JP7351660B2 - High strength concrete for spraying - Google Patents

High strength concrete for spraying Download PDF

Info

Publication number
JP7351660B2
JP7351660B2 JP2019125873A JP2019125873A JP7351660B2 JP 7351660 B2 JP7351660 B2 JP 7351660B2 JP 2019125873 A JP2019125873 A JP 2019125873A JP 2019125873 A JP2019125873 A JP 2019125873A JP 7351660 B2 JP7351660 B2 JP 7351660B2
Authority
JP
Japan
Prior art keywords
mass
concrete
setting
spraying
quick
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.)
Active
Application number
JP2019125873A
Other languages
Japanese (ja)
Other versions
JP2020011891A (en
Inventor
誉久 羽根井
彰徳 杉山
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Taiheiyo Materials Corp
Original Assignee
Taiheiyo Materials Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Taiheiyo Materials Corp filed Critical Taiheiyo Materials Corp
Publication of JP2020011891A publication Critical patent/JP2020011891A/en
Application granted granted Critical
Publication of JP7351660B2 publication Critical patent/JP7351660B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Landscapes

  • Curing Cements, Concrete, And Artificial Stone (AREA)

Description

本発明は、例えば地山等の掘削面への吹付施工に用いる高強度コンクリートに関する。 The present invention relates to high-strength concrete used for spraying, for example, onto excavated surfaces such as earth.

トンネル、採掘抗、地下空間等の建設では、掘削面の崩壊防止、地山補強の観点から吹付コンクリートが施工されている。吹付コンクリートの施工として、粉塵やリバウンド(跳ね返り)が比較的少ない湿式吹付工法では、セメントと骨材と必要に応じて混和成分を配合したものに水を加えて混練したベースコンクリートに、吹付直前に急結成分とその助剤等からなる液体又は粉体の急結材を添加して急結性を付与し、吹付施工時の付着性を担保している。粉体急結材は液体急結材よりも高い強度を得るのに適している。かかる急結材は、コンクリート輸送管に接続したY字状又はト字状の三方管を介して、圧送中のベースコンクリートに添加され、添加後は吹付け用ノズルまでの移動の短時間に混合がなされ、ノズル端から吹付コンクリートとして吹き出される。 In the construction of tunnels, mining shafts, underground spaces, etc., shotcrete is used to prevent collapse of the excavated surface and to strengthen the ground. In the wet spraying method, which generates relatively little dust and rebound, a mixture of cement, aggregate, and other admixtures as needed is added to base concrete, which is mixed with water, and immediately before spraying. A liquid or powder quick-setting material consisting of a fast-setting component and its auxiliary agent is added to impart quick-setting properties and ensure adhesion during spraying. Powder quick setting materials are suitable for obtaining higher strength than liquid quick setting materials. This rapid setting material is added to the base concrete being pumped through a Y-shaped or T-shaped three-way pipe connected to the concrete transport pipe, and after being added, it is mixed during a short period of time during the journey to the spray nozzle. The concrete is then sprayed out from the nozzle end as shotcrete.

吹き付け付着後のコンクリートに対しては、用途や目的により、例えば材齢28日での一軸圧縮強度が120N/mm2以上という高強度コンクリートを必要とするケースがある。高強度コンクリートを得るには、一般的に、含水量を低くする方策がとられるが、前記のような湿式吹付工法では、含水量を下げると、ベースコンクリートの圧送性が極端に悪化し、急結材との混合性も低下するため、安定した吹付量で均質な吹付コンクリートを得るのが困難になる。減水剤類の配合により低水量でも流動性が高められるが、湿式吹付工法に適した圧送性や混合性を得るには、多量の減水剤類を必要とする。減水剤量の増加は凝結を遅延させ、急結性が阻害される。また、シリカフュームやフライアッシュ等のポゾラン反応性物質をベースコンクリートに配合することで高強度化も可能であるが(例えば、特許文献1参照。)、収縮が大きくなる他、混合水がポゾラン反応にも消費されるため、良好なベースコンクリートの圧送性や急結材との混合性を確保する上で水量を減らすことはできず、初期強度発現性が低迷し易い。水和反応活性が低下し易い低温時の初期強度発現性改善に、アルカリ金属硫酸塩をカルシウムアルミネート類と硫酸アルミニウムの混合物に加えた急結剤(例えば、特許文献2参照。)を使用することも知られている。また、コンクリートの強度の伸びを高めるため、ブレーン比表面積が11000~14000cm2/gのかなり反応活性の高い無水石膏をベースコンクリートに配合し、かつ急結材にも無水石膏を配して、両者を混合させた吹付コンクリートが、反応活性が低下し易い状況下でも、良好な付着性と比較的高い強度発現性が得られることが知られている。(例えば、特許文献3参照。)しかしながら、特に低温のような外的に低活性な環境下でない場合の施工では、硬化が異常に促進され、コンクリートがノズル孔や輸送管内壁に付着して固結し易くなり、孔や管内を閉塞する虞があった。さらに、ベースコンクリート中にかなり高い水和反応活性の石膏が多く含まれると混合水が急速に消費されるため、急結材の混合性が低下し、均質な吹付コンクリートが得られ難くなる。逆に、反応活性の高くない石膏を大量使用すると、凝結遅延作用が際立ってくるめ急結性が阻害され、高い初期強度発現性が得られない。 Depending on the use and purpose, there are cases in which high-strength concrete with an unconfined compressive strength of 120 N/mm 2 or more at 28 days of age is required for concrete after spraying. In order to obtain high-strength concrete, measures are generally taken to lower the water content, but in the wet spraying method described above, lowering the water content will drastically deteriorate the pumpability of the base concrete, resulting in sudden problems. Mixability with binder also decreases, making it difficult to obtain homogeneous shotcrete with a stable spraying amount. Fluidity can be improved even with a low amount of water by adding water-reducing agents, but a large amount of water-reducing agents is required to obtain pumpability and mixability suitable for wet spraying. Increasing the amount of water reducing agent delays setting and inhibits rapid setting. In addition, it is possible to increase the strength by adding pozzolan-reactive substances such as silica fume or fly ash to the base concrete (for example, see Patent Document 1), but this increases shrinkage and also causes the mixed water to react with pozzolan. Since water is also consumed, it is not possible to reduce the amount of water to ensure good pumpability of the base concrete and mixability with the quick setting material, and the initial strength development is likely to be poor. To improve initial strength development at low temperatures where hydration reaction activity tends to decrease, an accelerating agent in which an alkali metal sulfate is added to a mixture of calcium aluminates and aluminum sulfate (see, for example, Patent Document 2) is used. It is also known that In addition, in order to increase the strength of concrete, anhydrite, which has a Blaine specific surface area of 11,000 to 14,000 cm 2 /g and has a fairly high reactivity, is mixed into the base concrete, and anhydrite is also placed as a quick-setting material, so that both It is known that shotcrete mixed with the following can provide good adhesion and relatively high strength development even under conditions where reaction activity is likely to decrease. (For example, see Patent Document 3.) However, especially in construction under low externally active environments such as low temperatures, curing is abnormally accelerated and concrete adheres to the nozzle hole and the inner wall of the transport pipe and hardens. There was a risk that the tube would become easily tied and the hole or inside of the pipe would be blocked. Furthermore, if the base concrete contains a large amount of gypsum with fairly high hydration reaction activity, the mixing water will be rapidly consumed, which will reduce the mixability of the quick-setting agent and make it difficult to obtain homogeneous shotcrete. On the other hand, if a large amount of gypsum that does not have high reaction activity is used, the setting retardation effect becomes prominent and rapid setting is inhibited, making it impossible to obtain high initial strength development.

特開2013-177279号公報Japanese Patent Application Publication No. 2013-177279 特開2002-053357号公報Japanese Patent Application Publication No. 2002-053357 特開2017-105672号公報JP 2017-105672 Publication

本発明の課題は、吹付施工、特に湿式吹付工法での施工に適した材齢28日圧縮強度が36N/mm2以上の高強度コンクリートであって、高い初期強度発現性と強力な付着性も具備し、例えば常温環境下で湿式吹付工法により施工しても施工装置(吹付装置)へのコンクリート固結による圧送、吹き付け障害も起こらず、安定した性状の吹付用高強度コンクリートを提供することにある。 The object of the present invention is to provide high-strength concrete with a 28-day compressive strength of 36 N/mm 2 or more that is suitable for spray construction, especially wet spray construction, and that also has high initial strength development and strong adhesion. In order to provide high-strength concrete for spraying that has stable properties and does not cause pressure feeding or spraying failure due to concrete consolidation to the construction equipment (spraying equipment) even if it is constructed using the wet spraying method in a normal temperature environment. be.

