JPH0352419B2 - - Google Patents
Info
- Publication number
- JPH0352419B2 JPH0352419B2 JP59153429A JP15342984A JPH0352419B2 JP H0352419 B2 JPH0352419 B2 JP H0352419B2 JP 59153429 A JP59153429 A JP 59153429A JP 15342984 A JP15342984 A JP 15342984A JP H0352419 B2 JPH0352419 B2 JP H0352419B2
- Authority
- JP
- Japan
- Prior art keywords
- dust
- copolymer
- concrete
- spraying
- water
- 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 - Lifetime
Links
- 239000000428 dust Substances 0.000 claims description 61
- 239000003795 chemical substances by application Substances 0.000 claims description 40
- 238000005507 spraying Methods 0.000 claims description 38
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 28
- 230000003449 preventive effect Effects 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 21
- 229920001577 copolymer Polymers 0.000 claims description 19
- 238000010276 construction Methods 0.000 claims description 17
- 239000007864 aqueous solution Substances 0.000 claims description 12
- 229920002401 polyacrylamide Polymers 0.000 claims description 12
- 239000000243 solution Substances 0.000 claims description 12
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 9
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 9
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 8
- 230000002265 prevention Effects 0.000 claims description 8
- 239000011230 binding agent Substances 0.000 claims description 7
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 claims description 7
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 claims description 6
- 150000002148 esters Chemical class 0.000 claims description 6
- 239000004317 sodium nitrate Substances 0.000 claims description 4
- 230000007062 hydrolysis Effects 0.000 claims description 3
- 238000006460 hydrolysis reaction Methods 0.000 claims description 3
- 239000003112 inhibitor Substances 0.000 claims description 3
- 235000010344 sodium nitrate Nutrition 0.000 claims description 3
- ABBZJHFBQXYTLU-UHFFFAOYSA-N but-3-enamide Chemical compound NC(=O)CC=C ABBZJHFBQXYTLU-UHFFFAOYSA-N 0.000 claims 1
- 238000004581 coalescence Methods 0.000 claims 1
- 239000004567 concrete Substances 0.000 description 42
- 239000004568 cement Substances 0.000 description 17
- -1 sulfate ester salt Chemical class 0.000 description 15
- 239000000203 mixture Substances 0.000 description 10
- 239000007921 spray Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 229920006322 acrylamide copolymer Polymers 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 229910052602 gypsum Inorganic materials 0.000 description 5
- 239000010440 gypsum Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 239000004094 surface-active agent Substances 0.000 description 5
- 238000004090 dissolution Methods 0.000 description 4
- 239000010419 fine particle Substances 0.000 description 4
- 239000011378 shotcrete Substances 0.000 description 4
