Strengthening agent for cement compositions containing blast furnace slag fine powder.
The use of inorganic sulfuric acid and triethanolamine as a strength enhancer in cement compositions with blast furnace slag powder addresses the issue of delayed setting and reduced early strength, enabling efficient production by improving early-age compressive strength and reducing defects.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- FLOLIC CO LTD
- Filing Date
- 2024-12-06
- Publication Date
- 2026-06-18
Smart Images
Figure 2026099152000001 
Figure 2026099152000002 
Figure 2026099152000003
Abstract
Description
Technical Field
[0001] The present invention relates to a strength promoter for a cement composition containing fine powder of blast furnace slag.
Background Art
[0002] While promoting decarbonization throughout society, decarbonization is also an issue in concrete products, and further expanded use of concrete using fine powder of blast furnace slag is expected.
[0003] When a large amount of fine powder of blast furnace slag is used, although strength is developed as the age of the material progresses, it is described that the compressive strength at an early age tends to decrease as the replacement rate increases (Non-Patent Documents 1 and 2). When manufacturing general concrete products, after pouring concrete into a formwork, it is left for 2 hours at 20°C, and then steam curing is performed. Steam curing usually raises the temperature by about 20°C in 1 hour, maintains the temperature at a maximum temperature of 55 to 65°C for 2 to 3 hours, and then cools down. Demolding is performed after steam curing, but if the predetermined strength has not been developed at this time, demolding may become difficult. Also, if demolding is performed with insufficient strength, there is a possibility that defects or deformations may occur in the concrete product. Since the process time is directly related to the production volume, early strength development is required for concrete.
Prior Art Documents
Non-Patent Documents
[0004]
Non-Patent Document 1
Non-Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0005] As mentioned above, due to issues such as delayed setting time and strength development, the addition of large amounts of blast furnace slag powder to concrete products (for example, a replacement rate equivalent to blast furnace cement type C) is rarely practiced in reality.
[0006] The present invention aims to provide a strength enhancer that can improve the strength of blast furnace slag-containing cement compositions, particularly by exhibiting early strength development. [Means for solving the problem]
[0007] The present invention provides the following [1] to [6]. [1] A strength enhancer for cement compositions containing blast furnace slag fine powder, comprising inorganic sulfuric acid as an active ingredient. [2] A strength enhancer for blast furnace slag fine powder-containing cement composition, comprising inorganic sulfuric acid and triethanolamine as active ingredients, wherein the content of triethanolamine relative to 100 parts by mass of the total mass of inorganic sulfuric acid and triethanolamine is greater than 0 parts by mass and 8 parts by mass or less. [3] The agent according to [1] or [2], wherein the inorganic sulfuric acid is thiosulfuric acid. [4] The agent according to any one of items [1] to [3], wherein the content of the active ingredient relative to the mass of cement is 0.5 to 5.0% by mass. [5] The agent according to any one of the claims [1] to [4], wherein the cement composition containing blast furnace slag fine powder is a composition in which the content of blast furnace slag fine powder is 40 parts by mass or more per 100 parts by mass of the total mass of cement and blast furnace slag fine powder. [6] The agent according to any one of items [1] to [5], wherein the water-binding material ratio of the blast furnace slag fine powder-containing cement composition is 25 to 65%. [Effects of the Invention]
[0008] According to the present invention, the strength of the blast furnace slag-containing cement composition, particularly its early strength development, can be further enhanced. This makes it possible to suppress the occurrence of concrete defects and deformation even when demolding is performed early after steam curing, thereby shortening the process time and improving production efficiency. [Modes for carrying out the invention]
[0009] [1. Strengthening agent] The strength enhancer contains inorganic sulfuric acid as an active ingredient, and may further contain triethanolamine as an active ingredient. The active ingredients are preferably a combination of inorganic sulfuric acid and triethanolamine, or inorganic sulfuric acid alone. In other embodiments, the active ingredient preferably does not contain diethanolisopropanolamine.
