STRENGTH PERFORMANCE OF EXPANSIVE CONCRETE FILLED CFST COLUMNS UNDER AXIAL LOADING

This study investigates the bond strength and axial compressive strength of concrete-filled circular steel tubes (CFST) columns using expansive concrete. Expansive concrete is a type of concrete that can generate internal expansive pressure, leading to improved bond strength and increased compressive strength. The study involves experimental testing of 16 CFST columns filled with expansive concrete and regular concrete as a control. The test results show that the bond strength of the expansive concrete-filled CFST columns is significantly higher than that of the regular concrete-filled columns. The increase in bond strength is attributed to the formation of micro-cracks in the expensive concrete, which enhance the mechanical interlocking between the steel tube and the concrete. The study also found that the axial compressive strength of the expansive concrete-filled columns is higher than that of the regular concrete-filled columns. This is due to the internal expensive pressure generated by the expansive concrete, which leads to denser concrete and higher compressive strength. Additionally, the effect of confinement on the bond strength and axial compressive strength of the columns was also investigated. The results showed that the confinement provided by steel hoops significantly improves both the bond strength and axial compressive strength of the expansive concrete-filled columns