JPS6030727A - Heavily anticorrosive steel driver for civil construction work - Google Patents

Abstract

PURPOSE:To raise the corrosion resistance of steel materials for civil construction work as well as to protect the anticorrosive film formed on the surface of steel materials from damage during handling and driving operations by integrally forming a heavily anticorrosive film of urethane elastomer on the surface of the steel materials, e.g. steel pipe, etc., to be driven. CONSTITUTION:Anticorrosive covering film 18 of urethane elastomer, having excellent corrosion resistance, excellent impact resistance, and excellent wear resistance, is integrally provided through a primer on both sides of the surface of a steel tubular sheet pile consisting of a steel tube 1 and partly notched round steel couplers 2 to be fixed to both sides in the diametrical direction of the steel tube 1. The urethane elastomer used is prepared by mixing an isocyanate and a polyol. Damage to the paint film can thus be prevented during the driving operations, and the corrosion resistance of the sheet pile can be kept for long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that it has been heavily coated with a urethane material in advance.
This relates to driven members made of anti-corrosion steel for civil engineering such as steel sheet piles, steel pipe sheet piles, and steel pipe piles.

Steel pipe sheet piles are used in facilities such as ports, river revetments, quays, and breakwaters. In the past, steel pipe sheet piles were commonly used for detective purposes, but in recent years, they are often used in ports, rivers, etc., which have highly corrosive environments, and the useful life of the structures themselves has become longer, so corrosion protection of steel pipe sheet piles has been adopted. Measures have become necessary.

Until now, the most common method for preventing corrosion of steel pipe sheet pile structures was to apply cool epoxy paint, but this method could not provide long-term corrosion protection. In other words, even if tar epoxy paint is applied before all steel pipe sheet piles are placed, the paint film is easily damaged, such as scratches and bruises, which can easily occur during handling or pouring. It had the disadvantage of being prone to corrosion from uneven parts.

On the other hand, there is a method of painting after pouring, but this method is not suitable because the underwater part cannot be painted and the corrosion protection is only applied to the underwater part. Furthermore, if you try to apply it to the underwater part, it will be necessary to carry out drainage work, etc., which will lead to an increase in construction costs.

There is also a method of completely applying underwater curable paint, but this method requires diving work for underwater construction and has the disadvantage of increasing costs.

As a result of intensive research aimed at resolving the drawbacks of the conventional corrosion protection methods described above, the present inventors have developed a civil engineering preform that does not damage the coating film during handling, pouring, etc., and maintains its anticorrosion performance over a long period of time. We have developed a heavy corrosion-resistant steel driven member.

That is, the present invention is characterized in that a heavy anti-corrosion coating layer of a urethane elastomer material is integrally provided on one or both sides of the surface of a steel driven member for civil engineering such as a steel sheet pile, a steel pipe sheet pile, or a steel pipe pile. The gist is a pre-heavy-duty anti-corrosion steel driving member for civil engineering.

The present invention will be explained in detail below. 1 and 2 are partial perspective views showing embodiments of the pre-heavy-duty anti-corrosion steel pipe sheet pile of the present invention. In the case of FIG. An anti-corrosion coating layer 3 made of a urethane elastomer material with excellent corrosion resistance, impact resistance, abrasion resistance, etc. is integrally provided on both sides of the surface of the steel pipe sheet pile consisting of a partially notched circular steel joint 2. In the case of FIG. 2, a heavy anti-corrosion coating layer 6 made of a urethane elastomer material is integrally provided only on one side of the surface of the steel pipe sheet pile.

FIG. 3 shows a state in which the pre-heavy anti-corrosion steel pipe sheet piles shown in FIG. 2 are interlocked with each other.

When carrying out the present invention, as shown in FIG. Alternatively, as shown in FIG. 5, a T-shaped steel joint 4 may be fixed to one side of the steel pipe 1, and a steel joint 4 having a T-shaped cross section may be fixed to the steel pipe 1. A joint made of a pair of steel angle members 5 may be completely fixed to the other side.

It goes without saying that heavy corrosion protection can be applied to areas of the surface where it is necessary, including the longitudinal direction of the steel pipe sheet piles. Furthermore, the method can be applied not only to steel pipe sheet piles but also to steel sheet piles, steel pipe piles, etc.

