JPH0930852A - Concrete admixture capable of reducing lime wash - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a concrete admixture to which lime wash lowering ability is imparted while satisfying cement dispersing ability required as a high- performance water reducing agent. SOLUTION: This concrete admixture capable of reducing lime wash contains the following components A and B. The component A: a water-reducing agent and/or a high-performance water-reducing agent. The component B: a polymer having 10000-30000000 weight-average molecular weight and being water-soluble under alkaline conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete admixture used in the production of concrete products such as concrete piles, poles, steel pipe composite piles, fume pipes, and steel pipe linings that are formed by utilizing centrifugal force.

[0002]

2. Description of the Related Art Conventionally, concrete piles and poles,
Concrete products such as fume pipes are manufactured by compacting and compacting by centrifugal force (hereinafter, these products are collectively referred to as centrifugally molded products). In the centrifugal molding process, the water in the concrete is squeezed out to produce a dense structure,
This water is mixed with cement and fine powder in aggregate and is discharged as so-called slag. In particular, in a pile or the like that requires high strength, a large amount of high performance water reducing agent is added, so that the amount of slag is large and the tightness of the mortar layer on the inner surface of the pipe is deteriorated.

Since this Noro is strongly alkaline, the solid content must be treated as industrial waste after sedimentation and separation / neutralization. Therefore, not only a large amount of cost is required, but also it has become difficult to secure a disposal place for the slag recently, which is a big problem for the centrifugal molding industry. Therefore, a method of reusing slag as a raw material for concrete products has been disclosed (Japanese Patent Laid-Open No. 63-2846). However, it is obvious that this method requires new capital investment such as savings of Noro and piping for recycling Noro, and it has not been put to practical use except for a few companies. Therefore, most of the measures against slag that have already been disclosed are measures to reduce the amount of slag.

The principle of the proposed measures for preventing slag generation is as follows: (1) The viscosity of the paste is increased by adding a thickener or a substance having water retention property, and the discharge of slag is reduced. (2) By adding a coagulant during molding, the particles that separate as slags are aggregated so that only water is discharged. (3) Others are roughly classified into three types. Examples of utilizing the thickening effect of the paste of (1) include, for example, a method of adding a cellulosic compound and / or a polyacrylamide compound (JP-A-61-201649), an air entraining agent and finely divided silica, and A method of adding inorganic fine powder made of clay (Japanese Patent Laid-Open No. 63-103850), or a method of adding a neutral polymer dispersion such as styrene-butadiene rubber and ethylene vinyl acetate and inorganic fine powder (Japanese Patent Laid-Open No. 5-103850). No. 24031) is disclosed.

Further, as a method utilizing the aggregating effect of (2), a polyacrylamide type aggregating agent and an anionic surfactant or a nonionic surfactant are used to form bubbles having a specific bubble density, and the bubbles are formed. Is injected during molding (Japanese Patent Laid-Open No. 63-60141), and a method of adding a partial hydrolyzate of polyacrylamide having a molecular weight of 30 to 100,000 and a hydrolysis rate of 5 to 35% during molding (Japanese Patent Laid-Open No. Hei 6 (1999) -58242). No. 5-306154) and the like are disclosed.

Further, as a method utilizing the other principle of (3), a method of adding thiosulfate which is a hardening accelerator for concrete (JP-A-61-68361) and a method of adding caseins (Japanese Patent Publication No. 5-13896) is disclosed. However, all of these methods use a powder, or a chemical prepared by dissolving the powder in water in advance during concrete kneading or during molding, and the existing equipment is used for measuring and charging powder, or Powder melting equipment must be added, and capital investment is required.

Further, the drugs used in these methods are
It is a powder that easily agglomerates and easily becomes a so-called "mamako". Therefore, it takes a long time to dissolve in concrete kneading water or water, and from this point as well, the manufacturing cost of the product becomes high and there are many problems. For the reasons described above, the noro reduction agents disclosed in the above publications are rarely used, and most of them are currently treated as industrial waste.

[0008]

As described above, the drawbacks of the prior art are that (1) powder, or a drug obtained by dissolving powder in water in advance is added during concrete kneading or molding. , New equipment investment is required, and (2) concrete kneading water or powder that tends to become "Mamako" when dissolved in water requires a long time for dissolution, resulting in high cost. There are two points.

