JP5936949B2 - Underwater inseparable concrete - Google Patents

Description

It relates to underwater non-separable concrete.

  Conventionally, various thickeners such as cellulose ether, polyacrylamide, polyethylene oxide, and gums have been used for water-inseparable concrete so that cement components are not dispersed and dissolved in water.

JP-A-6-206753 Japanese Patent Laid-Open No. 7-232949 Japanese Patent Laid-Open No. 9-268045 JP-A-9-208287 JP-A-7-267715 International Publication No. 2010/047408 Pamphlet

  These thickeners prevent the cement from separating and dispersing in water by giving viscosity to water in concrete and adhering solids to each other. However, if the adhesiveness is too strong, the workability is deteriorated, or the setting delay is easily caused by the added amount. Also, in recent years, there are many construction methods that finally change from underwater curing conditions to dry curing conditions, such as placing primary lining concrete such as tunnels under spring and underground structures.

  Therefore, in the case of construction, there is a demand for underwater non-separable concrete having a good workability with ensured underwater inseparability, a small setting delay, and a small shrinkage.

  1 selected from the group consisting of hydroxyalkylcellulose and hydroxyalkylalkylcellulose as a concrete composition containing cement binder, aggregate and water reducing agent as an underwater inseparable concrete composition for underwater construction using an antifoaming agent The thing which added the acetylene glycol derivative as a seed | species or 2 or more types of water-soluble cellulose ether and an antifoamer is proposed (refer patent document 1).

  As an embankment material for underwater placement, an underwater embankment material is proposed which is made by mixing and kneading a hydraulic powder material such as cement, granulated / powdered slag, thickener and water (patent document). 2). Patent Document 2 discloses that, as a thickener, nonionic cellulose ether alone or in combination with a group consisting of polyacrylamide, polyethylene oxide, gums and the like is preferable, a hydraulic powder material, water granulation and / or wind. An underwater embankment material characterized by blending and kneading crushed slag, thickener and / or bentonite with water is described.

  Water-soluble materials such as cement and other non-ionic cellulose ethers such as hydroxypropylmethylcellulose and water-soluble polysaccharides such as welan gum, water-soluble acrylic derivatives such as polyacrylamide, and hydroxypropylated starch A flowable composition for non-cutting method characterized in that at least one substance selected from starch derivatives is an essential component, and the ratio of water-soluble cellulose ether to aggregating substance is 99: 1 to 20:80. Has been proposed (see Patent Document 3).

  Cement mortar composition characterized by adding 0.02 to 3 parts by weight of nonionic water-soluble cellulose ether and 0.001 to 1 part by weight of water-soluble polysaccharide to 100 parts by weight of cement The thing is proposed (refer patent document 4).

  (A) a high-performance water reducing agent, a high-performance AE water-reducing agent admixture; (B), a swellable, low-substituted hydroxypropyl cellulose that is not completely soluble in water; and ( C) Concrete obtained by adding an admixture containing each component of a nonionic water-soluble cellulose ether has been proposed (see Patent Document 5).

  Patent Document 6 describes cellulose ether, detan gum, acrylamide, and bentonite.

However, Patent Documents 1 to 6 do not have a description of using an expansion material.

As a result of intensive studies, the present inventor mainly comprises a specific swelling material, a shrinkage reducing agent, a thickener containing cellulose ether detan gum, polyacrylamide, bentonite, and polycarboxylic acid. Water containing a water reducing agent, a water reducing agent mainly composed of melamine sulfonic acid, admixtures such as fine limestone powder and / or fly ash, fine aggregate, coarse aggregate, water, and early strong cement By using non-separable concrete, the inventors have obtained the knowledge that the above problems can be solved, and have completed the present invention.

That is, the present invention mainly comprises free lime, an expansion material mainly containing anhydrous gypsum, a shrinkage reducing agent, a thickener containing cellulose ether, detan gum, polyacrylamide, bentonite, and polycarboxylic acid. Containing water reducing agent, water reducing agent mainly composed of melamine sulfonic acid, admixture containing fine limestone powder and / or fly ash, fine aggregate, coarse aggregate, water, and early strong cement Ri greens and, in the thickener, the proportion of the cellulose ether is from 5.3 to 82.0%, the proportion of Deyutangamu is 1.0 to 12.6%, the proportion of polyacrylamide 0.1 to 2.1 %, Bentonite ratio is 7.5 to 80.0% underwater non-separable concrete.

