JPS6360711B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to pre-heavy anti-corrosion steel driving members for civil engineering, such as steel sheet piles, steel pipe sheet piles, and steel pipe piles, which have been previously coated with a heavy anti-corrosion coating using a urethane-based material. Steel pipe sheet piles are used in facilities such as ports, river revetments, quays, and breakwaters. In the past, it was common to use bare steel pipe sheet piles, but in recent years, they are often used in harbors, 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 become necessary. Measures have become necessary. Up until now, the most common method for preventing corrosion of steel pipe sheet pile structures has been to apply tar epoxy paint, but long-term corrosion prevention effects could not be expected with this method. In other words, even if tar epoxy paint is applied before driving steel pipe sheet piles, the paint film is easily damaged, and scratches and bruises are likely to occur on the paint film during handling or driving. There was a drawback that the parts were easily corroded. 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, you will need to perform drainage work, etc., which will lead to an increase in construction costs. Another method is to apply an underwater curing paint, but this method requires diving work for underwater construction, which has the drawback of increasing costs. As a result of intensive research aimed at resolving the drawbacks of the conventional corrosion protection methods mentioned above, the present inventors have developed a civil engineering preform that does not damage the coating film during handling, pouring, etc., and can maintain its anticorrosion performance over a long period of time. We have developed a heavy corrosion-resistant steel driven member. That is, the present invention provides steel driving members for civil engineering such as steel sheet piles, steel pipe sheet piles, and steel pipe piles coated with urethane elastomer.
A urethane elastomer material made by mixing MDI (4,4' diphenylmethane diisocyanate) and polybutadiene polyol as a polyol. The gist of this invention is a pre-heavy-duty anti-corrosion steel driving member for civil engineering, characterized in that both sides are coated with heavy-duty anti-corrosion coating. The present invention will be explained in detail below. 1 and 2 are partial perspective views showing an embodiment of the pre-heavy anti-corrosion steel pipe sheet pile of the present invention, and in the case of FIG. 1,
A urethane elastomer material with excellent corrosion resistance, impact resistance, abrasion resistance, etc. is applied to both sides of the surface of the steel pipe sheet pile, which is made up of a steel pipe 1 and a steel joint 2 with a circular cross section, which is fixed to both sides in the diametrical direction. In the case of FIG. 2, a heavy anti-corrosion coating layer 3 made of a urethane elastomer material is integrally provided on only one side of the surface of the steel pipe sheet pile. FIG. 3 shows a state where 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 steel joint 4 having a T-shaped cross section is fixed to one side of the steel pipe 1, and a steel joint 4 having a T-shaped cross section is fixed to the steel pipe 1. A joint made of a pair of steel angle members 5 may be fixed to the other side. It goes without saying that heavy corrosion protection can be applied to necessary parts of the surface, 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. MDI (4,4' diphenylmethane diisocyanate) is used as the isocyanate, and polybutadiene polyol is used as the polyol. Since the key point of the present invention is to form a coating especially for the purpose of heavy corrosion protection, an MDI-polybutadiene polyol-based urethane elastomer having the lowest water absorption rate is used. Next, the water absorption values are shown in Table 1.

