JPH0340928Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a corrosion-proofing reinforcement structure for members driven into the underwater ground, such as steel pipe piles, steel sheet piles, or steel pipe sheet piles, which are driven into the underwater ground.

[Prior art]

Conventionally, as an anti-corrosion reinforcement structure for a member driven into the submerged ground, as published in Publication No. 60-374, there is a reinforcement structure between a steel driven member driven into the submerged ground and an anti-corrosion cover that covers it. In a corrosion-proof reinforced structure filled with a time-curable filler, a corrosion-proof reinforced structure is known in which a super water-absorbent and expandable resin layer is interposed between the corrosion-proof cover and the time-curable filler.

[Problem that the invention attempts to solve]

However, in the case of the conventional anti-corrosion reinforced structure,
When the super water-absorbing and swelling resin layer absorbs water, it expands.
A large internal pressure acts on the anti-corrosion cover, so if the anti-corrosion cover is made of a material with low tensile strength such as a cement-based material, cracks may occur in the anti-corrosion cover or the cover may be damaged.

[Purpose of the invention, structure]

The purpose of this invention is to provide an anti-corrosion reinforcing structure for members driven into the submerged ground, which can advantageously solve the above-mentioned problems. A cover 1 is disposed so as to face the corrosion-protected reinforced portion of a steel driven member 2 driven into the underwater ground, and a water-absorbing softening viscoelastic water-stopping layer 3 is provided on the inner surface of the protective cover 1.
Corrosion prevention of a member driven into the underwater ground, characterized in that a cement-based filling layer 4 that hardens over time is interposed between the driven member 2 and the water-absorbing softening viscoelastic water stop layer 3. It has a reinforced structure.

〔Example〕

Next, this invention will be explained in detail using illustrated examples.

4 and 5 show a cover unit 5 with a water-absorbing, softening, viscoelastic water-stopping layer used in an embodiment of this invention, which is made of a mixed material of glass fiber or synthetic fiber and concrete or mortar and is shaped like a semi-cylindrical member. A protective cover 1 made of a fiber-reinforced cement material is formed, and a water-absorbing, softening, viscoelastic water-stopping layer 3 is integrally provided on the inner peripheral surface of the protective cover 1 by coating or spraying. This water-absorbing, softening viscoelastic water-stopping layer 3 is hard when not absorbing water, but softens upon water absorption and exhibits viscoelasticity and water-stopping properties.

1 to 3 show an anti-corrosion reinforcing structure for a member driven into the submerged ground according to an embodiment of this invention using a cover unit 5.
The outer circumferential surface of the steel driven member 2, which is made of a steel pipe pile that is driven into the concrete slab and supports the structure 7 such as a concrete floor slab, is coated with corrosion-protected reinforced parts such as corroded parts of the steel driven member 2. At the bottom, a plurality of steel brackets 8 are fixed by welding, and a two-part steel annular bottom plate 9 surrounding the steel driving member 2 is attached to the brackets 8.
The pair of semi-cylindrical cover units 5 are placed on the annular bottom plate 9 and are placed on the annular bottom plate 9, and the pair of semi-cylindrical cover units 5 are placed so as to surround the entire circumference of the corrosion-protected reinforced portion of the steel driven member 2. Each cover unit 5 is tightened and connected by a plurality of stainless steel bands 10 arranged at intervals in the vertical direction, and is connected to the corrosion-protected reinforced portion of the steel driven member 2 and the water absorption softening viscoelastic stopper. The annular portion between the water layer 3 and the water material layer 3 is injected and filled with concrete, cement mortar, etc., and a cement-based time-hardening filler layer 4 is integrally provided.

When implementing this invention, the materials constituting the water absorbing and softening viscoelastic water stop layer 3 include, for example, a urethane bond bonded to an aliphatic group (however, the aliphatic group is bonded to NH of the urethane bond) and an aromatic A water-absorbing, softening, viscoelastic water-stopping material is used which contains an NCO-terminated urethane prepolymer A having an NCO group bonded to the core and optionally an anti-sag agent and a solvent.

Further, as said A, for example, an OH-terminated urethane prepolymer a made of an aliphatic polyisocyanate and an excess polyether polyol and an NCO-terminated urethane prepolymer of an aromatic polyisocyanate is used, and as said a, A product obtained by reacting an aliphatic polyisocyanate and a polyether polyol at a NCO/OH ratio of 1/1.2 to 1/8 is used.

In addition, as the above A, aromatic polyisocyanate and the above a are combined with an NCO/OH ratio of 1.4/1 to 3/
The polyether polyol may be reacted at a ratio of 1 to 1, and the polyether polyol may have a ratio of 50 to 1, based on the weight of the total oxyalkylene.
One having an oxyethylene content of 100% may be used, or an oxyethylene/oxypropylene copolymer polyether polyol may be used.

