Effect of Contamination on Reinforcing Bar-Concrete Bond

Abstract

Current specifications require the removal of reinforcing bar contaminants that reduce bond prior to placing concrete. This study focused on the interactions of contaminant type, bar size, epoxy coating, concrete strength, and test method (beam and direct pullout). The majority of the beam tests showed the bond strength was not significantly affected, with certain exceptions. However, the direct pullout tests revealed a significant reduction of bond strength in most situations. Although the bond strength was still greater than that required by code, it is recommended that specifications for removal of contaminants should not be relaxed until further study is performed.