The aforementioned urethane elastomer material is formed by mixing isocyanate and polyol.

As the isocyanate, TDI (4,4' diphenylmethane diisocyanate), MIo (4,4' diphenylmethane diisocyanate), HMDI (hexamethylene diisocyanate), XDI (xylene diisocyanate), etc. can be used. As a polyol,
PPG (polypropylene glycol), PTMG (polytetramethylene glycol), polyester (adipate type), polymeric diene polyol, castor oil, etc. can be used.

By selecting one of these incyanates and polyols, urethane elastomer materials having various performances can be obtained. Since the key point of the present invention is to form a coating especially for the purpose of heavy corrosion protection, in this invention,
It is desirable to use MDI-polybutadiene polyol-based urethane elastomer, which has the lowest water absorption. Next, the water absorption values are shown in Table 1.

Table-1 Water absorption rate: Measured according to JISK7114, immersed in water at 80°C for 7 hours. This urethane elastomer can be applied with a trowel, but the two liquids, incyanate and polyol, are fed separately.
Spray painting is possible by mixing and discharging just before the nozzle. .

Also catalysts (e.g. digtyl tin di-laurylate)
By adding all the components, the curing speed after coating can be increased. As a result, there is no need to worry about sagging, and you can use 2-3 times at once.
It is possible to paint very thickly.

Urethane elastomer materials will adhere to the surface of steel pipe sheet piles even if mill scale is still formed (it is also used as an adhesive), but if the surface is to be used for a long period of time, it should be In addition, it is necessary to plaster the surface of the steel pipe sheet pile with shot, glint, or sand in order to maintain the adhesion of the sheet pile. Furthermore, if the product is to be used after being immersed in seawater for more than 40 years, apply an epoxy primer for 60 minutes after plasting.
It is effective to apply the entire urethane elastomer material over the primer after applying the primer to a thickness of 0 to 50 tt.

As an epoxy primer, bisphenol A type epoxy is used as the main agent and modified aliphatic polyamine is used as the curing agent.
A mixture of 2:1 has the best water resistance. This primer can be applied by brush or spray.

Since it can be coated with urethane di-stomer materials, it has the feature of being able to obtain a wide range of film thicknesses, from thin to thick, by changing the discharge rate and overcoating. Therefore, various thicknesses can be selected depending on the purpose of use, usage conditions, usage period, etc. of the steel driven member for civil engineering. For example, if the film is to be cast in seawater and intended to be used for 20 years or more, a film thickness of 25 mm or more is appropriate.

In addition, the surface of urethane distoner deteriorates due to ultraviolet rays, and chalking (a phenomenon in which it crumbles into powder) occurs, but the amount of chalking is less than 0.1 mm per year, which poses no practical problem. In the zone (splash zone), there is strong sunlight and reflection from the sea surface,
The waves wash away the deteriorating substances on the surface, making the chalking speed faster than in normal conditions. In such a case, the above phenomenon can be prevented by further spray-coating the entire surface of the urethane distomer with an acrylic urethane material.

As the acrylic urethane material, a material obtained by reacting an acrylic polyol with a urethane prepolymer containing terminal isocyanate groups is used.

6 to 10 show examples of combinations of steel driven members and materials provided on their surfaces. In the case of FIG. 6, the surface of the steel driven member 6 is coated with a primer (for example, an epoxy ) 7 and urethane elastomer 8 are sequentially provided, and in the case of FIG. 7, primer 7, urethane elastomer 8. A weather-resistant material (for example, acrylic urethane) 9 is sequentially provided, and in the case of FIG. 8, a primer 7, a urethane elastomer 8. An impact resistant material 10 (for example polymer cement mortar or resin mortar) is then provided.

In the case of FIG. 9, primer 7, urethane elastomer 8. Impact resistant material 10.
Weather-resistant materials 9 are sequentially provided, and in the case of FIG. 10, primer 7, urethane elastomer 8. Impact resistant material 10° and colored material 11 are provided in sequence.

Next, examples of the present invention will be shown.

