JPH1160312A - Production of cement composition for centrifugal forming and centrifugal formed body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To largely decrease the amt. of whitewash discharged without decreasing the slump of a cement compsn. and the strength of a concrete or mortar by kneading a (high-performance) water reducing agent (component A), cement, water and fine aggregate (or coarse aggregate), adding a thickener (component B), kneading, and specifying the yielding point and the plastic viscosity of the cement compsn. SOLUTION: This cement compsn. shows a yielding point of 0.85 to 1.15 times, that of a standard cement compsn. and a plastic viscosity of 1.5 to 5.0 times that of the standard cement compsn. The standard cement compsn. means a compsn. excluding the component (B) from the above cement compsn. and having the same compounding ration and the same water reducing rate as the objective compsn. except for the components (A) and (B). The weight average mol.wt. of the component (B) (e.g. an acrylic acid water-soluble polymer) is 5000 to 5000000. The first kneading time and the second kneading time are controlled to 1 to 300 sec and 10 to 300 sec, respectively. The compounding ratios are controlled to (A)/cement =0.001 to 0.012, water/cement =0.25 to 0.45, and 120 to 180 kg of water per 1 m<3> of concrete or mortar.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal molding cement composition suitable for the production of concrete products and mortar products such as concrete piles, poles, steel pipe composite piles, fume pipes, steel pipe linings, etc. The present invention relates to a method for producing a product, and a molded product obtained by centrifugally molding a cement composition produced by the production method.

[0002]

2. Description of the Related Art Conventionally, concrete piles and poles,
Concrete products such as fume pipes are manufactured by molding and compacting by centrifugal force (hereinafter, these products are collectively referred to as centrifugal molded products). In the centrifugal force forming step, the water in the concrete is squeezed out to form a dense structure, but this water contains cement and fine powder in the aggregate, and is discharged as so-called glue. That is, slag is a water slurry containing cement as a main component.

[0003] Particularly, in piles and the like that require high strength, a large amount of a high-performance water reducing agent is added, so that the amount of slag is large.
Moreover, the mortar layer on the inner surface of the pipe becomes less tight. This slag is strongly alkaline, so after settling and neutralization,
Solids must be disposed of as industrial waste. For this reason, not only is a large amount of cost required, but also recently it has become difficult to secure a waste disposal site, which has become a major problem for the centrifugal molding industry.

For this reason, a method has been disclosed in which noro is reused as a raw material for concrete products (Japanese Patent Laid-Open No. 63-28).
No. 46). However, it is obvious that this method requires investment in new equipment such as a noro storage tank and piping for recycling noro, and it has not been put into practical use except for a few companies.

[0005] Therefore, most of the measures against slag already disclosed are measures to reduce the amount of slag. The principles of the proposed measures to prevent slag are roughly classified into the following four types (1) to (4). (1) The viscosity of the paste is increased by adding a thickener or a substance having a water retention property, and the amount of slag discharged is reduced.

(2) By adding a coagulant during the molding, the particles to be separated as slag are aggregated so that only water is discharged. (3) Add a setting hardening accelerator (material) to reduce slag emission. (4) Others As the method utilizing the thickening effect of the paste of the above (1), for example, a method of adding a cellulose compound and / or a polyacrylamide compound (JP-A-61-20)
No. 1649), a method of adding an air entraining agent and an inorganic fine powder composed of finely divided silica and clay (JP-A-63-103850).
JP-A-4-254458), or a method of adding an additive comprising a water-soluble salt of a styrene-maleic acid copolymer and a high-performance water reducing agent (see JP-A-4-254458). A method of adding an additive containing an amine or the like (see JP-A-6-183799) is disclosed.

As a method utilizing the agglomeration effect of the above (2), a bubble having a specific bubble density is formed using a polyacrylamide-based flocculant and an anionic surfactant or a nonionic surfactant. A method of injecting during molding (see JP-A-63-60141), a method of adding a partially hydrolyzed polyacrylamide having a molecular weight of 30 to 100,000 and a hydrolysis rate of 5-35% during molding (see No. 5-306154).

As the method utilizing the setting and hardening accelerator (material) of the above (3), a method of adding an additive consisting of a high-performance water reducing agent and a thiosulfate (see JP-A-6-9256) And a method of blending a metal sulfate such as Kalimeiban or aluminum sulfate (see Japanese Patent Publication No. 5-17195). As another method utilizing the above-mentioned principle (4), by adding type II anhydrous gypsum, a water reducing agent and polyethylene glycol, the ratio of water / binder during kneading concrete is reduced, and the amount of slag is reduced. An example is a method of reducing the amount (see Japanese Patent Publication No. 7-115910).

