JP6667333B2 - Cement composition, cement kneaded material - Google Patents

Description

  The present invention relates to a cement composition which is kneaded with water to form a cured product, and a cement kneaded product obtained by kneading the cement composition with water.

  When forming a hardened body by kneading and hardening a cement composition containing cement and water, a kneaded product of the cement composition and water is poured into a mold, or the kneaded product is formed into an existing structure. It may be poured into gaps between objects. For this reason, such a kneaded material is required to have good fluidity.

  As a method of imparting good fluidity to the kneaded material, a method of setting a relatively large amount of water to be kneaded with the cement composition (hereinafter also referred to as kneading water) can be considered. However, in such a method, since a relatively large amount of water remains in the formed cured body, fine voids are generated in the cured body after the cured body is dried. When such voids are formed in the cured body, it becomes a factor for reducing the strength and durability of the cured body. Therefore, AE water reducing agents and high-performance AE water reducing agents are widely used as admixtures that can impart fluidity to a kneaded material without setting a relatively large amount of kneading water (see Patent Document 1). ).

JP 2004-2080 A

  However, it is known that an AE water reducing agent is difficult to obtain a desired fluidity when it is contained in a cement composition containing a large amount of cement or a cement composition containing a large amount of fly ash or blast furnace slag. . Further, the high-performance AE water reducing agent can give the kneaded material superior fluidity than the AE water reducing agent, but is generally more expensive than the AE water reducing agent. When used, it becomes a factor of increasing the production cost of the cement composition and the cured product.

  Therefore, the present invention provides a cement composition capable of imparting better fluidity to a kneaded material even when an AE water reducing agent is used, and a cement kneaded material having better fluidity. The task is to provide

  The cement composition according to the present invention is a cement composition that contains cement, and is kneaded with water to form a hardened body when hardened, and is 0.5% by mass or more to 2.4% by mass of cement. It is characterized by containing not more than 2% by mass of potassium sulfate and not more than 0.2% by mass and not more than 2.0% by mass of the AE water reducing agent based on the mass of the cement.

  According to such a configuration, 0.5% by mass or more and 2.4% by mass or less of potassium sulfate and 0.2% by mass or more and 2.0% by mass or less of AE with respect to the mass of cement are used. By kneading a cement composition containing a water reducing agent and water to form a kneaded product, even when an AE water reducing agent is used, better fluidity can be imparted to the kneaded material. .

  The content of the potassium sulfate is preferably from 1.0% by mass to 2.0% by mass with respect to the mass of the cement.

  According to such a configuration, the content of the potassium sulfate is not less than 1.0% by mass and not more than 2.0% by mass with respect to the mass of the cement, so that even when the AE water reducing agent is used, Further, good fluidity can be imparted to the kneaded material.

  The cement kneaded material according to the present invention is a cement kneaded material obtained by kneading a cement composition containing cement and water, and has a mass of 0.5% by mass or more and 2.4% by mass or less based on the mass of the cement. It is characterized by containing potassium sulfate and 0.2% by mass or more and 2.0% by mass or less of an AE water reducing agent based on the mass of cement.

  According to such a configuration, 0.5% by mass or more and 2.4% by mass or less of potassium sulfate and 0.2% by mass or more and 2.0% by mass or less of AE with respect to the mass of cement are used. By containing the water reducing agent, even when the AE water reducing agent is contained, the cement kneaded material can obtain better fluidity.

  As described above, according to the present invention, even when the AE water reducing agent is used, more favorable fluidity can be imparted to the kneaded material.

  Hereinafter, embodiments of the present invention will be described.

  The cement composition according to the present invention forms a hardened body by being kneaded with water and hardening. Further, the cement composition contains cement, potassium sulfate, and an AE water reducing agent.

  The cement is not particularly limited, and includes, for example, Portland cement such as ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, moderate heat Portland cement, sulfate-resistant Portland cement, white Portland cement, and the like. At least one of mixed cement such as blast furnace cement, fly ash cement, silica cement, and the like, and fast-setting cement (for example, ultra-fast-setting cement, alumina cement, and the like) can be used. In addition, the quick-setting cement refers to a kneading product of water and powder having a water / powder mass ratio of 22%, a setting time of setting of 1 to 60 measured according to “Physical Testing Method of Cement (JIS R5201)”. Minute cement.

  The content of cement in the cement composition is not particularly limited, and is, for example, preferably from 10.0% by mass to 70.0% by mass, and more preferably from 10.0% by mass to 30.0% by mass. % Is more preferable.

  The content of potassium sulfate in the cement composition is from 0.5% by mass to 2.4% by mass, and preferably from 1.0% by mass to 2.0% by mass, based on the mass of the cement. . Further, the content of potassium sulfate in the cement composition is preferably 25.0% by mass to 1000.0% by mass, and more preferably 100.0% by mass to 800.0% by mass, based on the mass of the AE water reducing agent. % Is more preferable.

