JPH0352421B2 - - Google Patents
Info
- Publication number
- JPH0352421B2 JPH0352421B2 JP4211382A JP4211382A JPH0352421B2 JP H0352421 B2 JPH0352421 B2 JP H0352421B2 JP 4211382 A JP4211382 A JP 4211382A JP 4211382 A JP4211382 A JP 4211382A JP H0352421 B2 JPH0352421 B2 JP H0352421B2
- Authority
- JP
- Japan
- Prior art keywords
- concrete
- reinforced concrete
- amount
- weight
- blast furnace
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000004567 concrete Substances 0.000 claims description 27
- 239000000463 material Substances 0.000 claims description 24
- 239000011150 reinforced concrete Substances 0.000 claims description 24
- 239000011230 binding agent Substances 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 12
- 239000002893 slag Substances 0.000 claims description 12
- 238000005260 corrosion Methods 0.000 claims description 11
- 230000007797 corrosion Effects 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 11
- 150000001875 compounds Chemical class 0.000 claims description 10
- 239000000126 substance Substances 0.000 claims description 9
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims description 8
- 239000004570 mortar (masonry) Substances 0.000 claims description 8
- 239000000843 powder Substances 0.000 claims description 7
- 239000011398 Portland cement Substances 0.000 claims description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 10
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 10
- 229910000831 Steel Inorganic materials 0.000 description 9
- 239000013535 sea water Substances 0.000 description 9
- 239000010959 steel Substances 0.000 description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- 230000003014 reinforcing effect Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000003795 chemical substances by application Substances 0.000 description 6
- 239000004576 sand Substances 0.000 description 6
- 229910000029 sodium carbonate Inorganic materials 0.000 description 5
- 239000004568 cement Substances 0.000 description 4
- 239000000460 chlorine Substances 0.000 description 4
- 229910052801 chlorine Inorganic materials 0.000 description 4
- -1 chlorine ions Chemical class 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000003449 preventive effect Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000011074 autoclave method Methods 0.000 description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical class OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 3
- 150000001805 chlorine compounds Chemical class 0.000 description 3
- 238000006703 hydration reaction Methods 0.000 description 3
- 238000004898 kneading Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000004480 active ingredient Substances 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000009415 formwork Methods 0.000 description 2
- 230000036571 hydration Effects 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000004575 stone Substances 0.000 description 2
- AEQDJSLRWYMAQI-UHFFFAOYSA-N 2,3,9,10-tetramethoxy-6,8,13,13a-tetrahydro-5H-isoquinolino[2,1-b]isoquinoline Chemical compound C1CN2CC(C(=C(OC)C=C3)OC)=C3CC2C2=C1C=C(OC)C(OC)=C2 AEQDJSLRWYMAQI-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 241001274216 Naso Species 0.000 description 1
- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 241001455273 Tetrapoda Species 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000012751 acid resistant agent Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 239000002518 antifoaming agent Substances 0.000 description 1
- 239000007798 antifreeze agent Substances 0.000 description 1
- 150000001720 carbohydrates Chemical class 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- OEERIBPGRSLGEK-UHFFFAOYSA-N carbon dioxide;methanol Chemical compound OC.O=C=O OEERIBPGRSLGEK-UHFFFAOYSA-N 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000000176 sodium gluconate Substances 0.000 description 1
- 235000012207 sodium gluconate Nutrition 0.000 description 1
- 229940005574 sodium gluconate Drugs 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 125000001174 sulfone group Chemical group 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
- 238000004017 vitrification Methods 0.000 description 1
- 238000004078 waterproofing Methods 0.000 description 1
Landscapes
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
本発明は、鉄筋コンクリートの製法、詳しくは
塩化物等、鉄筋腐食の面で有害な物質を含有せざ
るを得ないコンクリート材料を用いる鉄筋コンク
リートの製法に関する。
なお、本発明でいう鉄筋コンクリートとは、鉄
筋を使用するコンクリート工事や各種の鉄筋コン
クリート製品を意味する。
従来、コンクリート材料として、骨材の枯渇に
より海砂を使用したり、コンクリートの初期強度
発現を促進させるためにCaCl2やFeCl3などを添
加したりなどして、鉄筋腐食の面で有害な塩化物
等を含有したコンクリート材料を用いて、工事や
鉄筋コンクリート製品を製造することが多くなつ
てきている。
しかしながら、このような鉄筋腐食の面で有害
な塩化物等を含有したコンクリート材料を用いる
ことは、コンクリート工事や鉄筋コンクリート製
品の長期安定性などの面から、極力抑えることが
要求されている。
一方、鉄筋の腐食を防止する方法として、亜硝
酸塩を有効成分とする防錆剤を添加することが提
案されている（例えば、特開昭54−50526号公
報）。
しかしながら、亜硝酸塩を有効成分とする防錆
剤を使用する方法では、強度が低下したり、十分
な防錆効果が得られないなどの課題があつた。
本発明者らは、鉄筋腐食の面で有害な塩化物等
を含有したコンクリート材料を用いた鉄筋コンク
リートの製法において、鉄筋の防錆効果を高める
ために種々検討した結果、コンクリート材料の結
合材として、特定の材料を使用し、しかも、その
硬化物中のCa（OH）2生成量が少なくするものを
使用すれば、前述の課題が解決できる知見を得て
本発明を完成するに至つた。
即ち、本発明は、鉄筋腐食の面で有害な物質を
含有する、結合材以外のコンクリート材料と、結
合材とを混合した鉄筋コンクリートの製法におい
て、結合材としてポルトランドセメントとポゾラ
ン物質、又は高炉水砕スラグ粉末とアルカリ性化
合物からなり、鉄筋コンクリート硬化後のCa
（OH）2生成量が、硬化物中のモルタル分に対し
て、2.0重量％以下となるようなCaO含有物を用
いることを特徴とする鉄筋コンクリートの製法で
ある。
以下、詳しく本発明について説明する。
コンクリート材料としては、通常、普通ポルト
ランドセメントなどに代表される結合材、細骨材
（砂）、粗骨材（砂利）、AE剤や減水剤などの混和
剤、及び水等が使用される。
また、鉄筋腐食の面で有害な物質としては、海
水、海砂、及び一部の混和剤に含有されている塩
素イオン等をいう。
本発明に係る結合材とは、ポルトランドセメン
トとポゾラン物質、又は高炉水枠スラグ粉末とア
ルカリ性化合物のCaO含有物であり、コンクリー
ト硬化後のCa（OH）2生成量が、該硬化物中のモ
ルタル分の2.0重量％以下となるCaO含有物であ
る。
このうち、特に、高炉水砕スラグ粉末とアルカ
リ性化合物は、硬化後Ca（OH）2が生成しないの
で好ましい。
ここで、ポゾラン物質とは、ポゾラン反応を引
き起こすもので、具体的には、活性シリカやフラ
イアツシユなどが挙げられる。
高炉水砕スラグとは、銑鉄製造の際、高炉で発
生する、鉄鉱石中の不純物を主成分とするもの
で、水で急冷して得られるものである。
高炉水砕スラグの粉末度は、ブレーン比表面積
で3000cm2／ｇ以上が好ましく、そのガラス化率は
90％以上、塩基度（CaO＋MgO＋Al2O3）／
SiO2は1.5以上が好ましい。
アルカリ性化合物とは、高炉水砕スラグ粉末の
水和活性を高め、速やかに所要強度を発現させる
ために必要なものである。
アルカリ性化合物としては、アルカリ金属の水
酸化物、炭酸塩、及び炭酸水素塩等であり、防錆
効果、強度増進、さらには、入手の容易さを考慮
して、水酸化ナトリウム単独又は水酸化ナトリウ
ムと炭酸ナトリウムの併用が特に好ましい。
本発明では、硬化後のCa（OH）2生成量を極力
抑止し、炭酸作用によつて中性化されにくく、そ
のために、塩素イオンの浸透を抑え、かつ、それ
が拡散しないような能力のある鉄筋コンクリート
を製造し、それによつて、鉄筋の防錆効果の大な
る鉄筋コンクリートとすることを基本としている
ものである。
アルカリ性化合物として、水酸化ナトリウム単
独又は水酸化ナトリウムと炭酸ナトリウムの併用
が特に好ましい理由は、水酸化ナトリウムを添加
すれば、炭酸ガスと反応しても炭酸ナトリウムと
なつてアルカリ性を保つため、鉄筋コンクリート
のPHにはほとんど影響しないためと考えられる。
アルカリ性化合物の使用量は、少なすぎてはそ
の効果は少なく、多すぎると水和反応に悪影響を
およぼす恐れがある。そのため、高炉水砕スラグ
粉末100重量部に対して、0.5〜15重量部が好まし
く、８〜12重量部がより好ましい。
本発明において使用する結合材として、ポルト
ランドセメントとポゾラン物質、又は高炉水砕ス
ラグ粉末とアルカリ性化合物から、鉄筋コンクリ
ート硬化後のCa（OH）2生成量が、硬化物中のモ
ルタル分に対して、2.0重量％以下となるような
CaO含有物を用いた理由は次の通りと考えられ
る。
即ち、Ca（OH）2は、空気中の炭酸がスと反応
してCaCO3となり、コンクリート中のPHを低下
させ、海砂や海水中の塩素イオンと反応して可溶
性塩を生じ、塩素イオンの浸透を促進させるなど
鉄筋の腐食に対し抵抗力がなくなるからである。
本発明において、そのCa（OH）2生成量が、コ
ンクリート硬化物中のモルタル分の2.0重量％以
下となる結合材を使用するものであり、1.0重量