In the production of mortar or concrete, it is necessary that the fluidity (hereinafter referred to as slump) and strength satisfy predetermined values. In addition to this, it is necessary to reduce the amount of slag discharged. Is required. However, none of the above methods simultaneously satisfy these three conditions.

Another problem is that the required amount of the admixture (admixture) to be used is large and the concrete becomes expensive. For these reasons, the above-mentioned prior art slag reducing agent is hardly used, and at present, most of the slag is treated as industrial waste.

[0011]

An object of the present invention is to significantly reduce the amount of slag discharged without reducing the slump of the cement composition and the strength of the obtained concrete or mortar. Provided is a method for producing a cement composition for centrifugal force molding of concrete or mortar, which satisfies the conditions simultaneously and is inexpensive and industrially usable, and a cement composition for centrifugal force molding obtained by the production method An object of the present invention is to provide a mortar or concrete centrifugal force molded product using a material.

[0012]

That is, a first aspect of the present invention relates to the following A component, B component, cement, water and fine aggregate,
Or a method for producing a cement composition containing a coarse aggregate, further comprising kneading the A component, cement, water and fine aggregate, or the coarse aggregate additionally, and then adding and kneading the B component. , Yield value of the cement composition = (0.85 to
1.15) × (yield value of reference cement composition) and plastic viscosity of said cement composition = (1.5-5.0) × (plastic viscosity of reference cement composition) This is a method for producing a composition.

A component: a water reducing agent and / or a high performance water reducing agent B component: a thickener Reference cement composition: a cement composition comprising A component, cement, water and fine aggregate, or additionally coarse aggregate. Cement, water, fine aggregate and coarse aggregate of the cement composition in the cement composition and the water reduction rate, respectively, the cement, water, fine aggregate and coarse aggregate of the cement composition for centrifugal force molding. A cement composition having the same mixing ratio and water reduction rate.

[0014] In the first invention, the component A, cement, water and fine aggregate, or further, coarse aggregate,
After kneading for 1 to 300 seconds, it is preferable to add the B component and knead for 10 to 300 seconds. Further, in the first invention, it is preferable that the centrifugal force forming cement composition is a centrifugal force forming cement composition having the following composition ratio.

A component / cement (weight ratio) = 0.001 to 0.012 B component / cement (weight ratio) = 25 × 10 ⁻⁸ to0.05 water / cement (weight ratio) = 0.25 to 0.45 water: 120 to 180 kg / m ³ -(Concrete or mortar) Further, in the first invention, it is more preferable that the centrifugal force forming cement composition is a centrifugal force forming cement composition having the following compounding ratio.

A component / cement (weight ratio) = 0.001 to 0.012 B component / cement (weight ratio) = 25 × 10 ⁻⁸ to0.05 water / cement (weight ratio) = 0.25 to 0.45 water: 120 to 180 kg / m ³ -(Concrete or mortar) Fine aggregate ratio = [fine aggregate / (fine aggregate + coarse aggregate)] x 100 = 30
-100 volume% In the first invention, it is preferable that the weight average molecular weight of the component B is 5,000 to 5,000,000.

A second aspect of the present invention is a centrifugally formed mortar or concrete obtained by centrifugally molding the cement composition produced by the method for producing a cement composition for centrifugal force molding according to the first aspect of the present invention.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a cement composition for centrifugal molding according to the present invention (hereinafter referred to as the method of the present invention),
The mortar or concrete centrifugal molding using the centrifugal molding cement composition produced by this method will be described in detail. The present inventors have at the same time the three conditions of drastically reducing the amount of slag discharged without reducing the slump of the cement composition, which is the object of the present invention, and the strength of the obtained concrete or mortar. Various conditions necessary for satisfying were examined.

As a result, the following findings (1) to (3) were found, and the present invention was completed. (1) In order not to reduce the strength and durability of mortar or concrete (hereinafter also referred to as concrete),
A cement composition kneaded with the addition of only a water reducing agent and / or a high performance water reducing agent, i.e., a water reducing agent and / or a high performance water reducing agent, cement, water and fine aggregate, or additionally a coarse aggregate. It is most preferable that centrifugal molding is performed under substantially the same conditions as a cement composition (hereinafter, referred to as a reference cement composition).

