Evaluation of the modified Near Surface Mounted (NSM) CFRP Reinforcements for the Strengthening of the Concrete Structures
Loss of composite action due to debonding of the carbon fiber reinforced polymer (CFRP) from the concrete structure is one of the main concerns that underutilize the high-strength CFRP materials.Several papers claim that the near-surface mounted (NSM) system performs relatively well compared to the external bonding (EB) systems by delaying the debonding of the CFRPs from the concrete.However, till now, mitigating such debonding failure mode is still considered as one of the major challenges hindering the higher utilization of the CFRP materials in the strengthening design.This paper presents the comparison of the effectiveness of the CFRP reinforcement used as a NSM system and the EB system.The results are presented in two parts.Initially, investigation on the bond properties of the CFRP reinforcements and concrete composite of altogether 11 cases (3 EB and 8 NSM) were evaluated by the single-lap shear bond test.Generally, CFRP plates (strips) or rods are used for a NSM FRP system due to wide availability and ease in construction, but in this study, apart from the CFRP plate, non-conventional forms of the reinforcements, such as carbon fiber sheet (CFS) and carbon fiber strand sheet (CFSS) were chosen with the purpose of enhancing the adhesion property and reduce the material cost of the system.In addition, several filling materials such as adhesive, resin-mortar, high-strength cement grout and polymer-cement mortar were examined to determine the most cost-effective solution as the groove filling material for the NSM system.Despite having the similar axial stiffness, the bond action in the non-conventional NSM systems performed well leading up to the rupture of the carbon fiber reinforcements, while other systems suffered premature debonding with the CFRP utilization in the range between 16% to 60%.Based on the results of the bond test, 4 NSM systems that could achieve the rupture of the CFRPs were used for the flexural strengthening of the beam members.The results showed up to 33% and 55% higher ultimate failure load respectively compared to the conventional NSM CFRP system and the EB CFRP system.In addition, the CFRP utilization for the 3 NSM systems exceeded the rupture strain indicating that full-composite action was achieved till the ultimate failure of the beams.
Near Surface Mounted (NSM)、carbon fiber sheet (CFS) carbon fiber strand sheet (CFSS) bond concrete
J.Shrestha M.Seki A.Komori
Takenaka Civil Engineering & Construction Co., Ltd., Tokyo, Japan Nippon Steel Chemical & Material Co., Ltd. Tokyo, Japan
国际会议
福州
英文
1145-1154
2018-11-04（万方平台首次上网日期，不代表论文的发表时间）