Mechanical behavior of uhpc having various binder compositions and influence of such infilled concrete on the structural response of cfst columns

To enhance the sustainability of a structure, three pillars of the sustainability, namely, environmental, social, and economical factors are needed to be considered in the design. On this issue, the development of new structural composite systems with high performance plays a critical role. This study contained two parts: Firstly, the experimental results on the mechanical behavior of ultra high performance concrete (UHPC) mixed with various binder types and volumes were given. Whereas, the second part provided the numerical results on the structural behavior of steel tube column infilled with such UHPC. For this, single, binary, ternary and quarternary binder systems up to 75% replacement levels were used to develop 26 different UHPC mixtures with low cement content. All designed mixtures were tested for identifying the properties of core concrete. Moreover, three diameter to wall thickness D/t ratios (35, 65, and 95) matched by 300, 450, and 600 MPa of yield strength (fy) of the steel tube were used to calculate and examine the axial load capacity of circular concrete filled steel tube (CFST) with UHPCs through design equations given by Eurocode 4 (EC4), American Concrete Institute (ACI) and Chinese (DL/T) codes. The results of experimental and numerical study were given and discussed accordingly.