Mortar composition and mortar

Abstract

To provide a mortar composition capable of reducing a cement content in premixed mortar to improve CO2 reduction effect, allowing a mixed mortar to have high fluidity and material separation resistance, the mortar composition being low in pyrogenicity and exhibiting high strength development.SOLUTION: A mortar composition 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; and fine aggregate. In the mortar composition, a mass ratio of the cement is 7-30 mass% based on a mass of the mortar composition, and a mass ratio of the fine aggregate is 50-74 mass% based on the mass of the mortar composition.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a mortar composition and mortar.

Background Art

[0002] In the formation of a recycling-oriented society in business activities, efforts towards carbon neutrality are becoming increasingly important worldwide. 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 the amount of carbon dioxide (CO2) emissions attributed to global warming is large.

[0003] In order to improve the CO2 reduction effect in cement-based materials such as premix mortar, it is extremely effective to reduce the amount of cement used. The unit cement amount of premix mortar is about 1000 to 1400 kg / m in high-strength type mortar designed for rich mix, about 800 to 1000 kg / m in general-purpose 1:1 mortar (cement: fine aggregate = 1:1), and about 500 to 800 kg / m in low-heat, low-shrinkage, low-strength type mortar. Generally, the unit cement amount is significantly larger compared to concrete. 3 degree, in general-purpose 1:1 mortar (cement: fine aggregate = 1:1), the unit cement amount is about 800 to 1000 kg / m 3 degree, in low-heat, low-shrinkage, low-strength type mortar, the unit cement amount is about 500 to 800 kg / m 3 degree, and it is common for the unit cement amount to be significantly larger compared to concrete.

[0004] In premix mortar, it is known to reduce the amount of cement by using cement and various pozzolanic substances in combination (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 cementitious material, it is extremely effective to reduce the amount of cement used. On the other hand, in premixed mortar, after reducing the amount of cement and replacing it with pozzolanic substances etc., when making high-fluidity mortar that satisfies 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" to be 6 to 10 seconds, it is inferior in material separation resistance and bleeding occurs, and integration with the member cannot be achieved. Furthermore, there is a risk that pumping by a grout pump cannot be easily performed. Also, in the hardened properties of such high-fluidity 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 bases etc. at the construction site due to its high functionality, but there is a problem in that heat generation due to hydration is large in terms of formulation.

[0007] Therefore, an object of the present invention is to provide a mortar composition and mortar that reduce the amount of cement in premixed mortar to improve the CO2 reduction effect, the kneaded mortar has high fluidity, excellent material separation resistance, low heat generation, and high strength development.

Means for Solving the Problems

[0008] As a result of intensive studies on the above problems, the present inventors used a binder composed of cement, two or more pozzolanic substances including at least fine blast furnace slag powder, and an expansion material, and adjusted the amount of cement and the amount of fine aggregate in the premixed mortar, thereby improving the CO2 reduction effect and obtaining a mortar composition and mortar in which the kneaded mortar has high fluidity, excellent material separation resistance, low heat generation, and high strength development.

[0009] That is, the present invention is as follows [1] to [5]. [1] A mortar composition comprising a binder composed of cement, two or more pozzolanic substances including at least blast furnace slag fine powder, and an expansive agent, and fine aggregate, wherein the mass ratio of the cement is 7 to 30% by mass based on the mass of the mortar composition, and the mass ratio of the fine aggregate is 50 to 74% by mass based on the mass of the mortar composition. [2] The mortar composition according to [1], wherein the content of the cement is 35 to 80 parts by mass with respect to 100 parts by mass of the binder. [3] The mortar composition according to [1] or [2], further comprising a foaming agent. [4] A mortar comprising the mortar composition according to [1] or [2] and water, wherein the content of the water is 5 to 20 parts by mass with respect to 100 parts by mass of the binder. [5] The mortar according to [4], wherein the flow-down time of the 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.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a mortar composition and a mortar in which the amount of cement in the premixed mortar is reduced to improve the CO2 reduction effect, the kneaded mortar has high fluidity, excellent resistance to material separation, low heat generation, and high strength development property.

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 mortar composition of this embodiment includes a binder composed of cement, two or more pozzolanic substances including at least finely divided blast furnace slag, and an expansive agent, and fine aggregate.

