Hydraulic compound

Abstract

To provide a hydraulic compound having improved freezing and thawing resistance without using cement.SOLUTION: A hydraulic compound powder contains a body and water, wherein the powder comprises a powder other than cement and contains 30% or more by volume in the powder of a blast furnace slag fine powder having a specific surface area of 5,000 cm2 / g or more. The other hydraulic compound contains powder and water, wherein the powder consists of a powder other than cement. The powder comprises 80% or more by volume in the powder of a blast furnace slag fine powder having a specific surface area of 3,500 cm2 / g or more. A volume ratio of water to the powder is less than 0.43.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a cement-free hydraulic compound. [Background technology]

[0002] In recent years, hydraulic compounds that do not contain cement have been studied for the purpose of reducing carbon dioxide emissions. Non-Patent Documents 1 to 3 describe concrete compositions that contain blast furnace slag but do not contain cement. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Design and Construction Guidelines for Concrete Structures Using Large Amounts of Admixtures (Draft)", Japan Society of Civil Engineers [Non-Patent Document 2] Kenichi Horiguchi, Junichi Matsumoto, Keisuke Kawamura, and Jun Sakamoto, "Development of secondary concrete products using low-carbon concrete," Proceedings of the Japan Concrete Institute, Vol. 38, No. 1, 2016. [Non-Patent Document 3] Minoru Hata, Makoto Sato, Shingo Miyazawa, "Study on the application of cement-free hardened bodies to various precast concrete products," Proceedings of the Japan Society of Civil Engineers, Vol. 79, No. 1, 2023. Summary of the Invention [Problem to be solved by the invention]

[0004] Non-Patent Documents 1 to 3 state that hydraulic compounds that do not use cement tend to have poor freeze-thaw resistance. The object of the present invention is to provide a hydraulic compound that does not use cement and has improved freeze-thaw resistance. [Means for solving the problem]

[0005] According to one aspect of the present invention, a hydraulic compound includes a powder and water, and the powder is a powder other than cement. The powder has a specific surface area of ​​5000 cm2 The powder contains 30% or more of ground granulated blast furnace slag by volume of 1000 g or more.

[0006] According to another aspect of the present invention, the hydraulic compound includes a powder and water, the powder being a powder other than cement. 2 The powder contains 80% or more by volume of ground granulated blast furnace slag of 80% or more by volume of 1000g or more. The volume ratio of water to the powder is 0.43 or less. Effect of the Invention

[0007] According to the present invention, it is possible to provide a hydraulic compound having improved freeze-thaw resistance without using cement. [Brief description of the drawings]

[0008] [Figure 1] 1 is a graph and a table showing the relative dynamic modulus of elasticity of examples and comparative examples. [Diagram 2] 1 is a graph and a table showing the mass reduction rates of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described below based on examples and comparative examples. Each of the examples and comparative examples is a hydraulic compound (concrete) containing powder, water, fine aggregate, and coarse aggregate. The powder is composed of powder other than cement, and therefore each of the examples and comparative examples is a hydraulic compound that does not contain cement. Table 1 shows the specifications and physical properties of the materials used in each of the examples and comparative examples. Table 2 shows the composition of the hydraulic composition in each of the examples and comparative examples. In the table, W / P indicates the mass ratio and volume ratio of water to powder, s / mor indicates the mortar fine aggregate volume ratio (ratio of fine aggregate volume to mortar volume), and s / a indicates the fine aggregate ratio (ratio of fine aggregate volume to total aggregate volume). Table 3 shows the mass ratio of each component of the powder in each of the examples and comparative examples, and Table 4 shows the volume ratio of each component of the powder in each of the examples and comparative examples. The volume ratio of water to powder (W / P) is in the range of 0.37 to 0.50, taking into account errors. In this specification, the "volume" of a powder means an absolute volume (a volume including voids in powder particles but excluding voids between powder particles). Examples 1-1 to 1-4 may be collectively referred to as Example 1, Examples 2-1 to 2-4 may be collectively referred to as Example 2, Examples 3-1 to 3-3 may be collectively referred to as Example 3, and Examples 4-1 to 4-2 may be collectively referred to as Example 4.

