Evaluating Adhesive Quality at the Interface Between Rebar and Concrete Using the Nondestructive Test Methods and Investigating the Bond Behavior under the Adhesion Damage

• Main Authors: Lin, Yu-Feng, 林喻峰
• Other Authors: Yiching Lin
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/69877828796144042281

博士 === 國立中興大學 === 土木工程學系 === 91 === This thesis investigates the feasibility of using the nondestructive test and the bond strength test methods for evaluation of the bond quality at the interface between reinforcing bars and concrete. The adhesive condition at the rebar/concrete interface might be damaged during construction due to some unexpected factors such as the unclean surface of rebars or a severe disturbance shortly after concrete placement. In the laboratory studies, the simulation of the abnormal interface between rebars and concrete includes smearing epoxy and oil on the surface of rebars and vibrating the beam specimens shortly after concrete placement. The abnormal rebar/concrete interface reduces the adhesive strength and the vibrated beams possibly exists cracks. The impact-echo and small-diameter break-off techniques are adopted to evaluate the adhesive damage at the rebar/concrete interface. In addition, the loading tests are also carried out to study how the interfacial adhesion affects the bond behavior of the specimens. Nondestructive test results show that there exists a significant difference in the impact-echo responses between the normal and abnormal rebar/concrete interfaces. The small-diameter break-off test can give information about the degree of adhesive damage at the rebar/concrete interface. The results obtained from the loading tests show that the adhesion damage results in a lower load carrying capacity to have an initial crack and a reduction in the ultimate bond stress of the beam specimens up to 20%. It is also shown that a ductile failure occurs when the rebars are sufficiently confined by stirrups.