(2) In order to greatly reduce the amount of slag without lowering the slump, the yield value and the plastic viscosity of the cement composition are set to 0.85, respectively, with respect to the yield value and the plastic viscosity of the following standard cement composition. ~ 1.15 times and 1.5 ~
It must be 5.0 times. Reference cement composition: a cement composition comprising the A component, cement, water and fine aggregate, or additionally coarse aggregate, without the B component, wherein the cement, water,
The mixing ratio and water reduction rate of fine aggregate and coarse aggregate, respectively,
A cement composition equal to the mixing ratio of each of cement, water, fine aggregate and coarse aggregate and the water reduction rate of the cement composition for centrifugal force molding.

(3) The yield values and plastic viscosities of the cement compositions were each set to 0.
In order to obtain 85 to 1.15 times and 1.5 to 5.0 times, A.I. B. water reducing agents and / or high performance water reducing agents (hereinafter referred to as high performance water reducing agents); It is necessary to add both of the thickeners, and further, it is necessary to make the order of adding the high-performance water reducing agents and the thickener specific.

It is preferable that the molecular weight of the thickener is in a specific range. The present invention is not limited to the method for measuring the yield value and the plastic viscosity of the cement composition, but the present inventors, for simplicity, the following formulas (1), (2)
Yield values and plastic viscosities defined in (1) were used (references: [Kurokawa et al., Annual Report of Concrete Engineering, 16
(1), 437 (1994)], [Kuroiwa et al., Annual Report of Concrete Engineering, 18 (1), 437 (1996)], [Tanikawa et al., Report of the Architectural Institute of Japan, Tokai Branch, February 1993, p. .9]).

[0023]

(Equation 1)

Where ρ: density of cement composition [kg / m ³ ] G: gravitational acceleration [m / s ² ] V: volume of slump cone [m ³ ] Sf: slump flow [cm] a: slump cone A = 9.59 × 10 ⁻³ [m ² / s ² ] β: plug flow parameter, β = 1 − [(4τ _y ) / (3τ _R )] + [(τ _y /
τ _R) ^4/3] tau _R: marginal conditions the cement composition is closed by the funnel
[Pa] When a slump cone is used as a funnel, τ _R /ρ=0.376 [m ² / s ² ] t: time for the cement composition to flow down the funnel [s] The flow time t was measured upside down. A slump cone was used.

Since the cement composition is a non-Newtonian fluid, the yield value and the absolute value of the plastic viscosity vary depending on the measuring method and measuring conditions. Therefore, it is appropriate to use those relative values as essential components of the present invention. Here, the relative value of the yield value and the plastic viscosity of the cement composition for centrifugal force molding according to the present invention with respect to the yield value and the plastic viscosity of the reference cement composition (hereinafter, referred to as the specific yield value and the specific plastic viscosity), It is defined by the following equations (3) and (4).

Specific yield value R (τ _y ) = (τ _y ) ₁ / (τ _y ) ₀ (3) where (τ _y ) _{1 is the} centrifugal force-forming cement composition according to the present invention. Yield value (τ _y ) ₀ : Yield value of reference cement composition Specific plastic viscosity R (η) = (η) ₁ / (η) ₀ (4) where (η) ₁ : the present invention The plastic viscosity of the cement composition for centrifugal force forming according to (η) ₀ is the plastic viscosity of the reference cement composition. Therefore, the essential component of the present invention is “the yield value of the cement composition = (0.85 to 1.15) × ( Yield value of reference cement composition), and plastic viscosity of the cement composition =
(1.5 to 5.0) x (plastic viscosity of reference cement composition) "
Means that the specific yield value R (τ _y ) is 0.85 to 1.15 and the specific plastic viscosity R (η) is 1.5 to 5.0.

That is, the yield value and plastic viscosity of the cement composition produced by the method of the present invention are 0.85 to 1.15 times and 1.5 times that of the reference cement composition, respectively.
~ 5.0 times, 0.90 ~ 1.10 respectively
It is particularly preferred that the ratio is 1.6 times to 4.0 times. When the specific yield value is less than 0.85, the slump of the cement composition is excessive, and the amount of slag increases, which is not preferable.

If the specific yield value exceeds 1.15, the amount of slag decreases, but the slump of the cement composition becomes too small, so that the workability is lowered and the strength of the product is lowered, which is not preferable. On the other hand, when the specific plastic viscosity is less than 1.5, the rate of reduction of the amount of noro is insufficient, which is not preferable.

When the specific plastic viscosity exceeds 5.0, the cement composition becomes a very viscous cement composition, so that workability is remarkably reduced and molding defects are apt to occur, which is not preferable. next,
Each component constituting the cement composition for centrifugal force forming according to the present invention will be described. (Component A: water reducing agent and / or high performance water reducing agent) As the component A (water reducing agent and / or high performance water reducing agent), those generally used as cement dispersants can be used.