％以下となる結合材を使用することが好ましい。
Ca（OH）2の定量は、コンクリート中のモルタ
ル部分を取り出し、これをドライアイス−メタノ
ール雰囲気による凍結乾操（Ｄ−dry）した後、
示差走査熱量計で測定して求めることができる。
本発明法で、さらに、一般のセメント減水剤を
使用することは、低水・セメント比のコンクリー
トが得られ、より緻密なコンクリート硬化物が得
られ、外部からの有害成分侵入の面で一層効果が
ある。
特に、分子内にスルホン基を有する化合物、オ
キシ有機酸塩、及び糖類等の一種又は二種以上を
使用することは好ましい。
また、AE剤、消泡剤、防水剤、防凍剤、耐酸
剤、及び防錆剤等の混和剤を併用することも差し
支えない。
本発明法によれば、海砂、海石、及び海水を用
いた鉄筋コンクリートの製造が容易にできること
が最も秀れた効果であり、遠心コンクリート製
品、ボツクスカルバート、護岸ブロツク、テトラ
ポツト、矢板、アーム柵渠、柵渠、Ｕ字溝、汚水
桝、及び桝ブロツク等の製造や現場工事に使用可
能である。また、無筋コンクリートにも同様に応
用することができる。
以下、実施例をあげてさらに詳しく説明する。
実施例 １
水・セメント比70％、単位セメント量280Kg／
m3、スランプ８〜10cmのコンクリート配合を用
い、結合材として、CaO64.2％の普通ポルトラン
ドセメントのみを使用したもの（配合物Ｉ）、粉
末度5000cm2／ｇでCaO41.5％の高炉水砕スラグ
100重量部、水酸化ナトリウム（NaOH）５重量
部、及び炭酸ナトリウム（Na2CO3）2.5重量部か
らなる混合物を使用し、この結合材に、さらに、
グルコン酸ナトリウム0.1重量部を配合したもの
（配合物）を用い、また、骨材として川砂と最
大骨材寸法15mmの砕石を、練り混ぜ水として水道
水又は人工海水を使用して鉄筋コンクリート供試
体を作成した。
人工海水は、一級試薬のNaClを24.5ｇ、
MgCl2・H2Oを111ｇ、NaSO4を41ｇ、CaCl2を
12ｇ、及びKClを７ｇ、約９の蒸留水に順次溶
かし、その後、全量を水で10とした。
混練するときは、これを水で３倍に希釈して使
用した。
作成した鉄筋コンクリート供試体を用いて、日
本工業規格（案）“塩分を含んだコンクリート中
における補強用棒鋼の促進腐食試験方法”に準じ
て鉄筋の腐食試験を行なつた。
鋼材は、JIS Ｇ 3108及びJIS Ｇ 3121に規定
する、直径13mm長さ150mmのみがき棒鋼SGD−３
を、表面研磨し、アセトンで脱脂したものを用い
た。
まず、第１図に示すような型枠を組み、これに
前述のコンクリートを打込んで翌日にその硬化体
の上面をモルタルでキヤツピングし、さらにコン
クリート打込み後２日目に硬化体の上下面を置き
換えてスペーサーを外し、同様にモルタルでキヤ
ツピングし、材令７日まで20℃で封かん養生して
鉄筋コンクリート供試体を作成した。
このようにして得られた鉄筋コンクリート供試
体を、乾湿繰返し方法とオートクレーブ方法とに
より促進試験を行なつた後、供試体中の鋼材が載
荷方向に並ぶようにして割裂載荷を行い、鋼材を
とり出し直ちに発錆面積を測定した。
発錆面積の測定は、鋼材の長さ方向の中心から
５cmづつ計10cmの部分の鋼材、透明なシートをあ
て、鋼材上の明らかに発錆している部分を忠実に
写しとり発錆面積とした。その後、写しとつた部
分の面積の総合計を用いて、下式により発錆面積
率を求めた。
なお、単色で均一な薄い錆は発錆部分としなか
つた。
発錆面積率（％）＝発錆面積／測定面積×100
ここで、乾湿繰返し方法とは、60〜70℃、90％
RH以上の湿潤期間３日間、10〜15℃、70％RH
以下の乾燥期間４日間を１サイクルとして、20サ
イクル行つたものである。
また、オートクレーブ方法とは、１時間に約80
℃以下の速度で180℃まで昇温し、この温度で８
時間保持した後、上昇時よりもゆるやかな速度で
室温まで降下させたものである。
材令７日まで20℃で封かん養生した直後のコン
クリート硬化物中に生成しているCa（OH）2量を
示差走査熱量計で定量した。
鋼材を用いない供試体については、発錆面積測
定時の圧縮強度をｎ＝４で測定した。結果の平均
値を第１表に示す。
The present invention relates to a method for manufacturing reinforced concrete, and more particularly, to a method for manufacturing reinforced concrete using concrete materials that must contain substances harmful to reinforcing steel corrosion, such as chlorides. Note that the term "reinforced concrete" as used in the present invention means concrete work using reinforcing bars and various reinforced concrete products. Conventionally, sea sand has been used as a concrete material due to depletion of aggregate, and CaCl 2 and FeCl 3 have been added to promote the initial strength development of concrete. Construction work and reinforced concrete products are increasingly being manufactured using concrete materials containing substances. However, from the standpoint of concrete work and long-term stability of reinforced concrete products, it is required to minimize the use of concrete materials containing chlorides, etc., which are harmful to reinforcing steel corrosion. On the other hand, as a method of preventing corrosion of reinforcing bars, it has been proposed to add a rust preventive agent containing nitrite as an active ingredient (for example, Japanese Patent Laid-Open No. 54-50526). However, the method of using a rust preventive agent containing nitrite as an active ingredient has had problems such as a decrease in strength and an inability to obtain a sufficient rust preventive effect. The present inventors have conducted various studies to improve the rust prevention