Shear behavior of headed stud connectors in steel-MPC based high strength concrete composite beams

In this paper, magnesium phosphate cement (MPC) based high strength concrete (HSC) was first introduced into steel-concrete composite beams due to its better durability, good antirust performance, high early strength and eco-friendly. Twenty-four push-out specimens were conducted to examine the static behavior of headed stud connector in steel-MPC based HSC composite beams, including 21 MPC based concrete specimens and 3 normal concrete specimens. The failure modes, load-slip behavior, ductility, shear stiffness and shear capacity of stud connector were investigated. The effect of stud height, stud diameter, concrete strength and concrete type were also discussed. The test results showed that the shear behavior was greatly improved with the increase of the stud diameter. The aspect ratio, concrete strength and type had minor effect on the shear capacity of stud embedded in MPC based HSC concrete, while the shear stiffness and ductility were obviously affected. Furthermore, according to the existing equations and current design codes, the test results and calculated results of shear stiffness, load-slip behavior and shear capacity were compared and analyzed. Finally, an empirical equation considering stud diameter was put forward to assess the load-slip relationship of headed stud embedded in MPC based HSC.