That is, for example, a water-soluble salt of naphthalenesulfonic acid formalin condensate, an alkylallyl sulfonate formalin condensate, a water-soluble salt of olefin-unsaturated zircarboxylic acid copolymer, lignin sulfonate, lignin sulfonic acid and Examples include a water-soluble salt of a formalin co-condensate of naphthalene sulfonic acid, a water-soluble salt of a formalin co-condensate of a sulfonated product of creosote oil, and a water-soluble salt of a melamine sulfonic acid formalin condensate.

In addition, compounds obtained by adding a side chain such as a polyoxyethylene chain to these compounds, and compounds obtained by crosslinking these compounds can also be used. Further, in the present invention, the above-mentioned various A components may be used in combination. As the salt in the above-mentioned various A components, a water-soluble alkali metal salt may be used, but a Na salt can be most generally used.

More specifically, naphthalenesulfonic acid formalin condensate “KFLOW S-110” (trade name, manufactured by Kawasaki Steel Corporation), and ligninsulfonic acid “Sunflow K” (: commercial product) Name, manufactured by Sunflow Co., Ltd.), "Mighty 3000" (trade name, manufactured by Kao Corporation) in which a polyoxyethylene side chain is added to a polycarboxylic acid group-containing main chain, melamine sulfonic acid formalin condensate "Sekament F"
F "(trade name, manufactured by Sika Japan Co., Ltd.) and the like may be used in combination.

The component A is used in an amount of 0.
It is preferably added in an amount of 1 to 1.2 parts by weight,
Particularly preferred is 1.0 part by weight. If the amount is less than 0.1 part by weight, the dispersion of the cement particles is insufficient, so that the amount of slag is reduced. When the amount exceeds 1.2 parts by weight, the water reduction rate is high, but the concrete becomes rice cake-like and the workability is remarkably reduced, which is not preferable. In addition, the amount of slag generated also increases.

(Component B: Thickener) As the component B (thickener), the specific yield value and the specific plastic viscosity of the cement composition for centrifugal force forming according to the present invention are 0.85 to 1.15, respectively.
Any thickening agent having a viscosity of 1.5 to 5.0 may be used. Specifically, water-soluble acrylic acid polymers such as polyacrylamide, water-soluble salts of copolymers of olefins and unsaturated carboxylic acids, cellulose ethers and derivatives thereof, and alkali-thickening polymer emulsions such as emulsions containing acrylic acid groups , Polyethers such as polyethylene oxide and derivatives thereof, polyvinyl alcohol and derivatives thereof,
thickeners such as highly water-absorbing gels made by insolubilizing polysaccharides such as β-1,3-glucan and water-soluble polysaccharides, and water-soluble polymers such as polyacrylic acid by crosslinking and / or the like;
Alternatively, a separation reducing agent can be exemplified, and two or more of these may be used in combination.

Examples of the water-soluble salt of the copolymer of olefin and unsaturated carboxylic acid include a metal salt and an ammonium salt of a copolymer of olefin and unsaturated carboxylic acid. Examples thereof include alkali metal salts such as salts and K salts. Among these thickeners, glycol-based synthetic polymers belonging to the polyether series, for example, "C
AD3200 "(trade name, manufactured by Kao Corporation), etc., and a thickener having a low adsorptivity to cement and a cellulose ether-based separation reducing agent having an action of reducing friction between cement particles are used in cement. Although the increase rate of the specific yield value of the composition is small, the increase rate of the specific plastic viscosity is large,
Particularly preferred.

The component B has a weight average molecular weight of 5,000 to 500,000.
It is preferably 0, particularly preferably 100,000 to 100,000. When the weight average molecular weight of the component B is less than 5,000, the rate of increase in the specific plastic viscosity is small, so the effect of adding the thickener on the reduction of the slag is insufficient, and the weight average molecular weight is
If it exceeds 5000000, the rate of increase of the specific plastic viscosity becomes excessive, so that not only does the fluidity of the cement composition decrease,
Molding failure may occur, which is not preferable.

The preferred amount of the component B varies depending on the type of the thickener used, and cannot be specified uniformly, but the component B / cement (weight ratio) = 25 × 10 ^{−8 to} 0.05. Is preferred. For example, when a metal salt of a copolymer of an olefin and an unsaturated carboxylic acid is used as the component B, it is preferably added in an amount of 25 × 10 ^{−6 to} 0.06 parts by weight based on 100 parts by weight of cement, and 50 × 10 6 Particularly preferred is from ^{-6 to} 0.05 part by weight.

