JP2997481B2 - Rust prevention coating method for reinforcing steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for anticorrosion coating of reinforcing steel, and can be used for anticorrosion coating of reinforcing steel of reinforced concrete.

(Background technology)

Generally, cellular concrete and the like that have been cured in an autoclave are neutralized immediately after production. Moreover, concrete is carbonated by carbon dioxide gas in the air, and the rust prevention effect is reduced. This carbonation makes the reinforcing bars inside the concrete more likely to corrode, so rust-proof coating is applied to the reinforcing bars to prevent rusting of the reinforcing bars over time.

Conventionally, this rust-preventive coating consists of a step of applying a rust-preventive material such as a mortar or a resin to a reinforcing bar, and a step of drying a coating film formed by the rust-preventive agent.
A rust-preventive coating film of a predetermined thickness is formed. The concrete slurry is solidified into a predetermined shape with the reinforcing bar having the rust-preventive coating film as a core. This concrete slurry is cured in an autoclave. In this way, cellular concrete reinforced with rebar is produced.

[Problems to be solved by the invention]

However, when using a mortar-based rust inhibitor, it is necessary to repeat the above two steps two or three times, and,
Since the drying process takes time, there is a problem that the efficiency of the painting operation is low. In addition, when a resin-based rust preventive is used, the drying process is performed by baking and drying, which shortens the time of the drying process. It is difficult to reduce the adhesion between the reinforcing steel and concrete. For this reason, there was a problem that the reinforcing effect was reduced.

An object of the present invention is to provide a method for rust-proofing a reinforcing bar that increases the reinforcing effect of the reinforcing bar and improves the working efficiency.

[Means and actions for solving the problem]

In the present invention, after cleaning the reinforcing bar, the reinforcing bar is pre-heated to a temperature at which the powder of the synthetic resin to be attached to the reinforcing bar does not melt, and the powder is primarily adhered to the reinforcing bar by using heat from the preheating. Before the powder is melt-hardened, the reinforcing steel to which the powder has been attached by primary attachment is wrapped with concrete slurry, and the concrete slurry is solidified into a predetermined shape. This is a method for rust-proofing a reinforcing bar in which a solidified concrete slurry is cured in an autoclave and the powder is secondarily adhered to both a reinforcing bar and concrete to form a rust-proof coating film.

At this time, it is preferable that the primary attachment of the powder to the reinforcing bar is performed by applying a charge to the reinforcing bar and applying a charge having the opposite polarity to the charge to the powder, that is, so-called electrostatic coating. .

As the powder, it is desirable to employ a thermosetting synthetic resin powder that is cured in a heated state.

By performing the rust-preventive coating of the reinforcing bar in this manner, when the reinforcing bar is wrapped in the concrete slurry, the powder can be prevented from falling off the reinforcing bar, and the powder film having a predetermined thickness is formed between the reinforcing bar and the concrete slurry. Formed. Moreover, the powder is strongly and secondarily attached to both the reinforcing steel and the concrete. Furthermore, since the coating is cured by utilizing the heat of the autoclave to form a rust-preventive coating film, the conventional drying step can be omitted.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4.

1 to 4 show a first embodiment of the present invention.

FIG. 1 shows manufacturing steps (A) to (K) of a lightweight cellular concrete panel according to the present embodiment, and a reinforcing bar according to the present embodiment includes steps (B) and (B) of the above manufacturing steps.
(C) and (J) are to be rust-proof painted.

As reinforcing steel to be rust-proof painted, reinforcing steel 10 shown in (A)
Is used. The reinforcing bar 10 has a rectangular frame 11 formed of a pair of long and short angle members and the like, and mesh bars 12 are formed on both upper and lower sides of the frame 11.

As shown in (B), the reinforcing bar 10 is heated by a heating device 15 such as an electric furnace at a temperature at which powder made of synthetic resin to be attached to the reinforcing bar 10 is not completely melted, for example, 115 to 1.
Preheated to 35 ° C.

As shown in (C), the reinforcing bar 10 is provided in a tank 17 containing a powder 16 made of a thermosetting synthetic resin, for example, an epoxy resin or the like, which is cured in a heated state before the heat of preheating is cooled. Placed in front of the nozzle 18 connected to the rebar
Powder 16 is sprayed on the whole 10. The powder 16 is primarily attached to the surface of the reinforcing bar 10 using the heat of the preliminary heating.

