High-strength steel fiber reinforced mortar and its manufacturing method

Abstract

To provide a high-strength fiber-reinforced mortar having an adjustable setting time and / or setting start time, a resistance to material segregation, kneadability, and an adequate fluidity, and a method for producing the same.SOLUTION: A high-strength steel fiber-reinforced mortar comprises cement, blast furnace slag fine powder, anhydrous gypsum, silica fume, water, sand, wollastonite, high-performance water reducing agent, antifoaming agent, and steel fiber. The high-performance water reducing agent contains 0.7-1.2 wt.% based on the weight sum of cement, blast furnace slag fine powder, anhydrous gypsum and silica fume, as well as 30-150 kg / m3 silica fume and 30-120 kg / m3 wollastonite.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a high-strength steel fiber reinforced mortar reinforced with steel fibers and a method for producing the same. [Background technology]

[0002] It has been known to add wollastonite or silica fume (Patent Document 1) or steel fibers (Patent Document 2) to reinforce high-strength mortar. It is also known that adding a large amount of a high-performance water-reducing agent or a water-reducing agent to mortar delays the setting time.

[0003] Patent Document 1 discloses a high-strength mortar consisting of cement, pozzolanic fine powder, fine aggregate, a water-reducing agent, water, and a shrinkage-reducing agent, in which the pozzolanic fine powder is silica fume or silica dust, and the shrinkage-reducing agent is mainly composed of a specific compound. Patent Document 2 discloses a high-strength mortar consisting of cement, calcium aluminate, gypsum, a setting adjuster, and a tensile strength of 1,000 N / mm 2 An ultra-rapid hardening cement composition containing the above steel fibers is disclosed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-181004 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-320834 Summary of the Invention [Problem to be solved by the invention]

[0005] It is known that in high-strength mortar, the amount of high-performance water-reducing agent or water-reducing agent added can be changed to adjust the setting time. However, when wollastonite is also added, the appropriate range of the amount of high-performance water-reducing agent and wollastonite to be added is unknown, and it is not clear how the setting time can be adjusted by such additives.

[0006] In addition, high-strength fiber-reinforced mortar in the 100-120N class is prone to material separation due to the low viscosity of the powdered additives, and may be impossible to mix depending on the blending ratio of each ingredient. Furthermore, since appropriate fluidity (flow value) is required, it is required that each additive be added in an appropriate range so that the mortar can be mixed, there is little material separation, and the appropriate fluidity (flow value) can be obtained.

[0007] In view of the problems of the prior art as described above, the present invention aims to provide a high-strength fiber-reinforced mortar that allows adjustment of the setting time and / or initial setting time, has little material separation, is kneadable, and has appropriate fluidity, and a method for producing the same. [Means for solving the problem]

[0008] The high-strength steel fiber reinforced mortar for achieving the above object is a high-strength steel fiber reinforced mortar containing cement, ground granulated blast furnace slag, anhydrous gypsum, silica fume, water, sand, wollastonite, a high-performance water reducing agent, an antifoaming agent, and steel fibers, wherein the high-performance water reducing agent is used in an amount of 0.7 to 100% by weight relative to the total weight of the cement, ground granulated blast furnace slag, anhydrous gypsum, and silica fume. 1.05 % by weight, and the silica fume is 30 to 150 kg / m 3 The wollastonite content is 30 to 120 kg / m 3 Contains.

[0009] According to this high-strength steel fiber reinforced mortar, in the high-strength steel fiber reinforced mortar containing cement, ground granulated blast furnace slag, anhydrous gypsum, silica fume, water, sand, wollastonite, a high-performance water reducing agent, a defoaming agent, and steel fibers, the high-performance water reducing agent is used in an amount of 0.7 to 1.0 times the weight of the cement, ground granulated blast furnace slag, anhydrous gypsum, and silica fume. 1.05 % by weight, silica fume content is 30-150kg / m 3 Contains wollastonite at 30-120kg / m 3 By including these additives, it is possible to adjust the setting time and / or initial setting time, achieve an appropriate flow value, and knead with little or no material separation. That is, when the contents of the high-range water reducer (SP) and silica fume (SF) are below their respective upper limits and the content of the wollastonite (WA) is above their respective lower limits, material separation does not become significant and a flow value of less than 380 mm can be achieved. Furthermore, when the contents of the high-range water reducer (SP) and silica fume (SF) are above their respective lower limits and the content of the wollastonite (WA) is below their respective upper limits, material separation does not occur, and there is little, if any, material separation, and kneading is possible.

