建設材料 炭素繊維シート補強部材の耐荷特性に与える鉄筋腐食の影響

Abstract

Strengthening technique using CFRP sheet has recently spread widely and strengthening of the existing RC structures deteriorated due to reinforcing steel corrosion is becoming important. Furthermore, it is also important to understand load carrying performance of strengthened RC member during its whole life under corrosive environment. In this study, corrosion of reinforcing steel in RC beams strengthened with CFRP sheet was simulated by the electrolytic corrosion using an external current source. Tension test of corroded reinforcing steel, observation of cracks due to reinforcing steel corrosion in cross section and static flexural test were carried out in order to investigate the influences of reinforcing steel corrosion on load carrying behavior of RC member strengthened with CFRP sheet. Additionally, finite element analysis was carried out using discrete joint elements for the bond between concrete and reinforcing steel, the bond between concrete and CFRP sheet and longitudinal crack due to reinforcing steel corrosion. Reinforcing steel corrosion hardly affected static load carrying behavior of RC member strengthened with CFRP sheet until yield. However, longitudinal distribution of strain in CFRP sheet was changed to be uniform by longitudinal crack due to reinforcing steel corrosion, which was successfully simulated by the finite element analysis.