摘要详情
115 / 2022-04-26 11:36:03
Protection against deterioration of reinforced bar in concrete with phosphate cement based composite coating
steel bar; MPC coating; PVA fiber modified; X-Ray computed tomography, corrosion protection
全文待审
Magnesium phosphate cement (MPC) is a type of chemically bonded phosphate ceramic that is widely used in engineering, such as concrete structure repair, heavy metal solidification, nuclear waste encapsulation, and thermal insulation. It can develop high early strength at ambient temperature. The hardened MPC paste has a low permeability, low shrinkage, and excellent adhesion with many substrates. If it is used as a coating, it will form an excellent barrier that has the potential passivation ability to steel bar. This study aims to test the performance of MPC-based reinforcement protection coating. By adjusting the workability of the fresh mixed MPC slurry, a ceramic coating was formed on the surface of the rebar, then the mechanical properties and the bonding strength between steel and concrete were tested by a pull-out test. And the corrosion protection effect of the MPC coating was evaluated by polarization experiments.
The following results were obtained from the current research on various properties of MPC-based coatings. The MPC-based rebar coating has a good performance in mechanical properties. It has little effect on the bond properties of reinforcing steel and concrete, especially with PVA fiber-modified MPC coatings. This effectively overcomes the epoxy coating problem in this area. At the same time, it can be effectively stretched along with reinforcing bars and defects occur only after the bars have entered the yield phase, Fig. 1 and Fig. 2. At the same time, the adhesion of coating and steel is also excellent, and it can be well integrated with reinforcing steel. These properties ensure that the coating is intact and effective to protect the steel under the design loads in the coagulation structure.
The MPC-based rebar coating has an excellent performance in terms of durability. It can effectively protect the steel from corrosion in environments containing chloride ions. The rebar has a very low corrosion current under the protection of the coating and can be subject to passivation, Fig. 3 and Fig. 4. The coating has a strong resistance to highly alkaline environments, which is conducive to its good work in concrete. From the observation of the inner surface of the coating, it was found that the P element contained in the coating reacted with the steel containing the Fe element to form a passivation film. This is one of the reasons why the MPC coating can effectively protect the steel bar.
X-Ray computed tomography (XCT) non-destructive test showed that the coating based on MPC can protect steel bar and reduce its corrosion rate in the long-term corrosion process. In terms of mechanical properties and durability, PVA fiber-modified MPC coatings perform better than MPC coatings. This indicates that PVA fiber can effectively enhance the toughness of the coating, reduce internal defects, and provide better performance.
The following results were obtained from the current research on various properties of MPC-based coatings. The MPC-based rebar coating has a good performance in mechanical properties. It has little effect on the bond properties of reinforcing steel and concrete, especially with PVA fiber-modified MPC coatings. This effectively overcomes the epoxy coating problem in this area. At the same time, it can be effectively stretched along with reinforcing bars and defects occur only after the bars have entered the yield phase, Fig. 1 and Fig. 2. At the same time, the adhesion of coating and steel is also excellent, and it can be well integrated with reinforcing steel. These properties ensure that the coating is intact and effective to protect the steel under the design loads in the coagulation structure.
The MPC-based rebar coating has an excellent performance in terms of durability. It can effectively protect the steel from corrosion in environments containing chloride ions. The rebar has a very low corrosion current under the protection of the coating and can be subject to passivation, Fig. 3 and Fig. 4. The coating has a strong resistance to highly alkaline environments, which is conducive to its good work in concrete. From the observation of the inner surface of the coating, it was found that the P element contained in the coating reacted with the steel containing the Fe element to form a passivation film. This is one of the reasons why the MPC coating can effectively protect the steel bar.
X-Ray computed tomography (XCT) non-destructive test showed that the coating based on MPC can protect steel bar and reduce its corrosion rate in the long-term corrosion process. In terms of mechanical properties and durability, PVA fiber-modified MPC coatings perform better than MPC coatings. This indicates that PVA fiber can effectively enhance the toughness of the coating, reduce internal defects, and provide better performance.
重要日期
-
会议日期
03月11日
2023
至03月13日
2023
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02月17日 2023
初稿截稿日期
-
02月17日 2023
提前注册日期
-
03月13日 2023
注册截止日期
主办单位
深圳大学
香港理工大学
香港理工大学
