Highly flowable mortar

Abstract

To provide a highly flowable mortar capable of reducing a cement content in premixed mortar to improve CO2 reduction effect, having high fluidity and material separation resistance, being low in pyrogenicity and exhibiting high strength development.SOLUTION: A highly flowable mortar includes: a binding material including cement, two or more kinds of pozzolan materials including at least a blast furnace slag fine powder, and an expansive material; fine aggregate; and water. A unit quantity of the cement is 250-500 kg / m3. A unit quantity of the water is 200-300 kg / m3. A flow-down time of a J14 funnel is 6-10 seconds measured in a 20°C environment in accordance with Japan Society of Civil Engineers Standard JSCE-F 541-2013, Fluidity Test Method of Infilling Mortar.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to high-fluidity mortar.

Background Art

[0002] In the formation of a circular society in corporate activities, efforts towards carbon neutrality are increasing in importance globally. Also, in order to globally suppress global warming, through international agreements such as the Kyoto Protocol, many countries have pledged to reduce the emissions of various greenhouse gases including CO2. Against such a background, the cement used in premix mortar is manufactured by firing at a high temperature of 1400 °C using limestone as the main raw material, and thus has a large amount of carbon dioxide (CO2) emissions attributed to global warming.

[0003] In order to improve the CO2 reduction effect in premix mortar, which is a cement-based material, it is extremely effective to reduce the amount of cement used. The unit cement amount of premix mortar is about 1000 - 1400 kg / m in high-strength type mortar designed for rich mix, about 800 - 1000 kg / m in general-purpose 1:1 mortar (cement: fine aggregate = 1:1), and about 500 - 800 kg / m in low-heat, low-shrinkage, low-strength type mortar. Generally, the unit cement amount is significantly larger compared to concrete. 3 In premix mortar, a combination of cement and various pozzolanic substances to reduce the amount of cement is known (for example, Patent Document 1). 3 In premix mortar, a combination of cement and various pozzolanic substances to reduce the amount of cement is known (for example, Patent Document 1). 3 In premix mortar, a combination of cement and various pozzolanic substances to reduce the amount of cement is known (for example, Patent Document 1).

[0004] In premix mortar, a combination of cement and various pozzolanic substances to reduce the amount of cement is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In order to improve the CO2 reduction effect in premixed mortar, which is a cement-based material, it is extremely effective to reduce the amount of cement used. On the other hand, when the amount of cement in premixed mortar is reduced and replaced with pozzolanic substances or the like, and the flow-down time of the J14 funnel in the Japan Society of Civil Engineers Standard JSCE-F 541-1999 "Test Method for Fluidity of Filling Mortar" is made to satisfy 6 to 10 seconds to obtain a highly fluid mortar, the material separation resistance is inferior, bleeding occurs, integration with the member cannot be achieved, and there is a risk that pumping by a grout pump cannot be easily performed. Further, in the hardened properties of such a highly fluid mortar, there is a risk that sufficient strength development cannot be ensured, shrinkage during hardening increases, etc. When coarse aggregate is blended to eliminate the above-mentioned drawbacks of premixed mortar, sufficient fluidity cannot be obtained and material separation etc. are likely to occur. Non-shrinking mortar is used as a filling material for installation of machine foundations etc. at construction sites because of its high functionality, but there is a problem that the heat generation due to hydration is large in terms of formulation.

[0007] Therefore, an object of the present invention is to provide a highly fluid mortar that reduces the amount of cement in premixed mortar to improve the CO2 reduction effect, has a high fluidity that satisfies the flow-down time of 6 to 10 seconds of the J14 funnel in the Japan Society of Civil Engineers Standard JSCE-F 541-1999 "Test Method for Fluidity of Filling Mortar", which is a high fluidity index of non-shrinking mortar, is excellent in material separation resistance, has low heat generation, and exhibits high strength development.

