WO2013077378A1 - Quick-hardening cement - Google Patents

Quick-hardening cement Download PDF

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Publication number
WO2013077378A1
WO2013077378A1 PCT/JP2012/080232 JP2012080232W WO2013077378A1 WO 2013077378 A1 WO2013077378 A1 WO 2013077378A1 JP 2012080232 W JP2012080232 W JP 2012080232W WO 2013077378 A1 WO2013077378 A1 WO 2013077378A1
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Prior art keywords
cement
mass
hardening
gypsum
rapid
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PCT/JP2012/080232
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French (fr)
Japanese (ja)
Inventor
朝明 西岡
泰一郎 森
章 七澤
亮悦 吉野
岩波 和英
那須 一郎
敏夫 川内
白井 健太郎
雅夫 松本
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電気化学工業株式会社
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Priority to JP2013545953A priority Critical patent/JP6147194B2/en
Publication of WO2013077378A1 publication Critical patent/WO2013077378A1/en

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    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C04B28/06Aluminous cements
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • C04B28/145Calcium sulfate hemi-hydrate with a specific crystal form
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/14Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
    • C04B28/16Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements containing anhydrite, e.g. Keene's cement
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2103/00Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/10Accelerators; Activators

Definitions

  • the present invention relates to a rapid hardening cement.
  • the quick-hardening cement is made by adding a quick-hardening material such as calcium aluminate to the cement, and is characterized in that it can exhibit high strength in a very short time compared to ordinary Portland cement. For this reason, rapid-hardening cement has been put to practical use as paste, mortar, and concrete, for example, as a repair material, a spraying material for tunnels, and an early mold release material for concrete secondary products.
  • a quick-hardening material such as calcium aluminate
  • rapid-hardening cement examples include spraying materials composed of a quick setting aid in which alkanolamine is added to calcium aluminate, calcium sulfoaluminate, or calcium aluminosilicate (Japanese Patent No.
  • the quick-hardening cement is kneaded with water using aggregates and placed. For this reason, it is necessary to maintain fluidity for a certain time required for kneading and placing.
  • the conventional rapid hardening cement has a problem that the setting and hardening time is short, and the casting time, particularly, the casting time at a low temperature of about 0 to 10 ° C. cannot be secured sufficiently.
  • a method for securing fluidity by adding a coagulation regulator such as an oxycarboxylic acid such as citric acid or a salt thereof is also known, but there is still room for improvement. is there. Therefore, an object of the present invention is to provide a quick-hardening cement in which a long setting and hardening time is secured.
  • hemihydrate gypsum (CaSO 4 ⁇ 1 / 2H 2 O) and dihydrate gypsum (CaSO 4 ⁇ 2H 2 O) is contained in the rapid-hardening cement to ensure sufficient setting and hardening time.
  • hemihydrate gypsum usually pseudo-conges, it was surprising that such a result was obtained because it was regarded as a component that should not be added to cement.
  • the present invention completed on the basis of the above knowledge is, in one aspect, (A) a cement, (B) a rapid hardening material containing calcium aluminate and anhydrous gypsum, and (C) a rapid hardening cement containing a setting modifier. (A) A rapid-hardening cement in which hemihydrate gypsum is contained in 1.4 to 2.7 parts by mass and dihydrate gypsum is contained in 2.0 to 5.4 parts by mass in 100 parts by mass of cement.
  • the cement has a weight loss of 0.25% by mass or less after drying at 90 ° C. for 20 hours.
  • the content of (A) cement in the quick setting cement is 70 to 95% by mass, and calcium aluminate and anhydrous gypsum are used as (A) cement 100. 5 to 40 parts by mass in total with respect to parts by mass, and (C) the setting modifier is 0.01 to 5% by mass with respect to the total mass of (A) cement, calcium aluminate and anhydrous gypsum.
  • the present invention is a cement paste, cement mortar, or cement concrete using the rapid hardening cement according to the present invention.
  • the gelation time at 5 ° C. is 60 minutes or more.
  • the curing time at 5 ° C. is 60 minutes or more.
  • the present invention is a cured product of the cement paste, cement mortar, or cement concrete according to the present invention.
  • the present invention is a method for using cement paste, cement mortar, or cement concrete, which comprises placing the cement paste, cement mortar, or cement concrete according to the present invention in a temperature environment of 1 to 10 ° C. .
  • the rapid hardening cement according to the present invention has a long setting and hardening time, a sufficient working time can be secured at the time of placing.
  • the quick-hardening cement according to the present invention contains cement as a base component.
  • cement there are no particular restrictions on the cement, but ordinary cement, early-strength cement, ultra-early-strength cement, moderately hot cement, sulfate-resistant cement, low-heat cement, oil well cement and other Portland cement, and blast furnace cement, fly ash cement, and silica Any of mixed cement such as cement and eco-cement can be used.
  • the cement content in the quick-setting cement is not particularly limited, but can be typically 70 to 95% by mass, and more typically 75 to 90% by mass.
  • the minerals contained in the cement Alite (3CaO ⁇ SiO 2) , Belite (2CaO ⁇ SiO 2), 3CaO ⁇ Al 2 O 3, 4CaO ⁇ Al 2 O 3 ⁇ Fe 2 O 3, hemihydrate gypsum (CaSO 4 ⁇ 1 / 2H 2 O), gypsum (CaSO 4 ⁇ 2H 2 O) , CaCO 3 , and the like.
  • the content of these minerals in the cement is not particularly limited, but typically 30 to 70 parts by mass of Alite (3CaO ⁇ SiO 2 ), assuming that the total amount of substances present in the cement is 100 parts by mass, Belite (2CaO ⁇ SiO 2) 20 to 60 parts by mass, 3CaO ⁇ Al 2 O 3 3 to 20 parts by mass, 4CaO ⁇ Al 2 O 3 ⁇ Fe 2 O 3 is 3 to 20 parts by weight, gypsum hemihydrate (CaSO 4 ⁇ 1 / 2H 2 O) is 1.4 to 2.7 parts by mass, dihydrate gypsum (CaSO 4 ⁇ 2H 2 O) is 2.0 to 5.4 parts by mass, and CaCO 3 is 0 to 7 parts by mass.
  • Alite 3CaO ⁇ SiO 2
  • Belite (2CaO ⁇ SiO 2) 10 to 30 parts by weight
  • hemihydrate Plaster (CaSO 4 ⁇ 1 / 2H 2 O) is from 1.4 to 2.4 parts by weight
  • gypsum (CaSO 4 ⁇ 2H 2 O) is from 2.0 to 4.7 parts by weight
  • CaCO 3 is 0-6 Part by mass.
  • an appropriate amount of dihydric gypsum is added to the cement during the pulverization process during cement production in order to prevent rapid setting due to a rapid hydration reaction such as 3CaO ⁇ Al 2 O 3 and to secure a stable setting time.
  • hemihydrate gypsum was not actively added because it promotes false setting of cement.
  • One feature of the present invention is that the setting and hardening time is delayed by containing a predetermined amount of hemihydrate gypsum and dihydrate gypsum in the cement in the rapid-hardening cement.
  • dihydric gypsum causes problems such as abnormal condensation when it is too small, and expansion when it is excessive, it is desirable to add it in the cement within the above-mentioned range. If hemihydrate gypsum is too small, the effect of delaying the setting and hardening time cannot be sufficiently obtained, and if too much, false setting tends to be promoted. Therefore, it is desirable to add it so as to be contained in the cement within the above-mentioned range.
  • a method of securing a predetermined amount of hemihydrate gypsum and dihydrate gypsum in cement a method of adding a predetermined amount of hemihydrate gypsum and dihydrate gypsum in a cement clinker, gypsum, etc. in a cement manufacturing process
  • gypsum is added in the pulverizing and mixing step to raise the pulverization temperature to produce hemihydrate gypsum
  • the gypsum is dried in the subsequent step of the pulverizing and mixing step to obtain hemihydrate gypsum.
  • the drying process when there is sufficient free water on the surface of the object to be dried, the object surface becomes equal, and the drying rate is constant regardless of the moisture content of the object, and the drying is further promoted. And a reduced rate drying rate area where free water replenishment from the inside of the object cannot keep up with the evaporation rate, but in the constant rate drying rate range, the moisture content after drying is in the process of decreasing, so the reduced rate drying rate It is preferable to dry to the area.
  • a method of drying to the reduced rate drying speed range there are a method of drying the cement with an air dryer, a method of increasing the pulverization temperature at the time of adding dihydrate gypsum in the pulverization process at the time of cement production, and the like.
  • Examples of the method of adding a predetermined amount include a method in which a preliminarily obtained hemihydrate gypsum and dihydrate gypsum are quantitatively supplied to a cement grinding mill or the like together with a cement clinker or the like.
  • a method of controlling the temperature of the cement grinding mill to, for example, 120 ° C. or less is necessary.
  • the temperature of the cement pulverization mill is operated at, for example, over 110 ° C. In order to control the ratio of water gypsum, it is effective to perform temperature control not exceeding 120 ° C. by water spray or the like.
  • a method of drying in the subsequent step of the pulverization and mixing step to obtain hemihydrate gypsum a method of drying cement at 100 to 80 ° C., more preferably 95 to 85 ° C. is effective. Examples of the drying method include a method of drying cement with an air dryer.
  • SO 3 As an index indicating gypsum in cement, SO 3 is used, and SO 3 is about 0.1 to 0.2% by mass in the clinker in the form of Na 2 SO 4 or the like as a circulating material during the production of the cement clinker. In addition to this, it is composed of dihydrate gypsum and hemihydrate gypsum.
  • SO 3 in the cement JIS R5210 SO 3 ⁇ 3.5% by weight in Portland cement, SO 3 ⁇ 4.0% by weight in JIS R5211 Blast furnace cement, SO 3 ⁇ 3.0% by weight in JIS R5212 silica cement, JIS In R5213 fly ash cement, SO 3 ⁇ 3.0% by mass, and in JIS R5214 ecocement, SO 3 ⁇ 4.5% by mass.