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

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

[0015] The mass ratio of the cement is 7 to 30% by mass based on the mass of the mortar composition. If the mass ratio of the cement is outside the above range, a decrease in fluidity and resistance to material separation, bleeding, an increase in heat generation, etc. will occur. From the viewpoint of further improving fluidity and strength development, the mass ratio of the cement is preferably 8 to 28% by mass, more preferably 12 to 25% by mass, and even more preferably 15 to 23% by mass based on the mass of the mortar composition.

[0016] The content of the 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 the cement is within the above range, more excellent fluidity and strength development can be obtained, and property changes due to temperature are also less likely to occur.

[0017] The mortar composition of this embodiment contains two or more pozzolanic substances including at least finely powdered blast furnace slag. Examples of pozzolanic substances other than finely powdered blast furnace slag include fly ash, silica fume, amorphous aluminosilicate, volcanic ash, acid clay, and activated clay. As pozzolanic substances other than finely powdered blast furnace slag, silica fume, fly ash, and amorphous aluminosilicate are preferred.

[0018] The Blaine specific surface area of the finely powdered blast furnace slag is preferably 2000 - 10000 cm 2 / g, more preferably 3000 - 9500 cm 2 / g, still more preferably 3500 - 9000 cm 2 / g, particularly preferably 4500 - 8500 cm 2 / g. If the Blaine specific surface area of the finely powdered blast furnace slag is within the above range, good fluidity is easily obtained.

[0019] The mass ratio of the finely powdered blast furnace slag is preferably 30 - 98% by mass, more preferably 40 - 90% by mass, still more preferably 45 - 80% by mass, and particularly preferably 48 - 70% by mass with respect to the mass of the pozzolanic substances. If the mass ratio of the finely powdered 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 finely powdered blast furnace slag is preferably 5 - 40 parts by mass, more preferably 8 - 35 parts by mass, still more preferably 10 - 32 parts by mass, and particularly preferably 12 - 25 parts by mass with respect to 100 parts by mass of the binder. If the content of the finely powdered blast furnace slag is within the above range, a high strength development tendency can be obtained while sufficiently reducing the amount of cement used.

[0021] The total content of cement and fine powder of 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 cement and fine powder of blast furnace slag is within the above range, high strength developability tends to be obtained while sufficiently reducing the amount of cement used.

[0022] When silica fume is included as the pozzolanic substance, the content of 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 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 substance, the content of 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 fly ash is within the above range, good fluidity is easily obtained.

[0024] When amorphous aluminosilicate is included as the pozzolanic substance, the content of 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 amorphous aluminosilicate is within the above range, good fluidity is easily obtained.

[0025] The content of the pozzolanic substance 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 substance is within the above range, high strength developability tends to be obtained while sufficiently reducing the amount of cement used.

[0026] The expansive agent can be any expansive agent as long as it is a JIS-compliant expansive agent (JIS A 6202:2008) commonly 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 product substances. The expansive agent may be used alone or in combination of two or more kinds. It is preferable to use an expansive agent having 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 the fine aggregate include silica sand, crushed sand, gypsum, limestone sand, slag aggregate, etc. As the fine aggregate, it is preferable to use aggregates such as silica sand and limestone adjusted to a particle size that does not contain coarse aggregates from among these. The fine aggregate may be used alone or in combination of two or more kinds. In this specification, the fine aggregate refers to an aggregate having a maximum particle size of 5 mm or less. Also, the aggregate having a maximum 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 material separation resistance of the mortar, the fine aggregate having a maximum particle size of 2.5 mm or less may be used.

[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 "Sieve Analysis Test Method for Aggregates". In terms of mortar, from the viewpoint that better fluidity is easily obtained and bleeding is easily suppressed, 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 mass ratio of the fine aggregate is 50 to 74% by mass based on the mass of the mortar composition. If the mass ratio of the fine aggregate is outside the above range, the resistance to material separation decreases and bleeding also occurs. From the viewpoint that fluidity and resistance to material separation are further improved and the occurrence of bleeding is easily suppressed, the mass ratio of the fine aggregate is preferably 55 to 73% by mass, more preferably 60 to 72% by mass based on the mass of the mortar composition.

[0031] 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 is easily obtained and material separation is easily suppressed during mortar preparation.

[0032] The mortar composition 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, and peroxide substances. From the viewpoint that it can foam effectively and exhibit a more stable expansion effect, aluminum powder is preferred 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 after mortar filling, and it is difficult to cause a strength reduction due to excessive expansion.

[0034] The mortar composition 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 specified in JIS A 6204:2011 "Chemical admixtures for concrete". Examples of the water reducing agent include, for example, 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 preferred. 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 when made into mortar, and the compressive strength is also easily improved.