Means for Solving the Problems

[0008] As a result of intensive studies on the above problems, the present inventors have found that by using a binder composed of cement, two or more pozzolanic substances including at least finely powdered blast furnace slag, and an expansion agent, and adjusting the unit amounts of cement and water in the premixed mortar, the CO2 reduction effect can be improved, and a highly fluid mortar can be obtained that has high fluidity, excellent resistance to material separation, low heat generation, and high strength development characteristics.

[0009] That is, the present invention is as follows [1] to [5]. [1] A highly fluid mortar comprising a binder composed of cement, two or more pozzolanic substances including at least finely powdered blast furnace slag, and an expansion agent, fine aggregate, and water, wherein the unit amount of the cement is 250 to 500 kg / m 3 and the unit amount of the water is 200 to 300 kg / m 3 and the flow-down time of a J14 funnel, measured in an environment at 20°C in accordance with the Japan Society of Civil Engineers Standard JSCE-F 541-2013 "Test Method for Fluidity of Grout Mortar", is 6 to 10 seconds. [2] The highly fluid mortar according to [1], wherein the total content of the cement and the finely powdered blast furnace slag is 65 to 95 parts by mass with respect to 100 parts by mass of the binder. [3] The highly fluid mortar according to [1] or [2], wherein the compressive strength at 28 days of age, measured in an environment at 20°C in accordance with JIS A 1108:2018 "Test Method for Compressive Strength of Concrete", is 50 N / mm 2 or more. [4] The highly fluid mortar according to [1] or [2], further comprising a foaming agent. [5] The highly fluid mortar according to [4], wherein the initial expansion ratio at 7 days of age, measured in an environment at 20°C in accordance with the Japan Society of Civil Engineers Standard JSCE-F542-2013 "Test Method for Bleeding Ratio and Expansion Ratio of Grout Mortar", is 0.01 to 1.0%. [Advantages of the Invention]

[0010] According to the present invention, the amount of cement in the premixed mortar is reduced to improve the CO2 reduction effect, and the kneaded mortar satisfies the falling time of 6 to 10 seconds of the J14 funnel in the Japan Society of Civil Engineers Standard JSCE-F 541-2013 "Test Method for Fluidity of Grouting Mortar", which is a high fluidity index of non-shrinking mortar, has excellent resistance to material separation, low heat generation, and high strength development ability, and a high fluidity mortar can be provided.

Embodiments for Carrying out the Invention

[0011] Hereinafter, a preferred embodiment of the present invention will be described. Regarding the description of the content in this specification, it is in terms of solid content conversion and anhydride conversion, and for those containing liquids, the moisture contained therein is included in the water content.

[0012] The high fluidity mortar of this embodiment contains a binder composed of cement, two or more kinds of pozzolanic substances including at least fine blast furnace slag powder, and an expansion agent, fine aggregate, and water.

[0013] The binder according to this embodiment is composed of cement, two or more kinds of pozzolanic substances including at least fine blast furnace slag powder, and an expansion agent.

[0014] Various cements can be used. For example, various Portland cements such as ordinary, early strength, ultra-early strength, low heat, and medium heat, eco-cement, super rapid hardening cement, fly ash cement, etc. can be mentioned. As the cement, ordinary Portland cement and early strength Portland cement are preferred. The cement may be used alone or in combination of two or more kinds.

[0015] The unit amount of cement is 250 to 500 kg / m 3It is so. If the unit amount of cement is outside the above range, a decrease in fluidity and resistance to material separation, bleeding, an increase in heat generation, a decrease in working time, a decrease in strength development, etc. will occur. From the viewpoint of obtaining even better fluidity and strength development, ensuring the working time easily, and hardly causing property changes due to temperature, the unit amount of cement is 300 to 480 kg / m 3 is preferably, 350 to 450 kg / m 3 is more preferably, 380 to 420 kg / m 3 is even more preferably.

[0016] The content of cement is preferably 35 to 80 parts by mass, more preferably 45 to 75 parts by mass, even more preferably 50 to 72 parts by mass, and particularly preferably 55 to 68 parts by mass with respect to 100 parts by mass of the binder. If the content of cement is within the above range, even better fluidity and strength development can be obtained, and property changes due to temperature hardly occur.