Further, as the polyether polyol, for example, one having an average hydroxyl equivalent of 800 to 4000 is used, and as the above-mentioned A, for example, NCO% is
Use one with a content of 0.05 to 7%.

The average hydroxyl equivalent of the polyether polyol is usually 800 to 4,000, preferably 1,000 to 3,000.
If the average hydroxyl equivalent is less than 800, the water absorption rate is insufficient,
If it exceeds 4000, shape retention during water absorption and softening will decrease.

In the polyether polyol, the oxyethylene content is preferably 50 to 100%, particularly preferably 60%, based on the total weight of all oxyalkylenes.
~85%. If the oxyethylene content is less than 50%, the water absorption rate will be insufficient.

In addition to polyoxyethylene polyols and/or copolymerized polyether polyols, other polyether polyols such as polyoxypropylene polyols can also be used together with these polyether polyols, but in this case, the oxyethylene content in the combined product is Similarly to the above, it is preferably 50 to 100%, particularly 65 to 85% of the total weight of all oxyalkylenes.

In the OH-terminated urethane prepolymer a made from aliphatic polyisocyanate and excess polyether polyol, the NCO/OH ratio of the aliphatic polyisocyanate and polyether polyol is usually 1/1.2 to 1/8, preferably 1/8. It is 1.5 to 1/4. When the NCO/OH ratio exceeds 1/1.2, the OH-terminated urethane prepolymer becomes highly viscous, making it difficult to handle in practice. Also, the NCO/OH ratio is 1/
When it is less than 8, base resistance decreases.

The OH-terminated urethane prepolymer a can be obtained by reacting an aliphatic polyisocyanate and a polyether polyol at the above NCO/OH ratio in a conventional manner. The reaction temperature is usually
The temperature is 60 to 130°C, preferably 70 to 120°C, and the reaction time is usually 4 to 20 hours, preferably 6 to 15 hours.

The prepolymerization reaction can also be carried out in a solvent depending on the case. Examples of this solvent include polar solvents that do not have active hydrogen, such as ketone solvents (methyl ethyl ketone, methyl isobutyl ketone, etc.), etherified or esterified cellosolve solvents (dimethyl cellosolve, methyl cellosolve acetate, etc.), and two or more of these solvents. A mixture of The weight of the solvent used is usually 0 to 100 parts by weight of the OH-terminated urethane prepolymer.
-120 parts by weight, preferably 10-80 parts by weight.

Further, the prepolymerization reaction can be carried out in the presence of a catalyst depending on the case. This catalyst is
Conventionally known catalysts that generally promote the reaction between isocyanate groups and active hydrogen compounds, such as organometallic catalysts (dibutyltin dilaurate, lead octylate, stannath octoate, etc.) and/or tertiary amine compounds (triethylamine, triethylenediamine, etc.) etc. can be used. The average hydroxyl equivalent of the obtained less than OH urethane prepolymer a is usually 900 to 25,000, preferably 1,300 to 9,300.

Examples of the aromatic polyisocyanate giving the terminal NCO bonded to the aromatic nucleus of the less than NCO urethane prepolymer A include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), crude MDI, and modified MDI. 〔for example
MDI modified to contain a carbodiimide group, a uretdione group, or a uretonimine group (as described in Japanese Patent Publication No. 55-27098)] and mixtures of two or more of these may be mentioned. Preferred among these are TDI and MDI.

In addition, in the NCO-less urethane prepolymer A of the less-OH urethane prepolymer a and aromatic polyisocyanate, the NCO/less-OH urethane prepolymer a and the aromatic polyisocyanate are
The OH ratio is usually 1.4/1 to 3/1, preferably 1.6/
It is 1 to 2.5/1. If the NCO/OH ratio is less than 1.4/1, shape retention during water absorption and softening will decrease.
If it exceeds 3/1, the water absorption rate will be insufficient.

NCO-terminated urethane prepolymer A can be obtained by reacting OH-terminated urethane prepolymer a and aromatic polyisocyanate at the above NCO/OH ratio. Its reaction temperature is usually 60~100
The reaction time is usually 4 to 12 hours, preferably 6 to 10 hours.

The reaction to obtain this NCO-terminated urethane prepolymer A can optionally be carried out in the presence of a solvent and/or a catalyst, as in the case of obtaining the OH-terminated urethane prepolymer a, and the preferred solvent and its amount are also the same. , and preferred catalysts are also the same.

The obtained NCO-terminated urethane prepolymer A
NCO% is usually 0.05-7%, preferably 0.1%-4
%.

The molar ratio of aliphatic polyisocyanate to aromatic polyisocyanate in the total polyisocyanate used to obtain NCO-terminated urethane prepolymer A is usually 1:0.7 to 20, preferably 1:0.8.
~9.

