JP2006327866A - Cement composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement composition excellent in antibacterial properties, acid resistance, and strength development. <P>SOLUTION: The cement composition contains calcium aluminate compounds, fine powder of granulated blast furnace slag, and a silver-based antibacterial agent and/or a copper-based antibacterial agent. Preferably, the content of the antibacterial agent is 1-10 parts in 100 parts of the cement composition. Addition of a polymer for cement to the cement composition improves the bonding strength, and that of a fibrous substance improves the cracking resistance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention mainly relates to a cement composition used for a concrete structure in the field of civil engineering and architecture.

In the present invention, “parts” and “%” are based on mass unless otherwise specified.
Moreover, the cement concrete said by this invention is a general term for cement paste, mortar, and concrete.

Conventionally, as a substance having antibacterial and antifungal properties, a powder of calcined colemanite obtained by calcining colemanite 2CaO · 3B ₂ O ₃ · 5H ₂ O has been known (see Patent Document 1), and this powder is mixed with cement. Therefore, it is known that antibacterial and antifungal properties can be imparted to the hardened cement body. However, calcined colemanite contains a boric acid component that significantly delays the setting of cement as a main component, and therefore causes poor curing when mixed in a large amount.

  In recent years, the number of cases of deterioration of concrete structures due to sulfuric acid has been increasing, mainly in sewage treatment facilities, and more studies on sulfuric acid deterioration of concrete have been seen. The cause of the generation of sulfuric acid in sewage treatment facilities is known to be due to the activity of microorganisms. In addition to using acid-resistant materials as a countermeasure against acid degradation, the application of antibacterial agents is being studied.

  As acid-resistant materials, mortar and concrete in which a large amount of blast furnace slag, fly ash, silica fume and the like are mixed with Portland cement (see Patent Document 2), and mortar and concrete using alumina cement have been proposed (Patent Document 3). , See Patent Document 4).

JP 2002-20210 A JP 2000-128618 A JP-A-60-180945 JP-A-1-141844

  The present invention provides a cement composition having excellent antibacterial properties, acid resistance and strength development.

  That is, the present invention provides (1) a cement composition comprising a calcium aluminate compound, blast furnace granulated slag fine powder, a silver antibacterial agent and / or a copper antibacterial agent, and (2) an antibacterial agent. (1) Cement composition which is 1-10 parts in 100 parts of cement composition, (3) Cement composition of (1) or (2) which contains polymer for cement, (4) Fiber The cement composition according to any one of (1) to (3), which contains a quality substance.

  The cement composition of the present invention has excellent antibacterial properties, acid resistance and strength development.

The calcium aluminate compound of the present invention is a generic term for compounds mainly composed of CaO and Al ₂ O ₃ and is not particularly limited. Specific _{examples, CaO · 2Al 2 O 3,} CaO · Al 2 O 3, 12CaO · 7Al 2 O 3, 11CaO · 7Al 2 O 3 · CaF 2, 3CaO · Al 2 O 3, 3CaO · 3Al 2 O 3 -Crystalline calcium aluminates represented as CaSO _{4 and the} like, and amorphous compounds mainly composed of CaO and Al ₂ O ₃ components. Among these, it is preferable from the viewpoint of securing the pot life to select one having a CaO / Al ₂ O ₃ molar ratio of 1 to 2. Moreover, it is preferable from an acid-resistant viewpoint.

Examples of a method for obtaining a calcium aluminate compound include a method in which a CaO raw material and an Al ₂ O ₃ raw material are heat-treated with a rotary kiln or an electric furnace. Examples of the CaO raw material for producing the calcium aluminate compound include calcium carbonate such as limestone and shells, calcium hydroxide such as slaked lime, and calcium oxide such as quick lime. Examples of the Al ₂ O ₃ raw material include aluminum by-products in addition to industrial by-products called bauxite and aluminum residue ash.

When a calcium aluminate compound is obtained industrially, impurities may be contained. Specific examples thereof include SiO ₂ , Fe ₂ O ₃ , MgO, TiO ₂ , MnO, Na ₂ O, K ₂ O, Li ₂ O, S, P ₂ O ₅ , and F. The presence of these impurities is not particularly problematic as long as the object of the present invention is not substantially impaired. Specifically, there is no particular problem if the total of these impurities is in the range of 10% or less.