  The content of the AE water reducing agent in the cement composition is from 0.2% by mass to 2.0% by mass with respect to the mass of the cement, and from 0.2% by mass to 2.0% by mass with respect to the mass of the cement. % Or less, more preferably 0.25% by mass or more and 1.0% by mass or less. Further, the content of the AE water reducing agent in the cement composition is preferably 10% by mass or more and 40.0% by mass or less with respect to the mass of potassium sulfate, and is preferably 12.5% by mass or more and 100.0% by mass or less. Is more preferable.

  The AE water reducing agent is a chemical admixture specified in JIS A 6204, which is classified as an AE water reducing agent. The components of the AE water reducing agent are not particularly limited, and include, for example, lignin sulfonic acid salt, a mixture of a lignin sulfonic acid compound and a water-soluble polymer, lignin sulfonic acid compounds, special polymer surfactants , Organic acid derivatives, mixtures of organic acid derivatives and aromatic high molecular compounds, water-soluble copolymers, mixtures of modified polyols and special surfactants, complexes of lignin sulfonic acid compounds and polyols, highly modified polyol complexes Body, modified lignin sulfonic acid compound, complex of modified lignin sulfonic acid compound and cellulose ether, mixture of lignin sulfonate and oxycarboxylate, oxycarboxylate, lignin sulfonate and polycarboxylic acid compound A mixture of a hydroxy-based complex and a natural resinate, a hydroxy-based complex and Mixture of Guninsuruhon acid derivative, a mixture of lignosulfonate and cellulose ether-based compound, a mixture of modified lignin sulfonate and cellulose ether based compounds.

  The cement composition as described above may contain coarse aggregate or fine aggregate. For example, the cement composition may be a concrete composition containing cement, coarse aggregate and fine aggregate, or a mortar composition containing cement and fine aggregate.

  The coarse aggregate and the fine aggregate are not particularly limited, and for example, it is preferable to use the aggregate described in JIS A 5308 Appendix A for ready-mixed concrete aggregate.

  The coarse aggregate is not particularly limited, and includes, for example, crushed stone, gravel (river gravel), natural lightweight coarse aggregate (perlite, hill stone, etc.), by-product lightweight coarse aggregate, artificial lightweight coarse aggregate, At least one of recycled aggregate and the like can be used.

  The fine aggregate is not particularly limited. For example, natural fine aggregates such as river sand, mountain sand, sea sand, and natural lightweight fine aggregates (such as perlite and hill stone), crushed sand, and artificial lightweight fine aggregates At least one of artificial fine aggregate such as blast furnace slag fine aggregate and by-product lightweight fine aggregate can be used.

  Further, the cement composition according to the present invention may contain an admixture. As the admixture, for example, fly ash, silica fume, cement kiln dust, blast furnace fume, blast furnace granulated slag fine powder, blast furnace decooled slag fine powder, converter slag fine powder, hemihydrate gypsum, expanding material, limestone fine powder, Quicklime fine powder, dolomite fine powder, sodium bentonite, calcium bentonite, attapulgite, sepiolite, activated clay, acid clay, allophane, imogolite, shirasu (volcanic ash), shirasu balloon, kaolinite, metakaolin (calcined clay), synthetic zeolite, Examples include artificial zeolite, artificial zeolite, mordenite, clinoptilolite, and the like. These can be used alone or in combination of two or more.

  Further, the cement composition according to the present invention may contain an admixture. Examples of the admixture include an AE agent, a fluidizing agent, a separation reducing agent, a setting retarder, a setting accelerator, a quick setting agent, a shrinkage reducing agent, a foaming agent, a foaming agent, and a waterproofing agent. These can be used alone or in combination of two or more. In particular, it is preferable that the AE agent is contained in the cement composition. The content of the AE agent is not particularly limited, and is, for example, preferably from 0.0005% by mass to 0.030% by mass, and more preferably from 0.001% by mass to 0. It is more preferably at most 010% by mass. Further, the content of the AE agent in the cement composition is preferably from 0.025% by mass to 15% by mass, and more preferably from 0.1% by mass to 4.0% by mass, based on the mass of the AE water reducing agent. Is more preferable. The cement composition according to the present invention preferably does not contain a high-performance AE water reducing agent. The high-performance AE water reducing agent is a chemical admixture specified in JIS A 6204, which is classified as a high-performance AE water reducing agent.

  The cement composition configured as described above is kneaded with water to form a cement kneaded product. The blending amount of water is not particularly limited. For example, the ratio of water to cement (W / C) in the cement composition is preferably 0.4 or more and 0.6 or less. Then, such a cement kneaded material is poured into a gap between a mold and an existing structure and is cured to form a cured body.