[0010] [Table 1]

[0011] [Table 2]

[0012] [Table 3]

[0013] [Table 4]

[0014] Each of the examples and comparative examples contains at least one of ground granulated blast furnace slag 6000 (BF6) and ground granulated blast furnace slag 4000 (BF4) as powder, as specified in JIS A6206:2013 "ground granulated blast furnace slag for concrete". The specific surface area of ​​ground granulated blast furnace slag 6000 is 5000 cm 2 / g or more 7000cm 2 / g, the specific surface area of ​​ground granulated blast furnace slag 4000 is 3500 cm 2 / g or more 5000cm 2 / g.

[0015] As shown in Tables 2 to 4, Example 1 contains only blast furnace slag 6000 as the ground granulated blast furnace slag. The mass ratio and volume ratio of the ground granulated blast furnace slag 6000 in the powder is 80% or more. Example 2 contains blast furnace slag 6000 and blast furnace slag 4000 as the ground granulated blast furnace slag. The mass ratio and volume ratio of the ground granulated blast furnace slag 6000 and the ground granulated blast furnace slag 4000 combined in the powder is 80% or more. Examples 3-1 and 3-2 contain only blast furnace slag 4000 as the ground granulated blast furnace slag, and further contain fly ash as the powder. The mass ratio and volume ratio of the ground granulated blast furnace slag 4000 and the ground ash combined in the powder is 80% or more. Example 3-3 contains only blast furnace slag 4000 as the ground granulated blast furnace slag, and further contains limestone powder as the powder. The volume ratio of the powder containing the ground granulated blast furnace slag 4000 and the limestone powder is 80% or more. Example 4 and the comparative example contain only ground granulated blast furnace slag 4000 as the ground granulated blast furnace slag. The mass ratio and volume ratio of the ground granulated blast furnace slag 4000 in the powder are 80% or more.

[0016] The powder contains an alkaline stimulant. The alkaline stimulant increases the pH of the surface of the ground granulated blast furnace slag, causing a hydration reaction similar to the hydration reaction of cement. There are no particular limitations on the alkaline stimulant as long as it has the property of increasing the pH, but an expansive material was used in each of the examples and comparative examples. The powder preferably contains 2 to 3% of the expansive material by volume in the powder.

[0017] The powder contains siliceous fine powder. The siliceous fine powder is made of silicon dioxide (SiO2) or is a fine powder containing silicon dioxide as a main component. In an alkaline environment, siliceous substances cause a pozzolanic reaction similar to a hydration reaction. Therefore, the siliceous fine powder functions as a hardening accelerator. In each of the examples and comparative examples, silica fume was used as the siliceous fine powder. Silica fume also has the effect of increasing the fluidity of hydraulic compounds. The powder preferably contains silica fume in a total volume ratio of 14 to 16% in the powder.

[0018] The Examples and Comparative Examples did not contain an air entraining agent, which is a type of surfactant that entrains fine, isolated air bubbles.

[0019] The powder of Example 1 has a specific surface area of ​​5000 cm 2 The powder in Example 2 is composed of ground granulated blast furnace slag with a specific surface area of ​​5000 cm or more and silica fume and an expansive material. 2 / g or more and a specific surface area of ​​3500 cm 2 / g or more 5000cm 2 The powder in Example 3 is composed of ground granulated blast furnace slag with a specific surface area of ​​less than 5000 cm / g, silica fume, and an expansive material. 2 The powder in Example 4 is composed of ground granulated blast furnace slag having a specific surface area of ​​3,500 cm3 / g or more, fly ash (Examples 3-1 and 3-2) or ground limestone (Example 3-3), silica fume, and an expansive material. 2 / g or more 5000cm 2 It consists only of ground granulated blast furnace slag with a viscosity of less than 1000 g / g, silica fume, and an expanding agent.

[0020] FIG. 1(a) is a graph of the relative dynamic modulus of elasticity for the examples and comparative examples, and FIG. 1(b) shows the numerical values. FIG. 2(a) is a graph of the mass loss rate for the examples and comparative examples, and FIG. 2(b) shows the numerical values. The relative dynamic modulus of elasticity and the mass loss rate were determined based on the underwater freeze-thaw test method (Method A) specified in JIS A1148:2010 "Concrete freeze-thaw test method". If the relative dynamic modulus of elasticity is 60% or more of the initial value after 300 cycles, it can be evaluated as having excellent freeze-thaw resistance. In the comparative example, the relative dynamic modulus of elasticity fell below 60% of the initial value at about 170 cycles, whereas in each example, it exceeded 60% of the initial value even after 300 cycles, and in most examples, it remained at about 90% or more of the initial value. From this, it was found that each example had excellent freeze-thaw resistance.

