hydraulic materials

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] This invention relates to hydraulic materials. [Background technology]

[0002] Patent Document 1, listed below, describes a hydraulic material containing Portland cement, anhydrous gypsum powder, and blast furnace slag powder. The same document also describes the production of high-strength mortar by mixing the hydraulic material with water. The Portland cement content of this hydraulic material is stated to be 90% by mass or more.

[0003] Incidentally, the production of Portland cement requires a cement firing process. This process emits a large amount of carbon dioxide. On the other hand, in recent years there has been a demand to reduce carbon dioxide emissions. However, when only a small amount of Portland cement is used as a 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] Japanese Patent Publication No. 2020-183338 [Overview of the project] [Problems that the invention aims to solve]

[0005] The objective of the present invention is to provide a hydraulic material that can produce high-strength mortar despite containing only a small amount of Portland cement. [Means for solving the problem]

[0006] The hydraulic material according to the first item of the present invention comprises Portland cement, gypsum powder, and blast furnace slag powder. In this hydraulic material, 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.

[0007] Here, the Portland cement can be, for example, ordinary Portland cement, rapid-hardening Portland cement, moderate-heat Portland cement, low-heat Portland cement, or sulfate-resistant Portland cement, or a mixture of two or more of these. The gypsum powder can be, for example, anhydrous gypsum powder, dihydrate gypsum powder, or a mixture thereof.

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

[0009] In the hydraulic material according to the second item 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 point, it is possible to manufacture even higher-strength mortar. This point will be explained in detail in the test examples described later.

[0011] The hydraulic material according to the third item of the present invention has a specific surface area of ​​8000 cm² of blast furnace slag powder. 2 The strength must be at least / g. According to the third item, even higher-strength mortar can be manufactured. This point will be explained 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] FIG. 1 is a graph showing the results in a test example of a hydraulic material according to an embodiment of the present invention, and shows the relationship between the Portland cement content of the hydraulic material and the compressive strength of the mortar. [Figure 2] FIG. 2 is a graph showing the results in a test example of a hydraulic material according to an embodiment of the present invention, and shows the relationship between the anhydrous gypsum powder content of the hydraulic material and the compressive strength of the mortar. [Figure 3] FIG. 3 is a graph showing the results in a test example of a hydraulic material according to an embodiment of the present invention, and shows the relationship between the specific surface area of blast furnace slag powder contained in the hydraulic material and the compressive strength of the mortar.

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 and mixing 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 preferable that this ratio is 2% or more and 6% or less, and even more preferable that this ratio is 3% or more and 5% or less.

[0016] In order to produce high-strength mortar by kneading and mixing 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 preferable that this ratio is 10% or more, and even more preferable that this ratio is 15% or more.

[0017] As the Portland cement, for example, any one of ordinary Portland cement, early strength Portland cement, moderate 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 hydraulic materials, water, and fine aggregate, it is preferable that the specific surface area of 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 "Physical Testing Methods 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 the above comparative examples, ordinary Portland cement, anhydrous gypsum powder, and blast furnace slag powder were mixed to produce 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 together to produce 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 "Physical Testing Methods 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 for the strength test. Thereby, mortar was obtained. Then, 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

[0022] Table 1 shows the parameters of the blast furnace slag powders (blast furnace slag powders A, B, and C) used in each example and comparative example, namely the chemical composition (from ig. loss to basicity) and density (g / cm³). 3 This indicates the chemical composition. The unit of 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 comparative example shown in Table 2, the Portland cement content of the hydraulic material differs from one another. Figure 1 plots the relationship between the Portland cement content and compressive strength in each example and comparative example shown in Table 2.