- 239000004570 mortar (masonry) Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000005086 pumping Methods 0.000 description 3
- 239000002562 thickening agent Substances 0.000 description 3
- 239000002202 Polyethylene glycol Substances 0.000 description 2
- 235000014113 dietary fatty acids Nutrition 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000194 fatty acid Substances 0.000 description 2
- 229930195729 fatty acid Natural products 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000011490 mineral wool Substances 0.000 description 2
- 239000002736 nonionic surfactant Substances 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 229920001223 polyethylene glycol Polymers 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000008431 aliphatic amides Chemical class 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 229920003086 cellulose ether Polymers 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000003925 fat Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000004079 fireproofing Methods 0.000 description 1
- 150000002430 hydrocarbons Chemical group 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000002075 main ingredient Substances 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 229920005615 natural polymer Polymers 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229920001451 polypropylene glycol Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229930195734 saturated hydrocarbon Natural products 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
- 229920001059 synthetic polymer Polymers 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 230000005641 tunneling Effects 0.000 description 1
- 229930195735 unsaturated hydrocarbon Natural products 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Description
本発明は、モルタル、およびコンクリートの吹
付け工事、およびセメント、石膏等の水硬性無機
結合材を用いる吹付け工事の施工時に発生する粉
じんを防止するための新規な粉じん防止剤並びに
粉じん防止方法に関する。
モルタル吹付けは、のり面防護、ライニング等
に、コンクリート吹付けは、のり面防護、トンネ
ルの一次覆工などに多く用いられている。また、
セメント、石膏等の水硬性無機結合材を用いるそ
の他の吹付け工事としては、ロツクウール等の耐
火材や他の軽量骨材と、セメント、石膏等の水硬
性無機結合材、および水からなる配合組成物を吹
付ける耐火壁、耐火被覆材等の吹付け工事があ
る。
吹付けコンクリートには一般に型わくを省略
できる、急速施工が可能である、作業の省力
化ができる、などの長所がある。このため、最近
新しいトンネル工法として、掘削後直ちに地山表
面にコンクリートを吹付けて地山の崩壊を防ぐと
ともに、ロツクボルトを打ち込んで岩盤を支持す
るNATM（New Austrian Tunnelling Nethod）
の適用がわが国でも本格化してきている。コンク
リート吹付け工法には、水以外の材料（セメン
ト、骨材、急結剤等）を混合したドライミツクス
を水と別系統で圧送し、吹付けホース先端のノズ
ル付近で水と合流、混合したものを施工面に吹付
ける乾式方式と、急結剤を除く全部の材料をミキ
サで練りまぜたコンクリートをノズルへ送り、ノ
ズル付近で急結剤を添加混合した後、施工面に吹
付ける湿式方式とがある。
乾式方式は、施工されるコンクリートの配合が
ノズル部で供給される水量によつて変化するこ
と、すなわちコンクリートの品質がある程度ノズ
ルマンの技術によつて左右されるという制約もあ
るが、施工設備が比較的簡便なこと、圧送距離を
長くできること、急結剤の添加も比較的容易であ
ること、等の長所があり、トンネル工事における
吹付けに用いられている。また、湿式方式に関し
ては、従来、圧送距離をあまり長くできないこ
と、急結剤の使用が困難であること等の理由か
ら、主に法面防護などの明り工事に多く用いられ
ていたが、最近これらの問題も解決し品質の安定
したコンクリートを、取り扱いが簡易で、吐出能
力が比較的大きい吹付け機で施工する新しい技術
が開発されトンネル工事への適用も本格的となり
つつある。
しかし、これらの吹付け工事では、セメント、
石膏、ロツクウール、あるいは必要に応じて使用
される急結剤（主成分、炭酸ソーダ、アルミン酸
ソーダ、ケイ酸ソーダ等）等の無機材料の微細な
粒子あるいは繊維が吹付け施工時に飛散すること
により大量の粉じんが発生する。この粉じんは作
業環境上の問題点のひとつとされており、しかも