  By using the underwater non-separable concrete of the present invention, the initial age strength is obtained, and in the construction, in addition to the underwater non-separability, the workability of the concrete is good, and a high-flowing concrete with a small shrinkage is provided. Is possible.

The present invention will be described in detail below.
Parts and% used in the present invention are based on mass unless otherwise specified.

The expansion material used in the present invention is composed of a mineral mainly composed of free lime and anhydrous gypsum produced by heat-treating a mixture containing a CaO raw material and a CaSO ₄ raw material, and the proportion in the mineral is anhydrous gypsum. Is preferably 10-50 parts in total of 100 parts of free lime and anhydrous gypsum, and more preferably 20-40 parts. When the anhydrous gypsum is less than 10 parts, for example, it exhibits rapid expansibility by the age of one day, and cracks may occur in the hardened cement body using the expansive material, or strength development may be reduced. If the amount of gypsum exceeds 50 parts, the expansion performance tends to decrease.

When producing the expandable material of the present invention, it is desirable to heat the blend containing CaO raw material and CaSO ₄ raw material, synthesize clinker mainly composed of free lime and anhydrous gypsum and pulverize it to produce . It is also possible to synthesize free lime and anhydrous gypsum separately and mix them to synthesize the same composition as the expansion material of the present invention, but the effect of the present invention, that is, excellent expansion From the viewpoint of obtaining performance, it is preferable to produce a clinker mainly composed of free lime and anhydrous gypsum by heat-treating a mixture containing a CaO raw material and a CaSO ₄ raw material, and then pulverizing it.

As a method of confirming whether or not it was manufactured by heat-treating a mixture of CaO raw material and CaSO ₄ raw material, synthesizing clinker mainly composed of free lime and anhydrous gypsum, and pulverizing this. For example, the coarse particles of the expansion material, specifically, particles larger than 100 μm are observed with a microscope or the like, and composition analysis is performed, and it is easy to confirm that free lime and anhydrous gypsum are mixed in the particles. Can be determined.

Although it is the heat processing temperature at the time of manufacturing the expansion | swelling material of this invention, the range of 1100-1600 degreeC is preferable and the range of 1200-1500 degreeC is more preferable. If it is less than 1100 degreeC, the expansion performance of the obtained cement admixture is not enough, and if it exceeds 1600 degreeC, an anhydrous gypsum may decompose | disassemble. The mixing method of the raw materials is not particularly limited, and a normal method is possible. It does not specifically limit as the heat processing method which manufactures an expandable material, It can carry out by using a rotary kiln, an electric furnace, etc.

Examples of the CaO raw material include limestone and slaked lime, and examples of the CaSO ₄ raw material include dihydrate gypsum, hemihydrate gypsum, and anhydrous gypsum. Impurities such as SiO ₂ , Fe ₂ O ₃ , CaF ₂ , MgO, and TiO ₂ present in the raw material are not particularly problematic as long as the object of the present invention is not substantially inhibited.

Although the particle size of the expansion material of the present invention is not particularly limited, it is usually preferably from 1500 to 9000 cm ² / g, more preferably from 2500 to 4000 cm ² / g in terms of the specific surface area of branes. If the particle size of the expansion material is less than 1500 cm ² / g, the long-term durability may deteriorate, and if it exceeds 9000 cm ² / g, sufficient expansion performance may not be obtained.
The amount of the expansion material used is preferably 1 to 10 parts, more preferably 2 to 8 parts, with respect to 100 parts of the early strong cement. If the amount is less than 1 part, sufficient expansion performance may not be obtained. If the amount exceeds 10 parts, slump down due to the elapsed time becomes remarkable, and workability may deteriorate or abnormal expansion may occur.

  The cellulose ether used in the present invention is hydroxyalkyl cellulose and / or hydroxyalkylalkyl cellulose. Examples of the hydroxyalkyl cellulose include hydroxyethyl cellulose and hydroxypropyl cellulose, and examples of the hydroxyalkyl alkyl cellulose include hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl ethyl cellulose, which are used alone or in combination of two or more. Of these, hydroxypropylmethylcellulose is particularly preferred.

  The viscosity of the cellulose ether is preferably 5,000 to 50,000 mPa · s, preferably 8,000 to 25,000 mPas, in the viscosity of a 1% aqueous solution measured using a B-type viscometer at 20 ° C. and 10 rpm. -S is more preferable. The moisture content of the powder is preferably 15% or less.