[0017] The high-fluidity mortar of this embodiment contains two or more kinds of pozzolanic substances including at least blast furnace slag fine powder. Examples of pozzolanic substances other than blast furnace slag fine powder include fly ash, silica fume, amorphous aluminosilicate, volcanic ash, acid clay, and activated clay. As pozzolanic substances other than blast furnace slag fine powder, silica fume, fly ash, and amorphous aluminosilicate are preferable.

[0018] The Blaine specific surface area of the blast furnace slag fine powder is preferably 2000 to 10000 cm 2 / g, more preferably 3000 to 9500 cm 2 / g, even more preferably 3500 to 9000 cm 2 / g, and particularly preferably 4500 to 8500 cm 2 / g. If the Blaine specific surface area of the blast furnace slag fine powder is within the above range, good fluidity can be easily obtained.

[0019] The mass ratio of the fine blast furnace slag is preferably 30 to 98% by mass, more preferably 40 to 90% by mass, still more preferably 45 to 80% by mass, and particularly preferably 48 to 70% by mass with respect to the mass of the pozzolanic material. If the mass ratio of the fine blast furnace slag is within the above range, the CO2 reduction effect can be further improved, and low heat generation and stable strength development are easily obtained.

[0020] The content of the fine blast furnace slag is preferably 5 to 40 parts by mass, more preferably 8 to 35 parts by mass, still more preferably 10 to 32 parts by mass, and particularly preferably 12 to 25 parts by mass with respect to 100 parts by mass of the binder. If the content of the fine blast furnace slag is within the above range, high strength development tends to be obtained while sufficiently reducing the amount of cement used.

[0021] The total content of the cement and the fine blast furnace slag is preferably 65 to 95 parts by mass, more preferably 70 to 90 parts by mass, and still more preferably 75 to 85 parts by mass with respect to 100 parts by mass of the binder. If the total content of the cement and the fine blast furnace slag is within the above range, high strength development tends to be obtained while sufficiently reducing the amount of cement used.

[0022] When silica fume is included as the pozzolanic material, the content of the silica fume is preferably 3 to 30 parts by mass, more preferably 4 to 25 parts by mass, still more preferably 5 to 20 parts by mass, and particularly preferably 10 to 15 parts by mass with respect to 100 parts by mass of the binder. If the content of the silica fume is within the above range, the resistance to material separation is further improved, and good fluidity is easily obtained.

[0023] When fly ash is included as the pozzolanic material, the content of the fly ash is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and still more preferably 3 to 10 parts by mass with respect to 100 parts by mass of the binder. If the content of the fly ash is within the above range, good fluidity is easily obtained.

[0024] When an amorphous aluminosilicate is included as the pozzolanic material, the content of the amorphous aluminosilicate may be 0.1 part by mass or more with respect to 100 parts by mass of the binder, preferably 20 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 5 parts by mass or less, and particularly preferably 2 parts by mass or less. If the content of the amorphous aluminosilicate is within the above range, good fluidity is likely to be obtained.

[0025] The content of the pozzolanic material is preferably 15 to 60 parts by mass, more preferably 20 to 55 parts by mass, still more preferably 25 to 50 parts by mass, and particularly preferably 27 to 40 parts by mass with respect to 100 parts by mass of the binder. If the content of the pozzolanic material is within the above range, high strength developability tends to be obtained while sufficiently reducing the amount of cement used.

[0026] Any expansive agent may be used as long as it is a JIS-compliant expansive agent (JIS A 6202:2008) generally used as an expansive agent for concrete. Examples of the expansive agent include an expansive agent mainly composed of free quicklime (quicklime-based expansive agent), an expansive agent mainly composed of ettringite (ettringite-based expansive agent), and a composite expansive agent of free quicklime and ettringite-forming substances. The expansive agent may be used alone or in combination of two or more. The expansive agent preferably has a Blaine specific surface area of 2000 to 6000 cm 2 / g.