[0010] [1.1 Inorganic sulfuric acid] Inorganic sulfuric acid can be any inorganic compound that contains sulfuric acid as at least part of its structure. Examples include thiosulfuric acid, sulfuric acid, sulfite, bisulfite, dithionic acid, pyrosulfuric acid, and pyrobisulfite, with thiosulfuric acid being preferred.
[0011] [1.2 Mass ratio of inorganic sulfuric acid to triethanolamine] When the strength enhancer contains triethanolamine, the amount of triethanolamine per 100 parts by mass of the total mass of inorganic sulfuric acid and triethanolamine is usually 8 parts by mass or less, and from the viewpoint of early strength development, it is preferably 7 parts by mass or less, more preferably 6 parts by mass or less, and even more preferably 5 parts by mass or less. The lower limit is not particularly limited, but for example, it is 0.1 parts by mass or more, or 0.5 parts by mass or more.
[0012] [1.3 Amount to be added to the cement composition] The amount of the active ingredient in the strength accelerator added (mass %) relative to the cement mass is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, even more preferably 1.5% by mass or more, and even more preferably 2.0% by mass or more. This allows the strength-accelerating effect to be exerted more efficiently. The upper limit is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, even more preferably 3.5% by mass or less, and even more preferably 3.0% by mass or less. This allows the effect to be exerted in proportion to the amount added. Therefore, 0.5 to 5.0% by mass is preferred, 1.0 to 4.0% by mass is preferred, 1.5 to 3.5% by mass is even more preferred, and 2.0 to 3.0% by mass is even more preferred.
[0013] [2. Cement composition containing blast furnace slag fine powder] Strength enhancers can improve the strength of cement compositions containing blast furnace slag powder by adding them to the cement composition.
[0014] [2.1 Blast furnace slag fine powder] The cement composition contains blast furnace slag fine powder. The blast furnace slag fine powder is obtained by crushing granulated blast furnace slag or by adding gypsum to it. The specific surface area of the blast furnace slag fine powder is usually 2,500 to 10,000, preferably 3,500 or more and less than 5,000 (approximately 4,000 cm²). 2 The value per g is 4000g of blast furnace slag fine powder (JIS A6206:2013). The density of blast furnace slag fine powder is 2.80 g / cm³. 3 The above is preferable (JIS A6206:2013).
[0015] [2.2 Cement] The cement composition contains cement. Examples of the cement include Portland cement (e.g., ordinary, early strength, super early strength, moderate heat, sulfate resistant, and their low-alkali forms), various blended cements (e.g., blast furnace cement (Type A, Type B, Type C), silica cement, fly ash cement), white Portland cement, alumina cement, super high early strength cement (e.g., one-clinker rapid hardening cement, two-clinker rapid hardening cement, magnesium phosphate cement), grout cement, oil well cement, low heat cement (e.g., low heat type blast furnace cement, fly ash blended low heat type blast furnace cement, belite-rich cement), ultra-high strength cement, cementitious solidifying materials, eco-cement (e.g., cement manufactured using one or more of municipal waste incineration ash and sewage sludge incineration ash as raw materials), and other known cements. Among these, Portland cement is preferred, and ordinary Portland cement (JIS R5201:2013) is more preferred in that it is the most common and versatile ordinary cement.
[0016] [2.3 Aggregate] The cement composition usually contains aggregate. The aggregate is usually a combination of fine aggregate and coarse aggregate.
[0017] - Fine Aggregate - Examples of the fine aggregate include sand, gravel, crushed stone; water-cooled slag; recycled aggregate, etc.; aggregates with relatively small particle sizes such as siliceous, argillaceous, zirconaceous, high-alumina, silicon carbide, graphite, chromium, chroma-magnesium, magnesia, etc.