When polyethylene glycol is used as the component B, 1 × 10
^{-4 to} 0.1 part by weight, preferably 5 × 10
Particularly preferred is ^{-4 to} 0.08 parts by weight. Also, β-1,3-
When glucan is used as the component B, it is preferably added in an amount of 1 × 10 ^{−3 to} 1.5 parts by weight, particularly preferably 5 × 10 ⁻³ to 1 part by weight, based on 100 parts by weight of cement.

The preferred range of the added amount of the component B varies depending on the type of the component B used. Insufficient, if the amount exceeds the upper limit of the preferred range, the rate of increase of the specific plastic viscosity is excessive,
It is not preferable because the fluidity of the cement composition decreases.
Further, the strength of the product may be reduced, which is not preferable.

(Other Additives, Additives) In the present invention, a setting hardening accelerator, a slump-retaining agent, or both of them can be used in combination with the components A and B, which are admixtures. By using these together, the specific plastic viscosity can be increased without increasing the specific yield value of the cement composition, so that the addition amount of the B component can be reduced, which is economical.

As the setting-hardening accelerator, any admixture may be used as long as it reduces the slump after the concrete is cast into the formwork. Specifically, formate, acetate, diethanolamine, triethanolamine, thiocyanate, calcium chloride, sodium chloride, potassium chloride, calcium nitrate, sodium nitrate, potassium nitrate, calcium nitrite, sodium nitrite, potassium nitrite, sulfuric acid It is preferably at least one selected from the group consisting of calcium, sodium sulfate, and potassium sulfate.

Of these, formate, diethanolamine, triethanolamine, thiocyanate, calcium nitrate, sodium nitrate, calcium sulfate, and sodium sulfate are particularly preferable because they are effective in preventing rust of reinforcing steel and are inexpensive. In addition, it is preferable to use an alkali metal salt, an alkaline earth metal salt, and an ammonium salt as the salt in the formate, acetate, and thiocyanate.

The slump holding agent may be any admixture that prevents the slump from dropping until the concrete is poured into the formwork. Specifically, high-molecular-weight organic acid salts such as ligninsulfonate, humate and tannate, having a molecular weight of 50
O-carboxylates such as polyacrylate, gluconate, glucoheptonate, citrate, etc., aminocarboxylates such as glutamate, saccharides, molecular weight of 0 to 5000
Preferred are polyethylene glycols, borates and silicofluorides of 500-5000, among which high-molecular-weight organic acid salts such as ligninsulfonate and humate, and having a molecular weight of 500-5000.
Oxycarboxylates such as 5000 polyacrylate and gluconate, and polyethylene glycol having a molecular weight of 500 to 5,000 are particularly preferred because they can be added in a small amount and are water-soluble.

If the molecular weight of the polyacrylate or polyethylene glycol is less than 500, the slump holding effect is low, and it is difficult to cast into a mold. If the molecular weight exceeds 5,000, stickiness increases, which is not preferable. . A suitable amount of the setting hardening accelerator and / or the slump holding agent is:
The total amount is 125 x 100 parts by weight of cement.
Preferably, 10 ^{-6 to} 0.25 parts by weight are added, and 250
It is particularly preferred that the amount be from × 10 ^{−6 to} 0.20 part by weight.

When the addition amount of the setting-hardening accelerator and / or the slump-retaining agent is less than 125 × 10 ⁻⁶ parts by weight, the fluidity is high, but the rate of increase of the specific plastic viscosity is insufficient, so that the slag reduction effect is obtained. Is insufficient and not preferred. Conversely, if the amount exceeds 0.25 parts by weight, not only is the slump reduced, but also the amount of slag generated is undesirably increased.

In the present invention, various admixtures,
For example, a binder containing a high-strength admixture, fly ash, silica fume, blast furnace slag, expander, or the like can also be used. By adding a fine powder admixture or binder, the specific plastic viscosity can be adjusted to 1.5 to 5.0 with a smaller addition amount of the B component, which is economical.

Examples of such admixtures and binders for the fine powder include silica fume, blast furnace slag fine powder, limestone powder, fly ash fine powder obtained by collecting fine particles only by a method such as classification, and rice husk. Examples thereof include fine particle cement (average particle diameter of about 10 μm) and ultrafine particle cement (average particle diameter of about 4 μm) used for injection of ash and ground improvement.