トンネル工事では、その低滅を図り作業環境を改
善するために換気設備を設置する等の対策がまだ
必ずしも十分でないのが実状である。粉じんは、
コンクリートを高圧で吹付ける際に生じる乱流が
セメントや骨材の微細粒子を分離、飛散すること
により生じる。とくに乾式方式の場合、セメン
ト、骨材、急結剤のドライミツクスがノズル付近
で水と混合されるため、ドライミツクスと水の接
触が不完全のまま吹付けられ「濡れ」の不十分な
微細なセメント粒子等が飛散して発生するものと
考えられる。一方湿式方式の場合、粉じんの発生
は乾式に対して一般的には比較的少なく、これは
粉体としてのセメントが存在しないことが主な要
困と考えられるが、セメントペーストの一部がノ
ズルからの吐出の際に微小な霧状の粒子となつて
飛散すること、また、急結剤が粉末である場合に
は、その一部がコンクリートと十分に混合されな
いまま、吐出して飛散すること等の現象があげら
れる。
近年、これら粉じんの問題を解決するために、
メチルセルロース等の天然高分子化合物やポリエ
チレンオキサイドあるいは分子量の非常に高い
（例えば1000万以上）ポリアクリルアミド、アク
リルアミドとアクリル酸の共重合体等の合成高分
子化物を、粉じん防止剤としてコンクリートに添
加することによつてコンクリートそのものの粘性
を増加し、吹付け時の微細粒子の分離飛散を防止
しようとの試みが行われている。しかし、これら
従来の増粘剤系の粉じん防止剤は、いずれも水へ
の溶解に長時間（30分〜１時間以上）を要した
り、溶解作業を注意深く行わないと、いわゆる
“ママコ”を生じ実質的に溶解が不可能になる場
合がある。また、これらは極く少量の溶解で溶液
の粘性が急増し、溶液の輸送性、取り扱い性が悪
くなるため、１％以下の希薄水溶液でしか扱えな
い。しかもコンクリートに配合される水の量は、
水セメント比により限定されるので粉じん防止剤
のコンクリートへの添加量も制限される。また水
への溶解の手間を省くために粉末状のまま、セメ
ント、骨材等のドライミツクス中にあらかじめ混
合して使用すると、その溶解性の悪さのために効
果が十分に発揮されない。
他に、ばらつきなどにより添加量が若干増加す
るとコンクリートの粘稠性が必要以上に増加し、
乾式方式においては、ノズル部での閉塞が起こり
やすくなる等の問題を生じる。また、生コンクリ
ートを圧送する湿式方式では、圧送時の負荷がい
ちじるしく増大することがある。
本発明の目的は容易に水に溶解し、従来の増粘
剤系の粉じん防止剤に比較して取扱いが極めて簡
便で作業効率のよい粉じん防止剤を提供すること
にある。また本発明の他の目的は、コンクリート
の粘稠性を必要以上に増加させることがなく、し
たがつて、圧送ホース、ノズル等での閉塞や、吹
付施工の作業効率低下をひきおこすことなく、乾
式方式にも湿式方式にも適用できる新規な粉じん
防止剤並びに粉じん防止方法を提供することにあ
る。
即ち、本発明は、分子量30万〜200万〔極限粘
度（30℃、1N−硝酸ナトリウム水溶液）1.5〜7.0
dl／ｇ〕のポリアクリルアミドの部分加水分解物
またはアクリルアミドとアクリル酸、メタクリル
酸及びそれらのエステルからなる群から選ばれる
少なくとも１種との共重合体または該共重合体の
部分加水分解物のみを含むセメント、石膏などの
水硬性無機結合剤を用いる吹付け工法粉じん防止
剤並びに分子量30万〜200万〔極限粘度（30℃、
1N−硝酸ナトリウム水溶液）1.5〜7.0dl／ｇ〕の
ポリアクリルアミドの部分加水分解物またはアク
リルアミドとアクリル酸、メタクリル酸及びそれ
らのエステルからなる群から選ばれる少なくとも
１種の共重合体または該共重合体の部分加水分解
物を含む１％を超える水溶液として水硬性無機結
合剤と水とを混合後施工面に吹付ける工法の水中
に添加して吹付け工法における粉じんを防止する
方法に関する。
ポリアクリルアミドの加水分解物またはアクリ
ルアミドとアクリル酸、メタクリル酸およびそれ
らのエステルの共重合体または該共重合体の部分
加水分解物の分子量が粉じん防止効果に及ぼす影
響は大きい。本発明では、上記ポリアクリルアミ
ドの部分加水分解物またはアクリルアミド共重合
体あるいは該共重合体の部分加水分解物の分子量
が約30万〜200万である。分子量30万未満では、
増粘性が弱くなり、効果を出すのに多量の添加量
を要し、不経済である。また、添加量が多くなる
と、コンクリートの凝結時間や強度に悪影響を与
えるため、実際上使用できない。200万を超える
と、水への溶解性が悪くなり、また、水溶液の粘
性があがりすぎるためにポンプ等による取り扱い
が困難になる。
ポリアクリルアミドの加水分解率あるいはアク
リルアミド共重合体または該共重合体の部分加水
分解物中のアクリル酸およびメタクリル酸の含有
率または加水分解率は、モル百分率で、一般には
50％以下、好ましくは３〜30％である。
本発明の粉じん防止方法では上記ポリアクリル
アミドの部分加水分解物あるいはアクリルアミド
共重合体または該共重合体の部分加水分解物のみ
よりなる本発明の粉じん防止剤の水溶液中または
必要あればこの溶液中ににポリエチレングリコー
ル型非イオン界面活性剤を添加してもよい。
ポリエチレングリコール型非イオン界面活性
剤、およびその硫酸エステル塩としては、それぞ
れ下記一般式で示される。
(1) 高級アルコールのエチレンオキサイド付加
物、およびその硫酸エステル塩
Ｒ−Ｏ−（CH2−CH2−Ｏ−）oＸ
(2) アルキルフエノールエチレンオキサイド付加
物、およびその硫酸エステル塩
(3) 脂肪酸エチレンオキサイド付加物、およびそ
の硫酸エステル塩
Ｒ−COO−（CH2−CH2−Ｏ−）oＸ
(4) 高級アルキルアミンエチレンオキサイド付加
物、およびその硫酸エステル塩
(5) 脂肪族アミドのエチレンオキサイド付加物、
およびその硫酸エステル塩
(6) ポリプロピレングリコール・エチレンオキサ
イド付加物およびその硫酸エステル塩
（ここでＲは、炭素数８〜25の飽和および未飽
和炭化水素基、ｌ，ｍ，ｎは１〜50の整数、
Ｘ，X′はＨまたは−SO3Mで、ＭはNa，Ｋ等
のアルカリ金属およびNH4）
の他、多価アルコールの脂肪酸エステル・エチレ
ンオキサイド付加物、油脂のエチレンオキサイド
付加物、およびそれらの硫酸エステル塩等があげ
られる。この界面活性剤を併用する場合には、前
記ポリアクリルアミドの部分加水分解物またはア
クリルアミド共重合体あるいは該共重合体の部分
加水分解物と界面活性剤との配合割合は一般的に
は９：１〜１：９である。
本発明ではポリアクリルアミドの部分加水分解
物またはアクリルアミド共重合体あるいは該共重
合体の部分加水分解物を予め１％を超える水溶液
とし、乾式工法においては、コンクリート吹付け