  • Calcium aluminate is a component generally used as a rapid hardening material, and is indispensable for exhibiting rapid hardening. Usually, it is a mineral obtained by synthesizing a CaO raw material, an Al 2 O 3 raw material, and optionally a SiO 2 raw material, etc., at 1,200 to 1,700 ° C. in an electric furnace or kiln and quenching. As an exemplary composition, CaO is 35 to 50% by mass, Al 2 O 3 is 40 to 55% by mass, and SiO 2 is 1 to 15% by mass.
  • Calcium aluminate can be in either crystalline or glassy form, but is preferably glassy obtained by quenching the melt with an electric furnace or the like.
  • the fineness of calcium aluminate is preferably 3,000 to 9,000 cm 2 / g in terms of Blaine value.
  • Anhydrous gypsum is also an important component as a rapid hardening material and, together with the hydration of calcium aluminate, acts to form the rapid hardening hydrate Ettringite, which is essential for the rapid hardening cement according to the present invention. It is. If the content of anhydrous gypsum is too high, abnormal expansion will occur after curing, while if it is too low, the rapid hardening performance will be insufficient. Therefore, the content is preferably 2 to 30% by weight in the rapid hardening cement. % Is more preferable.
  • the fineness of anhydrous gypsum is preferably 3,000 to 9,000 cm 2 / g in terms of Blaine value.
  • Calcium aluminate and anhydrous gypsum are added in a total amount of 5 to 40 parts by weight, more preferably 5 to 30 parts by weight, based on 100 parts by weight of cement. If the total of calcium aluminate and anhydrous gypsum is less than 5 parts by mass, it is difficult to show rapid hardening performance in which the strength for 3 hours in mortar and concrete is 20 MPa or more, and even if the amount added exceeds 40 parts by mass The rapid hardening performance, which is 3 hours strength, does not increase and tends to cause abnormal expansion after curing.
  • a coagulation adjusting agent such as carbonate and oxycarboxylic acid.
  • the carbonate include potassium carbonate, sodium carbonate, lithium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and the like.
  • oxycarboxylic acids include oxycarboxylic acids such as citric acid, tartaric acid, gluconic acid, malic acid, acetic acid, adipic acid, and succinic acid, and salts thereof.
  • the oxycarboxylate include sodium, potassium, calcium, magnesium, ammonium, and aluminum salts of the above acids, and examples include sodium citrate and sodium gluconate.
  • the setting modifier can be used alone or in combination of two or more.
  • the amount of setting modifier added is preferably 0.01 to 5% by mass, more preferably 0.05 to 2% by mass, based on the total mass of cement and rapid hardening material (calcium aluminate + anhydrous gypsum). To do. If the setting modifier is less than 0.01% by mass, sufficient gelation time cannot be secured. Even if the addition amount exceeds 5% by mass, the gelation time may be shortened. It is difficult to stably ensure a time, for example, a gelation time of 60 minutes or more.
  • ⁇ Other cement admixtures In the quick-hardening cement according to the present invention, various conventional cement admixtures can be appropriately added. For example, a water reducing agent, aggregate, etc. can be added. It is also effective to add an appropriate amount of a substance such as a pozzolanic material such as silica fume, 3CaO.3Al 2 O 3 .CaSO 4 or the like in order to impart denseness and expandability.
  • a substance such as a pozzolanic material such as silica fume, 3CaO.3Al 2 O 3 .CaSO 4 or the like in order to impart denseness and expandability.
  • the raw material cement used has a weight loss after drying at 90 ° C. for 20 hours of 0.25% by mass or less, preferably 0.2% by mass or less, More preferably, it is 0.1 mass% or less.
  • the gelation time at 5 ° C. can be lengthened, preferably 60 minutes or longer
  • the curing time at 5 ° C. can be lengthened, preferably 60 minutes or longer. can do.
  • gelation time is defined as one of the indexes for evaluating the setting and hardening characteristics of rapid-hardening cement.
  • the gelation time is determined by measuring the relationship between the time after pouring water mixing and the temperature rise for 200 g of rapid hardening cement paste (fast hardening cement 156 g + 44 g of water) at a specific ambient temperature. This is the time required for the temperature to rise.
  • the setting time is defined as one of the indexes for evaluating the setting and setting time of the rapid hardening cement.
  • the setting time is a time required for the temperature of the kneaded cement paste to rise by 5 ° C. due to the heat generated by hardening, after measuring the relationship between the time after water pouring and the temperature rise for 200 g of the rapid hardening cement paste.
  • Rapid hardening cement paste loses its fluidity with increasing temperature due to gelation and hardening. As an index for losing fluidity, it is effective to use an index that the residence time in the funnel becomes long.
  • FIGS. 1-1 and 1-2 show the setting and hardening time from the viewpoint of easy understanding. The gelation time and the setting time for the insufficiently setting rapid setting cement and the setting cement having a sufficiently long setting time are shown schematically together with an increase in temperature and a decrease in fluidity.
  • the viscosity of the rapid hardening cement paste increases, and when it hardens, the rapid hardening paste hardens, and the strength rapidly increases. After about 3 hours, the strength of the hardened mortar / concrete is increased. It exceeds 20 Mpa and is used for civil engineering structures. Specifically, the viscosity is about 800 cps immediately after kneading of the rapid hardening cement paste, but with the gelation, the viscosity of the rapid hardening cement paste exceeds 10,000 cps, kneading with a mixer, injection of the rapid hardening paste, It is difficult to secure operations such as placing and compacting.
  • the viscosity of the hardened cement paste after kneading is measured by the J-rote non-shrink mortar quality control test method (Japan Highway Public Standard JHS 312), and the funnel is KC-57 J ), Mortar flow shown in JIS R5210, rotational viscosity measurement method according to JIS Z8803 “liquid viscosity-measurement method”, and the like.
  • a rapid hardening cement paste hardens after the curing time has elapsed, and records about 1 [N / mm 2 ] according to the Procter penetration resistance test method (JIS A 6204 Annex I).
  • the gelation time and setting time are too short, construct a structure with cement concrete, etc. with the addition of aggregate (sand, gravel, etc.) to rapid hardening cement paste, or repair work with cement mortar with addition of sand, etc. It becomes impossible to ensure the work time generally performed. It is desirable that the gelation time and the curing time at 5 ° C. be sufficiently long in order to practically perform mass placement with mortar, concrete, etc. using a concrete pump or the like at a construction site in the cold season.
  • the gelation time at 5 ° C. is 60 minutes or longer, preferably 70 minutes or longer, for example 60 to 80 minutes. be able to.
  • the curing time at 5 ° C. is 60 minutes or longer, preferably 70 minutes or longer, for example 60 to 80 minutes. Can do.
  • the quick-hardening cement according to the present invention can be manufactured by mixing the above-mentioned cement, quick-hardening material, setting modifier, and the like. Then, by adding water to the rapid-hardening cement and kneading the raw materials with a general mixer, preferably a forced kneading mixer, a quick-hardening cement paste can be produced.
  • a general mixer preferably a forced kneading mixer
  • the amount is preferably 10 to 50 parts by mass with respect to 100 parts by mass of the rapid-hardening cement. It is more preferable that the amount be ⁇ 45 parts by mass, and typically 20 to 40 parts by mass.
  • the rapid-hardening cement paste according to the present invention has high workability and workability because of a long setting and hardening time. For this reason, for example, a grader, a bulldozer, a finisher or the like can be used to spread and further high strength can be obtained at an early stage by compacting and rolling with a hammer, a tire roller, a vibration roller, or the like.
  • the quick-hardening cement paste according to the present invention is particularly excellent in workability and workability in a low temperature environment, and can be suitably used for placing in a temperature environment of 1 to 10 ° C., for example.
  • the hardened cement paste according to the present invention is a hardened mortar or concrete, for example, in tunnels such as roads, railways, water conduits, etc. It can be used sometimes.
  • a powdery ordinary Portland cement (No. 1 to 4) having each composition shown in Table 1 was prepared.
  • the amount of substance in the cement is a value obtained by chemical composition analysis by Rietveld method. Specifically, the amount of each chemical component was determined from the diffraction intensity by powder X-ray diffraction using “SIROQUANT® Version 2.5” (manufactured by Sietronics).
  • Table 2 also shows the results of chemical analysis according to JIS R5202.
  • the gelation time is in the range of 50 minutes, It increased to 60 minutes and 70 minutes, and more than 50 minutes were secured.
  • the quick-hardening cement (No. 3, No. 4) according to the comparative example the gelation time is in the range from 40 minutes to 20 minutes as the curing temperature decreases to 30 ° C., 20 ° C., and 5 ° C. Especially at 5 ° C., it is remarkably short as less than 30 minutes. Also, the curing time is significantly shorter than that of the inventive examples.
  • the amount of each chemical component in the cement shown in Table 1 according to the Rietveld method is 60 to 50% by mass of Alite (3CaO ⁇ SiO 2 ) and Belite (2CaO ⁇ SiO 2 ) for any of the rapid hardening cements according to any test number. 2 ) is 20 to 10% by mass, 3CaO.Al 2 O 3 is 10 to 5% by mass, and 4CaO.Al 2 O 3 .Fe 2 O 3 is 15 to 5% by mass. There is no difference.
  • the amount of hemihydrate gypsum is as high as 1.4 to 2.2% by mass, and dihydrate gypsum is 2.4%.
  • the comparative example has a small amount of hemihydrate gypsum as 0.8 to 1.3% by mass and a dihydrate gypsum as large as 3.3 to 3.7% by mass.
  • the amount of hemihydrate gypsum is as large as 1.4 to 2.2% by mass, so that the amount of Ca and SO 4 2- in 1 to 5 minutes in the initial elution stage is high. . Therefore, Ca and SO 4 2-dissolution is promoted, usually 3CaO ⁇ Al 2 O 3 the cement contained in, 4CaO ⁇ Al 2 O 3 ⁇ Fe 2 O 3 and gypsum, and hemihydrate gypsum It is considered that the hydration of the rapid hardening admixture is suppressed by accelerating the hydration of the mixture, thereby suppressing the hydration of the rapid-hardening admixture.

