Hydration heat inhibitor

Abstract

The present invention aims to provide a hydration heat inhibitor that can efficiently exert a hydration heat suppression effect. [Solution] The present invention provides a hydration heat inhibitor comprising (A) an oxycarboxylic acid compound and (B) a nitrogen-based inorganic salt compound, wherein the solid content mass ratio of components (A) and (B) is (A):(B)=50:50 to 1:99; a method for producing the hydration heat inhibitor comprising mixing a liquid containing (a) an oxycarboxylic acid compound and a liquid containing (b) a nitrogen-based inorganic salt compound; and a cement composition containing the hydration heat inhibitor, and a hardened body thereof.

Description

Technical Field

[0001] The present invention relates to a heat of hydration inhibitor, and more particularly to a heat of hydration inhibitor and a cement composition containing the same.

Background Art

[0002] Concrete hardens when cement chemically reacts with water, generating heat of hydration during this process. Depending on the cross-section of the structural member, the heat of hydration of the cement accumulates, causing an increase in the internal temperature and subsequent cooling, as well as stress generation due to surface cooling, resulting in temperature cracking, which has been a problem in the past.

[0003] For the adjustment of concrete hydration (adjustment of the setting time), accelerators and retarders are used. As typical accelerators, there are hardening accelerators mainly composed of nitrite and nitrate compounds. Hardening accelerators are mainly used in concrete construction in cold weather to promote the early development of strength and enhance the effect. Since hydration occurs earlier, the heat of hydration tends to increase. On the other hand, retarders mainly disperse cement particles through electrostatic repulsion, chelate calcium ions near the cement surface to suppress the reaction of the cement, and impart setting retardation to the concrete (Non-Patent Document 1).

[0004] Typical techniques for controlling temperature cracking are methods for suppressing the temperature rise of concrete. For example, the use of blast furnace cement, fly ash cement, and low heat cement, measures such as pipe cooling and precooling are common (for example, Non-Patent Document 2).

[0005] Techniques for suppressing temperature stress by using hardening accelerators and hardening retarders have been reported (Patent Document 1). This method involves adding a hardening retarder to the lower concrete and a hardening accelerator to the upper concrete, creating a relative difference between the Young's modulus of the lower concrete and the Young's modulus of the upper concrete, and reducing the temperature stress due to external restraint during shrinkage in a mass concrete structure.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-68256 [Non-patent literature]

[0007] [Non-Patent Document 1] Standard Specifications for Building Construction and Commentary, JASS5, Reinforced Concrete Construction, 2022, pp.260-pp.265, 2022.11 [Non-Patent Document 2] Current Status and Trends in Mass Concrete Technology, Concrete Technology Series, Japan Society of Civil Engineers, pp. 87-88, 1994.10 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, even when retarders are used, the hydration reaction that begins after the delay shows the same exothermic hydration history as when no retarder is added, so there is no effect in suppressing the heat of hydration. Furthermore, as the rate of retarder addition increases, setting is significantly delayed, so it takes a long time to reach the required strength, which becomes a problem in terms of extending the construction period. On the other hand, low-heat cement can suppress the heat of hydration simply by using it, but these cements are not distributed nationwide, and there are problems in ensuring strength at a young age. In addition, pipe cooling and pre-cooling using liquid nitrogen are effective, but economic problems remain. Moreover, the technology in Patent Document 1 requires setting the respective addition rates of hardening accelerators and hardening retarders in concrete, and it is not a technology that suppresses the temperature difference between the inside and outside that occurs in massive concrete.

[0009] The present invention aims to provide a hydration heat inhibitor that can efficiently exert a hydration heat suppression effect. [Means for solving the problem]

[0010] The present invention provides the following [1] to

[12] . [1] (A) Oxycarboxylic acid compounds, and (B) Nitrogen-based inorganic salt compounds Includes, A hydration heat inhibitor in which the solid content mass ratio of components (A) and (B) is (A):(B)=50:50 to 1:99. [2] Component (A) is the hydration heat inhibitor described in [1], which contains a gluconate. [3] Component (B) is a hydrate heat inhibitor according to [1] or [2], comprising a nitrite and / or nitrate. [4] A liquid hydration heat inhibitor as described in any one of items [1] to [3]. [5] The hydration heat inhibitor described in [4], wherein the solid content is 38 W / W% or more. [6] (a) A liquid containing an oxycarboxylic acid compound, (b) A liquid containing a nitrogen-based inorganic salt compound A method for producing a heat of hydration inhibitor according to any one of items [1] to [5], comprising mixing. The manufacturing method according to [6], wherein the mass of the oxycarboxylate contained in the liquid of [7](a) is 20 to 60% by mass relative to the total volume of the aqueous solution. The manufacturing method according to [6] or [7], wherein the mass of the nitrogen-based inorganic salt compound contained in the liquid of [8](b) is 20 to 60% by mass relative to the total volume of the aqueous solution. A cement composition containing a hydration heat inhibitor as described in any one of items [9], [1], to [5].