用添加水に、湿式工法においては、コンクリート
練りまぜ水に所定量となるようにし、添加する。
また、それらの給水ポンプと連動させた定量注入
ポンプにより、給水ラインに所定量を連続注入し
てもよい。
本発明の粉じん防止剤の添加量は、通常、吹付
けコンクリートのセメント重量に対して0.01〜５
％、より好ましくは0.05〜1.0％である。５％を
大巾に越える添加は、コンクリートの凝結および
強度発現に悪影響を与えるので好ましくない。
上記分子量のポリアクリルアミド部分加水分解
物、アクリルアミドとアクリル酸、メタアクリル
酸またはそれらのエステルからなる共重合体ある
いは該共重合体の部分加水分解物は、従来の増粘
剤系の粉じん防止剤に比べ、増粘性がずつて少な
く水への溶解性が良い。従つて、本発明の粉じん
防止剤は吹付けノズルや圧送ホースを閉塞するこ
とがない上、溶解に特別な装置を必要とせず、濃
厚溶液を定量ポンプで直接添加することができる
など作業性に優れる。また、コンクリート、モル
タル中の微細なセメント粒子等を十分に凝集する
と同時に、コンクリートの粘稠性を適度に増加し
吹付け時に発生する粉じんを減少させることがで
きる。
上記界面活性剤は、湿潤、浸透効果等の界面活
性作用により、吹付け施工時に粉じん源となる無
機鉱物質微粒子等の水への濡れ性を改善する。従
つて、この界面活性剤を併用すれば、より粉じん
の発生を抑制することができる。
以下、実施例により本発明を説明する。
実施例 １〜13 比較例 １〜５
本発明の粉じん防止剤を、乾式のコンクリート
吹付け工法に適用し、コンクリート吹付け時の粉
じん発生量を粉じん防止剤無添加の場合と比較し
た。
後記表−１に示す配合にしたがい計量、混合し
たセメントと骨材（細骨材、粗骨材）および急結
剤のドライミツクスを吹付け機に供給し、吹付け
機により吐出圧約3.5Kg／cm3で空気圧送した。吹
付けノズルの手前約3mのところで、別に高圧ポ
ンプにより送られてきた、所定量の粉じん防止剤
を含む水を添加し、混合物を吹付けノズルより施
工面に吹付けた。
本発明の粉じん防止剤は、吹付け機台車上に置
いた容積約50のタンクに５〜10％の水溶液を用
意し、これを添加水を送る高圧ポンプのサクシヨ
ン側配管に高圧ポンプと連動させた定量注入ポン
プ（ダイヤフラム式）により、所定添加率になる
ように連続注入した。このため現場における粉じ
ん低減剤の溶解作業は、一切必要としなかつた。
これに対して、比較例で示したポリアクリルア
ミド部分加水分解物（分子量約1000万）の場合に
は、溶液の粘性が高く（0.15％溶液で約700cps）、
高濃度溶液がつくれないため、あらかじめ１回の
施工に必要な水約600に粉じん防止剤を所定の
添加量になるように溶解（0.1〜0.2％）したもの
を用意した。このため、吹付け機の横に撹拌機付
きの約１m3のタンクを新たに設置する必要があつ
た。また、溶解速度が遅く、かつ“ママコ”をつ
くらないように溶解する必要があるため、１回の
施工に必要な量の粉じん防止剤水溶液を用意する
のに30分〜１時間の作業を要した。また、水溶液
の粘性が上がるために比較例３の添加量以上に上
げることが実際上できなかつた。
コンクリート吹付け時に発生する粉じん量は、
吹付けノズルからの距離約5mの位置でデジタル
粉じん計により測定した。測定は吹付け開始時よ
り終了時まで５分間隔で行なつた。１回のコンク
リートの吹付け量は約４m3、所要時間は約45分で
あつた。
粉じん量測定の他に、粉じん防止剤添加がコン
クリートに与える影響をみるために、パネル型わ
く（50×50×20cm）にコンクリートを吹付け、硬
化後JISに従つて円柱形コア供試体（φ7.5cm）を
切取り、材令28日で圧縮強度試験を行なつた。
粉じん量測定結果、および吹付けコンクリート
の強度試験の結果は表−２に示す通りであり、本
発明の粉じん防止剤を用いることにより粉じんの
発生を大巾に抑制できることが明らかである。し
かも、本発明の粉じん防止剤を用いても施工上問
題となるような顕著なコンクリートの凝結遅延お
よび強度の低下は認められなかつた。
The present invention relates to a new dust prevention agent and dust prevention method for preventing dust generated during spraying work of mortar and concrete, and spraying work using hydraulic inorganic binders such as cement and gypsum. . Mortar spraying is often used for slope protection, lining, etc., and concrete spraying is often used for slope protection, primary lining of tunnels, etc. Also,
For other spraying work using hydraulic inorganic binders such as cement and gypsum, a mixture composition consisting of fireproofing materials such as rock wool or other lightweight aggregates, hydraulic inorganic binders such as cement and gypsum, and water is used. There is spraying work for fireproof walls, fireproof coatings, etc. Shotcrete generally has the advantages of omitting molds, rapid construction, and labor-saving work. For this reason, a new tunnel construction method has recently been developed called NATM (New Austrian Tunneling Nethod), in which concrete is sprayed onto the ground surface immediately after excavation to prevent the ground from collapsing, and rock bolts are driven in to support the rock.