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Abstract

Provided is a quick-hardening cement wherein a long setting and hardening time is ensured. A quick-hardening cement containing a cement (A), a quick-hardening material (B) containing a calcium aluminate and an anhydride gypsum, and a setting regulating agent (C), wherein 1.4 to 2.7 parts by mass of a hemihydride gypsum and 2.0 to 5.4 parts by mass of a dihydride gypsum are contained in 100 parts by mass of the cement (A).

Description

急硬性セメントRapid hardening cement
 本発明は急硬性セメントに関する。 The present invention relates to a rapid hardening cement.
 急硬性セメントは、カルシウムアルミネート等の急硬材がセメントに添加されてできたものであり、通常のポルトランドセメントに比べて極めて短時間で高い強度を発現できることを特徴としている。このため、急硬性セメントはペースト、モルタル及びコンクリートとして、例えば補修材料、トンネル用吹付材料、コンクリート二次製品の早期脱型材料等として実用に供されてきた。 The quick-hardening cement is made by adding a quick-hardening material such as calcium aluminate to the cement, and is characterized in that it can exhibit high strength in a very short time compared to ordinary Portland cement. For this reason, rapid-hardening cement has been put to practical use as paste, mortar, and concrete, for example, as a repair material, a spraying material for tunnels, and an early mold release material for concrete secondary products.
 急硬性セメントの例としては、カルシウムアルミネート、カルシウムサルホアルミネート、カルシウムアルミノシリケートにアルカノールアミンを加えた急結助剤からなる吹付け材料(特許第3412795号公報)、3CaO・3Al23・CaF2及び無機硫酸塩等を含有する超硬練りコンクリート(特開平2-180740号公報)、3CaO・SiO2固溶体と11CaO・7Al23・CaF2を含有するクリンカー、無水石膏、アルミノケイ酸カルシウムガラス等を含有する超速硬セメント組成物(特開2007-320833号公報)、C12A7(12CaO・7Al23)系にFe23、CaF2を加えた急硬性クリンカー組成物(特開平9-268037号公報)、12CaO・7Al23を主成分としたクリンカー原料に、Fe23及びCaF2を添加した急硬性クリンカー組成物(特開平6-115986号公報)等が挙げられる。 Examples of rapid-hardening cement include spraying materials composed of a quick setting aid in which alkanolamine is added to calcium aluminate, calcium sulfoaluminate, or calcium aluminosilicate (Japanese Patent No. 3412795), 3CaO · 3Al 2 O 3 · Super hard kneaded concrete containing CaF 2 and inorganic sulfate (JP-A-2-180740), clinker containing 3CaO · SiO 2 solid solution and 11CaO · 7Al 2 O 3 · CaF 2 , anhydrous gypsum, calcium aluminosilicate Super hard cement composition containing glass or the like (JP 2007-320833 A), rapid hardening clinker composition in which Fe 2 O 3 and CaF 2 are added to C12A7 (12CaO · 7Al 2 O 3 ) system -268037 discloses), Clean mainly composed of 12CaO · 7Al 2 O 3 The chromatography material, rapid hardening clinker composition with the addition of Fe 2 O 3 and CaF 2 (JP-A-6-115986 JP), and the like.
特許第3412795号公報Japanese Patent No. 3412795 特開平2-180740号公報Japanese Patent Laid-Open No. 2-180740 特開2007-320833号公報JP 2007-320833 A 特開平9-268037号公報JP-A-9-268037 特開平6-115986号公報JP-A-6-115986
 急硬性セメントは、骨材等を用い、水と混練し、打設する。このため、混練、打設に要する一定時間は流動性を保持することが必要である。この点に関して、従来の急硬性セメントにおいては、凝結硬化時間が短く、打設時間、とりわけ0~10℃程度の低温時における打設時間を十分に確保できないという問題があった。特許文献3に記載されているように、クエン酸等のオキシカルボン酸やその塩のような凝結調節剤を添加することで流動性を確保する方法も知られているが、未だ改善の余地がある。そこで、本発明は、長い凝結硬化時間が確保された急硬性セメントを提供することを課題の一つとする。 The quick-hardening cement is kneaded with water using aggregates and placed. For this reason, it is necessary to maintain fluidity for a certain time required for kneading and placing. In this regard, the conventional rapid hardening cement has a problem that the setting and hardening time is short, and the casting time, particularly, the casting time at a low temperature of about 0 to 10 ° C. cannot be secured sufficiently. As described in Patent Document 3, a method for securing fluidity by adding a coagulation regulator such as an oxycarboxylic acid such as citric acid or a salt thereof is also known, but there is still room for improvement. is there. Therefore, an object of the present invention is to provide a quick-hardening cement in which a long setting and hardening time is secured.
 本発明者は上記課題を解決するために鋭意検討したところ、石膏の水和状態が凝結硬化時間に有意に影響を与えていることを見出した。そして、急硬性セメント中に半水石膏(CaSO4・1/2H2O)及び二水石膏(CaSO4・2H2O)を所定量併用して含有させることで、十分な凝結硬化時間を確保することが可能であることを見出した。通常、半水石膏は偽凝結するため、セメント中には添加すべきでない成分とされていたことからこのような結果が得られたことは意外であった。 As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the hydration state of gypsum significantly affects the setting and hardening time. In addition, a predetermined amount of hemihydrate gypsum (CaSO 4 · 1 / 2H 2 O) and dihydrate gypsum (CaSO 4 · 2H 2 O) is contained in the rapid-hardening cement to ensure sufficient setting and hardening time. Found that it is possible to do. Since hemihydrate gypsum usually pseudo-conges, it was surprising that such a result was obtained because it was regarded as a component that should not be added to cement.
 上記の知見に基づいて完成した本発明は一側面において、(A)セメント、(B)カルシウムアルミネート及び無水石膏を含有する急硬材、(C)凝結調整剤を含有する急硬性セメントであって、(A)セメント100質量部中に半水石膏が1.4~2.7質量部、二水石膏が2.0~5.4質量部含まれる急硬性セメントである。 The present invention completed on the basis of the above knowledge is, in one aspect, (A) a cement, (B) a rapid hardening material containing calcium aluminate and anhydrous gypsum, and (C) a rapid hardening cement containing a setting modifier. (A) A rapid-hardening cement in which hemihydrate gypsum is contained in 1.4 to 2.7 parts by mass and dihydrate gypsum is contained in 2.0 to 5.4 parts by mass in 100 parts by mass of cement.
 本発明に係る急硬性セメントの一実施形態においては、半水石膏と二水石膏の質量比が半水石膏/二水石膏=0.2~1.0である。 In one embodiment of the quick-hardening cement according to the present invention, the mass ratio of hemihydrate gypsum to dihydrate gypsum is hemihydrate gypsum / dihydrate gypsum = 0.2 to 1.0.
 本発明に係る急硬性セメントの別の一実施形態においては、半水石膏と二水石膏の質量比が半水石膏/二水石膏=0.4~0.6である。 In another embodiment of the quick-hardening cement according to the present invention, the mass ratio of hemihydrate gypsum to dihydrate gypsum is hemihydrate gypsum / dihydrate gypsum = 0.4 to 0.6.
 本発明に係る急硬性セメントの別の一実施形態においては、(A)セメントは90℃で20時間乾燥後の減量分が0.25質量%以下である。 In another embodiment of the quick-hardening cement according to the present invention, (A) the cement has a weight loss of 0.25% by mass or less after drying at 90 ° C. for 20 hours.
 本発明に係る急硬性セメントの更に別の一実施形態においては、急硬性セメント中の(A)セメントの含有量が70~95質量%であり、カルシウムアルミネート及び無水石膏は(A)セメント100質量部に対して合計で5~40質量部であり、(C)凝結調整剤は、(A)セメント、カルシウムアルミネート及び無水石膏の合計質量に対して0.01~5質量%である。 In yet another embodiment of the quick setting cement according to the present invention, the content of (A) cement in the quick setting cement is 70 to 95% by mass, and calcium aluminate and anhydrous gypsum are used as (A) cement 100. 5 to 40 parts by mass in total with respect to parts by mass, and (C) the setting modifier is 0.01 to 5% by mass with respect to the total mass of (A) cement, calcium aluminate and anhydrous gypsum.
 本発明は別の一側面において、本発明に係る急硬性セメントを使用したセメントペースト、セメントモルタル又はセメントコンクリートである。 In another aspect, the present invention is a cement paste, cement mortar, or cement concrete using the rapid hardening cement according to the present invention.
 本発明に係るセメントペースト、セメントモルタル又はセメントコンクリートの一実施形態においては、5℃でのゲル化時間が60分以上である。 In one embodiment of the cement paste, cement mortar or cement concrete according to the present invention, the gelation time at 5 ° C. is 60 minutes or more.
 本発明に係るセメントペースト、セメントモルタル又はセメントコンクリートの一実施形態においては、5℃での硬化時間が60分以上である。 In one embodiment of the cement paste, cement mortar or cement concrete according to the present invention, the curing time at 5 ° C. is 60 minutes or more.
 本発明は更に別の一側面において、本発明に係るセメントペースト、セメントモルタル又はセメントコンクリートの硬化物である。 In yet another aspect, the present invention is a cured product of the cement paste, cement mortar, or cement concrete according to the present invention.
 本発明は更に別の一側面において、本発明に係るセメントペースト、セメントモルタル又はセメントコンクリートを1~10℃の温度環境で打設することを含むセメントペースト、セメントモルタル又はセメントコンクリートの使用方法である。 In yet another aspect, the present invention is a method for using cement paste, cement mortar, or cement concrete, which comprises placing the cement paste, cement mortar, or cement concrete according to the present invention in a temperature environment of 1 to 10 ° C. .
