JPH0743461U - Coated anticorrosion structure for steel structures - Google Patents

Abstract

(57) [Summary] [Purpose] The present invention relates to a corrosion preventive structure for a steel structure in which the top of a basic steel material constructed in the soil of a river, a harbor, etc., underwater, or above the water surface is embedded in reinforced concrete. [Structure] The exposed portion of the basic steel material 2 above the low water level is covered with an anticorrosion coating material 5 composed of an anticorrosion material 3 and a protective cover 4 on the outside thereof, and the upper end portion of the anticorrosion coating material 5 and the lower surface of the reinforced concrete 1 are covered. A coated and anticorrosive structure for a steel structure in which a wax layer 6 is formed on at least a boundary portion between and with a lower surface of the reinforced concrete 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an anticorrosion structure for a steel structure in which the top of a basic steel material constructed in the soil of a river, a harbor, etc., underwater, or above the water surface is buried in reinforced concrete.

[0002]

[Prior art]

 The tidal zone of the basic steel material such as steel pipe piles in a steel structure such as a pier is corroded severely due to repeated contact of sea water and river water and contact of oxygen in the air. Has undergone anticorrosion treatment.

Conventionally, as the anticorrosion treatment of this kind of steel structure, an anticorrosion material such as petrolatum-based anticorrosion tape is wound around the surface of the basic steel material, and the outside thereof is covered with a protective cover such as fiber reinforced plastic (FRP) or polyethylene. The anticorrosion coating structure and the anticorrosion coating method of applying underwater curing type epoxy resin putty to the surface of the basic steel are widely used. These methods prevent the corrosion of the basic steel material by forming an insulating oxide film on the surface of the basic steel material or physically forming an insulating layer to block corrosion factors such as seawater.

However, when this type of anticorrosion coating method is applied to a basic steel material of a steel structure, a gap is created at the boundary between the upper end of the anticorrosion coating material or anticorrosive paint of the basic steel and the lower surface of the reinforced concrete, and Corrosion of the basic steel in this part progresses because seawater and its splashes penetrate. Conventionally, in order to solve such a problem, a synthetic resin such as putty is filled at the boundary between the upper end of the basic steel material or the upper surface of the anticorrosive paint and the lower surface of the reinforced concrete, and the anticorrosive coating material or the anticorrosive paint of the basic steel material is filled. It closes the gap created at the boundary between the upper end and the bottom surface of the reinforcing steel concrete.

[0005]

[Problems to be Solved by the Invention] However, the synthetic resin such as the putty has excellent adhesiveness to the basic steel material but has poor sealing property to the reinforced concrete surface, so that the synthetic resin of the putty etc. filled in the boundary portion is deteriorated. A gap is created between the resin and the bottom surface of reinforced concrete, and this boundary cannot be completely sealed.Since waves and droplets of salt penetrate through this gap, it is not possible to achieve sufficient corrosion protection of the basic steel material inside. was there. In addition, the waves and splashed salt penetrated from the bottom surface of the reinforced concrete for a long period of time also corrodes the reinforcing steel in the concrete of the steel structure, causing rust to flow out onto the concrete surface, and in extreme cases, the bottom surface of the concrete will peel off. Sometimes it is a problem.

[0006]

[Means for Solving the Problems]

 Therefore, as a result of research to solve such conventional problems, the present inventor has found that the top of a basic steel material constructed in soil, water, and the surface of the water is the foundation of a steel structure that is embedded in a rebar concrete. Almost above the low water level of the steel material is covered with an anticorrosion coating material consisting of an anticorrosion material and a protective cover on the outside or coated with an anticorrosion paint, and the upper end portion of the anticorrosion coating material or anticorrosion paint and the lower surface of the reinforced concrete are If at least the boundary and the surface of the reinforced concrete are filled with wax, the gap between the upper end of the anticorrosion coating material or anticorrosion paint and the lower surface of the reinforced concrete can be completely eliminated, and the basic steel material in that portion can be completely removed. In addition, the reinforcing bars in concrete can be completely shielded from corrosive environments such as seawater and splashes. Penetrates into the cleat, therefore, Hirakiki hole in the concrete is filled with wax completely blocked salinity intrusion is to obtain a finding that it is possible to achieving a corrosion over time.