Further, as the impurity compounds, calcium alumino ferrite etc. _{4CaO · Al 2 O 3 · Fe} 2 O 3, 6CaO · 2Al 2 O 3 · Fe 2 O 3, 6CaO · Al 2 O 3 · 2Fe 2 O 3, 2CaO · Calcium ferrites such as Fe ₂ O ₃ and CaO · Fe ₂ O ₃ , galenite 2CaO · Al ₂ O ₃ · SiO ₂ , calcium aluminosilicates such as anorthite CaO · Al ₂ O ₃ · 2SiO ₂ , melvinite 3CaO · MgO · 2SiO _2, Akerumanaito 2CaO · MgO · 2SiO _2, calcium magnesium silicate, such as Monte celite CaO · MgO · SiO _2, tri-calcium silicate 3CaO · SiO _2, dicalcium silicate 2CaO · SiO _2, rankinite night 3CaO · 2 in some cases iO _2, calcium silicates, such as wollastonite CaO · SiO _2, calcium titanate CaO · TiO _2, free lime, leucite _{(K 2 O, Na 2 O} ) , etc. · _{Al 2} O 3 · SiO 2 . In the present invention, these crystalline or amorphous materials may be mixed.

The particle size of the calcium aluminate compound of the present invention is not particularly limited, but is usually in the range of 3000 to 9000 cm ² / g in terms of Blaine specific surface area, more preferably about 4000 to 8000 cm ² / g. . If it is less than 3000 cm ² / g, strength development may not be sufficient, and if it exceeds 9000 cm ² / g, handling may be difficult.

The ground granulated blast furnace slag of the present invention bears the effect of preventing strength reduction due to conversion of calcium aluminate compounds and acid resistance. The fineness of the granulated blast furnace slag powder is not particularly limited, but is usually in the range of about 3000 to 9000 cm ² / g in terms of the specific surface area of Blaine.

In the present invention, pozzolanes can be used in addition to latent hydraulic materials such as ground granulated blast furnace slag. Pozzolana plays a role of promoting the effect of preventing the strength reduction due to the conversion of the calcium aluminate compound and the effect of improving the acid resistance. The pozzolan is not particularly limited, and examples include fly ash, silica fume, pulp sludge incineration ash, sewage sludge incineration ash, and waste glass powder. Among these, use of fly ash or silica fume is preferable.
The fineness of fly ash and silica fume is not particularly limited. Usually, fly ash has a brain specific surface area of about 3000 to 9000 cm ² / g, and silica fume has a BET specific surface area of 2 It is in the range of about ~ 200,000 m ² / g.

  The blending ratio of each material in the cement composition of the present invention is not particularly limited, but usually in 100 parts of a binder composed of calcium aluminate compound and ground granulated blast furnace slag, calcium aluminate compound. 30 to 80 parts are preferable, and 40 to 70 parts are more preferable. The ground granulated blast furnace slag powder is preferably 20 to 70 parts, more preferably 30 to 60 parts. Moreover, pozzolana can be used by substituting with a part of ground granulated blast furnace slag as needed. If the calcium aluminate compound is less than 30 parts, or if the granulated blast furnace slag powder exceeds 70 parts, strength development may not be sufficient, the calcium aluminate compound may exceed 80 parts, If the granulated slag fine powder is less than 20 parts, strength reduction due to conversion may occur or sufficient acid resistance may not be obtained.

  The antibacterial agent of the present invention is a silver-based and / or copper-based antibacterial agent. Examples of such antibacterial agents include those in which silver or copper is supported on zeolite or bentonite, those in which silver or copper is supported on apatite, or glassy substances containing silver or copper. Among these, zeolite-based ones are preferable from the viewpoint of improving antibacterial properties when applied to the cement composition of the present invention. As the zeolite-based antibacterial agent, for example, trade name “ZEOMITY” manufactured by Sinanen Zeomic Co., Ltd. can be used.

