JP2007261921A - Grout material for underwater application - Google Patents

Abstract

[PROBLEMS] To provide high underwater separability and high thixotropy even when used for injection into a cavity in which water exists, in particular, a marine structure such as a revetment wall, a port structure or the like, which is in contact with seawater or a cavity. Providing grout materials for underwater construction.
A grout material for underwater construction comprising at least cement, water, crosslinked acrylic polymer particles, and an alkyl ether-modified cellulose resin, wherein the weight ratio of water to the cement is 40/100 to 60/100. The weight ratio of the crosslinked acrylic polymer particles to the water is 1/400 to 1/100, and the weight ratio of the alkyl ether-modified cellulose resin to the water is 1/1000 to 1/100. A characteristic grouting material for underwater construction.
[Selection figure] None

Description

  The present invention relates to a grout material for underwater construction applied to an injection point in contact with seawater. More particularly, the present invention relates to an underwater construction grout material used for pouring and placing in a cavity, gap, or the like in contact with seawater, such as backfilling a revetment wall of an ocean structure, a harbor structure or the like.

  Conventionally, when constructing offshore structures and harbor structures, construction work has been carried out in which cement and concrete are placed in the water. However, in placing concrete mixed on land, the concrete is in dynamic contact with water. Then, separation of the concrete occurs easily, and the placed concrete has a deteriorated quality with a non-uniform composition, and the separated cement paste part diffuses into the water and significantly pollutes the water. For example, concrete is used in which high-viscosity water-soluble resin such as cellulosic resin is added to improve the inseparability in water (for example, see Patent Documents 1 to 3).

On the other hand, as a material for filling voids or cavities in concrete structures in the civil engineering / architecture field, as a backfilling material for tunnels, etc., that is, as a grout material, air in which air bubbles are mixed in a suspension mainly composed of cement. A mixture of mortar, cellulose-based water-soluble polymer resin (see, for example, Patent Document 4), bentonite (see, for example, Patent Document 5), aluminum salt, water glass, or the like is used.
JP 58-69760 A JP 58-115051 JP 60-260456 A JP 09-263438 A JP 2001-240890 A

  By the way, in ocean structures such as revetment walls and harbor structures, the seabed and the ground behind the structure may be eroded by waves, creating cavities. These underwater cavities need to be filled with cement etc. However, in the case of underwater non-separable cement and high-viscosity water-soluble resin such as cellulosic resin used in the above-mentioned existing underwater non-separable concrete, etc. Due to the problem, it is not possible to achieve both sufficient inseparability in water and filling property in a practical blending range.

  Existing underwater non-separable concrete does not require compaction after being placed in water, so it has self-leveling properties, such as cellulosic resin used in such underwater cloth separable concrete. Water-inseparable cement with high-viscosity water-soluble resin added to cement, etc. has self-leveling properties as well, but if such a material with good fluidity is used for filling the cavity, cracks in the filling area and lining There is a problem that cracks, deviations from joints, and the like occur, and a filling amount larger than expected is required, or gaps are generated and the designed strength cannot be obtained.

As an existing grout material, there is a mixture of air mortar mixed with bubbles, cellulose-based water-soluble polymer resin, bentonite, aluminum salt, water glass and the like in a suspension mainly composed of cement. Of these, the grout material in which a cellulose-based water-soluble polymer compound is mixed in a suspension mainly composed of air mortar or cement is too fluid as well as non-separable cement in water. And deviations from gaps are likely to occur. In addition, plastic grout mixed with suspension containing bentonite, aluminum salt, water glass, etc. as the main material is suitable for filling cavities on land, but is not sufficiently separable in water. In the filling of a cavity in which water exists, for example, a cavity into which seawater flows, there is a problem that the environment is contaminated due to material deviation or material separation due to flowing water, or gaps are generated and the designed strength cannot be obtained.
Therefore, the object of the present invention is to have high water inseparability even when used for injection into a cavity in which water exists, in particular, a marine structure such as a seawall, a harbor structure or the like in contact with seawater or a gap or the like. An object of the present invention is to provide a grout material for underwater construction having high thixotropy.

