Effect on the pull out and the bond strength of concrete by different surface treatment of steel reinforcement bars

In present research, it is aimed to study the effect of different interface of steel reinforcement bars on the pull out and bond strength of the concrete. The concrete possess a good compressional strength but relatively low pull out strength. So to enhance its pull out strength different reinforcements like steel bars, wires etc. are introduced in the concrete. The introduced steel bars give good pull out properties to concrete but also affected in corrosive environment. Different interface is made to protect these bars from corrosion by applying different treatment on the interface between surrounding concrete and steel bars which affects the bond strength between concrete and the re-bar. Reinforced bars are surface treated with emulsion paint, polyester resin, alkali and lubricating oil. Ravi and Chenab sand are used to produce two different concrete, having the compressional strength of 24.37 MPa and 19.25 MPa respectively. Pull out testing to find out the pullout strength which is further used to calculate the bond strengths. The results shows that both types of concrete specimens possess the maximum pull out and bond strength for untreated reinforcement bars The specimens with painted reinforcement bars has the minimum pull out and bond strength among all the specimens. The ravi sand has pull out strength of 5kN and 3kN for untreated and paint surface treated respectively while chenab sand has pull out strength of 7.5kN and 2.5kN for untreated and paint surface treated respectively.