  The cement kneaded material according to the present invention is obtained by kneading a cement composition containing cement and water.

  The content of cement in the cement kneaded material is not particularly limited, and is, for example, preferably from 10.0% by mass to 70.0% by mass, and more preferably from 10.0% by mass to 30.0% by mass. % Is more preferable.

  The content of potassium sulfate in the cement kneaded material is 0.5% by mass or more and 2.4% by mass or less, and preferably 1.0% by mass or more and 2.0% by mass or less based on the mass of the cement. . Further, the content of potassium sulfate in the cement kneaded material is preferably from 25.0% by mass to 1000.0% by mass, and more preferably from 100.0% by mass to 800.0% by mass, based on the mass of the AE water reducing agent. % Is more preferable.

  The content of the AE water reducing agent in the cement kneaded material is from 0.2% by mass to 2.0% by mass with respect to the mass of the cement, and from 0.2% by mass to 2.0% by mass with respect to the mass of the cement. % Or less, more preferably 0.25% by mass or more and 1.0% by mass or less. Further, the content of the AE water reducing agent in the cement kneaded material is preferably 10.0% by mass or more and 400.0% by mass or less with respect to the mass of potassium sulfate, and is preferably 12.5% by mass or more and 100.0% by mass. % Is more preferable.

  The above cement kneaded material may be formed by kneading a cement composition containing potassium sulfate and / or an AE water reducing agent with water, and a cement composition and a potassium sulfate and / or AE water reducing agent (that is, cement). It may be formed by kneading the composition with another potassium sulfate and / or AE water reducing agent) and water.

  As described above, according to the cement composition and the cement kneaded material according to the present invention, even when the AE water reducing agent is used, more favorable fluidity can be imparted to the kneaded material.

  That is, contains 0.5% by mass or more and 2.4% by mass or less of potassium sulfate based on the mass of cement and 0.2% by mass or more and 2.0% by mass or less of the AE water reducing agent based on the mass of cement. By kneading the cement composition to be mixed with water to form a kneaded product, even if an AE water reducing agent is used, more favorable fluidity can be imparted to the kneaded product.

  Further, the content of the potassium sulfate is not less than 1.0% by mass and not more than 2.0% by mass with respect to the mass of the cement, so that even when the AE water reducing agent is used, more favorable fluidity is obtained. Can be imparted to the kneaded material.

  Further, it contains 0.5% by mass or more and 2.4% by mass or less of potassium sulfate based on the mass of the cement and 0.2% by mass or more and 2.0% by mass or less of the AE water reducing agent based on the mass of the cement. By doing so, even when the cement kneaded material contains an AE water reducing agent, better fluidity can be obtained.

  The shrinkage reducing agent and the cement composition according to the present invention are not limited to the above embodiment, and various changes can be made without departing from the gist of the present invention. Further, the configurations and methods of the above-described embodiments may be arbitrarily adopted and combined. Of course, configurations and methods according to various modifications may be arbitrarily selected and employed in the configurations and methods according to the above-described embodiments.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

= Material used =
・ Blast furnace cement type B (BB): Stipulated in JIS R 5211 (Sumitomo Osaka Cement Co., Ltd.)
-Fly ash cement type B (FB): specified in JIS R 5213 (Made by Ube Mitsubishi)
-Early Portland Cement (HC): specified in JIS R 5210 (Sumitomo Osaka Cement Co., Ltd.)
・ Water: tap water ・ Fine aggregate: mountain sand ・ Coarse aggregate: sandstone crushed stone ・ Fly ash (FA): Fly ash II (from Tohoku Electric Power Noshiro Thermal Power Station)
Potassium sulfate _(K 2 _SO 4): Reagent (manufactured by Otsuka Chemical Co., Ltd.)
AE water reducing agent (No. 70): Master Pozzolis No. 70 70 (main component: complex of lignin sulfonic acid compound and polyol, manufactured by BASF Japan)
・ AE water reducing agent (NC): Plastcrete 20N (main components: modified polyol and special surfactant, manufactured by Sika Japan)
AE water reducing agent (S): Floric S (main component: lignin sulfonate and oxycarboxylate, manufactured by Floric)
・ High-performance AE water reducing agent (SP): Masterglenium SP8SV (main component: polycarboxylic acid ether compound, manufactured by BASF Japan)

<Slump and air volume measurement>
In Examples 2, 3, 5 to 10, and Comparative Examples 1 to 9, the above cements were used as binders as shown in Table 1 below, and in Examples 12, 13 and Comparative Examples 10, 11, as shown in Table 1 below. The mixture of the above-mentioned high-strength Portland cement (HC) and fly ash (FA) was used as a binder, and the respective materials used were kneaded in the composition shown in Tables 1 and 2 below to form a cement kneaded product. The mixing of water, binder, coarse aggregate, and fine aggregate when forming the cement kneaded material is shown in Table 1 below.

