WO2017179122A1 - Cement additive and cement composition - Google Patents

Cement additive and cement composition Download PDF

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Publication number
WO2017179122A1
WO2017179122A1 PCT/JP2016/061809 JP2016061809W WO2017179122A1 WO 2017179122 A1 WO2017179122 A1 WO 2017179122A1 JP 2016061809 W JP2016061809 W JP 2016061809W WO 2017179122 A1 WO2017179122 A1 WO 2017179122A1
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Prior art keywords
cement
additive
indicated
cement additive
calcium sulfite
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PCT/JP2016/061809
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French (fr)
Japanese (ja)
Inventor
将貴 宇城
盛岡　実
啓史 原
雅昭 渡辺
八嶋　裕之
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デンカ株式会社
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Priority to PCT/JP2016/061809 priority Critical patent/WO2017179122A1/en
Priority to JP2018511798A priority patent/JPWO2017179122A1/en
Publication of WO2017179122A1 publication Critical patent/WO2017179122A1/en

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
    • C04B22/08—Acids or salts thereof
    • C04B22/14—Acids or salts thereof containing sulfur in the anion, e.g. sulfides
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions 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

Definitions

  • the present invention mainly relates to a cement additive and a cement composition used in the civil engineering and construction industries.
  • Calcium sulfite is well known as a hexavalent chromium reducing agent (for example, Patent Documents 1 to 5).
  • calcium sulfite is widely used as a soil conditioner containing heavy metals used with gypsum and cement because it is obtained in large quantities as a by-product in the type of flue gas desulfurization equipment that uses quicklime as an SOx absorbent. ing.
  • calcium sulfite obtained as a by-product in the flue gas desulfurization apparatus has a pH in the acidic region of about 4-7.
  • sulfite paintings such as alkali metals or alkaline earth metals are also known as cement admixtures that reduce slump loss in cement and mortar materials (Patent Documents 6 to 10).
  • calcium sulfite used here is a high-purity industrial chemical, and is a neutral salt having a pH of about 8.0 or less.
  • Japanese Unexamined Patent Publication No. 11-302644 Japanese Unexamined Patent Publication No. 2007-246306 Japanese Unexamined Patent Publication No. 2008-174436 Japanese Unexamined Patent Publication No. 2010-201406 Japanese Unexamined Patent Publication No. 2012-24863 Japanese Unexamined Patent Publication No. 9-295843 Japanese Unexamined Patent Publication No. 10-265249 Japanese Unexamined Patent Publication No. 10-291844 Japanese Unexamined Patent Publication No. 11-79819 Japanese Unexamined Patent Publication No. 11-79822
  • the good fluidity retention effect and self-shrinkage reduction effect of cement concrete can be obtained, and in addition, the reducing action of hexavalent chromium having both immediate effect and sustainability can be achieved. It aims at providing the cement additive and cement composition which exhibit.
  • the present inventor has conducted earnest research to achieve the above object, and contains calcium sulfite, which is a by-product in producing a lime-sulfur mixture, and has a pH of 9.0 or more, preferably, It has been found that a cement additive having an oxidation-reduction potential (ORP) of 50 mV or less and a cement composition to which the cement additive is added achieve the above object.
  • ORP oxidation-reduction potential
  • the present invention is based on the above findings and is summarized as follows. That is, the present invention provides (1) a cement additive containing calcium sulfite, which is a by-product when producing a lime-sulfur mixture, and (2) a cement according to claim 1 having a pH of 9.0 or more.
  • Additive, (3) redox potential (ORP) is 50 mV or less (1) or (2) cement additive, (4) MgO content is 0.5% or more (1) to (3) (5) Cement and a cement composition containing any one of the cement additives (1) to (4), (6) 0.05 to 2 parts added to 100 parts of cement (5) the cement composition. (7) The cement composition according to (5) or (6), wherein the cement is Portland cement.
  • the cement concrete referred to in the present invention is a general term for cement paste, cement mortar, and concrete.
  • the calcium sulfite referred to in the present invention is a general term for calcium sulfite anhydrous and calcium sulfite hemihydrate.
  • the cement additive of the present invention contains calcium sulfite, which is a by-product when producing a lime sulfur mixture, and has a pH of 9.0 or more.
  • the lime-sulfur mixture has various composition ratios and characteristics depending on the use ratio of the raw lime, sulfur, and water, and the reaction conditions in the autoclave. That is, the ratio of quick lime and sulfur: water as raw materials is preferably 1.2 to 3 parts of sulfur and 2.5 to 5 parts of water with respect to 1 part of quick lime, particularly preferably 1.5 to 2 parts of sulfur and 3 to 4 parts of water are used.
  • the reaction is preferably carried out under a pressurized condition of 3.5 to 10 atmospheres, preferably 140 to 180 ° C.
  • the reaction is preferably carried out in an autoclave.
  • Calcium sulfite a by-product of producing lime-sulfur mixture, separates the reaction mixture of quick lime, sulfur, and water by solid-liquid separation with a filter press, etc., so that the mainstream multi-fluidized calcium is separated as a liquid It becomes a so-called lime sulfur mixture.
  • the remaining solid substance is dried at 50 to 120 ° C., more preferably 70 to 105 ° C. under reduced pressure or in the air.
  • calcium sulfite hemihydrate is confirmed.
  • the content of calcium sulfite hemihydrate in 100 parts by weight of this by-product is usually 75% to 95% or more.
  • This by-product calcium sulfite has various properties including pH depending on the use ratio of raw lime, sulfur and water, and reaction conditions in the autoclave.
  • the cement additive containing calcium sulfite which is a by-product when producing a lime sulfur mixture, has an alkaline region having a pH of 9.0 or more.
  • the pH of the cement additive is preferably 10.0 or more.
  • the pH is preferably larger, but is preferably 13.0 or less from the viewpoint of handling safety.
  • the pH is measured by adding 100 ml of pure water to 10 g of cement additive containing calcium sulfite, which is a byproduct of the lime sulfur mixture, and stirring the pH of the supernatant liquid using an ion electrode pH meter.
  • the oxidation-reduction potential (ORP) of the cement additive of this invention containing the by-product at the time of manufacturing a lime sulfur mixture is 50 mv or less.
  • the ORP of the reagent calcium sulfite is approximately 100 mV. If the ORP of the cement additive is not in the range of 50 mv or less, the effects of the present invention, that is, the fluidity retention effect, the hexavalent chromium reduction effect, and the self-shrinkage reduction effect may not be sufficiently obtained. .