effect of reinforcing bars in the manufacturing method of reinforced concrete using concrete materials containing chlorides, etc., which are harmful to reinforcing steel corrosion. As a result, as a binding material for concrete materials, The present invention has been completed based on the knowledge that the above-mentioned problems can be solved by using a specific material that reduces the amount of Ca(OH) 2 produced in the cured product. That is, the present invention provides a method for producing reinforced concrete in which a binder is mixed with a concrete material other than a binder that contains substances harmful to reinforcing steel corrosion. Consisting of slag powder and alkaline compounds, Ca after hardening of reinforced concrete
This is a method for manufacturing reinforced concrete characterized by using a CaO-containing material such that the amount of (OH) 2 produced is 2.0% by weight or less based on the mortar content in the cured product. The present invention will be explained in detail below. Concrete materials typically include a binder such as ordinary Portland cement, fine aggregate (sand), coarse aggregate (gravel), admixtures such as AE agents and water reducers, and water. Substances harmful to reinforcing steel corrosion include seawater, sea sand, and chlorine ions contained in some admixtures. The binder according to the present invention is a CaO-containing material of Portland cement and a pozzolanic substance, or blast furnace water frame slag powder and an alkaline compound, and the amount of Ca(OH) 2 produced after concrete hardening is determined by the mortar in the hardened material. The content of CaO is 2.0% by weight or less. Among these, granulated blast furnace slag powder and alkaline compounds are particularly preferred since Ca(OH) 2 is not generated after hardening. Here, the pozzolan substance is something that causes a pozzolan reaction, and specifically includes activated silica and fly ash. Granulated blast furnace slag is mainly composed of impurities in iron ore generated in the blast furnace during the production of pig iron, and is obtained by quenching with water. The fineness of the granulated blast furnace slag is preferably 3000 cm 2 /g or more in Blaine specific surface area, and the vitrification rate is
90% or more, basicity (CaO + MgO + Al 2 O 3 ) /
SiO 2 is preferably 1.5 or more. The alkaline compound is necessary for increasing the hydration activity of the granulated blast furnace slag powder and quickly developing the required strength. Examples of alkaline compounds include hydroxides, carbonates, and hydrogen carbonates of alkali metals, and sodium hydroxide alone or sodium hydroxide is used in consideration of rust prevention effects, strength enhancement, and easy availability. A combination of sodium carbonate and sodium carbonate is particularly preferred. In the present invention, the amount of Ca(OH) 2 generated after curing is suppressed to the utmost, making it difficult to be neutralized by carbonic acid action. Therefore, the penetration of chlorine ions is suppressed, and the ability to prevent them from diffusing is suppressed. The basic idea is to manufacture a certain type of reinforced concrete, thereby making it a reinforced concrete that has a great rust-preventing effect on reinforcing bars. The