 本発明に係る急硬性セメントは凝結硬化時間が長いので、打設時に十分な作業時間を確保することができる。 Since the rapid hardening cement according to the present invention has a long setting and hardening time, a sufficient working time can be secured at the time of placing.
凝結硬化速度の正常な急硬性セメントについての、ゲル化時間及び硬化時間の模式図である。It is a schematic diagram of the gelation time and the hardening time about a rapid hardening cement with a normal setting and hardening rate. 凝結硬化速度の異常な急硬性セメントについての、ゲル化時間及び硬化時間の模式図である。It is a schematic diagram of gelation time and hardening time about a rapid hardening cement with an abnormal setting hardening rate. 実施例で行った溶出試験の結果を示す図である。It is a figure which shows the result of the elution test done in the Example.
<セメント>
 本発明に係る急硬性セメントにおいてはベース成分としてセメントを含有する。セメントとしては特に制限はないが、普通セメント、早強セメント、超早強セメント、中庸熱セメント、耐硫酸塩セメント、低熱セメント、油井セメント等のポルトランドセメント、及び高炉セメント、フライアッシュセメント、及びシリカセメント等の混合セメント、エコセメント等いずれも使用が可能である。急硬性セメント中のセメントの含有量は、特に制限はないが、典型的には70~95質量%とすることができ、より典型的には75~90質量%とすることができる。
<Cement>
The quick-hardening cement according to the present invention contains cement as a base component. There are no particular restrictions on the cement, but ordinary cement, early-strength cement, ultra-early-strength cement, moderately hot cement, sulfate-resistant cement, low-heat cement, oil well cement and other Portland cement, and blast furnace cement, fly ash cement, and silica Any of mixed cement such as cement and eco-cement can be used. The cement content in the quick-setting cement is not particularly limited, but can be typically 70 to 95% by mass, and more typically 75 to 90% by mass.
 本発明において、セメント中に含まれる鉱物としては、Alite(3CaO・SiO2)、Belite(2CaO・SiO2)、3CaO・Al23、4CaO・Al23・Fe23、半水石膏(CaSO4・1/2H2O)、二水石膏(CaSO4・2H2O)、CaCO3等が挙げられる。セメント中のこれらの鉱物の含有量は、特に制限はないが、セメント中に存在する物質の合計を100質量部とすると、典型的にはAlite(3CaO・SiO2)が30~70質量部、Belite(2CaO・SiO2)が20~60質量部、3CaO・Al23が3~20質量部、4CaO・Al23・Fe23が3~20質量部、半水石膏(CaSO4・1/2H2O)が1.4~2.7質量部、二水石膏(CaSO4・2H2O)が2.0~5.4質量部、CaCO3が0~7質量部であり、より典型的にはAlite(3CaO・SiO2)が40~65質量部、Belite(2CaO・SiO2)が10~30質量部、3CaO・Al23が5~10質量部、4CaO・Al23・Fe23が5~15質量部、半水石膏(CaSO4・1/2H2O)が1.4~2.4質量部、二水石膏(CaSO4・2H2O)が2.0~4.7質量部、CaCO3が0~6質量部である。 In the present invention, the minerals contained in the cement, Alite (3CaO · SiO 2) , Belite (2CaO · SiO 2), 3CaO · Al 2 O 3, 4CaO · Al 2 O 3 · Fe 2 O 3, hemihydrate gypsum (CaSO 4 · 1 / 2H 2 O), gypsum (CaSO 4 · 2H 2 O) , CaCO 3 , and the like. The content of these minerals in the cement is not particularly limited, but typically 30 to 70 parts by mass of Alite (3CaO · SiO 2 ), assuming that the total amount of substances present in the cement is 100 parts by mass, Belite (2CaO · SiO 2) 20 to 60 parts by mass, 3CaO · Al 2 O 3 3 to 20 parts by mass, 4CaO · Al 2 O 3 · Fe 2 O 3 is 3 to 20 parts by weight, gypsum hemihydrate (CaSO 4 · 1 / 2H 2 O) is 1.4 to 2.7 parts by mass, dihydrate gypsum (CaSO 4 · 2H 2 O) is 2.0 to 5.4 parts by mass, and CaCO 3 is 0 to 7 parts by mass. There, more typically Alite (3CaO · SiO 2) is 40-65 parts by weight, Belite (2CaO · SiO 2) 10 to 30 parts by weight, 3CaO · Al 2 O 3 5 to 10 parts by mass, 4CaO · al 2 O 3 · Fe 2 O 3 5 to 15 parts by weight, hemihydrate Plaster (CaSO 4 · 1 / 2H 2 O) is from 1.4 to 2.4 parts by weight, gypsum (CaSO 4 · 2H 2 O) is from 2.0 to 4.7 parts by weight, CaCO 3 is 0-6 Part by mass.
 一般に、セメント中には、3CaO・Al23等の急激な水和反応による急結を防ぎ、安定した凝結時間を確保する為に、セメント製造時の粉砕工程で二水石膏が適量添加される。一方で、半水石膏はセメントの偽凝結を促進させる事から積極的に添加されることはなかった。本発明においては、急硬性セメント中のセメント中に半水石膏及び二水石膏を所定量含有することによって、凝結硬化時間を遅延させることを特徴の一つとしている。 Generally, an appropriate amount of dihydric gypsum is added to the cement during the pulverization process during cement production in order to prevent rapid setting due to a rapid hydration reaction such as 3CaO · Al 2 O 3 and to secure a stable setting time. The On the other hand, hemihydrate gypsum was not actively added because it promotes false setting of cement. One feature of the present invention is that the setting and hardening time is delayed by containing a predetermined amount of hemihydrate gypsum and dihydrate gypsum in the cement in the rapid-hardening cement.
 セメント中に半水石膏及び二水石膏を所定量含有させることで凝結硬化時間が遅延する理由については必ずしも明らかではなく、理論によって本発明が限定されることを意図するものではないが、乾燥によりCaSO4・2H2OからCaSO4・1/2H2Oへの脱水が進行し、その結果、急硬セメントの凝結硬化時間が長く確保されるものと考えられる。 The reason why the setting and hardening time is delayed by containing a predetermined amount of hemihydrate gypsum and dihydrate gypsum in the cement is not necessarily clear, and it is not intended that the present invention be limited by theory. It is considered that dehydration of CaSO 4 · 2H 2 O to CaSO 4 · 1 / 2H 2 O proceeds, and as a result, a long setting time of the hardened cement is secured.
 二水石膏は、過小では異常凝結、過多では膨張などの不具合を生じる為、上述した範囲でセメント中に含有するように添加することが望ましい。半水石膏は過小では凝結硬化時間を遅延させる効果が十分に得られず、過多では偽凝結が促進される傾向となるので、上述した範囲でセメント中に含有するように添加することが望ましい。 Since dihydric gypsum causes problems such as abnormal condensation when it is too small, and expansion when it is excessive, it is desirable to add it in the cement within the above-mentioned range. If hemihydrate gypsum is too small, the effect of delaying the setting and hardening time cannot be sufficiently obtained, and if too much, false setting tends to be promoted. Therefore, it is desirable to add it so as to be contained in the cement within the above-mentioned range.
 二水石膏に対する半水石膏の質量比が大きくなり過ぎると、偽凝結が促進される傾向となる。一方で、当該比が小さくなり過ぎると凝結硬化時間が短縮される傾向があるので、半水石膏/二水石膏=0.2~1.0であるのが好ましく、半水石膏/二水石膏=0.3~0.95であるのがより好ましく、半水石膏/二水石膏=0.4~0.6であるのが更により好ましい。 If the mass ratio of hemihydrate gypsum to dihydrate gypsum becomes too large, false condensation tends to be promoted. On the other hand, when the ratio becomes too small, the setting and hardening time tends to be shortened. Therefore, it is preferable that hemihydrate gypsum / dihydrate gypsum = 0.2 to 1.0, and hemihydrate gypsum / dihydrate gypsum. = 0.3 to 0.95 is more preferable, and hemihydrate gypsum / dihydrate gypsum = 0.4 to 0.6 is even more preferable.
 セメント中の半水石膏、二水石膏を所定量確保する方法としては、半水石膏、二水石膏をセメント製造におけるセメントクリンカー、石膏等の粉砕混合分級工程で、所定量添加する方法、二水石膏を粉砕混合分級工程で添加し、粉砕温度を上昇させ、半水石膏を生成させる方法、粉砕混合分級工程の後工程で乾燥し、半水石膏を得る方法がある。一般に乾燥は、乾燥させる物体の表面に充分な自由水が存在する段階では、物体表面が等しくなり、その乾燥速度は物体の含水率に依らず一定である定率乾燥速度域と、さらに乾燥を進めると、物体内部からの自由水の補給が蒸発速度に追いつかなくなる減率乾燥速度域とからなるが、定率乾燥速度域では乾燥後の含水率が減少している途中である為、減率乾燥速度域迄乾燥させる事が好ましい。減率乾燥速度域迄乾燥させる方法としては、セメントを送風乾燥機で乾燥する方法、セメント製造時の粉砕工程で二水石膏添加時の粉砕温度を上昇させて乾燥する方法等がある。 As a method of securing a predetermined amount of hemihydrate gypsum and dihydrate gypsum in cement, a method of adding a predetermined amount of hemihydrate gypsum and dihydrate gypsum in a cement clinker, gypsum, etc. in a cement manufacturing process, There are a method in which gypsum is added in the pulverizing and mixing step to raise the pulverization temperature to produce hemihydrate gypsum, and a method in which the gypsum is dried in the subsequent step of the pulverizing and mixing step to obtain hemihydrate gypsum. In general, in the drying process, when there is sufficient free water on the surface of the object to be dried, the object surface becomes equal, and the drying rate is constant regardless of the moisture content of the object, and the drying is further promoted. And a reduced rate drying rate area where free water replenishment from the inside of the object cannot keep up with the evaporation rate, but in the constant rate drying rate range, the moisture content after drying is in the process of decreasing, so the reduced rate drying rate It is preferable to dry to the area. As a method of drying to the reduced rate drying speed range, there are a method of drying the cement with an air dryer, a method of increasing the pulverization temperature at the time of adding dihydrate gypsum in the pulverization process at the time of cement production, and the like.
