Effect of Rib Spatial Distribution on Bond Behavior between Steel and Concrete using 3D Meso-scale Model

Abstract

The spatial distribution of crescent ribs and the multiphase properties of concrete make it difficult to predict the bond behavior between steel and concrete. The crescent ribs on the surface of rebar are explicitly simulated at meso-scale, which are stretched out along the trajectory and merged into the rebar. A multiphase concrete model is built, composed of mortar, aggregate, and interface layer (ITZ). The interaction model between ribbed bars and concrete is established considering the frictional and mechanical interaction. The effects of rib spatial distribution, aggregate content and stirrup ratio on bond performance are discussed. The results show that the bond strength of the transverse ribs arranged in the opposite direction is much higher than that in the same direction, but adding longitudinal ribs or increasing the inclination angle of transverse rib can reduce this effect. The sensitivity of bond strength on rib height is greater than that on rib spacing and rib inclination angle. The bond performance of steel first increases and then decreases with the increase of aggregate content. Excessive aggregate content makes the concrete brittle and reduces bond ductility. The constraint effect of stirrup on splitting failure of beams is more significant than that on pull-out failure.