JP2004238793A - Rock wool spray method - Google Patents
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- JP2004238793A JP2004238793A JP2002379937A JP2002379937A JP2004238793A JP 2004238793 A JP2004238793 A JP 2004238793A JP 2002379937 A JP2002379937 A JP 2002379937A JP 2002379937 A JP2002379937 A JP 2002379937A JP 2004238793 A JP2004238793 A JP 2004238793A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
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Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、施工性が良好で、吹付後の脱落がなく、高強度で耐火性能に優れた被覆層が得られる半乾式ロックウール吹付工法に関する。
【０００２】
【従来の技術】
鉄骨造建物の梁、柱、壁等を耐火被覆するためのロックウール吹付工法には、乾式工法、湿式工法、半乾式工法がある。
乾式工法は、予めロックウールとセメントを混合した乾燥混合物を吹付ノズルから吐出し、同時に水を別送して吹付ノズルに配置した噴射口から吐出し、両者を混合して吹付ける工法である。この工法では、施工時にセメント及びロックウールによる発塵が著しく、作業環境上の問題があった。また、吹付後の硬化体は軽量であるものの、脆いため、衝撃や振動により破損しやすいという問題もあった。
【０００３】
湿式工法は、ロックウール、セメント等の主材と、増粘剤、界面活性剤等の助剤からなる原料に水を加え、ミキサーで混練してスラリー状とし、これをポンプで圧送し、圧縮空気により吹付ノズルから吹付ける工法である。この工法では、粉塵の発生はないが、スラリーを高圧で圧送するための大型装置が必要となり、吹付装置の設置及びそのメンテナンスが煩雑になる。また、ロックウール及びセメント以外に助剤を添加する必要があるため、材料コストが高く、更に、その施工には熟練を要するため、施工コストも高いという問題があった。
【０００４】
半乾式工法は、ロックウールとセメントスラリーを別送し、吹付用ノズル部分でこれらを混合して吹付ける工法である。この工法は、セメントスラリーを用いるため、粉塵の発生をかなり防止することができるが、乾式工法と同様に、吹付後の硬化体は軽量であるため、脆く、衝撃や振動により破損しやすい。硬化体強度及び耐火性能を向上させるため、かさ密度を高くするには、ロックウールとセメントスラリーの比率を変更するか、４０〜６０質量％程度の高濃度のセメントスラリーを用いる必要がある。通常、半乾式工法で用いられるセメントスラリーの濃度は３３．３質量％で、ロックウール：セメントスラリー中のセメントの質量比は、６：４程度である。このセメントスラリー濃度でセメントスラリーの比率を上げる、すなわちセメントスラリー量を多くすると、かさ密度は高くなるものの、吹付層における余剰水が多くなり、吹付後に脱落しやすくなる。また、高濃度のセメントスラリーを用いた場合には、セメントスラリー中のセメント沈降に伴うホースの閉塞や、粘度上昇による圧送不良が発生し、施工性が著しく悪くなるという問題が生じる。
【０００５】
また、高密度の被覆層を得るために、ロックウール、セメント及び水を含有する湿潤混合物と、セメントスラリーを別送し、吹付用ノズル部分でこれらを混合して吹付ける工法（特許文献１）も提案されている。しかし、湿潤混合物は圧送性が悪く、圧送ホース内面に湿潤混合物が付着し、ホースを閉塞するおそれがある。
【０００６】
【特許文献１】
特許第３２５６５３６号明細書
【０００７】
【発明が解決しようとする課題】
従って、本発明の目的は、施工性が良好で、吹付後の脱落がなく、高密度で耐火性能に優れた被覆層が得られる半乾式ロックウール吹付工法を提供することにある。
【０００８】
【課題を解決するための手段】
かかる実情において、本発明者らは鋭意検討を行った結果、セメントスラリーに二水石膏を併用することにより、上記課題を解決できることを見出した。
【０００９】
すなわち、ロックウールを吹付ノズルへ圧送し、同時に水硬性セメント及び二水石膏を合計で４０〜６０質量％含有するセメントスラリーを吹付ノズルへ別送し、吹付ノズル内で両者を吐出させ混合しながら吹付ノズルから吐出させ、又は吹付ノズルから両者をそれぞれ吐出させながら混合し、被耐火被覆物に吹付けて耐火被覆層を形成させることを特徴とするロックウール吹付工法を提供するものである。
【００１０】
【発明の実施の形態】
本発明で用いるロックウールとしては、通常のロックウール吹付工法に用いられるものであれば良く、その繊維径や、形態、粒状の場合の粒径等は、特に制限されずに用いることができる。
【００１１】
本発明で用いる水硬性セメントとしては、普通ポルトランドセメント、早強ポルトランドセメント、白色セメント等のポルトランドセメント；アルミナセメント等の特殊セメント；都市ゴミ焼却灰や下水汚泥焼却灰を主原料として製造されたエコセメント；その他、各種混合セメントなどを用いることができる。
【００１２】