The suitable blending amount of the admixture and the binder for these fine powders cannot be specified uniformly because they vary greatly depending on the average particle size, particle size distribution, particle shape and the like of the fine powder used. For example, when using silica fume which is an ultra-fine powder, it is preferable to replace 0.01 to 10% by weight, more preferably 0.1 to 5% by weight of cement weight with silica fume, and a blast furnace slag fine powder having a specific surface area of 8000 cm ² / g. When blast furnace slag is used, 0.1 to 30% by weight, more preferably 1 to 20% by weight of cement is preferably replaced with blast furnace slag fine powder. 1 to 40% by weight, more preferably 5%
Up to 35% by weight should be replaced with ultrafine cement.

The preferred blending amount of these fine powders varies depending on the type of fine powder used. In any case, when the blending amount of the fine powder is less than the lower limit of the preferred range, the rate of increase in the specific plastic viscosity is small. If the effect of adding the powder is insufficient, and conversely if the upper limit of the preferred range is exceeded, the rate of increase of the specific plastic viscosity becomes excessive, so that not only the fluidity of the cement composition is reduced, but also molding failure occurs. Is not preferred.

If the content exceeds the upper limit of the preferable range, the concrete becomes expensive, which is not preferable. (Cement) As the cement, cements such as ordinary Portland cement, blast furnace cement, fly ash cement, early-strength cement, and particle size adjusting cement are used.

(Aggregate :) As the aggregate, fine aggregate (: sand, for example) and coarse aggregate (: gravel, etc.) usually used in this technical field may be used. In addition, although not limited at all, by using an aggregate having a large amount of adhered paste,
The specific plastic viscosity can be adjusted to 1.5 to 5.0 with a smaller addition amount of the B component, which is economical.

As such aggregates, there are coarse aggregates having many irregularities and voids on the surface, such as naturally crushed surfaces and cut surfaces, coarse aggregates having a high paste adhesion strength, such as limestone, and surfaces subjected to hydrophilic treatment. Coarse aggregate in which the interfacial tension between the aggregate and paste is reduced, or the aggregate with a large specific surface area and the aggregate with a nearly spherical shape are mixed to meet the standard for coarse aggregate for concrete Aggregates and the like can be exemplified.

The amount of the paste attached to the coarse aggregate is preferably 1 to 500% by weight, more preferably 5 to 400% by weight, when a general coarse aggregate is used. If the amount is less than 1% by weight, the reduction ratio of the added amount of the B component is low and it is not economical.
Not preferred. In addition, if it exceeds 500% by weight, the rate of increase of the specific plastic viscosity becomes excessive, so that not only the fluidity of the concrete decreases, but also molding failure may occur,
Not preferred.

Also, the combined amount of the component B can be reduced by using a combination of changes such as a change in the unit water amount and the fine aggregate ratio, which is economical. In this case, the flow rate of the cement composition and the resulting mortar, the strength of the concrete, it is better to reduce the unit water amount within a range that does not reduce the durability, and to increase the fine aggregate ratio, the increase rate of the specific plastic viscosity Is large and suitable.

[0055] The cement composition of the present invention comprises other admixtures,
For example, it can be used in combination with an AE agent, an AE water reducing agent, a foaming agent, a retarder, a curing accelerator, a swelling agent, an antifoaming agent, a dispersant, a surfactant, and the like. (Manufacturing method of cement composition :) As for the order of adding the A and B components, the A component is added and kneaded, then the B component is added and kneaded.

That is, it is preferable to add the component A,
A component, cement, aggregate, and water are kneaded for up to 300 seconds, more preferably for 10 to 240 seconds, particularly preferably for 30 to 120 seconds, and then the B component is added immediately and preferably for 10 to 300 seconds.
Component A, component B, and particularly preferably 30 to 240 seconds.
Knead cement, aggregate and water. If the component B is added at the same time as the component A or before the component A, the adsorption of the component A to the cement particles is inhibited and the slump is lowered, which is not preferable. Further, the strength may be reduced, which is not preferable.

If the kneading time after the addition of the component A is less than 1 second, the adsorption of the component A to the cement particles is insufficient, and the slump is lowered, which is not preferable. Conversely, the kneading time
If the time is longer than 300 seconds, the slump is reduced, which is not preferable. If the kneading time after the addition of the B component is less than 10 seconds, the dispersion of the B component in the concrete becomes insufficient, and the strength decreases, which is not preferable. Conversely, the kneading time is 3
If the time is longer than 00 seconds, the slump decreases, which is not preferable.