本発明者は、前記課題解決のため検討した結果、カルシウムアルミネート類を主成分とし、特定量のアルカリ金属の硫酸塩及び/又は炭酸塩と、特定の粉末度の石膏を含む急結材を、ポルトランドセメントと骨材と前記石膏よりも高い粉末度の石膏と水を含むベースコンクリートに加えた吹付用コンクリートが、初期~長期に至るまで高い強度発現性を具備でき、付着性にも優れ、例えば常温環境下で湿式吹付工法により施工しても、施工障害が極めて起こりにくいという知見を得、本発明を完成させた。 As a result of studies to solve the above-mentioned problems, the present inventor has developed a quick-setting material that contains calcium aluminates as the main component, a specific amount of alkali metal sulfate and/or carbonate, and gypsum of a specific powder level. , Shotcrete added to a base concrete containing portland cement, aggregate, gypsum with a higher degree of powder than the above-mentioned gypsum, and water can have high strength development from initial to long term, and has excellent adhesion. For example, the present invention was completed based on the knowledge that construction failure is extremely unlikely to occur even when construction is performed using a wet spraying method in an environment at room temperature.

即ち、本発明は、次の〔1〕~〔3〕の吹付用高強度コンクリートである。
〔1〕次のベースコンクリート(A)とベースコンクリート中のポルトランドセメント含有量100質量部に対し7~14質量部の急結材(B)からなる吹付用高強度コンクリート。
A;ポルトランドセメント100質量部、ブレーン比表面積8000~11000cm2/gの無水石膏7~16質量部、減水剤0.3~2質量部、骨材及び水を含有するベースコンクリート。
B;化学成分としてのCaOとAl23の含有モル比(CaO/Al23)が1.8~2.7のカルシウムアルミネートを68~87質量%、無水石膏10~26質量%、アルカリ金属の硫酸塩及び/又は炭酸塩3~12質量%を含有する急結材であって、急結材中の無水石膏が粉末度6600~8700cm2/gの石膏である急結材。
〔2〕急結材(B)がさらに硫酸アルミニウムを含有する前記〔1〕の吹付用高強度コンクリート。
〔3〕急結材(B)中のアルカリ金属硫酸塩(NS)とアルカリ金属炭酸塩(NC)との含有量が、(1)カルシウムアルミネート含有量が68質量%のときNS=0、NC=3~12質量%、(2)カルシウムアルミネート含有量が87質量%のときNC=0、NS=3~12質量%、(3)カルシウムアルミネート含有量が80質量%のときNS/NC=2:3~3:2、NS+NC=3~12質量%、(4)カルシウムアルミネート含有量が68質量%超80質量%未満のときカルシウムアルミネート含有量の増加に比例してNSは増加してNCは減少し、NS/NC=2:3~3:2になる、(5)カルシウムアルミネート含有量が80質量%超87質量%未満のときカルシウムアルミネート含有量の減少に比例してNCは増加してNSは減少し、NS/NC=2:3~3:2になる、前記〔1〕又は〔2〕記載の吹付用高強度コンクリート。
That is, the present invention is the following high-strength concrete for spraying [1] to [3].
[1] High-strength concrete for spraying consisting of the following base concrete (A) and 7 to 14 parts by mass of quick-setting agent (B) per 100 parts by mass of Portland cement in the base concrete.
A: Base concrete containing 100 parts by mass of Portland cement, 7 to 16 parts by mass of anhydrite with a Blaine specific surface area of 8000 to 11000 cm 2 /g, 0.3 to 2 parts by mass of a water reducing agent, aggregate and water.
B: Calcium aluminate with a molar ratio of CaO and Al 2 O 3 (CaO/Al 2 O 3 ) of 1.8 to 2.7 as chemical components, 68 to 87% by mass, anhydrite 10 to 26% by mass A quick-setting material containing 3 to 12% by mass of an alkali metal sulfate and/or carbonate, wherein the anhydrite in the quick-setting material is gypsum with a fineness of 6600 to 8700 cm 2 /g.
[2] The high-strength concrete for spraying according to [1] above, wherein the rapid setting agent (B) further contains aluminum sulfate.
[3] When the content of alkali metal sulfate (NS) and alkali metal carbonate (NC) in the rapid setting material (B) is (1) NS=0 when the calcium aluminate content is 68% by mass, NC = 3 to 12% by mass, (2) NC = 0 when the calcium aluminate content is 87% by mass, NS = 3 to 12% by mass, (3) NS / when the calcium aluminate content is 80% by mass. NC = 2:3 to 3:2, NS + NC = 3 to 12% by mass, (4) When the calcium aluminate content is more than 68% by mass and less than 80% by mass, NS increases in proportion to the increase in calcium aluminate content. (5) When the calcium aluminate content is more than 80% by mass and less than 87% by mass, the NC decreases and becomes NS/NC = 2:3 to 3:2, proportional to the decrease in the calcium aluminate content. The high-strength concrete for spraying according to [1] or [2] above, wherein NC increases and NS decreases, resulting in NS/NC = 2:3 to 3:2.

本発明によれば、次の(1)~(4)の効果が奏される。
(1)湿式吹付工法で施工した際に、水量や減水剤量を多くしなくとも、ベースコンクリートと急結材の混合性が良好なため、均質な性状の吹付コンクリートになる。
(2)吹付施工したコンクリートとしては材齢28日の圧縮強度が36N/mm2以上の安定した強度発現性の高強度のコンクリートを得ることができる。
(3)高い急結性と高い初期強度発現性も具備するため付着性に優れるものの、瞬結化による吹付装置への圧送障害や吹付障害は起き難い。
(4)アルカリ分が少ないため人体及び環境へのダメージリスクが軽減される。
According to the present invention, the following effects (1) to (4) are achieved.
(1) When performing construction using the wet spraying method, the mixability of the base concrete and quick-setting material is good, even without increasing the amount of water or water reducing agent, resulting in shotcrete with homogeneous properties.
(2) High-strength concrete with stable strength development and a compressive strength of 36 N/mm 2 or more after 28 days of age can be obtained as sprayed concrete.
(3) Although it has excellent adhesion because it has high rapid setting properties and high initial strength development properties, it is unlikely to cause trouble in pressure feeding to a spraying device or trouble in spraying due to instantaneous setting.
(4) Since the alkaline content is low, the risk of damage to the human body and the environment is reduced.

本発明の吹付用高強度コンクリートを構成する急結材(B)は、カルシウムアルミネートを主たる急結成分として含むものであり、他に少なくとも特定の粉末度の無水石膏と、アルカリ金属の硫酸塩及び/又は炭酸塩とを含む粉体状の急結材である。この急結材に使用するカルシウムアルミネートとは、CaOとAl23を主要化学成分とする無機水和活性物質であり、CaO源となる原料とAl23源となる原料を、化学成分としてのCaOとAl23の含有モル比(CaO/Al23)が1.8~2.7の加熱物(クリンカ)が得られるように配合した原料混合物を、好適には溶融するまで加熱することで得られる。好ましい含有モル比(CaO/Al23)は、2.0~2.6である。前記モル比が(CaO/Al23)が、1.8未満では、急結性が低くなることに加え、高い初期強度が得難くなるので好ましくない。前記モル比(CaO/Al23)が2.7を超えると、強い瞬結性が起こり易く、施工性が悪化するので好ましくない。また、本急結混和材に使用するカルシウムアルミネートには、その製造原料に例えば天然鉱物原料を用いたときのように、原料由来のCaOとAl23以外の不純物等の異成分も、その存在形態に拘わらず、本発明の効果を阻害させない範囲で含むことは可能である。 The quick-setting material (B) constituting the high-strength concrete for spraying of the present invention contains calcium aluminate as the main quick-setting component, and also contains at least anhydrite of a specific powder degree and an alkali metal sulfate. and/or carbonate. Calcium aluminate used in this quick-setting material is an inorganic hydration active material whose main chemical components are CaO and Al 2 O 3 . A raw material mixture blended so as to obtain a heated material (clinker) having a molar ratio of CaO and Al 2 O 3 (CaO/Al 2 O 3 ) of 1.8 to 2.7 is preferably melted. It can be obtained by heating until The preferred content molar ratio (CaO/Al 2 O 3 ) is 2.0 to 2.6. If the molar ratio (CaO/Al 2 O 3 ) is less than 1.8, it is not preferable because the rapid setting property becomes low and it becomes difficult to obtain high initial strength. If the molar ratio (CaO/Al 2 O 3 ) exceeds 2.7, strong instant setting tends to occur and workability deteriorates, which is not preferable. In addition, the calcium aluminate used in this rapid setting admixture may contain foreign components such as impurities other than CaO and Al 2 O 3 derived from the raw materials, such as when natural mineral raw materials are used as raw materials for its production. Regardless of the form in which it exists, it is possible to include it as long as it does not impede the effects of the present invention.