[0010] In the high-strength steel fiber reinforced mortar, the high-performance water reducing agent is contained in an amount of 0.75 to 1.05% by weight based on the total weight, and the silica fume is contained in an amount of 58 to 115 kg / m 3 The wollastonite content is 44 to 102 kg / m 3 It is preferable that it contains

[0011] In the above high-strength steel fiber reinforced mortar, the compressive strength at 28 days is at least 100N / mm 2 is.

[0012] A method for producing high-strength steel fiber reinforced mortar for achieving the above object is a method for producing high-strength steel fiber reinforced mortar by mixing cement, ground granulated blast furnace slag, anhydrous gypsum, silica fume, water, sand, wollastonite, a high-performance water reducing agent, an antifoaming agent, and steel fibers, wherein the content of the high-performance water reducing agent is 0.7 to 1.0 parts by weight based on the total weight of the cement, ground granulated blast furnace slag, anhydrous gypsum, and silica fume. 1.05 % by weight, and the content of the silica fume is 30 to 150 kg / m 3 and the content of the wollastonite is in the range of 30 to 120 kg / m 3 The mixture is adjusted within the ranges specified above and kneaded.

[0013] According to this method for producing high-strength steel fiber reinforced mortar, cement, ground granulated blast furnace slag, anhydrous gypsum, silica fume, water, sand, wollastonite, a high-performance water reducing agent, an antifoaming agent, and steel fibers are mixed together, and the content of the high-performance water reducing agent is adjusted to 0.7 to 1.0 parts by weight based on the total weight of the cement, ground granulated blast furnace slag, anhydrous gypsum, and silica fume. 1.05 The silica fume content is within the range of 30-150 kg / m 3 and wollastonite content is within the range of 30 to 120 kg / m 3 By adjusting the temperature and / or the initial setting time within the ranges, it is possible to adjust the setting time and / or the initial setting time, to obtain an appropriate flow value, and to knead the mixture with little or no material separation.

[0014] In the method for producing high-strength steel fiber reinforced mortar, the content of the high-performance water reducing agent is set to a range of 0.75 to 1.05% by weight based on the total weight, and the content of the silica fume is set to a range of 58 to 115 kg / m 3 and the content of the wollastonite is within the range of 44 to 102 kg / m 3 It is preferable to adjust the amount of each component within the ranges given above and knead the components.

[0015] In the method for producing high-strength steel fiber reinforced mortar, 、By adjusting the content of each of the silica fume and kneading, it is possible to adjust at least one of the setting time, initial setting time, and flow value. Specifically, it is possible to adjust the delay of setting time and initial setting time, and the flow value can be adjusted to less than 380 mm, which does not cause significant material separation. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a high-strength fiber-reinforced mortar that allows adjustment of the setting time and / or initial setting time, has little material separation, is kneadable, and has appropriate fluidity, and a method for producing the same. [Brief explanation of the drawings]

[0017] [Figure 1] 4 is a bar graph showing each flow value of the test results in Table 3. [Figure 2] This figure shows the initial and final setting times of the test results in Table 3 for (a) a case where the mixing ratio of wollastonite (WA) was changed, (b) a case where the mixing ratio of silica fume (SF) was changed, and (c) a case where the mixing ratio of high-performance water-reducing agent (SP) was changed. [Figure 3] FIG. 10 is a diagram showing the relationship between the flow value and the initial time of condensation in the test results of the examples. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described. The high-strength steel fiber reinforced mortar according to this embodiment comprises cement (C), ground granulated blast furnace slag (BF), anhydrous gypsum (AG), silica fume (SF), water (W), sand (S), wollastonite (WA), a superplasticizer (SP), an antifoaming agent, and steel fibers. The superplasticizer (SP) is present in an amount of 0.7 to 1.0% by weight (SP / B) relative to the weight sum (B) of the cement (C), ground granulated blast furnace slag (BF), anhydrous gypsum (AG), and silica fume (SF). 1.05 % by weight, silica fume (SF) content is 30-150 kg / m 3The high strength steel fiber reinforced mortar contains 30 to 120 kg / m3 of wollastonite (WA). 2 It is possible to achieve a compressive strength of 28 days.

[0019] The type of cement is not particularly limited, and examples that can be used include ordinary Portland cement, early-strength Portland cement, moderate-heat Portland cement, low-heat Portland cement, and ecocement. Ground granulated blast furnace slag is a by-product produced when producing pig iron in a blast furnace, and has latent hydraulic properties that react in the presence of an alkaline stimulant. The fineness of the blast furnace slag is not particularly limited, but from the viewpoint of the strength and fluidity of the mortar, the Blaine specific surface area should be 3,000 to 10,000 cm. 2 / g is desirable. Water can be selected appropriately from those that do not affect the hydration of cement or the fluidity or strength development of the mortar. Examples include tap water, treated sewage water, and ready-mixed concrete supernatant. The type of sand is not particularly limited, and examples that can be used include silica sand, river sand, sea sand, beach sand, mountain sand, and crushed sand.

