Title:
Hooking Effect on Flexural Strength and Toughness of Steel Fiber-Reinforced Concrete Beams
Author(s):
S. H. Chu, L. Sneed, D.-Y. Yoo, and A. K. H. Kwan
Publication:
Materials Journal
Volume:
121
Issue:
6
Appears on pages(s):
15-26
Keywords:
end hooks; flexural strength; hooking effect; steel fiberreinforced concrete (SFRC); steel fibers; toughness
DOI:
10.14359/51743281
Date:
12/1/2024
Abstract:
End hooks of steel fibers provide a stronger bridging force across
the concrete matrix in steel fiber-reinforced concrete (SFRC). In
this work, SFRC beams were prepared with steel fibers of the same
length and diameter but different types of end hooks (straight,
three-dimensional [3D], four-dimensional [4D], and fivedimensional [5D]) at increasing fiber volumes (0.0, 0.5, 1.0, 1.5,
and 2.0%). Four-point bending tests conducted on each SFRC
beam yielded load-deflection curves, from which the first cracking
strength, flexural strength, and fracture toughness up to certain
deflection-to-beam length ratios were obtained. The test results
showed that the presence of end hooks remarkably enhanced
the flexural strength and toughness of the SFRC beams, and this
enhancement was amplified with an increasing number of hooks.
Quantitative analysis revealed the hooking index, a factor introduced herein to delineate the efficiency of various types of hooks, was 1.00, 1.30, 1.60, and 2.10, respectively, for straight, 3D, 4D, and 5D steel fibers used in the present study. Lastly, empirical
models for predicting flexural strength and toughness were established with high prediction accuracy.