[0027] The content of the expansive agent is preferably 0.1 to 10 parts by mass, more preferably 1 to 9 parts by mass, still more preferably 2 to 7 parts by mass, and particularly preferably 3 to 6 parts by mass with respect to 100 parts by mass of the binder. If the content of the expansive agent is within the above range, the compressive strength, dimensional change rate, etc. will be even more excellent.

[0028] Examples of fine aggregates include silica sand, crushed sand, gypsum, limestone sand, slag aggregates, etc. As the fine aggregate, it is preferable to use aggregates such as silica sand and limestone whose particle size has been adjusted to a size that does not contain coarse aggregates from among these. The fine aggregate may be used alone or in combination of two or more. In this specification, the fine aggregate refers to an aggregate with a maximum particle size of 5 mm or less. Also, the aggregate with a particle size of 5 mm or less refers to the one that passes through a 5 mm sieve when the aggregate is sieved. Further, from the viewpoint of the resistance of the mortar to material segregation, the fine aggregate may have a maximum particle size of 2.5 mm or less.

[0029] The particle size of the fine aggregate is not particularly limited and can be adjusted as appropriate. The particle size of the fine aggregate can be considered from the coarse grain ratio defined by JIS A 1102:2014 "Test Method for Sieving of Aggregates". From the viewpoint of being more likely to obtain better fluidity and being more likely to suppress bleeding, the coarse grain ratio of the fine aggregate is preferably 1 to 4, more preferably 1.5 to 3.8, and even more preferably 2 to 3.5.

[0030] The content of the fine aggregate is preferably 150 to 270 parts by mass, more preferably 160 to 250 parts by mass, and even more preferably 170 to 230 parts by mass with respect to 100 parts by mass of the binder. If the content of the fine aggregate is within the above range, better fluidity can be easily obtained and material segregation can be easily suppressed.

[0031] The unit amount of water is 200 to 300 kg / m 3 If the unit amount of water is outside the above range, a decrease in fluidity and resistance to material segregation, occurrence of bleeding, increase in exothermicity, decrease in working time, decrease in strength development, etc. will occur. From the viewpoint of obtaining even more excellent fluidity and strength development and being able to secure the working time easily, the unit amount of water is preferably 220 to 290 kg / m 3 more preferably 230 to 280 kg / m 3 even more preferably 240 to 270 kg / m 3 and even more preferably.

[0032] The highly fluid mortar of this embodiment may contain a foaming agent. The foaming agent is not particularly limited, and for example, any substance that generates gas after kneading with water may be used. Examples of the foaming agent include powders of amphoteric metals such as aluminum and zinc, peroxide substances, and the like. From the viewpoint of being able to foam effectively and exert the expansion effect more stably, aluminum powder is preferable as the foaming agent.

[0033] The content of the foaming agent is preferably 0.0001 to 0.1 part by mass, more preferably 0.0005 to 0.07 part by mass, and still more preferably 0.001 to 0.05 part by mass with respect to 100 parts by mass of the binder. If the content of the foaming agent is within the above range, shrinkage-free property can be ensured, it is easy to prevent the settlement reduction after mortar filling, and it is difficult to cause a strength reduction due to excessive expansion.

[0034] The highly fluid mortar of this embodiment may contain a water reducing agent. The water reducing agent includes a high-performance water reducing agent, a high-performance AE water reducing agent, an AE water reducing agent, and a fluidizing agent. Examples of such water reducing agents include water reducing agents defined in JIS A 6204:2011 "Chemical admixtures for concrete". Examples of the water reducing agent include polycarboxylic acid-based water reducing agents, naphthalene sulfonic acid-based water reducing agents, lignin sulfonic acid-based water reducing agents, and melamine-based water reducing agents. Among these, naphthalene sulfonic acid-based water reducing agents are preferable. The water reducing agent may be used alone or in combination of two or more.