As a result of intensive studies to solve the above problems, the present inventors have used a specific cross-linked acrylic polymer particle and an alkyl ether-modified cellulose resin in a specific ratio, so that high water inseparability and high thixotropic properties are obtained. The present inventors have found that a grout material for underwater construction having a water content can be obtained and completed the present invention.
That is, the present invention is a grout material for underwater construction comprising at least cement, water, crosslinked acrylic polymer particles, and an alkyl ether-modified cellulose resin, wherein the weight ratio of water to the cement is 40/100 to 60/100. The weight ratio of the crosslinked acrylic polymer particles to the water is 1/400 to 1/100, and the weight ratio of the alkyl ether-modified cellulose resin to the water is 1/1000 to 1/100. The present invention provides a grouting material for underwater construction characterized by this.

  Since the grout material for underwater construction of the present invention has good underwater inseparability and high thixotropy, cavities in contact with seawater such as cavities in which water exists, especially marine structures such as revetment walls, harbor structures, etc. Even if injected into a gap or the like, there is no material deviation or material separation caused by running water.

Next, details necessary for carrying out the present invention will be specifically described.
The grout material for underwater construction of the present invention is made of cement, water, crosslinked acrylic polymer particles, and alkyl ether-modified cellulose resin, and contains aggregate, filler, and foam as necessary.

  As cement used for the grout material for underwater construction of the present invention, normal, early strength, ultra-early strength, white, sulfate resistant, moderate heat, low heat, etc., various Portland cements, at least one of the above Portland cement and fly ash, etc. And mixed cement, jet cement, special cement such as alumina cement, and cement-based solidified material.

The crosslinked acrylic polymer particles used in the present invention are water-insoluble particles composed of an acrylic polymer having a crosslinked structure in the molecule, and absorb and swell water several hundred times its own weight. is there. Such polymer particles that absorb and swell water several tens of times their own weight include those having a carboxylic acid group as a hydrophilic group, such as a polymer of (meth) acrylic acid having a crosslinked structure. Such polymer particles may release water once absorbed by the action of multivalent ions such as calcium ions and magnesium ions in the cement. The crosslinked acrylic polymer particles used in the present invention preferably have a sulfonic acid group and / or an acrylamide group in the molecule because of their excellent ability to absorb water containing polyvalent ions.
Such crosslinked acrylic polymer particles containing a sulfonic acid group and / or an acrylamide group include, for example, (i) a sulfonic acid group-containing monomer and / or (ii) an acrylamide monomer, and (iii) ( Polymer particles obtained by polymerizing a (meth) acrylic acid monomer and, if necessary, another polymerizable monomer, if necessary, three-dimensionally cross-linking using a cross-linking agent, and polymerizing Is mentioned. The ratio of the raw materials is preferably 50 mol% or more, more preferably 50 to 95 mol% in total of (i) and (ii), and (iii) (meth) acrylic acid monomer or salt 5 It is used at a ratio of mol% or less.
The sulfonic acid group-containing acrylic monomer is a sulfonic acid group-containing acrylamide monomer, and examples thereof include 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamide-2-methylpropanesulfonic acid, and the like. be able to.

Examples of the sulfonic acid group-containing acrylamide monomer include alkali metal salts, alkaline earth metal salts, ammonium salts such as 2-acrylamido-2-methylpropanesulfonic acid and 2-methacrylamide-2-methylpropanesulfonic acid. Etc. Examples of the alkali metal salt include sodium salt, potassium salt, lithium salt, and rubidium salt. Examples of the alkaline earth metal salt include calcium salt and magnesium salt. Of these, alkali metal salts such as sodium salt, potassium salt, lithium salt and rubidium salt of 2-acrylamido-2-methylpropanesulfonic acid are particularly preferable.
Examples of the acrylamide monomer (ii) include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide and the like. Of these, (meth) acrylamide is preferred.
The polymers obtained by polymerizing the mixture of monomers may be self-crosslinked without using a crosslinking agent, but can be crosslinked using a crosslinking agent.

