Two‐dimensional rib‐scale simulation of the bond‐slip mechanism between rebars and recycled aggregate concrete

Abstract The bond‐slip behavior between rebars and recycled aggregate concrete is of crucial importance. This study proposed a two‐dimensional rib‐scale simulation method that did not rely on measured bond strength and could reflect the passive confinement effect during the pull‐out process. The method was validated on two representative specimens, yielding ultimate bond‐strength errors of 2.27% and 9.29%. In addition, a rapid parametric software tool was developed, and the evolution of interface damage was studied through parametric analysis. The results show that: (1) compressive damage initiates ahead of the rib at the loading end, forming a wedge‐shaped crushing zone at an angle of 45°–75°, while tensile damage arises from vertical cracks above the rib. The passive confinement force attenuates in a wave‐like pattern along the rebar. (2) Increasing rib spacing reduces bond strength and alters the continuity of damage patterns; the rib side angle exhibits little sensitivity within 45°–75°, whereas at 85° bond strength deteriorates sharply, with localized damage extending from the rib tip to the rib root; increasing rib height raises the peak bond strength (with the most pronounced gains at 1.2–1.7 mm), but accelerates post‐peak degradation; increasing the recycled aggregate replacement ratio leads to only a slight decrease in peak strength (about 1%–1.6% per 20% increase in replacement ratio). (3) Within the explored ranges, rib geometry has a more significant influence on bond strength than the replacement ratio. This paper provides insights for refined structural simulation.