[0020] Silica fume (SF) consists of ultrafine particles of silicon dioxide, and is added to increase strength by increasing flow value through the ball-bearing effect, densifying through the pozzolanic reaction, and filling gaps with the filler effect of the ultrafine powder. As the particles are spherical, improvements in fresh properties can be expected, especially in mixes with a low water-to-binder ratio. The amount of silica fume added to this high-strength mortar is 30 to 150 kg / m. 3 30 kg / m is preferable. 3 If it is less than this, mixing becomes difficult, and the maximum is 150 kg / m 3 If the mixing rate exceeds this, the separation of the materials after mixing will become significant. 3 is.

[0021] Wollastonite (WA) is a micro-level mineral fiber, and is added to increase viscosity and tensile strength due to its needle-like particles. The blending amount of wollastonite is 30 to 120 kg / m3 30 kg / m is preferable. 3 Below 120 kg / m, material separation becomes significant. 3 If the viscosity exceeds this, the fluidity decreases and kneading becomes difficult. 3 is.

[0022] Anhydrous gypsum (AG) is added as an alkaline activator to ground granulated blast furnace slag (BF). There are no particular restrictions on the fineness of the anhydrous gypsum, but from the viewpoint of strength development and fluidity, a Blaine specific surface area of ​​3,000 to 9,000 cm is recommended. 2 / g.

[0023] A superplasticizer (SP) is a chemical admixture that either significantly reduces the amount of water per unit volume required to obtain a desired slump, or significantly increases the slump without changing the amount of water per unit volume (JIS A 6204:2011). There are no particular limitations on the type of superplasticizer, and examples include polycarboxylic acid-based, naphthalenesulfonic acid-based, melaminesulfonic acid-based, and ligninsulfonic acid-based superplasticizers, and one or more of these can be used.

[0024] The amount of superplasticizer (SP) to be mixed is 0.7 to 1.0 times the weight sum of cement, ground granulated blast furnace slag, anhydrous gypsum, and silica fume. 1.05 If the content is less than 0.7% by mass, the water-reducing effect is insufficient, making mixing difficult. 1.05 If the content exceeds 0.75% by mass, the separation of the materials after mixing becomes significant. A more preferable range is 0.75 to 1.05% by weight.

[0025] The antifoaming agent is used to adjust the amount of air in the mortar after mixing. The type of the high-strength mortar in this embodiment is not particularly limited, and examples thereof include mineral oil-based, oil-based, fatty acid-based, fatty acid ester-based, oxyalkylene-based, alcohol-based, amide-based, phosphate ester-based, metal soap-based, and silicone-based antifoaming agents, and one or more of these may be used.

[0026] Steel fibers are added to improve toughness and bending strength. The diameter of the steel fibers is preferably 0.01 mm to 1.00 mm. If the diameter is smaller than 0.01 mm, the strength of the steel fibers themselves is weak, and if it exceeds 1.00 mm, the number of fibers per unit volume of mortar decreases, making it difficult to obtain the desired physical properties. The length is preferably 6 mm to 20 mm. If it is smaller than 6 mm, the bending strength improvement effect is insufficient, and if it exceeds 20 mm, fiber balls are likely to form during kneading.

[0027] The method for kneading the mortar is not particularly limited. Any commonly used mixer can be used for kneading without any problems. Examples include a twin-screw mixer, a pan mixer, an omni mixer, a tilting mixer, and a rocking mixer. The method for adding each material is not particularly limited; each material may be added individually during kneading, or several powder materials may be premixed and added to the mixer. For example, materials other than water, a high-performance water-reducing agent, and steel fiber may be premixed and added to the mixer, and then the water, high-performance water-reducing agent, and steel fiber may be added separately.

[0028] A mix example (standard mix) of high-strength steel fiber reinforced mortar according to this embodiment is shown below. Cement (C): 300 kg / m 3 , blast furnace slag powder (BF): 700 kg / m 3 , Anhydrite (AG): 58kg / m 3 Silica fume (SF): 92 kg / m 3 , Water (W): 230kg / m 3 Marina Sand (S): 844 kg / m 3 , Wollastonite (WA): 87 kg / m 3 , High-performance water reducing agent (SP): 10.4 kg / m 3 , Defoamer: 1.2 kg / m 3 , Steel fiber: 157 kg / m 3 (However, the weight of the superplasticizer (SP) is included in the weight of water (W).) The superplasticizer (SP) is contained at 0.90% by weight (SP / B = 0.90% by weight) of the weight sum (B) of cement (C), ground granulated blast furnace slag (BF), anhydrous gypsum (AG), and silica fume (SF). The water-to-binder ratio of water (W) containing the superplasticizer (SP) is preferably 15-25% of the weight sum (B), but in this example, it is approximately 20%.