At this time, as shown in FIG.
A wire mesh 20 is arranged immediately before 19, and in this wire mesh 20, for example,
The positive electrode of a DC high-voltage power supply 21 having an output voltage of about 100,000 volts is connected. On the other hand, the negative electrode of the DC high-voltage power supply 21 is connected to the reinforcing bar 10. In this state, the powder 16 is ejected from the nozzle 18, and the powder 16 passes through the wire mesh 20 to give a positive charge to the powder 16. The powder 16 and the reinforcing bar 10 are given charges of opposite polarities to adhere the powder 16 to the surface of the reinforcing bar 10 with a uniform thickness, so-called electrostatic coating is performed.

As shown in FIG. 1 (D), the reinforcing bar 10 to which the powder 16 is adhered is put into a mold 25. This formwork 25 has a frame material around it.
22 are arranged in a rectangular shape, and the lower side of the rectangular shape is the third
As shown in the figure, the surface is covered with a bottom plate 24 covered with a release material 23 such as release paper. An irregular pattern is formed on the surface of the bottom plate 24. Further, at a predetermined height position from the bottom plate 24, the reinforcing bar 10 is supported by a support member (not shown).

As shown in FIG. 1 (E), a form 25 in which the reinforcing bar 10 is inserted is provided.
Is placed under the concrete slurry tank 26,
Inject concrete slurry 27E into 25. The surface of the poured concrete slurry 27E is leveled by means 28
Equalized by At this time, even if the concrete slurry 27E is injected into and out of the reinforcing bar 10, the powder 16 formed on the surface of the reinforcing bar 10 does not fall off due to the primary adhesion, as shown in FIG. The membrane 16L is maintained.

As shown in FIG. 1 (F), the concrete slurry 27E poured into the mold 25 becomes a solidified concrete slurry 27F after a predetermined time has elapsed.

As shown in (G), this concrete slurry 27F is taken out from the mold 25 together with the release material 23, and then the release material 23 is peeled off to form a semi-formed concrete 27G having a pattern formed on one side surface. Become.

The semi-formed concrete 27G is bundled with another semi-formed concrete 27G formed in the same manner, placed on one curing pallet 29, and carried into the sprinkler 30.

The concrete 27G in a semi-formed state is brought into the autoclave 31 after being bathed in the watering device 30 and pre-cured.

In the autoclave 31, the semi-compacted concrete 27G is cured at a high temperature and a high pressure, for example, at 180 ° C. in a saturated steam of 10 kg / cm ² for 4 to 16 hours to become a lightweight cellular concrete 27J. At this time, the powder 16 is melted using the heat of the autoclave curing, and the powder 16 is secondarily attached to the reinforcing bar 10 and the lightweight cellular concrete 27J. Further, the powder 16 that has been secondarily adhered is cured by using heat of the autoclave curing. After autoclaving, a rust-proof coating 16M is formed between the lightweight cellular concrete 27J and the steel frame 10, as shown in FIG.

Lightweight cellular concrete discharged from autoclave 31
27J is transported to painting and finishing processes, not shown, to complete the production of lightweight cellular concrete panels.

According to the above-described embodiment, the following effects can be obtained.

In other words, using the heat of autoclave curing, powder
16 is melted, powder 16 is reinforced 10 and lightweight cellular concrete
Since the powder is secondarily adhered to 27J and the secondly adhered powder 16 is cured to form a rust-preventive coating film 16M, there is no step that is performed repeatedly as in the conventional rust-preventive coating. Therefore, the efficiency of the rust-preventive painting operation can be greatly improved. Moreover, the secondary adhesion causes the anticorrosive coating 16M to adhere firmly to both the reinforcing bar 10 and the lightweight cellular concrete 27J, so that the lightweight cellular concrete 27J and the reinforcing bar 10 are integrated, and the reinforcing effect of the reinforcing bar 10 is increased. Can be improved.

Since the heat of the autoclave curing is used, there is no step corresponding to the conventional step of drying a rust-proof coating film. Therefore, the energy required for melting and curing the powder 16 can be reduced.

Since the powder 16 is primarily attached to the preheated reinforcing bar 10 by using the electric attraction and heat generated by the preheating, a film of the powder 16 having a predetermined thickness can be formed on the reinforcing bar 10. Moreover, when injecting the concrete slurry 27E into the formwork 25D,
The powder 16 does not fall off, and a coating film 16L having a predetermined thickness is obtained. Therefore, the rust-preventive coating film 16M is reliably formed. Therefore, it is possible to obtain a rust preventive paint film 16M having a high rust preventive effect.