 所定量添加する方法としては、予め得られた半水石膏、二水石膏をセメントクリンカー等と共に、セメント粉砕ミル等に定量供給する方法が挙げられる。この場合は、製造される半水石膏、二水石膏量を確保する為、セメント粉砕ミルの温度を例えば、120℃以下に制御する等の方法が必要である。二水石膏を粉砕混合分級工程で添加し、粉砕温度を上昇させ、半水石膏を生成させる方法としては、セメント粉砕ミルの温度を例えば、110℃を越えて運転するが、半水石膏と二水石膏の比率を制御する為、120℃を超えない温度制御を水スプレイ等により行う事が有効である。粉砕混合分級工程の後工程で乾燥し、半水石膏を得る方法としては、セメントを100~80℃、更に好ましくは、95~85℃で乾燥する方法が有効である。乾燥方法は、セメントを送風乾燥機で乾燥する方法等がある。 Examples of the method of adding a predetermined amount include a method in which a preliminarily obtained hemihydrate gypsum and dihydrate gypsum are quantitatively supplied to a cement grinding mill or the like together with a cement clinker or the like. In this case, in order to secure the amount of hemihydrate gypsum and dihydrate gypsum to be produced, a method of controlling the temperature of the cement grinding mill to, for example, 120 ° C. or less is necessary. As a method of adding dihydrate gypsum in the pulverization and mixing and classifying step to raise the pulverization temperature and generate semi-hydrate gypsum, the temperature of the cement pulverization mill is operated at, for example, over 110 ° C. In order to control the ratio of water gypsum, it is effective to perform temperature control not exceeding 120 ° C. by water spray or the like. As a method of drying in the subsequent step of the pulverization and mixing step to obtain hemihydrate gypsum, a method of drying cement at 100 to 80 ° C., more preferably 95 to 85 ° C. is effective. Examples of the drying method include a method of drying cement with an air dryer.
 セメント中の石膏を示す指標としては、SO3が用いられ、SO3は、セメントクリンカー製造時の循環物質としてNa2SO4等の形態でクリンカー中に約0.1~0.2質量%程度、少量存在するが、これに加えて、二水石膏と半水石膏から構成される。セメント中のSO3は、JIS R5210ポルトランドセメントではSO3≦3.5質量%、JIS R5211高炉セメントではSO3≦4.0質量%、JIS R5212シリカセメントではSO3≦3.0質量%、JIS R5213フライアッシュセメントではSO3≦3.0質量%、JIS R5214エコセメントではSO3≦4.5質量%と規定されていて、セメント中のSO3は、大半がクリンカー粉砕時に加えられた二水石膏、及び半水石膏によるものである。セメント中の半水石膏及び二水石膏はX線回折リートベルト法により定量測定される。 As an index indicating gypsum in cement, SO 3 is used, and SO 3 is about 0.1 to 0.2% by mass in the clinker in the form of Na 2 SO 4 or the like as a circulating material during the production of the cement clinker. In addition to this, it is composed of dihydrate gypsum and hemihydrate gypsum. SO 3 in the cement, JIS R5210 SO 3 ≦ 3.5% by weight in Portland cement, SO 3 ≦ 4.0% by weight in JIS R5211 Blast furnace cement, SO 3 ≦ 3.0% by weight in JIS R5212 silica cement, JIS In R5213 fly ash cement, SO 3 ≦ 3.0% by mass, and in JIS R5214 ecocement, SO 3 ≦ 4.5% by mass. Most of the SO 3 in the cement is dihydrate added during clinker grinding. It is based on gypsum and hemihydrate gypsum. Hemihydrate gypsum and dihydrate gypsum in cement are quantitatively measured by the X-ray diffraction Rietveld method.
<急硬材>
(1)カルシウムアルミネート
 カルシウムアルミネートは急硬材として一般的に使用されている成分であり、急硬性を発揮する上で不可欠である。通常はCaO原料、Al23原料、並びに随意的にSiO2原料等を電気炉又はキルンで1,200~1,700℃で合成し、急冷することにより得られる鉱物である。例示的な組成としては、CaOが35~50質量%、Al23が40~55質量%、SiO2が1~15質量%である。例示的な化学物質としては、3CaO・Al23、12CaO・7Al23、11CaO・7Al23・CaF2、CaO・Al23、2CaO・Al23・SiO2、CaO・Al23・2SiO2、3CaO・3Al23・CaF2、3CaO・2Na2O・5Al23等が挙げられ、12CaO・7Al23が好ましい。
<Rapid hardwood>
(1) Calcium aluminate Calcium aluminate is a component generally used as a rapid hardening material, and is indispensable for exhibiting rapid hardening. Usually, it is a mineral obtained by synthesizing a CaO raw material, an Al 2 O 3 raw material, and optionally a SiO 2 raw material, etc., at 1,200 to 1,700 ° C. in an electric furnace or kiln and quenching. As an exemplary composition, CaO is 35 to 50% by mass, Al 2 O 3 is 40 to 55% by mass, and SiO 2 is 1 to 15% by mass. Exemplary chemicals, 3CaO · Al 2 O 3, 12CaO · 7Al 2 O 3, 11CaO · 7Al 2 O 3 · CaF 2, CaO · Al 2 O 3, 2CaO · Al 2 O 3 · SiO 2, CaO · Al 2 O 3 · 2SiO 2 , 3CaO · 3Al 2 O 3 · CaF 2, 3CaO · 2Na 2 O · 5Al 2 O 3 and the like, preferably 12CaO · 7Al 2 O 3.
 カルシウムアルミネートの含有量は高すぎると硬化後の異常膨張がある一方で、低すぎると短時間強度が不足するので急硬性セメント中で2~30質量%とするのが好ましく、5~20質量%とするのがより好ましい。 If the calcium aluminate content is too high, abnormal expansion will occur after curing, while if it is too low, the strength will be insufficient for a short time. % Is more preferable.
 カルシウムアルミネートは結晶質及びガラス質の何れの形態も可能であるが、電気炉等で溶融物を急冷したガラス質が好ましく、ガラス質が60質量%以上であると短時間強度発現に優れる。 Calcium aluminate can be in either crystalline or glassy form, but is preferably glassy obtained by quenching the melt with an electric furnace or the like.
 カルシウムアルミネートの粉末度はブレーン値で3,000~9,000cm2/gであるのが好ましい。 The fineness of calcium aluminate is preferably 3,000 to 9,000 cm 2 / g in terms of Blaine value.
(2)無水石膏
 無水石膏も急硬材として重要な成分であり、カルシウムアルミネートの水和と共に、急硬性水和物Ettringiteを形成する作用をすることから本発明に係る急硬性セメントには不可欠である。無水石膏の含有量は高すぎると硬化後の異常膨張を起こす一方で、低すぎると急硬性能が不足するので、急硬性セメント中で2~30質量%とするのが好ましく、5~20質量%とするのがより好ましい。
(2) Anhydrous gypsum Anhydrous gypsum is also an important component as a rapid hardening material and, together with the hydration of calcium aluminate, acts to form the rapid hardening hydrate Ettringite, which is essential for the rapid hardening cement according to the present invention. It is. If the content of anhydrous gypsum is too high, abnormal expansion will occur after curing, while if it is too low, the rapid hardening performance will be insufficient. Therefore, the content is preferably 2 to 30% by weight in the rapid hardening cement. % Is more preferable.
 無水石膏の粉末度はブレーン値で3,000~9,000cm2/gが好ましい。 The fineness of anhydrous gypsum is preferably 3,000 to 9,000 cm 2 / g in terms of Blaine value.
 カルシウムアルミネート及び無水石膏は、セメント100質量部に対して、合計で5~40質量部、更に好ましくは合計で5~30質量部添加する。カルシウムアルミネート及び無水石膏の合計が5質量部未満ではモルタル・コンクリートでの3時間強度が20MPa以上を示す急硬性能を示すことは困難であり、40質量部を超えて添加量を増しても、3時間強度である急硬性能は増加せず、又硬化後の異常膨張を起しやすい。 Calcium aluminate and anhydrous gypsum are added in a total amount of 5 to 40 parts by weight, more preferably 5 to 30 parts by weight, based on 100 parts by weight of cement. If the total of calcium aluminate and anhydrous gypsum is less than 5 parts by mass, it is difficult to show rapid hardening performance in which the strength for 3 hours in mortar and concrete is 20 MPa or more, and even if the amount added exceeds 40 parts by mass The rapid hardening performance, which is 3 hours strength, does not increase and tends to cause abnormal expansion after curing.
<凝結調整剤>
 本発明においては、炭酸塩及びオキシカルボン酸類等の凝結調整剤を加える事が不可欠である。炭酸塩としては、炭酸カリウム、炭酸ナトリウム、炭酸リチウム、炭酸水素ナトリム、炭酸水素カリウム等が挙げられる。オキシカルボン酸類としては、クエン酸、酒石酸、グルコン酸、リンゴ酸、酢酸、アジピン酸、コハク酸等のオキシカルボン酸及びこれらの塩が挙げられる。オキシカルボン酸塩としては、上記酸のナトリウム、カリウム、カルシウム、マグネシウム、アンモニウム、アルミニウム塩等が挙げられ、例えば、クエン酸ナトリウム、グルコン酸ナトリウム等が挙げられる。凝結調整剤は単独で使用することができ、二種以上を組み合わせて使用することもできる。
<Setting agent>
In the present invention, it is essential to add a coagulation adjusting agent such as carbonate and oxycarboxylic acid. Examples of the carbonate include potassium carbonate, sodium carbonate, lithium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and the like. Examples of oxycarboxylic acids include oxycarboxylic acids such as citric acid, tartaric acid, gluconic acid, malic acid, acetic acid, adipic acid, and succinic acid, and salts thereof. Examples of the oxycarboxylate include sodium, potassium, calcium, magnesium, ammonium, and aluminum salts of the above acids, and examples include sodium citrate and sodium gluconate. The setting modifier can be used alone or in combination of two or more.