The application of this technology is gaining momentum in Japan as well. The concrete spraying method involves pumping dry mixes mixed with materials other than water (cement, aggregate, quick-setting agents, etc.) through a separate system from the water, and combining and mixing with the water near the nozzle at the end of the spray hose. There is a dry method in which concrete is sprayed onto the construction surface, and a wet method in which concrete is mixed with all materials except for the quick-setting agent in a mixer, sent to a nozzle, the quick-setting agent is added and mixed near the nozzle, and then sprayed onto the construction surface. There is. The dry method has the limitation that the mix of concrete to be applied changes depending on the amount of water supplied at the nozzle, that is, the quality of the concrete depends to some extent on the technique of the nozzleman, but the construction equipment is comparatively It is used for spraying in tunnel construction because of its advantages such as being simple, allowing long pressure-feeding distances, and relatively easy addition of quick-setting agents. In addition, the wet method has traditionally been mainly used for lighting work such as slope protection because the distance of pressure cannot be extended very long and it is difficult to use quick-setting agents. A new technology has been developed that solves these problems and uses a spraying machine that is easy to handle and has a relatively large discharge capacity to produce concrete of stable quality, and its application to tunnel construction is becoming widespread. However, in these spraying works, cement,
Fine particles or fibers of inorganic materials such as gypsum, rock wool, or quick-setting agents used as necessary (main ingredients: soda carbonate, sodium aluminate, sodium silicate, etc.) are scattered during spraying. A large amount of dust is generated. This dust is considered to be a problem in the working environment, and the reality is that measures such as installing ventilation equipment to reduce dust and improve the working environment are not always sufficient in tunnel construction. be. Dust is
This occurs when the turbulent flow that occurs when concrete is sprayed under high pressure separates and scatters fine particles of cement and aggregate. In particular, in the case of the dry method, the dry mix of cement, aggregate, and quick-setting agent is mixed with water near the nozzle, so the contact between the dry mix and the water is incomplete and the mixture is sprayed, resulting in fine cement that is insufficiently ``wet''. It is thought that this is caused by particles etc. scattering. On the other hand, in the case of the wet method, dust generation is generally relatively low compared to the dry method, and this is thought to be mainly due to the absence of powdered cement. When the quick-setting agent is discharged from the concrete, it becomes fine mist-like particles and scatters. Also, if the quick-setting agent is a powder, some of it is discharged and scattered without being sufficiently mixed with the concrete. Examples of such phenomena include: In recent years, in order to solve these dust problems,
Adding natural polymer compounds such as methylcellulose, polyethylene oxide, or synthetic polymers such as polyacrylamide with a very high molecular weight (e.g., 10 million or more) or a copolymer of acrylamide and acrylic acid to concrete as a dust preventive agent. Attempts have been made to increase the viscosity of concrete itself to prevent the separation and scattering of fine particles during spraying. However, all of these conventional thickener-based dust preventive agents require a long time to dissolve in water (30 minutes to 1 hour or more), and if the dissolution process is not done carefully, they can cause so-called "mamako". may occur, making dissolution virtually impossible. Further, even if these are dissolved in a very small amount, the viscosity of the solution increases rapidly, impairing the transportation and handling properties of the solution, so that it can only be handled as a dilute aqueous solution of 1% or less. Moreover, the amount of water mixed in concrete is
Since it is limited by the water-cement ratio, the amount of dust preventive agent added to concrete is also limited. Furthermore, if the powder is mixed in advance into dry mixes such as cement and aggregates in order to save the trouble of dissolving it in water, the effect will not be sufficiently exerted due to its poor solubility. In addition, if the amount added increases slightly due to variations, the viscosity of the concrete will increase more than necessary.
In the dry method, problems such as clogging at the nozzle section occur easily. In addition, in the wet method of pumping fresh concrete, the load during pumping may increase significantly. An object of the present invention is to provide a dust preventive agent that is easily dissolved in water, is extremely easy to handle, and has high working efficiency compared to conventional thickener-based dust preventive agents. Another object of the present invention is to provide a dry method that does not increase the viscosity of concrete more than necessary, and therefore does not cause blockages in pressure hoses, nozzles, etc., or reduce the work efficiency of spraying construction. It is an object of the present invention to provide a new dust prevention agent and a dust prevention method that can be applied to both wet and wet methods. That is, the present invention has a molecular weight of 300,000 to 2,000,000 [intrinsic viscosity (30°C, 1N aqueous sodium nitrate solution) of 1.5 to 7.0]
dl/g] of polyacrylamide, or a copolymer of acrylamide and at least one member selected from the group consisting of acrylic acid, methacrylic acid, and their esters, or only a partial hydrolyzate of the copolymer. Spraying method dust inhibitors using hydraulic inorganic binders such as cement and gypsum, and molecular weight 300,000 to 2 million [intrinsic viscosity (30℃,
1N-sodium nitrate aqueous solution) 1.5 to 7.0 dl/g] of a partial hydrolyzate of polyacrylamide, or a copolymer of acrylamide and at least one kind selected from the group consisting of acrylic acid, methacrylic acid, and their esters, or the copolymer. This invention relates to a method for preventing dust in a spraying method by adding an aqueous solution of more than 1% containing a partially hydrolyzed product to water in which a hydraulic inorganic binder and water are mixed and then sprayed onto the construction surface. The molecular weight of a polyacrylamide hydrolyzate, a copolymer of acrylamide, acrylic acid, methacrylic acid, and their esters, or a partial hydrolyzate of the copolymer has a large influence on the dust prevention effect. In the present invention, the molecular weight of the partial hydrolyzate of polyacrylamide, the acrylamide copolymer, or the partial hydrolyzate of the copolymer is about 300,000 to 2,000,000. If the molecular weight is less than 300,000,
