Mechanical Behavior of ECC and ECC/RC Composite Columns under Reversed Cyclic Loading

摘要

Engineered cementitious composite (ECC) is an advanced composite material with strain-hardening and multiple-cracking behaviors. The substitution of conventional concrete with ECC can significantly improve the deformation and energy dissipation ability of reinforced concrete (RC) columns. This paper reports on the mechanical behavior of ECC/RC composite columns. An ECC/RC composite column can be obtained by substituting concrete with ECC in the column bottom. The material composition, transverse reinforcement ratio, and axial load level were considered as experimental parameters. Experimental results from reversed cyclic load tests on nine scaled columns are presented. The results indicate that ECC and ECC/RC composite columns have better ductility, better energy dissipation capacity, and slower stiffness degradation than RC columns. The increase in axial load on the ECC/RC composite column negatively affects the ductility but can considerably improve the load capacity and maintain the structural integrity. The results also indicate that the number of stirrups can be properly reduced in ECC and ECC/RC composite columns because of the high-shear strength of ECC.