 凝結調整剤の添加量は、セメント及び急硬材(カルシウムアルミネート+無水石膏)の合計質量に対して、好ましくは0.01~5質量%、更に好ましくは、0.05~2質量%添加する。凝結調整剤は、0.01質量%未満では十分なゲル化時間を確保出来ず、5質量%を超えて添加量を増しても、ゲル化時間が短縮される場合があり、十分なゲル化時間、例えば60分以上のゲル化時間を安定して確保することは困難である。 The amount of setting modifier added is preferably 0.01 to 5% by mass, more preferably 0.05 to 2% by mass, based on the total mass of cement and rapid hardening material (calcium aluminate + anhydrous gypsum). To do. If the setting modifier is less than 0.01% by mass, sufficient gelation time cannot be secured. Even if the addition amount exceeds 5% by mass, the gelation time may be shortened. It is difficult to stably ensure a time, for example, a gelation time of 60 minutes or more.
<その他のセメント混和剤>
 本発明に係る急硬性セメントにおいては、慣用されている各種のセメント混和剤を適宜添加することができる。例えば、減水剤、骨材等を添加することができる。また、緻密性や膨張性を付与させる為にシリカヒューム等のポゾラン物質、3CaO・3Al23・CaSO4等の物質を適量添加する事も有効である。
<Other cement admixtures>
In the quick-hardening cement according to the present invention, various conventional cement admixtures can be appropriately added. For example, a water reducing agent, aggregate, etc. can be added. It is also effective to add an appropriate amount of a substance such as a pozzolanic material such as silica fume, 3CaO.3Al 2 O 3 .CaSO 4 or the like in order to impart denseness and expandability.
<本発明に係る急硬性セメントの特性>
(1.乾燥減量)
 本発明に係る急硬性セメントの一実施形態においては、使用する原料セメントは90℃で20時間乾燥後の減量分が0.25質量%以下であり、好ましくは0.2質量%以下であり、より好ましくは0.1質量%以下である。このように、90℃における乾燥減量が少ないことにより、5℃でのゲル化時間を長く、好ましくは60分以上とすることができ、5℃での硬化時間を長く、好ましくは60分以上とすることができる。
<Characteristics of rapid hardening cement according to the present invention>
(1. Loss on drying)
In one embodiment of the quick-hardening cement according to the present invention, the raw material cement used has a weight loss after drying at 90 ° C. for 20 hours of 0.25% by mass or less, preferably 0.2% by mass or less, More preferably, it is 0.1 mass% or less. Thus, by reducing the loss on drying at 90 ° C., the gelation time at 5 ° C. can be lengthened, preferably 60 minutes or longer, and the curing time at 5 ° C. can be lengthened, preferably 60 minutes or longer. can do.
(2.ゲル化時間及び硬化時間)
 本発明では急硬性セメントの凝結硬化特性を評価するための指標の一つとして、ゲル化時間を定義する。ゲル化時間は、特定の周囲温度において、急硬性セメントペースト200g(急硬性セメント156g+水44g)について注水混練後の時間と温度上昇の関係を測定し、セメントペーストの温度が硬化に伴う発熱により2℃上昇するまでに要する時間である。また、本発明では急硬性セメントの凝結硬化時間を評価するための指標の一つとして、硬化時間を定義する。硬化時間は、急硬性セメントペースト200gについて注水混練後の時間と温度上昇の関係を測定し、混練セメントペーストの温度が硬化に伴う発熱により5℃上昇するまでに要する時間である。
(2. Gelation time and curing time)
In the present invention, gelation time is defined as one of the indexes for evaluating the setting and hardening characteristics of rapid-hardening cement. The gelation time is determined by measuring the relationship between the time after pouring water mixing and the temperature rise for 200 g of rapid hardening cement paste (fast hardening cement 156 g + 44 g of water) at a specific ambient temperature. This is the time required for the temperature to rise. In the present invention, the setting time is defined as one of the indexes for evaluating the setting and setting time of the rapid hardening cement. The setting time is a time required for the temperature of the kneaded cement paste to rise by 5 ° C. due to the heat generated by hardening, after measuring the relationship between the time after water pouring and the temperature rise for 200 g of the rapid hardening cement paste.
 急硬セメントペーストは、ゲル化及び硬化により温度上昇を伴い流動性を失う。流動性を失う指標としては、ロート内での滞留時間が長くなるという指標を利用するのが有効であり、図1-1、図1-2に、理解の容易性の観点から、凝結硬化時間の不十分な急硬性セメントと凝結硬化時間の十分に長い急硬性セメントについての、ゲル化時間及び硬化時間を、温度上昇、流動性低下指標と共に、模式的に示す。ゲル化を経て硬化に至ると共に、Jロート無収縮モルタル品質管理試験方法(日本道路公団規格JHS 312)、KC-57 Jロート(道路公団型)により測定した滴下時間が急激に長くなり、流動性を失う現象が理解出来る。 Rapid hardening cement paste loses its fluidity with increasing temperature due to gelation and hardening. As an index for losing fluidity, it is effective to use an index that the residence time in the funnel becomes long. FIGS. 1-1 and 1-2 show the setting and hardening time from the viewpoint of easy understanding. The gelation time and the setting time for the insufficiently setting rapid setting cement and the setting cement having a sufficiently long setting time are shown schematically together with an increase in temperature and a decrease in fluidity. It is hardened through gelation, and dripping time measured by J-Rottle non-shrink mortar quality control test method (Japan Highway Public Corporation Standard JHS 312), KC-57 J-Rote (Highway Public Corporation type) is drastically increased, and its fluidity I can understand the phenomenon of losing.
 ゲル化に伴い、急硬性セメントペーストの粘度の上昇が起こり、硬化に至っては、急硬性ペーストが硬化し、強度が急激に上昇し、3時間程度経過後には、モルタル・コンクリート硬化体の強度が20Mpaを超え、土木用構造物等の実用に供される。具体的には、急硬性セメントペーストの混練直後は、粘度が800cps程度であるが、ゲル化に伴い、急硬性セメントペーストの粘度は10,000cpsを超え、ミキサによる混練、急硬性ペーストの注入、打設、締め固め等の作業の確保が困難となる。混練後の急硬性セメントペーストの粘度の測定方法は、滴下時間の測定方法として、Jロート無収縮モルタル品質管理試験方法(日本道路公団規格JHS 312)、ロートはKC-57 Jロート(道路公団型)、JIS R5210に示すモルタルフロー、JIS Z8803「液体の粘度-測定方法」による回転粘度測定方法等がある。一般に、急硬性セメントペーストは、硬化時間経過後は硬化して、プロクター貫入抵抗試験方法(JIS A 6204付属書I)により約1[N/mm2]を記録する。 Along with gelation, the viscosity of the rapid hardening cement paste increases, and when it hardens, the rapid hardening paste hardens, and the strength rapidly increases. After about 3 hours, the strength of the hardened mortar / concrete is increased. It exceeds 20 Mpa and is used for civil engineering structures. Specifically, the viscosity is about 800 cps immediately after kneading of the rapid hardening cement paste, but with the gelation, the viscosity of the rapid hardening cement paste exceeds 10,000 cps, kneading with a mixer, injection of the rapid hardening paste, It is difficult to secure operations such as placing and compacting. The viscosity of the hardened cement paste after kneading is measured by the J-rote non-shrink mortar quality control test method (Japan Highway Public Standard JHS 312), and the funnel is KC-57 J ), Mortar flow shown in JIS R5210, rotational viscosity measurement method according to JIS Z8803 “liquid viscosity-measurement method”, and the like. Generally, a rapid hardening cement paste hardens after the curing time has elapsed, and records about 1 [N / mm 2 ] according to the Procter penetration resistance test method (JIS A 6204 Annex I).
 ゲル化時間及び硬化時間があまりに短い場合、急硬性セメントペーストに骨材(砂、砂利等)を加えたセメントコンクリート等による構造物の打設、或いは砂等を加えたセメントモルタル等による補修工事を一般的に行う作業時間を確保することができなくなってしまう。寒冷期における工事現場でのコンクリートポンプ等を用いたモルタル、コンクリート等による大量打設を実用的に行うためには5℃でのゲル化時間及び硬化時間が十分に長いことが望まれる。 If the gelation time and setting time are too short, construct a structure with cement concrete, etc. with the addition of aggregate (sand, gravel, etc.) to rapid hardening cement paste, or repair work with cement mortar with addition of sand, etc. It becomes impossible to ensure the work time generally performed. It is desirable that the gelation time and the curing time at 5 ° C. be sufficiently long in order to practically perform mass placement with mortar, concrete, etc. using a concrete pump or the like at a construction site in the cold season.
 本発明に係る急硬性セメントペースト、セメントモルタル又はセメントコンクリートの一実施形態においては、5℃でのゲル化時間が60分以上であり、好ましくは70分以上であり、例えば60~80分とすることができる。 In one embodiment of the rapid hardening cement paste, cement mortar or cement concrete according to the present invention, the gelation time at 5 ° C. is 60 minutes or longer, preferably 70 minutes or longer, for example 60 to 80 minutes. be able to.
 本発明に係る急硬性セメントペースト、セメントモルタル又はセメントコンクリートの一実施形態においては、5℃での硬化時間が60分以上であり、好ましくは70分以上であり、例えば60~80分とすることができる。 In one embodiment of the rapid hardening cement paste, cement mortar or cement concrete according to the present invention, the curing time at 5 ° C. is 60 minutes or longer, preferably 70 minutes or longer, for example 60 to 80 minutes. Can do.
