Hydraulic material

Abstract

To provide a hydraulic material that can produce high-strength mortar despite containing only a small amount of Portland cement.SOLUTION: The hydraulic material comprises Portland cement, gypsum powder and blast furnace slag powder. The ratio of the mass of Portland cement to the total mass of Portland cement, gypsum powder and blast furnace slag powder is 0.5% or more and 9% or less. It is preferable that the ratio of the mass of gypsum powder to the total mass is 5% or more. As the Portland cement, any one of normal Portland cement, high-early-strength Portland cement, moderate-heat Portland cement, low-heat Portland cement, and sulfate-resistant Portland cement, or a mixture of two or more thereof can be used. It is preferable that the specific surface area of the blast furnace slag powder is 8000 cm2 / g or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to hydraulic materials.

Background Art

[0002] Patent Document 1 below describes a hydraulic material containing Portland cement, anhydrous gypsum powder, and blast furnace slag powder. Further, it describes that high-strength mortar is produced by kneading the hydraulic material and water. The Portland cement content of this hydraulic material is 90% by mass or more.

[0003] By the way, a cement firing process is required to produce Portland cement. A large amount of carbon dioxide is emitted from this process. On the other hand, in recent years, reduction of carbon dioxide emissions has been demanded. However, when only a small amount of Portland cement is used as the hydraulic material, the strength of the mortar obtained from the hydraulic material tends to be insufficient.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a hydraulic material capable of producing high-strength mortar despite containing only a small amount of Portland cement.

Means for Solving the Problems

[0006] The hydraulic material according to the first aspect of the present invention contains Portland cement, gypsum powder, and blast furnace slag powder. In this hydraulic material, the ratio of the mass of the Portland cement to the total mass of the Portland cement, the gypsum powder, and the blast furnace slag powder is 0.5% or more and 9% or less.

[0007] Here, as the Portland cement, for example, any one of ordinary Portland cement, early-strength Portland cement, medium-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement, or a mixture of two or more of these can be used. As the gypsum powder, for example, any one of anhydrous gypsum powder and dihydrate gypsum powder, or a mixture thereof can be used.

[0008] According to the first aspect, compared with the technology described in Patent Document 1 above, the hydraulic material contains only a small amount of Portland cement. However, when this hydraulic material and water are kneaded together, high-strength mortar can be produced. This point will be described in detail in the test examples described later.

[0009] In the hydraulic material according to the second aspect of the present invention, the ratio of the mass of the gypsum powder to the total mass is 5% or more.

[0010] According to the second aspect, even higher-strength mortar can be produced. This point will be described in detail in the test examples described later.

[0011] The hydraulic material according to the third aspect of the present invention has a specific surface area of the blast furnace slag powder of 8000 cm 2 / g or more. According to the third aspect, even higher-strength mortar can be produced. This point will be described in detail in the test examples described later.

Effects of the Invention

[0012] As described above, according to the present invention, it is possible to provide a hydraulic material capable of producing high-strength mortar despite containing only a small amount of Portland cement.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0014] A hydraulic material according to an embodiment of the present invention will be described. This hydraulic material contains Portland cement, anhydrous gypsum powder, and blast furnace slag powder.

[0015] In order to produce high-strength mortar by kneading the hydraulic material, water, and fine aggregate, the ratio of the mass of Portland cement to the total mass of Portland cement, anhydrous gypsum powder, and blast furnace slag powder needs to be 0.5% or more and 9% or less. Further, it is more preferably 2% or more and 6% or less, and even more preferably 3% or more and 5% or less.

[0016] In order to produce high-strength mortar by kneading the hydraulic material, water, and fine aggregate, the ratio of the mass of anhydrous gypsum powder to the above total mass is preferably 5% or more. Further, it is more preferably 10% or more, and even more preferably 15% or more.

[0017] As the Portland cement, for example, any one of ordinary Portland cement, early-strength Portland cement, medium-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement, or a mixture of two or more of these can be used.

[0018] To produce high-strength mortar by kneading a hydraulic material, water, and fine aggregate, it is preferable that the specific surface area of the blast furnace slag powder is 8000 cm 2 / g or more. In this specification, the specific surface area means the specific surface area measured using a Blaine air permeability apparatus. The specific measurement method of this specific surface area is defined in Japanese Industrial Standard JIS R 5201 "Methods of physical tests for cement".

