Suppression of Fracture Failure at Steel/Concrete Interaction Zones by Material Ductility in ECC

Concrete fracture failure is often observed at interaction zones between steel and concrete, including those in hybrid structure connections, shear studs in composite beams, and steel fasteners in concrete. Improvement in intrinsic ductility of the concrete material should suppress such failure mode and enhance the overall structural performance. In this paper, we introduce and experimentally demonstrate the feasibility of this concept via two case studies, i.e., the shear behavior of steel stud/ECC connection and pullout behavior of 2D anchor bolt/ECC connection. The micromechanically designed ECC (Engineered Cementitious Composite) with a tensile ductility three hundred times that of normal concrete totally eliminated the brittle fracture mode by developing extensive “plastic” deformation in both ECC and the steel stud in the first case and in ECC in the second one. This modification in behavior led to higher load capacity and ductility, thus enhancing structural response. The enhancement in structural response through material ductility engineering is expected to be applicable to a wide range of engineering structures where steel and concrete comes into contact.