  • ORP has preferable 35 mv or less.
  • ORP is preferably small, and the lower limit value of the ORP is not particularly limited as long as it does not impair the effects of the present invention.
  • ORP said by this invention means ORP of the supernatant liquid after adding 100 ml of pure waters to 10 g of cement additives, and stirring.
  • the cement additive of the present invention containing a lime-sulfur mixture by-product preferably contains Mg in a range of 0.5 to 2.0% in terms of MgO.
  • Mg content is less than 0.5% in terms of MgO, the effects of the present invention, that is, the fluidity retention effect, the hexavalent chromium reduction effect, and the self-shrinkage reduction effect are not sufficiently obtained.
  • the Mg content is preferably 0.7 or more, and more preferably 1.0 or more.
  • the Mg content is preferably larger, but is preferably 2.0 or less because it may be substituted for Ca in mentor hydrate to promote alteration.
  • the particle size of the byproduct of the lime-sulfur mixture contained in the cement additive of the present invention is not particularly limited, but the average particle size is preferably 5 to 30 ⁇ m, more preferably 10 to 20 ⁇ m. Also, 2,000 ⁇ 8,000cm 2 / g are preferred in Blaine specific surface area, more preferably 3500 ⁇ 5000cm 2 / g.
  • the specific surface area of the brane is less than 2000 cm 2 / g, the immediate effect may not be sufficiently obtained for the reduction effect of hexavalent chromium. Moreover, when it exceeds 8000 cm ⁇ 2 > / g, sustainability may not fully be acquired about the reduction effect of hexavalent chromium.
  • the average particle diameter here represents a volume-based average particle diameter (D50).
  • the cement additive of the present invention consisting of a by-product of lime-sulfur mixture may be used as it is in the form of solid particles, or it may be used in the form of a liquid in which the solid particles are dissolved or dispersed in a medium such as water. Also good.
  • various portland cements such as normal, early strength, ultra-early strength, low heat, medium heat, etc., various mixed cements obtained by mixing blast furnace slag, fly ash, or silica with these portland cements, limestone
  • various mixed cements obtained by mixing blast furnace slag, fly ash, or silica with these portland cements, limestone Examples include filler cement mixed with powder, blast furnace slow-cooled slag fine powder and the like, and Portland cement such as environmentally conscious cement (eco-cement) manufactured using municipal waste incineration ash and sewage sludge incineration ash as raw materials. In the present invention, one or more of these can be used.
  • the amount of the cement additive of the present invention used in cement concrete is not particularly limited, but is usually preferably 0.05 to 2 parts, more preferably 0.1 to 1 part, relative to 100 parts of cement.
  • the effects of the present invention that is, the fluidity retention effect, the hexavalent chromium reduction effect, and the self-shrinkage reduction effect may not be sufficiently obtained.
  • cement and a cement additive are blended to form a cement composition.
  • fine aggregates such as sand and coarse aggregates such as gravel, as well as expansion materials, rapid hardening materials, water reducing agents, AE water reducing agents, high performance Water reducing agent, high performance AE water reducing agent, antifoaming agent, thickener, conventional rust preventive agent, antifreeze agent, shrinkage reducing agent, setting modifier, clay minerals such as bentonite, anion exchanger such as hydrotalcite, blast furnace
  • a group consisting of admixtures such as slag such as granulated slag fine powder and blast furnace slow-cooled slag fine powder, limestone fine powder, etc. are used in a range that does not substantially impair the object of the present invention. It is possible.
  • the cement composition of the present invention may be partially or wholly mixed with the above components used therein.
  • Any existing apparatus can be used as a mixing apparatus for mixing various components.
  • a tilting cylinder mixer, an omni mixer, a Henschel mixer, a V-type mixer, a proshear mixer, a nauta mixer, and the like can be used.
  • the cement additive of the present invention is used as a grinding aid for cement clinker, the above-described effects of the present invention are more remarkably exhibited.
  • Example 1 Various cement additives A to G shown below were used.
  • each cement composition comprising cement and cement additive, 0.5 part is used for 100 parts of cement, the unit cement composition amount is 500 kg / m 3 , and the water / cement composition ratio is 33%.
  • 1.4 parts of the high performance water reducing agent was added to 100 parts of the cement composition. This concrete was confirmed for the change of slump with time, self-shrinkage, and reduction effect of hexavalent chromium. The results are also shown in Table 1.
  • Cement Ordinary Portland cement, Blaine specific surface area 3210 cm 2 / g, a commercially available product (Denka Co., Ltd., ordinary Portland cement) is used.
  • Cement additive A by-product of lime sulfur mixture, calcium sulfite hemihydrate content 82%, pH 10.5, ORP 30 mv, MgO content 1.0%.
  • Cement additive B lime sulfur mixture by-product, calcium sulfite hemihydrate content 80%, pH 10.0, ORP 35 mv, MgO content 1.0%.
  • Cement additive C by-product of lime sulfur mixture, calcium sulfite hemihydrate content 79%, pH 9.5, ORP 45 mv, MgO content 1.0%.
  • Cement additive D lime sulfur mixture by-product, calcium sulfite hemihydrate content 88%, pH 9.0, ORP 50 mv, MgO content 1.0%.
  • Cement additive E by-product of lime sulfur mixture, calcium sulfite hemihydrate content 76%, pH 10.0, ORP 35 mv, MgO content 0.5%.
  • Cement additive F Reagent grade 1 calcium sulfite hemihydrate, pH 7.7, ORP 100 mv, MgO content less than 0.1%.
  • Cement additive G Reagent grade 1 calcium sulfite hemihydrate, pH 10.0 (pH adjusted with reagent grade 1 calcium hydroxide), ORP 110 mV, MgO content less than 0.1%.
  • the cement additives A to E described above are obtained by changing the use ratios of quicklime, sulfur and water in various ways, and filtering each reaction solution obtained by reacting at 150 ° C. at a pressure of 5 atm in an autoclave with a filter press. Each solid is obtained by separating and removing the liquid and drying the resulting solid at 105 ° C. under reduced pressure.
  • the said cement additives F and G are obtained by using commercially available calcium sulfite hemihydrate different in grade 1.
  • Fine aggregate river sand from Himekawa, Niigata Prefecture, particle size: under sieve 5 mm, coarse particle ratio 2.82, specific gravity 2.64.
