JP7403918B2 - Rapid setting admixtures and shotcrete - Google Patents
Rapid setting admixtures and shotcrete Download PDFInfo
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- JP7403918B2 JP7403918B2 JP2019216606A JP2019216606A JP7403918B2 JP 7403918 B2 JP7403918 B2 JP 7403918B2 JP 2019216606 A JP2019216606 A JP 2019216606A JP 2019216606 A JP2019216606 A JP 2019216606A JP 7403918 B2 JP7403918 B2 JP 7403918B2
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- 239000011378 shotcrete Substances 0.000 title claims description 38
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 33
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 claims description 31
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 20
- 239000004568 cement Substances 0.000 claims description 20
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 18
- -1 alkaline earth metal sulfate Chemical class 0.000 claims description 18
- 229910052936 alkali metal sulfate Inorganic materials 0.000 claims description 17
- 239000003638 chemical reducing agent Substances 0.000 claims description 16
- 150000008064 anhydrides Chemical class 0.000 claims description 15
- 239000000126 substance Substances 0.000 claims description 9
- 229910000288 alkali metal carbonate Inorganic materials 0.000 claims description 8
- 150000008041 alkali metal carbonates Chemical class 0.000 claims description 8
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 claims description 8
- 239000002562 thickening agent Substances 0.000 claims description 8
- 239000012615 aggregate Substances 0.000 claims description 5
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 3
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 3
- 239000011575 calcium Substances 0.000 claims description 3
- 239000004567 concrete Substances 0.000 description 31
- 239000002585 base Substances 0.000 description 19
- 238000005507 spraying Methods 0.000 description 18
- 238000011161 development Methods 0.000 description 16
- 239000000203 mixture Substances 0.000 description 16
- 230000007774 longterm Effects 0.000 description 13
- 239000000463 material Substances 0.000 description 10
- 239000004570 mortar (masonry) Substances 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 7
- 238000010276 construction Methods 0.000 description 7
- 239000000843 powder Substances 0.000 description 7
- 239000011398 Portland cement Substances 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- 238000004017 vitrification Methods 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000035515 penetration Effects 0.000 description 5
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 4
- 238000002347 injection Methods 0.000 description 4
- 239000007924 injection Substances 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 229910052708 sodium Inorganic materials 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 235000019738 Limestone Nutrition 0.000 description 3
- 239000004480 active ingredient Substances 0.000 description 3
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000006028 limestone Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 230000009257 reactivity Effects 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000004575 stone Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 150000004687 hexahydrates Chemical class 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 238000007586 pull-out test Methods 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229910001388 sodium aluminate Inorganic materials 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- WPJGWJITSIEFRP-UHFFFAOYSA-N 1,3,5-triazine-2,4,6-triamine;hydrate Chemical compound O.NC1=NC(N)=NC(N)=N1 WPJGWJITSIEFRP-UHFFFAOYSA-N 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 238000005280 amorphization Methods 0.000 description 1
- 229910052925 anhydrite Inorganic materials 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- 239000011400 blast furnace cement Substances 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000009415 formwork Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000011440 grout Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000003317 industrial substance Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000010813 internal standard method Methods 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000002075 main ingredient Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- PSZYNBSKGUBXEH-UHFFFAOYSA-N naphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(S(=O)(=O)O)=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-N 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Landscapes
- Lining And Supports For Tunnels (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
本発明は、急結混和材及び吹付コンクリートに関する。 The present invention relates to quick setting admixtures and shotcrete.
トンネル、採掘抗、地下空間等において、掘削面の崩壊防止、採掘時又は掘削後の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。吹付コンクリートは急結性によって施工対象物への付着性を担保している。急結性付与のために急結成分をコンクリートに混和し、例えば、カルシウムアルミネートやアルミン酸ナトリウム等を有効成分とする粉体急結剤は、強力な急結性を付与でき、液体急結剤と比べると強度的にも高いコンクリートが得られやすい。吹付コンクリートの一般的な施工法である湿式吹付工法では、例えば、少なくともセメント、水及び骨材を秤量・混合してベースコンクリートを作製し、アジテーター車等を介した上で、施工時に吹付装置にポンプ圧送する。吹付装置内では別送の粉体又は液体の急結剤を圧送中のベースコンクリートに添加し、吹付装置の吹付ノズル内で混合を進めて吹付コンクリートを形成し、これをノズル端孔から吹付ける。また、もう一つの施工法である乾式吹付工法では、水及び液体以外の少なくともセメントと骨材と粉体急結剤を秤量・混合してドライミックスコンクリートを作製し、これをその貯留槽等から施工時に吹付装置まで空気圧送する。吹付装置内では圧送中のドライミックスコンクリートに水を添加し、吹付ノズルに圧送されるまでに混合を進めて吹付コンクリートを形成し、同様に吹き付ける。何れの工法でも、吹付装置内の急結成分が水と接する地点（接水地点）から吹付ノズル端の吐出孔までを移動する間に、混合がなされて吹付コンクリートが形成される。混合に使われる距離は通常は数十ｃｍ～数ｍの距離であり、その移動時間が混合時間になる。一般に、この距離が長いほど混合が進み、混合性が高まり、組織的にも性状的にもより均一なコンクリートを得易くなる。 Shotcrete is used in tunnels, mining pits, underground spaces, etc. to prevent collapse of excavated surfaces and to strengthen the ground during or after excavation. Shotcrete's rapid setting ensures adhesion to the object being constructed. Rapid-setting ingredients are mixed into concrete to give it quick-setting properties. For example, powder quick-setting agents containing calcium aluminate, sodium aluminate, etc. as active ingredients can impart strong quick-setting properties, and liquid quick-setting agents can be used as active ingredients. It is easier to obtain concrete with higher strength compared to concrete. In the wet spraying method, which is a common construction method for shotcrete, for example, at least cement, water, and aggregate are weighed and mixed to prepare a base concrete, which is then passed through an agitator vehicle, etc., and then transferred to a spraying device during construction. Pump. In the spraying device, a separately delivered powder or liquid quick-setting agent is added to the base concrete being pumped, and mixing is progressed in the spraying nozzle of the spraying device to form shotcrete, which is sprayed from the nozzle end hole. In addition, in the dry spraying method, which is another construction method, dry mix concrete is prepared by weighing and mixing at least cement, aggregate, and powder quick-setting agent other than water and liquid, and this is poured from the storage tank etc. During construction, air is sent to the spraying equipment. In the spraying device, water is added to the dry mix concrete being pumped, and the mixture is mixed to form shotcrete before being pumped to the spray nozzle, which is then sprayed in the same way. In either construction method, while the rapid components in the spraying device move from the point where they come into contact with water (water contact point) to the discharge hole at the end of the spray nozzle, they are mixed and shotcrete is formed. The distance used for mixing is usually several tens of centimeters to several meters, and the time taken to move the mixture is the mixing time. Generally, the longer this distance is, the more the mixing progresses, the better the mixability, and the easier it is to obtain concrete that is more uniform both in structure and properties.
