合成短繊緎の付着特性が補強コンクリートの曲げ特性に与える影響に関する研究

摘要

The bending properties of synthetic fiber reinforced concrete were evaluated from the standpoints of bending strength and bending toughness coefficient based on the results of bending tests. In addition, bond properties between fibers and matrix were evaluated with regards bond strength and bond toughness coefficient as results of fiber bond tests. Polyvinyl alcohol (PVA) fiber had strong chemical bonds with matrices, resulting in high bending strength of fiber reinforced concrete. The chemical bond, however, was lost in large deflection zone during load applying stage, and the pullout load reduced greatly. Consequently, both the bond toughness coefficient of fibers and bending toughness coefficient of fiber reinforced concrete were also decreased. Though the bond strength of polyethylene & polypropylene monofilament (PE&PP) fiber was lower compared to PVA fiber, PE&PP fiber showed higher bond toughness coefficient. It was reasoned that the surface area per unit volume of PE&PP fiber was actually larger. As a result, the bending toughness coefficient of PE&PP fiber reinforced concrete was also higher. It was clearly shown that the bond properties of fibers strongly influence on the bend properties of fiber reinforced concrete.%合成短繊維の付着特性と補強マトリックスの曲げ特性に関して実験により検討を行った。曲げ特性では曲げ試 験によって曲げ強度と曲げじん性係数を求め，また，繊維とマトリックスの付着特性は付着試験によって付着強度と 付着じん性係数を求めた。実験結果により，マトリックスとの間に強いケミカル結合を有するビニロン繊維は付着強 度が高く補強マトリックスの曲げ強度も高い値であったが，すべり量が増加するとケミカル結合が喪失し引抜き荷重 の低下が大きくなるため，付着じん性係数や曲げじん性係数は低い値となった。一方，ポリエチレン・ポリプロピレ ン系のブレンドモノフィラメント繊維の付着強度は低いが，単位体積あたりの表面積が大きいために付着じん性係数 は高くなり，補強マトリックスの曲げじん性係数も高い値であった。すなわち，繊維の付着特性が補強マトリックス の曲げ特性に影響を及ぼすことを明らかにした。