  • Coarse aggregate Crushed stone from Himekawa, Niigata Prefecture, maximum particle size 25 mm, coarse particle ratio 6.98, specific gravity 2.62.
  • High performance water reducing agent Polycarboxylate, commercially available (BASF, MELFLUX 2651 F).
  • ⁇ Test method> Change in slump with time Slump was measured according to JIS A 1150, and the amount of change in the measured value 30 minutes and 90 minutes after the kneading was examined.
  • Self-shrinkage Measured according to JCI Self-Shrink Research Committee report. Displayed as self-contracting strain at age 56 days.
  • Elution amount of hexavalent chromium A hexavalent chromium standard solution is diluted to prepare a solution having a hexavalent chromium concentration of 100 mg / l, and the hexavalent chromium solution is made to be 2 liters per 1 m 3 of concrete. The water was replaced with kneading water.
  • the amount of elution from fresh concrete that has not yet solidified and the amount of elution from hardened concrete were investigated.
  • the amount of elution from the fresh concrete was determined by adding hydrochloric acid to pure water from a sample obtained by filtering the supernatant obtained from bleeding water or centrifugation after 30 minutes of kneading, and a hydrogen ion concentration index of 5.8 or more. It was mixed with a solution having a volume ratio of 3 or less at a ratio of 10% by weight and measured by ICP emission spectroscopic analysis according to JIS K 0102.
  • the amount of elution from the hardened concrete was obtained by crushing hardened concrete after 28 days of age and using a sample 2 mm below. However, the residual concentration of hexavalent chromium was measured by ICP emission spectroscopic analysis according to JIS K0102.
  • Example 2 The same procedure as in Experimental Example 1 was conducted except that the cement additive A was used and the amount of the cement additive used was changed as shown in Table 2. The results are shown in Table 2.
  • cement additive and cement composition of the present invention By using the cement additive and cement composition of the present invention, good fluidity retention effect and self-shrinkage reduction effect can be obtained, and in addition, it exhibits the reducing action of hexavalent chromium that has both immediate effect and sustainability. It is suitable for a wide range of applications mainly in the civil engineering and construction industries.

Abstract

Provided are a cement additive and a cement composition that make it possible to obtain the effects of maintaining the favorable fluidity of cement concrete and reducing autogeneous shrinkage in addition to achieving effects such as immediately effective and long-lasting hexavalent chromium reduction action. (1) A cement additive containing calcium sulfite that is a byproduct of the production of a lime-sulfur mixture. (2) The cement additive indicated in (1), wherein the pH is 9.0 or more. (3) The cement additive indicated in (1) or (2), wherein the oxidation-reduction potential (ORP) is 50 mv or less. (4) One of the cement additives indicated in (1) to (3), wherein the MgO content is 0.5% or more. (5) A cement composition containing cement and one of the cement additives indicated in (1) to (4). (6) The cement composition indicated in (5), wherein 0.05-2 parts of the cement additive are added to 100 parts of cement. (7) The cement composition indicated in (5) or (6), wherein the cement is Portland cement.

Description

セメント添加剤及びセメント組成物Cement additive and cement composition
　本発明は、主に、土木・建築業界において使用されるセメント添加剤及びセメント組成物に関する。 The present invention mainly relates to a cement additive and a cement composition used in the civil engineering and construction industries.
　近年、セメントコンクリートの品質確保が以前にも増して難しくなっている。これは、セメント産業が各方面の産業副産物を原料に受け入れており、その受け入れ原単位が増していることが背景にある。これらの産業副産物に由来する微量成分が、セメントの品質に大きな影響を及ぼすためである。 In recent years, it has become more difficult to ensure the quality of cement concrete. This is due to the fact that the cement industry accepts various industrial by-products as raw materials, and the acceptance unit is increasing. This is because the trace components derived from these industrial by-products greatly affect the quality of cement.
　特に、微量成分の含有量の違いによって、流動性や強度発現性が大きく異なってくる。また、六価クロムの溶出量などにも大きな違いが出てくる。しかし、各方面の産業副産物を受け入れるというセメント産業の役割は、今後も益々求められるため、産業副産物を多量に処理しつつ、微量成分の影響を制御可能なセメントの品質設計手法が強く求められている。 Especially, fluidity and strength development vary greatly depending on the content of trace components. There are also significant differences in the elution amount of hexavalent chromium. However, the role of the cement industry in accepting industrial by-products in various fields will continue to be increasingly demanded, so there is a strong demand for cement quality design methods that can control the effects of trace components while processing large amounts of industrial by-products. Yes.
　亜硫酸カルシウムは、六価クロム還元剤として良く知られている（例えば、特許文献１～特許文献５）。特に、亜硫酸カルシウムは、ＳＯｘの吸収剤として生石灰などを使用するタイプの排煙脱硫装置における副生物として大量に得られることから、セッコウやセメントとともに使用する、重金属を含む土壌改良剤として広く使用されている。しかし、排煙脱硫装置における副生物として得られる亜硫酸カルシウムは、ｐＨは約４～７の酸性領域にある。 Calcium sulfite is well known as a hexavalent chromium reducing agent (for example, Patent Documents 1 to 5). In particular, calcium sulfite is widely used as a soil conditioner containing heavy metals used with gypsum and cement because it is obtained in large quantities as a by-product in the type of flue gas desulfurization equipment that uses quicklime as an SOx absorbent. ing. However, calcium sulfite obtained as a by-product in the flue gas desulfurization apparatus has a pH in the acidic region of about 4-7.
　また、アルカリ金属又はアルカリ土類金属などの亜硫酸絵は、セメントやモルタル材料におけるスランプロスを低減するセメント混和材としても知られている（特許文献６～特許文献１０）。しかし、ここで使用される亜硫酸カルシウムは、純度の高い工業的な薬品であり、そのｐＨは約８．０以下を有する中性塩である。 Also, sulfite paintings such as alkali metals or alkaline earth metals are also known as cement admixtures that reduce slump loss in cement and mortar materials (Patent Documents 6 to 10). However, calcium sulfite used here is a high-purity industrial chemical, and is a neutral salt having a pH of about 8.0 or less.