  The proportion of cellulose ether in the thickener is preferably 30 to 75%, more preferably 35 to 70%. If it is less than 30%, it may be difficult to obtain inseparability in water, and if it exceeds 70%, workability may be deteriorated.

  Cellulose ether generally has air entrainment properties, so when there is a large amount of air in the concrete and the strength may be reduced, it is desirable to control the amount of air to a predetermined level with an antifoaming agent.

  The detan gum used in the present invention is a natural high-molecular polysaccharide having two glucose, one glucuronic acid, and three rhamnose as structural units.

  The viscosity of the dutan gum is preferably 2800 mPa · s or more, more preferably 3000 to 5500 mPa · s in the viscosity of a 0.25% aqueous solution measured using a B-type viscometer at 20 ° C. and 10 rpm.

  The ratio of detan gum in the thickener is preferably 3 to 40%, more preferably 5 to 35%. If it is less than 3%, it may be difficult to obtain inseparability in water, and if it exceeds 40%, workability may be deteriorated.

  The polyacrylamide used in the present invention contains a highly reactive acid amide group in the polymer. Of these, methacrylic cationic polymers are preferred. The viscosity of the polyacrylamide is preferably 40 to 80 mPa · s, more preferably 50 to 70 mPa · s, in the viscosity of a 0.2% aqueous solution measured using a B-type viscometer at 20 ° C. and 10 rpm.

  The proportion of polyacrylamide in the thickener is preferably 0.2 to 5%, more preferably 0.5 to 3%. If it is less than 0.2%, it may be difficult to obtain retainability in water, and if it exceeds 5%, workability may be deteriorated.

  The bentonite used in the present invention is a kind of clay mineral and mainly contains montmorillonite. Examples of bentonite include calcium bentonite, sodium bentonite, and potassium bentonite.

  The swelling degree of bentonite is preferably 20 ml / 2 g or more. The water content of bentonite is preferably 10% or less. The particle size of bentonite is preferably 90% or more through 80 mesh.

  The proportion of bentonite in the thickener is preferably 5 to 25%, more preferably 8 to 23%. If it is less than 5%, dispersion during kneading may be difficult to obtain, and if it exceeds 25%, the inseparability in water may be deteriorated.

0.1-3 kg / m < ³ > is preferable and the usage-amount of a thickener has more preferable 0.2-2 kg / m < ³ >. If it is less than 0.1 kg / m ³ , the inseparability in water may deteriorate, and if it exceeds ³ kg / m ³ , workability may deteriorate.

  As the water reducing agent of the present invention, two kinds of water reducing agents mainly composed of polycarboxylic acid and water reducing agents mainly composed of melamine sulfonic acid are used. If these two types are not used, there is no good fluidity and flow retention, and predetermined physical properties cannot be obtained. While the two types are blended, other water reducing agents can be used in combination depending on construction conditions such as temperature conditions and further fluidity.

  Examples of the water reducing agent mainly composed of the polycarboxylic acid of the present invention include those containing polycarboxylic acid or a salt thereof as an active ingredient.

  The water reducing agent mainly composed of melamine sulfonic acid according to the present invention includes a melamine sulfonic acid-based condensate as an active ingredient, a melamine sulfonic acid-based compound as an active ingredient, a melamine sulfonic acid-based compound and a polyol complex. Those with active ingredients, those with methylol melamine condensates as active ingredients, those with modified methylol melamine condensates as active ingredients, those with modified methylol melamine condensates and carboxylic acid compounds as active ingredients, high sulfonated melamine What uses a condensate salt as an active ingredient is mentioned.