[0036] In the mortar composition of this embodiment, various admixtures (materials) may be blended within a range that does not impair the effects of the present invention. Examples of the admixtures (materials) include, for example, gypsum, defoaming agents, waterproof agents, rust preventives, shrinkage reducing agents, thickeners, water retention agents, pigments, water repellents, efflorescence preventives, and fibers.

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

[0038] The mortar composition of this embodiment can be prepared as mortar by mixing with water, and the water content can be appropriately adjusted according to the application. From the viewpoint of being more likely to ensure fluidity, suppressing the occurrence of material separation, increasing the shrinkage of the hardened body, and reducing the initial strength development, the water content is preferably 5 to 20 parts by mass, more preferably 5.5 to 15 parts by mass, and still more preferably 6 to 10 parts by mass with respect to 100 parts by mass of the binder.

[0039] For the preparation of the mortar of this embodiment, the same kneading equipment as that for ordinary mortar compositions can be used, and it is not particularly limited. Examples of the kneading equipment include a mortar mixer, a Hobart mixer, a hand mixer, a tilting drum mixer, a twin-shaft mixer, etc.

[0040] The mortar of this embodiment preferably has a flow-down time of 6 to 10 seconds, more preferably 6.5 to 9 seconds, and still more preferably 6.8 to 8.5 seconds for the J14 funnel measured under a 20°C environment according to the "Test Method for Fluidity of Filling Mortar" of the Japan Society of Civil Engineers Standard JSCE-F 541-2013. If the flow-down time of the J14 funnel of the mortar is within the above range, the workability and filling property of the mortar will be further improved, and it will be easier to apply for filling gaps and filling into molds. Here, the "flow-down time of the J14 funnel" is the value measured immediately after remixing the mortar.

[0041] The mortar of this embodiment preferably has a flow value (0 strike) of 200 to 280 mm, more preferably 205 to 275 mm, and still more preferably 210 to 270 mm measured under a 20°C environment according to the "Physical Test Methods for Cement" JIS R 5201:2015, 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.

[0042] The mortar composition and mortar of this embodiment have low heat generation. Low heat generation refers to a final temperature rise amount obtained by the following formula of 50°C or less when the mortar composition is kneaded with water. In the case of 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 temperature cracking due to the heat of hydration. Furthermore, when used at high temperatures, the mottling of the mortar is promoted, and it may become difficult to secure 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, and 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.

[0043] The mortar of this embodiment preferably has an initial expansion rate of 0.01 to 1.0% at 7 days of age under 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 Grouting 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 becomes easier to apply to joints between concrete structures or steel structures, filling gaps or filling in formwork, cross-section reinforcement parts of existing structures, etc.

[0044] The hardened body of the mortar of this embodiment has a compressive strength at 28 days of age measured under a 20°C environment in accordance with JIS A 1108:2018 "Test Method for Compressive Strength of Concrete" of 50 to 110 N / mm 2 preferably, 60 to 100 N / mm 2 more preferably, 70 to 95 N / mm 2 still more preferably, 80 to 95 N / mm 2It is particularly preferable that the compressive strength of the cured body is within the above range, and stronger durability can be obtained.

[0045] The mortar composition and mortar of this embodiment do not undergo material separation, have high fluidity and low heat generation, and exhibit high strength development while suppressing the amount of cement used. Therefore, such mortar compositions and mortars have a small environmental load and low heat generation, and are suitable for locations with relatively thick member thicknesses or large construction volumes. More specifically, the mortar of this embodiment can be used, for example, at joints between concrete structures with relatively large cross-sections or between steel structures, for filling gaps or filling formwork, and at cross-section reinforcement locations of existing structures.

Examples

[0046] Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto. All examples were carried out under an environment of 20°C.

[0047] [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 Rapid-hardening 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]: Naphthalene sulfonic 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

[0048] [Manufacture of Mortar Composition] The raw materials were compounded at the compounding ratios shown in Table 1 and Table 2, put into a Henschel mixer, and mixed to produce a mortar composition. All the parts by mass in the table are in terms of solid content. The binder consists of cement, various pozzolanic substances, and an expansive material.

[0049] [Manufacture of Mortar] 18 kg of the prepared mortar composition and water were kneaded with a high-speed hand mixer for 90 seconds to produce mortar. The ratio of water is as shown in Table 1 and Table 2.

