BOND CHARACTERISTICS OF DEFORMED REINFORCING STEEL BARS EMBEDDED IN SIFCON

The bond-versus-slip characteristics of deformed reinforcing steel bar s embedded in slurry-infiltrated fiber concrete (SIFCON) were determin ed for different values of bar embedment length, net concrete cover, c ompressive strength of SIFCON, and bar diameter. Measurements included bar tension force, slip at free and loaded ends of the bar, and steel and concrete strain distributions along the bar embedment length. Cra ck patterns were monitored and modes of bond failure were observed. It is observed that SIFCON leads to a significant increase in average bo nd stress, bond stiffness, and pullout work of bars when compared not only to plain concrete but to highly confined concrete. Average bond s tresses as high as 2500 psi (17.25 MPa) were measured, while maximum p ullout forces were maintained for slips 10 times larger than those obs erved for plain concrete. The initial bond stiffness was 250 and 150 p ercent that of plain and confined concrete, respectively, while total pullout work was more than twice and 20 times that observed for plain and confined concrete, respectively. Everything else being equal, the average bond stress of reinforcing steel bars embedded in SIFCON incre ased with an increase in the compressive strength of SIFCON and the co ncrete cover and decreased with an increase in bar diameter.