Compressive behavior of ultra-high-performance-normal strength concrete (UHPC-NSC) column with the longitudinal grooved contact surface

Abstract

This study presents the experimental investigation of the axial compressive behavior of the 23 circular base composite column specimens. The columns consist of core normal strength concrete (NSC) and outer surface ultra-high-performance concrete (UHPC). The parameters studied in the investigation are contact surface longitudinal groove thickness, hoop reinforcement spacing (volumetric ratio of shear reinforcement), and core NSC compressive strength. The influence of these parameters on the compressive behavior of the UHPC-NSC composite columns was reported and discussed. The test results indicated that increasing groove thickness and NSC compressive strength improved the compressive resistance of the composite columns. However, increasing the hoop reinforcement spacing shows no effect on the compressive resistance. An analytical model was proposed based on the experimental data to predict the compressive stress-strain relation of the novel UHPC-NSC composite column. Finally, the behavior of the composite columns was simulated using a 3-dimensional finite element model (FEM). Validations against the provided test results demonstrated that the FEM accurately predicted the compressive behavior of the UHPC-NSC composite columns.