reason why it is particularly preferable to use sodium hydroxide alone or a combination of sodium hydroxide and sodium carbonate as an alkaline compound is that when sodium hydroxide is added, even if it reacts with carbon dioxide, it becomes sodium carbonate and maintains its alkalinity. This is thought to be because it has almost no effect on pH. If the amount of the alkaline compound used is too small, the effect will be small, and if it is too large, it may adversely affect the hydration reaction. Therefore, it is preferably 0.5 to 15 parts by weight, more preferably 8 to 12 parts by weight, per 100 parts by weight of granulated blast furnace slag powder. As the binder used in the present invention, from portland cement and pozzolanic substances, or granulated blast furnace slag powder and alkaline compounds, the amount of Ca(OH) 2 produced after hardening of reinforced concrete is 2.0% relative to the mortar content in the hardened material. % by weight or less
The reason for using a CaO-containing material is considered to be as follows. In other words, Ca(OH) 2 reacts with carbonic acid in the air to become CaCO 3 , which lowers the PH in concrete, and reacts with chlorine ions in sea sand and seawater to produce soluble salts, causing chlorine ions to form. This is because the reinforcing steel becomes less resistant to corrosion, such as by promoting the penetration of steel. In the present invention, a binder whose Ca(OH) 2 generation amount is 2.0% by weight or less of the mortar content in the cured concrete product is used, and it is possible to use a binder whose generation amount is 1.0% by weight or less. preferable. To quantify Ca(OH) 2 , take out the mortar part from the concrete, freeze-dry it (D-dry) in a dry ice-methanol atmosphere, and then
It can be determined by measuring with a differential scanning calorimeter. In addition, using a general cement water reducing agent in the method of the present invention allows concrete with a low water/cement ratio to be obtained, a denser concrete hardened product, and is more effective in preventing harmful components from entering from outside. There is. In particular, it is preferable to use one or more of compounds having a sulfone group in the molecule, oxyorganic acid salts, and saccharides. Further, admixtures such as AE agents, antifoaming agents, waterproofing agents, antifreeze agents, acid-resistant agents, and rust preventive agents may be used in combination. According to the method of the present invention, the most outstanding effect is that reinforced concrete can be easily manufactured using sea sand, sea stone, and sea water, and it can be used for centrifugal concrete products, box culverts, seawall blocks, tetrapods, sheet piles, and arm fences. It can be used for manufacturing and on-site construction of culverts, fence culverts, U-shaped ditches, sewage basins, basin blocks, etc. Moreover, it can be similarly applied to unreinforced concrete. Hereinafter, the present invention will be explained in more detail with reference to examples. Example 1 Water/cement ratio 70%, unit cement amount 280Kg/
m 3 , using a concrete mix with a slump of 8 to 10 cm, using only ordinary Portland cement with CaO 64.2% as a binder (mixture I), blast furnace water with a fineness of 5000 cm 2 /g and CaO 41.5%. crushed slag
