JPS6152116B2 - - Google Patents
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- Publication number
- JPS6152116B2 JPS6152116B2 JP251084A JP251084A JPS6152116B2 JP S6152116 B2 JPS6152116 B2 JP S6152116B2 JP 251084 A JP251084 A JP 251084A JP 251084 A JP251084 A JP 251084A JP S6152116 B2 JPS6152116 B2 JP S6152116B2
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- JP
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- Prior art keywords
- cement
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- hydration
- hardened
- Prior art date
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- 239000004568 cement Substances 0.000 claims description 93
- 238000000034 method Methods 0.000 claims description 50
- 238000006703 hydration reaction Methods 0.000 claims description 37
- 230000008569 process Effects 0.000 claims description 35
- 230000036571 hydration Effects 0.000 claims description 32
- 238000010304 firing Methods 0.000 claims description 25
- 238000000465 moulding Methods 0.000 claims description 17
- 229940043430 calcium compound Drugs 0.000 claims description 16
- 150000001674 calcium compounds Chemical class 0.000 claims description 16
- 239000002994 raw material Substances 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 238000004898 kneading Methods 0.000 claims description 7
- 239000000654 additive Substances 0.000 claims description 6
- 239000000919 ceramic Substances 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 6
- 230000008018 melting Effects 0.000 claims description 6
- 230000000996 additive effect Effects 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- 239000004927 clay Substances 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 239000012779 reinforcing material Substances 0.000 claims description 3
- 239000010433 feldspar Substances 0.000 claims description 2
- 239000003365 glass fiber Substances 0.000 claims description 2
- 229930195733 hydrocarbon Natural products 0.000 claims description 2
- 150000002430 hydrocarbons Chemical group 0.000 claims description 2
- 238000005979 thermal decomposition reaction Methods 0.000 claims description 2
- 239000000835 fiber Substances 0.000 claims 2
- 239000002184 metal Substances 0.000 claims 2
- 229910052751 metal Inorganic materials 0.000 claims 2
- 230000000391 smoking effect Effects 0.000 claims 2
- 238000000151 deposition Methods 0.000 claims 1
- 230000000887 hydrating effect Effects 0.000 claims 1
- 239000000047 product Substances 0.000 description 55
- 239000002245 particle Substances 0.000 description 16
- 238000005452 bending Methods 0.000 description 12
- 239000011575 calcium Substances 0.000 description 9
- 239000000203 mixture Substances 0.000 description 8
- 239000011398 Portland cement Substances 0.000 description 7
- 229910052573 porcelain Inorganic materials 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000002344 surface layer Substances 0.000 description 6
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 5
- 235000011941 Tilia x europaea Nutrition 0.000 description 5
- 239000004571 lime Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 4
- 239000002893 slag Substances 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 238000003958 fumigation Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 239000004575 stone Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000012615 aggregate Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 1
- 229910052601 baryte Inorganic materials 0.000 description 1