日本特開平１１－３０２６４４号公報Japanese Unexamined Patent Publication No. 11-302644 日本特開２００７－２４６３０６号公報Japanese Unexamined Patent Publication No. 2007-246306 日本特開２００８－１７４４３６号公報Japanese Unexamined Patent Publication No. 2008-174436 日本特開２０１０－２０１４０６号公報Japanese Unexamined Patent Publication No. 2010-201406 日本特開２０１２－２４７６３号公報Japanese Unexamined Patent Publication No. 2012-24863 日本特開平９－２９５８４３号公報Japanese Unexamined Patent Publication No. 9-295843 日本特開平１０－２６５２４９号公報Japanese Unexamined Patent Publication No. 10-265249 日本特開平１０－２９１８４４号公報Japanese Unexamined Patent Publication No. 10-291844 日本特開平１１－７９８１９号公報Japanese Unexamined Patent Publication No. 11-79819 日本特開平１１－７９８２２号公報Japanese Unexamined Patent Publication No. 11-79822
　本発明は、特定の亜硫酸カルシウムを使用することによって、セメントコンクリートの良好な流動性の保持効果や自己収縮低減効果が得られ、加えて、即効性と持続性を併せ持つ六価クロムの還元作用を発揮するセメント添加剤及びセメント組成物を提供することを目的とする。 In the present invention, by using a specific calcium sulfite, the good fluidity retention effect and self-shrinkage reduction effect of cement concrete can be obtained, and in addition, the reducing action of hexavalent chromium having both immediate effect and sustainability can be achieved. It aims at providing the cement additive and cement composition which exhibit.
　本発明者は、上記の目的を達成すべく鋭意研究を進めたところ、石灰硫黄合剤を製造する際の副産物である亜硫酸カルシウムを含有し、ｐＨが９．０以上を有し、好ましくは、酸化還元電位（ＯＲＰ）が５０ｍｖ以下であるセメント添加剤、及びこのセメント添加剤が添加されたセメント組成物が上記の目的を達成することを見出した。
　本発明は、上記の知見に基づくものであり、以下を要旨とする。
　すなわち、本発明は、（１）石灰硫黄合剤を製造する際の副産物である亜硫酸カルシウムを含有してなるセメント添加剤、（２）ｐＨが９．０以上である請求項１に記載のセメント添加剤、（３）酸化還元電位（ＯＲＰ）が５０ｍｖ以下である（１）又は（２）のセメント添加剤、（４）ＭｇＯ含有量が０．５％以上である（１）～（３）のいずれかのセメント添加剤、（５）セメントと（１）～（４）のいずれかのセメント添加剤を含有するセメント組成物、（６）セメント１００部に対して０．０５～２部添加してなる（５）のセメント組成物、である。（７）セメントがポルトランドセメントである（５）又は（６）に記載のセメント組成物。 The present inventor has conducted earnest research to achieve the above object, and contains calcium sulfite, which is a by-product in producing a lime-sulfur mixture, and has a pH of 9.0 or more, preferably, It has been found that a cement additive having an oxidation-reduction potential (ORP) of 50 mV or less and a cement composition to which the cement additive is added achieve the above object.
The present invention is based on the above findings and is summarized as follows.
That is, the present invention provides (1) a cement additive containing calcium sulfite, which is a by-product when producing a lime-sulfur mixture, and (2) a cement according to claim 1 having a pH of 9.0 or more. Additive, (3) redox potential (ORP) is 50 mV or less (1) or (2) cement additive, (4) MgO content is 0.5% or more (1) to (3) (5) Cement and a cement composition containing any one of the cement additives (1) to (4), (6) 0.05 to 2 parts added to 100 parts of cement (5) the cement composition. (7) The cement composition according to (5) or (6), wherein the cement is Portland cement.
　本発明のセメント添加剤を用いることにより、良好な流動性の保持効果や自己収縮低減効果が得られ、加えて、即効性と持続性を併せ持つ六価クロムの還元作用を発揮するなどの効果を奏する。 By using the cement additive of the present invention, good fluidity retention effect and self-shrinkage reduction effect are obtained, and in addition, effects such as exerting the reducing action of hexavalent chromium having both immediate effect and sustainability are exhibited. Play.
　以下、本発明を詳細に説明する。なお、本発明における、「部」や「パーセント（％）」は、特に規定しない限り質量基準で示す。また、本発明で云うセメントコンクリートとは、セメントペースト、セメントモルタル、及びコンクリートの総称である。
　さらに、本発明で云う亜硫酸カルシウムとは、亜硫酸カルシウム無水物、亜硫酸カルシウム半水和物を総称するものである。 Hereinafter, the present invention will be described in detail. In the present invention, “parts” and “percent (%)” are shown on a mass basis unless otherwise specified. The cement concrete referred to in the present invention is a general term for cement paste, cement mortar, and concrete.
Furthermore, the calcium sulfite referred to in the present invention is a general term for calcium sulfite anhydrous and calcium sulfite hemihydrate.
　本発明のセメント添加剤は、石灰硫黄合剤を製造する際の副産物である亜硫酸カルシウムを含有し、ｐＨが９．０以上を有する。石灰硫黄合剤は、原料である、生石灰と硫黄と水とを使用割合やオートクレーブにおける反応条件により、種々の組成割合や特性を有するものが得られる。すなわち、原料である、生石灰と：硫黄：水の割合は、生石灰１部に対して好ましくは、硫黄が１．２～３部、水が２．５～５部が使用され、特に好ましくは、硫黄が１．５～２部、水が３～４部が使用される。また、反応は、好ましくは３．５～１０気圧の加圧条件で、好ましくは、1４０～１８０℃で行われる。反応は、オートクレーブ中にておこなわれるのが好ましい。 The cement additive of the present invention contains calcium sulfite, which is a by-product when producing a lime sulfur mixture, and has a pH of 9.0 or more. The lime-sulfur mixture has various composition ratios and characteristics depending on the use ratio of the raw lime, sulfur, and water, and the reaction conditions in the autoclave. That is, the ratio of quick lime and sulfur: water as raw materials is preferably 1.2 to 3 parts of sulfur and 2.5 to 5 parts of water with respect to 1 part of quick lime, particularly preferably 1.5 to 2 parts of sulfur and 3 to 4 parts of water are used. The reaction is preferably carried out under a pressurized condition of 3.5 to 10 atmospheres, preferably 140 to 180 ° C. The reaction is preferably carried out in an autoclave.