[Table] This urethane elastomer can be applied by troweling, but it can also be applied by spray if the two liquids, isocyanate and polyol, are fed separately and mixed just before the nozzle and discharged. Furthermore, by adding a catalyst (e.g., digtylated tin di-laurylate), the curing speed after painting can be increased.As a result, a coating of 2 to 3 mm thick can be applied at one time without worrying about sagging. Possible. 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 material is to be used for a long period of time, urethane elastomer materials may Before application, it is necessary to blast the surface of the steel pipe sheet pile with shot, grit, or sand, etc., and condition the surface to a level of Swedish standard SIS-Sa2 1/2 or higher to maintain adhesion. If it will be used in a immersed state for more than 40 years, apply an epoxy primer after blasting.
It is effective to apply a urethane elastomer material on top of the primer after applying it to a thickness of 30 to 50 microns. As an epoxy-based primer, a mixture of bisphenol A type epoxy as the main ingredient and modified aliphatic polyamine as the curing agent in a 2:1 ratio has the best water resistance. This primer can be applied by brush or spray. Since it can be coated with urethane elastomer materials, it has the characteristic of being able to obtain a wide range of film thicknesses from thin to thick by changing the discharge rate and recoating. Therefore, various thicknesses can be selected depending on the purpose of use, usage conditions, period of use, etc. of the steel driving member for civil engineering. For example, if the film is to be placed in seawater and intended to be used for 20 years or more, a film thickness of 2.5 mm or more is appropriate. The surface of urethane elastomer deteriorates when exposed to ultraviolet rays, and yoking (a phenomenon in which it crumbles into powder) occurs, but the amount of this is less than 0.1 mm per year, which poses no practical problem. In the zone (spray zone), solar radiation is strong and there is reflection from the sea surface, and at the same time, the waves wash away the degraded substances on the surface, and the yoking speed becomes faster than in the normal case. In such a case,
The above phenomenon can be prevented by further spray-coating an acrylic urethane material on the surface of the urethane elastomer. 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, epoxy ) 7 and urethane elastomer 8 are sequentially provided, and in the case of FIG.
A primer 7, a urethane elastomer 8, and a weather-resistant material (for example, acrylic urethane) 9 are sequentially provided on the surface of the steel driven member 6, and in the case of FIG. 7. Urethane elastomer 8. Impact resistant material (e.g. polymer cement mortar or resin mortar)
10 are provided in sequence. In addition, in the case of FIG. 9, a primer 7, a urethane elastomer 8, an impact-resistant material 10, and a weather-resistant material 9 are sequentially provided on the surface of the steel driven member 6,
In the case of FIG. 10, a primer 7, a urethane elastomer 8, an impact-resistant material 10, and a colored material 11 are sequentially provided on the surface of a steel driven member 6. Next, examples of the present invention will be shown. The thickness of acrylic urethane can be varied depending on the spray, but a thickness of 100μ is required to ensure durability in the splash zone for 40 years. When used in a splash zone and where there are many driftwood or ships berthed, anti-corrosion performance and impact resistance are required. Under normal circumstances, urethane elastomers have sufficient impact resistance, but if even higher impact resistance is required, a layer of polymer cement mortar or resin mortar is applied on top of the urethane elastomers. Just do it. As polymer cement, acrylic emulsion type and as resin mortar, epoxy type have excellent coating strength and bending performance. Example 1 A steel sheet pile FSP-type was coated with the following coating and its performance was investigated after being immersed in seawater for one year. The results are shown in Table 2.

[Table] 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 urethane elastomer layer, an accelerated outdoor exposure test was conducted using a sunshine weather meter. Ivy. Table 3 shows the coating performance after 4000 hours of weather meter irradiation (equivalent to 16 years of outdoor exposure).

[Table] From the above test results, it has become clear that coating with acrylic urethane provides weather resistance for over 16 years. Example 3 A comparative test was carried out between the steel sheet pile coated in Example 1 and one whose surface of the urethane elastomer layer was coated with an acrylic emulsion polymer cement. Table 4 shows the results of the comparison test.

[Table] From the above results, it can be seen that if the surface of the urethane elastomer is coated with polymer cement, the impact strength can be significantly improved. Next, an FSP-type steel sheet pile with a length of 10 m, which is made by coating both sides with the urethane elastomer material of the present invention, is poured into the soil, and then pulled out to prevent the coating film from forming due to friction with the soil. As a result of investigating the damage, 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 confirmed that the coating had excellent abrasion resistance. As is clear from the above examples, the pre-heavy-duty corrosion-resistant steel driven member for civil engineering according to the present invention has a water absorption rate obtained by mixing MDI (4,4' diphenylmethane diisocyanate) as the isocyanate and polybutadiene polyol as the polyol. Since the steel driven parts are heavily coated with a urethane elastomer material with extremely low corrosion resistance, the steel driven parts can be protected against corrosion for a long period of time, and the coating film of the urethane elastomer material is strong. Therefore, the coating film is not damaged during handling, pouring, etc., and since the tough coating film acts as a protective material against corrosion, corrosion resistance can be maintained for a long period of time. Therefore, the service life of the civil engineering steel structure itself is greatly extended, the cost of anti-corrosion repairs, etc. is reduced, and the total cost including construction work costs and maintenance costs can be significantly reduced. It 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 heavy pre-corrosion protection on both sides, Figure 2 is a perspective view of a steel pipe sheet pile with heavy pre-corrosion protection applied on one side, and Figure 3 shows the steel sheet piles shown in Figure 2 interlocked. 4 and 5 are plan views showing the state in which
The figure is a plan view showing another type of steel pipe sheet pile in which the present invention can be implemented. 6 to 10 are cross-sectional views showing examples of combinations of materials provided on the surface of a steel driven member. In the figure, 1 is a steel pipe, 2 is a steel joint, 3 is an anticorrosive coating layer, 6 is a steel driven member, 7 is a primer,
8 is urethane elastomer, 9 is weather resistant material, 1
0 is an impact resistant material and 11 is a colored material.

Claims (1)

[Claims] 1 Steel sheet pile coated with urethane elastomer,
A urethane elastomer material made by mixing MDI (4,4' diphenylmethane diisocyanate) as the isocyanate and polybutadiene polyol as the polyol in steel driven members for civil engineering such as steel pipe sheet piles and steel pipe piles. A pre-heavy corrosion-resistant steel driven member for civil engineering, such as sheet piles and steel pipe piles, characterized in that one or both sides of the surface of the steel driven member for civil engineering is coated with heavy corrosion protection.