- 239000010428 baryte Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 235000010216 calcium carbonate Nutrition 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- BXKDSDJJOVIHMX-UHFFFAOYSA-N edrophonium chloride Chemical compound [Cl-].CC[N+](C)(C)C1=CC=CC(O)=C1 BXKDSDJJOVIHMX-UHFFFAOYSA-N 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 150000004677 hydrates Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 238000004154 testing of material Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Description
この発明は、セメントと骨材及び水とを混練し
てなるセメント混練物を所望の形状に成形した
後、水中または気中等でセメント粒子を水和反応
させることにより、硬化したセメント成形品を得
る方法の改良に関し、主原料としてのセメントと
骨材に、添加物としてのカルシウム化合物をCaO
に換算して、対セメント重量比で５％以下の僅少
量加えたものを、適量の水で十分混練してなるカ
ルシウム化合物添加セメント混練物を、所望の形
状に加圧成形し、この成形工程に続く水和硬化工
程を、時間的に先に行う予備的な水和硬化工程
と、時間的に後に行う本格的な水和硬化工程とに
区分して行うと共に、この予備的水和硬化工程と
本格的水和硬化工程との間に、予備的水和硬化工
程を経た中間製品を高温焼成する工程を組み込む
ことにより、従来のセメント成形品に比して一段
と機械的強度の優れたセメント成形品を得ること
ができるようにしたセメント製品の製造方法に関
する。
セメント硬化体は、これを450℃以上の高温で
加熱すると必らず、その機械的強度が著しく劣化
する。
例えば、ポルトランドセメント系のセメント硬
化体を450℃で加熱した場合は、珪酸石灰の水和
により生じたCa（OH）2がCaOとH2Oとに分解
し、このときセメント硬化体の内部に大きな収縮
変化が生じるため、セメント硬化体の機械的強
度、殊に圧縮強度が著しく劣化することが知られ
ている〔原田有・酒井享「耐熱コンクリートにつ
いて」（工業と製品No.50第119頁右欄）〕。
また、アルミナセメント系のセメント硬化体に
ついても、その化学的な理由は上記ポルトランド
セメントの場合と同一ではないが、やはり高温加
熱によつてその機械的強度が著しく劣化すること
が知られている〔若林明「アルミナセメント硬化
体の高温性状について」（窯業協会誌69(2)1961年
第28頁）〕。
従つて、従来はセメント成形品の強度向上のた
めに、セメント硬化体を高温焼成するなどという
ことは誰も考え及ばぬことであつた。
このような技術状況であつたから、粘土成形品
の製造に際して、粘土成形体の表面に美麗な色調
と光沢を与えるために広く行われている、いわゆ
る燻化処理も、セメント成形品に対しては、燻化
のために必要な高温加熱がセメント製品の強度を
劣化させるという理由によつて、実際には適用で
きないと考えられていた。
また、同様の理由により、セメント成形品の表
面を施釉仕上げするについても、種々の制約が存
在せざるを得なかつた。すなわち、セメント硬化
体の強度劣化が生じない450℃以下の温度範囲に
おいて十分に溶融可能な釉薬でないと、釉薬を融
着するために行う焼成によつて施釉セメント硬化
体自体が著しく機械的強度の乏しいものとならざ
るを得ないからである。そこで1974年（昭和49
年）日本特許出願公告第10530号の発明の如き、
低融点のりん酸系フリツト釉が開発されたが、こ
の特殊な釉薬は通常の高融点釉薬に比して、耐候
性においても耐薬品性においても劣るのみなら
ず、それ自体非常に高価であり、しかもこれを用
いた施釉セメント製品の表面は、美的観点から見
て余りよい出来ばえのものではないという欠点を
有していた。
この発明の発明者等は、先にセメント成形品の
製造工程中に敢えてセメント硬化体を高温で焼成
する工程を組み込み、その前後に予備的水和硬化
工程と本格的水和硬化工程を行うことにより、従
来のセメント製品に比して一段と機械的強度の優
れたセメント製品を製造する方法を提案した（特
願昭52−087196号）。この発明は、該提案方法の
原料であるセメント及び骨材に、更に添加物とし
てのカルシウム化合物をCaOに換算して対セメン
ト重量比で５％以下加えることにより、製品の機
械的強度を更に増強させ得るセメント製品製造法
の改良方法を提供することを目的とするものであ
る。
この発明はまた、表面に美麗で且つ光沢のある
炭素の薄膜が形成された、いわゆる燻化処理を施
したセメント製品を製造する方法を提供すること
を目的とするものである。
この発明の第三の目的は、表面に高融点の釉薬
を施した美麗な施釉セメント製品を製造する方法
を提供することである。
この発明のその他の目的は、以下の記述により
自ずと明らかになるであろう。
この発明は、予備的な水和硬化工程を経たセメ
ント硬化体を高温焼成することによる機械的強度
の劣化の程度は、焼成工程に引続く本格的な水和
硬化工程による機械的強度の増強に比して小さい
という事実の発見、すなわち成形工程の後に、予
備的水和硬化工程と本格的水和硬化工程とを設
け、その間に高温焼成工程を組み込む場合には、
セメント硬化体を高温焼成しない従来法によるセ
メント成形品よりも一段と機械的強度に優れたセ
メント成形品が得られるという発明者達の研究結
果に基礎をおくと共に、主原料としてのセメント
及び骨材に僅少量のカルシウム化合物を添加する
ときは、セメント製品の機械的強度の増強度が更
に優れたものになるという新らたな知見を応用し
たものである。すなわちこの発明は、セメントと
骨材を混合したものに、添加物としてのカルシウ
ム化合物をCaOに換算して対セメント重量比で５
％以下加してなる原料に水を加え、更に必要に応
じてガラス繊維などの補強材を加え、十分に混練
する原料混練工程と、この混練物を所望の形状に
成形する加圧成形工程と、この成形体を予備的に
水和硬化させる予備的水和硬化工程と、この予備
的工程により得られる硬化体を高温度で焼成する
焼成工程と、この焼成体を十分に水和硬化させる
本格的水和硬化工程とを、この順序で行うことを
特徴とするセメント製品の製造方法である。
上記の予備的工程を経た硬化体の焼成にあた
り、還元性の雰囲気中で燻化剤を燃焼させること
により、燻化剤中に含まれる炭化水素が熱分解す
ることによつて生じる微粒状炭素を予備的硬化体
の表面に沈着させるようにすると、この特別な焼
成工程によつて、その表面が光沢のある炭素薄膜
で美しく被覆されたいわゆる燻化物が、焼成品と
して得られる。
また上記の予備的工程を経た硬化体の焼成にあ
たり、予めこの予備的硬化体の表面に高融点の釉
薬を施しておくと、高温焼成の過程において、こ
の釉薬が予備的硬化体の表面に融着するので、美
麗で且つ光沢に富んだ施釉物が、焼成品として得
られる。
この発明によるセメント製品の機械的強度増大
のメカニズムは未だ十分に解明されてはいない
が、発明者達は多分次のようなメカニズムによる
ものであろうと考えている。すなわち、よく知ら
れているように、水和によるセメントの硬化反応
は、非常な長年月に亘つて進行する。或る研究に
よると、40μ以上の粗粒クリンカーは30年以上を
経過しても、なおその内部は元のクリンカーの
まゝであると言われている。またアンデレーグ
