Study On Anti-Corrosion Of The Pre-strengthened Column With CFRP

Reinforced concrete structures which in the marine environment, are being deteriorated due to the long-term effects of corrosion and external load. The capacity and durability of the structures are significantly declined and the life of the structures are also decreased. To obtain an excellent way with anti-corrosion and strengthened effect for reinforced concrete structures has become the focus of civil engineering. In recent years,the fiber reinforced polymer has been widely used for repairing concrete structures suffer from corrosion damage. However, the double effect of strengthen and corrosion protection with FRP needs further studying. Focus on the bridge pier in offshore environment, the deterioration of mechanical properties of the un-reinforced columns and pre-reinforcement columns was studied, the Anti-corrosion of CFRP material was evaluated under the marine environment, and the fatigue properties of the CFRP pre-reinforcement concrete columns with corrosion damage was studied. The main contents are as follows:(1) A total of 36 plain concrete were prepared for mechanical test.24 cylinders were strengthened using two different schemes of CFRP wraps(full wrapped and strip wrapped). All specimens were placed in artificial seawater for different corrosion time. The relationship between corrosion damage degree and the mechanical properties was studied. The test results show that:CFRP material not only improved the compression performance of the specimens but resisted corrosion as well. The deterioration of the pre-strengthened specimens was significantly lower than the un-strengthened specimens. Pre-strengthened scheme of CFRP wraps had an important influence on the anti-corrosion effect.(2) 11 reinforced concrete columns with square section and 5 columns with circle section were prepared.8 reinforced concrete columns were wrapped with single layer of CFRP sheets before the corrosion initiation. The corrosion was induced by means of an impressed direct current. The properties of the specimens were studied through the different wrapping schemes and corrosion degrees under the axial pressure and cycle bending loads supplied by the material test system (MTS). Results showed that the application of CFRP sheets was efficient in protecting reinforced concrete (RC) columns from corrosion. It was found that the corrosion degree related to the scheme of CFRP wraps, while the fatigue life and the ductility of specimens strongly connect with wrapping scheme and corrosion damage.Test results showed that CFRP pre-reinforcement technology could improve the mechanical properties while resist corrosion of the component.It was provided some basis for application of this technology in actual project.