インデント型鋼繊維の引抜抵抗に関する研究

1.はじめに

2.試験片と試験方法

  2・1 試験片

  2・2 試験方法

3.試験結果

 3.1 モルタルの力学試験結果

 3.2 引抜抵抗曲線

 3.3 最大引抜抵抗と引抜エネルギー

4.引抜特性と一軸引張試験結果との関係

 4.1 一軸引張試験における最大残留強度

 4.2 一軸引張試験における残留強度と変位の関係

5.まとめ

引用文献

キーワード: 鋼繊維,インデント,モルタル,引抜試験,定変位速度,引抜抵抗,一軸引張強度


Study on Pullout Resistance of Indent-Type Steel Fiber

Abstract

Steel fiber reinforced mortar (SFRM) or concrete (SFRC) is one of the future promising composite materials and suits, for example, today's rapid excavation by a tunnel boring machine, a boom header or a continuous miner.

It is well known that SFRM is improved in toughness and crack resistance mainly by the pullout resistance of steel fibers. Though some pullout tests have been published, fundamental data concerning pullout resistance are still insufficient.

In this study, pullout tests were conducted pulling an indent-type steel fiber out of the mortar sample at a constant displacement rate by a servo-controlled testing machine. It was found that load-displacement curves obtained experimentally were not smooth with complicated shapes especially in the post-failure region (region after the maximum pullout resistance). The curves were classified into four patterns depending on the shapes. For every pattern, the maximum pullout resistance and the total pullout energy necessary to pull the steel fiber out of the mortar sample were obtained. Finally, the correlation between the maximum pullout resistance and the tensile strength of SFRM were discussed.

Key Words: Steel Fiber, Indent, Mortar, Pullout Test, Constant Displacement Rate, Pullout Resistance, Uniaxial Tensile Strength