また、二水石膏としては、補強紙を除いた石膏ボード廃材を乾式粉砕したものや、排脱二水石膏を用いることもできる。セメントスラリーに二水石膏を配合することにより、スラリー中のセメントの沈降を防止することができ、また、吹付後の被覆層の耐火性が高められる。
【００１３】
二水石膏の粒径は、１．５ｍｍ以下、特に１．０ｍｍ以下であるのが好ましい。二水石膏の粒径が１．５ｍｍを超えると、セメントスラリーを吐出するために吹付ノズルに配置されたセメントスラリー用噴射口を閉塞しやすいので施工性が著しく悪くなり、また、噴射口が閉塞しないように噴射口の径を大きくすると、ロックウールとセメントスラリーとの混合が不均一となりやすく、粉塵の発生を招く等の問題を生じることがあり、好ましくない。
【００１４】
本発明におけるセメントスラリーの沈降速度は、使用される二水石膏の粒度が細かすぎると速くなるので、本発明で用いる二水石膏は、目開き１４９μｍの篩を用いて篩分けしたときの残分（粗粒分）が占める割合が５０質量％以上であるのが好ましい。粗粒分の占める割合が５０質量％未満では、セメントスラリーの沈降速度が速くなり、セメントスラリーを圧送する際にホース内で閉塞を招く場合がある。これらの条件を有する二水石膏は、例えば補強紙を除いた石膏ボード廃材を粉砕すれば容易に得ることができる。この場合、補強紙が多少石膏ボード廃材に残存していたとしても、特に問題とはならない。
【００１５】
水硬性セメントと二水石膏は、質量比が２：１〜１：２、特に１．５：１〜１：１．５で用いるのが好ましい。水硬性セメントの割合がこの範囲を超えると、スラリーの沈降が速く、ホースが閉塞しやすくなり、二水石膏の割合がこの範囲を超えると、硬化体の硬さや下地への接着性が低下する傾向があり、好ましくない。
【００１６】
また、水硬性セメントと二水石膏は、スラリー中に合計で４０〜６０質量％、好ましくは４５〜５５質量％含有される。４０質量％未満では、高密度の被覆層を得るためにセメントスラリー量を過剰に添加する必要があり、これにより脱落等が発生するため十分な施工性が得られず、６０質量％を超えると、スラリーの濃度が高く、圧送負荷が大きいため、大型のスラリーポンプが必要となり好ましくない。
なお、セメントスラリーは、水硬性セメント及び二水石膏を、上記の割合で水と混合することにより、調製することができる。
【００１７】
さらに、セメントスラリーには、流動化剤を含有させることができ、粘度を調整することができる。流動化剤としては、例えばナフタレン系流動化剤、ポリカルボン酸系流動化剤、メラミン系流動化剤等を用いることができる。これらの流動化剤は、スラリー中の水硬性セメント及び二水石膏の合計質量に対して、外割で０．１〜２質量％、特に０．５〜１．５質量％配合するのが好ましい。
【００１８】
セメントスラリーの粘度は、２５℃において、１０〜５００ｍＰａ・ｓであるのが、施工性の点で好ましい。セメントスラリーの粘度が高い場合には、上記流動化剤を用いて、このような粘度範囲に調整するのが好ましい。
【００１９】
本発明においては、上記のようなロックウール及びセメントスラリーを用い、通常の半乾式吹付工法に従って吹付を行う。すなわち、ロックウールを吹付ノズルへ圧送し、同時にセメントスラリーを吹付ノズルへ別送し、吹付ノズル内で両者を吐出させ混合しながら吹付ノズルから吐出させ、又は吹付ノズルから両者をそれぞれ吐出させながら混合して吹付ける。
より具体的には、例えば、吹付ノズルの中央部にロックウール吐出方向と平行にセメントスラリー用導管及び噴射口を設けるか、又はロックウール吐出方向に対して直角に吹付ノズル内部に複数の噴射口を設け、吹付ノズル内で両者を混合して鉄骨等の被耐火被覆物に吹付ける。また、吹付ノズルの先端部にセメントスラリー用噴射口を多数設け、ロックウールとセメントスラリーをそれぞれ吹付ノズルから吐出させながら混合して吹付けることもできる。
このようにして吹付を行うことにより、被耐火被覆物に耐火被覆層を形成させることができる。
【００２０】
吹付を行う際の、ロックウールと、セメントスラリー中の水硬性セメント及び二水石膏の合計との混合割合は、ロックウールが３０〜５０質量％、特に３５〜４５質量％で、水硬性セメント及び二水石膏の合計量が５０〜７０質量％、特に５５〜６５質量％であるのが好ましい。
【００２１】
【実施例】
次に、実施例及び比較例を挙げて本発明を更に説明する。
【００２２】
参考例１
図１に示す組成になるよう、粉体である普通ポルトランドセメント及び二水石膏に、水を混合してセメントスラリーを調製した。図１中の記号Ａ〜Ｄについては、二水石膏は使用せず、記号Ｅ〜Ｊについては、廃石膏ボードを粉砕して得た１４９μｍ篩残分６５質量％で粒径１．５ｍｍを超えるものは含まない二水石膏を使用し、記号Ｋについては、廃石膏ボードを粉砕して得た１４９μｍ篩全通の二水石膏を使用した。
これらのセメントスラリーを２００ｍＬメスシリンダーに投入・静置し、各経過時間におけるスラリー中の粉体の沈降体積を測定し、次式により、スラリー沈降率を求めた。結果を図１に示す。
【００２３】
【数１】
図１より、本発明で用いる二水石膏を含有するセメントスラリーは、二水石膏を使用しないセメントスラリーよりも粉体の沈降が防止されている。また、二水石膏を使用した場合、１４９μｍ篩残分６５質量％で粒径１．５ｍｍを超えるものは含まない二水石膏を使用したセメントスラリーは、１４９μｍ篩全通の二水石膏を使用したセメントスラリーよりも粉体の沈降率が小さい。
【００２５】
実施例１〜２、比較例１〜２
