JP5587007B2 - Sulfuric acid resistant cement composition, sulfuric acid resistant mortar composition and sulfuric acid resistant concrete composition - Google Patents

Description

  The present invention is suitable for use in places where corrosion by sulfuric acid or sulfate is a problem, such as sewers, hot springs, chemical factories, and the like, and a sulfuric acid resistant cement composition with improved durability against acid rain, sulfuric acid resistance The present invention relates to a mortar composition and a sulfuric acid resistant concrete composition.

  In places where exposed to sulfuric acid or sulfate, such as sewers, hot springs, and chemical factories, corrosion of hardened cement by sulfuric acid or sulfate has been a problem. In recent years, corrosion of the entire structure using cement due to acid rain has also become a problem.

  Hardened cement (hardened cement paste, mortar, or concrete) forms a sparingly soluble and expandable gypsum when it comes into contact with sulfuric acid and dissolves silicic acid, alumina, etc. to produce silica or alumina gel To do. This action of sulfuric acid on the cement, which causes the expansive gypsum, silica and alumina gels to elute and easily breaks the hardened cement body, naturally depends on the acid concentration. When the pH exceeds 2 (sulfuric acid concentration of 0.1% or less), that is, when the acid concentration is low, corrosion by carbon dioxide gas or low concentration acid, or by salt showing corrosive properties such as sulfate Similarly, the penetration of corrosive substances into the interior can be suppressed by densifying the hardened cement, for example, by reducing the water-cement ratio while ensuring workability by using a high-performance AE water reducing agent. Thereby, corrosion resistance can be improved. However, when the concentration of sulfuric acid is high, it is difficult to cope only with the densification of the hardened cement. When the cement-hardened body is densified by lowering the water-cement ratio, there are fewer pores that relieve the expansion pressure due to crystal growth of gypsum produced by the acid. For this reason, for example, when the pH is very low, such as 2 or less, gypsum tends to peel off from the surface, and erosion may progress to deteriorate the corrosion resistance of the hardened cement body. The cement composition is expected to have resistance to acids. It is difficult to do.

  When pH is 2 or less (sulfuric acid concentration 0.1% or more), in order to prevent deterioration of the hardened cement body due to acid, the polymer cement in which the polymer is combined with the cement composition or the surface of the cement composition is corrosion resistant. An anticorrosion coating (lining) material that is coated with a material (for example, an epoxy resin or an unsaturated polyester resin) and prevents contact between a chemical corrosive substance (for example, sulfuric acid) and a cement composition is used. However, polymer cements and anticorrosion coatings are not only expensive, but are not general-purpose measures because they require special processes during production or construction. Even if there is a demand for sulfuric acid resistance, the cost may be more important than the improvement of sulfuric acid resistance if the cost becomes large.

  A water-soluble organic compound having an alkali metal salt of sulfonic acid as a substituent, specifically, a water-soluble organic compound containing an alkali metal salt of naphthalenesulfonic acid, as a cement composition from which a cured product having improved sulfuric acid resistance is obtained There is known a cement composition containing 0.5 to 4 parts by mass with respect to 100 parts by mass of cement (Patent Document 1).

Japanese Patent Laid-Open No. 10-236860

However, the cement composition of Patent Document 1 may cause material separation. Furthermore, further improvement in sulfuric acid resistance is desired.
Therefore, the present invention is simple in construction, provides a cured body with improved sulfuric acid resistance, and can suppress material separation, sulfuric acid resistant cement composition, sulfuric acid resistant mortar composition, and sulfuric acid resistant material. An object is to provide a concrete composition.

  The inventors of the present invention have studied various compounds that impart sulfuric acid resistance, and can improve the sulfuric acid resistance after curing of a cement composition, a mortar composition, or a concrete composition, and suppress material separation. The optimum compound that can be produced and its composition have been found and the present invention has been achieved.