  The amount of the antibacterial agent used is not particularly limited, but is preferably 1 to 10 parts in 100 parts of a cement composition composed of a binder composed of a calcium aluminate compound and ground granulated blast furnace slag and an antibacterial agent. 3 to 7 parts are more preferable. If it is less than 1 part, the antibacterial property is not sufficient, and if it exceeds 10 parts, further improvement of the effect cannot be expected.

  Examples of the polymer for cement of the present invention (hereinafter referred to as polymer) include, but are not particularly limited to, an aqueous polymer dispersion, a re-emulsifying powder resin, a water-soluble polymer, and a liquid polymer. Examples of aqueous polymer dispersions include natural rubber latex, acrylic rubber, styrene / butadiene rubber (SBR), chloroprene rubber (CR), and other synthetic rubber latex, ethylene / vinyl acetate copolymer (EVA), and polyacrylic acid ester (PAE). ) And the like. Examples of the polymer form include a re-emulsified powder type and a liquid type. These are used for improving adhesion between mortar and existing concrete and improving durability.

  The amount of the polymer used is preferably 1 to 15 parts in terms of solid content, preferably 3 to 10 parts per 100 parts of a cement composition consisting of a binder composed of calcium aluminate compound and ground granulated blast furnace slag and an antibacterial agent. Part is more preferred. If it is less than 1 part, improvement of adhesion properties with existing concrete or the like may not be expected, and if it exceeds 15 parts, improvement of the effect cannot be expected and it is not economical.

  The mixing method of the polymer is not particularly limited, but in the case of powder, it may be mixed with cement in advance or simultaneously charged with other materials at the time of kneading, or suspended or dissolved in water. In the case of a liquid, there are a method of using it simultaneously with other materials at the time of kneading or mixing with water.

  The fibrous substance of the present invention is used for improving the toughness of mortar and preventing the mortar from being cracked or dropped due to peeling off, and any inorganic or organic fiber can be used. Examples of inorganic fibers include glass fibers, carbon fibers, rock wool, asbestos, ceramic fibers, and metal fibers. Organic fibers include vinylon fibers, polyethylene fibers, polypropylene fibers, polyacrylic fibers, cellulose fibers, Examples thereof include polyvinyl alcohol fiber, aramid fiber, pulp, hemp, wood wool, and wood chip. Among these, vinylon fiber and polypropylene fiber are preferable in terms of mixing property, workability, durability, impact resistance, and economy.

  The length of the fiber is preferably 20 mm or less, more preferably 6 to 12 mm, in terms of mixing properties and workability. If it exceeds 20 mm, the appearance of the mortar surface may deteriorate.

  The amount of the fibrous substance used is preferably 3 parts by weight or less, more preferably 1.5 parts by weight or less, in 100 parts by weight of mortar composed of a binder, an antibacterial agent, a polymer, fine aggregate and water. If it is less than 0.5 parts by weight, the crack resistance is not improved, and if it exceeds 3 parts by weight, problems may occur in mortar kneading.

The particle size of the cement composition of the present invention is not particularly limited since it depends on the purpose and application to be used, usually, preferably 3000~8000cm ² / g in Blaine specific surface area, 4000~6000cm ² / g is More preferred. If it is less than 3000 cm ² / g, sufficient strength development may not be obtained, and if it exceeds 8000 cm ² / g, workability may deteriorate.

  In this invention, you may use together well-known cement other than the cement composition of this invention. As well-known cements, various portland cements such as normal, early strength, ultra-early strength, low heat, and moderate heat, various mixed cements obtained by mixing blast furnace slag, fly ash, or silica with these portland cements, and limestone powder And filler cement mixed with blast furnace slow-cooled slag fine powder, waste-use type cement, so-called eco-cement, etc., and one or more of these can be used in combination.

  In the present invention, in addition to aggregates such as sand and gravel, limestone fine powder, blast furnace slow-cooled slag fine powder, sewage sludge incinerated ash and its molten slag, municipal waste incinerated ash and its molten slag, pulp sludge incinerated ash, etc. Admixtures, water reducing agents, AE water reducing agents, high performance water reducing agents, high performance AE water reducing agents, antifoaming agents, thickeners, rust preventives, antifreezing agents, shrinkage reducing agents, polymers, setting modifiers, clays such as bentonite One or more of minerals and anion exchangers such as hydrotalcite can be used as long as the object of the present invention is not substantially inhibited.