The concentration of urethane bonds bonded to aliphatic groups in NCO urethane prepolymer A (if a solvent is used, the composition excluding the solvent) is usually 2.5 × 10 ^-5 mol/g
~1.0×10 ^-3 mol/g, preferably 7.0×10 ^-5 mol/
g ~ 6.5×10 ^-4 mol/g, and the concentration of urethane bonded to the aromatic nucleus is usually 5.5×10 ^-5 mol/g ~ 3.0
×10 ^-3 mol/g, preferably 1.5 × 10 ^-4 mol/g ~
It is 2.0×10 ⁻³ mol/g.

The NCO-terminated urethane prepolymer A can be used in combination with other NCO-terminated urethane prepolymers, if necessary. The ratio of A and B can be varied, but A should be 20% by weight or more, especially 50% by weight of the total amount of NCO-terminated urethane prepolymer.
It is preferable to contain the above amount.

In addition to the NCO-terminated urethane prepolymer, the coating material for forming the water absorbing and softening viscoelastic water stop layer 2 can contain an anti-sagging agent and a solvent as necessary. Examples of anti-sag agents include finely powdered silica, asbestos, and glass fiber. The weight of the anti-sagging agent used is
The amount is usually 0 to 20 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of the NCO-terminated urethane prepolymer.

Examples of the solvent include solvents that can be used in the prepolymerization reaction, such as ketone solvents, ester solvents, ethers or esterified cellosolve solvents, and mixtures of two or more thereof. The weight of the solvent is usually 0 to 120 parts by weight, based on 100 parts by weight of the NCO-terminated urethane prepolymer, as in the prepolymerization reaction.
Preferably it is 10 to 80 parts by weight.

The coating material may further contain other additives such as fillers, colorants, antioxidants, plasticizers, and the like. As a filler,
For example, bentonite, calcium carbonate, clay, talc, etc. Colorants include titanium white, carbon black, red iron, chrome green, etc. Antioxidants include hindered phenols, hindered amines, etc. Plasticizers include:
Examples include dioctyl phthalate, dibutyl phthalate, and dioctyl adipate. The total weight of other compounding agents is usually 0 to 50 parts by weight based on 100 parts by weight of the NCO-terminated urethane prepolymer.
Preferably it is 0 to 30 parts by weight.

When applying the coating agent to the inner surface of the protective cover, examples of the coating method include spray coating, brush coating, spatula coating, and the like. And the film thickness is usually 100μ~2.5mm, preferably 500μ~
It is 2mm.

After the coating material is applied to the inner surface of the protective cover, it is necessary to cure it with moisture in the atmosphere, thereby exhibiting excellent water absorption and softening properties, and
Other methods, such as curing in water, do not provide sufficient shape retention.

Curing conditions for moisture curing can be varied, but are usually at room temperature for 5 hours to 2 days.

The coated and cured coating material has the property of softening when it comes into contact with water, and the coating material has excellent base resistance after being coated and cured [in a base (caustic soda, ammonia, organic amine, etc.) aqueous solution]. It can withstand use even in basic water such as seawater, and has excellent durability even in acidic water.

Furthermore, the coating material applied to the inner surface of the protective cover and softened by water absorption has good watertightness and does not peel off when softened by water absorption, and furthermore, the water absorption capacity does not decrease due to repeated water absorption and softening and drying. have

In addition, the coating material has excellent water absorption and softening properties not only in fresh water, but also in water such as seawater, hard water, and water containing metal ions such as calcium and iron, which have conventionally had low water absorption and softening properties. The coating material exhibits water absorption and softening properties, and moreover, in the metal ion-containing water, the coating material exhibits water absorption and softening properties equivalent to or higher than that in fresh water.

By appropriately setting the formulation of the coating material within the above-mentioned range, the viscoelastic water stop layer 2 when softened by water absorption.
The hardness can be adjusted.

The surface cleaning condition of the inner surface of the protective cover before applying the coating material is only required to remove moisture, oil, and other substances that significantly impair the adhesion of the coating material, and the cost of preparing the surface to be coated is extremely low. The coating material can be applied by spraying or brushing and does not require any special coating equipment, making the coating cost extremely low.

To apply the coating material to the inside surface of the protective cover,
This may be done at the factory or at a suitable yard near the site.

When storing a protective cover with a water-absorbing, softening, viscoelastic water-stopping layer outdoors for a long period of time, the water-absorbing, softening, viscoelastic, water-stopping layer 2 will soften when it absorbs rainwater, so it should be pasted with waterproof tape or covered with a waterproof sheet. There is a need.

If waterproof tape is attached, just peel it off immediately before installing the protective cover.

