The Influence of Interlock Loss between Rebar and Concrete on Bond Performance of RC Member

Abstract

Rebar corrosion, which causes section loss of rebar, is one of the serious deterioration factors for RC structures. Section loss affects not only stiffness or load capacity but also interlock condition between lugs on deformed rebar and surrounding concrete. Interlock is a dominant factor of bond between rebar and concrete and interlock effects on structural behavior of RC member can be significant. This research focused on the influence of interlock loss on the structural behavior and bond performance of RC member from experimental and analytical investigations. The static loading test for the six beams and FE analysis were conducted for the investigation on the effects of residual interlock, with or without confinement effects from stirrups. In order to evaluate interlock effects precisely, a rebar shape including lugs was reproduced by fine hexahedron elements in the FE analysis. The authors also conducted FE analytical case studies for investigating the effects of non-uniform lug loss or partially interlocking condition due to section loss of rebar. Through these investigations, it was seen that interlock could work and keep sound bond as long as contact between a lug and concrete was maintained even when the rebar lug was flattened due to section loss. Furthermore, under the situation with non-uniform distribution of section loss, pull-out behavior of rebar was prevented by interlocking of parts in a member even when other regions completely lost their interlock due to serious section loss.

Keywords

• bond deterioration
• interlocking
• section loss
• rebar corrosion
• deformed bar