[0019] Next, examples and comparative examples of the hydraulic material according to an embodiment of the present invention will be described. In the above examples and above comparative examples, ordinary Portland cement, anhydrous gypsum powder, and blast furnace slag powder were mixed to prepare a hydraulic material. As the anhydrous gypsum powder, one having a specific surface area of 4680 cm 2 / g (Type II anhydrous gypsum manufactured by Soekawa Rikagaku Co., Ltd.) was used.

[0020] Furthermore, this hydraulic material, fine aggregate, and water were kneaded to prepare a kneaded product. Specifically, 450 g of the hydraulic material, 1350 g of the fine aggregate, and 225 g of water were weighed and kneaded using a Hobart mixer in accordance with JIS R 5201 "Methods of physical tests for cement". The kneaded product was molded using a steel mold with an inner dimension of 4 × 4 × 16 cm. After 24 hours of molding, it was demolded and sealed and cured in a room at 20°C until the age of the strength test. Thereby, mortar was obtained. And the compressive strength of this mortar was measured.

[0021] Here, ordinary Portland cement is a mixed powder composed of cement clinker powder, dihydrate gypsum powder, and hemihydrate gypsum powder, and is defined in JIS R 5210 "Portland cement". The compressive strength was measured in accordance with JIS R 5201 "Methods of physical tests for cement".

[0022] Table 1 shows the chemical composition (from ignition loss to basicity) and density (g / cm 3 ) of blast furnace slag powders (blast furnace slag powders A, B, and C) used in each example and each comparative example. The unit of the chemical composition is mass%.

[0023] [Table 1]

[0024] Table 2 shows the relationship between the composition of the hydraulic material and the compressive strength of the mortar in Examples 1-4 and Comparative Examples 1-2. In each example and each comparative example shown in Table 2, the Portland cement content of the hydraulic material is different from each other. Figure 1 shows a plot of the relationship between the Portland cement content and the compressive strength in each example and each comparative example shown in Table 2.

[0025] In Table 2, the item "age 3 days" indicates the compressive strength of the mortar (hereinafter referred to as "3-day strength") at the time when the age of the mortar is 3 days. The item "age 7 days" indicates the compressive strength of the mortar (hereinafter referred to as "7-day strength") at the time when the age of the mortar is 7 days. The item "age 28 days" indicates the compressive strength of the mortar (hereinafter referred to as "28-day strength") at the time when the age of the mortar is 28 days. Also, the Portland cement content means the ratio of the mass of Portland cement to the total mass of Portland cement, anhydrous gypsum powder, and blast furnace slag powder.

[0026] [Table 2]

[0027] Based on the plot shown in Figure 1, when the Portland cement content of the hydraulic material is 0.5 mass% or more and 9 mass% or less, the 28-day strength of the mortar is 50 N / mm 2is preferably more than this. If the Portland cement content of the hydraulic material is 2% by mass or more and 6% by mass or less, the 28-day strength of the mortar is 60 N / mm 2 is preferably more than this. If the Portland cement content of the hydraulic material is 3% by mass or more and 5% by mass or less, the 28-day strength of the mortar is 65 N / mm 2 which is particularly preferable. As shown in FIG. 1, when the Portland cement content of the hydraulic material is within the above-described preferable range, the 3-day strength and 7-day strength of the mortar are also as high as the 28-day strength.

[0028] Table 3 shows the relationship between the composition of the hydraulic material and the compressive strength of the mortar in Examples 1, 5 to 9 and Comparative Example 3. In each of the examples and comparative examples shown in Table 3, the anhydrous gypsum powder content of the hydraulic material is different from each other. FIG. 2 shows a plot of the relationship between the anhydrous gypsum powder content and the compressive strength in each of the examples and comparative examples shown in Table 3. The anhydrous gypsum powder content means the ratio of the mass of anhydrous gypsum powder to the total mass of Portland cement, anhydrous gypsum powder and blast furnace slag powder.

[0029]

Table 3

[0030] Based on the plot shown in FIG. 2, if the anhydrous gypsum powder content of the hydraulic material is 5% by mass or more, the 28-day strength of the mortar is preferably more than 25 N / mm 2 If the anhydrous gypsum powder content of the hydraulic material is 10% by mass or more, the 28-day strength of the mortar is more preferably more than 40 N / mm 2 If the anhydrous gypsum powder content of the hydraulic material is 15% by mass or more, the 28-day strength of the mortar is particularly preferably more than 50 N / mm 2 As shown in FIG. 2, when the anhydrous gypsum powder content of the hydraulic material is within the above-described preferable range, the 3-day strength and 7-day strength of the mortar are also as high as the 28-day strength.