  Then, the slump and air amount immediately after kneading of the cement kneaded material (0 minute after kneading) and the slump and air amount after stirring with an agitator for 90 minutes (90 minutes after kneading) were measured. The measurement results are shown in Table 2 below. The slump was measured based on the method specified in JIS A 1101, and the air amount was measured based on the method specified in JIS A 1118.

<Summary>
Table 2 shows that when Examples 2 and 3 are compared with Comparative Examples 1 and 2, the slump immediately after kneading is higher in each example. Further, when Examples 5 and 6 are compared with Comparative Examples 3 and 4, it can be seen that the slump immediately after kneading is higher in each example. In addition, comparing Examples 12 and 13 with Comparative Examples 10 and 11, it is recognized that the slump in each example is higher immediately after kneading. In other words, by using the cement composition in which the content of potassium sulfate and the AE water reducing agent is within the scope of the present invention, even when the AE water reducing agent is contained, without being affected by the type of cement, immediately after kneading. It is possible to impart good fluidity (slump) to the kneaded material of (1).

Further, when Examples 2 and 3 are compared with Comparative Examples 1 and 2, Examples 5 and 6 are compared with Comparative Examples 3 and 4, and Examples 12 and 13 are compared with Comparative Examples 10 and 11. It is recognized that the difference between the slump immediately after kneading and the slump after 90 minutes is smaller in each example. That is, in each of the examples, it is possible to reduce a temporal decrease in fluidity immediately after kneading.

  Further, when Examples 7 and 8 are compared with Comparative Examples 5 and 6, it is recognized that the slump immediately after kneading is higher in each Example, and that Examples 9 and 10 are compared with Comparative Examples 7 and 8. It can be seen that the slump immediately after kneading is higher in each example. That is, by using the cement composition in which the contents of potassium sulfate and the AE water reducing agent fall within the range of the present invention, the kneaded material immediately after kneading has good fluidity (slump) without being affected by the type of the AE water reducing agent. ) Can be provided.

  Comparing each example with Comparative Example 9, it is recognized that each example has a higher slump immediately after kneading. That is, by using a cement composition in which the content of potassium sulfate and the AE water reducing agent is within the range of the present invention, the kneaded material immediately after kneading cannot be obtained by using a high-performance AE water reducing agent instead of the AE water reducing agent. Good fluidity (slump) can be obtained.

Further, the difference between the slump immediately after kneading and the slump 90 minutes after kneading in each of Examples 2 and 3 was compared with the difference between the slump immediately after kneading and the slump 90 minutes after kneading in each of Comparative Examples 1 and 2. Then, it is recognized that the difference between the slumps in each example is smaller than the difference between the slumps in each comparative example. In other words, the use of the cement compositions (kneaded cements) of Examples 2 and 3 can suppress a decrease in the slump over time as compared with the cement compositions of Comparative Examples 1 and 2 (kneaded cements).

The difference between the slump immediately after kneading and the slump 90 minutes after kneading in each of Examples 5 and 6 was compared with the difference between the slump immediately after kneading and the slump 90 minutes after kneading in each of Comparative Examples 3 and 4. Then, it is recognized that the difference between the slumps in each example is smaller than the difference between the slumps in each comparative example. That is, the use of the cement compositions of Examples 5 and 6 (kneaded materials of cement) makes it possible to suppress the decrease in slump over time as compared with the cement compositions of Comparative Examples 3 and 4 (kneaded materials of cement).

The difference between the slump immediately after kneading and the slump 90 minutes after kneading in each of Examples 12 and 13 and the difference between the slump immediately after kneading and the slump 90 minutes after kneading in each of Comparative Examples 10 and 11 were compared. Then, it is recognized that the difference between the slumps in each example is smaller than the difference between the slumps in each comparative example. That is, the use of the cement compositions (kneaded cement products) of Examples 12 and 13 can suppress a decrease in the slump over time as compared with the cement compositions (kneaded cement materials) of Comparative Examples 10 and 11.

  The difference between the slump immediately after kneading and the slump 90 minutes after kneading in each of Examples 7 to 10 is a relatively small value in the range of 0.5 cm to 2 cm. That is, the use of the cement compositions (kneaded cement materials) of Examples 7 to 10 can suppress a decrease in slump over time.

Claims (2)

A cement composition that contains cement and forms a hardened body by being kneaded with water and hardening,
1.0 to 2.0 % by mass of potassium sulfate based on the mass of cement and 0.2 to 2.0% by mass of AE water reducing agent based on mass of cement A cement composition characterized by the following. A cement kneaded product obtained by kneading a cement composition containing cement and water,
1.0 to 2.0 % by mass of potassium sulfate based on the mass of cement and 0.2 to 2.0% by mass of AE water reducing agent based on mass of cement A cement kneaded product characterized by the following.