JP6509586B2 - Salt damage control admixture and reinforced concrete salt damage control method - Google Patents

Salt damage control admixture and reinforced concrete salt damage control method Download PDF

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JP6509586B2
JP6509586B2 JP2015041451A JP2015041451A JP6509586B2 JP 6509586 B2 JP6509586 B2 JP 6509586B2 JP 2015041451 A JP2015041451 A JP 2015041451A JP 2015041451 A JP2015041451 A JP 2015041451A JP 6509586 B2 JP6509586 B2 JP 6509586B2
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JP2016160146A (en
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樋口 隆行
隆行 樋口
将貴 宇城
将貴 宇城
聖一 寺崎
聖一 寺崎
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Denka Co Ltd
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Denki Kagaku Kogyo KK
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Description

本発明は、土木・建築分野で使用される鉄筋コンクリートの塩害対策方法および塩害対策用混和材に関する。   [Technical Field] The present invention relates to a method for preventing salt damage of reinforced concrete used in the field of civil engineering and construction and an additive for salt protection.

コンクリートのひび割れは、塩化物の浸透や中性化の進行を加速させ、鉄筋腐食に伴うコンクリート片の剥離や落下を誘発させる。特に沿岸部や道路関連のコンクリートでは、海からの飛来塩分や凍結防止剤の散布によって塩害が生じやすく、コンクリートのひび割れを低減する材料や技術の開発が進んでいる(特許文献1)。
また、塩害対策としてカルシウムフェロアルミネート化合物が有効であることが知られている(特許文献2)。
Cracking of concrete accelerates the progress of chloride penetration and neutralization, and induces peeling and falling of concrete fragments associated with rebar corrosion. Particularly in coastal areas and road-related concrete, salt damage is likely to occur by the dispersion of salt and antifreeze agents from the sea, and development of materials and techniques for reducing cracks in concrete is in progress (Patent Document 1).
Moreover, it is known that a calcium ferroaluminate compound is effective as a countermeasure against salt damage (Patent Document 2).

特開2001−64054号公報JP 2001-64054 A WO2011/108159号パンフレットWO 2011/108159 brochure

本発明は、塩化物浸透抑制効果とひび割れ抵抗性を有する塩害対策用混和材および鉄筋コンクリートの塩害対策方法を提供する。 The present invention provides a salt damage preventing admixture having a chloride penetration suppressing effect and cracking resistance, and a salt damage preventing method for reinforced concrete.

すなわち、本発明は、(1)CaO原料、Al原料、およびFe原料を混合したものを熱処理して得られ、カルシウムアルミノフェライト、および遊離石灰の合計100質量部中、カルシウムアルミノフェライトを30〜90質量部、遊離石灰を10〜70質量部の割合で含有する熱処理物を粉砕してなる塩害対策用混和材、(2)CaO原料、Al原料、およびFe原料に、さらにCaSO原料を混合したものを熱処理または後添加して得られ、カルシウムアルミノフェライト、遊離石灰、および無水石膏の合計100質量部中、カルシウムアルミノフェライトを20〜60質量部、遊離石灰を20〜70質量部、無水石膏を10質量部以下の割合で含有する熱処理物を粉砕してなる(1)の塩害対策用混和材、(3)熱処理物を炭酸化処理してなる(1)または(2)の塩害対策用混和材、(4)(1)〜(3)のいずれかの塩害対策用混和材をコンクリートに配合してなる鉄筋コンクリートの塩害対策方法、(5)塩害対策用混和材をコンクリート中のセメントに対してカルシウムアルミノフェライト含有量が10〜20質量%となるようにコンクリートに配合してなる(4)の鉄筋コンクリートの塩害対策方法、である。 That is, the present invention is obtained by heat treating a mixture of (1) CaO raw material, Al 2 O 3 raw material, and Fe 2 O 3 raw material, calcium in a total of 100 parts by mass of calcium aluminoferrite and free lime Admixture for preventing salt damage formed by grinding a heat-treated product containing 30 to 90 parts by mass of aluminoferrite and 10 to 70 parts by mass of free lime, (2) CaO raw material, Al 2 O 3 raw material, and Fe 2 Heat treatment or post-addition of a mixture of a CaSO 4 raw material to an O 3 raw material, 20 to 60 parts by weight of calcium aluminoferrite in 100 parts by weight of total of calcium aluminoferrite, free lime, and anhydrous gypsum Salt damage countermeasure of (1) formed by grinding a heat-treated product containing 20 to 70 parts by mass of free lime and 10 parts by mass or less of anhydrous gypsum Admixtures, (3) Additives for salinity prevention of (1) or (2) obtained by carbonation treatment of heat-treated product, and (4) (1) (1) to (3) The method for preventing salt damage of reinforced concrete compounded in concrete, (5) The additive for preventing salt damage is mixed in concrete so that the content of calcium aluminoferrite is 10 to 20 mass% with respect to the cement in the concrete ( 4) The method of measures against salt damage of reinforced concrete.