  As the other water reducing agent, any water reducing agent, high performance water reducing agent, high performance AE water reducing agent, dispersant, and fluidizing agent that can be used for mortar and concrete can be used. Examples of such a water reducing agent component include, for example, a naphthalene sulfonic acid formalin high condensate salt as an active ingredient, a naphthalene sulfonic acid soda formalin condensate as an active ingredient, naphthalene sulfonic acid sodium salt formalin polycondensation. Those having a product as an active ingredient, those having a highly condensed aromatic sulfonic acid as an active ingredient, those having a modified lignin and highly condensed aromatic sulfonic acid complex as an active ingredient, those having an alkylallyl sulfonic acid as an active ingredient, Effective with alkyl allyl sulfonate, active component with alkyl allyl sulfonic acid high condensate, effective with alkyl allyl sulfonate high condensate, effective with alkyl naphthalene sulfonic acid formalin condensate Ingredients, Naphthalenesulfonic acid modified lignin condensate as active ingredient Those containing naphthalenesulfonic acid-modified lignin condensate and lignin as active ingredients, those containing a modified lignin, alkylallylsulfonic acid and active sustained polymer composite as active ingredients, polyalkylsulfonic acid and reactive polymer Active ingredients, alkylallyl sulfonic acid high condensate and carboxyl group-containing polyvalent polymer as active ingredients, alkyl allyl sulfonate modified lignin co-condensate and modified lignin as active ingredients, lignin derivatives Those containing alkyl allyl sulfonate as an active ingredient, those containing polyalkyl allyl sulfone surfactant as an active ingredient, those containing alkyl allyl sulfonic acid formalin condensate as an active ingredient, polyalkyl allyl sulfonic acid compounds as active ingredients Can be mentioned, and any of these Well, it may be used in combination of two or more. The use of a water reducing agent can increase the dispersibility of each component contained at a low water ratio, but if the dispersibility is increased too much, the amount of suspended solids increases from the viewpoint of underwater non-separable concrete, and the underwater non-separation performance. Therefore, it is necessary to adjust the amount of suspended solids within the range of 100 mg / l or less.

The amount of water reducing agent used is preferably 0.1 to 20 kg / m ³ , more preferably 0.2 to 10 kg / m ^{3 in} terms of solid content per 1 m ^{3 of} concrete.
The water reducing agent is used as a powder or liquid. In the case of liquid, it is used as a solution mixed with water. When used as a liquid, the solid content concentration of the water reducing agent is preferably 3 to 70%, more preferably 10 to 50%.

In the underwater non-separable concrete of the present invention, it is possible to use a retarder for the purpose of further extending the construction time. As the type of the retarder, oxycarboxylic acids such as citric acid, gluconic acid, tartaric acid, malic acid, and salts thereof can be used.

As the early strong cement used in the present invention, a commercially available early strong Portland cement is used.
The amount of early-strength cement used is not particularly limited, but is preferably 350 kg / m ³ or more, more preferably 400 kg / m ³ or more during concrete mixing.

The shrinkage reducing agent used in the present invention, for example, suppresses the drying shrinkage of the sprayed mortar after curing and suppresses the occurrence of cracks. As a shrinkage reducing agent, RO (AO) nH (where R is an alkyl group having 4 to 6 carbon atoms, A is one or more alkylene groups having 2 to 3 carbon atoms, and n is an integer of 1 to 10) Or a general formula X {O (AO) nR} m (where X is a residue of a compound having 2 to 8 hydrogen groups, and AO is carbon. An oxyalkylene group having 2 to 18 carbon atoms, R is a hydrogen atom, a hydrocarbon group having 1 to 18 carbon atoms, or an acyl group having 2 to 18 carbon atoms, n is 30 to 1000, and m is 2 to 8). The polyoxyalkylene derivative etc. whose 60 mol% or more of the oxyalkylene group is an oxyethylene group are mentioned. In these, a polyoxyalkylene derivative is preferable at the point with a big effect.
The amount of the shrinkage reducing agent is not particularly limited, but is preferably used in 3~35kg / ^{m 3} cement concrete during compounding, 5~30kg / ^{m 3} and more preferably.

The typical example of the concrete mixing | blending of this invention is shown.
・ Cement 350-600kg / m ³
Aggregate 1650-1900 kg / m ³
・ Water 160-210kg / m ³

The underwater non-separable concrete of the present invention is blended with limestone fine powder, fly ash, limestone fine powder and fly ash (hereinafter referred to as admixture). The reason is to prevent the amount of suspended matter and pH as much as possible and to suppress the heat of hydration under the assumption of under spring water or running water.
The amount of the admixture used is preferably 50 kg / m ³ or more, more preferably 100 kg / m ³ or more during the concrete compounding.

  The aggregates of the present invention such as fine aggregate and coarse aggregate are preferably those having a low water absorption rate and high aggregate strength. The aggregate is not particularly limited as long as it can be sprayed. However, river sand, mountain sand, sea sand, lime sand, silica sand, etc. can be used as fine aggregate, and river gravel as coarse aggregate. Mountain gravel, lime gravel, etc. can be used, and crushed sand and crushed stone can also be used.