  The crosslinked acrylic polymer particles used in the present invention are preferably spherical particles having an average particle size of 0.1 to 50 μm, more preferably 15 to 30 μm. If the average particle size exceeds 50 μm, the thickening effect is lowered, which is not preferable. If the average particle size is less than 0.1 μm, the viscosity when the crosslinked acrylic polymer particles are added to water is too high, and mixing with other materials becomes difficult, which is not preferable.

The reason why the thixotropic property appears when the crosslinked acrylic polymer particles used in the present invention are added to cement milk is considered as follows.
Cross-linked acrylic polymer particles that have been used as cement additives and do not have sulfonic acid groups or acrylamide groups as hydrophilic groups, such as polymer particles that are three-dimensionally cross-linked with acrylic acid polymers, are added to the grout material. Even in salt water from which ions such as calcium ions in the cement are eluted, there is almost no water absorption capability, so the particle size does not change, the interaction with the cement particles is relatively small, and thixotropic properties are not exhibited. On the other hand, when the cross-linked acrylic polymer particles containing sulfonic acid groups and / or acrylamide groups used in the present invention are added to the grout material, the water in the grout material is absorbed and the volume expands to several tens of times. As a result, they are present as relatively large particles in the liquid, and thixotropic properties are exhibited by the interaction with surrounding cement particles.

  The alkyl ether-modified cellulose resin used in the present invention is preferably hydroxyalkyl cellulose or hydroxyalkylalkyl cellulose in which a hydroxyalkyl group is introduced with respect to the hydroxyl group of the glucose ring of cellulose. Specific examples thereof include, for example, hydroxyethyl cellulose. (HEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), hydroxyethylmethylcellulose (HEMC), hydroxyethylethylcellulose (HEEC), hydroxybutylmethylcellulose (HBMC) and the like. Of these, hydroxyalkylalkylcellulose is particularly preferred. Examples of this product include Metrology 90SH-15000, hi90SH-15000 (HPMC) manufactured by Shin-Etsu Chemical Co., Ltd., Unishot A-10 (HPMC) manufactured by Daiichi Kogyo Seiyaku, and BERMOCOLL EBS-482FQ (HEEC) manufactured by Akzo Nobel. It is done.

  The crosslinked acrylic polymer particles used in the present invention are used in the range of 1/400 to 1/100 (weight ratio) with respect to the water in the grout material. If the amount used is within this range, a grout material having good underwater inseparability and high thixotropic properties can be obtained. If the amount used is less than 1/400, the obtained grout material has low inseparability in water, and may cause material separation and water pollution at the time of filling the cavity, and the resulting grout material has low thixotropy. Deviation from the gap cannot be sufficiently prevented. On the other hand, when the amount used exceeds 1/100, the viscosity of the resulting grout material becomes high and the fluidity is lowered, so that it becomes difficult to fill the cavity. It is preferable to use in the range of 1/300-1/150 (weight ratio) among the said ranges.

The underwater construction grout material of the present invention contains an alkyl ether-modified cellulose resin together with crosslinked acrylic polymer particles.
The alkyl ether-modified cellulose resin is used in the range of 1/1000 to 1/100 (weight ratio) with respect to the water of the grout material. If the amount used is within this range, a grout material having good underwater separability and high thixotropic properties can be obtained. When the amount used is less than 1/1000, the grout material obtained is not sufficiently separable in water, and may cause material separation and water pollution at the time of filling the cavity, and the effect of preventing breathing is not sufficient. When breathing occurs, voids are formed after filling the cavities due to volume shrinkage, and the strength as designed is not exhibited. In addition, when the amount used exceeds 1/100, the thixotropy of the obtained grout material is lowered, and it becomes difficult to prevent the grout material from deviating from the gap between the inner walls of the cavity after filling the cavity. It is preferable to use in the range of 1/500-1/200 (weight ratio) among the said range.