本発明により、塩化物を含む凍結防止材を散布しても鉄筋コンクリートの膨張率が高く、塩害によるひび割れ発生を防止することが可能となるなどの効果を奏する。   ADVANTAGE OF THE INVENTION Even if it spread | diffuses the antifreeze material containing a chloride by this invention, the expansion coefficient of reinforced concrete is high, and it is effective in the ability to prevent the crack generation | occurrence | production by salt damage etc. being exhibited.

本発明で使用される、部、%は、特に規定しない限り質量基準である。
また、本発明で云うコンクリートとは、セメントペースト、セメントモルタル、およびセメントコンクリートを総称するものである。
Parts,% used in the present invention are by mass unless otherwise specified.
Further, the concrete referred to in the present invention is a generic term for cement paste, cement mortar and cement concrete.

本発明の熱処理物とは、CaO原料、Al原料、およびFe原料、あるいは、これら原料に、さらにCaSO原料を混合したものを熱処理して得られる。 The heat-treated product of the present invention is obtained by heat-treating a CaO raw material, an Al 2 O 3 raw material, an Fe 2 O 3 raw material, or a mixture of these raw materials and a CaSO 4 raw material.

CaO原料としては、石灰石や消石灰などが挙げられる。Al原料としては、ボーキサイトやアルミ残灰などが挙げられる。Fe原料としては銅カラミや市販の酸化鉄などが挙げられる。CaSO原料としては二水石膏、半水石膏および無水石膏などが挙げられる。
これらの原料には不純物を含む場合があるが、本発明の効果を阻害しない範囲内では特に問題とはならない。不純物としては、SiO、MgO、TiO、ZrO、MnO、P、NaO、KO、LiO、硫黄、フッ素、塩素などが挙げられる。
Examples of CaO raw materials include limestone and slaked lime. Examples of Al 2 O 3 raw materials include bauxite and aluminum residual ash. As a Fe 2 O 3 raw material, a copper calami, a commercially available iron oxide, etc. are mentioned. Examples of the CaSO 4 raw material include gypsum dihydrate, gypsum hemihydrate and gypsum anhydrite.
Although these raw materials may contain impurities in some cases, they do not cause any particular problems as long as the effects of the present invention are not impaired. As the impurities, SiO 2 , MgO, TiO 2 , ZrO 2 , MnO, P 2 O 5 , Na 2 O, K 2 O, Li 2 O, sulfur, fluorine, chlorine and the like can be mentioned.