[0025] In Table 2, the "3-day age" column indicates the compressive strength of the mortar at 3 days of age (hereinafter referred to as "3-day strength"). The "7-day age" column indicates the compressive strength of the mortar at 7 days of age (hereinafter referred to as "7-day strength"). The "28-day age" column indicates the compressive strength of the mortar at 28 days of age (hereinafter referred to as "28-day strength"). Furthermore, the Portland cement content refers to 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, if the Portland cement content of the hydraulic material is between 0.5% and 9% by mass, the 28-day strength of the mortar will be 50 N / mm². 2Since it can be estimated that it exceeds [a certain value], it is preferable. 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 Since it can be estimated that it exceeds [a certain value], it is more preferable. 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 It becomes [a certain level] and is particularly preferable. As shown in FIG. 1, when the Portland cement content of the hydraulic material is within the above-mentioned 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] Considering 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 exceeds 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 exceeds 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 exceeds 50 N / mm 2 If the anhydrous gypsum powder content of the hydraulic material is 15% by mass or more, it is particularly preferable that it exceeds 50 N / mm. As shown in FIG. 2, when the anhydrous gypsum powder content of the hydraulic material is within the above-mentioned 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 the mortar in Examples 10-15. In each example shown in Table 4, the type or specific surface area of ​​the blast furnace slag powder differs from one another. Figure 3 plots the relationship between the type and specific surface area of ​​blast furnace slag powder and the compressive strength of the mortar in each example shown in Table 4. In Figure 3, the black plots relate to Example 14, which used blast furnace slag powder A. The gray plots relate to Example 15, which used blast furnace slag powder B. The white plots relate to Examples 10-13, which used blast furnace slag powder C. In each example shown in Table 4, the Portland cement content of the hydraulic material was set to 3% by mass, the anhydrous gypsum powder content to 30% by mass, and the blast furnace slag powder content to 67% by mass.

[0032] [Table 4]

[0033] Based on the plot 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). Furthermore, when the specific surface area of ​​the blast furnace slag powder reaches 8000 cm²... 2 In the range of 8000 cm² or more, the compressive strength of the mortar increases sharply with increasing specific surface area of ​​blast furnace slag powder. Therefore, when the specific surface area of ​​blast furnace slag powder is 8000 cm², 2 It is preferable that the value be 1 / g or more.

[0034] As described above, according to the above embodiment, a high-strength mortar can be produced by mixing 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, and more preferably 3% by mass or more and 5% by mass or less) with water.

[0035] Furthermore, according to the above embodiment, by setting the anhydrous gypsum powder content to 5% by mass or more (preferably 10% by mass or more, and more preferably 15% by mass or more), an even higher-strength mortar can be produced.

[0036] Furthermore, according to the above embodiment, the specific surface area of ​​the blast furnace slag powder used in the hydraulic material is 8000 cm². 2 By setting the weight to 1 / g or higher, it is possible to manufacture mortar with even higher strength.

[0037] Thus, according to the above embodiment, high-strength mortar can be produced by mixing a hydraulic material containing only a small amount of Portland cement compared to conventional hydraulic materials with water. In other words, high-strength mortar can be produced 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 emitted from the cement firing apparatus can be reduced by approximately 90%.

[0038] Furthermore, according to the above embodiment, high strength can be achieved in mortar obtained by curing a mixture of hydraulic material and water at 20°C. Therefore, there is no need to perform autoclave curing, steam curing, or heat curing to achieve the strength of the mortar. In other words, energy required for curing this mixture can be saved.

[0039] In the above embodiment, dihydrate gypsum powder can be used instead of anhydrous gypsum powder. Alternatively, a mixture of anhydrous gypsum powder and dihydrate gypsum powder can be used instead of anhydrous gypsum powder.

Claims

1. A hydraulic material comprising Portland cement, gypsum powder, and blast furnace slag powder, The ratio of the mass of Portland cement to the total mass of the Portland cement, gypsum powder, and blast furnace slag powder is 2% or more and 3% or less. The ratio of the mass of the gypsum powder to the total mass is 15% or more and 30% or less. The specific surface area of ​​the blast furnace slag powder is 8000 cm². 2 A hydraulic material characterized by having a density of 1 / g or more.

2. The hydraulic material according to claim 1, characterized in that the ratio of the mass of Portland cement to the total mass is 3%.

3. The hydraulic material according to claim 1 or 2, characterized in that the Portland cement is any of ordinary Portland cement, rapid-hardening Portland cement, moderate-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement, or a mixture of two or more of these.

4. The hydraulic material according to any one of claims 1 to 3, characterized in that the gypsum powder is one of anhydrous gypsum powder, one of dihydrate gypsum powder, or a mixture thereof.

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