[0018] - Coarse Aggregate - Examples of the coarse aggregate include sand, gravel, crushed stone; water-cooled slag; recycled aggregate, etc.; refractory aggregates such as siliceous, argillaceous, zirconaceous, high-alumina, silicon carbide, graphite, chromium, chroma-magnesium, magnesia, etc.
[0019] [2.4 Water] The cement composition may contain water. Examples include tap water, water other than tap water (river water, lake water, well water, groundwater, industrial water, etc.), and recovered water (clarified water, sludge water).
[0020] [2.5 Other ingredients] The cement composition may contain components other than those listed above. Other components include, for example, chemical admixtures. Chemical admixtures may be any admixtures for concrete or mortar that contain a chemical substance as an active ingredient. Examples of chemical admixtures include water-reducing agents, high-performance AE water-reducing agents, AE water-reducing agents, high-performance 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 function. Examples of active ingredients in chemical admixtures include polycarboxylic acids and / or their salts, carboxyl group and / or salt-containing compounds (CA agents), sulfonic acid group and / or salt-containing compounds (SA agents), and kraft lignin. Examples of CA agents include sodium polyacrylate and sodium gluconate. Examples of SA agents include sodium lignin sulfonate and naphthalene sulfonic acid.
[0021] Furthermore, other components may include known materials that can be added to cement compositions, such as fine powders like fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, calcium carbonate, limestone powder, and gypsum, in addition to chemical admixtures. These other components may be one type or a combination of two or more types.
[0022] [2.6 Content of blast furnace slag fine powder] The content of blast furnace slag fine powder relative to 100 parts by mass of cement and blast furnace slag fine powder is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 60 parts by mass or more, and even more preferably 65 parts by mass or more. This allows the effect of adding the strength accelerator to be significantly exhibited. The upper limit is not particularly limited, but for example, it is 90 parts by mass or less, 85 parts by mass or less, or 80 parts by mass or less.
[0023] [2.7 Water binding material mass ratio] In the cement composition, the water-binding material ratio (water / (cement + blast furnace slag fine powder) × 100) is preferably 25% or more, more preferably 30% or more, and even more preferably 35% or more. The upper limit is preferably 60% or less, more preferably 55% or less, and even more preferably 50% or less. Therefore, 25-60% is preferred, 30-55% is more preferred, and 35-50% is even more preferred.
[0024] [2.7 Dosage Forms] The cement composition may be liquid, gel-like, or solid (e.g., powder, granules (pellets)).
[0025] [2.8 Manufacturing method] Cement compositions containing blast furnace slag fine powder can be manufactured by adding and mixing the components of the composition, including blast furnace slag fine powder (using equipment such as a forced mixer as needed), and then performing post-processing such as crushing, drying, molding, and classification as needed. The timing of adding the strength accelerator is not particularly limited; it may be added together with other components (for example, simultaneously with a dispersant) or added later (for example, after mixing is complete).
[0026] [3. Cured body] A cement composition containing blast furnace slag powder to which a strength accelerator has been added can be used as a hardened body for structures such as buildings, roads, dams, elevated bridges, tunnels, and port facilities, as well as other building materials. [3.1 Method for manufacturing the cured body] The hardened body can be manufactured, for example, by mixing a cement composition according to conventional methods, pouring it into a mold, and allowing it to harden. The composition poured into the mold may be defoamed by adding an antifoaming agent or the like according to conventional methods. After pouring into the mold, curing is preferable to increase mechanical strength. Curing methods include, but are not limited to, standard curing, air curing, sealed curing, steam curing, and curing using an autoclave (high-temperature, high-pressure curing). The timing of curing is also not limited to, but includes, for example, immediately after hardening or after a certain period of time has passed since hardening. [Examples]
[0027] The present invention will be described below with reference to examples. These examples are merely embodiments for illustrating the present invention and are not intended to limit it.