Further, it is generally difficult to handle powder, and a liquid chemical agent is desired as a slag reducing agent. Furthermore, while satisfying the cement dispersibility required as a high-performance water reducing agent, liquid chemicals that have been imparted with a slag reducing ability are equipped with measuring and charging equipment for concrete admixtures such as high-performance water reducing agents that have been used conventionally. Since it can be diverted as it is, its industrial value as a slag reducing agent is very high. However, nothing is known about such drugs.

In view of the above, the inventors of the present invention have found a concrete admixture having a slag reducing ability while satisfying the cement dispersing ability required as a high performance water reducing agent with only one liquid chemical. As a result of earnestly studying the purpose, the present invention has been completed. That is, the object of the present invention is:
It is intended to provide a concrete admixture having a slag reducing ability, and further to provide a concrete admixture having a slag reducing ability while satisfying the cement dispersibility required as a high performance water reducing agent.

[0011]

In order to solve the above-mentioned problems, the present inventors have maintained the fluidity of concrete,
As a result of intensive studies aimed at obtaining an admixture capable of reducing the amount of slag produced, the present invention has been completed.
That is, the first invention of the present invention is a concrete admixture capable of reducing slag, which is an aqueous emulsion containing the following A component and B component.

Component A: Water-reducing agent and / or high-performance water-reducing agent Component B: Weight-average molecular weight is 10,000 to 3,000,000, and
A polymer that becomes water-soluble under alkaline conditions. The second invention of the present invention is the following A component, B component and C
A concrete admixture capable of reducing slag, which is an aqueous emulsion containing the components.

Component A: Water-reducing agent and / or high-performance water-reducing agent Component B: Weight average molecular weight is 10,000 to 3,000,000, and
Aqueous polymer emulsion that becomes water-soluble under alkaline conditions C component: Aqueous polymer emulsion other than B component In the first and second inventions of the present invention,
The component A is a water-soluble salt of a formalin condensate of naphthalene sulfonic acid, a water-soluble salt of an olefin-unsaturated dicarboxylic acid copolymer, a lignin sulfonate, or a water-soluble formalin co-condensate of lignin sulfonic acid and naphthalene sulfonic acid. Water, a water-soluble salt of a formalin cocondensate of a sulfonate of creosote oil, a water-soluble salt of a formalin condensate of alkylallyl sulfonic acid, and a water-soluble salt of a formalin condensate of melamine sulfonic acid. Alternatively, two or more kinds of compounds are preferable.

Further, the polymer of the component B is preferably a polymer in which an acidic group is bonded to the molecular chain by using a monomer having an acidic group as a substituent as an essential copolymerization component. Particularly preferably, the monomer having an acidic group as is an unsaturated carboxylic acid monomer and / or an unsaturated sulfonic acid monomer.

Further, the polymer of the component B is a polymer emulsion in which a polymer molecular chain is carboxylated and / or sulfonated by using, as an essential component, an unsaturated carboxylic acid monomer and / or an unsaturated sulfonic acid monomer as a copolymerization component. Is preferred. Further, the polymer of the component B may be re-emulsifying polymer fine particles in which the polymer molecular chain is carboxylated and / or sulfonated by using an unsaturated carboxylic acid monomer and / or an unsaturated sulfonic acid monomer as a copolymerization component. preferable.

The other monomer copolymerizable with the acidic monomer is preferably an ethylenically unsaturated monomer. In the first aspect of the present invention, it is preferable that the concrete admixture is prepared by dissolving A component in 43 to 90 parts by weight and B component in 0.01 to 10 parts by weight in 100 parts by weight of water.

In the second aspect of the present invention, the aqueous polymer emulsion which is the C component may be ethylene vinyl acetate copolymer, polyvinyl acetate, styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer. It is preferable that the polymer emulsion comprises one kind or two or more kinds selected from the group consisting of coalescence.

Further, the component A is 43 parts with respect to 100 parts by weight of water.
˜90 parts by weight, 0.01 to 10 parts by weight of B component, and 1 to 99 parts by weight of C component in 100 parts by weight of the total of C component and B component are preferable to be a concrete admixture. .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A concrete admixture capable of reducing slag of the present invention (hereinafter referred to as an admixture of the present invention).
Will be described in detail. It is known that it is possible to reduce roe by thickening the paste (for example, Cement Industry, (216) 33, 1989). Therefore, the use of a thickener commonly used in the technical field related to concrete, such as cellulosic or polyacrylamide, can reduce slag. However, such conventional thickeners are replaced by water-reducing agents and / or high-performance water-reducing agents (hereinafter,
When it is dissolved in a high-performance water reducing agent), it hardly dissolves, or even if it dissolves, the viscosity of the aqueous solution after dissolution becomes high, and an admixture that can be put to practical use cannot be obtained.