[0031] Table 4 shows the relationship between the type and specific surface area of blast furnace slag powder and the compressive strength of mortar in Examples 10-15. In each of the examples shown in Table 4, the type or specific surface area of the blast furnace slag powder is different from each other. Figure 3 shows a plot of the relationship between the type and specific surface area of blast furnace slag powder and the compressive strength of mortar in each of the examples shown in Table 4. In Figure 3, the black plot relates to Example 14 using blast furnace slag powder A. The gray plot relates to Example 15 using blast furnace slag powder B. The white plot relates to Examples 10-13 using blast furnace slag powder C. In each of the examples shown in Table 4, the Portland cement content of the hydraulic material was 3% by mass, the anhydrous gypsum powder content was 30% by mass, and the blast furnace slag powder content was 67% by mass.

[0032]

Table 4

[0033] Considering based on the plots shown in Figure 3, the compressive strength of the mortar increases as the specific surface area of the blast furnace slag powder increases, regardless of the type of blast furnace slag powder (i.e., the chemical composition of the blast furnace slag powder). And in the range where the specific surface area of the blast furnace slag powder is 8000 cm 2 / g or more, the compressive strength of the mortar increases rapidly with the increase in the specific surface area of the blast furnace slag powder. Therefore, it is preferable that the specific surface area of the blast furnace slag powder is 8000 cm 2 / g or more.

[0034] As described above, according to the above embodiment, by kneading a hydraulic material having a Portland cement content of 0.5% by mass or more and 9% by mass or less (preferably 2% by mass or more and 6% by mass or less, more preferably 3% by mass or more and 5% by mass or less) and water, high-strength mortar can be produced.

[0035] Further, according to the above-described embodiment, by setting the anhydrous gypsum powder content to 5% by mass or more (preferably 10% by mass or more, more preferably 15% by mass or more), it is possible to produce even higher-strength mortar.

[0036] Furthermore, according to the above-described embodiment, by setting the specific surface area of the blast furnace slag powder used as the hydraulic material to 8000 cm 2 / g or more, it is possible to produce even higher-strength mortar.

[0037] Thus, according to the above-described embodiment, by kneading a hydraulic material containing only a small amount of Portland cement compared to conventional hydraulic materials and water, it is possible to produce high-strength mortar. That is, it is possible to produce high-strength mortar without producing a large amount of Portland cement in the cement firing apparatus. Therefore, the amount of Portland cement produced in the cement firing apparatus can be reduced, and the amount of carbon dioxide discharged from the cement firing apparatus can be reduced by about 90%.

[0038] Furthermore, according to the above-described embodiment, it is possible to develop high strength in the mortar obtained by curing at 20°C from the kneaded product of the hydraulic material and water. For this reason, it is not necessary to perform autoclave curing, steam curing, or heat curing for developing the strength of the mortar. That is, the energy required for curing this kneaded product can also be saved.

[0039] In addition, in the above-described embodiment, dihydrate gypsum powder can be used instead of anhydrous gypsum powder. Also, instead of anhydrous gypsum powder, a mixture of anhydrous gypsum powder and dihydrate gypsum powder can be used.

Claims

1. A hydraulic material containing Portland cement, gypsum powder, and blast furnace slag powder, wherein the ratio of the mass of the Portland cement to the total mass of the Portland cement, the gypsum powder, and the blast furnace slag powder is 0.5% or more and 9% or less. A hydraulic material characterized by this.

2. The hydraulic material according to Claim 1, wherein the ratio of the mass of the gypsum powder to the total mass is 5% or more.

3. The Portland cement is any one of ordinary Portland cement, rapid hardening Portland cement, medium heat Portland cement, low heat Portland cement, sulfate resistant Portland cement, or a mixture of two or more of these. The hydraulic material according to Claim 1 or 2, characterized by this.

4. The hydraulic material according to any one of Claims 1 to 3, wherein the gypsum powder is any one of anhydrite powder and dihydrate gypsum powder, or a mixture thereof.

5. The specific surface area of the blast furnace slag powder is 8000 cm 2 / g or more, and the hydraulic material according to any one of claims 1 to 4, characterized in that.

Images