攪拌装置付のスラリー槽に、表１に示す組成の粉体原料と水を入れ、これらを約１０分間攪拌して、セメントスラリーを調製した。なお、セメントとしては普通ポルトランドセメント（ＪＩＳ Ａ ５２１０）、二水石膏は、補強紙を除いた石膏ボード廃材を粉砕機により乾式粉砕し、目開き１．５ｍｍの篩いを全通し（粒径１．５ｍｍ以下）、１４９μｍ篩残分６５質量％のもの、流動化剤はナフタレン系流動化剤（マイティ１５０、花王社製）、水は水道水を用いた。
市販の粒状綿であるロックウールをブロア圧送機により圧送し、同時に、スラリーポンプを用いて上記スラリーを表１の配合比率になるよう流量を調整して圧送し、両者を吹付ノズル内で混合し、４００×２００×８×１３ｍｍ、長さ２．５ｍのＨ形鋼に吹付け、脱落等の状況を確認した。ここで、吹付ノズルから吐出されるロックウールの吐出量は３ｋｇ／分、セメントスラリーの吐出量は表１の配合比率となるようにそれぞれ流量を調整した。なお、Ｈ形鋼への吹付厚さは５０ｍｍとした。
【００２６】
次に、同様に、寸法５０×１００ｍｍ、長さ１ｍのコ字型鋼板の内面側、１８０×１９０×３．２ｍｍの鉄板に吹付け施工を行った。コ字型鋼板に吹付けたものについて、吹付け直後から下縁を接地しない状態で１時間鉛直静置させ、吹付材の含水率の分布を測定した。また、鉄板に吹付けたものについて、かさ密度、１０％歪み時の圧縮応力、耐火時間を測定した。これらの結果を表１に併せて示す。
【００２７】
（評価方法）
（１）吹付１時間後の含水率鉛直分布：
コ字型鋼板に吹付施工し、下縁を接地しない状態で１時間鉛直静置した後、コ字型鋼板の内面側の吹付材を１０ｃｍ間隔で切断して質量を測定した。次に、４０℃及び１０５℃で恒量になるまで乾燥して乾燥後の質量を測定し、次式により、吹付材の各含水率を求めた。
【００２８】
【数２】
（２）かさ密度：
４０℃及び１０５℃で恒量になるまで乾燥後、外寸法をノギスで測定して体積を求めるとともに、質量を測定し、次式によりかさ密度を求めた。
かさ密度（ｇ／ｃｍ３）＝ 質量（ｇ） ／ 体積（ｃｍ３）
【００３０】
（３）１０％歪み時の圧縮応力：
１０５℃で乾燥した後、５０×５０×５０ｍｍに切断し、上面より載荷し、厚さ方向において１０％歪みが生じたときの荷重から、次式により求めた。
圧縮応力（Ｐａ）＝ １０％歪み時の圧縮荷重（Ｎ） ／ 載荷面積（ｍ２）
【００３１】
（４）耐火時間：
クロメル−アルメル（ＪＩＳ Ｃ １６０２ 記号Ｋ）熱電対を中央に埋め込んだ１８０×１９０×３．２ｍｍの鉄板に耐火被覆材を厚さ約３２ｍｍに吹付施工し、養生及び乾燥して試験体とする。その後、内部温度が１０００℃に保たれた電気炉入口に裏面をセラミックボードで被覆した試験体を設置し、試験体における鉄板の裏面温度が３５０℃になるまでの時間（分）を耐火時間とした。
【００３２】
【表１】
【発明の効果】
本発明によれば、施工性が良好で、吹付後の脱落がなく、高強度で耐火性能に優れた被覆層を得ることができる。
【図面の簡単な説明】
【図１】各種濃度のセメントスラリーについて、各経過時間における沈降率を示す図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semi-dry rock wool spraying method which has good workability, does not fall off after spraying, and provides a coating layer having high strength and excellent fire resistance.
[0002]
[Prior art]
Rock wool spraying methods for refractory coating of beams, columns, walls, etc. of steel-framed buildings include dry methods, wet methods, and semi-dry methods.
The dry method is a method in which a dry mixture in which rock wool and cement are mixed in advance is discharged from a spray nozzle, water is separately fed and discharged from an injection port arranged in the spray nozzle, and the two are mixed and sprayed. In this method, dust is generated by cement and rock wool at the time of construction, and there is a problem in working environment. Further, although the cured body after spraying is light in weight, it is brittle, so that there is a problem that the cured body is easily damaged by impact or vibration.
[0003]