（Anderegg）及びヒユーベル（Hubbel）の両氏
の研究によると、粒径15〜30μのクリンカーを水
和させた場合、７日間の水和で、粒子表面からわ
ずかに1.5μの厚さしか水和反応が進行せず、28
日間の水和では3.5μの厚さ、90日間の水和でも
わずかに5.0μの厚さまでしか水和反応が進行し
なかつたと報告されている〔アンデレーク及びヒ
ユーベル アメリカ材料試験協会会誌1929、
（Anderegg and Hubbel：Proc.A.S.T.M.、
1929、）同コンクリート1930（Concrete、
1930）〕。このような事実に照らすと、セメント粒
子の水和反応は30〜100日間くらいのところで全
体の約1/2が進行し、それから数年の長期にわた
つて極めて徐々にその度を増して行くが、なお30
％以上の未水和部分を提内部に残存していると推
測される。
これに対し、本発明の方法によれば、予備的水
和硬化工程を経ることによつて表面から数μの厚
さまで水和反応が進行したセメント粒の、硬化し
た水和表層が、これに引続く高温焼成工程を経る
ことによつて毀損され、この硬化水和表層に生じ
た亀裂が、粒子内部の未水和部分と粒子外に存在
する水との接触通路として機能すると同時に、硬
化過程で遊離したCa（OH）2及び予め原料に添加
しておいたカルシウム化合物が高温焼成工程を経
ることによつてCaOになり、これが前記硬化水和
表層の亀裂からセメント粒子内に、水と共に侵入
する。その結果、最後の本格的水和硬化工程の過
程においては、焼成工程を間に介在させることな
く、予備的水和硬化工程をそのまゝ継続した場合
に比して、粒子表層からより深い粒子内奥部部分
をも水和させることができ、結課的には水和反応
の粒子内部への進行速度を増大させると共に、粒
子内へ浸入したCaOは吸湿によつてCa（OH）2に
なつて体積を膨張させるので、粒子内に存在した
空隙はそのほとんどが埋められ、更には空隙を充
填したCa（OH）2が炭酸化されるので、厚い硬化
表層を有すると同時に密かな組織が、比較的短時
間のうちに形成されるのであろうと考えられる。
この発明の発明者達は目下、上記仮説の検証に
努めているところであるが、この発明の予備的水
和硬化工程の期間を除く他のすべての条件を同一
とした場合、最終製品の機械的強度は、予備的水
和硬化工程の期間が長ければ長い程、大きくなる
という関係にあることを確認している。この事実
は上記仮説が妥当性を有することを裏付ける資料
となり得るであろう。
この発明を、その実施例に基づいて説明すると
次のとおりである。
実施例
普通ポルトランドセメント100重量部、信濃川
川砂200重量部、足立石灰２重量部、水60部の調
合物を10分間混練し、得られたセメント混練物を
500t油圧プレスにより、成形圧100Kgf/cm2、圧力
保持時間４分間の条件で加圧成形して水固形物比
0.1のセメント成形物を得る。このセメント成形
物を気中で１日養生して予備的に硬化させた後、
電気炉で２時間かけて850℃に昇温し、15分間の
間850℃の高温を保持した後、10時間かけて20℃
に降温することにより焼成した。20℃に冷却後、
60℃の湿潤蒸気養生を７日間行つてセメント製品
を得た。このセメント製品の曲げ強度を、スパン
45mm、荷重速度10mm/minに設定したテンシロン
で測定したところ、112.7Kg/fcm2であつた。足立
石灰を全く加えずに、同一条件で成形、予備的水
和、焼成及び本格的水和を行つたものの曲げ強度
は、81.8Kgf/cm2であつた。
本発明の出発原料の一つである「セメント」
は、ポルトランドセメント、アルミナセメントの
みならず、フライアツシユセメント、高炉スラグ
セメント、石灰＝スラグ系セメント等の混合セメ
ントを包含する概念であり、この語は種類の如何
を問わず水和反応により硬化を示すすべての物質
を指すものとして理解されなければならない。即
ち、本発明によるセメント製品の強度発現は、水
和物によるフアンデアワールズ力を高め、ケミカ
ルストレスを作用させて粒子間強度を向上させる
ものであるから、成分組成の異なるポルトランド
セメント以外のセメントについても適用し得るも
のであることは明らかである。また本発明の出発
原料の一つである「骨材」は、焼成工程における
高温焼成において急激な膨張や収縮を生じない、
温度＝体積変化の小さなものであることが必要で
ある。この要求を満たすものとしては、例えば重
晶石に代表される重量骨材、砂、砂利、砕石、ス
ラグ、陶器質シヤモツト、磁器質シヤモツト等の
普通骨材、並びに人工軽量骨材に代表される軽量
骨材等が挙げられる。就中、本発明の特色である
機械的強度の増大効果の観点から、特に推奨でき
るのは陶器質又は磁器質シヤモツトである。
本発明の重要な添加物である「カルシウム化合
物」は、焼成工程を経ることによつてCaOを生成
し、空隙部を埋めるものでありさえすればその種
類を問わない。主要なものとしてはCaCO3、
CaO、Ca（OH）2、CaCO3、MgCO3等がある。な
お、カルシウム化合物の添加量と製品の曲げ強度
との関係は、セメントの種類並びに予備的水和硬
化の方法及び日数の相違に応じて、すなわち予備
的水和硬化工程においてセメントから遊離する
Ca（OH）2の量に応じて多少変化するものである
が、一般的に言つて、カルシウム化合物をCaOに
換算して対セメント重量比で５％を越えて添加す
る場合には、無添加の場合より製品の曲げ強度が
低下するので、この添加量はCaOに換算して対セ
メント重量比で５％以下であることが必要であ
る。（後出の第１表参照のこと）。この限定は、従
来と同様に、添加されたCaOの吸湿崩塊による危
険を考慮したものであるが、しかし、セメント製
品へのカルシウム化合物の添加は、常に必ずしも
吸湿による崩塊につながるわけではなく、一定の
量以下の添加であれば、カルシウム化合物を全然
添加しない場合に比して却つてセメント製品の強
度を十分に向上させるものであるという新規な知
見にもとずいて、本発明では、カルシウム化合物
の添加量を前記の如く規定したのである。
次に本発明における加圧成形の成形圧は30Kgf/
cm2以上であることを要し、殊に50Kgf/cm2以上であ
ることが望ましい。この成形圧の圧力保持時間は
５分間以下で十分である。
また焼成工程における焼成温度は650〜950℃で
あることが望ましい。
ポルトランドセメント100重量部、磁器質シヤ
モツト200重量部からなる主原料に、CaCO3（足
立石灰）を０〜30重量部まで添加増量した数種類
のカルシウム添加原料を用い、これら原料に水60
重量部を加えて10分間混練して得られたセメント
混練物を、500トン油圧プレスにより、成形圧100
Kgf/cm2、圧力保持時間４分間の条件で加圧成形し
て水固形物比0.1のセメント成形物を得、これを
気中で１日養生した後、前記実施例と同一条件で
焼成及び本格的水和硬化させて製造した各種セメ
ント製品の曲げ強度を実測したところ、CaCO3
（足立石灰）の添加量と製品の曲げ強度との間に
は第１表に示す如き関係があつた。
This invention obtains a hardened cement molded product by molding a cement mixture made by kneading cement, aggregate, and water into a desired shape, and then subjecting the cement particles to a hydration reaction in water or air. Regarding the improvement of the method, calcium compounds were added as CaO to cement and aggregate as the main raw materials.