[10] The cement composition according to [9], wherein the content of the hydration heat inhibitor relative to the mass of cement is 0.5 to 10% by mass.

[11] The cement composition according to [9] or

[10] , wherein the water-cement mass ratio is 30 to 60%. A hardened body of a cement composition as described in any one of items

[12] , [9], to

[11] . [Effects of the Invention]

[0011] According to the present invention, the hydration heat suppression effect can be efficiently exhibited in cement compositions such as concrete. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a graph showing the results of the simple heat insulation temperature test in the examples.

Mode for Carrying Out the Invention

[0013] [1. Heat of Hydration Suppressant] The heat of hydration suppressant contains the following (A) and (B).

[0014] [1.1 (A) Oxycarboxylic Acid Compound] Examples of the oxycarboxylic acid compound include gluconic acid, glucoheptonic acid, glycolic acid, hydroxypropanoic acid (e.g., lactic acid, 3-hydroxypropanoic acid), hydroxybutyric acid (e.g., 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid), hydroxyvaleric acid (e.g., 2-hydroxyvaleric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid), glyceric acid, tartaric acid, citric acid, tartronic acid, malic acid, and citramalic acid. The oxycarboxylic acid compound may be in the form of a salt. Examples of the salt include alkali metal salts (e.g., potassium salts, sodium salts), alkaline earth metal salts (e.g., calcium salts, magnesium salts), and ammonium salts. The oxycarboxylic acid compound is preferably a gluconate, and more preferably sodium gluconate. The component (A) may be at least one nitrogen-based inorganic salt compound, or a combination of two or more.

[0015] [1.2 (B) Nitrogen-Based Inorganic Salt Compound] Examples of nitrogen-based inorganic salt compounds include nitrites and nitrates. Examples of salts include alkaline earth metals (e.g., calcium salts, magnesium salts), alkali metals (e.g., potassium salts, sodium salts), and ammonium salts. Preferred nitrogen-based inorganic salt compounds are alkali metal nitrites and alkali metal nitrates, with calcium nitrites and calcium nitrates being more preferred. Component (B) may consist of at least one nitrogen-based inorganic salt compound, or a combination of two or more. Examples of component (B) include nitrites, or a combination of nitrites and nitrates. When component (B) is a combination of nitrites and nitrates, the content ratio of nitrites to nitrates is preferably nitrite:nitrate = 20:80 to 70:30, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40.

[0016] [1.3 (A):(B)(solid mass ratio)] In the hydration heat inhibitor, the solid content mass ratio ((A):(B)) of components (A) to (B) is preferably 50:50 to 1:99, more preferably 50:50 to 5:95, even more preferably 45:55 to 5:95, and even more preferably 40:60 to 10:90. This allows for a good hydration heat inhibitory effect.

[0017] [1.4 Optional components] The hydration heat inhibitor may contain any components other than (A) and (B). Examples of optional components include one or more cement additives (for example, chemical admixtures described in the section on cement compositions) that have components other than (A) and (B) as active ingredients.

[0018] [1.5 Dosage Forms] The hydration heat inhibitor may be in solid form (e.g., powder, pellets, gel) or liquid form (solution, suspension, dispersion), but liquid form is preferred. This makes it easier to add and mix with the cement composition, thus enabling an efficient hydration heat inhibitory effect. Depending on the dosage form, the hydration heat inhibitor may contain water. Examples of water include tap water, water other than tap water (river water, lake water, well water, groundwater, industrial water, etc.), and recovered water (supernatant water, sludge water).

[0019] [1.6 Solid content] The solid content of the hydration heat inhibitor is preferably 38 w / w% or higher. This suppresses the formation of precipitates and / or sediments over time after manufacturing, and allows for good storage stability. There is no particular upper limit, but for example, it is 60 w / w% or less, 55 w / w% or less, 50 w / w% or less, or 45 w / w% or less.