  The cement composition of the present invention can be produced according to an ordinary method. For example, a thickener, a water reducing agent, an expansion material, and a shrinkage reducing agent are added to cement, aggregate, and water in a raw plant or an installation site. It is prepared by adding and stirring and mixing. The water reducing agent can be used as a so-called post-addition agent, which is added to the kneaded water first or added to the kneaded concrete. Moreover, the method of preparing mortar first and using a coarse aggregate after that can also be used.

  The water cement ratio of the cement composition of the present invention is preferably 25 to 60%, more preferably 30 to 50%.

  The fine aggregate ratio of the cement composition of the present invention is preferably 20% or more, more preferably 30 to 70% in volume ratio.

  In the present invention, a thickener in which cellulose ether, detan gum, polyacrylamide, bentonite, and the like are uniformly mixed in advance is added to water and other compositions and kneaded, so that rapid water absorption is eliminated. This generation is eliminated, the thickening effect is exhibited, and the cement composition of the present invention is completed. When bentonite is not added in advance, water is rapidly absorbed and a so-called stagnation state is obtained, and the thickening mechanism may not be sufficiently exhibited.

"Experiment 1"
Hereinafter, specific embodiments of the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
Experiments were performed at 20 ° C. unless otherwise specified. Concrete formulation, coarse aggregate maximum dimension 13 mm, a fine aggregate ratio (s / a) 44%, fine aggregate 685kg / ^{m 3,} coarse aggregate 888kg / ^{m 3,} cement 500 kg / ^{m 3,} water 195 kg / m ³ (water cement ratio: 39%), limestone fine powder 140 kg / m ³ , expansion material 20 kg / m ³ , shrinkage reducing agent 10 kg / m ³ , water reducing agent a is 4 kg / m ^{3 in} terms of solid content, water reducing agent i is The solid content was 4 kg / m ³ , and 1 kg / m ^{3 of the} thickener shown in Table 1 was used.
For the kneading, a 55 L biaxial mixer was used. Cement, limestone fine powder of admixture, fine aggregate, water, dispersant, retention agent, thickener, shrinkage reducing agent, expansion agent are mixed and kneaded for 3 minutes, then coarse aggregate is added for 30 seconds. Concrete was prepared by mixing. The concrete was measured for slump flow (fluidity), 50 cm arrival time, suspended solid amount, compressive strength, pH, and compressive strength obtained from water, and the results are shown in Table 2. In each example, the materials used and the measurement methods are as follows.

<Materials used>
Fine aggregate: Himekawa sand (water absorption rate: 1.94%, density: 2.62, FM: 2.80)
Coarse aggregate: crushed stone 5mm-13mm (water absorption rate: 1.0%, density: 2.67, FM: 6.10)
Cement: Hayashi Portland Cement (Density: 3.12, manufactured by Denki Kagaku Kogyo)
Thickener:
Cellulose ether (Ms in the table): Hydroxypropyl methylcellulose, 1% aqueous solution viscosity 20,000 mPa · s (10 rpm), manufactured by Shin-Etsu Chemical Co., Ltd. % Aqueous solution viscosity 4,350 mPa · s (10 rpm), C.I. P. Kelco, commercial product, polyacrylamide (denoted as Pa in the table): 0.2% aqueous solution viscosity 63 mPa · s (10 rpm), Nippon Kasei Co., Ltd., commercial product, bentonite (denoted as Bn in the table): US commercial product potassium Bentonite, swelling degree 27.0 ml / 2 g, moisture content 8.9%, particle size wet residue 45 μm 5.0%, loss on ignition 7.0%, density 2.5 g / cm ³
Admixture: Limestone fine powder, density: 2.68, 100 mesh product, water-reducing agent, Joetsu Mining Co., Ltd .: polycarboxylic acid-based water reducing agent, liquid, solid content concentration 40%, commercial product water-reducing agent A: melamine sulfonic acid-based formalin Condensate, liquid, solid content concentration 40%, commercial product expansion material α: heat-treating compound containing CaO raw material and CaSO ₄ raw material, synthesize clinker mainly composed of free lime and anhydrous gypsum and pulverize this An expanded material mainly composed of free lime and gypsum (30 parts of anhydrous gypsum in a total of 100 parts of free lime and anhydrous gypsum), Blaine specific surface area 3500 cm ² / g
Shrinkage reducing agent Α: Low molecular weight alkylene oxide copolymer, commercial product