本発明において、CaO原料、Al原料、およびFe原料、あるいは、CaO原料、Al原料、およびFe原料に、さらにCaSO原料を混合したものを熱処理する方法は、特に限定されるものではない。
例えば、電気炉やキルンなどを用いて、1000〜1600℃の温度で焼成することが好ましく、1200〜1500℃がより好ましい。1000℃未満では、練り混ぜ直後のコンクリートの流動性の確保が難しい場合や初期強度の発現性が充分でない場合があり、1600℃を超えると無水石膏が分解する場合や初期強度の発現性が不十分になる場合がある。熱処理の時間は、その温度にもよるが、最高温度での保持時間は0〜2.0時間が好ましく、0.25〜1.75時間がより好ましい。
In the present invention, the CaO raw material, the Al 2 O 3 raw material, and the Fe 2 O 3 raw material, or the CaO raw material, the Al 2 O 3 raw material, and the Fe 2 O 3 raw material further mixed with CaSO 4 raw material are heat-treated The method is not particularly limited.
For example, using an electric furnace, a kiln, etc., it is preferable to bake at the temperature of 1000-1600 degreeC, and 1200-1500 degreeC is more preferable. If it is less than 1000 ° C., it may be difficult to ensure the fluidity of the concrete immediately after mixing, or the onset of the initial strength may not be sufficient. If it exceeds 1600 ° C., the anhydrite may decompose or the onset of the initial strength may not be obtained. It may be enough. The heat treatment time depends on the temperature, but the retention time at the maximum temperature is preferably 0 to 2.0 hours, and more preferably 0.25 to 1.75 hours.

本発明の熱処理物には、カルシウムアルミノフェライト、遊離石灰や無水石膏が含まれる。
本発明で云う遊離石灰とは、通常f−CaOと呼ばれるものである。
本発明で云うカルシウムアルミノフェライトとは、4CaO・Al・Fe(CAFと略記)や6CaO・2Al・Fe(CFと略記)や6CaO・Al・Fe(CAFと略記)で示されるものである。
The heat-treated product of the present invention includes calcium aluminoferrite, free lime and anhydrous gypsum.
The free lime referred to in the present invention is usually called f-CaO.
In the present invention, calcium aluminoferrite refers to 4CaO · Al 2 O 3 · Fe 2 O 3 (abbreviated as C 4 AF), 6CaO · 2Al 2 O 3 · Fe 2 O 3 (abbreviated as C 6 A 2 F) or 6CaO · Al 2 O 3 · Fe 2 O 3 (abbreviated as C 6 AF).

本発明の熱処理物に含まれる各成分の含有量は、以下の範囲であることが好ましい。カルシウムアルミノフェライトの含有量は、CaO原料、Al原料、およびF
原料を混合したものを熱処理する場合、カルシウムアルミノフェライト遊離
石灰の合計100部中、カルシウムアルミノフェライトを30〜90部、遊離石灰を
10〜70部の割合で含有する熱処理物が好ましい。
また、CaO原料、Al原料、およびFe原料に、さらにCaSO原料
を配合する場合には、カルシウムアルミノフェライトの含有量は、カルシウムアルミノフェライト、遊離石灰、無水石膏の合計100部中、20〜60部が好ましく、30〜50部がより好ましい。遊離石灰の含有量は、20〜70部が好ましく、30〜60部がより好ましい。無水石膏の含有量は、遊離石灰、カルシウムアルミノフェライトおよび無水石膏の合計100部中、10部以下が好ましく、1〜9部がより好ましい。なお、無水石膏は、カルシウムアルミノフェライト、遊離石灰を含む熱処理物に混合しても良い。
It is preferable that content of each component contained in the heat processing thing of this invention is the following ranges. The content of calcium aluminoferrite is CaO raw material, Al 2 O 3 raw material, and F
For heating a mixture of e 2 O 3 raw material, a calcium aluminosilicate ferrite, in total 100 parts of free lime, 30 to 90 parts of calcium alumino ferrite, Cook containing free lime in a proportion of 10 to 70 parts of preferable.
Moreover, when CaSO 4 raw material is further blended with CaO raw material, Al 2 O 3 raw material and Fe 2 O 3 raw material, the content of calcium aluminoferrite is a total of 100 in total of calcium aluminoferrite, free lime and anhydrous gypsum. In a part, 20-60 parts are preferable and 30-50 parts are more preferable. 20-70 parts are preferable and, as for content of free lime, 30-60 parts are more preferable. The content of the anhydrite is preferably 10 parts or less, more preferably 1 to 9 parts, in the total 100 parts of free lime, calcium aluminoferrite and anhydrite. Anhydrite may be mixed with a heat-treated material containing calcium aluminoferrite and free lime.