[0020] [2. Method for producing hydration heat inhibitors] The above-mentioned heat of hydration inhibitor can be manufactured by mixing (A) and (B). Preferably, this can be done by a method that includes mixing a liquid containing (a) an oxycarboxylic acid compound and a liquid containing (b) a nitrogen-based inorganic salt compound. This allows for the efficient manufacture of a heat of hydration inhibitor with excellent heat of hydration inhibitory effects. The oxycarboxylic acid compound and the nitrogen-based inorganic salt compound are as described in the section describing components (A) and (B) of the heat of hydration inhibitor.

[0021] [2.1 Liquid] The liquids (a) and (b) may be solutions, suspensions, or dispersions of each compound. The concentration of each compound can be appropriately determined according to the ratio of components (A) and (B) in the hydration heat inhibitor, the solid content concentration, etc. For example, each is preferably 20-60% by mass, more preferably 25-55% by mass, and even more preferably 30-50%. The liquids (a) and (b) may also contain components other than the compounds.

[0022] [2.2 Mixing] The mixing of liquids (a) and (b) may be carried out according to conventional methods. A mixing and stirring device may be used for mixing. Temperature adjustment may be made as necessary during mixing, or the mixing may be done at room temperature (for example, about 10 to about 40°C). Optional components may be added to the mixed liquid, or to either or both of liquids (a) and (b).

[0023] The resulting liquid may be used as is as a hydration heat inhibitor, or its concentration may be adjusted by concentration, addition of water, etc. Alternatively, it may be prepared into a dosage form other than liquid, such as solid, by drying, powdering, or pulverizing.

[0024] [3. Cement Composition] The above-mentioned hydration heat inhibitor can be added to a cement composition. This effectively suppresses the hydration heat of the cement composition.

[0025] The cement composition includes at least cement and usually further includes aggregate.

[0026] [3.1 Cement] There are no particular limitations on the type of cement used. Examples include Portland cement (ordinary, rapid-hardening, ultra-rapid-hardening, moderate-heat, sulfate-resistant, and their respective low-alkali forms), various blended cements (blast furnace cement, silica cement, fly ash cement), white Portland cement, alumina cement, ultra-rapid-hardening cement (1-clinker rapid-hardening cement, 2-clinker rapid-hardening cement, magnesium phosphate cement), grout cement, oil well cement, low-heat cement (low-heat blast furnace cement, fly ash-mixed low-heat blast furnace cement, beelite-high content cement), ultra-high-strength cement, cement-based solidifying agents, and eco-cement (cement manufactured using one or more of the following as raw materials: municipal solid waste incineration ash, sewage sludge incineration ash). The cement may also contain additives such as blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, limestone powder, gypsum, and other fine powders.

[0027] [3.2 Aggregates] The aggregate may be either fine aggregate or coarse aggregate, but it is preferable to include fine aggregate. Examples of fine aggregate include sand, gravel, crushed stone; granulated slag; recycled aggregate, etc.; and aggregates with relatively small particle sizes such as silica, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromomagnesia, and magnesia. Examples of coarse aggregate include sand, gravel, crushed stone; granulated slag; recycled aggregate, etc.; and refractory aggregates such as silica, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromomagnesia, and magnesia.

[0028] [3.3 Water-cement mass ratio] The cement composition typically contains water. Examples of water are similar to those of water that can be used as a hydration heat inhibitor. The water-cement ratio (water / cement: W / C) is preferably 60% or less, and more preferably 55% or less. The effect can be obtained even if the water-cement mass ratio (water / cement) is any value. The lower limit is preferably 30% or more, more preferably 45% or more. Therefore, the water-cement mass ratio is preferably 30-60%, more preferably 35-55%.

[0029] [3.4 Content of hydration heat inhibitor] The content of the hydration heat inhibitor is usually 0.5 to 10% by mass, preferably 0.5 to 8% by mass, and more preferably 1 to 5% by mass, relative to the total amount of cement. This allows the hydration heat inhibitory effect to be exerted while maintaining the properties required of the cement composition, such as strength. Various other desirable effects are also obtained.

