Structural Performance of Self-Consolidating Concrete Used in Confined Concrete Columns

摘要

This paper compares the mechanical performance of highly confined columns cast with normal concrete (NC) vibrated into place to ensure proper filling and consolidation equivalent to that of identical columns cast with self-consolidating concrete (SCC). The tested columns had nominal concrete compressive strengths of 40 to 80 MPa. Two confining stirrup configurations representing different degrees of confinement were used. The confining stirrups had nominal steel yield strengths of 400 to 800 MPa. A total of 16 columns were tested in this experimental investigation: 11 were cast either with NC or SCC in reinforced sections; five accompanying columns were cast without reinforcement. Three of the unreinforced columns were tested in uniaxial compression to determine the overall concrete compressive strength of the large-scale columns, while two others were cored to determine the distribution of the in-place compressive strength and modulus of elasticity along the column height. The test results on reinforced columns showed that SCC yielded greater ductility, although it developed slightly lower ultimate compressive strength than NC. The study also confirmed that an increase in the stirrup yield strength can generate a high degree of confinement in well-confined concrete columns provided that stirrup spacing is kept small. The coring of unreinforced concrete columns demonstrated that the distribution of in-place properties over the column height is more homogeneous in the case of SCC than NC, which was also found to be generally adequate.