Bond behavior between shaped steel and high strength self-compacting concrete

The bond behavior between shaped steel and high strength self-compacting concrete is crucial for ensuring the collaborative behavior of these two materials. This bond behavior serves as the foundation for the effective interaction and structural integrity of steel-concrete composite systems. Given the increasing use of shaped steel reinforced high strength self compacting concrete in modern high-rise building construction, understanding the bond behavior is essential for improving the design of steel-concrete structures. To investigate the bond behavior at the interface between the shaped steel and high-strength self-compacting concrete, nine specimens were designed and fabricated, varying the thickness of the concrete cover and the embedded length of the shaped steel. Push-out tests were conducted to observe the failure process and patterns of the specimens. The complete load-slip curves at the loading end were obtained, and the effects of different variables on bond strength were analyzed. The results indicate that the ultimate bond strength increases with the thickness of the concrete cover, with a maximum increase of 94.9%. Conversely, the ultimate bond strength decreases with the increase of the embedded length of the shaped steel, with a maximum reduction of 38.1%. The interfacial bond shear stiffness initially increases and then decreases with increasing concrete cover thickness, with a maximum increase of 85.1%. As the embedded length of the shaped steel increases, the bond shear stiffness also increases, with a maximum rise of 30.0%. With thicker concrete cover, the development of interfacial damage is delayed. As the embedded length of the shaped steel increases, the rate of interfacial damage slows down. The formula for predicting the bond strength between high-strength self-compacting concrete and steel was proposed, which effectively predicts the bond strength between these materials. Additionally, the bond stress-slip curve equations were established, showing good agreement with the experimental curves.