The thickening properties become weaker, and a large amount is required to produce the effect, making it uneconomical. Moreover, if the amount added is too large, it will have a negative effect on the setting time and strength of concrete, so it cannot be used in practice. If it exceeds 2 million, the solubility in water becomes poor and the viscosity of the aqueous solution increases too much, making it difficult to handle with a pump or the like. The hydrolysis rate of polyacrylamide or the content or hydrolysis rate of acrylic acid and methacrylic acid in an acrylamide copolymer or a partial hydrolyzate of the copolymer is expressed as a molar percentage, and generally
It is 50% or less, preferably 3 to 30%. In the dust prevention method of the present invention, the dust prevention agent of the present invention consisting only of the partial hydrolyzate of polyacrylamide or the acrylamide copolymer or the partial hydrolyzate of the copolymer is added to the aqueous solution or, if necessary, to this solution. A polyethylene glycol type nonionic surfactant may be added to the surfactant. The polyethylene glycol type nonionic surfactant and its sulfate ester salt are each represented by the following general formula. (1) Ethylene oxide adduct of higher alcohol and its sulfuric ester salt R-O-(CH 2 -CH 2 -O-) o X (2) Alkylphenol ethylene oxide adduct and its sulfuric ester salt (3) Fatty acid ethylene oxide adduct and its sulfuric ester salt R-COO-(CH 2 -CH 2 -O-) o X (4) Higher alkylamine ethylene oxide adduct and its sulfuric ester salt (5) ethylene oxide adduct of aliphatic amide;
and its sulfate ester salts (6) Polypropylene glycol/ethylene oxide adduct and its sulfate ester salt (Here, R is a saturated or unsaturated hydrocarbon group having 8 to 25 carbon atoms, l, m, and n are integers of 1 to 50,
X, X' are H or -SO 3 M, M is an alkali metal such as Na, K, etc. and NH 4 ), fatty acid ester/ethylene oxide adducts of polyhydric alcohols, ethylene oxide adducts of fats and oils, and Examples include sulfate ester salts of When this surfactant is used in combination, the mixing ratio of the partial hydrolyzate of polyacrylamide or acrylamide copolymer, or the partial hydrolyzate of the copolymer and the surfactant is generally 9:1. ~1:9. In the present invention, a partial hydrolyzate of polyacrylamide, an acrylamide copolymer, or a partial hydrolyzate of the copolymer is made into an aqueous solution of more than 1% in advance, and in the dry method, it is added to the added water for concrete spraying, and in the wet method, is added to concrete mixing water in a specified amount.
Further, a predetermined amount may be continuously injected into the water supply line by a metering pump linked with those water supply pumps. The amount of the dust preventive agent of the present invention added is usually 0.01 to 5% based on the cement weight of shotcrete.
%, more preferably 0.05 to 1.0%. Addition of more than 5% is undesirable since it adversely affects the setting and strength development of concrete. Partially hydrolyzed polyacrylamide with the above molecular weight, a copolymer of acrylamide and acrylic acid, methacrylic acid, or their esters, or a partially hydrolyzed copolymer can be used as a conventional thickener-based dust preventive agent. In comparison, it has less viscosity and better solubility in water. Therefore, the dust preventive agent of the present invention does not block the spray nozzle or pressure hose, does not require special equipment for dissolution, and has improved workability, such as the ability to directly add a concentrated solution with a metering pump. Excellent. In addition, it is possible to sufficiently aggregate fine cement particles in concrete and mortar, and at the same time to appropriately increase the viscosity of concrete and reduce dust generated during spraying. The above-mentioned surfactant improves the wettability of inorganic mineral fine particles, etc., which are a source of dust during spraying, to water through surface active effects such as wetting and penetrating effects. Therefore, if this surfactant is used in combination, the generation of dust can be further suppressed. The present invention will be explained below with reference to Examples. Examples 1 to 13 Comparative Examples 1 to 5 The dust preventive agent of the present invention was applied to a dry concrete spraying method, and the amount of dust generated during concrete spraying was compared with that when no dust preventive agent was added. Cement, aggregate (fine aggregate, coarse aggregate), and quick-setting agent Drymix are weighed and mixed according to the formulation shown in Table 1 below, and are supplied to a spraying machine at a discharge pressure of approximately 3.5Kg/cm. Pneumatically delivered at 3 . Approximately 3 m in front of the spray nozzle, water containing a predetermined amount of anti-dust agent, which was sent separately by a high-pressure pump, was added, and the mixture was sprayed onto the construction surface from the spray nozzle. The dust preventive agent of the present invention is prepared by preparing a 5 to 10% aqueous solution in a tank with a volume of approximately 50 ml placed on a spray machine trolley, and feeding this solution to the suction side piping of a high-pressure pump that sends added water in conjunction with the high-pressure pump. Continuous injection was carried out using a metered injection pump (diaphragm type) to achieve a predetermined addition rate. Therefore, there was no need to dissolve the dust reducing agent at all on site. In contrast, in the case of the polyacrylamide partial hydrolyzate (molecular weight approximately 10 million) shown in the comparative example, the viscosity of the solution was high (approximately 700 cps for a 0.15% solution);
Since it was not possible to make a highly concentrated solution, we prepared a pre-dissolved anti-dust agent (0.1-0.2%) in the approximately 600 ml of water needed for one application. For this reason, it was necessary to install a new tank of about 1 m 3 with an agitator next to the spray machine. In addition, because the dissolution rate is slow and it is necessary to dissolve the solution without creating "mamako", it takes 30 minutes to 1 hour to prepare the amount of dust preventive agent aqueous solution required for one application. did. Furthermore, since the viscosity of the aqueous solution increased, it was practically impossible to increase the amount added beyond that of Comparative Example 3. The amount of dust generated during concrete spraying is
The dust was measured using a digital dust meter at a distance of approximately 5 m from the spray nozzle. Measurements were carried out at 5 minute intervals from the start of spraying to the end of spraying. The amount of concrete sprayed at one time was approximately 4 m 3 and the time required was approximately 45 minutes. In addition to measuring the amount of dust, in order to see the effect of adding a dust preventive agent on concrete, concrete was sprayed onto a panel type frame (50 x 50 x 20 cm), and after curing, a cylindrical core specimen (φ7 .5cm) was cut and a compressive strength test was conducted at 28 days old. The results of measuring the amount of dust and the strength test of shotcrete are shown in Table 2, and it is clear that the dust generation can be greatly suppressed by using the dust preventive agent of the present invention. Furthermore, even when the dust preventive agent of the present invention was used, no significant concrete setting delay or decrease in strength, which would cause problems during construction, was observed.