Therefore, the present inventors have no substance to increase the viscosity in the neutral to weakly alkaline high-performance water-reducing agent, and in the strongly alkaline concrete, show a substance thickening effect necessary and sufficient for reducing slag. Were examined variously. As a result, by using a monomer having an acidic group as a substituent as a copolymerization component, the polymer has a weight average molecular weight of 10,000 to 3,000,000, and p
A polymer that becomes water-soluble in an alkaline aqueous solution with H of 9 or more has a low viscosity because it is a stable emulsion in a high-performance water reducing agent, but the polymer swells and dissolves in concrete with a large amount of calcium ions. Therefore, it was found that a thickening effect was exhibited.

[0021] Further, preferably, the components A and B are made to be specific substances and the concentration thereof is made to be in a specific range so that the cement dispersibility required as a high-performance water reducing agent can be satisfied and a high slag reduction ability can be obtained. It has been found that can be given. The admixture of the present invention is used by adding it during the production of concrete, like the high-performance water reducing agent which is usually used.

The admixture of the present invention is characterized in that it is a one-pack type chemical which has the ability to reduce slag while satisfying the cement dispersibility required as a high performance water reducing agent. The function of the high-performance water-reducing agent that is the A component is to impart the cement dispersibility, and the weight average molecular weight of the B component that is 10,000 to 3,000,000 and that of the polymer that becomes water-soluble under alkaline conditions. Its main function is to provide the ability to reduce slag.

Therefore, even if only the B component is added to the concrete alone, it exhibits a higher noro reduction ability than the conventional noro reduction agents. However, in that case, since the weighing and the charging equipment for charging the component B or the aqueous emulsion thereof into the concrete are required separately, the industrial superiority becomes low. The component B also has the function of improving the fluidity of concrete by the generation of fine bubbles, depending on the structure and polarity of the polymer.

The component A of the admixture of the present invention may be any as long as it can be used as a high-performance water-reducing agent, but it is a water-soluble salt of a naphthalenesulfonic acid formalin condensate or a water-soluble salt of an olefin-unsaturated dicarboxylic acid copolymer. , Lignin sulfonate, water-soluble salt of formalin co-condensate of lignin sulfonic acid and naphthalene sulfonic acid, water-soluble salt of formalin co-condensate of sulfonate of creosote oil, water-soluble salt of alkylallyl sulfonic acid formalin condensate , And one or more compounds selected from the group consisting of water-soluble salts of melamine sulfonic acid formalin condensates.

Further, since the admixture of the present invention is used for producing a centrifugally molded product, the component A is
A water-soluble salt of a formalin condensate of naphthalene sulfonic acid, a water-soluble salt of a formalin co-condensate of lignin sulfonic acid and naphthalene sulfonic acid, or a mixture thereof is particularly preferable as a high-performance water reducing agent. Said A
The salt in the component may be any water-soluble alkali metal salt, but the Na salt is most commonly used. Specifically, the product name “KFLOW S-11” manufactured by Kawasaki Steel Co., Ltd.
0 ”, a product name“ Mighty 150 ”manufactured by Kao Corporation, a product name“ Sunflow PSR ”manufactured by Sunflow Co., Ltd., and the like.

The component A in the admixture of the present invention is preferably contained in an amount of 43 to 90 parts by weight with respect to 100 parts by weight of water. If it is less than 43 parts by weight, the fluidity of concrete, which is usually expressed as a slump value, is low and it does not meet the criteria for a superplasticizer. If the amount of component A exceeds 90 parts by weight, the slump value is high, but the cement content in the slag is large, which is not preferable.
In addition, the admixture is expensive.

The component B of the admixture of the present invention may be any polymer as long as it has a weight average molecular weight of 10,000 to 3,000,000 and is water-soluble under alkaline conditions. A polymer having an acidic group bonded to its molecular chain by using a monomer having an acidic group as a substituent such as a sulfonic acid monomer as a copolymerization component is preferable.