[0007] The present invention has been made based on such knowledge, and the top of a basic steel material constructed in soil, water and above the water surface is buried in reinforced concrete, and the low tide of the basic steel material of the basic steel material is almost the same. The exposed part above the water level is covered with an anticorrosion coating material consisting of an anticorrosion material and an outer protective cover or coated with anticorrosion paint, and at least the boundary between the upper end of the anticorrosion coating material or anticorrosion paint and the lower surface of the reinforced concrete. The present invention is characterized by a coated anticorrosion structure of a steel structure in which a wax layer is formed on the lower part and the lower surface of the reinforced concrete, and a synthetic anticorrosion structure of a steel structure in which the surface of the wax layer is further coated with a synthetic resin paint.

[0008]

[Action]

 The operation and structure of the coated anticorrosion structure for a steel structure according to the present invention will be described more specifically with reference to the drawings. FIG. 1 is a cross-sectional view of a coated anticorrosion structure for a steel structure according to the present invention, in which the top of a basic steel material 2 of a steel structure constructed in soil, water, or above the water surface is embedded in a reinforcing bar concrete 1. A portion of the basic steel material 2 exposed in the air and water is covered with an anticorrosion coating material 5 composed of an anticorrosion material 3 and a protective cover 4 on the outside thereof.

Before applying wax, foreign matter such as marine organisms adhering to the surface of reinforced concrete is removed, and if the surface of reinforced concrete is wet, the adhesion of wax deteriorates. To remove water by heating with a burner or the like so that it is preferably 5% or less

A wax layer is applied by brushing or spraying a heated wax to the upper end of the anticorrosion coating 5, the lower surface of the reinforced concrete 1 and the boundary between the upper end of the anticorrosion coating and the reinforced concrete 1. 6 is formed.

The wax layer 6 is preferably formed by using a microcitarine wax or a mixed wax of paraffin wax and microcitarine wax. This is because microcrystalline wax is more viscous than paraffin wax, has a strong impact at room temperature, and is difficult to peel off.

Further, the wax layer 6 brushed or sprayed on the reinforced concrete is infiltrated into the fine pores on the concrete surface when heated with a kerosene burner or the like. By forming the wax layer 6 on the entire lower surface of the reinforced concrete 1, salt penetration from the lower surface of the reinforced concrete 1 can be prevented, and corrosion of the entire reinforcing bar inside the reinforced concrete 1 can be prevented.

In this way, since the boundary between the upper end of the anticorrosion coating material 5 and the reinforced concrete 1 and the surface of the reinforced concrete 1 are completely covered with the wax having excellent waterproofness, the foundation inside the boundary is The insides of the steel material 2 and the reinforced concrete 1 can be completely shielded from the corrosive environment such as seawater and its splashes, and therefore, the corrosion of the basic steel material 2 and the reinforcement can be prevented for a long period of time.

Further, even when the wax layer 6 is deteriorated, maintenance and repair can be easily performed by the above-described method, and after the surface of the wax layer 6 is roughened, the synthetic resin paint 7 such as epoxy resin is applied to the wax layer 6. If it is applied to the surface of No. 6, the performance as a waterproof film is strengthened and the deterioration of the wax layer 6 due to ultraviolet rays is prevented, so that the boundary between the upper end of the anticorrosion coating material 5 and the reinforced concrete 1 is maintained for a longer period of time. It is possible to prevent corrosion of the basic steel material 2 inside the part and the reinforcing bars in the concrete.

It should be noted that, in the exposed portion of the base steel material 2 in water and above the water surface, instead of the anticorrosion coating material 5 consisting of the anticorrosion material 3 and the protective cover 4 on the outside thereof, an anticorrosion material such as an underwater curing type epoxy putty as shown in FIG. The paint 8 may be applied.

[0016]

【Example】

 A tape-like non-woven cloth impregnated with petrolatum-based rust preventive was used as an anticorrosive material between the bottom of the reinforcing steel concrete and the bottom of the water level of the two steel pipe piles about 0.5 m below the low tide of the new pier. A protective material made of fiber reinforced plastic (FRP) was covered as a protective cover to form an anticorrosion coating material, and the protective cover was fixed to the steel pipe pile by tightening the protective cover with bolts and nuts.