【表】
＊ 粉末急結剤
[Table] * Powder quick setting agent
【表】【table】
【表】
実施例 14，15 比較例 ６，７
NATMで施工され、湿式でコンクリート吹付
けが行なわれている某山岳トンネル工事で、本発
明の粉じん防止剤を湿式吹付け工法に適用し、コ
ンクリート吹付け時の粉じん発生量を、粉じん防
止剤無添加の場合と比較した。
後記表−３に示す配合に従い計量されたセメン
ト、骨材（砂、砂利）および所定量の混和剤（流
動化剤）を含有した水を連続練りミキサーで練り
まぜ生コンクリートとして吹付け機に供給した。
吹付け機より吐出圧約4.5Kg／cm3で空気圧送した
コンクリートに、吹付けノズル付近で、別に空気
圧送した粉末急結剤を添加混合し、吹付けノズル
より施工面に吹付けた。
本発明の粉じん防止剤は、所定の添加率になる
ように混和剤（流動化剤）と一緒に水に溶解し、
これを連続練りミキサに既設の混和剤タンク（容
量100）に貯え、これを既設の設備により、練
りまぜ水と一定の割合になるように添加して、生
コンクリートの練りまぜを行つた。これに対し
て、比較例で示したセルロースエーテル系の粉じ
ん防止剤の場合には、水溶液の粘性が上がりすぎ
るために水溶液としての添加ができず、粉末をそ
のままセメントに一定比率になるように添加混合
して用いた。
コンクリート吹付け時の粉じん発生量は、吹付
けノズルからの距離約5mの位置でデジタル粉じ
ん計により測定した。測定は吹付け開始時より終
了時まで５分間隔で行なつた。１回の吹付けの所
要時間は、約30分、コンクリートの吹付け量は約
2.5m3である。
粉じん量測定の他に、粉じん防止剤添加がコン
クリートに与える影響をみるために、パネル型わ
く（50×50×20cm）にコンクリートを吹付け、硬
化後、円柱形コア供試体（φ7.5cm）を切取り、材
令28日で圧縮強度試験を行なつた。
粉じん量測定結果、および吹付けコンクリート
の強度試験の結果は表−４に示す通りであり、湿
式吹付け工法においても、本発明の粉じん防止剤
を用いることにより粉じんの発生を大巾に抑制で
きることが明らかである。しかも、本発明の粉じ
ん防止剤を用いても施工上問題となるような顕著
なコンクリートの凝結遅延および強度の低下は認
められなかつた。[Table] Examples 14 and 15 Comparative Examples 6 and 7 In a certain mountain tunnel construction project conducted by NATM, where wet concrete spraying was carried out, the dust preventive agent of the present invention was applied to the wet spraying method, and concrete The amount of dust generated during spraying was compared with that when no dust inhibitor was added. Cement, aggregate (sand, gravel), and water containing a predetermined amount of admixture (plasticizer) measured according to the formulation shown in Table 3 below are mixed in a continuous mixer and supplied to the spraying machine as ready-mixed concrete. did.
Concrete was pneumatically delivered from a spraying machine at a discharge pressure of approximately 4.5 kg/cm 3 , and a powder quick-setting agent, which was separately delivered by air, was added and mixed near the spraying nozzle, and the mixture was sprayed onto the construction surface from the spraying nozzle. The dust preventive agent of the present invention is dissolved in water together with an admixture (plasticizer) at a predetermined addition rate,
This was stored in an existing admixture tank (capacity 100) in a continuous mixing mixer, and added to mixing water at a certain ratio using existing equipment to mix ready-mixed concrete. On the other hand, in the case of the cellulose ether-based dust preventive agent shown in the comparative example, the viscosity of the aqueous solution increases too much, so it cannot be added as an aqueous solution, so the powder is added as is to the cement at a fixed ratio. They were mixed and used. The amount of dust generated during concrete spraying was measured using a digital dust meter at a distance of approximately 5 m from the spray nozzle. Measurements were carried out at 5 minute intervals from the start of spraying to the end of spraying. The time required for one shot is approximately 30 minutes, and the amount of concrete sprayed is approximately
It is 2.5m3 . In addition to measuring the amount of dust, in order to see the effect of adding a dust preventive agent on concrete, concrete was sprayed onto a panel-shaped frame (50 x 50 x 20 cm), and after curing, a cylindrical core specimen (φ7.5 cm) was used. The material was cut out and a compressive strength test was conducted when the material was 28 days old. The results of measuring the amount of dust and the strength test of shotcrete are shown in Table 4, which shows that even in the wet spraying method, the dust generation can be greatly suppressed by using the dust preventive agent of the present invention. is clear. Moreover, even when the dust preventive agent of the present invention was used, no significant concrete setting delay or decrease in strength, which would cause problems during construction, was observed.