Even if the coating material absorbs water and becomes soft during storage of the protective cover, when released from the moisture environment, it releases (evaporates) the absorbed moisture into the air and returns to its original hardened form. Therefore, even if the coating material absorbs water and softens when it comes into contact with rainwater during storage, if the construction process allows enough time to release the absorbed moisture, wrap it with waterproof tape or use a waterproof sheet. There is no need to cover it.

A reinforcing member such as a reinforcing bar may be embedded in the filler layer 4, or a dowel fixed to the steel driven member 2 may be embedded in the filler layer 4.

In the case of the above embodiment, two semi-cylindrical protective covers 1 are joined to form a cylindrical protective cover, but three or more protective covers 1 having an arcuate cross section are joined to form a cylindrical protective cover. A protective cover may also be provided.

This invention can also be implemented for anti-corrosion reinforcement of steel pipe sheet pile walls or steel sheet pile walls.

[Effect of idea]

According to this invention, when the seawater that has permeated the protective cover 1 made of fiber-reinforced cement material penetrates into the inside of the water-absorbing, softening viscoelastic water-stopping layer 3, the water-absorbing, softening, viscoelastic water-stopping layer 3 becomes water-absorbing and softening. It exhibits viscoelasticity, but when the water-absorbing softening viscoelastic water-stopping layer 3 is saturated with seawater, further penetration of seawater is blocked, and Cl ^-1 ions recrystallize on the surface of the water-absorbing softening viscoelastic water-stopping layer 3. Therefore, the Cl ^-1 ions that destroy the stable rust layer formed on the surface of the steel driven member 2 by the alkaline action of the cement-based time-hardening filler layer 4 are removed by water absorption and softening viscoelastic stopper. Water can be blocked on the surface of the water layer 3, and therefore the anti-corrosion effect can be exhibited for a long time, and the breathing water generated along the inner surface of the protective cover 1 made of fiber-reinforced cement material can be absorbed and softened by the viscoelasticity. Water can be absorbed by the water stop layer 3 to reduce breathing, and the water-permeable pores generated inside the cement-based time-hardening filler layer 4 can be reduced to improve the watertightness of the anti-corrosion structure. can be installed, and a protective cover 1
Since the cement material constituting the protective cover 1 is reinforced with fibers, the strength of the protective cover 1 can be increased. In addition, since the water absorption and softening viscoelastic water stop layer 3 is interposed between the protective cover 1 and the filler layer 4, expansion cracks and shrinkage cracks that occur in the filler layer 4 as the filler layer 4 hardens are prevented. It is possible to prevent cracks that occur in the filler layer 4 due to mistakes in mixing management and construction management from propagating to the protective cover 1, and to prevent bending moments and torsional moments that act on the steel driven member 2 from absorbing water. Since it is blocked by the softened viscoelastic water stop layer 3 and hardly transmitted to the protective cover 1, it is possible to prevent cracks from occurring in the protective cover 1, and furthermore, seawater that permeates into the protective cover 1 from the outside is prevented. Seawater containing corrosion-promoting substances such as chloride ions and sulfate ions is
It is possible to prevent the cement-based time-hardening filler layer 4 from penetrating and degrading the filler layer 4 or corroding the steel driven member 2, and also prevents driftwood etc. from colliding with the protective cover 1. At this time, the water-absorbing, softening, viscoelastic water-stopping layer 3 exhibits a buffering effect, so that effects such as being able to prevent cracks from occurring in the protective cover 1 can be obtained.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention, in which Fig. 1 is a cross-sectional plan view showing the anti-corrosion reinforcement structure of the member driven into the submerged ground, Fig. 2 is an enlarged sectional view taken along the line A-A in Fig. 1, Fig. 3 is a vertical cross-sectional side view of a steel driven member made of steel pipe piles supporting a structure with anti-corrosion reinforcement applied, and Fig. 4 is a side view of a cover unit used in an embodiment of this invention. Floor plan, 5th
The figure is a longitudinal side view. In the figure, 1 is a protective cover made of fiber-reinforced cement-based material, 2 is a steel cast member, 3 is a water-absorbing softening viscoelastic water stop layer, 4 is a cement-based time-hardening filler layer,
5 is a cover unit with a water absorption softening viscoelastic water stop layer;
7 is a structure, 8 is a steel bracket, and 9 is a steel annular bottom plate.

Claims (1)

[Scope of utility model registration request] A protective cover 1 made of a fiber-reinforced cement-based material is disposed so as to face the corrosion-protected reinforced portion of a steel driven member 2 driven into the underwater ground, and the inner surface of the protective cover 1 is made of water-absorbing, softening, viscoelastic water-stopping material. A member for driving into the submerged ground, characterized in that a layer 3 is provided on the body, and a cement-based time-hardening filling layer 4 is interposed between the driving member 2 and the water-absorbing, softening, viscoelastic water-stopping layer 3. Anti-corrosion reinforced structure.