Using a mixture consisting of 100 parts by weight, 5 parts by weight of sodium hydroxide (NaOH), and 2.5 parts by weight of sodium carbonate (Na 2 CO 3 ), this binder was further added with:
A reinforced concrete specimen was made using a mixture containing 0.1 part by weight of sodium gluconate, river sand and crushed stone with a maximum aggregate size of 15 mm as aggregates, and tap water or artificial seawater as mixing water. Created. Artificial seawater contains 24.5g of NaCl, a first-class reagent,
111 g of MgCl 2 H 2 O, 41 g of NaSO 4 , CaCl 2
12 g and 7 g of KCl were sequentially dissolved in about 9 parts of distilled water, and then the total volume was made up to 10 parts with water. When kneading, this was diluted three times with water and used. Using the prepared reinforced concrete specimens, we conducted a corrosion test on reinforcing bars in accordance with the Japanese Industrial Standards (draft) ``Test method for accelerated corrosion of reinforcing steel bars in salt-containing concrete''. The steel material is SGD-3, a drilled steel bar with a diameter of 13 mm and a length of 150 mm, as specified in JIS G 3108 and JIS G 3121.
The surface was polished and degreased with acetone. First, construct a formwork as shown in Figure 1, pour the concrete described above into it, cap the upper surface of the hardened material with mortar the next day, and then cap the upper and lower surfaces of the hardened material on the second day after pouring the concrete. After replacing it, the spacer was removed, capped with mortar in the same manner, and sealed and cured at 20°C until 7 days old to create a reinforced concrete specimen. The reinforced concrete specimen thus obtained was subjected to an accelerated test using a dry-wet cycle method and an autoclave method, and then split loading was performed so that the steel materials in the specimen were lined up in the loading direction, and the steel materials were taken out. The rusted area was immediately measured. To measure the rusted area, apply a transparent sheet to the steel at a distance of 5cm from the center of the length of the steel, a total of 10cm, and faithfully copy the clearly rusted areas on the steel to determine the rusted area. did. Thereafter, using the total area of the copied parts, the rusted area ratio was determined by the following formula. Note that thin, monochromatic, uniform rust was not treated as a rusted part. Rust area rate (%) = Rust area / Measurement area x 100 Here, the dry-wet cycle method means 60-70℃, 90%
Humidity period above RH for 3 days, 10-15℃, 70%RH
20 cycles were performed, with the following drying period of 4 days being one cycle. In addition, the autoclave method is about 800 ml per hour.
Raise the temperature to 180℃ at a rate below ℃, and at this temperature 8
After the temperature was maintained for a certain period of time, the temperature was lowered to room temperature at a slower rate than during the rise. The amount of Ca(OH) 2 generated in the hardened concrete was quantified using a differential scanning calorimeter immediately after the concrete was cured in a sealed container at 20℃ for up to 7 days. For specimens not using steel materials, the compressive strength was measured at n=4 when measuring the rusted area. The average values of the results are shown in Table 1.
