made of fiber reinforced resin or fiber reinforced thermoplastic resin preferably has a Young's modulus (elastic modulus) of, for example, 9.8 Gpa (1000 kg / mm ² ) or more, and is smaller than this value. When the bolts are tightened, the pressure is biased around the bolt holes and the tightening effect is reduced. The thickness of the member is preferably 20 mm or less from the viewpoint of workability. The material of the reinforcing piece is not limited to CFRP or the like, but GFRP (Glass Fiber Reinforced Plastic) or the like can be appropriately selected from the viewpoint of cost, rigidity, and strength.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
=== Example 1 ===
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0012]
(1) Production of thermoplastic resin-coated CFRP reinforcing bars Polysulfone (trade name: Polysulfone P1700BK937, manufactured by Teijin Amoco Co., Ltd.) is used as a coating resin for coating a bundle of long fibers, and the thickness is 5.5 mm and the width is 20.3 mm. A CFRP reinforcing bar (hereinafter referred to as FTC) having a thickness of 4.0 mm and a width of 19.0 mm was manufactured as follows. This manufacturing process is not particularly illustrated.
[0013]
First, 50 carbon fibers (trade name: Torayca T-700SC 24K, manufactured by Toray Industries, Inc.) are supplied from a stand, and the resin material (trade name: Iupika 8921, manufactured by Nippon Iupika Co., Ltd.) and a temperature of 10 hours half-life 4 parts of a catalyst (trade name: Kadox B-CH50, manufactured by Kayaku Akzo Co., Ltd.) at 72 ° C. and a catalyst (product name: Kayabutyl B, Kayaku Akzo Co., Ltd.) having a 10 hour half-life temperature of 105 ° C. 0.5 part) is added and mixed to form a urethane acrylate resin, which is impregnated into the carbon fiber in an impregnation tank.
[0014]
Subsequently, excess resin is gradually squeezed out with a squeezing nozzle to make the cross section rectangular (vertical and horizontal 4 × 19 mm, fiber content 58.5 vol%), which is led to a crosshead die, and the polysulfone is extruded into an annular shape and coated did. After cooling with room temperature water immediately after the coating point, it is cured in a hot water curing tank (95 to 99 ° C.) having a total length of 8.5 m and a dry heat curing furnace (total length 8 m, 100 to 120 ° C.) using a hot air generator.
[0015]
The take-off speed in the above process was 2.5 m / min, and after the curing, the coating surface was embossed. This embossing is performed at a roller temperature of 330 ° C. using a dry heat curing furnace as preheating (150 to 160 ° C.). The thermoplastic resin-coated CFRP reinforcing bars (hereinafter simply referred to as reinforcing bars) were cut to 1500 mm, and the end portions were reinforced by wrapping a glass tape impregnated with an epoxy resin and cured at room temperature for 24 hours. . After hardening, the reinforcing bars were subjected to a tensile test using an Amsler type tensile tester (not shown) with a load of 100 tons, and the tensile strength was 19.0 tf (186 kN). Hereinafter, this Amsler type tensile tester is used for the tensile test.
[0016]
(2) Preparation of bonded product and tensile strength of bonded portion Next, as described below, a test piece A was prepared in order to test the tensile strength of the reinforcing bars connected by the connection method of the present invention.
[0017]
The reinforcing bars 10 cut to a length of 750 mm are butted at the end face 11 (end contact process), and at least the upper and lower contact points 12 of the reinforcing bars 10 contacted in the end contact process are reinforcing reinforcing bars. 13 (length: 500 to 950 mm). Following this pinching operation, the reinforcing reinforcing bars 13 are bonded together with an epoxy resin adhesive (trade name: Araldite AW106, manufactured by Ciba Geigy) together with the contact portion 12 (bonding process). GFRP plate of the same length as the reinforcing reinforcing bar 13 adopted as 14 (thickness 10 mm, width 60 mm, 40 mm width, 50 mm pitch and a pair of φ11 mm bolt holes 14a, see FIG. 1). 10 and the reinforcing reinforcing bars 13 are sandwiched. The Young's modulus of this GFRP plate was 1400 kg / mm ² (137 Gpa).
[0018]
Then, the reinforcing bar 10 and the reinforcing bar 13 for reinforcement are integrally fastened and connected through the reinforcing piece 14 with bolts 15 and nuts 16 (for example, size M10) made of fiber reinforced resin (or fiber reinforced thermoplastic resin). Reinforcement process). The bolt fastening torque at this time is preferably 15 Nm to 20 Nm, and the arrangement interval of the bolt holes 14a is preferably about 20 to 100 mm.
[0019]
An outline of the structure of the test piece A prepared as described above is shown in FIGS. In the tensile test, the end of the test piece A was reinforced with a glass tape impregnated with an epoxy resin for evaluation. Tensile test results at each overlap length were obtained by changing the overlap length of the reinforcement reinforcing bars 13 and the reinforcement bars 10 to 500 mm to 950 mm (Examples 1-1 to 1-4). On the other hand, as a comparative example, two types of overlap lengths of 500 mm and 650 mm were set, and the test was similarly performed by changing the bolt pitch and bolt tightening torque (Comparative Examples 1-1 to 1-6). These test results are shown in Table 1.
[0020]
[Table 1]