The present invention is used at a pH of 2 or less exposed to sulfuric acid or sulfate, and 1.9 to 5 parts by mass of a formalin condensate of naphthalenesulfonic acid and / or a salt thereof with respect to 100 parts by mass of cement, and a weight average A sulfate-resistant cement composition comprising 0.13 to 20 parts by mass of an alkali metal salt of polystyrenesulfonic acid having a molecular weight of 10,000 to 2,000,000 , and using the same The present invention relates to a sulfuric acid resistant mortar composition and a sulfuric acid resistant concrete composition.

  The sulfuric acid resistant cement composition according to the present invention, and the sulfuric acid resistant mortar composition and sulfuric acid resistant concrete composition using the same have a formalin condensate of naphthalenesulfonic acid and / or a salt thereof, and an unsaturated ring. And an organic compound that is a polymer of a compound in which each ring of the unsaturated ring has one or more sulfo groups and / or a salt thereof is used in combination. As a result, the present invention does not require a special process during construction, is easy to construct, can suppress material separation, and improves the sulfuric acid resistance of a cured product obtained using these compositions. can do.

  The sulfuric acid resistant cement composition, sulfuric acid resistant mortar composition and sulfuric acid resistant concrete composition of the present invention will be described in detail.

  The sulfuric acid resistant cement composition of the present invention has 0.3 to 5 parts by mass of a formalin condensate of naphthalenesulfonic acid and / or a salt thereof, 100 parts by mass of cement, an unsaturated ring, and an unsaturated ring. Each of the ring comprises a polymer of a compound having one or more sulfo groups and / or 0.05 to 20 parts by mass of an organic compound which is a salt thereof.

  Examples of the cement used in the present invention include Portland cement and mixed cement specified by JIS. Specifically, ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, medium heat Portland cement, low heat Portland cement, sulfate-resistant Portland cement, and their low alkali type Portland cement, blast furnace cement, fly ash Examples thereof include cement and silica cement.

  As the formalin condensate of naphthalene sulfonic acid and / or a salt thereof used in the present invention, for example, a formalin condensate of naphthalene sulfonate can be used. The naphthalene sulfonate is a salt with an alkali metal such as sodium (Na) or potassium (K), an alkaline earth metal such as magnesium (Mg) or calcium (Ca), ammonium or an amine. preferable.

  As the formalin condensate of naphthalene sulfonic acid and / or its salt used in the present invention, a formalin condensate of naphthalene sulfonic acid and / or its salt, which is usually used as a high performance dispersant for concrete, should be used. Is preferred.

  As a formalin condensate of naphthalene sulfonic acid and / or its salt, in addition to those used as high-performance dispersants for concrete, they are commercially available as dispersants used in pigments, dyes, and agrochemical wettable powders. Things may be used. Further, the formalin condensate of naphthalene sulfonic acid and / or its salt is the one in which the main component of naphthalene sulfonic acid and / or its salt is the main component, and unreacted monomers remaining during the production of the polymer. Alternatively, it may be a product obtained by removing and purifying unreacted monomers, or a product in which an additive or the like is mixed. 1 type may be used for the formalin condensate of naphthalenesulfonic acid and / or its salt, and it may use 2 or more types together.

  The amount of naphthalene sulfonic acid and / or its salt formalin condensate in the cement composition is 0.3-5 parts by mass, preferably 0.4-4 parts by mass, based on the solid content with respect to 100 parts by mass of cement. More preferably, it is 0.5-3.5 mass parts, More preferably, it is 0.6-3 mass parts. The formalin condensate of naphthalene sulfonic acid and / or its salt is based on the solid content. A compound in which each ring of the unsaturated ring has one or more sulfo groups when the amount of the formalin condensate of naphthalenesulfonic acid and / or a salt thereof is less than 0.3 parts by mass with respect to 100 parts by mass of cement Even if it is used in combination with an organic compound which is a polymer and / or a salt thereof, the effect of improving the sulfuric acid resistance is small, and if it exceeds 5 parts by mass, even if used in combination with the above organic compound, the material separation can be suppressed. There are cases where it is not possible.