[0030] [3.5 Optional components] The cement composition may further contain optional components such as volcanic ash, siliceous clay, blast furnace slag powder, expansive agents, siliceous powder, limestone powder, and chemical admixtures. Examples of chemical admixtures include water-reducing agents, high-performance AE water-reducing agents, water-soluble polymers, polymer emulsions, air-entraining agents, cement wetting agents, expansive agents, waterproofing agents, retarders, thickeners, flocculants, drying shrinkage reducing agents, strength enhancers, effect enhancers, defoaming agents, other surfactants, and other chemical admixtures intended to improve concrete functionality.

[0031] Examples of chemical admixtures include polycarboxylic acids and / or their salts, compounds containing carboxyl groups and / or their salts (CA agents), and compounds containing sulfonic acid groups and / or their salts (SA agents). Examples of CA agents include sodium polyacrylate and sodium gluconate. Examples of SA agents include sodium ligninsulfonate and naphthalenesulfonic acid. The chemical admixture may be used individually or in combination of two or more types.

[0032] Examples of water-soluble polymers include polyalkylene glycols. More specifically, examples include polyethylene glycol, polypropylene glycol, polyethylene-polypropylene glycol, polyethylene-polybutylene glycol, and the like.

[0033] Examples of retarders include sugars such as glucose and sugar alcohols such as sorbitol.

[0034] Examples of hardening accelerators include chlorides such as calcium chloride, iron chloride, and magnesium chloride; thiosulfates; and formate salts such as formic acid and calcium formate.

[0035] Examples of thickening agents include hydroxypropyl methylcellulose, carboxymethylcellulose, known cellulose nanofibers, and known cellulose nanocrystals. Commercially available defoaming agents can be used. For example, "Frolic" manufactured by Frolic Co., Ltd. One example is "DF-753".

[0036] Commercially available products can be used as high-performance AE water-reducing agents. Examples include Frolic SV10, Frolic SF500S, and Frolic SF500R from Frolic Co., Ltd.

[0037] One example of a low-thixotropic adjuvant is "Frolic FBL-200" manufactured by Frolic.

[0038] There are no particular restrictions on the manufacturing method, transportation method, placement method, curing method, management method, etc., of cement materials; ordinary methods can be used.

[0039] [4. Method for producing cement composition] Cement compositions can be manufactured by mixing (kneading) the raw materials that make up the composition. One example of the mixing order is to add and mix each component all at once or sequentially. Known mixing equipment can be used for mixing.

[0040] [5. Uses of cement compositions] The cement composition can be hardened and used, for example, as concrete or mortar for building material applications. [Examples]

[0041] The present invention will be described below with reference to examples. These examples are intended to illustrate the present invention and are not intended to limit it.

[0042] [Experiment-1] Formulation stability (Test method) A predetermined aqueous solution of nitrogen-based inorganic salt compound was weighed into a glass screw-top tube, followed by a predetermined aqueous solution of oxycarboxylate-based compound. The mixture was manually shaken for 30 seconds and stored in constant temperature baths at 10°C, 20°C, and 40°C. The stability of the formulation was checked immediately after shaking and after one month. The evaluation criteria at each temperature were as follows: ○: no precipitation or separation; ×: precipitation or suspended matter occurs, or separation occurs. The overall evaluation was as follows: ○: no × evaluations; ×: one or more × evaluations (Table 2).

[0043] (Test level) For nitrogen-based inorganic salt compounds, only calcium nitrite or a mixture of calcium nitrite and calcium nitrate was used. For oxycarboxylate salts, sodium gluconate was used (Table 1). The nitrogen-based inorganic salt compounds were pre-prepared as 45% by mass aqueous solutions, and the oxycarboxylate salts as 31.5% by mass aqueous solutions.

[0044] [Table 1]

[0045] [Table 2]

[0046] In Comparative Examples 1-6, the evaluation was either "X" immediately after preparation under 10°C conditions, or "X" immediately after preparation under 20°C and 40°C conditions, or "O" immediately after preparation but "X" after one month. In contrast, the samples from Examples 1-8 received an "O" evaluation both immediately after preparation and one month after preparation under all temperature conditions (Table 2). The results of this test demonstrate that the hydration heat inhibitor of the present invention can maintain formulation stability at the ambient temperatures to which it is exposed during practical use.