[0029] According to the high-strength steel fiber reinforced mortar of this embodiment, the high-performance water reducing agent (SP) is added in an amount of (SP / B=) 0.7 to 1.0 times the weight sum (B) of cement (C), ground granulated blast furnace slag (BF), anhydrous gypsum (AG), and silica fume (SF). 1.05 Silica fume (SF) in the range of 30 to 150 kg / m 3 Within the range of 30 to 120 kg / m 3 By adjusting each within the range, the flow value can be adjusted to less than 380 mm without increasing material separation, and the setting time can be adjusted, i.e., the setting time can be delayed and / or the setting start time can be delayed.

[0030] Furthermore, when the superplasticizer (SP) and silica fume (SF) are at or below their respective upper limits and the wollastonite (WA) is at or above their respective lower limits, material separation is not significant and a flow value of less than 380 mm can be achieved. Furthermore, when the superplasticizer (SP) and silica fume (SF) are at or above their respective lower limits and the wollastonite (WA) is at or below their respective upper limits, there is little or no material separation, and mixing is possible. [Example]

[0031] The present invention will be described in detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Table 1 below shows the mix proportions of the high-strength steel fiber reinforced mortars of Examples 1 to 7 and Comparative Examples 1 to 6. Table 2 shows the test items performed on the high-strength steel fiber reinforced mortars of each mix proportion in Table 1. Table 3 shows the test results for the high-strength steel fiber reinforced mortars of each mix proportion in Table 1.

[0032] [Table 1]

[0033] [Table 2]

[0034] [Table 3]

[0035] Using Example 2 in Table 1 as the standard mix, the mixing ratios of the three materials (wollastonite (WA), high-performance water-reducing agent (SP), and silica fume (SF)) were changed to check the setting time, fluidity (flow value), and compressive strength. That is, as shown in Table 2, the relationship between the fresh properties, mortar flow, and setting time, as well as the strength characteristics, were checked. The mixing volume was 3 liters, and the test was carried out at a room temperature of 20°C. Note that the setting test cannot be measured if steel fibers are present, so the test was carried out using a mix that did not contain steel fibers. The mix names in Table 1 indicate the mixing ratios of the three materials (wollastonite (WA), high-performance water-reducing agent (SP), and silica fume (SF)).

[0036] In the test results in Table 3, "unmixable" means that the material remained in a powder state even after 10 minutes of mixing. Also, "separation of materials" means that the steel fibers were visually confirmed to have settled.

[0037] Figure 1 shows the flow values ​​in Table 3 as a bar graph. As shown in Table 3 and Figure 1, in Comparative Example 1, where no wollastonite (WA) was added, the flow value increased to 380 mm, confirming that there was significant settling of the steel fibers (material separation), whereas in Example 1, where a small amount (lower limit) of wollastonite (WA) was added, the flow value increased but was less than 380 mm, confirming that there was minimal settling of the steel fibers (material separation). Furthermore, as in Comparative Example 2, there was a tendency for kneading to become impossible when the amount of wollastonite (WA) added was increased.

[0038] In addition, when the amount of superplasticizer (SP) added was changed, as in Examples 1 to 7, SP / B was 0.7 to 1. 1.05 When 100% by weight of silica fume (SF) was added, normal kneading was possible. Furthermore, when the amount of silica fume (SF) added was varied, settling of the steel fibers (material separation) was observed when the amount added was increased, and large amounts of material separation were confirmed in Comparative Example 6, but small amounts of material separation were confirmed in Example 7. Furthermore, when a small amount of silica fume (SF) was added, it was necessary to extend the kneading time as in Example 6.

[0039] Figure 2 is a graph showing the initial and final setting times of the test results in Table 3 for (a) the wollastonite (WA) blend ratio, (b) the silica fume (SF) blend ratio, and (c) the high-performance water-reducing agent (SP) blend ratio. As shown in Figure 2(a), when a small amount of wollastonite (WA) was added (Example 1) or when no wollastonite (WA) was added (Comparative Example 1), the setting time tended to be delayed. As shown in Figure 2(b), the initial setting time tended to be delayed as the amount of silica fume (SF) added increased, but the setting time (the time from the initial setting to the final setting) tended to be shortened. As shown in Figure 2(c), the initial and final setting times were delayed and the setting time was lengthened as the amount of high-performance water-reducing agent (SP) added increased, indicating a significant effect of the amount added. Furthermore, when the amount of ground granulated blast furnace slag (BF) was increased, the initial setting time was shortened but the final setting time was lengthened.

