Bond Stress-Slip Behavior of Hybrid Fiber-Reinforced Recycled Aggregate Concrete Using Beam Test

This paper presents an experimental investigation of bond stress-slip behavior of steel bars embedded in mono and hybrid fiber-reinforced recycled aggregate concrete. The main study parameters investigated were type of fibers and their dosage in terms of volumetric fraction. Crimped steel fibers and polypropylene fibers were used in mono and hybrid forms at two different volume fractions of 0.25 and 0.50%. Beam and cylinder specimens were cast and tested to investigate the bond stress-slip behavior and compressive strength of concrete, respectively. Experimental results depicted that partial replacement of natural aggregates with recycled aggregates showed negative impact on maximum bond strength of concrete. However, overall bond stress-slip behavior was similar for both natural aggregate concrete and recycled aggregate concrete. Addition of crimped steel fibers at 0.5% in mono form and polypropylene and steel fibers at 0.25% each in hybrid form showed significant improvement in bond strength and bond toughness of steel bars embedded in recycled aggregate concrete.