　石灰硫黄合剤を製造する際の副産物である亜硫酸カルシウムは、生石灰と硫黄と水との反応混合物をフィルタープレスなどにより固液分離することにより、その主成分である多流化カルシウムは液体として分離され、所謂石灰硫黄合剤となる。一方、残りの固体状物は、減圧又は大気中にて、好ましくは５０～１２０℃、より好ましくは７０～１０５℃で乾燥させる。得られた固体状の副産物を特に精製することのなく、粉末Ｘ線回折法で同定すると、亜硫酸カルシウム半水和物が確認される。この副産物の乾燥質量１００部中の亜硫酸カルシウム半水和物の含有量は、通常、７５％～９５％以上含まれる。この副産物の亜硫酸カルシウムは、原料である、生石灰と硫黄と水とを使用割合やオートクレーブにおける反応条件により、ｐＨを含めて種々の特性を有するものが得られる。 Calcium sulfite, a by-product of producing lime-sulfur mixture, separates the reaction mixture of quick lime, sulfur, and water by solid-liquid separation with a filter press, etc., so that the mainstream multi-fluidized calcium is separated as a liquid It becomes a so-called lime sulfur mixture. On the other hand, the remaining solid substance is dried at 50 to 120 ° C., more preferably 70 to 105 ° C. under reduced pressure or in the air. When the obtained solid by-product is identified by powder X-ray diffraction without any particular purification, calcium sulfite hemihydrate is confirmed. The content of calcium sulfite hemihydrate in 100 parts by weight of this by-product is usually 75% to 95% or more. This by-product calcium sulfite has various properties including pH depending on the use ratio of raw lime, sulfur and water, and reaction conditions in the autoclave.
　本発明では、石灰硫黄合剤を製造する際の副産物である亜硫酸カルシウムを含有するセメント添加剤が、ｐＨ９．０以上のアルカリ性領域を有することが重要である。ｐＨが９．０未満では、本発明の効果、すなわち、流動性の保持効果や六価クロムの還元効果、さらには自己収縮の低減効果が十分に得られない場合がある。なかでも、セメント添加剤のｐＨは、１０．０以上が好ましい。このｐＨは大きい方が好ましいが、取扱いの安全上の観点から、１３．０以下が好ましい。
　なお、ここにおけるｐＨは、石灰硫黄合剤の副産物である亜硫酸カルシウムを含有するセメント添加剤１０ｇに純水１００ｍｌを加え、撹拌した後の上澄み液のｐＨをイオン電極式ｐＨ計を用いて測定される。 In the present invention, it is important that the cement additive containing calcium sulfite, which is a by-product when producing a lime sulfur mixture, has an alkaline region having a pH of 9.0 or more. When the pH is less than 9.0, the effects of the present invention, that is, the fluidity retention effect, the hexavalent chromium reduction effect, and the self-shrinkage reduction effect may not be sufficiently obtained. Among these, the pH of the cement additive is preferably 10.0 or more. The pH is preferably larger, but is preferably 13.0 or less from the viewpoint of handling safety.
Here, the pH is measured by adding 100 ml of pure water to 10 g of cement additive containing calcium sulfite, which is a byproduct of the lime sulfur mixture, and stirring the pH of the supernatant liquid using an ion electrode pH meter. The
　また、石灰硫黄合剤を製造する際の副産物を含有する本発明のセメント添加剤の酸化還元電位（ＯＲＰ）は、５０ｍｖ以下であるのが好ましい。一方、試薬の亜硫酸カルシウムのＯＲＰは、ほぼ１００ｍｖである。セメント添加剤のＯＲＰが５０ｍｖ以下の範囲にないと、本発明の効果、すなわち、流動性の保持効果や六価クロムの還元効果、さらには自己収縮の低減効果が十分に得られない場合がある。なかでも、ＯＲＰは、３５ｍｖ以下が好ましい。このＯＲＰは小さい方が好ましく、ＯＲＰの下限値については、特に限定はなく、本発明の効果を阻害しない範囲であればよい。
　なお、本発明で言うＯＲＰとは、セメント添加剤１０ｇに純水１００ｍｌを加え、撹拌した後の上澄み液のＯＲＰを意味する。 Moreover, it is preferable that the oxidation-reduction potential (ORP) of the cement additive of this invention containing the by-product at the time of manufacturing a lime sulfur mixture is 50 mv or less. On the other hand, the ORP of the reagent calcium sulfite is approximately 100 mV. If the ORP of the cement additive is not in the range of 50 mv or less, the effects of the present invention, that is, the fluidity retention effect, the hexavalent chromium reduction effect, and the self-shrinkage reduction effect may not be sufficiently obtained. . Especially, ORP has preferable 35 mv or less. The ORP is preferably small, and the lower limit value of the ORP is not particularly limited as long as it does not impair the effects of the present invention.
In addition, ORP said by this invention means ORP of the supernatant liquid after adding 100 ml of pure waters to 10 g of cement additives, and stirring.
　石灰硫黄合剤の副産物を含有する本発明のセメント添加剤には、ＭｇＯ換算で０．５～２．０％の範囲でＭｇが含まれるのが好ましい。Ｍｇの含有量がＭｇＯ換算で０．５％未満であると、本発明の効果、すなわち、流動性の保持効果や六価クロムの還元効果、さらには自己収縮の低減効果が十分に得られない場合がある。なかでも、Ｍｇの含有量は、０．７以上が好ましく、１．０以上が特に好ましい。Ｍｇの含有量は大きい方が好ましいが、メント水和物中のＣａと置換して変質を促す場合があるため、２．０以下が好ましい。 The cement additive of the present invention containing a lime-sulfur mixture by-product preferably contains Mg in a range of 0.5 to 2.0% in terms of MgO. When the Mg content is less than 0.5% in terms of MgO, the effects of the present invention, that is, the fluidity retention effect, the hexavalent chromium reduction effect, and the self-shrinkage reduction effect are not sufficiently obtained. There is a case. Of these, the Mg content is preferably 0.7 or more, and more preferably 1.0 or more. The Mg content is preferably larger, but is preferably 2.0 or less because it may be substituted for Ca in mentor hydrate to promote alteration.