  The ratio of water and cement in the grout material for underwater construction according to the present invention is such that water / cement = 40/100 to 60/100 (weight ratio) in terms of excellent inseparability in water and filling into cavities. Use within the range. If the ratio is less than 40/100, the resulting grout material has high viscosity and low fluidity, so that it is difficult to fill the cavity. On the other hand, when the ratio exceeds 60/100, the viscosity of the grout material obtained is too low even when the crosslinked acrylic polymer particles containing sulfonic acid groups and / or acrylamide groups and the alkyl ether-modified cellulose resin are added. Underwater inseparability is not sufficient, and it tends to flow out by the flow of water. It is preferable to use in the range of 40 / 100-55 / 100 (weight ratio) among the said ranges.

In addition, the grout material for underwater construction of the present invention, in addition to the above-mentioned components, additives that are generally used mixed with cement, such as sand, earth, gravel, used as an aggregate, Inorganic powder such as clay, fly ash, bentonite, perlite, vermiculite, etc., calcium carbonate, fine powder silica, or inorganic or organic fiber such as wood flour, pulp, water-absorbing fiber, glass fiber, and / or Admixtures such as an antifoaming agent, a water reducing agent, an AE agent, and a foaming agent may be contained.
The grout material for underwater construction of the present invention can be used for filling cavities and gaps in contact with seawater such as marine structures such as revetment walls and harbor structures.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these. In the following, all parts and% are based on weight unless otherwise specified. In addition, the various characteristics of the grout material for underwater construction of the present invention were measured by the evaluation methods outlined below.

<Fluidity test>
The fluidity (flow value) of the grout material is measured by a method in accordance with Japanese Industrial Standard JIS R5201.
(Tool)
(1) Flow cone (metal flow cone defined in JIS R5201)
(2) Flow table (Flow table with a diameter of 30 cm as defined in JIS R5201)
(3) Stick (metal stick specified in JIS R5201)
(Test method)
(1) Place the flow cone on the flow table.
(2) The grout material is packed in a flow cone in two portions. Each layer is struck 15 times with a stick, and finally the surface is made up by compensating for the deficiency.
(3) Gently lift the cylinder in the vertical direction, 1 minute after the grout spreads, measure the diameter in the direction recognized as the maximum and the diameter in the direction perpendicular to it, and calculate the average value of these as the natural flow value. To do.
(4) A falling motion is given 15 times in 15 seconds, the diameter after the grouting material spreads is measured as the maximum diameter, and the diameter in the direction perpendicular thereto is measured, and the average value thereof is taken as the tapping flow value. .
(5) A value obtained by dividing the tapping flow value by the natural flow value is used as an index of thixotropy.

<Breathing test>
In accordance with Japan Society of Civil Engineers standard "Testing method for breathing rate and expansion rate of mortar of prepacked concrete (polyethylene bag method)" (JSCE-F 522-1999), material separation resistance (breathing rate) of grout material and The expansion coefficient was measured.
(Tool)
(1) Polyethylene bag (with a grout material in a diameter of about 50 mm and a length of 500 mm or more, polyethylene thickness of about 0.05 mm, bottom is square bottom)
(2) Measuring cylinder (capacity 1000ml)
(Test method)
(1) Fill a polyethylene bag with a grout material to a height of about 20 cm.
(2) Insert a polyethylene bag filled with a grout material into a graduated cylinder containing 400 ml of water so that air is not mixed gently.
(3) Lower the polyethylene bag until the water surface in the graduated cylinder and the surface of the grouting material coincide, and subtract 400 ml from the reading of the graduated cylinder to obtain the volume Vml of the grouting material.
(4) Tie the upper end of the polyethylene bag, hang it and let it stand.
(5) When 24 hours or more have passed after the start of measurement, read the water surface V ₁ ml by breathing and the surface V ₂ ml of the grout material in the same manner as (2) and (3), and subtract the latter from the former. Obtain the amount of water Bml by breathing. When there is no breathing water, V ₁ = V ₂ .
(6) The breathing rate and the expansion rate are calculated by the following equations.
B = V ₁ −V ₂
Breathing rate (%) = B / V × 100
Expansion rate (%) = (V ₁ −V) / V × 100