<製造方法>
 本発明に係る急硬性セメントは、上述したセメント、急硬材、凝結調整剤等を混合することにより製造可能である。そして、当該急硬性セメントに水を加え、一般のミキサー、好ましくは強制練りミキサーにより原材料を混練りすれば急硬性セメントペーストが製造できる。水の添加量は、多すぎると材料分離が発生する一方で、少なすぎると流動性が得られないので、急硬性セメント100質量部に対して、10~50質量部とするのが好ましく、15~45質量部とするのがより好ましく、典型的には20~40質量部とすることができる。
<Manufacturing method>
The quick-hardening cement according to the present invention can be manufactured by mixing the above-mentioned cement, quick-hardening material, setting modifier, and the like. Then, by adding water to the rapid-hardening cement and kneading the raw materials with a general mixer, preferably a forced kneading mixer, a quick-hardening cement paste can be produced. When the amount of water added is too large, material separation occurs, but when it is too small, fluidity cannot be obtained. Therefore, the amount is preferably 10 to 50 parts by mass with respect to 100 parts by mass of the rapid-hardening cement. It is more preferable that the amount be ˜45 parts by mass, and typically 20 to 40 parts by mass.
 本発明に係る急硬性セメントペーストは、凝結硬化時間が長いため、作業性及び施工性が高い。そのため、例えばグレーダー、ブルドーザー及びフィニッシャ等で敷き均らすことができ、更に、ハンマー、タイヤローラ及び振動ローラ等で締め固め転圧することにより早期に高い強度を得ることができる。本発明に係る急硬性セメントペーストは特に低温環境下での作業性及び施工性に優れており、例えば1~10℃での温度環境下において打設するのに好適に使用できる。 The rapid-hardening cement paste according to the present invention has high workability and workability because of a long setting and hardening time. For this reason, for example, a grader, a bulldozer, a finisher or the like can be used to spread and further high strength can be obtained at an early stage by compacting and rolling with a hammer, a tire roller, a vibration roller, or the like. The quick-hardening cement paste according to the present invention is particularly excellent in workability and workability in a low temperature environment, and can be suitably used for placing in a temperature environment of 1 to 10 ° C., for example.
 本発明に係る急硬性セメントペーストの硬化物は、モルタルやコンクリートとして、例えば、道路、鉄道、及び導水路等のトンネルにおいて、露出した地山面への覆工時やトンネルの補修等といった覆工時に使用することが可能である。 The hardened cement paste according to the present invention is a hardened mortar or concrete, for example, in tunnels such as roads, railways, water conduits, etc. It can be used sometimes.
 以下、本発明の実施例について説明するが、これらは例示目的であって本発明が限定されることを意図するものではない。 Examples of the present invention will be described below, but these are for illustrative purposes and are not intended to limit the present invention.
 表1に記載の各組成をもつ粉末状の普通ポルトランドセメント(No.1~4)を調製した。セメント中の物質量はリートベルト法による化学成分分析により得た値である。具体的には、「SIROQUANT Version2.5」(Sietronics社製)を用いて粉末X線回折により回折強度から各化学成分の物質量を定量した。また、表2に、JIS R5202による化学分析の結果も合わせて掲載した。 A powdery ordinary Portland cement (No. 1 to 4) having each composition shown in Table 1 was prepared. The amount of substance in the cement is a value obtained by chemical composition analysis by Rietveld method. Specifically, the amount of each chemical component was determined from the diffraction intensity by powder X-ray diffraction using “SIROQUANT® Version 2.5” (manufactured by Sietronics). Table 2 also shows the results of chemical analysis according to JIS R5202.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
<各種温度における乾燥減量>
 上記各セメントについて、乾燥減量を測定した。地盤工学会基準(改正案)「JGS0121:0000土の含水比試験方法」は110℃乾燥減量の測定方法であり、恒温乾燥炉は、電動ファンによって炉内空気を強制的に循環させる循環送風式のものが望ましいと記述されている為、当該乾燥炉により、50℃、90℃、105℃、140℃の乾燥減量を測定した。一定質量になるまでの時間は、一般には18~24時間程度であると記載されている為、20時間で乾燥を行った。結果を表3に示す。表3より、特に50℃及び90℃における乾燥減量が、比較例に比べて発明例の方が少なく、90℃乾燥減量が0.25質量%以下となることが分かる。
<Loss on drying at various temperatures>
About each said cement, loss on drying was measured. Geotechnical Society standards (draft draft) “JGS0121: 0000 Soil moisture content test method” is a method for measuring the loss on drying at 110 ° C., and the constant temperature drying furnace is a circulating fan type that forcibly circulates the air in the furnace with an electric fan. Therefore, the loss on drying at 50 ° C., 90 ° C., 105 ° C., and 140 ° C. was measured by the drying furnace. Since the time until reaching a constant mass is generally described to be about 18 to 24 hours, drying was performed in 20 hours. The results are shown in Table 3. From Table 3, it can be seen that the loss on drying especially at 50 ° C. and 90 ° C. is smaller in the inventive examples than in the comparative examples, and the loss on drying at 90 ° C. is 0.25% by mass or less.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
<密度及びブレーン比表面積>
 JIS R5201(セメントの物理試験方法)に準拠して、上記各セメントの密度及びブレーン比表面積を測定した。結果を表4に示す。
<Density and Blaine specific surface area>
In accordance with JIS R5201 (cement physical test method), the density and brane specific surface area of each cement were measured. The results are shown in Table 4.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
<溶出試験によるイオン分析>
 また、上記セメントに対して以下の溶出試験を行い、5℃でのイオン分析を行った。セメント25gと純粋25mLをビーカーに入れ、所定時間スターラーで攪拌し、吸引濾過にて固相部分と液相部分に分けた。液相部分に含まれる各種イオンをフレーム原子吸光分析(Ca、Na、K、JIS K0102「工場排水試験方法、)及びイオンクロマト分析(SO4 2-、JIS K0102「工場排水試験方法」)により定量した。結果を表5及び図2に示す。
<Ion analysis by dissolution test>
Further, the following elution test was performed on the cement, and ion analysis was performed at 5 ° C. 25 g of cement and 25 mL of pure were put into a beaker, stirred with a stirrer for a predetermined time, and separated into a solid phase portion and a liquid phase portion by suction filtration. Various ions contained in the liquid phase are quantified by flame atomic absorption spectrometry (Ca, Na, K, JIS K0102 “Factory wastewater test method”) and ion chromatographic analysis (SO 4 2- , JIS K0102 “Factory wastewater test method”). did. The results are shown in Table 5 and FIG.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
 上記各セメントに、下記の原材料(A)~(E)を表6に記載の各質量部で混合して急硬性セメントを製造し、次いで、表6に記載の質量部の水を添加して混練し、発明例及び比較例の急硬性セメントのペーストを製造した。
(A)カルシウムアルミネート(12CaO・7Al23):2000kVA電気炉により1600℃の溶融物を急冷して、吹き飛ばす工程によりガラス質化した12CaO・7Al23を、粉末度4,500[cm2/g](ブレーン値)に粉砕した電気化学工業(株)青海工場製造品、ガラス質:95質量%、ガラス質の測定方法は、X線回折リートベルト法、「SIROQUANT Version2.5」(Sietronics社製)を用いて粉末X線回折により回折強度から定量した。
(B)無水石膏:粉末度4,500cm2/g(ブレーン値)に粉砕した電気化学工業(株)青海工場製造品
(C)減水剤(セルフロー110P):「セルフロー110P」(第一工業製薬)
(D)炭酸カリウム:旭硝子(株)製造品
(E)精製クエン酸:扶桑化学工業(株)製造品
(F)水:工業用水
The following raw materials (A) to (E) are mixed with each of the above-mentioned cements in each part by mass shown in Table 6 to produce a quick-hardening cement, and then, the parts by mass of water shown in Table 6 are added. Kneading was carried out to produce pastes of the quick-hardening cements of the inventive examples and comparative examples.
(A) Calcium aluminate (12CaO · 7Al 2 O 3) : 2000kVA by quenching the melt of 1600 ° C. by an electric furnace, a 12CaO · 7Al 2 O 3 was vitrified by step blow off, degree of fineness 4,500 [ cm 2 / g] (brane value), manufactured by Denki Kagaku Kogyo Co., Ltd., Aomi factory, glass quality: 95% by mass, glass quality is measured by X-ray diffraction Rietveld method, “SIROQUANT Version2.5” (Sietronics Co., Ltd.) was used to quantify the diffraction intensity by powder X-ray diffraction.
(B) Anhydrous gypsum: Electrochemical Industry Co., Ltd. Aomi factory manufactured to a fineness of 4,500 cm 2 / g (Brain value) (C) Water reducing agent (Cell Flow 110P): “Cell Flow 110P” (Daiichi Kogyo Seiyaku) )
(D) Potassium carbonate: Asahi Glass Co., Ltd. manufactured product (E) Purified citric acid: Fuso Chemical Industry Co., Ltd. manufactured product (F) Water: Industrial water
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
 得られた急硬性セメントペーストについて、硬化特性(表7)を測定した。実験条件について以下に示す。 The hardening characteristics (Table 7) were measured for the obtained quick-hardening cement paste. The experimental conditions are shown below.
<硬化特性>
 急硬性セメントペースト200gについて注水混練後の時間と温度上昇の関係を測定した。混練セメントペーストの温度が2℃上昇した時間をゲル化時間、5℃上昇した時間を硬化時間と定義した。ゲル化時間経過後は、ペーストの粘性が上昇、ペーストはこわばり状態を呈し、硬化時間経過後は、ペーストは硬化し、プロクター貫入抵抗試験方法(JIS A 6204付属書I)により約1N/mm2を記録した。
 また、急硬セメントペーストのゲル化時間及び硬化時間が共に60分以上確保されている場合は「正常」とし、何れか一方でも60分未満である場合は、「異常」と判定した。
<Curing characteristics>
With respect to 200 g of the quick-hardening cement paste, the relationship between the time after water pouring and the temperature rise was measured. The time when the temperature of the kneaded cement paste was raised by 2 ° C. was defined as the gel time, and the time when the temperature was raised by 5 ° C. was defined as the setting time. After the gelation time has elapsed, the viscosity of the paste increases, and the paste exhibits a stiff state. After the curing time has elapsed, the paste hardens and is approximately 1 N / mm 2 according to the Procter penetration resistance test method (JIS A 6204 Annex I). Was recorded.
