Effect of CFRP on Behavior of Confined Lightweight Concrete Square Specimens

摘要

In concrete construction, self-weight represents a very large proportion of the total load on the structure. Lightweight concrete (LWC) have many advantage such as less dead load consequently smaller cross section and better durability. The design guidelines recognize an increased concrete strength due to confinement and provide design equations for rectangular columns wrapped with Carbon fiber reinforced polymers (CFRP). An effect of CFRP on behavior of confined lightweight concrete element is one of the areas needed to research. It is well known that confinement of concrete is effective in increasing its strength and deformation capacity. It is generally agreed that the strength and stiffness of confined material as well as the compressive strength of the unconfined concrete. The behavior of confined and unconfined concrete specimens under uniaxial loading was studied. A numbers of tests were carried out on 150×150×300 mm (5.9×5.9×11.81 in) square specimens. In order to prevent the fiber from being folded and to decrease the concentration of stress, the section corners were chamfered to a radius of 5 till 25 mm (0.196 till 0.984 in). Two type of CFRP, fully wrap and strap was used for confining of lightweight concrete specimens. The axial and lateral strain versus of specimens was compared. That these curves have shown is increase of ultimate strength and strain, specimen stiffness in effect of confinement and increase of corner radius.