<Underwater inseparability test>
(Visual evaluation and test on turbidity (permeability) of water 60 minutes after sample input)
The underwater inseparability of the grout material is measured by a method in accordance with the Japan Road Public Corporation “Guide for Injecting Method of Back Cavity of Yaita Tunnel” (JHS313).
(Tool)
(1) 26 l of water is put in a water tank having a length of about 450 mm, a width of about 300 mm, and a height of about 300 mm. The water used is tap water having a pH of about 7-8.
(2) For turbidity, water is sampled with a spoid from a position 10 cm from the water surface, and the light transmittance at a wavelength of 800 nm is measured with a spectrophotometer.
(Test method)
(1) Pour the grout material into a flow cone having an inner diameter of 80 mm and a height of 80 mm (JHS standard).
(2) Place the flow cone in the water tank and quickly remove the flow cone. At this time, initial turbidity and the like are not generated as much as possible without giving an impact such as vibration.
(3) The turbidity (light transmittance) is measured before the injection material is put into the water tank and after 60 minutes. The light transmittance after 60 minutes is displayed in%.
(4) The turbidity of water after 60 minutes has been visually observed.

<Uniaxial compressive strength test>
(Equipment, test method)
In accordance with the Japan Society of Civil Engineers standard "Testing method for compressive strength of mortar or cement paste using a cylindrical specimen" (JSCE-G 505-1999), a cylindrical specimen having a diameter of 5 cm and a height of 10 cm is used. Measure strength characteristics (uniaxial compressive strength).

Synthesis example 1
After 750 g of cyclohexane and 10.0 g of sorbitan monostearate were charged into the reaction vessel, stirring was started. On the other hand, 207 g (32.5 mol%) of 2-acrylamido-2-methylpropanesulfonic acid was added to another container, and 0.02 g of hydroxy-tetramethyl-1-piperidineoxyl was contained while cooling from the outside, and sodium hydroxide 24 4.0 g of sodium hydroxide solution in which 0.0 g was dissolved was added dropwise to neutralize 60 mol% of 2-acrylamido-2-methylpropanesulfonic acid, and then 142 g of acrylamide (67.3 mol%) and 0.5 g of acrylic acid ( 0.2 mol%), 0.15 g of N, N′-methylenebisacrylamide and 0.5 g of ammonium persulfate were added and dissolved.
Next, the monomer aqueous solution containing the polymerization initiator and the crosslinking agent obtained as described above is added to the above cyclohexane, 0.3 g of sodium hydrogen sulfite is added, and then the temperature is raised to 70 ° C. This initiated the polymerization. After the exotherm due to polymerization had subsided, 3.0 g of a surfactant (sucrose stearate) was added, and the mixture was stirred at 60 ° C. to 70 ° C. for 1 hour. After 330 g of water was extracted by azeotropic dehydration, the resin was taken out and dried at 70 ° C. under reduced pressure to obtain polymer particles A.

Synthesis example 2
A pressure reactor was charged with 100 parts by weight of pulp and 50 parts by weight of dimethyl ether, and at 90 ° C. or less, 230 parts by weight of 50% by weight aqueous sodium hydroxide solution was added dropwise with stirring to prepare alkali cellulose. Next, the reaction solution was cooled to 40 ° C. or lower, charged with 150 parts by weight of chloromethyl and 45 parts by weight of propylene oxide, and reacted at 40 to 90 ° C. for 3 hours. The obtained reaction product was washed with hot water at 80 to 90 ° C., and then air-dried at 80 ° C. to obtain 125 parts by weight of colorless solid hydroxypropylmethylcellulose (hereinafter referred to as HPMC).