Calcium compound-added cement kneaded product obtained by sufficiently kneading a small amount of 5% or less in weight ratio to cement with an appropriate amount of water is pressure-molded into a desired shape, and this molding process The hydration curing process that follows is divided into a preliminary hydration curing process that is carried out earlier in terms of time, and a full-scale hydration curing process that is carried out later in terms of time, and this preliminary hydration and curing process. By incorporating a process of high-temperature firing of the intermediate product that has gone through the preliminary hydration hardening process between the final hydration hardening process and the full-scale hydration hardening process, we are able to create cement moldings with even greater mechanical strength than conventional cement molded products. The present invention relates to a method for manufacturing cement products that enables the production of cement products. When hardened cement is heated to a high temperature of 450°C or higher, its mechanical strength deteriorates significantly. For example, when a cement hardened body of Portland cement is heated at 450°C, Ca(OH) 2 generated by hydration of lime silicate decomposes into CaO and H 2 O, and at this time, inside the hardened cement body. It is known that the mechanical strength, especially the compressive strength, of hardened cement deteriorates significantly due to large shrinkage changes [Yu Harada and Akira Sakai, "About Heat-Resistant Concrete" (Industry and Products No. 50, p. 119) right column)]. Furthermore, it is known that the mechanical strength of alumina cement-based hardened cement deteriorates significantly when heated at high temperatures, although the chemical reasons for this are not the same as those for Portland cement. Akira Wakabayashi, “On the high-temperature properties of hardened alumina cement” (Journal of Ceramics Association 69(2), 1961, p. 28). Therefore, in the past, no one had thought of firing a hardened cement body at a high temperature in order to improve the strength of a cement molded product. Because of this technological situation, the so-called fumigation treatment, which is widely used to give beautiful color and gloss to the surface of clay molded products when manufacturing clay molded products, is not suitable for cement molded products. , was thought to be impractical because the high temperatures required for fumigation degraded the strength of cement products. Furthermore, for the same reason, various restrictions have inevitably been imposed on the glazing and finishing of the surface of cement molded products. In other words, unless the glaze is sufficiently meltable in the temperature range of 450°C or below, where no strength deterioration of the hardened cement product occurs, the glazed hardened cement product itself will significantly deteriorate in mechanical strength due to the firing performed to fuse the glaze. This is because it has no choice but to be scarce. So in 1974 (Showa 49)
) such as the invention of Japanese Patent Application Publication No. 10530,
A phosphoric acid-based frit glaze with a low melting point has been developed, but this special glaze is not only inferior in weather resistance and chemical resistance to ordinary high melting point glazes, but it is also very expensive. Moreover, the surface of glazed cement products using this method had the disadvantage that it was not very well made from an aesthetic point of view. The inventors of this invention intentionally incorporated a step of firing the hardened cement body at a high temperature into the manufacturing process of cement molded products, and performed a preliminary hydration hardening step and a full-scale hydration hardening step before and after that. proposed a method for manufacturing cement products with even greater mechanical strength than conventional cement products (Japanese Patent Application No. 1987-087196). This invention further enhances the mechanical strength of the product by adding a calcium compound as an additive to the cement and aggregate, which are the raw materials of the proposed method, at a weight ratio of 5% or less to the cement in terms of CaO. The purpose of this invention is to provide an improved method for manufacturing cement products. Another object of the present invention is to provide a method for producing a so-called smoked cement product, which has a beautiful and shiny carbon thin film formed on its surface. A third object of the present invention is to provide a method for manufacturing a beautiful glazed cement product whose surface is coated with a glaze having a high melting point. Other objects of the invention will become apparent from the following description. This invention aims to reduce the degree of deterioration in mechanical strength caused by high-temperature firing of a hardened cement body that has undergone a preliminary hydration hardening process, due to the increase in mechanical strength caused by the full-scale hydration hardening process that follows the firing process. In other words, when a preliminary hydration hardening process and a full-scale hydration hardening process are provided after the molding process, and a high-temperature firing process is incorporated between them,
Based on the inventors' research results that show that cement molded products can be obtained that have much better mechanical strength than cement molded products made using conventional methods that do not sinter the hardened cement body at high temperatures, This is an application of the new knowledge that when a small amount of calcium compound is added, the degree of mechanical strength enhancement of cement products becomes even more excellent. In other words, this invention adds a calcium compound as an additive to a mixture of cement and aggregate, calculated as CaO, at a weight ratio of 5 to cement.