In the present invention, the mixing method of each material is not particularly limited, and the respective materials may be mixed at the time of construction, or a part or all of them may be mixed in advance.
Any existing device can be used as the mixing device, and for example, a tilting barrel mixer, an omni mixer, a Henschel mixer, a V-type mixer, and a Nauta mixer can be used.

  Hereinafter, although an Example demonstrates in detail, it is not limited to this.

  A calcium aluminate compound and ground granulated blast furnace slag were blended as shown in Table 1 to form a binder, and 95 parts of this binder was blended with 5 parts of an antibacterial agent to prepare a cement composition. Subsequently, mortar was prepared according to JIS R 5201, and the reduction rate of compressive strength by the accelerated conversion test, and antibacterial properties and acid resistance were evaluated. For comparison, the same procedure was performed when ordinary Portland cement was used instead of the calcium aluminate compound. The results are also shown in Table 1.

<Materials used>
Calcium aluminate compound (1): Commercially available alumina cement, manufactured by Denki Kagaku Kogyo Co., Ltd., and CaO.Al ₂ O ₃ as a main component. Blaine specific surface area 5000 cm ² / g.
Calcium aluminate compound (2): 12CaO.7Al ₂ O ₃ , reagent grade calcium carbonate and aluminum oxide are mixed at a molar ratio of 12 to 7 and baked at 1350 ° C. for 3 hours twice. And synthesized. Blaine specific surface area 5000 cm ² / g.
Calcium aluminate compound (3): Amorphous 12CaO · 7Al ₂ O ₃ , 3% reagent grade silica added to calcium aluminate compound (2), melted at 1650 ° C., and then rapidly cooled to synthesize . Blaine specific surface area 5000 cm ² / g.
Calcium aluminate compound (4): An equal mixture of calcium aluminate compound (1) and calcium aluminate compound (2). Blaine specific surface area 5000 cm ² / g.
Blast furnace granulated slag fine powder: manufactured by Kanto Sement Co., Ltd., trade name “ESMENT”, Blaine specific surface area 4000 cm ² / g.
Ordinary Portland cement: A mixture of 3 types of commercial products.
Antibacterial agent (1): manufactured by Sinanen Zeomic Co., Ltd., trade name “Zeomity”, a zeolite antibacterial agent carrying silver and copper.
Water: Tap water fine aggregate: Standard sand used in JIS R 5201.

<Measurement method>
Compressive strength: A molded body of 4 cm × 4 cm × 16 cm was prepared by filling mortar into a mold, and the compressive strength at a material age of 28 days was measured according to JIS R5201.
Accelerated conversion test: A specimen subjected to 20 ° C. water curing until the age of 28 days was placed in 50 ° C. warm water for 28 days for accelerated conversion. The evaluation was expressed in terms of strength ratio (%) after the acceleration conversion to the compression strength before the acceleration conversion.
Evaluation of antibacterial properties: A mortar cured body having a length of 30 cm, a width of 30 cm, and a height of 3 cm was prepared, and the surface was neutralized by carbonation for 7 days under the conditions of 30 ° C., carbon dioxide concentration 5%, and relative humidity 60%. A spore suspension of mold species A (Cladosporium cladosporieudes) and mold species B (Aspergillus niger) was applied to the surface of the cured mortar, and the mold resistance test was applied to JIS Z 2911 for 4 weeks. According to the same procedure. In the evaluation of mold resistance, mold was generated in an area where x was over 1/3, mold was generated in an area where Δ was 1/3 or less, and o was not generated.
Acid resistance evaluation: The specimen was immersed in a 5% strength sulfuric acid solution for 3 months, and the acid resistance was evaluated from the change in the appearance of the specimen and the decrease in mass. As for the evaluation criteria, × indicates that the appearance change is remarkable and the mass change rate is ± 5% or more, and Δ indicates that the appearance change is significant or the mass change rate is ± 5% or more. In the case, ◯ indicates that neither the change in appearance nor the change in mass meets the above conditions.