　本発明のセメント添加剤に含有される石灰硫黄合剤の副産物の粒度は、特に限定されるものではないが、平均粒径で５～３０μｍが好ましく、１０～２０μｍがより好ましい。また、ブレーン比表面積で２,０００～８,０００ｃｍ２／ｇが好ましく、３５００～５０００ｃｍ２／ｇがより好ましい。ブレーン比表面積が２０００ｃｍ２／ｇ未満では、六価クロムの還元効果について即効性が充分に得られない場合がある。また、８０００ｃｍ２／ｇを超えると六価クロムの還元効果についてと持続性が充分に得られない場合がある。なお、ここにおける平均粒径は、体積基準の平均粒径（Ｄ５０）を表す。
　石灰硫黄合剤の副産物からなる本発明のセメント添加剤は、固体の粒子状でそのまま使用してもよく、また、固体の粒子状を水などの媒体に溶解又は分散させた液状で使用してもよい。 The particle size of the byproduct of the lime-sulfur mixture contained in the cement additive of the present invention is not particularly limited, but the average particle size is preferably 5 to 30 μm, more preferably 10 to 20 μm. Also, 2,000 ~ 8,000cm 2 / g are preferred in Blaine specific surface area, more preferably 3500 ~ 5000cm 2 / g. When the specific surface area of the brane is less than 2000 cm 2 / g, the immediate effect may not be sufficiently obtained for the reduction effect of hexavalent chromium. Moreover, when it exceeds 8000 cm < 2 > / g, sustainability may not fully be acquired about the reduction effect of hexavalent chromium. In addition, the average particle diameter here represents a volume-based average particle diameter (D50).
The cement additive of the present invention consisting of a by-product of lime-sulfur mixture may be used as it is in the form of solid particles, or it may be used in the form of a liquid in which the solid particles are dissolved or dispersed in a medium such as water. Also good.
　本発明で使用するセメントとしては、普通、早強、超早強、低熱、中庸熱などの各種ポルトランドセメントや、これらポルトランドセメントに、高炉スラグ、フライアッシュ、又はシリカを混合した各種混合セメント、石灰石粉末や高炉徐冷スラグ微粉末などを混合したフィラーセメント、並びに、都市ゴミ焼却灰や下水汚泥焼却灰を原料として製造された環境調和型セメント（エコセメント）などのポルトランドセメントが挙げられる。本発明では、これらのうちの一種又は二種以上が使用可能である。 As the cement used in the present invention, various portland cements such as normal, early strength, ultra-early strength, low heat, medium heat, etc., various mixed cements obtained by mixing blast furnace slag, fly ash, or silica with these portland cements, limestone Examples include filler cement mixed with powder, blast furnace slow-cooled slag fine powder and the like, and Portland cement such as environmentally conscious cement (eco-cement) manufactured using municipal waste incineration ash and sewage sludge incineration ash as raw materials. In the present invention, one or more of these can be used.
　セメントコンクリートにおける本発明のセメント添加剤の使用量は、特に限定されるものではないが、通常、セメント１００部に対して０．０５～２部が好ましく、０．１～１部がより好ましい。セメント添加剤の使用量が少ないと、本発明の効果、すなわち、流動性の保持効果や六価クロムの還元効果、さらには自己収縮の低減効果が十分に得られない場合がある。
　本発明では、セメントとセメント添加剤を配合してセメント組成物とする。 The amount of the cement additive of the present invention used in cement concrete is not particularly limited, but is usually preferably 0.05 to 2 parts, more preferably 0.1 to 1 part, relative to 100 parts of cement. When the amount of the cement additive used is small, the effects of the present invention, that is, the fluidity retention effect, the hexavalent chromium reduction effect, and the self-shrinkage reduction effect may not be sufficiently obtained.
In the present invention, cement and a cement additive are blended to form a cement composition.
　本発明のセメント組成物では、セメント及びセメント添加剤に加えて、砂などの細骨材や砂利などの粗骨材、更には、膨張材、急硬材、減水剤、ＡＥ減水剤、高性能減水剤、高性能ＡＥ減水剤、消泡剤、増粘剤、従来の防錆剤、防凍剤、収縮低減剤、凝結調整剤、ベントナイトなどの粘土鉱物、ハイドロタルサイトなどのアニオン交換体、高炉水砕スラグ微粉末や高炉徐冷スラグ微粉末などのスラグ、石灰石微粉末などの混和材料からなる群のうちの一種又は二種以上を、本発明の目的を実質的に阻害しない範囲で併用することが可能である。 In the cement composition of the present invention, in addition to cement and cement additives, fine aggregates such as sand and coarse aggregates such as gravel, as well as expansion materials, rapid hardening materials, water reducing agents, AE water reducing agents, high performance Water reducing agent, high performance AE water reducing agent, antifoaming agent, thickener, conventional rust preventive agent, antifreeze agent, shrinkage reducing agent, setting modifier, clay minerals such as bentonite, anion exchanger such as hydrotalcite, blast furnace One or two or more of a group consisting of admixtures such as slag such as granulated slag fine powder and blast furnace slow-cooled slag fine powder, limestone fine powder, etc. are used in a range that does not substantially impair the object of the present invention. It is possible.
　本発明のセメント組成物は、そこで使用される上記の成分について、予め一部あるいは全部を混合しておいても差し支えない。各種成分を混合するための混合装置としては、既存の如何なる装置も使用可能であり、例えば、傾胴ミキサ、オムニミキサ、ヘンシェルミキサ、Ｖ型ミキサ、プロシェアミキサ及びナウタミキサ等の使用が可能である。
　なお、本発明のセメント添加剤は、セメントクリンカーの粉砕助剤として用いる場合には、上記した本発明の効果がより顕著には発揮される。 The cement composition of the present invention may be partially or wholly mixed with the above components used therein. Any existing apparatus can be used as a mixing apparatus for mixing various components. For example, a tilting cylinder mixer, an omni mixer, a Henschel mixer, a V-type mixer, a proshear mixer, a nauta mixer, and the like can be used.
In addition, when the cement additive of the present invention is used as a grinding aid for cement clinker, the above-described effects of the present invention are more remarkably exhibited.
　以下、実施例、比較例を挙げて本発明を更に具体的に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these.
「実験例１」
　下記に示す種々のセメント添加剤Ａ～Ｇを使用した。各セメント添加剤をセメントとセメント添加剤からなるセメント組成物において、セメント１００部に対して０．５部使用し、単位セメント組成物量が５００ｋｇ／ｍ３、水／セメント組成物比が３３％、全骨材容積に対する細骨材容積比（ｓ／ａ）が４６％、空気量４．５％、スランプ２１ｃｍのコンクリートを調製した。この際、高性能減水剤をセメント組成物１００部に対して１．４部添加した。このコンクリートについて、スランプの経時変化、自己収縮、六価クロムの還元効果の確認を行った。結果を表１に併記する。 "Experiment 1"
Various cement additives A to G shown below were used. In each cement composition comprising cement and cement additive, 0.5 part is used for 100 parts of cement, the unit cement composition amount is 500 kg / m 3 , and the water / cement composition ratio is 33%. Concrete having a fine aggregate volume ratio (s / a) to the total aggregate volume of 46%, an air amount of 4.5%, and a slump of 21 cm was prepared. At this time, 1.4 parts of the high performance water reducing agent was added to 100 parts of the cement composition. This concrete was confirmed for the change of slump with time, self-shrinkage, and reduction effect of hexavalent chromium. The results are also shown in Table 1.