また、本発明の熱処理物を炭酸ガスで処理し、熱処理物中に炭酸カルシウムを生成させることは塩害対策用混和材の性能を確保する上で好ましい。炭酸ガスによる処理温度は400〜700℃が好ましい。
炭酸カルシウムの含有量は、炭酸カルシウム、カルシウムアルミノフェライト、遊離石灰、および無水石膏の合計100部中、0.5〜10部であることが好ましく、1〜6部がより好ましい。前記範囲外では、塩害抑制性能の向上が見られない場合がある。
Further, it is preferable to treat the heat-treated product of the present invention with carbon dioxide gas to form calcium carbonate in the heat-treated product from the viewpoint of securing the performance of the additive for preventing salt damage. The treatment temperature with carbon dioxide gas is preferably 400 to 700 ° C.
The content of calcium carbonate is preferably 0.5 to 10 parts in 100 parts in total of calcium carbonate, calcium aluminoferrite, free lime, and anhydrous gypsum, and more preferably 1 to 6 parts. Outside the above range, improvement in salt damage control performance may not be observed.

上記各成分の含有量は、従来一般の分析方法で確認することができる。例えば、粉砕した試料を粉末X線回折装置にかけ、生成鉱物を確認するとともにデータをリートベルト法にて解析し、各成分を定量することができる。また、化学成分と粉末X線回折の同定結果に基づいて、各成分の量を計算によって求めることもできる。
炭酸カルシウムの含有量は、示差熱天秤(TG−DTA)や示差熱熱量測定(DSC)などによって、炭酸カルシウムの脱炭酸に伴う質量変化から定量することができる。
The content of each of the above components can be confirmed by a conventional general analysis method. For example, the crushed sample can be subjected to a powder X-ray diffractometer to confirm the formed mineral and analyze the data by Rietveld method to quantify each component. The amount of each component can also be determined by calculation based on the chemical component and the identification result of powder X-ray diffraction.
The content of calcium carbonate can be quantified from the mass change associated with the decarboxylation of calcium carbonate using a differential thermal balance (TG-DTA), a differential thermal calorimetry (DSC), or the like.

本発明の塩害対策用混和材の粉末度は、ブレーン比表面積で2500〜9000cm/gが好ましく、3500〜9000cm/gがより好ましい。2500cm/g未満では、塩化物イオンの浸透抑制効果が不十分になる可能性や、初期強度の増進が不十分の場合や長期に亘って後膨張して強度が低下する場合がある。また、9000cm/gを超えるとコンクリートの流動性が低下するとともに、塩害抑制性能が不十分となる場合がある。
本発明の塩害対策用混和材の使用量は、コンクリート中のセメントと塩害対策用混和材の合計に対して、カルシウムアルミノフェライト量が10〜20%となるようにコンクリートに配合することが好ましい。
2500-9000 cm < 2 > / g is preferable at a brane specific surface area, and, as for the fineness of the admixture for salt damage measures of this invention, 3500-9000 cm < 2 > / g is more preferable. If it is less than 2500 cm 2 / g, the chloride ion permeation inhibition effect may be insufficient, or the increase in initial strength may be insufficient or the strength may decrease due to post expansion over a long period of time. When it exceeds 9000 cm 2 / g, the fluidity of the concrete may be lowered and the salt damage control performance may be insufficient.
The amount of the additive for preventing salt damage of the present invention is preferably blended in the concrete so that the amount of calcium aluminoferrite is 10 to 20% of the total of the cement in the concrete and the additive for preventing salt damage.

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、および中庸熱などの各種ポルトランドセメント、これらセメントに対して、高炉スラグ、フライアッシュ、およびシリカからなる群から選ばれる少なくとも1種を混合した各種混合セメント、ならびに石灰石粉末を混合したフィラーセメントなどが挙げられる。   As the cement used in the present invention, various portland cements such as normal, early strong, ultra early strong, low heat, and moderate heat, for these cements, at least one selected from the group consisting of blast furnace slag, fly ash and silica Examples include various mixed cements in which one kind is mixed, and filler cements in which limestone powder is mixed.