[0021] Examples 1 to 3 contain 30% or more of ground granulated blast furnace slag 6000 in terms of mass ratio and volume ratio in the powder. The reason why the freeze-thaw resistance is improved by using ground granulated blast furnace slag 6000 is believed to be because the high fineness of ground granulated blast furnace slag 6000 makes it easier to densify the structure of the hydraulic compound. This is believed to be because the hydration reaction proceeds more quickly. In addition, the high fineness improves the packing ability of the powder, which may also contribute to the densification of the structure. Table 1 shows the compressive strength of each example and comparative example, and each example has a higher compressive strength than the comparative example, which is believed to be due to the hydration reaction proceeding more quickly. All of Examples 1 to 3 had a compressive strength of 99 N / mm when sealed at 20°C after 28 days of material age. 2 That was all.

[0022] Example 4, which contained only Blast Furnace Slag Powder 4000 as the ground granulated blast furnace slag, also showed excellent freeze-thaw resistance. However, Example 4 and the comparative example had the same powder composition, and only the volume ratio of water to powder (W / P) was different. This shows that when only Blast Furnace Slag Powder 4000 is contained as the ground granulated blast furnace slag, it is possible to improve freeze-thaw resistance by adjusting the W / P, and it is particularly preferable to set the W / P to 0.43 or less, and more preferably to set it to 0.4 or less. Furthermore, the compressive strength of Example 4 at an age of 28 days and sealed at 20°C was 98 N / mm2 That was all.

[0023] As mentioned above, none of the examples contain air-entraining agents. Air-entraining agents are known to contribute to improving freeze-thaw resistance. This is thought to be because the air bubbles entrained by the air-entraining agent act as a sort of cushion. However, in order to adjust the air content to an appropriate level, careful adjustment of the air-entraining agent blend is necessary. None of the examples require such air-entraining agents and are easy to blend.

[0024] Next, the data described in Non-Patent Documents 1 to 3 were examined. Table 5 shows the specifications and physical properties of the materials used. Table 6 shows the concrete mix and freeze-thaw resistance. For freeze-thaw resistance, those in which the relative dynamic modulus of elasticity dropped sharply with an increase in cycles were marked with "NG," and those in which the relative dynamic modulus of elasticity showed little change even with an increase in cycles were marked with "OK."

[0025] [Table 5]

[0026] [Table 6]

[0027] All the comparative examples shown in Tables 5 and 6 contain ground granulated blast furnace slag, but all have a specific surface area of ​​5000 cm 2The BF4 was less than / g. Therefore, most of the comparative examples were NG in terms of freeze-thaw resistance. Comparative Example 1-1 had OK freeze-thaw resistance, but the air content was very large at 6%. On the other hand, Comparative Example 1-3 had NG freeze-thaw resistance, but the AE agent used was different from that used in Comparative Example 1-1, and the difference in air content was small. This means that in order to ensure freeze-thaw resistance in this type of concrete, it is necessary not only to ensure the amount of air entrained by the AE agent, but also to appropriately select the AE agent to be used. In contrast, each of the examples did not entrain fine air bubbles using the AE agent. The measured air content was in the range of 1.4 to 3.4%, and was generally less than 3.5% even when the error was taken into account. In addition, a comparison between Examples 2-1 and 2-2 showed that there was no significant effect on the relative dynamic modulus of elasticity due to the change in the air content (see Figure 1).

[0028] Comparative Example 3-2 has OK freeze-thaw resistance, but the amount of AE agent added is very large. Non-Patent Document 1 reports that if the AE agent is selected inappropriately, the freeze-thaw resistance may be poor, so care must be taken when selecting the AE agent. Comparative Example 3-3 has OK freeze-thaw resistance, but uses a special material called paraffin-based emulsion. In the examples, no AE agent is used, and no special material such as paraffin-based emulsion is used. In this way, it can be seen that each example can improve freeze-thaw resistance with a relatively simple composition, even compared to the prior art.