In addition, after the lower surface of the reinforced concrete was sanded with a sander, the water content of the concrete surface was measured by a surface moisture meter, and as a result, it was 3 to 10%. Therefore, the concrete surface was roasted to 5% or less with a kerosene burner.

Next, a mild steel test piece having a length of 150 mm, a width of 50 mm, and a thickness of 1.6 mm is placed on a concentric circle having a radius of about 1 m from the center of the steel pipe pile on the lower surface of the reinforced concrete around each steel pipe pile. Four pieces were arranged and fixed with concrete anchor bolts.

After that, paraffin wax and microclitaline wax are mixed and melted at a ratio of 50:50, and one of the above steel pipe piles has a width of a radius of about 2 m from the upper end of the anticorrosion coating material of the steel pipe pile and the center of the steel pipe pile. After brushing the wax on the lower surface of the reinforced concrete in the range, it was roasted with a kerosene burner to a wax film thickness of 300 to 600 μm.

Further, after roughening the boundary between the upper end of the anticorrosion coating material and the lower surface of the reinforced concrete and the wax surface having a radius of about 75 cm from the center of the steel pipe pile with a wire brush, the epoxy resin coating is applied to a thickness of about 200 μm. It was applied and left in this state for 1 year.

Only the epoxy resin putty is filled in the boundary between the upper end of the anticorrosion coating material of the other steel pipe pile and the lower surface of the reinforced concrete, and no wax is applied to the surface of the epoxy resin putty and the lower surface of the reinforcing steel concrete around it. I left it for one year.

As a result of observing the corrosion state of the steel pipe pile and the test piece after being left for one year, rust juice flowed out from the boundary between the reinforced concrete lower surface of the steel pipe pile not coated with wax and the epoxy resin putty, and the test piece All four sheets were covered with a reddish-brown thin rust layer, but no rust juice was found at the boundary between the bottom surface of the reinforced concrete of the steel pipe pile coated with wax and the anticorrosion coating agent. There was no rust at all. Moreover, no peeling point was observed in the wax surface or the epoxy resin coating applied to the wax surface.

[0023]

EFFECTS OF THE INVENTION As described above, the steel structure anti-corrosion structure of the present invention is as follows: (1) The exposed portion of the basic steel material of the steel structure above the low water level is almost entirely covered with the food material and the outer protective cover. Corrosion is prevented by the anticorrosion coating material or anticorrosion coating consisting of, and the boundary between the top edge of the coating material or anticorrosion coating and the bottom surface of the reinforced concrete is sealed with a wax layer, so that good corrosion protection is achieved over the entire corrosion protection range of the basic steel material. (2) By covering the reinforced concrete surface of the steel structure with a wax layer, the reinforcing bars in the concrete can be completely shielded from the corrosive environment such as seawater and splashes. Since it infiltrates into the holes, it has good adhesion to concrete and does not easily peel off due to the collision of waves or suspended matter, and it is extremely easy to repair it for a long time. Corrosion protection of reinforcing bars in concrete can be achieved over time. (3) By applying synthetic resin paint to the wax layer surface, the performance as a waterproof film is enhanced and the weather resistance of the wax is improved. Furthermore, it has the excellent effect of being able to prevent the corrosion of the steel material inside the boundary between the coating material or the anticorrosion coating of the basic steel material and the reinforced concrete and the reinforcing steel without concrete over a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a coated anticorrosion structure for a steel structure according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the steel structure anticorrosion structure of the present invention.

[Explanation of symbols]

 1 Reinforced concrete 2 Basic steel 3 Anti-corrosion material 4 Protective cover 5 Anti-corrosion coating material 6 Wax layer 7 Synthetic resin paint 8 Anti-corrosion paint

Claims (2)

[Scope of utility model registration request] 1. In a steel structure constructed by burying reinforced concrete at the top of a basic steel material constructed in the soil, underwater and over the water surface, the exposed portion of the basic steel material above the low water level is used as a food protection material and Covering with an anticorrosion coating material consisting of an outer cover or coating with an anticorrosion coating, and forming a wax layer at least at the boundary between the upper end of the anticorrosion coating material or anticorrosion coating and the lower surface of the reinforced concrete and the lower surface of the reinforced concrete. A coated anticorrosion structure for steel structures. 2. The coated anticorrosion structure according to claim 1, wherein a synthetic resin paint is further applied onto the wax layer.