  From Table 1, it can be seen that the cement composition of the present invention has good strength development and excellent antibacterial properties and acid resistance.

  50 parts of calcium aluminate compound (1) and 50 parts of ground granulated blast furnace slag powder are combined to form a binder. As shown in Table 2, antibacterial activity is shown in Table 2 in 100 parts of a cement composition comprising this binder and an antibacterial agent. Mortar was prepared in the same manner as in Example 1 except that the agent was blended, and antibacterial properties and acid resistance were evaluated. The results are also shown in Table 2.

<Materials used>
Antibacterial agent (1): manufactured by Sinanen Zeomic Co., Ltd., trade name “Zeomity”, a zeolite antibacterial agent carrying silver and copper.
Antibacterial agent (2): Commercially available copper zeolite, average particle size 0.1 mm.
Antibacterial agent (3): Commercially available silver carbonate, average particle size 0.1 mm.
Antibacterial agent (4): commercially available thiabentazole, organic drug.

  From Table 2, it can be seen that the cement composition of the present invention is excellent in antibacterial properties and acid resistance.

  50 parts of calcium aluminate compound (1) and 50 parts of granulated blast furnace granulated slag are blended to form a binder, and 5 parts of the antibacterial agent (1) is contained in 100 parts of the cement composition composed of the binder and the antibacterial agent. Further, the polymer was blended in terms of solid content as shown in Table 3 with respect to 100 parts of the cement composition. The fine aggregate is blended so that the ratio (mass ratio) of fine aggregate is 100: 175 with respect to the cement composition blended with this polymer, and the water / cement composition ratio is 45%. The same operation as in Example 1 was conducted except that water was mixed to prepare a mortar. Further, an adhesion strength test was performed. The results are also shown in Table 3.

<Materials used>
Polymer A: Commercially available acrylic rubber polymer B: Commercially available styrene-butadiene rubber polymer C: Commercially available polyacrylic ester, re-emulsified powder type

<Measurement method>
Adhesion test: Measured according to JIS A 1171.

  From Table 3, it can be seen that the cement composition of the present invention improves the adhesion strength when blended with a polymer and is excellent in antibacterial properties and acid resistance.

  50 parts of calcium aluminate compound (1) and 50 parts of granulated blast furnace granulated slag are blended to form a binder, and 5 parts of the antibacterial agent (1) is contained in 100 parts of the cement composition composed of the binder and the antibacterial agent. Further, 5 parts of polymer A in terms of solid content is blended with 100 parts of this cement composition, and a fibrous material is blended as shown in Table 4 (binding material, antibacterial agent, polymer, fine aggregate, This was carried out in the same manner as in Example 3 except that 100 parts by weight of mortar made of water was used and the cracking resistance was confirmed. The results are also shown in Table 4.

<Materials used>
Fibrous material A: Commercially available vinylon fiber, fiber length 6 mm, fiber diameter 0.2 mm
Fibrous material B: Commercially available metal fiber, fiber length 6 mm, fiber diameter 0.2 mm

<Measurement method>
Crack resistance: A mortar was applied to a 50 cm × 50 cm concrete plate with a thickness of 10 mm and left for 1 day in an environment at a temperature of 20 ° C. and a relative humidity of 40%, and the occurrence of cracks was observed. The evaluation criteria were as follows: ○ was not cracked at all, Δ was only one crack, and a plurality of × cracks were generated.

  From Table 4, it can be seen that the cement composition of the present invention has improved crack resistance and excellent antibacterial and acid resistance when a fibrous material is blended.

  The cement composition of the present invention is used in the civil engineering and construction fields such as sewage treatment facilities where antibacterial properties, acid resistance and strength development are required.

Claims (4)

A cement composition comprising a calcium aluminate-based compound, ground granulated blast furnace slag, and a silver-based antibacterial agent and / or a copper-based antibacterial agent. The cement composition according to claim 1, wherein the content of the antibacterial agent is 1 to 10 parts in 100 parts of the cement composition. The cement composition according to claim 1, further comprising a cement polymer. The cement composition according to any one of claims 1 to 3, comprising a fibrous substance.