A raw material kneading step in which water is added to the raw material obtained by adding % or less, further adding reinforcing material such as glass fiber as necessary, and thoroughly kneaded, and a pressure molding step in which this kneaded product is molded into a desired shape. , a preliminary hydration hardening step in which this molded body is preliminarily hydrated and hardened, a firing step in which the hardened body obtained in this preliminary step is fired at a high temperature, and a full-scale hydration hardening process in which this fired body is sufficiently hydrated and hardened. This method of manufacturing a cement product is characterized in that the steps of hydration and hardening are performed in this order. When firing the cured product that has gone through the above preliminary steps, by burning the fumigating agent in a reducing atmosphere, particulate carbon produced by thermal decomposition of the hydrocarbons contained in the fumigating agent is removed. When deposited on the surface of the pre-cured body, this special firing process yields a so-called smoked product whose surface is beautifully coated with a shiny carbon film. Furthermore, when firing the cured body that has gone through the above preliminary process, if a glaze with a high melting point is applied to the surface of the preliminary cured body in advance, this glaze will melt onto the surface of the preliminary cured body during the high temperature firing process. Because of this, beautiful and glossy glazed objects can be obtained as fired products. Although the mechanism by which the mechanical strength of cement products is increased by this invention has not yet been fully elucidated, the inventors believe that it is probably due to the following mechanism. That is, as is well known, the hardening reaction of cement due to hydration proceeds over many years. According to some research, it is said that even after more than 30 years, coarse clinker with a size of 40μ or more remains the same inside as the original clinker. Furthermore, according to research by Anderegg and Hubbel, when clinker with a particle size of 15 to 30 μm is hydrated, only a thickness of 1.5 μm reaches from the particle surface after 7 days of hydration. The sum reaction does not proceed, and 28
It is reported that the hydration reaction progressed to a thickness of 3.5μ after hydration for one day, and only 5.0μ after 90 days of hydration [Anderek and Hubel, Journal of the American Society for Testing and Materials 1929,
(Anderegg and Hubbel: Proc.ASTM,
1929, ) same concrete 1930 (Concrete,
1930)] In light of these facts, approximately 1/2 of the total hydration reaction of cement particles progresses in about 30 to 100 days, and then gradually increases in degree over a period of several years. , 30
It is estimated that more than % of the unhydrated portion remains within the hydration chamber. In contrast, according to the method of the present invention, the hardened hydrated surface layer of the cement grains, in which the hydration reaction has progressed to a thickness of several micrometers from the surface through the preliminary hydration hardening step, The cracks formed in the hardened and hydrated surface layer, which are damaged by the subsequent high-temperature firing process, function as contact passages between the unhydrated parts inside the particles and the water existing outside the particles, and at the same time, the hardening process Ca(OH) 2 liberated in the process and calcium compounds added to the raw material in advance become CaO through the high-temperature firing process, which enters into the cement particles through the cracks in the hardened and hydrated surface layer along with water. do. As a result, during the final full-scale hydration hardening process, the particles grow deeper from the particle surface layer than if the preliminary hydration hardening process was continued without intervening the firing process. It is possible to hydrate even the innermost part of the particle, ultimately increasing the rate of progress of the hydration reaction inside the particle, and CaO that has entered the particle becomes Ca(OH) 2 by moisture absorption. As the particles expand in volume, most of the voids that existed within the particles are filled, and the Ca(OH) 2 that filled the voids is carbonated, resulting in a thick hardened surface layer and a dense structure. , it is thought that they are formed within a relatively short period of time. The inventors of this invention are currently working to verify the above hypothesis. It has been confirmed that the strength increases as the period of the preliminary hydration curing process increases. This fact may serve as evidence to support the validity of the above hypothesis. The present invention will be explained based on examples as follows. Example A mixture of 100 parts by weight of ordinary Portland cement, 200 parts by weight of Shinano River sand, 2 parts by weight of Adachi lime, and 60 parts of water was kneaded for 10 minutes, and the resulting cement mixture was mixed.
Pressure molded using a 500t hydraulic press at a molding pressure of 100Kgf/cm 2 and a pressure holding time of 4 minutes to determine the water-solid ratio.
Obtain a cement molding of 0.1. After curing this cement molding in the air for one day to preliminarily harden it,
The temperature was raised to 850℃ over 2 hours in an electric furnace, maintained at a high temperature of 850℃ for 15 minutes, and then heated to 20℃ over 10 hours.
It was fired by lowering the temperature to . After cooling to 20℃,
A cement product was obtained by performing humid steam curing at 60°C for 7 days. The bending strength of this cement product is
When measured with Tensilon, which was set at 45 mm and a loading speed of 10 mm/min, it was 112.7 Kg/fcm 2 . The bending strength of the product which was subjected to molding, preliminary hydration, firing, and full-scale hydration under the same conditions without adding any Adachi lime was 81.8 Kgf/cm 2 . "Cement" which is one of the starting materials of the present invention
is a concept that encompasses not only Portland cement and alumina cement, but also mixed cements such as fly ash cement, blast furnace slag cement, and lime-slag cement. shall be understood as referring to all substances shown. In other words, the strength of the cement product according to the present invention is achieved by increasing the Juan der Waals force due to hydrates and improving the interparticle strength by applying chemical stress. It is clear that the same can also be applied. In addition, "aggregate", which is one of the starting materials of the present invention, does not undergo rapid expansion or contraction during high-temperature firing in the firing process.