Example 1
Into a stirring vessel (KITCHEN AID KSM5), 1620 parts of water was added, and 3600 parts of cement was added while stirring, followed by stirring for 2 minutes. Subsequently, 180 parts of water, 10 parts of polymer particles A and 5 parts of HPMC were mixed in advance, and stirred for 1 minute to obtain a grout material for underwater construction according to the present invention.

Example 2
1782 parts of water was placed in a stirring vessel, and 3600 parts of ordinary Portland cement (manufactured by Taiheiyo Cement) was added while stirring, followed by stirring for 2 minutes. Next, 198 parts of water, 9.9 parts of polymer particles A and 4.95 parts of HPMC were added in advance, and stirred for 1 minute to obtain a grout material for underwater construction of the present invention.
Example 3
A grout material for underwater construction according to the present invention was obtained in the same manner as in Example 1 except that the amount of the polymer particles A was changed to 6.67 parts.

Example 4
A grout material for underwater construction of the present invention was obtained in the same manner as in Example 2 except that the amount of the polymer particles A was changed to 6.6 parts and the amount of HPMC was changed to 6.6 parts.
Example 5
1458 parts of water is placed in a stirring vessel, and 3600 parts of ordinary Portland cement (manufactured by Taiheiyo Cement) is added while stirring, and stirred for 2 minutes. Then, 162 parts of water, 5.4 parts of polymer particles A, and 3.24 parts of HPMC were mixed in advance and stirred for 1 minute to obtain a grout material for underwater construction according to the present invention.

Comparative Example 1
A grout material was obtained in the same manner as in Example 1 except that the polymer particles A were not added.
Comparative Example 2
A grout material was obtained in the same manner as in Example 4 except that HPMC was not added.
Comparative Example 3
A grout material of the present invention was obtained in the same manner as in Example 4 except that the amount of the polymer particles A was changed to 3.96 parts.
Comparative Example 4
2025 parts of water was placed in a stirring vessel, and 3600 parts of ordinary Portland cement (manufactured by Taiheiyo Cement) was added while stirring, followed by stirring for 2 minutes. Next, a mixture of 225 parts of water, 11.25 parts of polymer particles A and 5.63 parts of HPMC was added and stirred for 1 minute to obtain a grout material.

「水／Ｃ」はセメントに対する水の配合比率、「Ａ／水」は水に対する架橋アクリル系高分子粒子の配合比率、「ＨＰＭＣ／水」は水に対するＨＰＭＣの配合比率を意味する。

“Water / C” means the mixing ratio of water to cement, “A / water” means the mixing ratio of crosslinked acrylic polymer particles to water, and “HPMC / water” means the mixing ratio of HPMC to water.

「水／Ｃ」はセメントに対する水の配合比率、「Ａ／水」は水に対する架橋アクリル系高分子粒子の配合比率、「ＨＰＭＣ／水」は水に対するＨＰＭＣの配合比率を意味する。

“Water / C” means the mixing ratio of water to cement, “A / water” means the mixing ratio of crosslinked acrylic polymer particles to water, and “HPMC / water” means the mixing ratio of HPMC to water.

Examples 1 to 5 all have high water inseparability and high thixotropic properties.
Since all of Comparative Examples 1 to 4 are inferior in water inseparability, there is a risk that material separation or water pollution may occur during filling into the cavity. Since Comparative Examples 1 and 3 have low thixotropy, deviation from the gap is likely to occur after injection into the cavity. In Comparative Examples 1 and 2, since breathing and volume shrinkage are large and voids are formed after curing, the strength as designed cannot be expressed.

Claims (2)

  A grout material for underwater construction comprising at least cement, water, crosslinked acrylic polymer particles and an alkyl ether-modified cellulose resin, wherein the weight ratio of water to the cement is 40/100 to 60/100, The weight ratio of the cross-linked acrylic polymer particles is 1/400 to 1/100, and the weight ratio of the alkyl ether-modified cellulose resin to the water is 1/1000 to 1/100. Construction grout material. The grout material for underwater construction according to claim 1, wherein the crosslinked acrylic polymer particles contain a sulfonic acid group and / or an acrylamide group.