<Measurement method>
Slump flow (fluidity): Conforms to “JIS A1150 slump flow”.
50 cm arrival time: Conforms to “JIS A1150 Slump Flow”.
pH: Compliant with JSCE-D104, Appendix 2 “Standards for the quality of non-separable admixture in water for concrete” (draft).
Suspension amount (amount of suspended solids): Conforms to JSCE-D104, Annex 2 of the Japan Society of Civil Engineers Standard: Quality Standards for Water Inseparable Admixtures for Concrete (Draft).
Compressive strength: Conforms to “JIS A1108 Concrete Compressive Strength Test Method”. The age of the compressed material was material age 24H.
Compressive strength of underwater sampling: “JSTCE-F 504 standard”: “How to make an underwater preparation specimen for compressive strength test of underwater inseparable concrete”. Measure the compressive strength of underwater specimens with a material age of 24H.

  From the results shown in Table 2, it was confirmed that when one of the constituent materials of the thickener became 0 parts, the arrival time of 50 cm increased or decreased, the amount of suspended substances increased, and the pH value increased. In addition, the compressive strength due to underwater sampling was significantly reduced. For this reason, the constituent material of the thickener is cellulose ether, detan gum, polyacrylamide, and bentonite as essential components.

"Experimental example 2"
The amount of expansion material, shrinkage reducing agent and coarse aggregate, fine aggregate, cement, water, fine powder of limestone, dispersant, water reducing agent a, water reducing agent a (mixed with Experiment No. 1-1) shown in Table 3 were tested. The same formulation as in Example 1 was used, and the same test and expansion amount as in Experimental Example 1 were measured. The results are shown in Table 4.

  From the results shown in Table 4, when the expansion material and the shrinkage reducing agent were not mixed, shrinkage was observed at the age of 7 days, and further shrinkage was confirmed at the age of 28 days. In the case of no contamination, the flow value immediately after kneading was low, the time for reaching 50 cm was long, and the amount of suspended solids increased. When only the expansion material was added, the amount of expansion at the 7th day was small, the time to reach 50 cm was early, and the pH was increased. When only the shrinkage reducing agent was added, it contributed to the shrinkage side at the age of 7 days, and significantly contracted at the age of 28 days. In addition, the arrival time of 50 cm was early, the amount of suspended solids increased, and the compressive strength at the time of underwater sampling decreased. Therefore, in the present invention, it is essential that the expansion material and the shrinkage reducing agent are blended.

"Experiment 3"
Using the formulation of experiment No. 1-1, using the type of expansion material and shrinkage reducing agents shown in Table 5, the expansion member 20 kg / m ^3, Experiment 2 was used in an amount of shrinkage reducing agent 10 kg / m ³ The same test was conducted. The results are shown in Table 5.

<Materials used>
Expansion material β: Calcium sulfoaluminate-based expansion material, Blaine specific surface area 3500 cm ² / g, commercial product expansion material γ: Quick lime-based expansion material, Blaine specific surface area 3500 cm ² / g, commercial product shrinkage reducing agent Β: Commercial product, Glycol ether / amino alcohol derivative shrinkage reducing agent Γ: commercial product, alkylene oxide adduct system of lower alcohol

From the results of Table 5, when the expanded material β was used, the amount of expansion at the age of 7 days was small regardless of the type of shrinkage reducing agent, and the contraction was remarkably confirmed at the material age of 28 days. In addition, when the expandable material γ is used, regardless of the type of shrinkage reducing agent, the slump is significantly reduced, the amount of suspended solids is large, the pH is high, and the shrinkage is remarkably confirmed at the age of 28 days. It was done. In the case of the expansion material α, the shrinkage reducing agent has little influence and the expansion amount is stable. For this reason, the expansion material is preferably a free lime / gypsum system.

"Experimental example 4"
About the kind of water reducing agent shown in Table 6, the quantity shown to Experimental example 1 was added and concrete was adjusted, and the slump flow of the concrete accompanying the elapsed time from concrete kneading was measured. The results are shown in Table 6.
Concrete slump flow: Elapsed time 0 hours, 2 hours, 4 hours, 6 hours, and 8 hours.

