Study On Corrosion Resistance Of 6061-T6 Aluminum Alloy And Its Application In Reinforced Concrete Structure

Reinforced concrete structure is widely used in building structures of many types,But in the coastal areas and chemical plants and other harsh environment, concrete reinforcement will be corroded, and the corrosion of steel is easy to reduce the durability of the structure. To solve the problem of corrosion of steel bars,good corrosion resistance of 6061-T6 aluminum alloy used in concrete structures were studied in this paper. Aluminum Alloy has the advantages of light weight, high strength, good ductility, characteristics of corrosion resistance and excellent mechanical properties, which is widely used in military, civilian, in building structure for large space truss structures, but there are few applications in concrete structures. The purpose of this study is to explore the application of aluminum alloy bars in the concrete structure, and be the basis of further study for the wide application prospect of aluminum alloy reinforced concrete in civil engineering. The major contributions of the work presented in this thesis are listed as follows:1. Through the test of the quality method research the corrosion rate of 6061-T6 aluminum alloy in chloride solution, simulated acid rain solution and Saturated limestone aqueous solution, respectively, and evaluate the corrosion resistance of 6061-T6 aluminum alloy based on metal corrosion resistance classification standard. Test results indicated that the corrosion rates of 6061-T6 aluminum alloy in chloride solution and simulated acid rain solution were 0.037mm/a and 0.051mm/a, respectively, but the corrosion rate in saturated lime water solution was as high as 16.166mm/a, which shows that 6061-T6 aluminum alloy has good corrosion resistance in chloride solution and simulated acid rain solution, but the corrosion resistance of the alloy is very poor in saturated lime water solution.2. In order to reveal the basic law of corrosion and the corrosion mechanism of 6061-T6 aluminum alloy in different solution, this paper carried out the electrochemical experiments. By comparing the polarization curves and electrochemical impedance spectroscopy of 6061-T6 aluminum alloy and steel bar, analysis of the corrosion mechanism of 6061-T6 aluminum alloy in different solution, and analysis of steel and 6061-T6 aluminum alloy corrosion in different solutions. The analysis shows that the corrosion resistance of 6061-T6 aluminum alloy is better than that of steel bars in the chloride solution and simulated acid rain solution, and the corrosion resistance of 6061-T6 aluminum alloy is worse than that of the steel bar in saturated lime water solution.3. Based on the fact that corrosion resistant performance of 6061-T6 aluminum alloy is better than that of rebar, and to confirm that the feasibility of aluminum alloy can be applied in concrete instead of steel bar, this paper studied the bonding properties of aluminum alloy bar and concrete through fourteen groups central pullout tests, which include six groups pullout specimens with plain aluminum alloy bars, six groups pullout specimens with plain steel bars and two groups pullout specimens with deformed steel bars, analyzing the difference of bonding mechanism of the three pullout specimens and studying the damage feature of round steel bar specimens. The failure characteristics of the center of the round steel bar are studied, and the composition of the bond stress between the aluminum alloy bar and the concrete is given. The result indicates that the bonding strength of aluminum alloy is composed of only glue focus with size of 0.21 ~ 0.56 MPa that about 1/10 bond strength of the round bar.4. Aluminum alloy steel used in reinforced concerte structures as reinforcing steel including two application methods of aluminum alloy steel external prestressed reinforcement and near surface strengthening muscle. This paper use ANSYS to research the loaded performance of concrete beam which is reinforced with external prestressing, analysis the basic performance of aluminum alloy bar for reinforced concrete members. Then, replacing the external prestressed tendons by high strength aluminum alloy bars with the principle of equal section and equalling strength, and analyzing the new models. Compared with the beam which is reinforced by the external prestressed high strength steel wire, the improvement of the ultimate bearing capacity of the beam which is reinforced by the aluminum with the same section area is less, but the use of aluminum alloy reinforcement can improve concrete reinforcement beam deformation performance and improve the ductility of the concrete beam. In the same strength of the aluminum alloy, the bearing capacity and the ductility of concrete beams can be improved correspondingly. Thought 6061- T6 aluminum alloy steel reinforced concrete beam surface strengthening experimental exploration of aluminium alloy steel as the feasibility of reinforcing steel used in reinforced concrete structure. The research shows that the bearing capacity of the reinforced concrete beam increased by 18%, and the ductility of reinforced concrete beam after reinforcement is significantly improve, which make full use of the corrosion resistance and good ductility of 6061-T6 aluminum alloy.