In the electrostatic coating, the thickness of the powder 16 attached to the reinforcing bar 10 can be easily adjusted by increasing or decreasing the voltage between the wire mesh 20 and the reinforcing bar 10, so that the thickness of the anti-rust coating 16M is surely controlled. be able to.

FIG. 5 shows a second embodiment of the present invention. In the first embodiment, the preheating step and the primary deposition step are performed separately, but in the present embodiment, the preheating step and the primary deposition step are performed simultaneously.

That is, in this embodiment, the steps (B) and (C) of the manufacturing steps (A) to (K) of the lightweight cellular concrete panel shown in FIG. 1 are replaced with the steps shown in FIG. It is a thing.

In FIG. 5, the reinforcing bar 10 to which the powder 16 is to be primarily attached is suspended in the center of a closed room 32. This room
A blower 34 is installed on the floor 33 of the 32 with the outlet facing upward. Further, the room 32 is provided with a heating device 35 such as an electromagnetic heater for heating the reinforcing bar 10 by generating lines of magnetic force in the vertical direction inside.

A predetermined amount of the powder 16 is put in the room 32, and the blower 34 is driven to float the powder 16 in the room 32. In this state,
The heating means 35 is driven to preheat the rebar 10 to a temperature at which the powder 16 does not melt. The powder 16 floating in the room 32
When contacting the rebar 10, the heat of the preheating causes the rebar 10
Is primarily attached to At this time, since only the reinforcing bar 10 is heated, when the powder 16 adheres to the surface of the reinforcing bar 10 to a predetermined thickness, the heat of the reinforcing bar 10 is not conducted to the outside, and the powder 16 does not adhere more than necessary.

In this embodiment, the same operation and effect as those of the first embodiment can be obtained, and an effect of further reducing the rust-proof coating process can be added.

The present invention is not limited to the above-described embodiments, but includes the following modifications.

That is, the shape of the concrete is not limited to the panel shape, and may be, for example, a columnar shape or a cylindrical shape. In short, the shape is not limited. The shape of the reinforcing bar 10 may be determined according to the shape of the concrete.

The preheating is not limited to a heating device such as an electric furnace or an electromagnetic heater, and may be performed by, for example, passing a current directly to the reinforcing bar 10. In short, the preheating method and means are not limited as long as the rebar 10 can be heated to a temperature at which the powder 16 does not melt.

〔The invention's effect〕

As described above, according to the rust-proof coating method for a reinforcing bar of the present invention, the reinforcing effect of the reinforcing bar can be increased, and the working efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the entire working process of the first embodiment of the present invention, FIG. 2 is a schematic diagram showing the primary attachment process of the embodiment, and FIG. 3 is the working process shown in FIG. FIG. 4 (E) is a cross-sectional view of the concrete slurry, FIG. 4 is a cross-sectional view of the concrete in the working step (J) shown in FIG. 1, and FIG. 5 is a step of primary adhesion in the second embodiment of the present invention. It is a schematic diagram. 10 ... Rebar, 16 ... Powder, 27E, 27F ... Concrete slurry, 27G, 27J ... Concrete, 31 ... Autoclave.

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁷ Identification code FI E04C 5/01 E04C 5/01

Claims (3)

(57) [Claims] 1. A method according to claim 1, wherein the rebar is preheated to a temperature at which the synthetic resin powder to be attached to the rebar does not melt, and the powder is primarily adhered to the rebar using heat from the preheating. A rust prevention method for a reinforcing steel bar, wherein a concrete slurry wrapped around a reinforcing bar to which a body is attached and solidified into a predetermined shape is cured in an autoclave, and the powder is secondarily attached to both the reinforcing bar and the concrete. Painting method. 2. The method according to claim 1, wherein the primary attachment of the powder to the reinforcing bar gives a charge to the reinforcing bar,
An antirust coating method for a reinforcing bar, wherein the method is performed in a state in which a charge having a polarity opposite to this charge is applied to a powder. 3. The rust prevention of a reinforcing bar according to claim 1 or 2, wherein a powder of a thermosetting synthetic resin which is cured in a heated state is adopted as said powder. Painting method.