<Materials used>
Water reducing agent u: Mainly composed of naphthalenesulfonic acid formalin condensate, commercial product, liquid, solid content concentration 40%
Water reducing agent D: Mainly based on lignin sulfonate, commercially available product, liquid, solid concentration 40%
Water-reducing agent O: Mainly based on aminosulfonic acid, commercial product, liquid, solid content 40%
Water reducing agent: Mainly based on polycarboxylic acid, commercially available, Powder water reducing agent Key: Mainly based on melamine sulfonic acid formalin condensate, commercially available, powder

As shown in Table 6, when one type of water reducing agent was used, the concrete caused a remarkable flow down in 2 hours or 4 hours in all cases of the water reducing agent. Only when a polycarboxylic acid liquid or powder or melamine sulfonic acid liquid or powder is used, even if the slump flow tends to be 4 hours or more, no flow down occurs. Further, when a water reducing agent is further added to two types of polycarboxylic acid and melamine sulfonic acid, the properties are the same as when two types are used. In other combinations, the slump flow was significantly reduced.
Therefore, two or more types of water reducing agents, polycarboxylic acid and melamine sulfonic acid, are required.

“Experimental Example 5”
Using the same concrete material as in Experimental Example 1, concrete was prepared from the concrete composition shown in Table 7, and the same test as in Experimental Example 2 was performed. The results are shown in Table 8.

<Materials used>
Fly ash: JIS type II product, density 2.40 g / cm ³ , commercial product, manufactured by Tohoku Electric Power Industry Co., Ltd.

  According to Table 8, when the limestone fine powder of Experiment No. 1-1 was changed to fly ash, there was no particular change in physical properties, but when limestone fine powder and fly ash were not added, the amount of suspended solids increased. The pH value also increases. For this reason, it is necessary to mix limestone fine powder and fly ash with the concrete of the present invention.

"Experimental example 6"
Concrete was prepared using a cement-type concrete blend described in Table 9, and the same test as in Experimental Example 2 was performed. The results are shown in Table 10.

<Materials used>
Ordinary cement: Ordinary Portland cement, commercially available, density 3.15 g / cm ³

  From the results in Table 10, compared to Experiment No. 1-1 using early-strength cement, when ordinary cement was used, slump flow decreased significantly after 4 hours, and the amount of suspended matter and pH were also higher. The compression strength was also low. For this reason, the cement is preferably an early strong cement.

"Experimental example 7"
Tests similar to those of Experimental Example 2 were performed using an expanding material mainly composed of free lime and anhydrous gypsum in the blending ratio shown in Table 11. The results are shown in Table 12.

  From the results in Table 12, when the amount of gypsum in the expanded material increases, the amount of expansion at the age of 7 days decreases, and when the amount of anhydrous gypsum exceeds 55 parts, the value is almost the same as when there is no shrinkage reducing agent. It was. Also, when the amount of gypsum in the expanded material decreases, the amount of expansion with age increases, and when the amount of anhydrous gypsum becomes 0 parts, the amount of expansion increases significantly, and the slump flow value with elapsed time decreases, The amount of suspended matter increases and the pH also increases.

The underwater non-separable concrete of the present invention has fluidity and retention as compared with conventional underwater inseparable concrete, has good underwater inseparability, has high initial strength, and has a small shrinkage. I can do it.

Claims (3)

Expansion agent mainly composed of free lime and anhydrous gypsum, shrinkage reducing agent, thickener containing cellulose ether, detan gum, polyacrylamide, bentonite, water reducing agent mainly composed of polycarboxylic acid, melamine sulfone a water reducing agent mainly containing acid, and admixture comprising a limestone fine powder and / or fly ash, and fine aggregate, and coarse aggregate, and water, Ri greens contain early strength cement, increasing In the adhesive, the proportion of cellulose ether is 5.3 to 82.0%, the proportion of detan gum is 1.0 to 12.6%, the proportion of polyacrylamide is 0.1 to 2.1%, and the proportion of bentonite is Underwater non-separation concrete which is 7.5 to 80.0% . 2. The underwater non-separable concrete according to claim 1, wherein the expanded material mainly composed of free lime and anhydrous gypsum is 10 to 50 parts in total 100 parts of anhydrous lime and anhydrous gypsum. The thickener in which cellulose ether, detan gum, polyacrylamide, and bentonite are previously powdered uniformly is added to water and other compositions and kneaded, according to claim 1 or 2 . A method for producing underwater non-separable concrete.