[0047] [Experiment-2] (Mortar Test) (Materials used) Tsukuba City tap water (density: 1.00 g / cm³) 3 ), ordinary Portland cement (equal parts mixture of three types: Taiheiyo Cement, Ube Mitsubishi Cement, and Sumitomo Osaka Cement, density: 3.16 g / cm³) 3 ), fine aggregate (mountain sand from Kakegawa, density: 2.58 g / cm³) 3 , Water absorption rate: 1.63%, Actual area ratio: 66.1%, Coarse particle ratio: 2.60), Admixture (SV10 manufactured by Floric, JIS A 6204 AE reduced water phase standard type I type)

[0048] (Mortar mix design)

[0049] [Table 3]

[0050] (Test conditions) The ambient temperature was 20°C, a Hobart-type forced-mix mortar mixer was used, and the mixing rate was 4.0 L / batch. Half of the fine aggregate, cement, and the remaining half of the fine aggregate were added to a bowl in that order. Mixing was done at low speed for 10 seconds, water and AE water-reducing agent were added, and mixing was done at low speed for 30 seconds. After scraping, the mixture was allowed to stand for 6 minutes from the time of water addition. After standing, hydration heat inhibitors (Comparative Examples 7-9, Examples 1-8) were added, and the mixture was stirred at high speed for 30 seconds to prepare mortar samples. The AE water-reducing agent was added at 0.60% by mass relative to the cement. The mass of the added admixtures and hydration heat inhibitors was considered part of the unit water volume. An antifoaming agent (Floric DF-753 added at 0.01% relative to the cement mass) was added to adjust the air content of the mortar to 2.0% or less. Comparative Examples 1-6, which could not be liquefied in Experiment-1, were excluded from Experiment-2.

[0051] (Measurement items) Mini-slump: Mini-slump was measured using a mini-slump cone specified in JIS A 1101. Measurement times were immediately after mixing and 45 minutes after mixing (Table 4). Air content: Measured using the mass method with a 400ml steel container, referencing JIS A 1116. The theoretical density of the mortar was used for the mass method calculation. Measurements were taken immediately after mixing and 45 minutes after mixing. Compressive strength: Five specimens measuring φ5 × 10 cm were measured at ages of 5, 6, and 8 days in accordance with JIS A 1108 (Table 4). Simple Insulation Temperature: A 350g mortar sample, immediately after mixing, was embedded in a plastic bag in the center of a 25×25×30cm Styrofoam (registered trademark). The sample was sealed to eliminate any air gaps, and the core temperature of the mortar sample was measured using a thermocouple. This test did not involve complete insulation, but rather temperature history under conditions where the effect of heat dissipation was very minimal. The slope of the least squares regression line that most closely approximated the heat generation gradient of the temperature history up to 7 days of age was determined, and the pass / fail condition was that the slope was less than or equal to that of the sample without the addition of a hydration heat inhibitor (Figure 1: Results for Comparative Example 8 (No. 1 and 3), Examples 5-7 (No. 16, 19, 21)).

[0052] (Target performance) Since the addition of a hydration heat inhibitor would cause a significant decrease in slump, which would pose problems for workability, the target performance of the mortar's mini-slump was set at 5 cm or more but less than 12 cm at 0 minutes after discharge, and 5 cm or more after 45 minutes. The target performance for compressive strength was that the system with the hydration heat inhibitor added should have a compressive strength at 5 days of age that is less than or equal to the strength at 5 days of age of the system without the hydration heat inhibitor (i.e., not hydrated), and that at 6 or 7 days of age it should be equal to or greater than the strength at 5 days of age of the system without the inhibitor (Table 4). This is because the hydration heat generation is reduced and suppressed up to 5 days of age, thereby suppressing the stress in the concrete caused by the heat of hydration.

[0053] [Table 4]

[0054] In the comparative example, the mortar samples failed to meet the target performance in terms of slump, compressive strength at 5 days of age, and compressive strength at 6 or 7 days of age, whereas the mortar samples in the examples all met the target performance (Table 4). Furthermore, in the results of the simple thermal insulation test, the core temperature of the water mortar in Comparative Example 8 (No. 3) rose sharply and most rapidly immediately after the start of hydration, followed by an early rise even in the unadditiveed sample (No. 1). In contrast, in Examples 5-7 (No. 16, 19, 21), no rise was observed immediately after the start of hydration, and only a gradual temperature rise was observed from the second day onward, in the order of Examples 5, 6, and 7 (Figure 1). The gradual temperature rise is the heat of hydration necessary to achieve the minimum required demolding strength, and since the temperature rise started on the second day, such a slow onset of heat generation can lead to a reduction in thermal cracking. The other examples showed similar behavior to the examples in Figure 1. The results of this test demonstrate that the hydration heat inhibitor of the present invention can exert its hydration heat inhibitory effect without affecting the construction period, with only a slight extension of the formwork retention period of about 1 to 2 days compared to the case without the additive.

