Experimental investigation on influence of embedment length, bar diameter and concrete cover on bond between reinforced bars and steel fiber reinforced concrete (SFRC)

The bond between reinforced bars and concrete has a significant impact on reinforced concrete structures. Incorporating steel fibers in concrete not only enhances the performance of the concrete but also influences the bond strength of embedded reinforcing bars. In this paper, experiments have been carried out to investigate the influences of different bar diameters, concrete cover and embedment lengths on bond-slip responses between reinforcing bars and steel fiber reinforced concrete (SFRC). Furthermore, pull-out tests with normal concrete were also executed as a comparative group. The bond-slip results of specimens were collected. The impact of embedment length, reinforcing bar diameter, and the existence of steel fibers on the bond behavior of reinforcing bars was comprehensively analyzed. Meanwhile, the results indicate that variations in the ratio of concrete cover to reinforcing bar diameter lead to different effects on the bond behavior of SFRC compared with normal concrete. Different failure modes of specimens were exhibited and discussed. Additionally, a mathematical model for bond strength of bars in SFRC was proposed based on the correction of the bond strength model with normal concrete, which shows good agreement with experimental results.