[0035] The content of the water reducing agent is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, and still more preferably 0.5 to 1.5 parts by mass in terms of solid content with respect to 100 parts by mass of the binder. If the content of the water reducing agent is within the above range, better fluidity is easily obtained, and the compressive strength is also easily improved.

[0036] In the highly fluid mortar of this embodiment, various admixtures (materials) may be blended as long as the effects of the present invention are not impaired. Examples of the admixtures (materials) include gypsum, defoaming agents, waterproof agents, rust preventives, shrinkage reducing agents, thickening agents, water retention agents, pigments, water repellents, efflorescence preventives, and fibers.

[0037] The high-fluidity mortar of this embodiment can be prepared by mixing the above-described components using a commonly used kneading device, and the device is not particularly limited. Examples of the kneading device include a mortar mixer, a Hobart mixer, a hand mixer, a tilting drum mixer, a twin-shaft mixer, and the like.

[0038] The high-fluidity mortar of this embodiment has a flow-down time of 6 to 10 seconds for a J14 funnel when measured at 20°C in accordance with the Japan Society of Civil Engineers Standard JSCE-F 541-2013 "Test Method for Fluidity of Filling Mortar". If the flow-down time of the mortar through the J14 funnel is outside the above range, sufficient fluidity cannot be obtained and the filling property is poor. From the viewpoint that the workability and filling property of the mortar are further improved and it is easier to apply for filling gaps and filling into formwork, the flow-down time of the J14 funnel is preferably 6.5 to 9 seconds, and more preferably 6.8 to 8.5 seconds. Here, the "flow-down time of the J14 funnel" is the value measured immediately after remixing the mortar.

[0039] The high-fluidity mortar of this embodiment preferably has a flow value (0 strike) of 200 to 280 mm, more preferably 205 to 275 mm, and even more preferably 210 to 270 mm when measured at 20°C in accordance with the JIS R 5201:2015 "Physical Test Methods for Cement" 12. Flow Test. If the flow value (0 strike) of the mortar is within the above range, the workability of the mortar will be further improved.

[0040] The high-fluidity mortar of this embodiment has low heat generation. Low heat generation refers to a mortar composition in which the final temperature rise amount obtained by the following formula when kneaded with water is 50°C or less. In a mortar with a final temperature rise amount exceeding 50°C, when placed in a location with a relatively large member thickness, there is a risk of thermal cracking due to the heat of hydration. Furthermore, when used at high temperatures, the bleeding of the mortar is promoted and it may be difficult to ensure the working time. Therefore, the final temperature rise amount is preferably 40°C or less. Δt=T max -T0 In the formula, T0 is the kneading temperature, T max is the maximum temperature, and Δt is the final temperature rise amount. T0 and T max can be measured by filling the mortar immediately after remixing in a sealed container, measuring the temperature history of the central part of the internal mortar with a thermocouple or the like, and measuring the simple adiabatic temperature rise.

[0041] The high-fluidity mortar of this embodiment preferably has an initial expansion rate of 0.01 to 1.0% at 7 days of age in a 20°C environment, more preferably 0.12 to 0.8%, and still more preferably 0.15 to 0.5%, in accordance with the Japan Society of Civil Engineers standard JSCE-F542-2013 "Test Method for Bleeding Rate and Expansion Rate of Filling Mortar". If the initial expansion rate is within the above range, shrinkage-free property can be ensured, and it is less likely to generate gaps after hardening. Therefore, it is easy to apply to joints between concrete structures, joints between steel structures, filling gaps, cross-section reinforcement parts of existing structures, etc.

[0042] The hardened body of the high-fluidity mortar of this embodiment has a compressive strength of 50 to 110 N / mm 2 at 28 days of age, measured in a 20°C environment in accordance with JIS A 1108:2018 "Test Method for Compressive Strength of Concrete", preferably 2 60 to 100 N / mm 2 more preferably 2 70 to 95 N / mm, and particularly preferably 80 to 95 N / mm. If the compressive strength of the hardened body is within the above range, stronger durability can be obtained.