本発明では、砂、砂利の他、減水剤、高性能減水剤、AE減水剤、高性能AE減水剤、流動化剤、消泡剤、増粘剤、防錆剤、防凍剤、収縮低減剤、高分子エマルジョン、凝結調整剤、セメント急硬材、ベントナイトなどの粘土鉱物、ゼオライトなどのイオン交換体、シリカ質微粉末、炭酸カルシウム、水酸化カルシウム、石膏、ケイ酸カルシウム、鋼繊維などを併用することが可能である。有機系材料としては、ビニロン繊維、アクリル繊維、炭素繊維などの繊維状物質などが挙げられる。   In the present invention, sand, gravel, water reducing agent, high performance water reducing agent, AE water reducing agent, high performance AE water reducing agent, fluidizing agent, antifoamer, thickener, rust inhibitor, antifreeze agent, shrinkage reducing agent , Polymer emulsion, setting modifier, cement quick-hardening material, clay mineral such as bentonite, ion exchanger such as zeolite, siliceous fine powder, calcium carbonate, calcium hydroxide, gypsum, calcium silicate, steel fiber etc. It is possible. Examples of the organic material include fibrous materials such as vinylon fiber, acrylic fiber and carbon fiber.

以下、実施例および比較例により本発明を具体的に説明するが、本発明はこれらに限定されないことはもちろんである。   Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples, but it goes without saying that the present invention is not limited thereto.

「実験例1」
CaO原料、Al原料、およびFe原料、あるいは、CaO原料、Al原料、Fe原料およびCaSO原料を表1、2に記載するような所定の鉱物組成となるように混合した。この混合物を、電気炉を用いて1350℃で0.5時間熱処理し、得られた熱処理物をボールミルでブレーン比表面積3,500cm/gに粉砕し、塩害対策用混和材とした。
なお、遊離石灰(f−CaO)50部、カルシウムアルミノフェライト(CAF)40部、無水石膏(CaSO)10部の熱処理物について、炭酸ガス雰囲気下、600℃で処理を行い、処理時間を変えて、炭酸カルシウム(CaCO)含有量の異なる塩害対策用混和材を調製した。
次に、セメント450g、標準砂1350g、水225gを基準配合とし、表1、2に示すように塩害対策用混和材の種類とセメントに対する使用量を変えて、モルタルの膨張率、圧縮強さ、塩分浸透深さ、および曲げひび割れ発生強度比を評価した。塩害対策用混和材は、セメントに内割で配合した。
なお、遊離石灰(f−CaO)とカルシウムアルミノフェライト(CAF)を含む熱処理物に無水石膏(ブレーン比表面積5000cm/g、市販品)を添加した場合や、遊離石灰(f−CaO)とカルシウムアルミノフェライト(CAF)をそれぞれ純合成して、ブレーン比表面積3,500cm/gに粉砕して混合したものや、市販膨張材に純合成したカルシウムアルミノフェライト(CAF)を添加したものも評価した。
"Experimental Example 1"
Predetermined mineral compositions as described in Tables 1 and 2 for CaO raw material, Al 2 O 3 raw material, Fe 2 O 3 raw material, or CaO raw material, Al 2 O 3 raw material, Fe 2 O 3 raw material and CaSO 4 raw material It mixed so that it might become. The mixture was heat-treated at 1350 ° C. for 0.5 hour using an electric furnace, and the obtained heat-treated material was ground by a ball mill to a brane specific surface area of 3,500 cm 2 / g to obtain a salt damage countermeasure additive.
The heat treatment of 50 parts of free lime (f-CaO), 40 parts of calcium aluminoferrite (C 4 AF), and 10 parts of anhydrous gypsum (CaSO 4 ) is treated at 600 ° C. in a carbon dioxide gas atmosphere, and the treatment time is Were changed to prepare a salt damage additive having different calcium carbonate (CaCO 3 ) content.
Next, using 450 g of cement, 1350 g of standard sand and 225 g of water as a standard composition, the type of admixture for preventing salt damage and the amount used for cement are changed as shown in Tables 1 and 2, mortar expansion ratio, compressive strength, The salt penetration depth and bending crack initiation strength ratio were evaluated. The salt damage additive was incorporated into the cement in an internally split manner.
When anhydrous gypsum (Brene specific surface area: 5000 cm 2 / g, commercial product) is added to a heat-treated material containing free lime (f-CaO) and calcium aluminoferrite (C 4 AF), free lime (f-CaO) And calcium aluminoferrite (C 4 AF) were respectively pure synthesized and pulverized and mixed to a brane specific surface area of 3,500 cm 2 / g, or calcium aluminoferrite (C 4 AF) synthesized purely on a commercially available expansive material. What was added was also evaluated.