また、製造時の加熱後の冷却過程の違いにより、冷却後のカルシウムアルミネートの構造状態に様々な差異が生じるため、冷却条件、例えば冷却速度に応じて、非晶質化の度合であるガラス化率を調整できる。一般にガラス化率が高いほど反応活性が高く、急結性も高まるため、本急結混和材に使用するカルシウムアルミネートは、限定されるものではないが、実質的に結晶質のカルシウムアルミネートよりもガラス化が進んだカルシウムアルミネートを使用するのが良い。好ましくは、ガラス化率が60%以上のカルシウムアルミネートを使用する。最も好ましくは、ガラス化率が概ね95%以上のカルシウムアルミネートである。カルシウムアルミネートの粉末度は特に制限されない。好ましくは、コンリートへの急結材に使用したときに適度な反応活性が得易いことから、混和対象となる水硬性組成物中のセメントと同程度かそれ以上の粉末度とする。より好ましくは、粉末度としてブレーン比表面積3000~6000cm2/gである。 In addition, due to differences in the cooling process after heating during manufacturing, various differences occur in the structural state of calcium aluminate after cooling. You can adjust the conversion rate. In general, the higher the vitrification rate, the higher the reaction activity and the higher the rapid setting property. Therefore, the calcium aluminate used in this rapid setting admixture is, although not limited to, substantially higher than the crystalline calcium aluminate. It is also best to use calcium aluminate, which has been highly vitrified. Preferably, calcium aluminate with a vitrification rate of 60% or more is used. Most preferred is calcium aluminate with a vitrification rate of approximately 95% or more. The fineness of calcium aluminate is not particularly limited. Preferably, the fineness is equal to or higher than that of the cement in the hydraulic composition to be mixed, since it is easy to obtain a suitable reaction activity when used as a quick-setting agent for concrete. More preferably, the Blaine specific surface area in terms of fineness is 3000 to 6000 cm 2 /g.

本発明における急結材(B)には、このようなカルシウムアルミネートを68~87質量%含むものである。急結混和材中のカルシウムアルミネート含有量が68質量%未満では、急結性が不足し、吹付コンクリートに混和したときの付着性が劣るので好ましくない。また、87質量%を超える含有では、瞬結化が強く現れて吹付コンクリートの圧送障害や吹付障害が生じたり、硬化性が減退することもあるので好ましくない。好ましいカルシウムアルミネートの含有量は69~85質量%であり、より好ましくは69~84質量%である。 The rapid setting material (B) in the present invention contains 68 to 87% by mass of such calcium aluminate. If the content of calcium aluminate in the quick-setting admixture is less than 68% by mass, the quick-setting properties will be insufficient and the adhesion will be poor when mixed with shotcrete, which is not preferable. Moreover, if the content exceeds 87% by mass, instantaneous setting may occur strongly, causing trouble in the pumping or spraying of shotcrete, and hardening properties may deteriorate, which is not preferable. The preferred content of calcium aluminate is 69 to 85% by mass, more preferably 69 to 84% by mass.

本発明における急結材(B)には、特定の粉末度の無水石膏を含有する。使用する無水石膏は何れの結晶構造のものでも良い。無水石膏を含有することで、初期から長期にわたる全体的な強度の底上げと硬化性の促進がなされるのに寄与する。使用する無水石膏の粉末度はブレーン比表面積で6600~8700cm2/gとする。好ましい粉末度はブレーン比表面積で7000~8500cm2/gである。無水石膏の粉末度がブレーン比表面積で6600cm2/g未満では、反応活性が弱く、初期強度の底上げがなされ難いので好ましくなく、ブレーン比表面積で8700cm2/gを超えると、吸湿し易くなることに加え、粉体流動性が低下するため急結材が吹付装置へスムーズに流れず、供給量変動が起こる虞があるので好ましくない。また、急結材中の無水石膏含有量は、10~26質量%である。好ましくは12~22質量%であり、より好ましくは12~18質量%である。10質量%未満では、前記のような配合作用が十分得られないので好ましくなく、また26質量%を超えると、急結性が阻害されるので好ましくない。 The rapid setting material (B) in the present invention contains anhydrite of a specific powder degree. The anhydrite used may have any crystal structure. Containing anhydrite contributes to raising the overall strength from the initial stage to the long term and promoting hardening. The powder degree of the anhydrite used is 6600 to 8700 cm 2 /g in Blaine specific surface area. The preferred fineness is 7,000 to 8,500 cm 2 /g in Blaine specific surface area. If the powderiness of anhydrite is less than 6,600 cm 2 /g in Blaine specific surface area, the reaction activity is weak and it is difficult to raise the initial strength, which is undesirable. If it exceeds 8,700 cm 2 /g in Blaine specific surface area, it becomes easy to absorb moisture. In addition, powder flowability is reduced, so that the quick-setting material does not flow smoothly to the spraying device, which is undesirable because there is a possibility that the supply amount may fluctuate. Further, the anhydrite content in the quick-setting material is 10 to 26% by mass. It is preferably 12 to 22% by weight, more preferably 12 to 18% by weight. If it is less than 10% by mass, the above-mentioned blending effect cannot be obtained sufficiently, which is undesirable, and if it exceeds 26% by mass, rapid setting is inhibited, which is not preferred.

本発明における急結材(B)には、アルカリ金属の硫酸塩及び/又は炭酸塩を含有する。アルカリ金属としては、リチウム、カリウム、ナトリウムを挙げることができる。コスト的な観点からナトリウムが推奨される。アルカリ金属の硫酸塩やアルカリ金属の炭酸塩は、何れも無水物の使用が望ましい。アルカリ金属の硫酸塩は凝結促進に寄与し、アルカリ金属の炭酸塩は特に初期における強い硬化促進作用を付与する。アルカリ金属の硫酸塩とアルカリ金属の炭酸塩の急結材中の含有量は、何れか一方しか含まない場合や両者とも含む場合であっても、無水物換算で、3~12質量%とする。好ましくは4~12質量%であり、より好ましくは4~11質量%であり、さらに好ましくは、両者を併用し、それぞれ2~6質量%ずつ含有する場合である。急結材中のアルカリ金属の炭酸塩と硫酸塩(炭酸塩か硫酸塩の何れか1種しか含まないときはその1種の量、両方含むときはその合計量)の含有量が3質量%未満では配合効果が殆ど得られないので好ましくなく、12質量%を超えると急結性又は強度発現性を阻害する虞があるので好ましくない。 The rapid setting material (B) in the present invention contains an alkali metal sulfate and/or carbonate. Examples of alkali metals include lithium, potassium, and sodium. Sodium is recommended from a cost standpoint. It is desirable to use anhydrous forms of alkali metal sulfates and alkali metal carbonates. The alkali metal sulfate contributes to accelerating setting, and the alkali metal carbonate has a strong effect of accelerating hardening, especially in the initial stage. The content of alkali metal sulfate and alkali metal carbonate in the quick-setting agent should be 3 to 12% by mass in terms of anhydride, even if it contains only one or both. . Preferably it is 4 to 12% by mass, more preferably 4 to 11% by mass, and even more preferably both are used together and each content is 2 to 6% by mass. The content of alkali metal carbonate and sulfate in the quick-setting material is 3% by mass (if only one type of carbonate or sulfate is contained, the amount of the other type, and if both are contained, the total amount) is 3% by mass. If it is less than 12% by mass, it is not preferable because almost no blending effect can be obtained, and if it exceeds 12% by mass, it is not preferable because there is a possibility that rapid setting or strength development may be inhibited.

最も好ましくは、カルシウムアルミネートの含有量に連動して、アルカリ金属硫酸塩(NS)とアルカリ金属炭酸塩(NC)の合計含有量は前記範囲としつつ、両者の含有量を次の関係になるように変動させた量にすることである。すなわち、急結材(B)中のアルカリ金属硫酸塩(NS)とアルカリ金属炭酸塩(NC)との含有量が、(1)カルシウムアルミネート含有量が68質量%のときNS=0、NC=3~12質量%;(2)カルシウムアルミネート含有量が87質量%のときNC=0、NS=3~12質量%;(3)カルシウムアルミネート含有量が80質量%のときNS/NC=2:3~3:2、NS+NC=3~12質量%;(4)カルシウムアルミネート含有量が68質量%超80質量%未満のときカルシウムアルミネート含有量の増加に比例してNSは増加してNCは減少し、最終的にNS/NC=2:3~3:2になる;(5)カルシウムアルミネート含有量が80質量%超87質量%未満のときカルシウムアルミネート含有量の減少に比例してNCは増加してNSは減少し、最終的にNS/NC=2:3~3:2になる。
さらに好ましい一例としては、急結材(B)中のアルカリ金属硫酸塩の含有量をSy質量%、アルカリ金属炭酸塩の含有量をCy質量%、及びカルシウムアルミネート含有量をAx質量%(質量は何れも無水物換算)とすると、
Most preferably, in conjunction with the content of calcium aluminate, the total content of alkali metal sulfate (NS) and alkali metal carbonate (NC) is within the above range, and the content of both is in the following relationship. The idea is to make the amount fluctuate as follows. That is, the content of alkali metal sulfate (NS) and alkali metal carbonate (NC) in the rapid setting material (B) is (1) when the calcium aluminate content is 68% by mass, NS = 0, NC = 3 to 12% by mass; (2) NC = 0 when the calcium aluminate content is 87% by mass, NS = 3 to 12% by mass; (3) NS/NC when the calcium aluminate content is 80% by mass = 2:3 to 3:2, NS + NC = 3 to 12% by mass; (4) When the calcium aluminate content is more than 68% by mass and less than 80% by mass, NS increases in proportion to the increase in calcium aluminate content. and NC decreases, finally becoming NS/NC = 2:3 to 3:2; (5) When the calcium aluminate content is more than 80% by mass and less than 87% by mass, the calcium aluminate content decreases. NC increases and NS decreases in proportion to, and finally NS/NC=2:3 to 3:2.
As a more preferable example, the content of alkali metal sulfate in the rapid setting material (B) is Sy mass %, the content of alkali metal carbonate is Cy mass %, and the calcium aluminate content is Ax mass % (mass (both are anhydrous equivalent), then