[0050]

Table 1

[0051]

Table 2

[0052] [Experimental Example 1] <Evaluation of Fresh Properties of Mortar> The fresh properties (fluidity, material segregation resistance, and bleeding rate) of the prepared mortar (Inventive 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 Grouting Mortar" was measured. The criteria were 6 to 10 seconds, which is the quality standard for non-shrinking mortar in the NEXCO Structure Construction Management Guidelines. In addition, the mortar was filled into a cement paste container (flow cone) of JIS R 5201:2015 "Physical Test Methods for Cement", and the table flow value (0 blows) after lifting the container was measured. The criterion was that it spreads over 250 mm or more. [Material Segregation Resistance] The prepared mortar was placed in a 10-liter container, and the separability was judged by touching the bottom of the container to check whether fine aggregate had accumulated. Those with fine aggregate sedimented and accumulated at the bottom of the container were marked as "×: material separation", 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". The index of the bleeding rate was that the bleeding resistance was evaluated as "good" with a bleeding rate of 2% or less, which is the quality standard of NEXCO structure construction management guidelines for non-shrinking mortar.

[0053] 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 was within the range of 6 to 10 seconds, and a good spread with a flow value of 250 mm or more was confirmed. In addition, for the products of the present invention, no occurrence of aggregate separation or bleeding was observed, and it was confirmed that they had sufficient material separation resistance and high fluidity that enabled easy pumping. 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.

[0054]

Table 3

[0055] [Experimental Example 2] <Evaluation 1 of Hardening Properties of Mortar> The expansion and shrinkage 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 shrinkage rate〕 According to the Japan Society of Civil Engineers standard JSCE-F542-2013 "Test Method for Bleeding Rate and Expansion Rate of Filling Mortar", the initial expansion rate at the age of 7 days was measured. Non-shrinkage was indicated by an expansion and shrinkage rate of 0.01 to 1.0% at the age of 7 days. 〔Compressive strength〕 In accordance with JIS A 1108:2018 "Test Method for Compressive Strength of Concrete", the compressive strength at 28 days of age was measured. The dimensions of the specimens were 50 mm in diameter and 100 mm in height.

[0056] Table 4 shows the evaluation results of the expansion and shrinkage rate and compressive strength in an environment of 20°C. For all the products of the present invention, the compressive strength at 28 days of age was 70 N / mm 2 or higher, and it had appropriate expansibility and was confirmed to be non-shrinking. On the other hand, for the reference products, the compressive strength at 28 days of age was low, and some were found not to be non-shrinking.

[0057] [Table 4]

[0058] [Experimental Example 3] <Evaluation of Hardening Properties of Mortar 2> For the products 1 and 2 of the present invention and the reference products 4 and 5, the heat generation property was measured and evaluated. Each evaluation test method is shown below. [Heat Generation Property] Immediately after remixing, the mortar was filled into a simple heat-insulating container made of expanded polystyrene (capacity 3.2 L) in an environment of 20°C, covered and sealed, and the temperature history of the central part of the internal mortar was measured with a thermocouple to measure the simple heat-insulating temperature rise. The heat generation property was evaluated by the final temperature rise amount calculated from the following formula. Δt = T max - T0 T0: Temperature after mixing, T max : Maximum temperature, Δt: Final temperature rise amount

[0059] Table 5 shows the evaluation results of the heat generation property. For both products 1 and 2 of the present invention, the final temperature rise amount was a temperature rise amount of 40°C or less, and low heat generation property was confirmed. On the other hand, for the reference products, the final temperature rise amount was 50°C or more, and the heat generation property was high.

[0060] [Table 5]

Claims

1. A mortar composition comprising a binder composed of cement, two or more pozzolanic substances including at least finely ground blast furnace slag, and an expansive agent, and fine aggregate, wherein the mass ratio of the cement is 7 to 30% by mass based on the mass of the mortar composition, and the mass ratio of the fine aggregate is 50 to 74% by mass based on the mass of the mortar composition.

2. The mortar composition according to claim 1, wherein the content of the cement is 35 to 80 parts by mass based on 100 parts by mass of the binder.

3. The mortar composition according to claim 1 or 2, further comprising a foaming agent.

4. A mortar comprising the mortar composition according to claim 1 or 2 and water, wherein the content of the water is 5 to 20 parts by mass based on 100 parts by mass of the binder.

5. The mortar according to claim 4, wherein 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 Filling Mortar" is 6 to 10 seconds.

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