It is necessary that the change in temperature = volume is small. Examples of materials that meet this requirement include heavy aggregates typified by barite, normal aggregates such as sand, gravel, crushed stone, slag, ceramic siyamots, porcelain siyamots, and artificial lightweight aggregates. Examples include lightweight aggregate. Among these, ceramic or porcelain ceramics are particularly recommended from the viewpoint of the effect of increasing mechanical strength, which is a feature of the present invention. The "calcium compound", which is an important additive in the present invention, can be of any type as long as it generates CaO through the calcination process and fills the voids. The main ones are CaCO3 ,
There are CaO, Ca(OH) 2 , CaCO 3 , MgCO 3 , etc. The relationship between the amount of calcium compound added and the bending strength of the product depends on the type of cement and the method and number of days of preliminary hydration hardening.
This will vary somewhat depending on the amount of Ca(OH) 2 , but generally speaking, if calcium compounds are added in an amount exceeding 5% by weight of cement in terms of CaO, no additives are required. Since the bending strength of the product is lower than in the case of CaO, the amount added needs to be 5% or less based on the weight of cement in terms of CaO. (See Table 1 below). This limitation, as in the past, takes into account the risk of hygroscopic agglomeration of added CaO; however, the addition of calcium compounds to cement products does not always lead to hygroscopic agglomeration. Based on the new finding that the addition of calcium compounds below a certain amount can sufficiently improve the strength of cement products compared to the case where no calcium compounds are added, the present invention provides the following: The amount of calcium compound added was defined as described above. Next, the molding pressure of pressure molding in the present invention is 30Kgf/
cm 2 or more, particularly preferably 50 Kgf/cm 2 or more. A pressure holding time of 5 minutes or less is sufficient for this molding pressure. Further, the firing temperature in the firing step is preferably 650 to 950°C. The main raw materials are 100 parts by weight of Portland cement and 200 parts by weight of porcelain shamots, and several types of calcium-added raw materials are added to increase the amount by adding 0 to 30 parts by weight of CaCO 3 (Adachi lime).
The cement mixture obtained by adding parts by weight and kneading for 10 minutes was heated to a molding pressure of 100 using a 500 ton hydraulic press.
Kgf/cm 2 and a pressure holding time of 4 minutes to obtain a cement molded product with a water-solid ratio of 0.1. After curing in air for 1 day, it was fired and molded under the same conditions as in the previous example. When we actually measured the bending strength of various cement products manufactured by full-scale hydration hardening, we found that CaCO 3
There was a relationship as shown in Table 1 between the amount of (Adachi lime) added and the bending strength of the product.
【表】
この第１表から明らかな如く、最終製品の曲げ
強度は原料のポルトランドセメント100重量部に
対したCaCO3を６重量部加えたときが最大であ
り、10重量部以上加えた場合には無添加のときよ
りも曲げ強度が低化することが判かる。ポルトラ
ンドセメント100重量部に対してCaCO3を８重量
部加えることは、このCaCO3をCaOに換算して
対セメント重量比で表現すると4.48重量％のCaO
を添加することと等価である。従つて、第１表
は、カルシウム化合物をCaOに換算して対セメン
ト重量比で５％以下に加えることにより、製品の
曲げ強度をより増大させることが可能であること
を示していると言えるのである。本発明によつて
得られたセメント製品の曲げ強度が増大する理由
は、セメントの粒子間に存在するゲルポアと呼ば
れる微小空隙（直径26Å以下）やキヤピリーポア
と呼ばれる小空隙（直径26Å以上）よりなる空隙
部にCaOが比較的多量に浸入し、空隙部に浸入し
たCaOはやがて吸湿によりCa（OH）2となり、こ
れによつて体積が膨張して空隙部に充填状態とな
るからである。かかる空隙部の充填による効果
は、第１に、充填によりセメント粒子間距離が短
かくなる結果、フアンデワールズ力が大きくなつ
て強度向上に寄与することであり、第２に、充填
Ca（OH）2が炭酸化されることにより、厚い硬化
表層を有すると同時に密な組織が比較的短時間の
うちに形成され、強度向上に寄与することであ
り、第３に、上記の如き密な組織がカルシウム化
合物の膨張力に耐えながら形成されるため、いわ
ゆるケミカルストレスが作用して強度向上に寄与
することである。
本発明により製造したセメント製品の機械的強
度を、製造過程に焼成工程を組みラ入れない従来
法によつて製造したセメント製品と比較するため
に、次の如き対比試験を行つた。すなわち、セメ
ントと骨材との配合割合が１：２となるように調
合した原料に対し、対セメント重量比（CaOに換
算しない値）2.0％のCaCO3を添加したものに水
を加え混練してなるセメント混練物を加圧成形し
て得たセメント成形小片１〜６を、本発明方法の
工程順に従つて、１週間湿気中養生の後、800℃
で10分間焼成してから３週間水中養生することに
よつて得た製品（Ａ群）と、セメントと骨材の配
合割合が上と同一（１：２）となるように調合し
た原料に対し、単に水のみを加えて混練してなる
セメント混練物を上と同一条件で加圧成形して得
たセメント成形小片1′〜6′を従来法によつて、４
週間水中養生することによつて得た製品（Ｂ群）
との曲げ強度を試験したところ第２表の如き結果
が得られた。なお、セメント成形小片１〜６及び
1′〜6′の大きさはすべて210×30×30mm、使用骨
材の種類は、試験片１（1′）が８メツシユアンダ
ーで嵩比重が2.39の磁器質シヤモツト、同２
（2′）が８メツシユアンダーで嵩比重が2.36の磁
器質シヤモツト、同３（3′）が35メツシユアンダ
ーの磁器質シヤモツト、同４（4′）が８メツシユ
アンダーの陶器質シヤモツト、同５（5′）が35メ
ツシユアンダーの抗火石、同６（6′）が水滓であ
る。また使用試験装置は、東京衡機株式会社の小
型材料試験機FSP−500であり、試験条件はスパ
ン間隔90mm、荷重速度12mm/minであつた。[Table] As is clear from Table 1, the bending strength of the final product is maximum when 6 parts by weight of CaCO 3 is added to 100 parts by weight of raw material Portland cement, and when 10 parts by weight or more is added. It can be seen that the bending strength is lower than when no additive is added. Adding 8 parts by weight of CaCO 3 to 100 parts by weight of Portland cement means that when this CaCO 3 is converted to CaO and expressed as a weight ratio to cement, it is 4.48% by weight of CaO.