[0043] The high-fluidity mortar of this embodiment does not undergo material separation, has high fluidity and low heat generation, and exhibits high strength development while suppressing the amount of cement used. Therefore, such high-fluidity mortar also has a small environmental load and low heat generation, making it suitable for locations with relatively thick member thicknesses or large construction volumes. More specifically, the high-fluidity mortar of this embodiment can be used, for example, at joints between concrete structures with relatively large cross-sections and steel structures, for filling gaps and formwork, and for reinforcing cross-sections of existing structures, etc.

Examples

[0044] Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto. All examples were conducted under an environment of 20°C.

[0045] [Materials Used] Ground granulated blast-furnace slag [abbreviation P1]: Blaine specific surface area: 8003 cm 2 / g, commercially available product Pozolanic material 1 [abbreviation P2]: Silica fume, commercially available product Pozolanic material 2 [abbreviation P3]: Fly ash, commercially available product Early-strength Portland cement [abbreviation HC] Ordinary Portland cement [abbreviation NC] Expansion agent [abbreviation EX]: Quicklime-based expansion agent, Blaine specific surface area: 3205 cm 2 / g Water-reducing agent [abbreviation AD]: Naphthalenesulfonic acid-based water-reducing agent, commercially available product Foaming agent [abbreviation BL]: Aluminum powder, commercially available product Fine aggregate [abbreviation S]: Mixed sand of limestone sand and silica sand, maximum particle size 5 mm or less (coarse grain ratio 2.9) Water [abbreviation W]: Tap water

[0046] [Manufacture of Mortar Composition] The materials were blended at the blending ratios shown in Tables 1 and 2, put into a Henschel mixer, and mixed to produce a mortar composition. All parts by mass in the tables are in terms of solid content. The binder consists of cement, various pozzolanic materials, and an expansion agent.

[0047] [Manufacture of Mortar] 18 kg of the prepared mortar composition and water were kneaded with a high-speed hand mixer for 90 seconds to prepare mortar. The ratio of water is as shown in Tables 1 and 2.

[0048]

Table 1

[0049]

Table 2

[0050] [Experimental Example 1] <Evaluation of Fresh Properties of Mortar> The fresh properties (fluidity, material segregation resistance, and bleeding rate) of the prepared mortar (Invention Products 1 to 5, Reference Products 1 to 3) were measured and evaluated at 20°C (test room temperature, material temperature, and water temperature: 20°C ± 1°C). Each evaluation test method is shown below. 〔Fluidity〕 The flow-down time of the J14 funnel in the Japan Society of Civil Engineers Standard JSCE-F 541-2013 "Test Method for Fluidity of Grout Mortar" was measured. The range of 6 to 10 seconds, which is the quality standard of NEXCO Structure Construction Management Guidelines. Non-shrinking Mortar, was used as an index. As an index of workability (ensuring working time), the flow-down time was measured immediately after kneading the mortar and 30 minutes after completion of kneading. 〔Material Segregation Resistance〕 The prepared mortar was placed in a 10-liter container, and the non-segregation property was judged by checking by hand whether fine aggregate had accumulated at the bottom of the container. Those with fine aggregate sedimented and accumulated at the bottom of the container were marked as "×: Material Segregation", and those without accumulated aggregate were marked as "〇: Good". 〔Bleeding Rate〕 It was measured according to JIS A 1123:2022 "Test Method for Bleeding of Concrete". As an index of the bleeding rate, the bleeding resistance was evaluated as "Good" when the bleeding rate was 2% or less, which is the quality standard of NEXCO Structure Construction Management Guidelines. Non-shrinking Mortar.

[0051] Table 3 shows the evaluation results of the fresh properties. For all the products of the present invention, the J14 funnel flow-down time immediately after remixing and after 30 minutes was within the range of 6 to 10 seconds, good high fluidity was confirmed, and good fluidity was maintained even after 30 minutes, and it was confirmed that the working time could be ensured. In addition, for the products of the present invention, no aggregate separation or bleeding was observed, and it was confirmed that they had sufficient material resistance and high fluidity that could be easily pumped under pressure. On the other hand, for the reference products, it was confirmed that the J14 funnel flow-down time exceeded 10 seconds, and the material separation resistance was inferior due to the occurrence of aggregate separation, bleeding, etc.

