Abstract
The use of steel fiber reinforced concrete (SFRC) is becoming more and more common. Concerning bond
of rebars to concrete, fibers provide passive confinement and not only improve bond performance but
also affect the mode of bond failure. To analyze these aspects, a series of prismatic specimens have been
subjected to the Pull Out Test, and an accurate model for predicting the mode of bond failure has been
developed. The following factors have been considered: concrete compressive strength (3050 MPa),
rebar diameter (820 mm), concrete cover (between 30 mm and 5 times rebar diameter), fiber content
(up to 70 kg/m3), and fiber slenderness and length. This model relates splitting probability to the factors
considered. It has been proved that increasing fiber content restrains the risk of splitting failure. The
favorable effect of fibers when preventing splitting failures has been revealed to be more important for
higher concrete compressive strength values, which require higher concrete cover/diameter ratios for
splitting failure to be prevented. Fiber slenderness and fiber length modify the effect of fiber content
on splitting probability and therefore on minimum cover/diameter ratios required to prevent splitting
failures.