In the wet method, water is added to a raw material consisting of a main material such as rock wool and cement, and an auxiliary agent such as a thickener and a surfactant, and the mixture is kneaded with a mixer to form a slurry, which is pumped by a pump and compressed. This is a method of blowing air from a blowing nozzle. Although no dust is generated by this method, a large-sized device for pumping the slurry at a high pressure is required, and the installation and maintenance of the spraying device are complicated. In addition, there is a problem in that an auxiliary agent needs to be added in addition to rock wool and cement, so that the material cost is high, and furthermore, since the construction requires skill, the construction cost is also high.
[0004]
The semi-dry method is a method in which rock wool and cement slurry are separately fed, mixed and sprayed at a spray nozzle portion. In this method, since a cement slurry is used, the generation of dust can be considerably prevented. However, as in the case of the dry method, the cured body after spraying is light in weight, brittle, and easily damaged by impact or vibration. In order to increase the bulk density in order to improve the strength of the cured product and the fire resistance, it is necessary to change the ratio of rock wool to the cement slurry or use a cement slurry having a high concentration of about 40 to 60% by mass. Usually, the concentration of the cement slurry used in the semi-dry method is 33.3% by mass, and the mass ratio of rock wool: cement in the cement slurry is about 6: 4. When the cement slurry ratio is increased at this cement slurry concentration, that is, when the cement slurry amount is increased, the bulk density is increased, but the excess water in the sprayed layer is increased, and it is easy to fall off after spraying. In addition, when a high-concentration cement slurry is used, the clogging of the hose due to the sedimentation of the cement in the cement slurry and poor pumping due to an increase in viscosity occur, causing a problem that the workability is significantly deteriorated.
[0005]
In addition, in order to obtain a high-density coating layer, a method of separately sending a wet mixture containing rock wool, cement and water and a cement slurry and mixing and spraying them at a spray nozzle portion (Patent Document 1). Proposed. However, the wet mixture has poor pumpability, and the wet mixture may adhere to the inner surface of the pumping hose and block the hose.
