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] The present invention relates to a hydraulic material. [Background technology]

[0002] The following Patent Document 1 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 kneading the hydraulic material with water. The Portland cement content of this hydraulic material is 90% by mass or more.

[0003] By the way, the production of Portland cement requires a cement burning process. This process emits a large amount of carbon dioxide. Meanwhile, in recent years, there has been a demand for reducing 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] JP 2020-183338 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a hydraulic material which can produce a 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 aspect of the present invention comprises Portland cement, gypsum powder, and blast furnace slag powder, and 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] The Portland cement may be, for example, any one of ordinary 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 of these.The gypsum powder may be, for example, any one of anhydrous gypsum powder and dihydrate gypsum powder, or a mixture of these.

[0008] According to the first item, compared to the technology described in the above 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 example 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 item, it is possible to produce a mortar with even higher strength, which will be described in detail in the test examples below.

[0011] The hydraulic material according to the third aspect of the present invention is characterized in that the specific surface area of ​​the blast furnace slag powder is 8000 cm 2 / g or more. According to the third item, it is possible to produce a mortar with even higher strength. This point will be explained in detail in the test examples described later. Effect of the Invention

[0012] As described above, according to the present invention, it is possible to provide a hydraulic material that can produce high-strength mortar even though it contains only a small amount of Portland cement. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a graph showing the results of a test example of a hydraulic material according to one embodiment of the present invention, showing the relationship between the Portland cement content of the hydraulic material and the compressive strength of the mortar. [Diagram 2] FIG. 2 is a graph showing the results of a test example of a hydraulic material according to one embodiment of the present invention, showing the relationship between the anhydrous gypsum powder content in the hydraulic material and the compressive strength of the mortar. [Diagram 3] FIG. 3 is a graph showing the results of a test example of a hydraulic material according to one embodiment of the present invention, and shows the relationship between the specific surface area of ​​the blast furnace slag powder contained in the hydraulic material and the compressive strength of the mortar. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0015] To manufacture high-strength mortar by mixing hydraulic materials, 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 must be 0.5% to 9%. This ratio is more preferably 2% to 6%, and even more preferably 3% to 5%.

[0016] To manufacture high-strength mortar by mixing hydraulic material, water, and fine aggregate, the mass ratio of the anhydrous gypsum powder to the total mass is preferably 5% or more, 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, 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 of these, can be used.

[0018] To manufacture high-strength mortar by mixing hydraulic materials, water, and fine aggregate, the specific surface area of ​​blast furnace slag powder must be 8000 cm 2 / g or more. In this specification, the specific surface area means the specific surface area measured using a Blaine air permeation device. The specific method for measuring the specific surface area is specified in the Japanese Industrial Standard JIS R 5201 "Physical Testing Methods for Cement."

[0019] Next, examples and comparative examples of the hydraulic material according to one embodiment of the present invention will be described. In the above examples and comparative examples, ordinary Portland cement, anhydrous gypsum powder, and blast furnace slag powder were mixed to prepare the hydraulic material. The anhydrous gypsum powder was used as the material 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 was mixed with fine aggregate and water to prepare a kneaded product. Specifically, 450g of hydraulic material, 1350g of fine aggregate, and 225g of water were weighed out and mixed using a Hobart mixer in accordance with JIS R 5201 "Physical Test Methods for Cement". The kneaded product was molded using a steel formwork with inner dimensions of 4 x 4 x 16 cm. After 24 hours of molding, the mixture was removed from the form and sealed and cured in a room at 20°C until the material age for the strength test. Mortar was thus obtained. The compressive strength of this mortar was then measured.

[0021] Here, ordinary Portland cement is a mixed powder consisting of cement clinker powder, gypsum dihydrate powder, and gypsum hemihydrate powder, and is specified in JIS R 5210 "Portland cement." The compressive strength was measured in accordance with JIS R 5201 "Physical testing methods for cement."

[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, such as chemical composition (from ig. loss to basicity) and density (g / cm 3 The chemical composition is in 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. The Portland cement content of the hydraulic material is different in each Example and Comparative Example shown in Table 2. Figure 1 shows a plot of the relationship between the Portland cement content and the compressive strength in each Example and Comparative Example shown in Table 2.

[0025] In Table 2, the "3 day age" item indicates the compressive strength of the mortar when the mortar is 3 days old (hereinafter referred to as "3 day strength"). The "7 day age" item indicates the compressive strength of the mortar when the mortar is 7 days old (hereinafter referred to as "7 day strength"). The "28 day age" item indicates the compressive strength of the mortar when the mortar is 28 days old (hereinafter referred to as "28 day strength"). In addition, 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, if the Portland cement content of the hydraulic material is between 0.5% and 9% by mass, the 28-day strength of the mortar is 50 N / mm 2If the Portland cement content of the hydraulic material is between 2% and 6% by mass, the 28-day strength of the mortar will be 60 N / mm 2 If the Portland cement content of the hydraulic material is between 3% and 5% by mass, the 28-day strength of the mortar will exceed 65 N / mm. 2 As shown in Fig. 1, when the Portland cement content of the hydraulic material is within the above-mentioned preferred range, the 3-day and 7-day strengths of the mortar are high, as is 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 Example and Comparative Example 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 Example and Comparative Example shown in Table 3. The anhydrous gypsum powder content means the ratio of the mass of the anhydrous gypsum powder to the total mass of the Portland cement, the anhydrous gypsum powder, and the blast furnace slag powder.

[0029] [Table 3]

[0030] Based on the plot shown in Figure 2, if the anhydrous gypsum powder content of the hydraulic material is 5 mass% or more, the 28-day strength of the mortar is 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 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 50 N / mm 2 As shown in Fig. 2, when the content of anhydrous gypsum powder in the hydraulic material is within the above-mentioned preferred range, the 3-day strength and 7-day strength of the mortar are high, as is the 28-day strength.

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

[0032] [Table 4]

[0033] Based on the plot shown in FIG. 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). 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. 2 It is preferable that the molecular weight is 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 with 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 content of the anhydrous gypsum powder to 5% by mass or more (preferably 10% by mass or more, and more preferably 15% by mass or more), a mortar with even higher strength 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 set to 8000 cm 2 By making the mortar strength larger, it is possible to produce a mortar having a higher strength.

[0037] Thus, according to the above embodiment, high-strength mortar can be produced by kneading water with a hydraulic material that contains only a small amount of Portland cement compared to conventional hydraulic materials. That is, 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 about 90%.

[0038] Furthermore, according to the embodiment, the mortar obtained by curing the mixture of hydraulic material and water at 20°C can have high strength. Therefore, there is no need to perform autoclave curing, steam curing, or heat curing to develop the strength of the mortar. In other words, it is possible to save energy required for curing the mixture.

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

Claims

1. A hydraulic material comprising Portland cement, gypsum powder and blast furnace slag powder, 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 2% or more and 6% or less, The ratio of the mass of the gypsum powder to the total mass is 20% or more, The specific surface area of ​​the blast furnace slag powder is 8000 cm 2 / g or more A hydraulic material characterized by:

2. 2. The hydraulic material according to claim 1, wherein the Portland cement is any one of ordinary 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 of these.

3. 3. The hydraulic material according to claim 1, wherein the gypsum powder is either one of anhydrous gypsum powder and dihydrate gypsum powder, or a mixture thereof.

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