This is equivalent to adding . Therefore, it can be said that Table 1 shows that it is possible to further increase the bending strength of the product by adding calcium compounds to a weight ratio of 5% or less to cement in terms of CaO. be. The reason why the bending strength of the cement products obtained by the present invention is increased is due to the voids that exist between the cement particles, consisting of microscopic voids (26 Å or less in diameter) called gel pores and small voids (26 Å or more in diameter) called capillary pores. This is because a relatively large amount of CaO infiltrates into the voids, and the CaO that has entered the voids eventually absorbs moisture and becomes Ca(OH) 2 , which expands in volume and fills the voids. The effects of filling such voids are, firstly, that filling shortens the distance between cement particles, which increases the Juan de Waals force and contributes to improving the strength.
By carbonating Ca(OH) 2 , a dense structure with a thick hardened surface layer is formed in a relatively short period of time, contributing to improved strength. Thirdly, as mentioned above, Since a dense structure is formed while enduring the expansion force of the calcium compound, so-called chemical stress acts and contributes to improving the strength. In order to compare the mechanical strength of the cement product manufactured according to the present invention with that of a cement product manufactured by a conventional method that does not incorporate a firing process into the manufacturing process, the following comparative test was conducted. In other words, water is added to the raw materials mixed so that the mixing ratio of cement and aggregate is 1:2, CaCO 3 is added at a weight ratio of 2.0% to the cement (value not converted to CaO), and the mixture is kneaded. Cement molded pieces 1 to 6 obtained by pressure molding a cement kneaded material made of
For the products obtained by baking for 10 minutes in water and curing in water for 3 weeks (group A), and for the raw materials mixed so that the mixing ratio of cement and aggregate was the same as above (1:2). , Cement molded pieces 1' to 6' obtained by press-molding a cement mixture obtained by simply adding and kneading water under the same conditions as above were molded into 4 pieces by a conventional method.
Products obtained by curing in water for a week (group B)
When the bending strength was tested, the results shown in Table 2 were obtained. In addition, cement molded pieces 1 to 6 and
The sizes of 1' to 6' are all 210 x 30 x 30 mm, and the types of aggregates used are: Test specimen 1 (1') is porcelain shamotsu with 8 mesh under and bulk specific gravity of 2.39;
(2') is a porcelain shim with 8 mesh under and a bulk specific gravity of 2.36, 3 (3') is a porcelain shim with 35 mesh under, and 4 (4') is a ceramic shim with 8 mesh under. , 5 (5') is a 35 mesh under firestone, and 6 (6') is a water slag. The test equipment used was a small material testing machine FSP-500 manufactured by Tokyo Hoshiki Co., Ltd., and the test conditions were a span interval of 90 mm and a loading rate of 12 mm/min.
【表】
上記第２表から明らかな如く、いずれの骨材を
用いた場合においても、原料にカルシウム化合物
を添加し、且つ焼成工程を組み込んだ本発明方法
による製品（Ａ群）の方が、焼成工程のない従来
法による製品（Ｂ群）に比してその曲げ強度は大
きくなつている。
本発明の効果は、単に製品の機械的強度が優れ
ている点に止まるものではない。本発明方法を採
用することによる最大のメリツトは、高温焼成に
よつて機械的強度の迅向上を図ることができるた
め、セメント製品に燻化処理と高融点釉薬の施釉
とを可能にした点にある。殊にセメント製品の施
釉に際し、従来は使用不可能とされていた安価で
はあるが融点が高いフリツト釉が使用可能になつ
たこと、並びにこのフリツト釉に長石、粘度等の
生原料を適宜に配合して、第３表及び第４表に例
示する如き、耐候性・耐磨耗性・耐薬品性に優れ
ると同時に施釉面の色彩・光沢に申し分のない、
セメント製品に好適の釉薬が使用できるようにな
つたことによつて、建築界をはじめ関連産業分野
において、セメント製品の新規且つ広範な需要を
生み出し得る点に、本発明の極めて優れた産業上
の利用可能性が認められるであろう。
第 ３ 表
M25フリツト 10部
1121フリツト 20部
ガラス粉 65部
ZnO ５部
第 ４ 表
3909フリツト 20部
ガラス粉 60部
長 石 10部
粘 土 ５部
ZrO3 ５部[Table] As is clear from Table 2 above, no matter which aggregate is used, the products produced by the method of the present invention (Group A) in which a calcium compound is added to the raw material and a calcination step is incorporated are more effective. Its bending strength is higher than that of products produced by the conventional method (Group B) without a firing process. The effects of the present invention are not limited to simply superior mechanical strength of the product. The biggest advantage of adopting the method of the present invention is that it is possible to quickly improve mechanical strength through high-temperature firing, making it possible to smoke and glaze cement products with a high-melting-point glaze. be. In particular, when glazing cement products, it has become possible to use fritted glaze, which is inexpensive but has a high melting point, which was previously considered unusable, and it has also become possible to appropriately mix raw materials such as feldspar and viscosity into this fritted glaze. As exemplified in Tables 3 and 4, the glazed surface has excellent weather resistance, abrasion resistance, and chemical resistance, as well as impeccable color and gloss of the glazed surface.