The organic compound used in the present invention is a polymer of a compound having an unsaturated ring and each unsaturated ring having one or more sulfo groups (—SO ₃ H) and / or a salt thereof. These have an unsaturated ring, and each ring of the unsaturated ring has a polycondensate of a compound having one or more sulfo groups (—SO ₃ H) and formalin, and / or an unsaturated ring, In addition, a polymer having a compound in which each ring of the unsaturated ring has one or more sulfo groups as a monomer and / or sulfonation of a polymer having an unsaturated ring is produced.

  The organic compound used in the present invention has an unsaturated ring, and the unsaturated ring may be a single ring or a condensed ring. The unsaturated ring may be substituted with an alkyl group having 1 to 4 carbon atoms such as a hydroxy group or a methyl group.

  Further, the unsaturated ring may be a carbocyclic ring or a heterocyclic ring. Examples of the carbocycle include at least one selected from the group consisting of a benzene ring, a naphthalene ring, and an anthracene ring.

  Each ring of the unsaturated ring has one or more sulfo groups. In the case of a single ring, this means that the ring has one or more sulfo groups, and in the case of a condensed ring, a condensed ring. Each ring (nucleus) that forms a ring has one or more sulfo groups. For example, a naphthalene ring refers to a case where two benzene rings (nuclei) each have one or more sulfo groups.

  Examples of the organic compound used in the present invention include a polycondensate of a formalin with a compound having an unsaturated ring and each ring of the unsaturated ring having one or more sulfo groups. Examples of the compound having an unsaturated ring and each unsaturated ring having one or more sulfo groups include phenolsulfonic acid, phenoldisulfonic acid, and naphthalenedisulfonic acid.

  Examples of the organic compound used in the present invention also include a polymer having an unsaturated ring and a monomer having a compound in which each ring of the unsaturated ring has one or more sulfo groups. In this case, it may be a homopolymer having one kind of compound as a monomer or a copolymer having two or more kinds as a monomer. For example, a homopolymer of a compound having an ethylenically unsaturated bond such as styrene sulfonic acid or vinyl naphthalene having a sulfo group substituted on each benzene ring (core), or a copolymer thereof.

  The organic compound used in the present invention may be in the form of a salt, and examples thereof include alkali metal salts such as sodium salts and alkaline earth metal salts such as calcium salts. The organic compounds and salts thereof may be used alone or in combination of two or more.

  As an organic compound used in the present invention, polystyrenesulfonic acid and / or a salt thereof is a homopolymer containing a repeating unit represented by the following formula (1), or a monomer containing a unit represented by the following formula (1). And a copolymer of a monomer having an unsaturated double bond such as styrene or α-methylstyrene and having or not having a sulfo group as a substituent on the benzene ring, acrylonitrile, or methyl methacrylate. May be.

  In the above formula, R and R ′ each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms, and M represents an alkali metal such as hydrogen, lithium, sodium or potassium, or an alkaline earth such as magnesium or calcium. Indicates metal. As the organic compound having a sulfo group used in the present invention, it is preferable to use polystyrene sulfonic acid which is a homopolymer of styrene sulfonic acid.

  The organic compound used in the present invention is preferably a polymer compound, and when the organic compound is polystyrene sulfonic acid, those having a weight average molecular weight of 10,000 to 2,000,000 are preferable, and more preferable. Is from 20,000 to 1,000,000. When the molecular weight is 10,000 or more, sulfuric acid resistance can be secured, and when the molecular weight is 2,000,000 or less, the viscosity does not increase. Here, the weight average molecular weight is a value calculated in terms of a calibration curve of polystyrene sulfonic acid and p-toluenesulfonic acid by a gel filtration chromatography (GFC) method.

