Proper

Abstract

The Concrete-Filled in Tube(CFT) system has been developed to behave well in structural performance such as stiffness, stress, ductility that is derived from its mechanical advantages of composite structure. However, since the exterior is piled up by steel pipes, the concreted surplus bleeding water is concentrated in the upper part. Therefore, there is a disadvantage that the upper joint portion of the column, which is a main structure, may be weakened. Therefore, there is a need for a system for eliminating bleeding except for the number of compounds required for the hydration reaction of the concrete. As a detailed system solution, the paper-drain was attached to the inner side of the CFT. Also, it is possible to increase the durability of the concrete by drilling holes in the upper, middle, and lower parts to remove excess water immediately after casting the concrete. Test results show the dense microstructure of concrete and the benefit of a paper-drain being able to let the redundant water out through some points of holes outside the concrete-filled in tube.