The thickness of acrylic urethane can be varied by spraying, but a thickness of 100μ is required to ensure durability in the splash zone for 40 years. If it is used in a splash zone and there are many driftwood or ships berthed,
Impact resistance is required as well as corrosion resistance. Under normal circumstances, urethane elastomer has sufficient impact resistance, but if even higher impact resistance is required, use polymer cement mortar or 77 mortar on top of the urethane elastomer. All you have to do is add layers. As a polymer cement, an acrylic emulsion type is superior, and as a resin mortar, an epoxy type is superior in coating film strength and bending performance.

Example 1 The following 'It' was applied to steel sheet pile FSP-J type, and the performance was investigated after being immersed in seawater for one year. The results are shown in Table 2.

Table 2 As a result, it was found that the urethane elastomer had good performance even after being immersed in seawater for one year.

Example 2 In order to compare the weather resistance of the steel sheet pile coated in Example 1 and that with an acrylic urethane material applied to the surface of the single layer of urethane elastomer, an accelerated outdoor exposure test was conducted using a sunshine weather meter. . Table 3 shows the coating performance after 4000 hours of weather meter irradiation (equivalent to 16 years of outdoor exposure).

Table 3 From the above test results, it has become clear that coating with acrylic urethane provides weather resistance of 16 years or more.

Example 3 Acrylic emulsion polymer cement was applied to the surface of the steel sheet pile coated in Example 1 and its urethane elastomer layer)
A comparative test with a coated one was conducted. Table 4 shows the results of the comparison test.

Table 4 From the above results, it can be seen that if the surface of the urethane elastomer is coated with polymer cement, the impact strength is significantly improved.

Next, a PSP-■ type steel sheet pile with a length of 10 m and a heavy corrosion-resistant steel sheet pile coated with the urethane distomer material according to the present invention on both sides was driven into the soil, and then pulled out and coated by friction with the soil. As a result of investigating the state of damage to the film, it was found that there were only a few scratches on the outermost surface of the coating (the depth of the scratches could not be measured), and it was also confirmed that the film had excellent abrasion resistance.

As is clear from the above examples, the pre-heavy-duty anti-corrosion steel driving member for civil engineering according to the present invention does not cause any damage to the coating film during handling, pouring, etc., and the tough coating film can be used as a protection material against corrosion. Therefore, long-term corrosion resistance can be maintained. Therefore, the service life of civil engineering steel structures themselves will be greatly extended, the cost of anti-corrosion repairs, etc. will be reduced, and the total cost, including construction costs and maintenance costs, will be significantly reduced. becomes possible. Moreover, since a heavy anti-corrosion coating has been applied in advance, there is no need for on-site anti-corrosion construction, and the construction period in corrosive environments such as ports and rivers can be significantly shortened. Furthermore, by changing the color of the coating film or applying colored paint as a top coat, the present invention has great effects such as harmonizing with the surrounding environment and maintaining the aesthetic appearance.

[Brief explanation of drawings]

Figure 1 is a perspective view of a steel pipe sheet pile with pre-heavy anti-corrosion treatment on both sides.
Figure 2 is a perspective view of a steel pipe sheet pile with pre-heavy corrosion protection applied to one side.
FIG. 6 is a plan view showing a state in which the steel sheet piles shown in FIG. 2 are interlocked, and FIGS. 4 and 5 are plan views showing other types of steel pipe sheet piles in which the present invention can be practiced. Figures 6 to 1
FIG. 0 is a sectional view showing an example of a combination of materials provided on the surface of a steel driving member. In the figure, 1 is a steel pipe, 2 is a steel joint, the filter is an anti-corrosion coating layer, 6 is a steel driven member, 7 is a primer, 8 is a urethane elastomer, 9 is a weather-resistant material, and 10 is an impact-resistant material. Material, 1
1 is a coloring material. Continued from page 1 @ Inventor Tomihiko Otsuki Kimitsu 1, Kimitsu City @ Inventor
Kazuyuki Suzuki Kimitsu 1, Kimitsu City, Nippon Steel Corporation, Kimitsu Works, Nippon Steel Corporation, Kimitsu Works, Nippon Steel Corporation

Claims (1)

[Claims] A pre-heavy construction material for civil engineering, characterized in that a heavy anti-corrosion coating layer of urethane elastomer material is integrally provided on one or both sides of the surface of steel driven members for civil engineering such as steel sheet piles, steel pipe sheet piles, and steel pipe piles. Corrosion-resistant steel driven parts.