[0006]
[Patent Document 1]
Patent No. 3256536 specification
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a semi-dry rock wool spraying method which has good workability, does not fall off after spraying, and provides a coating layer having high density and excellent fire resistance.
[0008]
[Means for Solving the Problems]
Under such circumstances, the present inventors have conducted intensive studies, and as a result, have found that the above problem can be solved by using gypsum dihydrate together with a cement slurry.
[0009]
That is, rock wool is pressure-fed to the spray nozzle, and simultaneously, a cement slurry containing a total of 40 to 60% by mass of hydraulic cement and gypsum is separately sent to the spray nozzle, and both are discharged and mixed in the spray nozzle while spraying. It is intended to provide a rock wool spraying method characterized in that a fire-resistant coating is formed by discharging a nozzle or mixing both of them while discharging from a spray nozzle, and spraying the mixture on a fire-resistant material to form a fire-resistant coating layer.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The rock wool used in the present invention may be any one used in a usual rock wool spraying method, and its fiber diameter, form, and particle size in the case of granular can be used without any particular limitation.
[0011]
Examples of the hydraulic cement used in the present invention include ordinary portland cement, early-strength portland cement, portland cement such as white cement, etc .; special cement such as alumina cement; Cement; in addition, various mixed cements and the like can be used.
[0012]
In addition, as the dihydrate gypsum, dry gypsum of gypsum board waste material excluding reinforcing paper, or drained gypsum plaster can be used. By adding gypsum to the cement slurry, the sedimentation of the cement in the slurry can be prevented, and the fire resistance of the coating layer after spraying can be enhanced.
[0013]
The particle size of the gypsum is preferably 1.5 mm or less, particularly preferably 1.0 mm or less. If the particle diameter of gypsum dihydrate exceeds 1.5 mm, the injection port for the cement slurry arranged in the spray nozzle to discharge the cement slurry is easily blocked, so that the workability is significantly deteriorated, and the injection port is blocked. If the diameter of the injection port is increased so as not to cause the mixing, the mixing of the rock wool and the cement slurry tends to be uneven, which may cause problems such as generation of dust, which is not preferable.
[0014]
Since the sedimentation speed of the cement slurry in the present invention increases when the particle size of the gypsum used is too fine, the gypsum used in the present invention is a residue obtained by sieving using a sieve having an opening of 149 μm. It is preferable that the proportion occupied by (coarse particles) is 50 mass% or more. If the proportion of the coarse particles is less than 50% by mass, the sedimentation speed of the cement slurry is increased, and the cement slurry may be clogged in the hose when being pumped. Gypsum with these conditions can be easily obtained by grinding gypsum board waste material excluding reinforcing paper, for example. In this case, even if some reinforcing paper remains in the gypsum board waste material, there is no particular problem.
[0015]
The hydraulic cement and the gypsum are preferably used in a mass ratio of 2: 1 to 1: 2, particularly 1.5: 1 to 1: 1.5. If the ratio of the hydraulic cement exceeds this range, the sedimentation of the slurry is fast, and the hose is likely to be clogged.If the ratio of gypsum exceeds this range, the hardness of the cured body and the adhesion to the substrate decrease. Tends to be undesirable.
[0016]
The hydraulic cement and gypsum are contained in the slurry in a total amount of 40 to 60% by mass, preferably 45 to 55% by mass. If the amount is less than 40% by mass, it is necessary to add an excessive amount of cement slurry to obtain a high-density coating layer. In addition, since the concentration of the slurry is high and the pumping load is large, a large-sized slurry pump is required, which is not preferable.
The cement slurry can be prepared by mixing hydraulic cement and gypsum dihydrate with water in the above ratio.
[0017]
Further, a fluidizing agent can be contained in the cement slurry, and the viscosity can be adjusted. As the fluidizing agent, for example, a naphthalene-based fluidizing agent, a polycarboxylic acid-based fluidizing agent, a melamine-based fluidizing agent, or the like can be used. It is preferable that these fluidizers are added in an amount of 0.1 to 2% by mass, particularly 0.5 to 1.5% by mass, based on the total mass of the hydraulic cement and the gypsum in the slurry. .