(使用材料)
CaO原料:炭酸カルシウム(石灰石微粉末)、100メッシュ、市販品
Al原料:ボーキサイト、90μm篩通過率100%、市販品
Fe原料:酸化鉄粉末、ブレーン比表面積3000cm/g、市販品
CaSO原料:ニ水石膏、ブレーン比表面積5000cm/g、市販品
セメント:普通ポルトランドセメント、市販品、密度3.16g/cm
市販膨張材:f−CaO50部、3CaO・3Al、CaSO12部、CaSO30部、エトリンガイト・石灰複合型膨張材、電気化学工業社製
砂:JIS標準砂
水:水道水
(Material used)
CaO raw material: calcium carbonate (fine limestone powder), 100 mesh, commercially available Al 2 O 3 raw material: bauxite, 90 μm sieve passing rate 100%, commercially available Fe 2 O 3 raw material: iron oxide powder, brane specific surface area 3000 cm 2 / g Commercially available product CaSO 4 Raw material: Dihydrated gypsum, Blaine specific surface area 5000 cm 2 / g, Commercially available product cement: Ordinary portland cement, commercially available product, density 3.16 g / cm 3
Commercially available expandable material: f-CaO50 parts, 3CaO · 3Al 2 O 3, CaSO 4 12 parts, CaSO 4 30 parts of ettringite-lime composite expanding material, manufactured by Denki Kagaku Kogyo KK sand: JIS standard sand Water: Tap water

(試験方法)
膨張率および圧縮強さ:JIS A 6202付属書1に準拠した。
塩分浸透深さ:材齢1日で脱型した40mm×40mm×160mmのモルタル試験体を材齢28日まで20℃水中で養生し、その後、疑似海水にモルタルを20℃環境下で浸漬した。浸漬3か月後にモルタル試験体を取り出し、モルタル断面に硝酸銀水溶液を吹きかけて、塩分浸透深さを測定した。測定は8か所測定し、平均値を求めた。
曲げひび割れ発生強度比:膨張率測定で用いた一軸拘束試験体を材齢28日まで20℃水中で養生した後、その後、疑似海水にモルタルを20℃環境下で浸漬した。浸漬3か月後にモルタル試験体を取り出し、端板を取り外した後、曲げ試験を実施した。ひび割れ発生時の荷重を計測し、塩害対策混和材を混和しない試験体との強度比を算出した。
(Test method)
Expansion coefficient and compressive strength: in accordance with JIS A 6202 Annex 1.
Salinity penetration depth: A 40 mm × 40 mm × 160 mm mortar specimen demolded at 1 day of age was aged in water at 20 ° C. until age 28 days, and then the mortar was immersed in simulated seawater under a 20 ° C. environment. Three months after immersion, the mortar specimen was taken out, and a silver nitrate aqueous solution was sprayed on the mortar cross section to measure the salt penetration depth. The measurement was performed at eight points, and the average value was obtained.
Flexural Crack Initiation Strength Ratio: The uniaxially restrained test body used in the measurement of expansion rate was cured in water at 20 ° C. until the age of 28 days, and then the mortar was immersed in simulated seawater under a 20 ° C. environment. Three months after immersion, the mortar specimen was taken out, and after removing the end plate, a bending test was performed. The load at the time of crack occurrence was measured, and the strength ratio to the test body not mixed with the salt damage countermeasure admixture was calculated.