  The amount of the organic compound used in the present invention is 0.05 to 20 parts by mass, preferably 0.07 to 10 parts by mass, and more preferably 0.1 to 8 parts by mass with respect to 100 parts by mass of cement. . Especially preferably, it is 0.1-5 mass parts. The amount of the organic compound is based on the solid content. When the amount of the organic compound is less than 0.05 parts by mass with respect to 100 parts by mass of the cement, the effect of improving the sulfuric acid resistance is small even in combination with naphthalenesulfonic acid and / or a formalin condensate thereof, When the amount exceeds 20 parts by mass, not only is the cost disadvantageous, but the fresh properties and curability of the cement composition may be deteriorated.

  When the cement composition of the present invention is used in combination with a formalin condensate of naphthalenesulfonic acid and / or a salt thereof, the amount of the organic compound is preferably 0.05 to 2.0 with respect to 100 parts by mass of cement. The amount may be as small as mass parts, more preferably 0.06-1.0 mass parts, still more preferably 0.07-1.5 mass parts, particularly preferably 0.08-0.6 mass parts. Thus, by using together the said organic compound and the formalin condensate of naphthalenesulfonic acid and / or its salt, the quantity of the said organic compound is 0.05-2.0 mass parts with respect to 100 mass parts of cement. Even in a small amount, material separation of the cement composition can be suppressed, and the sulfuric acid resistance of the cured product can be further improved.

  The cement composition of the present invention is generally used as a high-performance dispersant, a specific amount of a formalin condensate of naphthalenesulfonic acid and / or a salt thereof, and is usually also used as a fluidizing agent. It has been found that the combined use of the specific amount of the organic compound with the specific amount not only improves the fluidity but also has the effect of suppressing unpredictable material separation. It has been found that the sulfuric acid resistance of a cured product containing a product can also be improved.

  Although the mechanism of improving the sulfuric acid resistance of the hardened cement by the present invention is not completely elucidated, the sulfo group following the naphthalene structure of the formalin condensate of naphthalene sulfonic acid and / or its salt, The sulfo group of the compound is adsorbed on gypsum produced by the reaction of sulfuric acid and cement when the cement hardened body is exposed to sulfuric acid, and the crystal growth is controlled efficiently, thereby suppressing the expansibility of gypsum and cement particles A dense gypsum layer is produced on the surface. This gypsum layer prevents erosion of sulfuric acid to suppress further reaction between sulfuric acid and hardened cement, and only a formalin condensate of naphthalene sulfonic acid and / or its salt used as a high-performance dispersant for concrete Therefore, it is estimated that the sulfuric acid resistance which could not be obtained can be further improved.

  The sulfuric acid resistant cement composition of the present invention preferably further contains 30 to 400 parts by mass of limestone fine powder with respect to 100 parts by mass of cement. The limestone fine powder used in the present invention is more preferably 50 to 350 parts by mass, still more preferably 70 to 300 parts by mass, and particularly preferably 80 to 250 parts by mass with respect to 100 parts by mass of cement. . When the amount of fine limestone powder is within the above range, it becomes possible to produce a denser gypsum layer when the cement hardened body made of the cement composition is exposed to sulfuric acid, and the hardened body has a sulfuric acid resistance. The effect which improves further can also be expected.

As the limestone fine powder, one having a brain specific surface area of preferably 2000 to 20000 cm ² / g can be used. Blaine specific surface area of powder limestone fines, more preferably 2500~15000cm ² / g, more preferably 3000~10000cm ² / g, particularly preferably be used those 4000~7000cm ² / g. When the Blaine specific surface area of the limestone fine powder is within the above range, material separation can be suppressed and good workability can be maintained. Here, the Blaine specific surface area of the limestone fine powder is a value measured according to JIS R 5201-1997 “Cement physical test method”.

  The sulfuric acid resistant mortar composition of the present invention further contains fine aggregate in addition to the sulfuric acid resistant cement composition. As the fine aggregate used in the present invention, river sand, land sand, sea sand, crushed sand, blast furnace slag fine aggregate, limestone fine aggregate and the like can be used. The fine aggregate contained in the sulfuric acid resistant mortar composition is preferably 50 to 800 parts by weight, more preferably 100 to 650 parts by weight, and even more preferably 150 to 500 parts by weight, particularly 100 parts by weight of cement. Preferably it is 150-400 mass parts, Most preferably, it is 180-300 mass parts.