【表】【table】
【表】
第１表から明らかな通り、実験No.１−５と実験
No.１−６の実施例は、人工海水でコンクリートを
作製しても、全く鉄筋を腐食させないことが示さ
れ、従つて、海砂を使用しても、また、海水にさ
らされる環境でも鉄筋の腐食は進行しないことは
明らかである。
実施例 ２
第２表に示す結合材を用い、実施例１と同様の
方法で鉄筋コンクリート供試体を作成し、オート
クレーブで促進試験を行つた。混練水は人工海水
を用いた。各硬化物中のCa（OH）2生成量と鉄筋
の発錆面積率とを第２表に併記する。[Table] As is clear from Table 1, Experiment No. 1-5 and Experiment
Example No. 1-6 shows that even if concrete is made with artificial seawater, the reinforcing bars will not corrode at all. Therefore, even if sea sand is used and the reinforcing bars are exposed to seawater, It is clear that corrosion does not progress. Example 2 Reinforced concrete specimens were prepared in the same manner as in Example 1 using the binding materials shown in Table 2, and accelerated tests were conducted in an autoclave. Artificial seawater was used as the kneading water. The amount of Ca(OH) 2 produced in each cured product and the rusted area ratio of the reinforcing bars are also listed in Table 2.
【表】【table】
【表】
参考例
Ca（OH）2の量と発錆状態の関係を検討するた
め、高炉水砕スラグ100重量部、NaOH5重量部、
及びNa2CO32.5重量部を用い、また、普通ポルト
ランドセメントを用い、混練水は人工海水とし、
さらに、Ca（OH）2を添加して、実施例１と同様
に行い、鉄筋コンクリート供試体を作成し、オー
トクレーブ方法で促進試験を行つた。
Ca（OH）2添加量と発錆面積率と関係を第２図
に示す。
第２図から明らかなように、高炉水砕スラグを
使用した系の水和硬化後のCa（OH）2生成量は少
なく、Ca（OH）2を１％添加しても発錆面積率が
０であり、５％添加しても小さいものであつた。[Table] Reference example In order to examine the relationship between the amount of Ca(OH) 2 and the rusting state, 100 parts by weight of granulated blast furnace slag, 5 parts by weight of NaOH,
and 2.5 parts by weight of Na 2 CO 3 , ordinary Portland cement was used, and the kneading water was artificial seawater.
Furthermore, Ca(OH) 2 was added and the same procedure as in Example 1 was carried out to prepare a reinforced concrete specimen, and an accelerated test was conducted using an autoclave method. Figure 2 shows the relationship between the amount of Ca(OH) 2 added and the rust area ratio. As is clear from Figure 2, the amount of Ca(OH) 2 produced after hydration hardening in the system using granulated blast furnace slag is small, and even when 1% Ca(OH) 2 is added, the rusting area rate remains low. 0, and even if it was added by 5%, it was small.
第１図は、鉄筋コンクリート供試体を製造する
際に用いた型枠であり、Ａは断面図、Ｂは平面図
である。第２図はCa（OH）2の添加量と発錆面積
率との関係を示す図である。
FIG. 1 shows a formwork used when manufacturing a reinforced concrete specimen, with A being a cross-sectional view and B being a plan view. FIG. 2 is a diagram showing the relationship between the amount of Ca(OH) 2 added and the rusting area ratio.