[0021]
Comparative Example 1-1 had a shorter overlap length than the other Examples and Comparative Examples, and Comparative Examples 1-2 and 1-3 had a lower breaking strength because the bolt tightening interval was wider than the others. In Comparative Example 1-4, no adhesive was used, in Comparative Example 1-5, no bolting, and in Comparative Example 1-6, the breaking strength was remarkably reduced due to insufficient bolt tightening force (Comparative Example). And the test results of the examples show a strength difference of about 1.5 to 2 times). Compared to this, Examples 1-1 to 1-4 all showed high breaking strength, and it became clear that they were good connection methods.
[0022]
=== Example 2, Comparative Example 2 ===
Reinforcing bars were prepared in the same manner as in Example 1, and a test piece B in which the reinforcing bars were in contact with each other by a simple lap joint was prepared and tested as follows. The reinforcing bars 20 cut to 925, 1000, 1075, and 1150 mm are bonded with an adhesive with a simple overlap length of 350, 500, 650, and 800 mm. Further, these reinforcing bars 20 after bonding are used as reinforcing pieces 21. It was sandwiched between GFRP plates having the same length as the overlap length (as in Example 1, with a pair of φ11 bolt holes 21a provided at a thickness of 10 mm, a width of 60 mm, a width of 40 mm, and a pitch of 50 mm). The Young's modulus of the GFRP plate used is 1400 kg / mm 2 (137 Gpa).
[0023]
When sandwiched by the reinforcing piece 21, the FRP bolt 22 and the nut 23 (M10) were inserted into the bolt hole 21a and fastened. The joining surfaces of the reinforcing pieces 21 are bonded and fixed with an epoxy resin (trade name: Araldite AW106, manufactured by Ciba Geigy Corporation). An outline of the structure of the test piece B in Example 2 is shown in FIGS. In the tensile test, the end of the test piece B was reinforced with a glass tape impregnated with an epoxy resin, and the same tensile strength as in Example 1 was evaluated. As Comparative Example 2-1, an example in which the overlap length was 350 mm was also shown. Table 2 shows the results of these tensile tests.
[0024]
[Table 2]

[0025]
Although all the test results of Examples 2-1 to 2-3 showed the same excellent tensile breaking strength as that of Example 1, the results of Comparative Example 2-1 showed that the tensile breaking strength was about 50% of the examples. It was significantly lower and not satisfactory.
[0026]
=== Example 3, Comparative Example 3 ===
Similar to the first embodiment, the reinforcing bars 30 cut to a length of 750 mm are butted at the end face 31 (end contact process), and at least the contact points of the reinforcing bars 30 that are contacted in the end contact process. 32 The upper and lower sides were sandwiched by reinforcing bars 33 (length: 500 to 800 mm). Along with the contact portion 32, the reinforcing reinforcing bar 33 is integrally bonded with an epoxy resin adhesive (trade name: Araldite AW106, manufactured by Ciba Geigy Co., Ltd.) (adhesion process). 150m GFRP plate (Thickness 10mm, Width 60mm, 40mm Width, 50mm Pitch with 3 pairs of φ11mm bolt holes 34a. See Fig. 4 (a) and 4 (b)). The joint 33 is sandwiched with an epoxy resin (trade name: Araldite AW106, manufactured by Ciba Geigy). The Young's modulus of this GFRP plate was 1400 kg / mm ² (137 Gpa).
[0027]
Subsequently, the reinforcing bar 30 and the reinforcing reinforcing bar 33 are integrally fastened and fixed through the reinforcing piece 34 with a bolt 35 and a nut 36 (for example, size M10) made of fiber reinforced resin (or fiber reinforced thermoplastic resin). (Connection reinforcement process). An outline of the structure of the test piece C in Example 3 is shown in FIG. In the tensile test, the end of the test piece C was reinforced with a glass tape impregnated with an epoxy resin, and the tensile strength was evaluated in the same manner as in Example 1. Moreover, the case where the overlap length was 350 mm was similarly tested as Comparative Example 3-1. Table 3 shows the results of these tensile tests.
[0028]
[Table 3]