  The sulfuric acid resistant concrete composition of the present invention further comprises coarse aggregate in the sulfuric acid resistant mortar composition. As the coarse aggregate used in the present invention, gravel, crushed stone, blast furnace slag coarse aggregate, limestone coarse aggregate and the like can be used. The coarse aggregate is preferably 200 to 320 parts by mass, more preferably 230 to 290 parts by mass, and further preferably 250 to 270 parts by mass with respect to 100 parts by mass of cement. If the blending amount of the coarse aggregate is within the above range, good fresh properties can be obtained.

  The sulfuric acid resistant cement composition of the present invention, and the sulfuric acid resistant mortar composition and the sulfuric acid resistant concrete composition using the same can be premixed prior to kneading. When adding water and kneading, a polymer of a compound having a formalin condensate of naphthalenesulfonic acid and / or a salt thereof, an unsaturated ring, and each unsaturated ring having one or more sulfo groups It is preferable to prepare an organic compound, fine aggregate and other admixtures which are salts thereof. Thus, the sulfuric acid-resistant cement composition or sulfuric acid-resistant mortar composition and sulfuric acid-resistant concrete composition of the present invention can be prepared by a simple method, such as a facility for forming a normal cement hardened body. Can be easily and inexpensively prepared.

  In addition, the sulfate-resistant cement composition of the present invention, and the sulfate-resistant mortar composition and sulfate-resistant concrete composition using the same include base cement, naphthalenesulfonic acid and / or a salt thereof as a basic component. In addition to the condensate, the polymer of a compound having an unsaturated ring and each ring of the unsaturated ring having one or more sulfo groups and / or a salt thereof, limestone fine powder and water, fresh AE agent, AE water reducing agent, high performance water reducing agent, high performance AE water reducing agent, medium performance water reducing agent, high performance water reducing agent which are compounds of lignin type, naphthalene type, polyol type, polycarboxylic acid type, etc. to adjust properties Further, known additives such as chemical admixtures such as multifunctional water reducing agents, thickeners, antifoaming agents, air amount adjusting agents, curing accelerators, curing retarders, and reinforcing rod rust preventives can be added. Paste, mortar As the material of the concrete, it can be used in conventional construction methods. Further, the curing can be produced not only by room temperature curing but also by steam curing or heat curing.

  Furthermore, the cured product obtained by curing any one composition selected from the group consisting of the sulfuric acid resistant cement composition, the sulfuric acid resistant mortar composition, and the sulfuric acid resistant concrete composition of the present invention includes an aqueous solution containing sulfuric acid, A gypsum layer is formed on the surface by contact. In these cured bodies having a gypsum layer on the surface, sulfuric acid erosion is prevented by the gypsum layer, and the sulfuric acid resistance is improved.

  The sulfuric acid resistant cement composition of the present invention, and the sulfuric acid resistant mortar composition and sulfuric acid resistant concrete composition using the same are concrete structures such as hot spring facilities, sewerage facilities, chemical factories, etc. where excellent sulfuric acid resistance is required. It can be suitably used for concrete products using cement such as objects, pipes, U-shaped grooves, and concrete piles. Furthermore, it can be suitably used as an anticorrosion coating material that is applied to the surface of these concrete products to form an anticorrosion coating layer, or as a repair material for a deteriorated part.

  Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. Note that the present invention is not limited to these examples.