[0052]

Table 3

[0053] [Experimental Example 2] <Evaluation 1 of the Hardening Properties of Mortar> The expansion and contraction rate and compressive strength in the hardening properties of the prepared mortar (Products 1 to 5 of the present invention, Reference Products 1 to 3) were measured and evaluated. The evaluation test methods are shown below. 〔Expansion and contraction rate〕 In accordance with the Japan Society of Civil Engineers Standard JSCE-F542-2013 "Test Method for Bleeding Rate and Expansion Rate of Grouting Mortar", the initial expansion rate at the age of 7 days was measured. Non-shrinkage was indicated by the expansion and contraction rate at the age of 7 days being 0.01 to 1.0%. 〔Compressive strength〕 In accordance with JIS A 1108:2018 "Test Method for Compressive Strength of Concrete", the compressive strength at the age of 28 days was measured. The dimensions of the test specimens were 50 mm in diameter and 100 mm in height.

[0054] Table 4 shows the evaluation results of the expansion and contraction rate and compressive strength in an environment of 20°C. For all the products of the present invention, the compressive strength at the age of 28 days was 80 N / mm 2 or higher, and also had appropriate expansibility and non-shrinkage was confirmed. On the other hand, for the reference products, the compressive strength at the age of 28 days was low, and some were found not to show non-shrinkage.

[0055]

Table 4

[0056] [Experimental Example 3] <Evaluation 2 of Mortar Hardening Properties> For Invention Products 1 and 2, and Reference Products 4 and 5, the exothermic property was measured and evaluated. Each evaluation test method is shown below. 〔Exothermic property〕 In a simple heat-insulated container made of expanded polystyrene (capacity 3.2 L) at 20°C, the mortar immediately after remixing was filled, covered, and sealed. The temperature history of the central part of the internal mortar was measured with a thermocouple, and the simple heat-insulated temperature rise was measured. The exothermic property was evaluated by the final temperature rise amount calculated from the following formula. Δt = T max - T0 T0: Tempering temperature, T max : Maximum temperature, Δt: Final temperature rise amount

[0057] Table 5 shows the evaluation results of the exothermic property. For both Invention Products 1 and 2, the final temperature rise amount was a temperature rise amount of 40°C or less, and low exothermic property was confirmed. On the other hand, for the reference products, the final temperature rise amount was 50°C or more, and the exothermic property was high.

[0058]

Table 5

Claims

1. A high-fluidity mortar comprising a binder composed of cement, two or more pozzolanic substances including at least finely powdered blast furnace slag, and an expansive agent, fine aggregate, and water, The unit amount of the cement is 250 to 500 kg / m ３ and The unit amount of the water is 200 to 300 kg / m ３ and and having a flow-down time of 6 to 10 seconds for a J14 funnel, measured under a 20°C environment in accordance with the Japan Society of Civil Engineers Standard JSCE-F 541-2013 "Test Method for Fluidity of Grout Mortar".

2. The high-fluidity mortar according to Claim 1, wherein the total content of the cement and the finely powdered blast furnace slag is 65 to 95 parts by mass with respect to 100 parts by mass of the binder.

3. Measured under an environment of 20°C in accordance with JIS A 1108:2018 "Method of Test for Compressive Strength of Concrete", the compressive strength at 28 days of age is 50 N / mm ２ or more, the high-fluidity mortar according to claim 1 or 2.

4. The high-fluidity mortar according to Claim 1 or 2, further comprising a foaming agent.

5. The high-fluidity mortar according to Claim 4, having an initial expansion rate of 0.01 to 1.0% at 7 days of age, measured under a 20°C environment in accordance with the Japan Society of Civil Engineers Standard JSCE-F 542-2013 "Test Method for Bleeding Rate and Expansion Rate of Grout Mortar".

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