Abstract
Cracking in reinforced concrete structures is of major concern since it may affect their durability and structural integrity. Cracking is mainly influenced by stress distribution along the interface between steel and concrete which is responsible of transferring load from steel bar to the surrounding matrix. Thus, quantitative evaluation of steel-concrete bond effect on fracture properties is important. An experimental investigation on Reinforced Concrete (RC) ties is reported in this paper. Pull-out and tensile tests have been conducted on cubic specimens with high adhesion reinforcement bars with different diameters in parallel with a continuous monitoring using the Acoustic Emission (AE) and the Digital Image Correlation (DIC) techniques. Two failure modes have been observed according to the steel bar section: concrete cover splitting and pull out with damage concentrated near the concrete rebar interface. The results show a good correlation between the loading force and the AE activity with AE signal of different characteristics indicating different active fracture mechanisms. The order of appearance of cracks, their width and their spacing have been also measured in correlation with the loading level for short ties with different lengths and bar diameters.
Highlights
During last years, many bridges and Reinforced Concrete (RC) structures have collapsed all over the world due to aging
The behavior of short ties under tensile tests can be decomposed in three phases: an elastic linear phase; a phase of development of cracking characterized by a progressive increase of cracks along the tie rod and a decrease in structural rigidity; a stabilized cracking phase for which the behavior of the tie rod is governed by the behavior of the steel
The present research study allows to analyze the characteristics of Acoustic Emission (AE) hits generated during pull-out and tensile tests of RC ties
Summary
Many bridges and Reinforced Concrete (RC) structures have collapsed all over the world due to aging. Bond-slip between reinforcement and concrete is characterized by three main components: chemical adhesion, mechanical interaction, and friction. The chemical adhesion breaks down first for low bond stress values where no slip between the reinforcement and the concrete is observed. For higher bond stress values, the limited wedging action of the lugs causes transverse microcracks which allow the bar to slip. In a bar pull-out failure, the wedging action is enhanced, and hoop stresses appear at the surrounding concrete, which at the same time exerts a confinement action on the bar. Splitting cracks are present in concrete cover due to the radial pressure induced by the ribs of stressed bars. A recent study conducted by Mezhoud et al [18] proposed new relationships for the characteristic values of the bond - slip law based on the same pull-out tests, and the behavior of short tie rods has been deduced
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