The extremely excellent industrial advantage of the present invention is that it is now possible to use a suitable glaze for cement products, creating new and wide-ranging demand for cement products in the construction industry and other related industrial fields. Availability will be acknowledged. Table 3 M25 frit 10 parts 1121 frit 20 parts Glass powder 65 parts ZnO 5 parts Table 4 3909 frit 20 parts Glass powder 60 parts Stone 10 parts Clay 5 parts ZrO 3 5 parts
Claims (1)
てのカルシウム化合物を、CaOに換算して対セメ
ント重量比で５％以下加えたものに水を加え、更
に必要に応じて補強材を加えてなる原料を十分に
混練する原料混練工程と、この混練物を所望の形
状に成形する成形工程と、この成形体を予備的に
水和硬化させる予備的水和硬化工程と、この予備
的水和硬化体の表面に高融点の釉薬を施す施釉工
程と、この施釉硬化体を650〜950℃で焼成する焼
成工程と、この焼成体を十分に水和硬化させる本
格的水和硬化工程とを、この順序で行うことを特
徴とするセメント製品の製造方法。 ２ 前記補強材として、ガラス繊維、セラミツク
繊維、金属繊維又は金属線を用いることを特徴と
する特許請求の範囲第１項記載のセメント製品の
製造方法。 ３ 前記高融点の釉薬として、長石、粘土等の生
原料にフリツト釉を配合した又は配合せずして作
つた生釉、フリツト釉又は揮発釉を用いることを
特徴とする特許請求の範囲第１項に記載のセメン
ト製品の製造方法。 ４ 前記焼成工程における焼成は、還元性の雰囲
気中において燻化剤を燻焼させることにより、燻
化剤中に含まれる炭化水素が熱分解することによ
つて生じる微粒状炭素を焼成対象物の表面に沈着
させるようにして、行われることを特徴とする特
許請求の範囲第１項に記載のセメント製品の製造
方法。[Claims] 1. A calcium compound as an additive is added to cement and aggregate as the main raw materials in an amount of 5% or less by weight of cement in terms of CaO, and then water is added, and if necessary, A raw material kneading step of sufficiently kneading the raw material with a reinforcing material added thereto, a molding step of molding this kneaded material into a desired shape, and a preliminary hydration hardening step of preliminarily hydrating and hardening this molded product, A glazing process in which a high-melting-point glaze is applied to the surface of this preliminary hydrated and hardened body, a firing process in which this glazed and hardened body is fired at 650 to 950°C, and a full-scale hydration process in which this fired body is sufficiently hydrated and hardened. A method for manufacturing a cement product, characterized in that a curing step is performed in this order. 2. The method for manufacturing a cement product according to claim 1, wherein glass fiber, ceramic fiber, metal fiber, or metal wire is used as the reinforcing material. 3. Claim 1, characterized in that the high melting point glaze is a raw glaze, fritted glaze, or volatile glaze made by blending or not blending fritted glaze with raw materials such as feldspar or clay. Method for producing cement products as described in Section. 4. In the firing step, the smoking agent is smoked in a reducing atmosphere to remove particulate carbon from the object to be fired due to thermal decomposition of hydrocarbons contained in the smoking agent. The method for manufacturing a cement product according to claim 1, characterized in that the method is carried out by depositing it on a surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP251084A JPS59141476A (en) | 1984-01-09 | 1984-01-09 | Manufacture of cement products |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP251084A JPS59141476A (en) | 1984-01-09 | 1984-01-09 | Manufacture of cement products |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59141476A JPS59141476A (en) | 1984-08-14 |
| JPS6152116B2 true JPS6152116B2 (en) | 1986-11-12 |
Family
ID=11531365
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP251084A Granted JPS59141476A (en) | 1984-01-09 | 1984-01-09 | Manufacture of cement products |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59141476A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59199591A (en) * | 1983-04-27 | 1984-11-12 | 積水化学工業株式会社 | Manufacture of cement formed body |
| JPS6212682A (en) * | 1985-07-10 | 1987-01-21 | 株式会社イナックス | Manufacture of glazed cement product |
| JPS6317274A (en) * | 1986-07-08 | 1988-01-25 | 東海コンクリ−ト工業株式会社 | Manufacture of dressing cement product |
| JPS63107878A (en) * | 1986-10-23 | 1988-05-12 | 株式会社イナックス | Glazed cementitious thin plate and manufacture |
-
1984
- 1984-01-09 JP JP251084A patent/JPS59141476A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59141476A (en) | 1984-08-14 |
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