(数1)
3≦Sy+Cy≦12、68≦Ax≦87、及びSy+Cy+Ax≦90を前提条件とし、
Ax=68のときに、Sy=0、3≦Cy≦12;
68<Ax<80のときに、2・Cy・(Ax-68)/27<Sy<Cy・(Ax-68)/6;
Ax=80のときに、2/3≦Sy/Cy≦3/2;
80<Ax<87のときに、Sy・(174-2・Ax)/21<Cy<Sy・3・(87-Ax)/14;
Ax=87のときに、Cy=0、Sy=3。
(Number 1)
Assuming that 3≦Sy+Cy≦12, 68≦Ax≦87, and Sy+Cy+Ax≦90,
When Ax=68, Sy=0, 3≦Cy≦12;
When 68<Ax<80, 2・Cy・(Ax-68)/27<Sy<Cy・(Ax-68)/6;
When Ax=80, 2/3≦Sy/Cy≦3/2;
When 80<Ax<87, Sy・(174-2・Ax)/21<Cy<Sy・3・(87-Ax)/14;
When Ax=87, Cy=0, Sy=3.

以上の関係を総じて満たすアルカリ金属炭酸塩とアルカリ金属硫酸塩の含有量にする。この条件を満たすと、施工障害となりうるような瞬結化を避けつつ高い初期強度と高い付着性が特にバランス良く発現できる。 The content of alkali metal carbonate and alkali metal sulfate should be determined so as to satisfy the above relationship as a whole. When this condition is met, high initial strength and high adhesion can be achieved in a particularly well-balanced manner while avoiding instantaneous setting, which can be a hindrance to construction.

本発明における急結材(B)には、さらに硫酸アルミニウムを含有することができる。硫酸アルミニウムは、何れの硫酸アルミニウムでも良く、例えば16水和物でも、無水物でも使用できる。好ましくは性状安定性が高いことから硫酸アルミニウム16水和物の使用が推奨される。アルミニウムの硫酸塩の含有は、急結助剤として急結性付与に寄与し、特に凝結開始時間をより促進する作用を呈する。急結材中の硫酸アルミニウムの含有量は限定されるものではないが、含有する場合は、無水物換算で2~5質量%が好ましい。 The rapid setting material (B) in the present invention can further contain aluminum sulfate. The aluminum sulfate may be any aluminum sulfate, for example, a hexahydrate or an anhydride. Preferably, it is recommended to use aluminum sulfate hexahydrate because of its high property stability. The inclusion of aluminum sulfate contributes to imparting rapid setting properties as a rapid setting aid, and particularly has the effect of further accelerating the setting start time. The content of aluminum sulfate in the rapid setting material is not limited, but if it is contained, it is preferably 2 to 5% by mass in terms of anhydride.

本発明における急結材(B)には、前記以外の成分も本発明の効果を阻害しない範囲で含有することができる。また、本発明の急結材は、粒度は特に制限されず、粉末や顆粒状であれば良い。望ましくは、風化し易くなく、良好な急結性や強度発現性が得られることから、ブレーン比表面積で概ね3000~6500cm2/gで最大粒径が約1mm以下の粉体とするのが良い。 The quick-setting material (B) in the present invention may also contain components other than those mentioned above within a range that does not impede the effects of the present invention. Further, the particle size of the rapid setting material of the present invention is not particularly limited, and may be in the form of powder or granules. Desirably, the powder should have a Blaine specific surface area of approximately 3000 to 6500 cm 2 /g and a maximum particle size of approximately 1 mm or less, since it is not easily weathered and provides good rapid setting and strength development properties. .

また、本発明の吹付用高強度コンクリートを構成するベースコンクリート(A)は、ポルトランドセメントを主たる結合相形成成分とし、他に少なくとも骨材と特定の粉末度の無水石膏と高性能減水剤及び水を含有する。使用するポルトランドセメントは何れのものでも良く、具体的には、普通、早強、超早強、中庸熱、低熱、耐硫酸塩等のポルトランドセメントの少なくとも何れか1種以上とする。ポルトランドセメントの粉末度は特に制限されるものではない。好ましくは、水和反応活性と経済性の観点からブレーン比表面積約2500~4500cm2/gが適当である。また、ポルトランドセメントの一部を他の水硬性無機物質、例えば高炉スラグ微粉など、と置換することは、本発明の効果を阻害しない範囲で許容されるが、極力ポルトランドセメントのみを使用するのが望ましい。尚、一般に、ポルトランドセメントには少量の石膏類が含まれるが、本発明では成分含有量に関し、ポルトランドセメント中にもともと含まれる石膏類は、ベースコンクリート形成のために配合含有される無水石膏として考慮せずに、ポルトランドセメントそのものの一部分として扱う。 The base concrete (A) constituting the high-strength concrete for spraying of the present invention has Portland cement as the main binder phase forming component, and also includes at least aggregate, anhydrite of a specific powder, a high-performance water reducer, and water. Contains. Any type of Portland cement may be used, and specifically, at least one type of Portland cement such as normal, early strength, super early strength, medium heat, low heat, and sulfate resistant Portland cement is used. The fineness of Portland cement is not particularly limited. Preferably, from the viewpoint of hydration reaction activity and economic efficiency, a Blaine specific surface area of about 2,500 to 4,500 cm 2 /g is appropriate. In addition, it is permissible to replace a portion of Portland cement with other hydraulic inorganic substances, such as blast furnace slag powder, as long as it does not impede the effects of the present invention, but it is preferable to use only Portland cement as much as possible. desirable. Generally, Portland cement contains a small amount of gypsum, but in the present invention, regarding the component content, the gypsum originally contained in Portland cement is considered as anhydrous gypsum that is mixed and contained to form the base concrete. Instead, it is treated as a part of Portland cement itself.

また、本発明における前記ベースコンクリート(A)に含まれる骨材は、コンクリートに使用できる細骨材と粗骨材であれば何れのものでも良く、その両者を含有する。好ましくは、細骨材及び粗骨材とも、所定の骨材強度が確保し易く、他の含有成分との密度差が少ないため材料分離が起き難いことから、表乾密度が2.3~2.9g/cmの骨材を使用する。このような骨材としては、例えば、細骨材として珪砂や石灰石砂等の天然骨材、安山岩、砂岩、玄武岩等の砕砂などを挙げることができる。また、粗骨材としては珪石、石灰石、安山岩、砂岩、玄武岩等の砕石や砂利を挙げることができる。ベースコンクリート(A)中の骨材含有量は特に制限されない。好ましくは、ポルトランドセメント含有量100質量部に対する粗骨材と細骨材の合計含有量が150~800質量部とする。より好ましくは、ポルトランドセメント含有量100質量部に対し、粗骨材120~160質量部、細骨材180~260質量部である。 Further, the aggregate contained in the base concrete (A) in the present invention may be any fine aggregate or coarse aggregate that can be used in concrete, and contains both of them. Preferably, both the fine aggregate and the coarse aggregate have a surface dry density of 2.3 to 2, because it is easy to ensure a predetermined aggregate strength and there is little difference in density from other contained components, making it difficult for material separation to occur. .9g/ cm3 aggregate is used. Examples of such aggregates include natural aggregates such as silica sand and limestone sand as fine aggregates, and crushed sands such as andesite, sandstone, and basalt. In addition, examples of the coarse aggregate include crushed stones such as silica stone, limestone, andesite, sandstone, and basalt, and gravel. The aggregate content in the base concrete (A) is not particularly limited. Preferably, the total content of coarse aggregate and fine aggregate is 150 to 800 parts by mass based on 100 parts by mass of Portland cement. More preferably, the amount of coarse aggregate is 120 to 160 parts by mass and the fine aggregate is 180 to 260 parts by mass per 100 parts by mass of Portland cement.

また、本発明における前記ベースコンクリート(A)に含まれる減水剤は、モルタルやコンクリートに使用できるものであって、高性能減水剤、高性能AE減水剤、分散剤、流動化剤等と称されている減水剤類も該当する。その有効成分は限定されず、状態も液体や粒状の何れでも良い。減水剤を配合含有することで、強度低下に繋がる水量増加をしなくとも、良好な圧送性や混合性確保が行える。ベースコンクリート(B)におけるポルトランドセメント含有量100質量部に対する減水剤の含有量は、固形分換算で、0.3~2質量部である。好ましくは、0.4~1.8質量部である。0.3質量部未満では、水量を増やさないと圧送性や混合性が悪化するので好ましくない。また2質量部を超えると、凝結が遅延し、付着性が低下するので好ましくない。 Furthermore, the water reducer contained in the base concrete (A) in the present invention can be used for mortar and concrete, and is referred to as a high performance water reducer, a high performance AE water reducer, a dispersant, a fluidizing agent, etc. This also applies to water reducing agents. The active ingredient is not limited, and the state may be either liquid or granular. By incorporating a water reducing agent, it is possible to ensure good pumpability and mixability without increasing the amount of water that would lead to a decrease in strength. The content of the water reducing agent per 100 parts by mass of Portland cement in the base concrete (B) is 0.3 to 2 parts by mass in terms of solid content. Preferably, it is 0.4 to 1.8 parts by mass. If the amount is less than 0.3 parts by mass, the pumpability and mixing properties will deteriorate unless the amount of water is increased, which is not preferable. Moreover, if it exceeds 2 parts by mass, coagulation will be delayed and adhesion will be reduced, which is not preferable.