Figure 0006509586
Figure 0006509586

Figure 0006509586
Figure 0006509586

表1、2より、本発明について以下のことが分かる。
(1)カルシウムアルミノフェライト含有量が高くなるにしたがって塩分浸透が抑制される。(2)熱処理物に無水石膏を共存させると膨張性能が向上するため、無水石膏の含有量を調整することによって、塩分浸透の抑制効果と膨張性能が両立することが可能となる。(3)熱処理物に炭酸カルシウムを生成させることによって、膨張率が向上する。(4)塩害対策混和材を混和しない試験体に比べて、曲げひび割れ発生強度比が高くなり、塩分が浸透してもひび割れ抵抗性に優れる。
From Tables 1 and 2, the following can be found for the present invention.
(1) Salt penetration is suppressed as the calcium aluminoferrite content increases. (2) When anhydrite is allowed to coexist in the heat-treated product, the expansion performance is improved. Therefore, by adjusting the content of the anhydrite, it is possible to achieve both the salt penetration permeation suppressing effect and the expansion performance. (3) The expansion coefficient is improved by generating calcium carbonate in the heat-treated product. (4) Measures against salt damage The bending crack occurrence strength ratio is higher than that of the test body in which the admixture is not mixed, and the crack resistance is excellent even if salt penetrates.

本発明により、塩化物を含む凍結防止材を散布しても鉄筋コンクリートの膨張率が高く塩害によるひび割れ発生を防止することが可能となることから、土木分野などで広範に適用できる。   According to the present invention, even if the antifreeze material containing chloride is dispersed, the expansion rate of reinforced concrete is high and it is possible to prevent the occurrence of cracking due to salt damage, so it can be widely applied in the civil engineering field and the like.

Claims (5)

CaO原料、Al23原料、およびFe23原料を混合したものを熱処理して得られ、カルシウムアルミノフェライト、および遊離石灰の合計100質量部中、カルシウムアルミノフェライトを30〜90質量部、遊離石灰を10〜70質量部の割合で含有する熱処理物を粉砕してなる塩害対策用混和材。 Obtained by heat treating a mixture of a CaO raw material, an Al 2 O 3 raw material, and an Fe 2 O 3 raw material, 30 to 90 parts by mass of calcium aluminoferrite in a total of 100 parts by mass of calcium aluminoferrite and free lime Admixture for salt damage prevention formed by grinding a heat-treated product containing free lime in a proportion of 10 to 70 parts by mass. CaO原料、Al23原料、およびFe23原料に、さらにCaSO4原料を混合したものを熱処理して得られ、カルシウムアルミノフェライト、遊離石灰、および無水石膏の合計100質量部中、カルシウムアルミノフェライトを10〜90質量部、遊離石灰を20〜70質量部、無水石膏を10質量部以下の割合で含有する熱処理物を粉砕してなる塩害対策用混和材。 CaO material, Al 2 O 3 raw material, and Fe in 2 O 3 raw material, further CaSO 4 obtained by Netsusho sense what raw material has been mixed, calcium alumino ferrite, free lime, and the sum of anhydrite 100 parts by in An additive for preventing salt damage which is obtained by grinding a heat-treated material containing 10 to 90 parts by mass of calcium aluminoferrite, 20 to 70 parts by mass of free lime, and 10 parts by mass or less of anhydrous gypsum. 熱処理物を炭酸化処理してなる請求項1または2記載の塩害対策用混和材。 The additive for salt damage prevention according to claim 1 or 2, wherein the heat-treated material is subjected to carbonation treatment. 請求項1〜3のいずれか1項記載の塩害対策用混和材をコンクリートに配合してなる鉄筋コンクリートの塩害対策方法。 The salt damage countermeasure method of the reinforced concrete formed by mix | blending the admixture for salt damage countermeasure of any one of Claims 1-3 with concrete. 塩害対策用混和材をコンクリート中のセメントに対してカルシウムアルミノフェライト含有量が10〜20質量%となるようにコンクリートに配合してなる請求項4に記載の鉄筋コンクリートの塩害対策方法。 5. The method for preventing salt damage to reinforced concrete according to claim 4, wherein the additive for preventing salt damage is mixed with concrete so that the calcium aluminoferrite content is 10 to 20% by mass with respect to cement in the concrete.
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