The method of adding the components A and B is not particularly limited, but the most common method is to dissolve each component in kneading water in advance and then add the components. In the present invention, the composition of the cement composition varies depending on the purpose, and may be a commonly used composition, and is not limited at all. For example, in the case of a pile, cement: water: fine aggregate: coarse aggregate = 450 to 500: 145 to 15
5: 650 to 750: 1000 to 1200 [kg / m ³ -concrete] It is preferable to mix the components A and B with cement, water, fine aggregate, and coarse aggregate. : Water: fine aggregate: coarse aggregate = 350 to 450: 145 to 155: 70
It is preferable to mix the components A and B with cement, water, fine aggregate and coarse aggregate having a mixing ratio of 0 to 800: 1000 to 1200 [kg / m ³ -concrete].

(Centrifugal force forming :) Next, the centrifugal force forming according to the present invention and the centrifugal force formed body of the present invention will be described. The physical properties and centrifugal molding conditions of the cement composition used in centrifugal molding are different depending on the centrifugal molding company, so the type and amount of the admixture used in the cement composition according to the present invention, the added amount, molecular weight, bone The type of the material, the type and the amount of the admixture and binder of the fine powder described above are selected from the preferable range of the cement composition according to the present invention, depending on the physical properties and centrifugal molding conditions of the cement composition used. It is possible to select the optimum type, addition amount, blending amount, molecular weight, and the like.

[0060] The kneaded cement composition is put into a mold and compacted by centrifugal force. The centrifugal force molding conditions are as follows:
Normal conditions may be used. For example, in the case of a pole or a pile, a low speed of 2 to 5 G is used for 2 to 5 minutes, and then a medium speed of 5 to 15 G
For 2 to 6 minutes, and finally by rotating at a high speed of 15 to 35 G for 4 to 10 minutes. Even if the high-speed molding conditions are set lower than usual by 2 to 10 G, the molded article of the present invention does not decrease in strength.

Therefore, it is preferable to reduce the centrifugal force at the time of molding, since the amount of slag generated can be further reduced and noise during molding can be reduced. The concrete after the centrifugal force molding is cured by an ordinary method such as underwater curing, steam curing, or autoclave curing, and becomes a product.

[0062]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the specific details described in these Examples. (Example 1) Na salt of a naphthalenesulfonic acid formalin condensate was added as an A component in the present invention to 5 components of the following blending amounts constituting a cement composition for centrifugal force molding, and
Kneaded for seconds.

Ordinary cement (manufactured by Mitsubishi Materials Corporation): 337 kg / m ³ -Concrete silica powder (manufactured by Nippon Cement Corporation): 92 kg / m ³
- Concrete Tap water: 159 kg / m ³ - concrete pit sand (Ichihara production): 714kg / m ³ - concrete limestone crushed stone (Tsukumi production): 1061kg / m ³ - Concrete Next, as component B in the present invention, the polyethylene glycol The mixture was added and kneaded for 100 seconds to obtain a cement composition.

Table 1 shows the amounts of the components A and B added. Immediately after kneading, slump, slump flow, and air volume were measured according to JIS A 1101 and JIS A 1128. Next, the slump cone was turned upside down to form a funnel, which was filled with the cement composition, and the time required for the cement composition to flow down from the funnel was measured.

Further, using a mold having an outer diameter of 20 cm and a height of 30 cm according to JIS A 1136, a 4 cm thick concrete centrifugal force specimen was prepared. Centrifugal molding was performed by rotating at a low speed of 1G for 6 minutes, then at a medium speed of 6G for 4 minutes, at a medium speed of 15G for 3 minutes, and finally at a high speed of 35G for 3 minutes. Further, the compressive strength of the obtained molded body was measured at a standard curing material age of 28 days.

Comparative Example 1 described below, which was prepared by blending the A component and the 5 components without adding the B component, corresponds to the reference cement composition in this example. Based on the yield value and the plastic viscosity measured in Comparative Example 1, the specific yield value and the specific plastic viscosity were determined according to the above-mentioned equations (3) and (4). Table 1 shows the obtained results.

Further, based on the amount of slag generated in Comparative Example 1 and the compressive strength of the molded product, the slag generation rate and the specific strength defined by the following formulas (5) and (6) are used to determine the slag generation. And the compressive strength of the centrifugally molded specimens were compared.
Table 1 shows the obtained results. In addition, a reference | standard concrete means what formed the reference | standard cement composition by centrifugal force.