[0055] [Experiment-3] Complete Insulation Test (Materials used) Tsukuba City tap water (density: 1.00 g / cm³) 3), ordinary Portland cement (equal parts mixture of three types: Taiheiyo Cement, Ube Mitsubishi Cement, and Sumitomo Osaka Cement, density: 3.16 g / cm³) 3 ), fine aggregate (mountain sand from Kakegawa, density: 2.58 g / cm³) 3 , Water absorption rate: 1.63%, Actual area rate: 66.1%, Coarse particle rate: 2.60), Coarse aggregate (crushed hard sandstone from Ome, density: 2.65 g / cm 3 , water absorption rate: 0.65%, actual volume: 60.5%), admixture (Floric SV10, JIS A 6204 AE water-reducing phase standard type I).

[0056] (Concrete mix design) [Table 5]

[0057] (Test conditions) A forced-mix twin-screw mixer with a nominal mixing capacity of 55 L was used at an ambient temperature of 30°C. Half of the fine aggregate, cement, and the remaining half of the fine aggregate were added to the mixer in that order. After mixing for 10 seconds, water and AE water-reducing agent were added and mixed for 90 seconds, scraping was performed, and the mixture was allowed to stand. Six minutes after water was added, a hydration heat inhibitor (Example 5) was added and stirred for 30 seconds to prepare a concrete sample. The AE water-reducing agent was added at 0.60 mass% relative to the cement. The mass of the added admixtures and hydration heat inhibitor was considered part of the unit water volume. An AE agent (Floric AE-4) and an antifoaming agent (Floric DF-753) were added to adjust the amount of air to the specified level.

[0058] (Test items) Slump test: In accordance with JIS A 1101. Air volume: Complies with JIS A 1128. Concrete temperature: In accordance with JIS A 1156. Adiabatic temperature rise test: In accordance with JCI-SQA3. A 50L sample of freshly mixed concrete was divided into three layers and filled into an insulated container using a rod-shaped vibrator.

[0059] [Table 6]

[0060] Compared to a concrete sample without any additives, the concrete sample to which the hydration heat inhibitor of Example 5 was added showed a larger slump flow, and there was no difference in air content, concrete temperature, or heat generation rate (Table 6). The results of this test indicate that the hydration heat inhibitor of the present invention can impart higher fluidity than the unadded concrete, without affecting other properties.

Claims

1. (A) Oxycarboxylic acid compounds, and (B) Nitrogen-based inorganic salt compounds Includes, A hydration heat inhibitor in which the solid content mass ratio of components (A) and (B) is (A):(B) = 50:50 to 1:

99.

2. The hydration heat inhibitor according to claim 1, wherein component (A) contains a gluconate.

3. The hydration heat inhibitor according to claim 1 or 2, wherein component (B) comprises a nitrite and / or a nitrate.

4. A hydration heat inhibitor according to claim 1 or 2, which is in liquid form.

5. The hydration heat inhibitor according to claim 4, wherein the solid content is 38 w / w% or more.

6. (a) A liquid containing an oxycarboxylic acid compound, (b) A liquid containing a nitrogen-based inorganic salt compound A method for producing a heat of hydration inhibitor according to claim 1 or 2, comprising mixing.

7. The manufacturing method according to claim 6, wherein the mass of the oxycarboxylate contained in the liquid of (a) is 20 to 60% by mass relative to the total volume of the aqueous solution.

8. The manufacturing method according to claim 6, wherein the mass of the nitrogen-based inorganic salt compound contained in the liquid of (b) is 20 to 60% by mass relative to the total volume of the aqueous solution.

9. A cement composition containing the hydration heat inhibitor described in claim 1 or 2.

10. The cement composition according to claim 9, wherein the content of the hydration heat inhibitor relative to the mass of cement is 0.5 to 10% by mass.

11. The cement composition according to claim 9, wherein the water-cement mass ratio is 30 to 60%.

12. A hardened body of the cement composition according to claim 9.

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