Experimental study on axial compression of hybrid fiber cement-based composite column with circular cross section

Abstract

In this study, hybrid fiber cement-based composite materials are used to make the confinement layer of the composite column, and plain concrete is poured inside to form the composite column. Considering the thickness of the confinement layer, the strength of the mixed fiber cement-based composite material of the confinement layer, and the strength of the inner core concrete, two sets of eighteen composite column specimens were designed and fabricated for axial compression tests to study the axial compression performance of the composite columns. The results showed that: The main factor that affects the occurrence time of cracks in composite columns is the strength of the cement-based composite material of the confinement layer. Through the analysis of the load–strain curve, it is found that the influence of the thickness of the confinement layer and the strength of the core concrete on the peak load of the composite column depends on the strength of the confinement layer: When the strength of the confinement layer is greater, the greater the thickness of the confinement layer and the smaller the strength level of the core concrete, the greater the peak load; when the strength of the confinement layer is smaller, the greater the thickness of the confinement layer and the smaller the strength level of the core concrete, the smaller the peak load. The peak strain is mainly related to the thickness of the constrained layer and the strength of the cement-based composite material of the confinement layer; When the strength of the confinement layer is smaller, the greater the thickness of the confinement layer and the smaller the strength of the core concrete, the better the ductility; when the strength of the confinement layer is greater, the specimen with the thickness of the confinement layer of 62.5 mm has better ductility; Based on statistical principles, the bearing capacity prediction formula and peak stress prediction formula of the composite column are established, and the calculated values are in good agreement with the experimental values.