[Materials used]
The following materials were used.
(1) Cement (C):
Normal Portland cement: Blaine specific surface area 3270 cm ² / g (measured according to JIS R 5201-1997 “Physical test of cement”. The porosity of the sample bed was 0.50.)
(2) Limestone fine powder Limestone fine powder (LSP): Blaine specific surface area 4500 cm ² / g (measured according to JIS R 5201-1997 “Cement physical test”. The porosity of the sample bed was 0.47. )
(3) Aggregate (i) Fine aggregate Sea sand (S1) (surface dry density: 2.58 g / cm ³ , coarse particle ratio 2.68)
Crushed sand (S2) (surface dry density: 2.65 g / cm ³ , coarse particle ratio 2.71)
(4) Chemical admixture (i) Formalin condensate (NS) of sodium naphthalene sulfonate (solid content: 40% by mass aqueous solution, gel filtration chromatography (calibration curve conversion of polystyrene sulfonic acid and p-toluene sulfonic acid) (Ii) Polystyrene sulfonic acid (PS) (solid content concentration: 20% by mass aqueous solution, Polynas PS-100 (manufactured by Tosoh Corporation), gel filtration chromatography (polystyrene sulfonic acid and p-toluene) Weight average molecular weight 1,000,000) measured by sulfonic acid calibration curve) (iii) Air amount adjusting agent (T) (Micro Air 404 (BASF Pozzolith))
(5) Separation reducing agent TNS-100 (manufactured by Taiheiyo Materials Co., Ltd.) (V1)
Acti-Gel208 (ITC) (V2) (6) Mixing water (W)
Tap water

[Preparation of mortar]
Mortar compositions were prepared according to the mixing method in JIS R 5201-1997 “Physical test of cement” at the blending ratio shown in Table 1. Specifically, a mortar composition was prepared as follows.
Table 1 shows water, chemical admixture (NS and / or PS), separation reducing agent (V1, V2), air amount adjusting agent (T), ordinary Portland cement (C), and fine limestone powder (LSP). Then, the paddle was immediately mixed with a kneader while rotating at a low speed (rotation speed: 140 ± 5 rotations per minute, revolution speed: 62 ± 5 rotations). In addition, in all the mixing | blendings, the air quantity adjusting agent (antifoamer) was mix | blended so that it might be 0.01 mass part with respect to 100 mass parts of water. Thirty seconds after starting the paddle, fine aggregate was added to the kneaded mixture in 30 seconds. Next, the paddle was kneaded for 30 seconds while rotating at high speed (spinning speed: 285 ± 10 rotations per minute, revolution speed: 125 ± 10 rotations). Agitation was then stopped and the mixture was scraped from the paddles and side walls of the kneader for the first 15 seconds after stopping. 90 seconds after the stirring was stopped, the paddle was rotated again at the same high speed as above and kneaded for 60 seconds to obtain a mortar composition. As the kneader, a kneader specified in JIS R 5201-1997 “Cement Physical Test” was used.

[Test method]
(1) Visual observation of zero strike flow and material separation of mortar composition In the method described in JIS R 5201-1997 “Physical test method of cement 11. Flow test” And the presence or absence of separation of the mortar composition were visually confirmed. The case where material separation occurred in the mortar composition was evaluated as x, and the case where material separation did not occur was evaluated as ◯. The results are shown in Table 2.

(2) Sulfuric acid immersion test <Preparation of cured product>
A mortar composition prepared in a mold having a diameter of 5 cm × height of 10 cm was placed, allowed to stand at 20 ± 2 ° C. for 24 hours, heated to 20 ° C./hour to 65 ° C., held for 4 hours, After the temperature was lowered to 20 ° C. at 10 ° C./hour, the product was cured in 20 ± 2 ° C. water until the age of 7 days to obtain a cured mortar, which was used as a test specimen.
<Evaluation of sulfuric acid resistance>
A sulfuric acid resistance test was conducted based on the “JIS chemical test method by immersion in concrete solution”. Specifically, the specimen after curing is immersed in a 5% by mass sulfuric acid aqueous solution (pH of about 0.3, 20 ± 2 ° C.), and the specimen from the aqueous sulfuric acid solution is immersed after 1 week, 2 weeks and 4 weeks of immersion. Was taken out. The removed specimen was washed with water using a brush, the moisture was wiped off with a towel, and the mass was measured. The mass change was calculated | required by the following formula | equation (2). The results are shown in Table 3.
Mass reduction rate (%) = (mass of specimen before being immersed in sulfuric acid aqueous solution−mass of specimen after being immersed in sulfuric acid aqueous solution for a predetermined period) / (mass of specimen before being immersed in sulfuric acid aqueous solution) × 100 ... (2)