As such a monomer, one or more selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, itaconic acid, maleic acid, crotonic acid, allylsulfonic acid, and styrenesulfonic acid are preferable. Although used, acrylic acid and / or methacrylic acid are more preferably used. Other monomers copolymerizable with these acidic monomers are preferably, but not limited to, ethylenically unsaturated monomers such as acrylic acid esters, methacrylic acid esters, itaconic acid esters, vinyl acetate, and styrene. One or more selected from the group are preferable.

Further, the polymer of the component B is a polymer emulsion in which the polymer molecular chain is carboxylated and / or sulfonated by using an unsaturated carboxylic acid monomer and / or an unsaturated sulfonic acid monomer as a copolymerization component, or these. It is particularly preferable to use re-emulsifying polymer fine particles of the polymer (1). In particular,
Product name "Ultrasol" manufactured by Ganz Kasei Co., Ltd.,
The product name “Movinyl” manufactured by Hoechst Gosei Co., Ltd. can be exemplified.

The copolymerization rate of the unsaturated carboxylic acid monomer and / or unsaturated sulfonic acid monomer in the component B is preferably 0.01 to 50 mol%, more preferably 0.1 to 40 m.
ol% is preferred. If it is less than 0.01 mol%, the thickening effect under alkaline conditions is low, and the ability to reduce slag is insufficient, and if it exceeds 50 mol%, the stability of the polymer emulsion decreases.

The weight average molecular weight of the B component must be 10,000 to 3,000,000. If the molecular weight is less than 10,000, the thickening effect is low, so the slag reducing ability is insufficient, and if it exceeds 3 million, the fluidity of concrete decreases. The component B is preferably contained in the admixture of the present invention in an amount of 0.01 to 10 parts by weight as the polymer of the component B with respect to 100 parts by weight of water. When the content of the B component is less than 0.01 part by weight, the addition effect of the B component for reducing the slag hardly appears, and when it exceeds 10 parts by weight, the slag reducing effect is large but the fluidity is lowered. In addition, the admixture is expensive.

The main function of the component B in the admixture of the present invention is, as already mentioned, the reduction of slag due to thickening of the paste, but when the weight average molecular weight of the component B is about 1,000,000 or more. Some of the fine particles in the cement agglomerate, so that the solid content in the Noro decreases. The reason that the fluidity of the concrete does not decrease even when the agglomeration effect appears is considered to be that the rate at which the B component becomes water-soluble under alkaline conditions is slow.

As the component B, a polymer having a single composition may be added to the admixture of the present invention, or two or more polymers having different compositions may be added. Further, the number of monomer components is not limited to binary polymers, and ternary polymers or higher multicomponent polymers can also be used. The method for producing the component B used in the present invention is arbitrary and various polymerization methods can be adopted, but it is usually produced by emulsion polymerization according to a conventional method. Emulsifiers are usually used in emulsion polymerization, but various emulsifiers such as anionic and nonionic emulsifiers can be used. The re-emulsifiable polymer particles are most commonly produced by spray-drying the emulsion obtained by emulsion polymerization.

A carboxylated polymer emulsion and / or a sulfonated polymer emulsion is used as the component B, any other polymer emulsion is used as the component C, and the components B and C are used as the polymer emulsion.
When a mixture of components is used, the C component is one or more selected from the group consisting of ethylene vinyl acetate copolymer, polyvinyl acetate, styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer. It can be illustrated.

The mixing ratio of the component C, which is an arbitrary polymer emulsion, is 1 to 99 parts by weight, preferably 10 to 90 parts by weight, based on 100 parts by weight of the total of the components B and C as a polymer. It is preferable. When the mixing ratio of the C component is less than 1 part by weight, the stability of the B component in the admixture is low, and when it exceeds 99 parts by weight, the slag reducing ability is insufficient.

Since the physical properties of the concrete used in centrifugal molding and the centrifugal molding conditions vary depending on the centrifugal molder, the content ratios of the components A, B and C in the admixture of the present invention and the polymerization of the B component and C component. Regarding the degree and the like, an optimum composition can be selected from the suitable range of the admixture of the present invention depending on the physical properties of the concrete used and the centrifugal molding conditions. In the admixture of the present invention, since the components A, B and C are usually produced as an aqueous solution and an aqueous emulsion,
A predetermined amount of the aqueous solution and the aqueous emulsion of each of the components A, B, and C is mixed so that the pure content of each of the components A, B, and C is within the preferred range of the present invention, and water is added if necessary. In addition, it can be manufactured by diluting.