[0029]
All the test results of Examples 3-1 to 3-3 showed the same excellent tensile fracture strength as in Examples 1 and 2, but the result of Comparative Example 3-1 was derived from the short overlap length. As a result, the tensile strength at break was reduced by about 60%, which was not satisfactory.
[0030]
【The invention's effect】
As described above in detail, the method for connecting the thermoplastic resin-coated CFRP reinforcing bars of the present invention is a core formed by binding a bundle of long fibers as reinforcing fibers arranged in substantially one direction with a thermosetting resin. A CFRP reinforcing bar connecting method in which a carbon fiber reinforced plastic composite formed by coating a thermoplastic resin on a part is applied as a reinforcing bar for a concrete structure or the like, and the CFRP to be connected The reinforcing bars are covered with an end abutting process in which the end faces abut each other, and at least the upper and lower contact portions of the CFRP reinforcing bars abutted in the end abutting process are covered with a CFRP reinforcing bar of a predetermined size. The bonding process of bonding together with the contact portion with an adhesive and the CFRP reinforcing bars bonded to each other by the bonding process are fixed along both sides of the CFRP reinforcing bars. It is sandwiched between reinforcing pieces made of fiber reinforced resin or fiber reinforced thermoplastic resin having bolt holes at intervals, and does not penetrate the reinforcing bar with bolts made of fiber reinforced resin or fiber reinforced thermoplastic resin. And a connection reinforcing process for fastening and fixing integrally from the side portion.
[0031]
Therefore, in the NOMST method that requires high strength, high elastic modulus, corrosion resistance, and good cutting performance with a shield machine for the reinforcing bar itself, a thermoplastic resin can be used without using conventional metal members such as iron members. A connection method that can fully express the excellent properties of the coated CFRP reinforcing bar is realized. Moreover, in carrying out this connection method, the connection work is very simple, and there is an extraordinary effect that the tensile strength after connection is excellent.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an outline of a reinforcing piece in a first embodiment of a method for connecting a thermoplastic resin-coated CFRP reinforcing bar of the present invention.
FIGS. 2A and 2B show an outline of the structure after connecting reinforcing bars in the first embodiment of the connecting method of the thermoplastic resin-coated CFRP reinforcing bars of the present invention, FIG. 2A is a plan view, and FIG. 2B is a side sectional view; .
FIGS. 3A and 3B show an outline of a structure after connecting reinforcing bars in a second embodiment of the method for connecting a thermoplastic resin-coated CFRP reinforcing bar of the present invention, FIG. 3A is a plan view, and FIG. 3B is a side sectional view; .
FIGS. 4A and 4B show an outline of the structure after connecting reinforcing bars in a third embodiment of the connecting method of the thermoplastic resin-coated CFRP reinforcing bars according to the present invention, FIG. 4A is a plan view, and FIG. .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Thermoplastic resin coated CFRP reinforcing bar, reinforcing bar 11 Reinforcing bar end face 12 Contact point 13 Reinforcing CFRP reinforcing bar, reinforcing reinforcing bar 14 Reinforcing piece 15 Bolt

Claims

A carbon fiber reinforced plastic composite formed by coating a thermoplastic resin on a core formed by binding a bundle of long fibers as reinforcing fibers arranged in approximately one direction with a thermosetting resin, A method of connecting a thermoplastic resin-coated CFRP reinforcing bar applied as a reinforcing bar for a structure or the like,
A CFRP reinforcement for reinforcement of a predetermined size at an end part contact process in which the end surfaces of the CFRP reinforcement bars to be connected are abutted, and at least a contact portion between the CFRP reinforcement bars abutted in the end part contact process. An adhesive process of covering with a streak and integrally bonding with an adhesive together with the contact portion, and the CFRP reinforcing bars bonded to each other by the adhesive process at regular intervals along both sides of the CFRP reinforcing bar It is sandwiched between reinforcing pieces made of fiber reinforced resin or fiber reinforced thermoplastic resin with bolt holes, and does not penetrate the reinforcing bar with the bolt made of fiber reinforced resin or fiber reinforced thermoplastic resin, from the side of the reinforcing bar A method of connecting a thermoplastic resin-coated CFRP reinforcing bar, comprising a connection reinforcing process for fastening and fixing together.

A carbon fiber reinforced plastic composite formed by coating a thermoplastic resin on a core formed by binding a bundle of long fibers as reinforcing fibers arranged in approximately one direction with a thermosetting resin, A method of connecting a thermoplastic resin-coated CFRP reinforcing bar applied as a reinforcing bar for a structure or the like,
In the CFRP reinforcing bars to be connected, an end part contact process in which end parts are overlapped with an appropriate lap length, an adhesive process in which the contact part in the end part contact process is integrally bonded with an adhesive, The CFRP reinforcing bars bonded to each other by the bonding process are sandwiched by reinforcing pieces made of fiber reinforced resin or fiber reinforced thermoplastic resin having bolt holes at regular intervals along both sides of the CFRP reinforcing bar, and the fiber reinforced resin A thermoplastic resin-coated CFRP reinforcing bar comprising a connection reinforcing process in which bolts made of fiber or fiber reinforced thermoplastic resin do not penetrate the reinforcing bar and are fastened and fixed integrally from the side of the reinforcing bar Connection method.