[Test results]
(1) Zero strike flow and material separation of mortar composition As shown in Table 2, the mortar compositions of Examples 1 to 3 have a zero freshness flow of 109 to 203 mm and have good fresh properties. Was confirmed. In addition, no material separation occurred. On the other hand, in Comparative Example 1, the zero-stroke flow of mortar exceeded 300 mm, and material separation occurred. In Comparative Example 2 in which the separation reducing agent was added, no material separation occurred.

(2) Sulfuric acid resistance of the cured product As shown in Table 3, when Comparative Example 2 and Examples 1 to 3 containing the same amount of formalin condensate of naphthalene sulfonic acid and / or its salt were compared, polystyrene sulfonic acid was found to be In Examples 1 to 3 included, the mass reduction rate was smaller than that of Comparative Example 2, and it was confirmed that the sulfuric acid resistance was improved. As shown in Examples 1 to 3, as the amount of polystyrene sulfonic acid increased, the mass reduction rate for the immersion period of 2 weeks and 4 weeks was reduced, and it was confirmed that the sulfuric acid resistance was improved. .

  The specimens of Examples 1 to 3 all had a white surface, and it was confirmed that a dense gypsum layer was formed on the surface by contacting with the sulfuric acid aqueous solution. It can be inferred that sulfuric acid erosion of concrete is prevented by this gypsum layer.

  The sulfuric acid resistant cement composition of the present invention, and the sulfuric acid resistant mortar composition and sulfuric acid resistant concrete composition using the same are likely to be exposed to sulfuric acid or sulfate in hot springs, sewer facilities, chemical factories, etc. It is not only applicable to concrete structures and concrete products used in high places, but also has high durability against acid rain, which has become a problem in recent years, so it is useful as a composition for forming general concrete products. high.

Claims (7)

Used at a pH of 2 or less exposed to sulfuric acid or sulfate,
Polystyrene sulfonic acid alkali metal having a weight average molecular weight of 10,000 to 2,000,000 and a formalin condensate of naphthalenic sulfonic acid and / or a salt thereof 1.9 to 5 parts by mass with respect to 100 parts by mass of cement A sulfate-resistant cement composition comprising 0.13 to 20 parts by mass of a salt polymer . The present invention comprises 1.9 to 5 parts by mass of a formalin condensate of naphthalene sulfonic acid and / or a salt thereof and 0.52 to 20 parts by mass of a polymer of an alkali metal salt of polystyrene sulfonic acid with respect to 100 parts by mass of cement. The sulfuric acid resistant cement composition according to 1 . The sulfuric acid resistant cement composition according to claim 1 or 2, wherein the polymer of the alkali metal salt of polystyrene sulfonic acid is a polymer of sodium polystyrene sulfonate. The sulfate-resistant cement composition according to any one of claims 1 to 3, comprising 30 to 400 parts by mass of limestone fine powder with respect to 100 parts by mass of cement. The sulfuric acid cement composition according to any one of claims 1-4, further comprising a fine aggregate, sulfuric acid mortar composition. The sulfuric acid resistant mortar composition according to claim 5 , further comprising a coarse aggregate. Any one selected from the group consisting of the sulfuric acid resistant cement composition according to any one of claims 1 to 4 , the sulfuric acid resistant mortar composition according to claim 5 , and the sulfuric acid resistant concrete composition according to claim 6 . A sulfate-resistant cured body, which is obtained by curing one composition and has a gypsum layer formed on the surface by contacting with an aqueous solution containing sulfuric acid.