Further, the admixture of the present invention may be produced by obtaining a pure content by an arbitrary method such as drying and then adding a predetermined amount of water and by an arbitrary method such as stirring. The stirring method is not particularly limited, but it is usually performed at room temperature to 90 ° C. for 1 to 6 hours. The viscosity of the admixture of the present invention thus produced is 10 to 10
The viscosity is about 0 cps, which is equivalent to that of a commonly used high-performance water reducing agent.

The admixture of the present invention is an aqueous emulsion containing the above-mentioned components A and B as a main component, or the above components A and B.
Aqueous emulsion containing C component and C component as main components, but other admixtures such as water reducing agents, AE agents, AE water reducing agents, foaming agents, retarders, hardening accelerators, swelling agents, defoaming agents, and interfacial agents. It is possible to use in combination with an activator and the like, and these other admixtures may be added to the admixture of the present invention in advance.

The admixture of the present invention is preferably used by adding 0.5 to 3 parts by weight to 100 parts by weight of cements.
If the amount is less than 0.5 part by weight, desired properties of concrete in terms of fluidity and slag reduction cannot be obtained. If the amount is more than 3 parts by weight, not only the setting retardation of the concrete is recognized, but also the admixture price is included. This is not preferable because the price of concrete becomes expensive. The addition method and the kneading method may be carried out by the methods generally used in this technical field, and are not limited at all.

The concrete thus kneaded is put into a form and compacted by centrifugal force. Centrifugal molding conditions may be those normally used, for example, for a pole or pile, low speed 2-5G for 2-5 minutes, then medium speed 5-15G for 2-6 minutes, and finally high speed 15-35G. 4-10
Do this by rotating for a minute. The concrete after centrifugal molding is cured by a normal method such as underwater curing, steam curing, and autoclave curing to obtain a product.

The admixture of the present invention is added to concrete, and as the cements, in addition to ordinary Portland cement, cements such as blast furnace cement, fly ash cement, and early-strength cement are used. In addition to cement, various admixtures such as fly ash, silica fume, blast furnace slag, and a curing agent containing an expanding agent can also be used as the admixture of the present invention, without any limitation.

[0042]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the specific details described in these examples. Table 2 shows the composition and performance test results of the admixture in this example. As the A component, an aqueous solution of Na salt of a naphthalene sulfonic acid formalin condensate, a product name “KFLOW S” manufactured by Kawasaki Iron and Steel Co., Ltd.
-110 "(denoted by A1 in Table 2), an aqueous solution of a water-soluble salt of a formalin cocondensate of ligninsulfonic acid and naphthalenesulfonic acid, manufactured by Sunflow Co., Ltd. under the trade name" Sunflow PSR "(Table 2), or a water-soluble salt of a melamine sulfonic acid formalin condensate, trade name “SECAMENT FF” manufactured by Nippon Sika Co., Ltd. (indicated as A3 in Table 2) was used as it was.

As the component B and the component C, emulsions (B1 to B11, C1 and C2) of the compounds shown in Table 1 and re-emulsifying fine particles (B12) were used (hereinafter, each of the abbreviations shown in Table 1 is used. The compound is described). Polymer emulsion of each compound (B1 to B12)
The polymer swelled in an alkaline aqueous solution having a pH of 9 or more and gradually dissolved.

With respect to the high molecular weight polymers such as B4, B5 and B8, some undissolved polymers remained even after being immersed in the alkaline aqueous solution for a long time. It is considered that the core portion of the polymer having an extremely small acidic group content remained, and this core portion is considered to be substantially equivalent to the C component. B1 and B5 are compounds used as comparative examples and having a weight average molecular weight outside the preferred range of the present invention. Here, the weight average molecular weight was measured by polystyrene permeation sodium salt standard by gel permeation chromatography.

In the examples, water is added as necessary to prepare water.
A so that the weight parts shown in Table 2 are 100 parts by weight,
Each of the B and C components was sampled to prepare an admixture, the viscosity of the admixture was measured with a B-type viscometer, and then concrete was prepared with the composition shown in Table 3. The admixture was kneaded and dissolved in water before use. After measuring the slump and the amount of air, a centrifugally-molded specimen having a concrete thickness of 4 cm was prepared in accordance with JIS A 1136 using a mold having an outer diameter of 20 cm and a height of 30 cm. The molding conditions are also shown in Table 3. The amount of slag is shown as a relative value with the amount of slag generated in Comparative Example 3 as 100.