また、本発明における前記ベースコンクリート(A)に含まれる無水石膏は、粉末度がブレーン比表面積8000~11000cm2/gの無水石膏を使用する。好ましくはブレーン比表面積9000~10500cm2/gの無水石膏を使用する。このような粉末度の無水石膏を含有することで、反応活性が高い石膏がセメントと水和反応し、高強度なエトリンガイト相の生成が促進される、初期から長期にわたる強度の底上げがなされるため高い強度発現性が得られる。無水石膏のブレーン比表面積が8000cm2/g未満では、反応活性が不足し、主に初期における硬化性が十分向上せず、高い強度発現性が得難くなるので好ましくない。また、無水石膏のブレーン比表面積が11000cm2/gを超えると、反応活性が高過ぎるため、注水後のコンクリート中で、無水石膏と水との反応が優先的に進み易く、セメントの水和反応が支障をきたし、エトリンガイトが効率良く生成され難くなるので好ましくない。前記粉末度の無水石膏のベースコンクリート中の含有量は、セメント含有量100質量部に対し、7~16質量部とする。好ましくは、8~12質量部である。セメント含有量100質量部に対する無水石膏含有量が7質量部未満では、エトリンガイト相生成が促進され難くなって、全体的な強度の底上げが十分できないことがあるので好ましくなく、16質量部を超える含有量では凝結遅延やコンクリート施工物が過膨張を起こす虞もあるので好ましくない。 Further, as the anhydrite contained in the base concrete (A) in the present invention, anhydrite having a powder degree of Blaine specific surface area of 8,000 to 11,000 cm 2 /g is used. Preferably, anhydrite having a Blaine specific surface area of 9,000 to 10,500 cm 2 /g is used. By containing such powdery anhydrite, the highly reactive gypsum undergoes a hydration reaction with cement, promoting the formation of a high-strength ettringite phase, increasing the strength from the initial stage to the long-term. High strength development can be obtained. If the Blaine specific surface area of the anhydrite is less than 8000 cm 2 /g, the reaction activity will be insufficient, mainly the initial curing property will not be sufficiently improved, and it will be difficult to obtain high strength development, which is not preferable. Furthermore, if the Blaine specific surface area of anhydrite exceeds 11,000 cm 2 /g, the reaction activity is too high, and the reaction between anhydrite and water tends to proceed preferentially in the concrete after water injection, resulting in a hydration reaction of cement. This is not preferable because it causes problems and makes it difficult for ettringite to be efficiently produced. The content of the powdery anhydrite in the base concrete is 7 to 16 parts by mass based on 100 parts by mass of cement. Preferably, it is 8 to 12 parts by mass. If the anhydrite content is less than 7 parts by mass with respect to 100 parts by mass of cement, ettringite phase formation will be difficult to promote, and the overall strength may not be raised sufficiently, so it is not preferable, and if the content exceeds 16 parts by mass. The amount is not preferable because it may cause a delay in setting or over-expansion of the concrete work.

また、本発明における前記ベースコンクリート(A)に含まれる水量は、特に限定されるものではないが、ポルトランドセメントセメント含有量100質量部に対し、施工障害や高い強度発現性が得難くなるリスクを避ける上では、概ね45~55質量部が望ましい。 In addition, the amount of water contained in the base concrete (A) in the present invention is not particularly limited; In order to avoid this, approximately 45 to 55 parts by mass is desirable.

また、本発明におけるベースコンクリート(A)は、前記以外の成分も本発明の効果を実質喪失させないものであれば含有することができる。例えば、カルシウムアルミネートや硫酸アルミニウム等の急結成分は、施工阻害要因となるので極力ベースコンクリートに含まれないことが望ましい。また、含有できるような成分を例示すると、何れもモルタルやコンクリートに用いることのできる、増粘剤、保水剤、短繊維、ポゾラン反応性物質、乾燥収縮低減剤等が挙げられるが、記載例に限定されるものではない。 Furthermore, the base concrete (A) in the present invention may also contain components other than those mentioned above, as long as the effects of the present invention are not substantially lost. For example, it is desirable that rapidly forming components such as calcium aluminate and aluminum sulfate are not included in the base concrete as much as possible, as they can hinder construction. In addition, examples of components that can be included include thickeners, water retention agents, short fibers, pozzolan reactive substances, drying shrinkage reducing agents, etc., all of which can be used in mortar and concrete. It is not limited.

本発明の吹付用高強度コンクリートは、前記ベースコンクリート(A)と、ベースコンクリート中のポルトランドセメント含有量100質量部に対し7~14質量部(無水物換算)の前記急結材(B)とからなる。好ましくは、9~12質量部(無水物換算)の急結材(B)とからなる。ベースコンクリート中のポルトランドセメント含有量100質量部に対し、7質量部未満の急結材の配合では、所望の急結性と特に初期に於ける高強度が得られないことがあるので好ましくなく、また14質量部を超える急結材の配合では、瞬結性が強くなり施工障害を起こす虞があるので好ましくない。 The high-strength concrete for spraying of the present invention comprises the base concrete (A) and the rapid setting agent (B) in an amount of 7 to 14 parts by mass (calculated as anhydride) based on 100 parts by mass of Portland cement in the base concrete. Consisting of Preferably, it comprises 9 to 12 parts by mass (calculated as anhydride) of the quick-setting agent (B). It is not preferable to mix less than 7 parts by mass of the rapid setting agent with respect to 100 parts by mass of Portland cement in the base concrete, as the desired rapid setting property and especially high strength in the initial stage may not be obtained. Further, if the rapid setting agent is added in an amount exceeding 14 parts by mass, the instant setting property becomes strong and there is a possibility that construction failure may occur, which is not preferable.

本発明の吹付用高強度コンクリートの製造方法の具体的な推奨例(以下に記載の推奨例に限定されるものではない。)を示すと、例えば二軸強制コンクリートミキサ等の混練可能な混合機を使用し、前記の如くベースコンクリート(A)の成分含有配合に基づいた量の成分(水を含む)を一括投入し、概ね1乃至2mあたりの混練時間を60~90秒程度として混練することでベースコンクリート(A)を得る。また、例えばヘンシェルミキサ等を使用し、前記の如く急結材(B)の成分含有配合に基づいた量の成分を一括投入し、概ね1分程度混合することで急結材(B)を得る。ベースコンクリート(A)を吹付装置にポンプ圧送し、圧送中のベースコンクリートに対し、Y字管やト字管等の三方管を用いて前記所定量の急結材(B)を添加する。添加後は吹付装置内移動中に混合が進み、吹付用高強度コンクリートが形成される。この吹付用高強度コンクリートを吹付装置のノズル孔から噴射し、対象物に吹き付ける。 Specific recommended examples (not limited to the recommended examples described below) of the method for producing high-strength concrete for spraying of the present invention include, for example, a mixer capable of kneading, such as a biaxial forced concrete mixer. As mentioned above, the ingredients (including water) in the amount based on the ingredient composition of base concrete (A) are added all at once, and kneaded for approximately 60 to 90 seconds per 1 to 2 m3 . By doing this, base concrete (A) is obtained. Alternatively, using a Henschel mixer or the like, add the ingredients in an amount based on the component composition of the quick-setting material (B) as described above at once, and mix for about 1 minute to obtain the quick-setting material (B). . The base concrete (A) is pumped to a spraying device, and the predetermined amount of the quick setting material (B) is added to the base concrete being pumped using a three-way pipe such as a Y-shaped pipe or a T-shaped pipe. After addition, mixing progresses while moving through the spraying equipment, forming high-strength concrete for spraying. This high-strength concrete for spraying is injected from the nozzle hole of the spraying device and sprayed onto the object.

以下、本発明を実施例によって具体的に説明するが、本発明は記載した実施例に限定されるものではない。尚、実施例は、特記無い限り、20±1℃の環境下で行った。 EXAMPLES Hereinafter, the present invention will be specifically explained with reference to examples, but the present invention is not limited to the described examples. Note that the Examples were conducted in an environment of 20±1° C. unless otherwise specified.