[0018]
The viscosity of the cement slurry at 25 ° C. is preferably 10 to 500 mPa · s from the viewpoint of workability. When the viscosity of the cement slurry is high, it is preferable to adjust the viscosity to such a range using the fluidizing agent.
[0019]
In the present invention, spraying is performed by using the above-mentioned rock wool and cement slurry according to a normal semi-dry spraying method. That is, rock wool is pressure-fed to the spray nozzle, and simultaneously the cement slurry is separately fed to the spray nozzle, and both are discharged and mixed in the spray nozzle and discharged from the spray nozzle, or mixed while discharging both from the spray nozzle. Spray.
More specifically, for example, a conduit for cement slurry and an injection port are provided in the center of the spray nozzle in parallel with the rock wool discharge direction, or a plurality of injection ports are provided inside the spray nozzle at right angles to the rock wool discharge direction. Are mixed in a spray nozzle and sprayed on a refractory coating such as a steel frame. Also, a number of injection ports for cement slurry may be provided at the tip of the spray nozzle, and rock wool and cement slurry may be mixed and sprayed while being discharged from the spray nozzle.
By performing spraying in this manner, a fire-resistant coating layer can be formed on the fire-resistant coating.
[0020]
When performing the spraying, the mixing ratio of rock wool and the total of hydraulic cement and dihydrate gypsum in the cement slurry is such that rock wool is 30 to 50% by mass, particularly 35 to 45% by mass. It is preferable that the total amount of gypsum is 50 to 70% by mass, particularly 55 to 65% by mass.
[0021]
【Example】
Next, the present invention will be further described with reference to Examples and Comparative Examples.
[0022]
Reference Example 1
Water was mixed with powdered ordinary Portland cement and gypsum dihydrate to obtain the composition shown in FIG. 1 to prepare a cement slurry. For symbols A to D in FIG. 1, gypsum was not used, and for symbols E to J, the particle size exceeded 1.5 mm with a 149 μm sieve residue 65 mass% obtained by grinding waste gypsum board. For the symbol K, gypsum gypsum obtained by pulverizing a waste gypsum board and passing through a 149 μm sieve was used.
These cement slurries were put into a 200 mL measuring cylinder and allowed to stand, and the sedimentation volume of the powder in the slurry at each elapsed time was measured, and the slurry sedimentation rate was determined by the following equation. The results are shown in FIG.
[0023]
(Equation 1)
From FIG. 1, the cement slurry containing gypsum dihydrate used in the present invention can prevent the sedimentation of powder more than the cement slurry not using gypsum dihydrate. In the case of using gypsum dihydrate, a cement slurry using gypsum dihydrate not containing a 149 μm sieve residue of 65% by mass and having a particle size of more than 1.5 mm used gypsum gypsum through a 149 μm sieve. The sedimentation rate of powder is smaller than that of cement slurry.
[0025]
Examples 1-2, Comparative Examples 1-2
A powdery raw material having the composition shown in Table 1 and water were placed in a slurry tank equipped with a stirrer, and these were stirred for about 10 minutes to prepare a cement slurry. In addition, ordinary Portland cement (JIS A 5210) is used as cement, and gypsum is used for dry gypsum of gypsum board waste material excluding reinforcing paper. A 149 μm sieve residue 65% by mass, a naphthalene-based fluidizing agent (Mighty 150, manufactured by Kao Corporation) as a fluidizing agent, and tap water as water.
Rock wool, which is a commercially available granular cotton, is pumped by a blower pump, and at the same time, the slurry is pumped using a slurry pump with the flow rate adjusted to the mixing ratio shown in Table 1, and both are mixed in a spray nozzle. , 400 × 200 × 8 × 13 mm, length 2.5 m, sprayed on H-shaped steel, and the situation such as falling off was confirmed. Here, the flow rate of the rock wool discharged from the spray nozzle was adjusted to 3 kg / min, and the flow rate of the cement slurry was adjusted so as to have the mixing ratio shown in Table 1. The sprayed thickness on the H-section steel was 50 mm.
[0026]
Next, similarly, spraying was performed on an iron plate of 180 × 190 × 3.2 mm on the inner surface side of a U-shaped steel plate having a size of 50 × 100 mm and a length of 1 m. Immediately after spraying, the U-shaped steel sheet was allowed to stand vertically for one hour without contact with the lower edge immediately after spraying, and the distribution of water content of the sprayed material was measured. Moreover, the thing sprayed on the iron plate was measured for bulk density, compressive stress at 10% strain, and fire resistance time. These results are also shown in Table 1.