[0040] The relationship between flow value and initial setting time is shown in Figure 3. When the amount of wollastonite (WA) and superplasticizer (SP) added was changed, a correlation was observed between flow value and initial setting time, but when the amount of silica fume (SF) added was changed, the correlation was weaker than in the case of wollastonite (WA) and superplasticizer (SP).

[0041] As for compressive strength, as shown in the test results in Table 3, no significant difference was observed in either the 7-day compressive strength or the 28-day compressive strength due to the amount of wollastonite (WA), superplasticizer (SP), or silica fume (SF) added. The 28-day compressive strength was at least 115 N / mm2 It was.

[0042] As described above, in the high-strength fiber-reinforced mortar with the blending ratio of Example 2, the setting time and flow value can be changed by changing the amount of wollastonite (WA), high-range water-reducing agent (SP), and silica fume (SF). That is, the high-range water-reducing agent (SP) is added in an amount of 0.7% by weight (B × 0.7%) to 1.05 Weight%(B× 1.05 %), and silica fume (SF) is 30-150 kg / m 3 Within this range, wollastonite (WA) is 30-120 kg / m 3 By adjusting the amount of each additive within the above range, it is possible to produce a high-strength fiber-reinforced mortar that exhibits a specified strength with the optimal setting time and / or initial setting time and flow value.

[0043] Furthermore, the high-strength steel fiber reinforced mortar of this embodiment allows for adjustment of the setting time and / or initial setting time, and has appropriate fluidity, so it is desirable to use it as a filler material between deck slabs or precast piers installed on expressways, etc., or for construction work such as repair and reinforcement work on piers and existing road bridge surfaces.

[0044] Although the embodiments and examples for carrying out the present invention have been described above, the present invention is not limited to these and various modifications are possible within the scope of the technical idea of ​​the present invention. [Industrial Applicability]

[0045] According to the present invention, a high-strength fiber-reinforced mortar that cures at room temperature can be realized, and a method for producing the same can be provided.

Claims

1. A high-strength steel fiber reinforced mortar containing cement, ground granulated blast furnace slag, anhydrous gypsum, silica fume, water, sand, wollastonite, a high-range water reducing agent, an antifoaming agent, and steel fibers, the content of the high-performance water reducing agent is 0.7 to 1.05% by weight based on the total weight of the cement, the ground granulated blast furnace slag, the anhydrous gypsum, and the silica fume; The silica fume is 30 to 150 kg / m ３ Contains The wollastonite is 30 to 120 kg / m ３ High strength steel fiber reinforced mortar containing.

2. The high-performance water-reducing agent is contained in an amount of 0.75 to 1.05% by weight based on the total weight, The silica fume is 58 to 115 kg / m ３ Contains The wollastonite is 44 to 102 kg / m ３ 2. The high-strength steel fiber reinforced mortar according to claim 1, comprising:

3. Compressive strength at 28 days is at least 100N / mm ２ 3. The high-strength steel fiber reinforced mortar according to claim 1 or 2, wherein

4. A method for producing high-strength steel fiber reinforced mortar by mixing cement, ground granulated blast furnace slag, anhydrous gypsum, silica fume, water, sand, wollastonite, a high-range water reducing agent, an antifoaming agent, and steel fibers, comprising: The content of the high-performance water reducing agent is in the range of 0.7 to 1.05% by weight based on the total weight of the cement, the ground granulated blast furnace slag, the anhydrous gypsum, and the silica fume, and the content of the silica fume is in the range of 30 to 150 kg / m ３ and the content of the wollastonite is in the range of 30 to 120 kg / m ３ A method for producing high-strength steel fiber reinforced mortar, in which the components are adjusted and mixed within the ranges specified above.

5. The content of the high-performance water reducing agent is within the range of 0.75 to 1.05% by weight based on the total weight, and the content of the silica fume is within the range of 58 to 115 kg / m ３ and the content of the wollastonite is within the range of 44 to 102 kg / m ３ 5. The method for producing high-strength steel fiber reinforced mortar according to claim 4, wherein the components are adjusted within the ranges of 1 to 4 and kneaded.

6. 6. The method for producing high-strength steel fiber reinforced mortar according to claim 4 or 5, wherein at least one of the setting time, initial setting time, and flow value is adjusted by adjusting the contents of the high-performance water reducing agent and the silica fume and kneading them.

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