Table 2 shows the slump and the relative amount of slump when the admixture of the present invention was used and when the admixture having a composition outside the preferred range of the present invention was used to clarify the effect of the present invention. . As is clear from this, when the admixture of the present invention was used, the slump satisfied the target value as in Comparative Example 3, and while maintaining the high fluidity required as a high performance water reducing agent. However, the relative amount of slag was 40 or less irrespective of the compounding-molding conditions and showed a remarkable slag reduction ability (Invention Examples 1 to
17 and 21). Further, the viscosity of the admixture is 100 cP or less, and the effect of the present invention is clear. On the other hand, when an admixture in which the concentrations of the components A and B were out of the preferred range of the present invention was used, the slump was reduced (Invention Examples 18 and 20) or the slag reduction ability was reduced (Invention Example 19). However, the noro reduction effect of Invention Examples 18, 19, and 20 was more remarkable than the noro amount in the case where the B component was not used (Comparative Example 3). Further, when the component A is not used (Comparative Example 4), the effect of reducing slag is large, but the slump is significantly reduced, and it is clear that the component is not effective as a high-performance water reducing agent.

The compressive strength of the sample using the admixture of the present invention was the same as that when a commercially available high-performance water reducing agent was added, and no adverse effects such as retardation of curing were shown.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

[Table 4]

[0052]

[Table 5]

[0053]

EFFECT OF THE INVENTION The admixture of the present invention is a one-pack type drug which has been imparted with the ability to reduce slag while satisfying the cement dispersibility required as a high-performance water reducing agent. The inlet to the tank for measuring the water reducing agent or the concrete mixer can be used as it is. Therefore, no new capital investment is required, and the slag processing cost can be significantly reduced as compared with the conventional technology. Furthermore, since the amount of noro, which is industrial waste, is significantly reduced, it is also useful for protecting the global environment. Therefore, the industrial value of the present invention is very large.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C04B 24/26 C04B 24/26 CG 24/30 24/30 D

Claims (7)

[Claims] 1. A concrete admixture capable of reducing porosity, which is an aqueous emulsion containing the following components A and B: A component: water reducing agent and / or high-performance water reducing agent B component: weight-average molecular weight of 10,000 to 3,000,000, and
A polymer that becomes water-soluble under alkaline conditions. 2. A concrete admixture capable of reducing slag, which is an aqueous emulsion containing the following A component, B component and C component. A component: water reducing agent and / or high-performance water reducing agent B component: weight-average molecular weight of 10,000 to 3,000,000, and
An aqueous polymer emulsion that becomes water-soluble under alkaline conditions. C component: An aqueous polymer emulsion other than B component. 3. A component is a water-soluble salt of a naphthalene sulfonic acid formalin condensate, a water-soluble salt of an olefin-unsaturated dicarboxylic acid copolymer, a lignin sulfonate, a formalin co-form of lignin sulfonic acid and naphthalene sulfonic acid. Selected from the group consisting of water-soluble salts of condensates, water-soluble salts of formalin co-condensates of sulfonated creosote oil, water-soluble salts of formalin condensates of alkylallyl sulfonic acid, and water-soluble salts of formalin condensates of melamine sulfonic acid. The concrete admixture capable of reducing slag according to claim 1 or 2, which is one or more compounds selected from the above. 4. The concrete admixture according to claim 1, wherein the polymer of the component B is a polymer containing a monomer having an acidic group as a substituent as an essential copolymerization component. 5. The slag can be reduced according to claim 4, wherein the monomer having an acidic group as a substituent, which is a copolymerization component of the component B, is an unsaturated carboxylic acid monomer and / or an unsaturated sulfonic acid monomer. Concrete admixture. 6. A component of 43 to 90 is added to 100 parts by weight of water.
The concrete admixture according to claim 1, 3, 4 or 5, which is obtained by dissolving 0.01 to 10 parts by weight of component B and component B. 7. A component of 43 to 90 is added to 100 parts by weight of water.
The weight component, 0.01 to 10 parts by weight of the B component, and 1 to 99 parts by weight of the C component in 100 parts by weight of the total of the C component and the B component are dissolved. Concrete admixture capable of reducing slag.