[カルシウムアルミネートの作製]
市販の工業用薬品のCaCO3とAl23を用い、CaO及びAl23の含有モル比(CaO/Al23)の値が表1に示すカルシウムアルミネートが得られるように秤量配合し、ヘンシェル型混合機で原料調合物を作製した。この原料調合物を電気炉中で、約1600℃±50℃にて60分間加熱した。一部のものを除き、前記加熱時間経過後は加熱物を直ちに炉外に取り出した。取り出した加熱物の表面に冷却用の窒素ガスを最大流速約30mL/秒で吹付けて急冷し、擬塊状の冷却物を得た。尚、冷却物のガラス化率については、窒素ガスの流速を調整する、具体的には前記最大流速よりも下げた値に調整する、ことで所望のガラス化率に調整した。前記最大流速の冷却用ガス吹付で得られた冷却物が、ガラス化率が概ね99%を超える実質的に非晶質のカルシウムアルミネート冷却物であることを確認し、他にガラス化率約95%及びガラス化率約60%のカルシウムアルミネートの冷却物も作製した。各冷却物は、全鋼製のボールミルで粉砕し、分級装置にかけてブレーン比表面積約5400cm2/gに整粒した。整粒粉末として、表1に表すガラス化率と、CaO及びAl23の含有モル比(CaO/Al23)のカルシウムアルミネート粉末を得た。得られたカルシウムアルミネート粉末は吸湿が進んでいない無含水の粉末であるため、配合使用時まで密封容器で保管した。尚、カルシウムアルミネートのガラス化率は、粉末エックス線回折装置を用い、質量がM1のカルシウムアルミネートクリンカに含まれる各鉱物の質量を内部標準法等で定量し、定量できた含有鉱物相の総和質量;M2を算出し、残部が純ガラス相と見なし、次式でガラス化率を算出した。
[Preparation of calcium aluminate]
Commercially available industrial chemicals CaCO 3 and Al 2 O 3 were weighed to obtain calcium aluminate with a molar ratio of CaO and Al 2 O 3 (CaO/Al 2 O 3 ) shown in Table 1. A raw material mixture was prepared using a Henschel type mixer. This raw material mixture was heated in an electric furnace at about 1600°C±50°C for 60 minutes. Except for some items, the heated items were immediately taken out of the furnace after the heating time had elapsed. Nitrogen gas for cooling was sprayed onto the surface of the heated material taken out at a maximum flow rate of about 30 mL/sec to rapidly cool it, thereby obtaining a pseudo-massive cooled material. The vitrification rate of the cooled material was adjusted to a desired vitrification rate by adjusting the flow rate of nitrogen gas, specifically by adjusting it to a value lower than the maximum flow rate. It was confirmed that the cooled material obtained by blowing the cooling gas at the maximum flow rate was a substantially amorphous calcium aluminate cooled material with a vitrification rate of about 99%. A calcium aluminate coolant with a vitrification rate of 95% and a vitrification rate of about 60% was also produced. Each cooled material was pulverized in an all-steel ball mill, and sized to have a Blaine specific surface area of about 5400 cm 2 /g using a classifier. Calcium aluminate powder having a vitrification rate and a molar ratio of CaO and Al 2 O 3 (CaO/Al 2 O 3 ) shown in Table 1 was obtained as a sized powder. Since the obtained calcium aluminate powder was a water-free powder with no progress in moisture absorption, it was stored in a sealed container until blended and used. The vitrification rate of calcium aluminate is calculated by using a powder X-ray diffractometer to quantify the mass of each mineral contained in the calcium aluminate clinker with a mass of M1 using an internal standard method, etc. Mass; M2 was calculated, and the remainder was considered to be a pure glass phase, and the vitrification rate was calculated using the following formula.

(数2)
ガラス化率(%)=(1-M2/M1)×100
(Number 2)
Vitrification rate (%) = (1-M2/M1) x 100

Figure 0007351660000001
Figure 0007351660000001

[急結材の作製]
前記作製の表1に表すカルシウムアルミネート粉末と以下の使用材料とから選定された材料を、無水物換算で表2の配合割合になるよう秤量してヘンシェルミキサに一括投入した。このミキサで約2分間混合し、粉体状の急結性混和剤を作製した。作製した急結性混和剤は後述するベースコンクリートに添加使用するまで密封容器中で保管した。尚、無水石膏は市販のII型無水石膏を粉砕・分級処理することにより所定の粉末度に整えた。また、表2中の配合材料名は、次の略号を用いて記す。
[Preparation of quick-setting material]
Materials selected from the calcium aluminate powder shown in Table 1 of the above production and the materials used below were weighed so as to have the blending ratio shown in Table 2 in terms of anhydride, and were charged all at once into a Henschel mixer. The mixture was mixed for about 2 minutes using this mixer to produce a powdered rapid-setting admixture. The prepared quick-setting admixture was stored in a sealed container until it was added to the base concrete described below. The anhydrite was prepared to a predetermined powder level by crushing and classifying commercially available type II anhydrite. In addition, the names of compounded materials in Table 2 are written using the following abbreviations.

[急結材作製のための使用材料(カルシウムアルミネートを除く)]
CS-A;無水石膏A(ブレーン比表面積;6600cm2/g)
CS-B;無水石膏B(ブレーン比表面積;7600cm2/g)
CS-C;無水石膏C(ブレーン比表面積;8700cm2/g)
CS-D;無水石膏D(ブレーン比表面積;10500cm2/g)
NS;無水中性芒硝(ブレーン比表面積;5000cm2/g、市販工業用薬品)
NC;炭酸ナトリウム(市販粉末試薬)
LC;炭酸リチウム(市販粉末試薬)
SA;硫酸アルミニウム・16水和物(市販粉末試薬)
[Materials used for producing quick-setting material (excluding calcium aluminate)]
CS-A; Anhydrite A (Brain specific surface area; 6600 cm 2 /g)
CS-B; Anhydrite B (Brain specific surface area; 7600 cm 2 /g)
CS-C; Anhydrite C (Brain specific surface area; 8700cm 2 /g)
CS-D; Anhydrite D (Brain specific surface area; 10500 cm 2 /g)
NS: Anhydrous Glauber's Salt (Blaine specific surface area: 5000 cm 2 /g, commercially available industrial chemical)
NC: Sodium carbonate (commercially available powder reagent)
LC: Lithium carbonate (commercially available powder reagent)
SA; Aluminum sulfate hexahydrate (commercially available powder reagent)

Figure 0007351660000002
Figure 0007351660000002

[ベースコンクリートの作製]
次に表す使用材料と水から選定される材料を、表3で表す配合となるよう強制二軸ミキサ(回転数62rpm)に投入し、約90秒混練することで、約1m3のベースコンクリートを作製した。尚、使用材料のII型無水石膏は市販品を粉砕・分級処理により所定粒度に整えた。
[Preparation of base concrete]
The materials selected from the following materials and water are put into a forced twin-screw mixer (rotation speed: 62 rpm) so as to have the composition shown in Table 3, and mixed for about 90 seconds to create about 1 m 3 of base concrete. Created. The type II anhydrite used as a material was a commercially available product that was pulverized and classified to a predetermined particle size.

[ベースコンクリート作製の使用材料]
OPC;普通ポルトランドセメント(ブレーン比表面積3160cm2/g)
CS-F;無水石膏(ブレーン比表面積9000cm2/g)
CS-E;無水石膏(ブレーン比表面積9800cm2/g)
CS-D;無水石膏(ブレーン比表面積10500cm2/g)
CS-G;無水石膏(ブレーン比表面積14000cm2/g)
SG;普通細骨材(掛川産陸砂、F.M.=2.7、表乾密度2.56g/cm3
G1;普通粗骨材(砂岩砕石、最大粒径15mm、表乾密度2.74g/cm3
TS;ポリカルボン酸系高性能減水剤(濃度23%液状、市販品、表3及び5記載の配合量は固形分換算量)
[Materials used for base concrete production]
OPC: Ordinary Portland cement (Brain specific surface area 3160cm 2 /g)
CS-F; Anhydrite (Brain specific surface area 9000cm 2 /g)
CS-E; Anhydrite (Brain specific surface area 9800cm 2 /g)
CS-D; Anhydrite (Brain specific surface area 10,500 cm 2 /g)
CS-G; Anhydrite (Brain specific surface area 14000cm 2 /g)
SG: Ordinary fine aggregate (land sand from Kakegawa, FM=2.7, surface dry density 2.56g/cm 3 )
G1: Ordinary coarse aggregate (crushed sandstone, maximum particle size 15 mm, surface dry density 2.74 g/cm 3 )
TS: Polycarboxylic acid-based high performance water reducing agent (concentration 23% liquid, commercially available product, amounts listed in Tables 3 and 5 are equivalent to solid content)