＜使用材料＞
セメント：普通ポルトランドセメント、ブレーン比表面積３２１０ｃｍ２／ｇ、市販品（デンカ社製、普通ポルトランドセメント）を使用。
セメント添加剤Ａ：石灰硫黄合剤の副産物、亜硫酸カルシウム半水和物の含有量８２％、ｐＨ１０．５、ＯＲＰ３０ｍｖ、ＭｇＯ含有量１．０％。
セメント添加剤Ｂ：石灰硫黄合剤の副産物、亜硫酸カルシウム半水和物の含有量８０％、ｐＨ１０．０、ＯＲＰ３５ｍｖ、ＭｇＯ含有量が１．０％。
セメント添加剤Ｃ：石灰硫黄合剤の副産物、亜硫酸カルシウム半水和物の含有量７９％、ｐＨ９．５、ＯＲＰ４５ｍｖ、ＭｇＯ含有量１．０％。
セメント添加剤Ｄ：石灰硫黄合剤の副産物、亜硫酸カルシウム半水和物の含有量８８％、ｐＨ９．０、ＯＲＰ５０ｍｖ、ＭｇＯ含有量１．０％。
セメント添加剤Ｅ：石灰硫黄合剤の副産物、亜硫酸カルシウム半水和物の含有量７６％、ｐＨ１０．０、ＯＲＰ３５ｍｖ、ＭｇＯ含有量０．５％。
セメント添加剤Ｆ：試薬１級の亜硫酸カルシウム半水和物、ｐＨ７．７、ＯＲＰ１００ｍｖ、ＭｇＯ含有量０．１％未満。
セメント添加剤Ｇ：試薬１級の亜硫酸カルシウム半水和物、ｐＨが１０.０（試薬１級の水酸化カルシウムでｐＨを調整）、ＯＲＰ１１０ｍｖ、ＭｇＯ含有量０．１％未満。
　上記セメント添加剤Ａ～Ｅは、生石灰と硫黄と水の使用割合を種々に変え、オートクレーブ中で５気圧の圧力で１５０℃で反応させて得られるそれぞれの反応液を、フィルタープレスで濾過して液体を分離除去し、得られる固体状物を減圧下、１０５℃にて乾燥させることで得られた各々の固体状物である。なお、上記セメント添加剤Ｆ、Ｇは、市販の試薬１級の異なる亜硫酸カルシウム半水和物を使用して得られるものである。 <Materials used>
Cement: Ordinary Portland cement, Blaine specific surface area 3210 cm 2 / g, a commercially available product (Denka Co., Ltd., ordinary Portland cement) is used.
Cement additive A: by-product of lime sulfur mixture, calcium sulfite hemihydrate content 82%, pH 10.5, ORP 30 mv, MgO content 1.0%.
Cement additive B: lime sulfur mixture by-product, calcium sulfite hemihydrate content 80%, pH 10.0, ORP 35 mv, MgO content 1.0%.
Cement additive C: by-product of lime sulfur mixture, calcium sulfite hemihydrate content 79%, pH 9.5, ORP 45 mv, MgO content 1.0%.
Cement additive D: lime sulfur mixture by-product, calcium sulfite hemihydrate content 88%, pH 9.0, ORP 50 mv, MgO content 1.0%.
Cement additive E: by-product of lime sulfur mixture, calcium sulfite hemihydrate content 76%, pH 10.0, ORP 35 mv, MgO content 0.5%.
Cement additive F: Reagent grade 1 calcium sulfite hemihydrate, pH 7.7, ORP 100 mv, MgO content less than 0.1%.
Cement additive G: Reagent grade 1 calcium sulfite hemihydrate, pH 10.0 (pH adjusted with reagent grade 1 calcium hydroxide), ORP 110 mV, MgO content less than 0.1%.
The cement additives A to E described above are obtained by changing the use ratios of quicklime, sulfur and water in various ways, and filtering each reaction solution obtained by reacting at 150 ° C. at a pressure of 5 atm in an autoclave with a filter press. Each solid is obtained by separating and removing the liquid and drying the resulting solid at 105 ° C. under reduced pressure. In addition, the said cement additives F and G are obtained by using commercially available calcium sulfite hemihydrate different in grade 1.
細骨材：新潟県姫川産の川砂、粒径：篩５ｍｍ下、粗粒率２.８２、比重２.６４。
粗骨材：新潟県姫川産の砕石、最大粒径２５ｍｍ、粗粒率６．９８、比重２.６２。
高性能減水剤：ポリカルボン酸塩系、市販品（BASF、MELFLUX 2651 F）。 Fine aggregate: river sand from Himekawa, Niigata Prefecture, particle size: under sieve 5 mm, coarse particle ratio 2.82, specific gravity 2.64.
Coarse aggregate: Crushed stone from Himekawa, Niigata Prefecture, maximum particle size 25 mm, coarse particle ratio 6.98, specific gravity 2.62.
High performance water reducing agent: Polycarboxylate, commercially available (BASF, MELFLUX 2651 F).
＜試験方法＞
スランプの経時変化：ＪＩＳ Ａ １１５０に準じてスランプを測定し、練り上がり直後から３０分後および９０分後測定値の変化量を調べた。
自己収縮：ＪＣＩ自己収縮研究委員会報告書に準じて測定。材齢５６日における自己収縮ひずみとして表示。
六価クロムの溶出量：六価クロム標準溶液を希釈して、六価クロム濃度が１００ｍｇ／ｌの溶液を調製し、この六価クロム溶液をコンクリート１ｍ３に対して２リットルとなるようにコンクリートの練り水に置換して加えた。まだ固まらないフレッシュコンクリートからの溶出量と、硬化したコンクリートからの溶出量を調べた。
　フレッシュコンクリートからの溶出量は、練りあがり３０分後にブリーディング水や遠心分離より得られる上澄みをろ過することで得た試料を、純水に塩酸を加えて水素イオン濃度指数が５．８以上６．３以下となるようにした溶液と重量体積比１０％の割合で混合し、ＪＩＳ　Ｋ　０１０２に準じてＩＣＰ発光分光分析法により測定した。
　硬化コンクリートからの溶出量は、材齢２８日後の硬化コンクリートを破砕し、２ｍｍ下の試料を用いた。ただし、六価クロムの残存濃度は、ＪＩＳ　Ｋ　０１０２に準じ、ＩＣＰ発光分光分析法により測定した。 <Test method>
Change in slump with time: Slump was measured according to JIS A 1150, and the amount of change in the measured value 30 minutes and 90 minutes after the kneading was examined.