[0027]
(Evaluation method)
(1) Vertical distribution of water content one hour after spraying:
After spraying construction on a U-shaped steel plate and leaving it to stand vertically for 1 hour without grounding the lower edge, the sprayed material on the inner surface side of the U-shaped steel plate was cut at 10 cm intervals and the mass was measured. Next, it dried at 40 degreeC and 105 degreeC until it became constant weight, the mass after drying was measured, and each moisture content of the spraying material was calculated | required by the following formula.
[0028]
(Equation 2)
(2) Bulk density:
After drying at 40 ° C. and 105 ° C. until a constant weight was obtained, the outer dimensions were measured with calipers to determine the volume, the mass was measured, and the bulk density was determined by the following equation.
Bulk density (g / cm 3 ) = mass (g) / volume (cm 3 )
[0030]
(3) Compressive stress at 10% strain:
After drying at 105 ° C., it was cut into 50 × 50 × 50 mm, loaded from above, and determined by the following equation from the load when 10% strain occurred in the thickness direction.
Compressive stress (Pa) = Compressive load at the time of 10% strain (N) / Loading area (m 2 )
[0031]
(4) Fire resistance time:
A chromel-alumel (JIS C 1602, symbol K) thermocouple is embedded in the center and a fireproof coating material is sprayed to a thickness of about 32 mm on an iron plate of 180 × 190 × 3.2 mm, cured and dried to obtain a test specimen. After that, a specimen whose back surface was covered with a ceramic board was placed at the entrance of the electric furnace where the internal temperature was kept at 1000 ° C., and the time (minute) until the back surface temperature of the iron plate in the specimen reached 350 ° C. was defined as the fire resistance time. did.
[0032]
[Table 1]
【The invention's effect】
According to the present invention, it is possible to obtain a coating layer having good workability, without falling off after spraying, high strength, and excellent fire resistance.
[Brief description of the drawings]
FIG. 1 is a graph showing sedimentation rates at various elapsed times for cement slurries of various concentrations.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002379937A JP4099056B2 (en) | 2002-12-11 | 2002-12-27 | Rock wool spraying method |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002359292 | 2002-12-11 | ||
| JP2002379937A JP4099056B2 (en) | 2002-12-11 | 2002-12-27 | Rock wool spraying method |
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| Publication Number | Publication Date |
|---|---|
| JP2004238793A true JP2004238793A (en) | 2004-08-26 |
| JP4099056B2 JP4099056B2 (en) | 2008-06-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002379937A Expired - Fee Related JP4099056B2 (en) | 2002-12-11 | 2002-12-27 | Rock wool spraying method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008003120A1 (en) * | 2006-07-07 | 2008-01-10 | Asset Systems Pty Ltd | Fire resistant lining system |
| JP2008285390A (en) * | 2007-05-21 | 2008-11-27 | Fujikawa Kenzai Kogyo Kk | Method of forming fireproof composition, fireproof shaped body, fireproof covered structure and fireproof covered layer utilizing waste gypsum |
| JP2013133664A (en) * | 2011-12-27 | 2013-07-08 | Taiheiyo Material Kk | Rock wook spray method and rock wool quality evaluation method |
| JP2021070305A (en) * | 2019-10-29 | 2021-05-06 | 有限会社東京建商 | Stirrer system capable of confirming concentration of cement milk in semi-dry type rock wool spray construction |
-
2002
- 2002-12-27 JP JP2002379937A patent/JP4099056B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008003120A1 (en) * | 2006-07-07 | 2008-01-10 | Asset Systems Pty Ltd | Fire resistant lining system |
| JP2008285390A (en) * | 2007-05-21 | 2008-11-27 | Fujikawa Kenzai Kogyo Kk | Method of forming fireproof composition, fireproof shaped body, fireproof covered structure and fireproof covered layer utilizing waste gypsum |
| JP2013133664A (en) * | 2011-12-27 | 2013-07-08 | Taiheiyo Material Kk | Rock wook spray method and rock wool quality evaluation method |
| JP2021070305A (en) * | 2019-10-29 | 2021-05-06 | 有限会社東京建商 | Stirrer system capable of confirming concentration of cement milk in semi-dry type rock wool spray construction |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4099056B2 (en) | 2008-06-11 |
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