Figure 0007351660000003
Figure 0007351660000003

[吹付用コンクリートの作製]
表3で表した急結材を、無水物換算で表4に示す添加量になるよう前記作製のベースコンクリートに加え、以下の手順で吹付用コンクリートを作製した。即ち、前記のようにベースコンクリートを混合機で混練後、これを長さ約10m、内径6cmの樹脂製ホースを介して吹付装置へポンプ圧送した。使用した吹付装置は、ベースコンクリートを圧送する内径2インチの圧送管と、その側面に約30度の傾斜角で連通するベースコンクリートに急結材を供給添加するための円筒状側管と、吹付用コンクリートを吹き付ける内径(先端孔径)2インチの噴射用ノズルとを基本構成とした市販品である。ここで、前記急結材供給用の側管は、前記圧送管と噴射用ノズルとの間に鋼製ト字状管(三方管)を介すことで形成させた。即ち、ト字状管の直線上に位置する二方の管口に圧送管と噴射用ノズルがそれぞれ接続され、残りの管口に、別送される急結材の供給管(側管)が接続される構造とした。ト字状管内でのベースコンクリートへの急結材の添加位置(ベースコンクリートと急結材の合流地点)から噴射用ノズルまでの距離の間に、ベースコンクリートと急結材の混合がなされ、その距離(混合距離)は概ね1.5mとした。急結材は圧搾空気により所定量を空気圧送し、これを前記吹付装置内で圧送中のベースコンクリートに添加し、添加されたコンクリートは所定の混合距離を進む間に混合が進み、吹付用コンクリートが得られた。
[Preparation of shotcrete]
The rapid setting materials shown in Table 3 were added to the base concrete prepared above in amounts shown in Table 4 in terms of anhydride, and shotcrete concrete was prepared according to the following procedure. That is, after the base concrete was mixed in a mixer as described above, it was pumped to a spraying device via a resin hose with a length of about 10 m and an inner diameter of 6 cm. The spraying equipment used was a pressure feed pipe with an inner diameter of 2 inches for pumping the base concrete, a cylindrical side pipe connected to the side of the pipe at an angle of about 30 degrees for supplying and adding quick-setting material to the base concrete, and a spray pipe for feeding the base concrete. This is a commercially available product that basically consists of a 2-inch inner diameter (tip hole diameter) injection nozzle for spraying concrete. Here, the side pipe for supplying the quick setting material was formed by interposing a steel T-shaped pipe (three-way pipe) between the pressure feeding pipe and the injection nozzle. In other words, the pressure feed pipe and the injection nozzle are connected to two pipe ports located on a straight line of the T-shaped pipe, and the supply pipe (side pipe) for quick-setting material, which is sent separately, is connected to the remaining pipe port. The structure was designed to be The base concrete and the quick-setting material are mixed between the point where the quick-setting material is added to the base concrete in the T-shaped pipe (the meeting point of the base concrete and the quick-setting material) and the injection nozzle, and the The distance (mixing distance) was approximately 1.5 m. A predetermined amount of quick-setting material is pneumatically fed using compressed air, and this is added to the base concrete being pumped in the spraying device.The added concrete progresses in mixing as it travels a predetermined mixing distance, and becomes spray concrete. was gotten.

Figure 0007351660000004
Figure 0007351660000004

[急結性の評価]
表4のベースコンクリートの配合において、それぞれ含有する粗骨材と細骨材の合計含有量に相当する量を全て細骨材の含有量にし、粗骨材を含まず、また他の成分とその含有量は変更せずに表2のままとし、モルタル配合に変更したベースモルタルも、前記ベースコンクリートと同様の手順で作製した。前記ベースモルタルの配合は表5に示す。
[Evaluation of rapid setting]
In the base concrete formulation in Table 4, the content of fine aggregate is equal to the total content of coarse aggregate and fine aggregate, and no coarse aggregate is included, and other components and their A base mortar with the content unchanged as shown in Table 2 and a changed mortar composition was also produced in the same manner as the base concrete. The formulation of the base mortar is shown in Table 5.

Figure 0007351660000005
Figure 0007351660000005

得られたベースモルタルに前記急結材を、ベースモルタル中のポルトランドセメント含有量100質量部に対する添加量が、対応する表4に示すベースコンクリート中のポルトランドセメント100質量部あたりの急結材添加量と同一量となるように加え、高速ミキサで5秒間混合し、モルタル混練物を作製した。ベースモルタルへの具体的な添加量は表6に示す。 The above-mentioned quick setting agent is added to the obtained base mortar, and the amount added to 100 parts by mass of Portland cement in the base mortar is shown in Table 4.The amount of quick setting agent added per 100 parts by mass of Portland cement in the base concrete is shown in Table 4. and mixed in the same amount with a high-speed mixer for 5 seconds to prepare a mortar kneaded product. The specific amount added to the base mortar is shown in Table 6.

Figure 0007351660000006
Figure 0007351660000006

前記急結混和材添加から、30秒経過時、60秒経過時及び180秒経過時のモルタル混練物のプロクター貫入抵抗値を測定し、急結性を評価した。プロクター貫入抵抗の測定方法は、土木学会コンクリート標準示方書「吹付コンクリート用急結剤品質規格」附属書「急結剤を添加したモルタルの貫入抵抗による瞬結時間測定方法」に準拠し、断面積0.125cm2のプロクター針を使用した。この貫入抵抗値の測定結果も表7に示す。ここで、表中に記載した「×」は、モルタルの硬化が進み貫入抵抗の測定ができなかったことを表す。また、「>16(N/mm2)」なる記載はプロクター針の打込みはできたが、今回の使用機材の測定限界(最大16N/mm2)を超えたものである。 The proctor penetration resistance value of the mortar mixture was measured at 30 seconds, 60 seconds, and 180 seconds after the addition of the rapid setting admixture, and the rapid setting property was evaluated. The method for measuring Proctor penetration resistance is based on the Japan Society of Civil Engineers Standard Specifications for Concrete, "Quality Standards for Quick Setting Agents for Shotcrete," annex "Method for measuring instant setting time using penetration resistance of mortar added with quick setting agents," and A 0.125 cm 2 Proctor needle was used. The measurement results of this penetration resistance value are also shown in Table 7. Here, the "x" in the table indicates that the mortar had progressed to hardening and the penetration resistance could not be measured. In addition, the description ">16 (N/mm 2 )" means that the proctor needle could be inserted, but it exceeded the measurement limit (maximum 16 N/mm 2 ) of the equipment used this time.

Figure 0007351660000007
Figure 0007351660000007

[吹付コンクリートの付着性の評価]
前記の吹付装置を使用し、得られた吹付用コンクリートを直ちに吹付施工に供した。吹付施工は次のような対象物に向かって吹き付けた。即ち、前記吹付装置のノズル孔端から約100cm離れた地点に垂直に設置した厚さ9mmで3m四方のコンクリート製平板面に向かって、10m3/時間の流量で、前記吹付用コンクリートを吹き付けた。吹き付けたコンクリートの付着性の評価を、目視観察により次のように行った。即ち、前記平板面に吹き付けたコンクリートに垂れや剥落が起こることなく、付着し続けたものを付着性が「良好」と判断し、それ以外の状態になったものや瞬結等により吹き付け施工自体ができなかったものは、全て付着性が「不良」と判断した。結果を表8に示す。
[Evaluation of adhesion of shotcrete]
Using the above-mentioned spraying apparatus, the obtained shotcrete was immediately subjected to spraying construction. The spraying process was performed on the following objects: That is, the above-mentioned shotcrete was sprayed at a flow rate of 10 m 3 /hour toward the surface of a 3-m square concrete plate with a thickness of 9 mm that was installed vertically at a point approximately 100 cm away from the end of the nozzle hole of the above-mentioned spraying device. . The adhesion of the sprayed concrete was evaluated by visual observation as follows. In other words, if the concrete sprayed onto the flat plate surface continues to adhere without sagging or peeling, the adhesion is judged to be "good", and if the concrete is in any other condition or is caused by instantaneous setting, etc., the spraying construction itself is judged as All cases in which it was not possible to do so were judged to have "poor" adhesion. The results are shown in Table 8.

Figure 0007351660000008
Figure 0007351660000008

また、このような吹付を5分間行った後に、ベースコンクリートの圧送供給を30分間停止して吹付を中断した後、ベースコンクリートの圧送供給を再開し、再度吹付けを行った。その際、ト字管や吹付装置の圧送経路中に狭窄や閉塞等の圧送障害や、吹付用コンクリートの吹出量(噴射量)の明らかな低下や脈動などの吹付障害があったものを圧送性「不良」と判断した。また、これらの現象が見られず、スムーズに圧送でき、吹付量の変動や圧送時の脈動も見られなかったものは、圧送性「良好」と判断した。この結果も表8に示す。 Further, after such spraying was carried out for 5 minutes, the pressure supply of the base concrete was stopped for 30 minutes to interrupt the spraying, and then the pressure supply of the base concrete was restarted and spraying was performed again. At that time, if there is a pumping failure such as stenosis or blockage in the T-shaped pipe or the pumping route of the spraying device, or if there is a clear drop in the amount of sprayed concrete (injection amount) or pulsation, the pumping problem will be checked. It was judged as "defective". In addition, if these phenomena were not observed, the pumping could be carried out smoothly, and no fluctuations in the amount of spraying or pulsation during pumping were observed, the pumping performance was judged to be "good". The results are also shown in Table 8.