[0028] Examples 1-4, Comparative Examples 1-9 [Materials used] The following materials were used in the preparation of the mortar (defoaming agents and accelerators will be discussed separately). Tap water (symbol W) • Ordinary Portland cement manufactured by Taiheiyo Cement Corporation (density: 3.16 g / cm³) 3 )···Symbol C • Blast furnace slag fine powder (density: 2.89 g / cm³) 3 ,4000cm 2 / g, 4000 blancs, containing gypsum) ... Symbol B • Fine aggregate (Kakegawa-produced land sand (density: 2.58 g / cm³) 3 )··Symbol S • AE Water-Reducing Agent Standard Type I (Floric Co., Ltd., SV10) • Symbol Ad
[0029] [Mortar mix design] The proportions of W, C, B, and S among the materials used were as shown in Table 1 below.
[0030] [Table 1]
[0031] An antifoaming agent (Floric Co., Ltd., DF-753) was added at a concentration of 0.001 wt% relative to the binder. The air content of the mortar was adjusted to 2.0% or less.
[0032] [Mixing mortar] The mortar was prepared by mixing the materials according to the following procedure. S / 2 + C + B + S / 2 → Low speed 10 sec. → W + SV10 → Low speed 30 sec. → Scraping → High speed 90 sec. → Measurement The ambient temperature was 20°C, the mixing volume was 1.7L, and a forced-mix mortar mixer was used for mixing.
[0033] [Aggregators used] As accelerators, aqueous solutions of the following compounds were used together with Ad in the proportions shown in Table 2 below (addition rate relative to the cement mass). Sodium thiosulfate (45% solids by mass) - Symbol C • Triethanolamine aqueous solution (90% solids by mass) • Symbol T • Diethanolisopropanolamine (85% solids by mass) • Symbol D
[0034] [Table 2]
[0035] [Test items] The following tests were conducted on each mortar, and the results are shown in Table 3.
[0036] • Mini-slump test (mini-slump flow test): This test was conducted using a mini-slump cone as specified in JIS A 1171 "Test methods for polymer cement mortar" 6.3 Slump test.
[0037] • Compressive strength: A Φ50 x 100 mm plastic mold was used. After casting, it was immediately sealed with vinyl and cured, then stored in a 20°C environment until the specified age. Compressive strength was measured at 24 hours, 3 days, and 7 days of age.
[0038] [Table 3]
[0039] Compared to the comparative example without the strength accelerator, the mortar in the example showed a significant improvement in compressive strength at 24 hours of age, and other evaluation items were also within acceptable limits. These results indicate that the strength accelerator of the present invention can increase the strength of blast furnace slag fine powder-containing cement compositions, and in particular, can improve early strength development. Therefore, even if demolding is performed early after steam curing, the occurrence of defects and deformation can be suppressed, shortening the process time and improving production efficiency.
Claims
1. A strength enhancer for cement compositions containing blast furnace slag powder, comprising inorganic sulfuric acid as an active ingredient.
2. A strength enhancer for blast furnace slag powder-containing cement compositions, comprising inorganic sulfuric acid and triethanolamine as active ingredients, wherein the triethanolamine content is greater than 0 parts by mass and less than or equal to 8 parts by mass relative to 100 parts by mass of the total mass of inorganic sulfuric acid and triethanolamine.
3. The agent according to claim 1 or 2, wherein the inorganic sulfuric acid is thiosulfuric acid.
4. The agent according to claim 1 or 2, wherein the content of the active ingredient relative to the mass of cement is 0.5 to 5.0% by mass.
5. The agent according to claim 1 or 2, wherein the blast furnace slag fine powder-containing cement composition is a composition in which the content of blast furnace slag fine powder is 40 parts by mass or more relative to 100 parts by mass of the total mass of cement and blast furnace slag fine powder.
6. The agent according to claim 1 or 2, wherein the water-binding material ratio of the blast furnace slag fine powder-containing cement composition is 25 to 65%.