Self-shrinkage: Measured according to JCI Self-Shrink Research Committee report. Displayed as self-contracting strain at age 56 days.
Elution amount of hexavalent chromium: A hexavalent chromium standard solution is diluted to prepare a solution having a hexavalent chromium concentration of 100 mg / l, and the hexavalent chromium solution is made to be 2 liters per 1 m 3 of concrete. The water was replaced with kneading water. The amount of elution from fresh concrete that has not yet solidified and the amount of elution from hardened concrete were investigated.
The amount of elution from the fresh concrete was determined by adding hydrochloric acid to pure water from a sample obtained by filtering the supernatant obtained from bleeding water or centrifugation after 30 minutes of kneading, and a hydrogen ion concentration index of 5.8 or more. It was mixed with a solution having a volume ratio of 3 or less at a ratio of 10% by weight and measured by ICP emission spectroscopic analysis according to JIS K 0102.
The amount of elution from the hardened concrete was obtained by crushing hardened concrete after 28 days of age and using a sample 2 mm below. However, the residual concentration of hexavalent chromium was measured by ICP emission spectroscopic analysis according to JIS K0102.
Figure JPOXMLDOC01-appb-T000001
 ND：検出せず
Figure JPOXMLDOC01-appb-T000001
 ND: Not detected
　表１より、本発明のセメント添加剤を使用することにより、中性の亜硫酸カルシウム半水和物と比較すると、流動性の保持効果に優れ、六価クロムの還元効果も即効性及び持続性の両立が図られ、しかも、自己収縮も低減されていることがわかる。また、中性の亜硫酸カルシウム半水和物からなるセメント添加剤ＧのｐＨを調整することでは、本発明と同様の効果が得られないことが分かる。 From Table 1, by using the cement additive of the present invention, compared with neutral calcium sulfite hemihydrate, the fluidity retention effect is excellent, and the reduction effect of hexavalent chromium is immediate and long-lasting. It can be seen that compatibility is achieved and self-shrinkage is also reduced. Moreover, it turns out that the effect similar to this invention is not acquired by adjusting the pH of the cement additive G which consists of neutral calcium sulfite hemihydrate.
「実験例２」
　セメント添加剤Ａを使用し、セメント添加剤の使用量を表２に示すように変化したこと以外は実験例１と同様に行った。結果を表２に示す。 "Experimental example 2"
The same procedure as in Experimental Example 1 was conducted except that the cement additive A was used and the amount of the cement additive used was changed as shown in Table 2. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
 ND：検出せず
Figure JPOXMLDOC01-appb-T000002
 ND: Not detected
　表２より、本発明のセメント添加剤を適量使用することにより、流動性の保持効果が得られ、六価クロムの還元効果も即効性および持続性の両立が図られ、しかも、自己収縮も低減されていることがわかる。 From Table 2, by using an appropriate amount of the cement additive of the present invention, a fluidity retention effect can be obtained, a reduction effect of hexavalent chromium can be achieved both with immediate effect and sustainability, and self-shrinkage is also reduced. You can see that
　本発明のセメント添加剤及びセメント組成物を使用することにより、良好な流動性の保持効果や自己収縮低減効果が得られ、加えて、即効性と持続性を併せ持つ六価クロムの還元作用を発揮するなどの効果を奏するため、主に、土木・建築業界等において広範な用途に適する。 By using the cement additive and cement composition of the present invention, good fluidity retention effect and self-shrinkage reduction effect can be obtained, and in addition, it exhibits the reducing action of hexavalent chromium that has both immediate effect and sustainability. It is suitable for a wide range of applications mainly in the civil engineering and construction industries.

Claims (7)

  1. 　石灰硫黄合剤を製造する際の副産物である亜硫酸カルシウムを含有してなるセメント添加剤。 A cement additive containing calcium sulfite which is a by-product when producing a lime-sulfur mixture.
  2. 　ｐＨが９．０以上である、請求項１に記載のセメント添加剤。 The cement additive according to claim 1, wherein the pH is 9.0 or more.
  3. 　酸化還元電位（ＯＲＰ）が５０ｍｖ以下である、請求項１又は２に記載のセメント添加剤。 The cement additive according to claim 1 or 2, wherein the redox potential (ORP) is 50 mV or less.
  4. 　ＭｇＯ含有量が０．５％～２．０％である、請求項１～３のいずれか１項に記載のセメント添加剤。 The cement additive according to any one of claims 1 to 3, wherein the MgO content is 0.5% to 2.0%.
  5. 　セメントと請求項１～４のいずれか１項に記載のセメント添加剤を含有するセメント組成物。 A cement composition containing cement and the cement additive according to any one of claims 1 to 4.
  6. 　セメント添加剤がセメント１００部に対して０．０５～２部である請求項５に記載のセメント組成物。 The cement composition according to claim 5, wherein the cement additive is 0.05 to 2 parts per 100 parts of cement.
  7. 　セメントがポルトランドセメントである、請求項５又は６に記載のセメント組成物。 The cement composition according to claim 5 or 6, wherein the cement is Portland cement.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020002269A (en) * 2018-06-28 2020-01-09 宇部興産株式会社 Soil improvement material and soil improvement method
CN111344263A (en) * 2017-11-10 2020-06-26 赵炳学 Cement additive and its production method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55129211A (en) * 1979-03-28 1980-10-06 Tomono Noyaku Kk Agent for controlling blossom blight of apple
JP2008174436A (en) * 2007-01-22 2008-07-31 Kajima Corp Manufacturing process of modified cementious material

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55129211A (en) * 1979-03-28 1980-10-06 Tomono Noyaku Kk Agent for controlling blossom blight of apple
JP2008174436A (en) * 2007-01-22 2008-07-31 Kajima Corp Manufacturing process of modified cementious material

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111344263A (en) * 2017-11-10 2020-06-26 赵炳学 Cement additive and its production method
JP2020002269A (en) * 2018-06-28 2020-01-09 宇部興産株式会社 Soil improvement material and soil improvement method

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