【表】
＊ 粉末急結剤
[Table] * Powder quick setting agent
Claims (1)
硝酸ナトリウム水溶液）1.5〜7.0dl／ｇ〕のポリ
アクリルアミドの部分加水分解物またはアリルア
ミドとアクリル酸、メタクリル酸およびそれらの
エステルから成る群から選ばれる少なくとも１種
との共重合体または該共重合体の部分加水分解物
のみを含むことを特徴とする水硬性無機結合剤を
用いる吹付工法用粉じん防止剤。 ２ 加水分解率または共重合体のアクリル酸、メ
タクリル酸の含有率が３〜30％（モル百分率）で
ある特許請求の範囲第１項記載の粉じん防止剤。 ３ 水硬性無機結合剤と水とを混合後施工面に吹
付ける吹付け工法における粉じん防止方法におい
て、分子量30万〜200万〔極限粘度（30℃、1N−
硝酸ナトリウム水溶液）1.5〜7.0dl／ｇ〕のポリ
アクリルアミドの部分加水分解物またはアクリル
アミドとアクリル酸、メタクリル酸およびそれら
のエステルから成る群から選ばれる少くとも１種
との共重合体または該共重合体の部分加水分解物
の１％を超える水溶液として前記水に添加するこ
とを特徴とする吹付け工法における粉じん防止方
法。[Claims] 1. Molecular weight 300,000 to 2,000,000 [Intrinsic viscosity (30°C, 1N-
aqueous sodium nitrate solution) 1.5 to 7.0 dl/g] of polyacrylamide, or a copolymer of allylamide and at least one member selected from the group consisting of acrylic acid, methacrylic acid, and their esters, or the copolymer thereof A dust preventive agent for spraying construction using a hydraulic inorganic binder characterized by containing only a partially hydrolyzed product of. 2. The dust inhibitor according to claim 1, wherein the hydrolysis rate or the content of acrylic acid or methacrylic acid in the copolymer is 3 to 30% (mole percentage). 3 In the dust prevention method in the spraying method, in which a hydraulic inorganic binder and water are mixed and then sprayed onto the construction surface,
aqueous sodium nitrate solution) 1.5 to 7.0 dl/g] or a copolymer of acrylamide with at least one member selected from the group consisting of acrylic acid, methacrylic acid, and their esters, or the copolymer thereof A method for preventing dust in a spraying method, characterized in that an aqueous solution containing more than 1% of a partially hydrolyzed product of coalescence is added to the water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15342984A JPS6131335A (en) | 1984-07-24 | 1984-07-24 | Dust proofing agent |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15342984A JPS6131335A (en) | 1984-07-24 | 1984-07-24 | Dust proofing agent |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6131335A JPS6131335A (en) | 1986-02-13 |
| JPH0352419B2 true JPH0352419B2 (en) | 1991-08-09 |
Family
ID=15562319
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15342984A Granted JPS6131335A (en) | 1984-07-24 | 1984-07-24 | Dust proofing agent |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6131335A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3825162A1 (en) * | 1988-07-23 | 1990-02-08 | Henkel Kgaa | DUST BINDING AGENT FOR THE CONCRETE SPRAYING PROCESS (I) |
| DE3825161A1 (en) * | 1988-07-23 | 1990-01-25 | Henkel Kgaa | DUST BINDERS FOR THE CONCRETE SPRAYING PROCESS (II) |
| CN104163442B (en) * | 2014-08-06 | 2016-03-23 | 四川天齐锂业股份有限公司 | Dustless stage monohydrate lithium hydroxide and preparation method |
| JP7421310B2 (en) * | 2019-11-13 | 2024-01-24 | 花王株式会社 | Adhesion reducing agent for pipes for spraying hydraulic compositions |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59102852A (en) * | 1982-11-29 | 1984-06-14 | 東亞合成株式会社 | Dust reducing agent for spray concrete |
| JPS59174554A (en) * | 1983-03-22 | 1984-10-03 | 東亞合成株式会社 | Dust reducing agent for spray concrete |
-
1984
- 1984-07-24 JP JP15342984A patent/JPS6131335A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59102852A (en) * | 1982-11-29 | 1984-06-14 | 東亞合成株式会社 | Dust reducing agent for spray concrete |
| JPS59174554A (en) * | 1983-03-22 | 1984-10-03 | 東亞合成株式会社 | Dust reducing agent for spray concrete |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6131335A (en) | 1986-02-13 |
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