Specific slag generation rate = [(slag generation amount) / (slag generation amount of reference cement composition)] × 100 (5) Specific strength = [(compressive strength) / (compressive strength of reference concrete)] × 100 (6) (Comparative Example 1) A cement composition was produced and evaluated in the same manner as in Example 1 except that the component B was not added.

Table 1 shows the obtained results. (Comparative Example 2) A cement composition was obtained by simultaneously adding ordinary cement, quartzite powder, tap water, mountain sand, limestone crushed stone, the component A and the component B, and kneading for 180 seconds to obtain a cement composition.
The same evaluation was performed.

Table 1 shows the obtained results. (Comparative Example 3) Ordinary cement, quartzite powder, tap water, mountain sand, limestone crushed stone, and the B component were added and kneaded for 80 seconds. Next, the component A was added and kneaded for 100 seconds to obtain a cement composition.

Example 1 of the obtained cement composition
The same evaluation was performed. Table 1 shows the obtained results. (Examples 2 to 11) A cement composition was produced and evaluated in the same manner as in Example 1 except that the kneading time of the A component and the B component was changed.

Table 1 shows the obtained results. (Examples 12 to 14) (Comparative Examples 4 to 9) A cement composition was produced and evaluated in the same manner as in Example 1 except that the types and amounts of the components A and B were changed (Example 12). ~14). In addition, A component and B component were added simultaneously,
A cement composition was manufactured and evaluated in the same manner as in Example 14 (Comparative Examples 4, 6, and 8).

The results obtained are shown in Table 2 together with the reference cement compositions to which the component B was not added (Comparative Examples 5, 7, and 9). Note that the water reduction rates of the cement compositions in Examples 1 to 14 and Comparative Examples 1 to 9 represented by the following formula (7) were all 17.5.
%Met. Water reduction rate = ｛[(moisture content in cement composition not containing A component)-(moisture content in cement composition containing A component)] / [moisture content in cement composition not containing A component] ｝ × 100 (%)… (7) As shown in Tables 1 and 2, by setting the specific yield value and specific plastic viscosity within the range of the present invention, the specific strength is within the error range with the value of the reference concrete In contrast, the specific slag generation rate was 39 or less, which enabled a significant reduction in slag.

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[Table 1]

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[Table 2]

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[Table 3]

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According to the method for producing a cement composition for centrifugal force forming of the present invention, a high slag reduction effect is exhibited without reducing the strength of the slump, concrete and mortar of the cement composition. Since the slag treatment cost tends to increase year by year, according to the production method of the present invention, the slag treatment cost can be significantly reduced.

Furthermore, since the amount of noro, which is industrial waste, is greatly reduced, which is useful for protecting the global environment, the industrial value of the present invention is very large.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 103: 32 103: 44

Claims (5)

[Claims] 1. A method for producing a cement composition containing the following A component, B component, cement, water and fine aggregate, or additionally a coarse aggregate, comprising: A component, cement, water and fine aggregate , Or in addition, after kneading the coarse aggregate,
The B component is added and kneaded, and the yield value of the cement composition =
(0.85 to 1.15) x (yield value of reference cement composition), and the plastic viscosity of the cement composition = (1.5 to 5.0) x
(Plastic viscosity of a reference cement composition). A component: a water reducing agent and / or a high performance water reducing agent B component: a thickening agent Reference cement composition: a cement composition comprising A component, cement, water and fine aggregate, or additionally coarse aggregate. The cement composition, water, fine aggregate and coarse aggregate of the cement composition in the cement composition and the water reduction rate are the same as the cement, water, fine aggregate and coarse aggregate of the centrifugal force forming cement composition. And a cement composition equal to the water reduction rate. 2. The kneading of component A, cement, water and fine aggregate, or additionally coarse aggregate for 1 to 300 seconds,
The method for producing a cement composition for centrifugal molding according to claim 1, wherein the component B is added and kneaded for 10 to 300 seconds. 3. The method for producing a cement composition for centrifugal force forming according to claim 1, wherein the cement composition for centrifugal force forming has the following compounding ratio. Serial component A / cement (weight ratio) = 0.001 to 0.012 Water / cement (weight ratio) = 0.25 to 0.45 water: 120 ~180kg / m ³ - (concrete or mortar) 4. The weight average molecular weight of the component B is from 5,000 to
The method for producing a cement composition for centrifugal forming according to any one of claims 1 to 3, wherein the cement composition is 5000000. 5. A centrifugally molded mortar or concrete obtained by centrifugally molding a cement composition produced by the method for producing a cement composition for centrifugal force molding according to claim 1.