In addition, when both the gelation time and the setting time of the rapid hardening cement paste were secured for 60 minutes or more, it was determined as “normal”, and when either one was less than 60 minutes, it was determined as “abnormal”.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
 表7より、本発明に係る急硬性セメント(No.1、2)では、温度上昇が抑制され、養生温度が30℃、20℃、5℃と低下するに従い、ゲル化時間が50分台、60分台、70分台と増加し、50分以上確保されている。これに対し、比較例に係る急硬性セメント(No.3、No.4)では、ゲル化時間は、養生温度が30℃、20℃、5℃と低下するに従い、40分台から20分台まで減少し、特に5℃では30分未満と著しく短い。また、硬化時間についても発明例に比べて著しく短い。 From Table 7, in the rapid-hardening cement (No. 1, 2) according to the present invention, as the temperature rise is suppressed and the curing temperature decreases to 30 ° C., 20 ° C., 5 ° C., the gelation time is in the range of 50 minutes, It increased to 60 minutes and 70 minutes, and more than 50 minutes were secured. On the other hand, in the quick-hardening cement (No. 3, No. 4) according to the comparative example, the gelation time is in the range from 40 minutes to 20 minutes as the curing temperature decreases to 30 ° C., 20 ° C., and 5 ° C. Especially at 5 ° C., it is remarkably short as less than 30 minutes. Also, the curing time is significantly shorter than that of the inventive examples.
<考察>
 表1に示されるセメント中のリートベルト法による各化学成分の物質量は、何れの試験番号に係る急硬性セメントも、Alite(3CaO・SiO2)が60~50質量%、Belite(2CaO・SiO2)が20~10質量%、3CaO・Al23が10~5質量%、4CaO・Al23・Fe23が15~5質量%の範囲内で本発明と比較例で有意な差は無い。これに対し、初期の凝結硬化に影響を与える二水石膏と半水石膏を比較すると、発明例では、半水石膏が1.4~2.2質量%と多く、二水石膏が2.4~2.8質量%と少ないのに対し、比較例では、半水石膏が0.8~1.3質量%と少なく、二水石膏が3.3~3.7質量%と多い。
<Discussion>
The amount of each chemical component in the cement shown in Table 1 according to the Rietveld method is 60 to 50% by mass of Alite (3CaO · SiO 2 ) and Belite (2CaO · SiO 2 ) for any of the rapid hardening cements according to any test number. 2 ) is 20 to 10% by mass, 3CaO.Al 2 O 3 is 10 to 5% by mass, and 4CaO.Al 2 O 3 .Fe 2 O 3 is 15 to 5% by mass. There is no difference. On the other hand, when comparing dihydrate gypsum and hemihydrate gypsum that affect the initial setting and hardening, in the invention example, the amount of hemihydrate gypsum is as high as 1.4 to 2.2% by mass, and dihydrate gypsum is 2.4%. In contrast, the comparative example has a small amount of hemihydrate gypsum as 0.8 to 1.3% by mass and a dihydrate gypsum as large as 3.3 to 3.7% by mass.
 このことから、ゲル化時間、硬化時間、及び乾燥減量は、急硬性セメント中の半水石膏と二水石膏の配合条件が有意な影響を与えていることが分かり、本発明で規定する配合条件とすることが有利であることが理解できる。 From this, it can be seen that the gelation time, setting time, and loss on drying have a significant effect on the mixing conditions of hemihydrate gypsum and dihydrate gypsum in the rapid-hardening cement, and the mixing conditions specified in the present invention. It can be understood that it is advantageous.
 また、溶出試験によるイオン分析の結果を示す表5及び図2から、比較例では、溶出初期段階での1~5分でのCa及びSO4 2-の量が低く、Ca及びSO4 2-の溶解が抑制されている。一方で、本発明では、溶出初期段階での1~5分でのCa及びSO4 2-の量が高く、Ca及びSO4 2-の溶解が早い。Ca及びSO4 2-のの溶解は、半水石膏量と相関がある。即ち、本発明の急硬性セメントペーストでは、半水石膏量が1.4~2.2質量%と多い為、溶出初期段階での1~5分でのCa及びSO4 2-の量が高い。このことから、Ca及びSO4 2-の溶解が促進されて、普通セメントに含有される3CaO・Al23、4CaO・Al23・Fe23と二水石膏、半水石膏との水和が促進されて凝結が確保され、それにより、急硬性混和材の水和が抑制されて、凝結が確保されると考えられる。 Further, from Table 5 and FIG. 2 showing the results of the ion analysis by the dissolution test, in the comparative example, the amount of Ca and SO 4 2- in 1 to 5 minutes in the initial stage of dissolution is low, and Ca and SO 4 2- Dissolution is suppressed. On the other hand, in the present invention, high Ca and SO 4 amount of 2 at 1-5 minutes of elution early stages, Ca and SO 4 dissolved in 2-fast. The dissolution of Ca and SO 4 2- correlates with the amount of hemihydrate gypsum. That is, in the quick-hardening cement paste of the present invention, the amount of hemihydrate gypsum is as large as 1.4 to 2.2% by mass, so that the amount of Ca and SO 4 2- in 1 to 5 minutes in the initial elution stage is high. . Therefore, Ca and SO 4 2-dissolution is promoted, usually 3CaO · Al 2 O 3 the cement contained in, 4CaO · Al 2 O 3 · Fe 2 O 3 and gypsum, and hemihydrate gypsum It is considered that the hydration of the rapid hardening admixture is suppressed by accelerating the hydration of the mixture, thereby suppressing the hydration of the rapid-hardening admixture.

Claims (10)

  1.  (A)セメント、(B)カルシウムアルミネート及び無水石膏を含有する急硬材、(C)凝結調整剤を含有する急硬性セメントであって、(A)セメント100質量部中に半水石膏が1.4~2.7質量部、二水石膏が2.0~5.4質量部含まれる急硬性セメント。 (A) a cement, (B) a rapid hardening material containing calcium aluminate and anhydrous gypsum, and (C) a rapid hardening cement containing a setting modifier, wherein (A) hemihydrate gypsum is contained in 100 parts by mass of cement. A rapid-hardening cement containing 1.4 to 2.7 parts by mass and 2.0 to 5.4 parts by mass of dihydrate gypsum.
  2.  半水石膏と二水石膏の質量比が半水石膏/二水石膏=0.2~1.0である請求項1に記載の急硬性セメント。 The rapid-hardening cement according to claim 1, wherein the mass ratio of hemihydrate gypsum to dihydrate gypsum is hemihydrate gypsum / dihydrate gypsum = 0.2 to 1.0.
  3.  半水石膏と二水石膏の質量比が半水石膏/二水石膏=0.4~0.6である請求項1に記載の急硬性セメント。 The rapid-hardening cement according to claim 1, wherein the mass ratio of hemihydrate gypsum to dihydrate gypsum is hemihydrate gypsum / dihydrate gypsum = 0.4 to 0.6.
  4.  (A)セメントは90℃で20時間乾燥後の減量分が0.25質量%以下である請求項1~3の何れか一項に記載の急硬性セメント。 The rapid hardening cement according to any one of claims 1 to 3, wherein (A) the cement has a weight loss of 0.25% by mass or less after drying at 90 ° C for 20 hours.
  5.  急硬性セメント中の(A)セメントの含有量が70~95質量%であり、カルシウムアルミネート及び無水石膏は(A)セメント100質量部に対して合計で5~40質量部であり、(C)凝結調整剤は、(A)セメント、カルシウムアルミネート及び無水石膏の合計質量に対して0.01~5質量%である請求項1~4の何れか一項に記載の急硬性セメント。 The content of (A) cement in the quick-hardening cement is 70 to 95% by mass, and calcium aluminate and anhydrous gypsum are 5 to 40 parts by mass in total with respect to 100 parts by mass of (A) (C The rapid setting cement according to any one of claims 1 to 4, wherein the setting modifier is 0.01 to 5% by mass relative to the total mass of (A) cement, calcium aluminate and anhydrous gypsum.
  6.  請求項1~5の何れか一項に記載の急硬性セメントを使用したセメントペースト、セメントモルタル又はセメントコンクリート。 Cement paste, cement mortar, or cement concrete using the rapid hardening cement according to any one of claims 1 to 5.
  7.  5℃でのゲル化時間が60分以上である請求項6に記載のセメントペースト、セメントモルタル又はセメントコンクリート。 The cement paste, cement mortar or cement concrete according to claim 6, wherein the gelation time at 5 ° C is 60 minutes or more.
  8.  5℃での硬化時間が60分以上である請求項6又は7に記載のセメントペースト、セメントモルタル又はセメントコンクリート。 The cement paste, cement mortar or cement concrete according to claim 6 or 7, wherein the curing time at 5 ° C is 60 minutes or more.
  9.  請求項6~8の何れか一項に記載のセメントペースト、セメントモルタル又はセメントコンクリートの硬化物。 A cured product of the cement paste, cement mortar or cement concrete according to any one of claims 6 to 8.
  10.  請求項6~8の何れか一項に記載のセメントペースト、セメントモルタル又はセメントコンクリートを1~10℃の温度環境で打設することを含むセメントペースト、セメントモルタル又はセメントコンクリートの使用方法。 A method of using a cement paste, cement mortar or cement concrete comprising placing the cement paste, cement mortar or cement concrete according to any one of claims 6 to 8 in a temperature environment of 1 to 10 ° C.
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JP2017154947A (en) * 2016-03-03 2017-09-07 太平洋セメント株式会社 Selectin method for gypsum and method for producing portland cement
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JP7453047B2 (en) 2020-04-14 2024-03-19 デンカ株式会社 Cement quick setting agent and cement composition

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