[吹付コンクリートの強度発現性の評価]
前記の如く作製した吹付用コンクリートを、作製後直ちに、内寸30×40×20cmの成形用型枠内に吹き付け、型枠内を満たすようにした。これを20℃(±1℃)恒温庫に入れ所定時間経過後、型枠内の硬化コンクリートからコアドリルによって直径5cm、高さ10cmの円柱状供試体を採取し、材齢24時間並びに28日にした供試体を得た。各材齢の供試体の一軸圧縮強度をアムスラー式圧縮強度試験機で測定した。また、土木学会規準JSCE-G561に規定するプルアウト試験用型枠と埋込具を使用し、前記と同様に作製した吹付用コンクリートを、JSCE-G561に準拠したプルアウト試験に供した。当該試験により材齢15分の吹付用コンクリートの圧縮強度を測定した。以上の各強度測定の結果を表8に示す。尚、所定材齢で未硬化のものや瞬結等により吹き付けができなかったものは、強度測定試験不能なため、表8の測定値の欄は「×」と表記した。
[Evaluation of strength development of shotcrete]
The shotcrete prepared as described above was immediately sprayed into a molding form having internal dimensions of 30 x 40 x 20 cm to fill the inside of the form. This was placed in a constant temperature warehouse at 20℃ (±1℃) and after a predetermined period of time, a cylindrical specimen with a diameter of 5cm and a height of 10cm was taken from the hardened concrete in the formwork using a core drill. A test specimen was obtained. The unconfined compressive strength of the specimens at each age was measured using an Amsler type compressive strength testing machine. In addition, shotcrete prepared in the same manner as above was subjected to a pull-out test in accordance with JSCE-G561 using a pull-out test form and embedding tool specified in the Japan Society of Civil Engineers standard JSCE-G561. Through this test, the compressive strength of shotcrete concrete with an age of 15 minutes was measured. Table 8 shows the results of each of the above strength measurements. In addition, since the strength measurement test cannot be performed on uncured materials at a predetermined age or those that could not be sprayed due to instantaneous setting, etc., the measured value column in Table 8 is marked with "x".

表7の結果から、本発明品の吹付コンクリートは、吹付施工時の付着性を十分確保するための高い急結性を具備することがわかる。一方で、表8の結果から急結剤の添加前後ともスムーズな圧送に適したコンクリートの流動性が確保でき、圧送障害が起こり難いため、良好な施工性と混合状態を得やすいことがわかる。さらに、表8の結果からは、本発明品は非常に高い初期~長期にかけての強度発現性を具備できることがわかる。これに対し、従来技術の範疇や本発明から外れる技術の吹付用コンクリートでは、本発明品よりも強度が低いか、同等レベルの強度発現性であっても付着性に劣ることがわかる。 From the results in Table 7, it can be seen that the shotcrete of the present invention has high rapid setting properties to ensure sufficient adhesion during spraying construction. On the other hand, from the results in Table 8, it can be seen that the fluidity of concrete suitable for smooth pumping can be ensured both before and after adding the quick-setting agent, and pumping failure is unlikely to occur, making it easy to obtain good workability and mixing conditions. Furthermore, from the results in Table 8, it can be seen that the product of the present invention can exhibit extremely high initial to long-term strength development. On the other hand, it can be seen that shotcrete of the prior art or technology outside the present invention has lower strength than the product of the present invention, or has inferior adhesion even if it has the same level of strength development.

Claims (2)

次のベースコンクリート(A)とベースコンクリート中のポルトランドセメント含有量100質量部に対し7~14質量部の急結材(B)からなる吹付用高強度コンクリート。
A;ポルトランドセメント100質量部、ブレーン比表面積8000~10500cm2/gの無水石膏7~16質量部、減水剤0.3~2質量部、骨材及び水を含有するベースコンクリート。
B;化学成分としてのCaOとAl23の含有モル比(CaO/Al23)が1.8~2.7のカルシウムアルミネートを68~87質量%、無水石膏10~26質量%、アルカリ金属の硫酸塩及び/又は炭酸塩3~12質量%を含有する粉体状の急結材であって、急結材中の無水石膏がブレーン比表面積6600~8700cm2/gの石膏である急結材(但し、アルミン酸ナトリウムを含まない)。
A high-strength concrete for spraying consisting of the following base concrete (A) and a rapid setting agent (B) in an amount of 7 to 14 parts by mass per 100 parts by mass of Portland cement in the base concrete.
A: Base concrete containing 100 parts by mass of Portland cement, 7 to 16 parts by mass of anhydrite with a Blaine specific surface area of 8000 to 10,500 cm 2 /g, 0.3 to 2 parts by mass of a water reducing agent, aggregate and water.
B: Calcium aluminate with a molar ratio of CaO and Al 2 O 3 (CaO/Al 2 O 3 ) of 1.8 to 2.7 as chemical components, 68 to 87% by mass, anhydrite 10 to 26% by mass , a powdery quick-setting material containing 3 to 12% by mass of alkali metal sulfate and/or carbonate, wherein the anhydrite in the quick-setting material is gypsum with a Blaine specific surface area of 6600 to 8700 cm 2 /g. Certain quick-setting materials (but do not contain sodium aluminate).
急結材(B)がさらに硫酸アルミニウムを含有する請求項1記載の吹付用高強度コンクリート。 The high-strength concrete for spraying according to claim 1, wherein the rapid setting agent (B) further contains aluminum sulfate.
JP2019125873A 2018-07-06 2019-07-05 High strength concrete for spraying Active JP7351660B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2018128732 2018-07-06
JP2018128732 2018-07-06

Publications (2)

Publication Number Publication Date
JP2020011891A JP2020011891A (en) 2020-01-23
JP7351660B2 true JP7351660B2 (en) 2023-09-27

Family

ID=69169334

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2019125873A Active JP7351660B2 (en) 2018-07-06 2019-07-05 High strength concrete for spraying

Country Status (1)

Country Link
JP (1) JP7351660B2 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114804749A (en) * 2022-04-29 2022-07-29 中铁三局集团有限公司 Superfine modified silica micropowder low-resilience high-early-strength wet-spraying concrete and construction method thereof
CN116621539B (en) * 2023-06-10 2024-02-27 广州兴业混凝土搅拌有限公司 High-viscosity high-permeability-resistance fine stone sprayed concrete and preparation method thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000302503A (en) 1999-02-10 2000-10-31 Denki Kagaku Kogyo Kk Quick-setting agent, quick setting agent slurry, spraying material and spraying construction method using the same
JP2009114018A (en) 2007-11-06 2009-05-28 Taiheiyo Material Kk Admixture for quick hardening cement composition, quick hardening cement composition containing the same, quick hardening cement kneaded material and spraying material
JP2017105672A (en) 2015-12-10 2017-06-15 太平洋マテリアル株式会社 Concrete spray material

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3532068B2 (en) * 1997-05-21 2004-05-31 電気化学工業株式会社 Spraying material and spraying method using it
JPH11335152A (en) * 1998-05-28 1999-12-07 Taiheiyo Cement Corp Cement-based material and its spray application

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000302503A (en) 1999-02-10 2000-10-31 Denki Kagaku Kogyo Kk Quick-setting agent, quick setting agent slurry, spraying material and spraying construction method using the same
JP2009114018A (en) 2007-11-06 2009-05-28 Taiheiyo Material Kk Admixture for quick hardening cement composition, quick hardening cement composition containing the same, quick hardening cement kneaded material and spraying material
JP2017105672A (en) 2015-12-10 2017-06-15 太平洋マテリアル株式会社 Concrete spray material

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
眞田 千馬、津田 浩人,アルミン酸ソーダの劇物指定,耐火物,2019年09月01日,Vol.71 No.9,P.411-415

Also Published As

Publication number Publication date
JP2020011891A (en) 2020-01-23

Similar Documents

Publication Publication Date Title
JP2011037688A (en) Spray construction method for quick-setting spray cement concrete
JP5744499B2 (en) Grout cement composition and grout material
JP7351660B2 (en) High strength concrete for spraying
JP7077146B2 (en) Quickly miscible material
JP5785427B2 (en) Spraying material and spraying method using the same
JP6386902B2 (en) Shotcrete and manufacturing method thereof
JP4837172B2 (en) Spraying method
JP6732521B2 (en) Mortar for spraying
JP6662668B2 (en) Mortar for spraying
JP7286256B2 (en) shotcrete
JP7403918B2 (en) Rapid setting admixtures and shotcrete
JP2018104982A (en) Construction method of spray concrete
JP7437206B2 (en) Rapid setting admixtures and shotcrete
KR20020020132A (en) Cement Mineral Based Set Accelerator for Shotcrete
JP2003081664A (en) Quick setting agent, quick setting agent slurry, spraying material, and spraying method using the same
JP4145378B2 (en) Wet spraying method
JP2000044307A (en) Accelerator for high mobility shotcrete
JP2019006611A (en) Spray Concrete
JP4093622B2 (en) Quick setting sprayed concrete and spraying method using the same
JP2021091593A (en) Quick-setting admixture and sprayed concrete
JP2004210552A (en) Quick-setting agent for spray concrete
JP2023022666A (en) Spray method
JP2023022667A (en) Spray method and spray device
JP2000302505A (en) Accelerator, accelerator slurry, spraying material and method of spraying using the same
JPS5975976A (en) Static crushing agent

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20220609

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20221213

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20221220

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20230206

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20230516

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20230629

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20230912

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20230914

R150 Certificate of patent or registration of utility model

Ref document number: 7351660

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150