Experimental Study on Bond-Slip Behavior of Steel Reinforcement in High-Strength Strain-Hardening Cementitious Composites (SHCC) Under Direct Tension

Strain-hardening cementitious composites (SHCC) are pseudo-ductile materials with remarkably high tensile ductility and excellent crack control capability. In some promising applications of SHCC (e.g., construction of structural joint between pre-cast reinforced concrete components), good bonding between SHCC and rebars is essential to ensure sufficient stress transfer. However, the present understanding on the bond between high-strength SHCC and steel rebars is limited. This paper presents an experimental investigation on the bond property between deformed rebars and high-strength SHCC under direct tension. High-strength SHCC with compressive strength of 112 MPa, tensile strength of 8.6 MPa, and tensile strain capacity of 5.5% was used. Steel rebars with three different diameters of 20, 25 and 32 mm, as well as three different cover-to-rebar diameter (C/D) ratios of 1, 1.5, and 2 were examined. The effects of rebar diameter and cover thickness on the bond-slip behavior of steel rebars in high-strength SHCC were discussed. The results showed a significantly improved bonding characteristics between SHCC and deformed steel rebars in comparison to concrete. The bond strength generally increases with an increasing C/D ratio but may stay constant beyond a certain cover thickness. The findings of this study can hopefully improve the current understanding of bonding characteristics of SHCC with deformed steel rebars and can facilitate the structural design of reinforced SHCC members.