Ring test for evaluation of bond properties of reinforcing bars

Abstract

ABSTRACTA pull-out bond test with short bond length for estimation of the splitting tendency of different rib shapes for reinforcing bars is proposed and investigated. In the test the bond force component along the bar is separated from the radial one. The radial component is determined by measuring circumferential strain in a steel ring surrounding the concrete of the pull-out specimen. The force component, which is longitudinal to the bar, is obtained by supporting the pull-out specimen with a teflon covered circular support close to the bar. Bars with specially turned ribs are studied concerning rib height and rib distance. Swedish standard high bond bars are also studied. The splitting tendency is stated as a function of the slip of the free bar end and also of the related rib area of the bars.