Pullout Behaviour of Steel Under Different Types of Concrete Composites

In reinforced-concrete members adequate bond strength between reinforcing bars is necessary to guarantee full composite action. The present study involves the analysis of bond strength by conducting pullout test on deformed steel rebar embedded in various types of concrete such as normal concrete, engineered cementitious composite (ECC) and glass powder concrete (GPC). ECC has ductility due to presence of fibre which prevents development of internal cracks, and it has more compatible deformability with steel rebar. The bond between concrete and steel is not uniform and differ with different loading condition. Other factors like mechanical interlocking, adhesion between concrete and steel also contribute to bond. Earthquake forces causes reversal of load and hence at lap joints it can cause slip of the joints if sufficient anchorage length is not given. Pullout studies were conducted to assess the bond characteristics of concrete and steel using cube and cylindrical specimens as per the current standards/codes. The bond slip behavior acquired from the pullout test using the software "ANSYS" were equated with the experimental results. The bond strength of ECC and GPC are more compared to that of M30 using same strength of concrete composites. All load-slip curves have mostly the same trend for M30, GPC and ECC. Comparison of numerical results with experimental results gave less than 6% error for concrete composites. From both experimental and numerical studies, failure is more critical at the interface region of concrete composites and steel bar.