Experimental Tests to Study the Influence on the Shear Behavior of Fibers of Different Characteristics - On Shear Behavior of Structural Elements Made of Steel Fiber Reinforced Concrete - page 102

Chapter 6
Experimental Tests to Study the Influence
on the Shear Behavior of Fibers
of Different Characteristics

6.1 Introduction

Steel ber reinforced concrete (SFRC) is a composite material that is characterized

by an enhanced post-cracking behavior due to the capacity of bers to bridge the

crack faces. The enhanced toughness is mainly provided by bond and high-modulus

bers are more effective than straight
and crimped ones in enhancing the post-peak energy absorption capacity. The effect
of

bers in a suitable concrete matrix. Hooked

ber types seem
to act similarly in this regard [ 1 ]. Bencardino et al. [ 2 ] realized that the addition of
steel

bers on compressive strength is relatively small, and different

cantly
improves the post-peak behavior. In 2014, Banthia et al. [ 3 ] has ensured that, in
mixes reinforced with a single

bers with high aspect ratio into a high strength concrete matrix signi

ber, the Hooked-End ber was signi cantly better

in shear than the Double Deformed ber.

On the other hand, the inclusion of bers decreases the concrete workability.

This effect is more pronounced for bers with higher aspect ratios.

uence shear behavior and shear
capacity guarantying the minimum shear reinforcement required by the current
Codes. SFRC makes possible a more distributed cracking pattern, where shear
cracks are characterized by smaller crack spacing and widths [ 4 ].
Many studies have advanced the knowledge in shear behavior of FRC beams.
Fiber content has a signi

Steel bers in concrete can considerably in fl

ber type was also
found to be influential since both of them influence the FRC toughness. Fibers with
a higher aspect ratio resulted in an increased shear strength due to the enhanced
post-cracking behavior compared to

cant effect on shear behavior, but the

bers with a low aspect ratio [ 2 , 5 7 ]. Hooked

-

steel bers with a length of 60 mm allowed a larger shear crack opening when

compared to that observed in beams with 30 mm long bers, but they were prone to

problems associated with ber lumping along the longitudinal reinforcement. In

fact, horizontal clear spacing between reinforcing bars, no less than the

ber length,

is recommended [ 8 ].