[0029] Although the present invention has been described above using examples and comparative examples, the present invention is not limited to these examples. In each example, ground granulated blast furnace slag 6000 was used, but ground granulated blast furnace slag 8000 (specific surface area 7000 cm) specified in JIS A6206:2013 "ground granulated blast furnace slag for concrete" was also used. 2 / g or more 10000cm 2 / g) may be used. In addition, although each example includes a coarse aggregate, mortars that do not include a coarse aggregate are also included in the scope of the present invention.

Claims

1. Contains powder and water, The powder is a powder other than cement and has a specific surface area of ​​5000 cm 2 The hydraulic compound contains 30% or more of ground granulated blast furnace slag in a volume ratio of 100 / g or more in the powder.

2. The powder has a specific surface area of ​​5000 cm 2 2. The hydraulic compound according to claim 1, wherein the powder contains 80% or more of ground granulated blast furnace slag having a volume ratio of 1:1 or more to 1:1 ....

3. The powder has a specific surface area of ​​5000 cm 2 3. The hydraulic compound according to claim 2, which consists essentially of ground granulated blast furnace slag having a viscosity of at least 100000000 / g, silica fume, and an expansive material.

4. The powder has a specific surface area of ​​5000 cm 2 / g or more of ground granulated blast furnace slag and a specific surface area of ​​3500 cm 2 / g or more 5000cm 2 2. The hydraulic compound according to claim 1, wherein the powder contains 80% or more of ground granulated blast furnace slag having a volume ratio of less than 1 / g.

5. The powder has a specific surface area of ​​5000 cm 2 / g or more and the specific surface area of ​​3500 cm 2 / g or more 5000cm 2 5. The hydraulic compound according to claim 4, which consists of ground granulated blast furnace slag having a viscosity of less than 1000 g / g, silica fume, and an expansive material.

6. The powder has a specific surface area of ​​5000 cm 2 2. The hydraulic compound according to claim 1, wherein the powder contains 80% or more of ground granulated blast furnace slag and fly ash in a volume ratio of 80% or more.

7. The powder has a specific surface area of ​​5000 cm 2 7. The hydraulic compound according to claim 6, which consists essentially of ground granulated blast furnace slag having a viscosity of 100 / g or more, fly ash, silica fume, and an expansive material.

8. The powder has a specific surface area of ​​5000 cm 2 2. The hydraulic compound according to claim 1, wherein the powder contains 80% or more of ground granulated blast furnace slag and limestone powder in a volume ratio of 80% or more in total.

9. The powder has a specific surface area of ​​5000 cm 2 9. The hydraulic compound according to claim 8, which consists essentially of ground granulated blast furnace slag having a viscosity of at least 1000 saturation point of 100 / g, ground limestone, silica fume, and an expansive material.

10. 2. The hydraulic compound according to claim 1, wherein the volume ratio of water to the powder is 0.37 or more and 0.50 or less.

11. Contains powder and water, The powder is a powder other than cement and has a specific surface area of ​​3500 cm 2 1. A hydraulic compound comprising 80% or more ground granulated blast furnace slag in a volume ratio of 100 / g or more in said powder, and a volume ratio of said water to said powder of 0.43 or less.

12. The powder has a specific surface area of ​​3500 cm 2 / g or more 5000cm 2 12. The hydraulic compound according to claim 11, which consists of ground granulated blast furnace slag having a viscosity of less than 1000 g / g, silica fume, and an expansive material.

13. The hydraulic compound according to claim 1 , 2 , 4 , 6 , 8 , 10 , or 11 , wherein the powder comprises an alkaline irritant.

14. The hydraulic compound according to claim 13, wherein the alkaline stimulant is an expansion material, and the powder contains the expansion material in an amount of 2 to 3% by volume in the powder.

15. The hydraulic compound according to any one of claims 1 to 11, wherein the powder comprises a siliceous fine powder.

16. The hydraulic compound according to claim 15, wherein the siliceous fine powder is silica fume, and the powder contains 14 to 16% of the silica fume by volume ratio in the powder.

17. 13. The hydraulic compound according to claim 1, which does not contain an air entraining agent.

18. 13. Hydraulic compound according to any one of claims 1 to 12, having an air content of less than or equal to 3.5%.

19. Compressive strength at 28 days old and sealed at 20°C is 98N / mm 2 The hydraulic compound according to any one of claims 1 to 12, wherein

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