Claims (1)
材以外のコンクリート材料と、結合材とを混合し
た鉄筋コンクリートの製法において、結合材とし
てポルトランドセメントとポゾラン物質、又は高
炉水砕スラグ粉末とアルカリ性化合物からなり、
鉄筋コンクリート硬化後のCa（OH）2生成量が、
硬化物中のモルタル分に対して、2.0重量％以下
となるようなCaO含有物を用いることを特徴とす
る鉄筋コンクリートの製法。1. In the manufacturing method of reinforced concrete in which a binder is mixed with concrete materials other than binders that contain substances harmful to reinforcing steel corrosion, portland cement and pozzolanic substances, or granulated blast furnace slag powder and alkaline compounds are used as binders. Consisting of
The amount of Ca(OH) 2 generated after reinforced concrete hardens is
A method for manufacturing reinforced concrete, characterized by using a CaO-containing material in an amount of 2.0% by weight or less based on the mortar content in the cured product.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4211382A JPS58161957A (en) | 1982-03-17 | 1982-03-17 | Manufacture of ferroconcrete |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4211382A JPS58161957A (en) | 1982-03-17 | 1982-03-17 | Manufacture of ferroconcrete |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58161957A JPS58161957A (en) | 1983-09-26 |
| JPH0352421B2 true JPH0352421B2 (en) | 1991-08-09 |
Family
ID=12626895
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4211382A Granted JPS58161957A (en) | 1982-03-17 | 1982-03-17 | Manufacture of ferroconcrete |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58161957A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5259094B6 (en) * | 2007-02-08 | 2019-07-24 | Ｊｆｅスチール株式会社 | Hydrated hardened body excellent in neutralization resistance with rebar |
| CN101787734B (en) * | 2010-02-26 | 2011-08-17 | 哈尔滨工业大学深圳研究生院 | Sea sand concrete member of admixtures and method for preparing same |
| CN101793055B (en) * | 2010-03-12 | 2011-06-15 | 哈尔滨工业大学深圳研究生院 | Sea-sand concrete member and manufacturing method thereof |
-
1982
- 1982-03-17 JP JP4211382A patent/JPS58161957A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58161957A (en) | 1983-09-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Samimi et al. | Durability of self-compacting concrete containing pumice and zeolite against acid attack, carbonation and marine environment | |
| Bakharev et al. | Resistance of alkali-activated slag concrete to carbonation | |
| Hooton | Canadian use of ground granulated blast-furnace slag as a supplementary cementing material for enhanced performance of concrete | |
| Adam | Strength and durability properties of alkali activated slag and fly ash-based geopolymer concrete | |
| JP2003306359A (en) | Cement composition and hydrated hardened body | |
| Massazza | Properties and applications of natural pozzolanas | |
| Al-Tamimi et al. | Assessment of self-compacting concrete immersed in acidic solutions | |
| Krivenko et al. | Alkali-aggregate reaction in alkali-activated cement concretes | |
| JP2006182583A (en) | Mortar or concrete having compacted surface layer and its manufacturing method | |
| Harilal et al. | Binary blended fly ash concrete with improved chemical resistance in natural and industrial environments | |
| De Souza et al. | Development of a durability indicator to forecast the efficiency of preventive measures against external sulphate attack | |
| Kawamura et al. | Correlation between pore solution composition and alkali silica expansion in mortars containing various fly ashes and blastfurnace slags | |
| Ahmed et al. | Effect of Alkali Concentration on Physico-Chemical and Mechanical Properties of Slag Based Geopolymer Cement. | |
| KR100225343B1 (en) | A cement composition having high durability | |
| JPH0352421B2 (en) | ||
| KR0125466B1 (en) | Soil stabilizer and process thereof | |
| JPS61106449A (en) | Improvement for properties of cement mortar and concrete | |
| KR20040089995A (en) | The manufacturing method and composition of Restoration mortar with function of sulfuric acid resistance | |
| Hobbs et al. | Alkali-silica reaction in concrete | |
| JP2503226B2 (en) | Alkali aggregate reaction inhibitor | |
| Paul et al. | Workability and Strength Characteristics of Alkali-Activated Fly ASH/GGBS Concrete Activated with Neutral Grade NaSiO for Various Binder Contents and the Ratio of the Liquid/Binder | |
| Kurtis et al. | Analysis of durability of advanced cementitious materials for rigid pavement construction in California | |
| JP2004105783A (en) | Solidification material and solidification method for soil | |
| Trägårdh et al. | 4.3 Sulphate attack | |
| Kawamura et al. | Effect of sodium chloride and sodium hydroxide from the surrounding solution on alkali-silica reaction in mortars containing fly ash |