このような吹付コンクリートを得るために、混和される粉体状の急結材は、一般には、前述した急結成分に、諸性状を調整する助剤が加えられたものである。例えば、化学成分としてのＣａＯ含有量を多くしたカルシウムアルミネートに、硬化促進のセッコウを配合し、これらに初期強度発現性を高めるアルミン酸ナトリウムや凝結促進の炭酸ナトリウム等加えた高アルカリ化の従来の代表的な粉体急結材（例えば、特許文献１～３参照。）では、高い急結性と初期強度発現性の付与作用の具備を一義的な目的としている。このため、急結材が水と接した後、極短時間で凝結が起こる。 In order to obtain such shotcrete, the powdery quick-setting material that is mixed is generally the above-mentioned quick-setting component plus an auxiliary agent for adjusting various properties. For example, conventional highly alkaline products include calcium aluminate with a high CaO content as a chemical component, mixed with gypsum to accelerate hardening, and sodium aluminate to increase early strength development and sodium carbonate to accelerate setting. The primary purpose of typical powder quick-setting materials (for example, see Patent Documents 1 to 3) is to provide high quick-setting properties and the ability to develop initial strength. Therefore, after the rapid setting material comes into contact with water, setting occurs in a very short time.
ところで、水が存在する等の施工環境では従来の吹付コンクリートは付着性が足りず、更なる急結性が求められていた。しかしながら、吹付コンクリートの急結性を向上させると凝結が早くなり、ノズルの詰りや混合性が低下し、また長期強度も得られにくいといった問題があった。 However, in construction environments where water is present, conventional shotcrete does not have sufficient adhesion, and even more rapid setting has been required. However, improving the quick setting properties of shotcrete causes problems such as faster setting, clogging of nozzles, poor mixing properties, and difficulty in achieving long-term strength.
したがって、本発明は、早期の急結性を有しながら施工性も確保し、且つ、長期の強度発現性に優れる急結混和材及び吹付コンクリートを提供することを目的とする。 Therefore, an object of the present invention is to provide a quick-set admixture and shotcrete that has quick-setting properties at an early stage while also ensuring workability and has excellent long-term strength development.
本発明者らは、上記課題について鋭意検討を重ねた結果、カルシウムアルミネートの化学成分の割合、カルシウムアルミネートの含有量、アルカリ金属の硫酸塩及びアルカリ土類金属の硫酸塩の比率を調整することで、早期の急結性を有しながら施工性も確保し、且つ、長期の強度発現性に優れる急結混和材及び吹付コンクリートが得られることを見出した。 As a result of intensive studies on the above-mentioned issues, the present inventors adjusted the ratio of chemical components of calcium aluminate, the content of calcium aluminate, and the ratio of alkali metal sulfate and alkaline earth metal sulfate. It has been found that, by doing so, it is possible to obtain a quick-set admixture and shotcrete that has early quick-setting properties, ensures workability, and has excellent long-term strength development.
すなわち、本発明は以下の［１］～［５］で示される。
［１］化学成分としてのＣａＯとＡｌ２Ｏ３の含有モル比（ＣａＯ／Ａｌ２Ｏ３）が２．１～２．７のカルシウムアルミネート、アルカリ金属の硫酸塩及びアルカリ土類金属の硫酸塩を含む急結混和材であり、カルシウムアルミネートの含有量が、急結混和材全質量を基準として７０～８７質量％であり、アルカリ金属の硫酸塩及びアルカリ土類金属の硫酸塩の質量比（［アルカリ土類金属の硫酸塩の質量］／［アルカリ金属の硫酸塩の質量］）が、無水物換算で１．１～２．５である、急結混和材。
［２］硫酸アルミニウムを更に含む、［１］の急結混和材。
［３］アルカリ金属の炭酸塩を更に含む、［１］又は［２］の急結混和材。
［４］セメント、骨材、水及び［１］～［３］のいずれかの急結混和材を含み、急結混和材の含有量が、セメント１００質量部に対して６～１４質量部である、吹付コンクリート。
［５］減水剤及び／又は増粘剤を更に含む、［４］の吹付コンクリート。
That is, the present invention is shown in [1] to [5] below.
[1] Calcium aluminate, alkali metal sulfate, and alkaline earth metal sulfuric acid with a molar ratio of CaO and Al 2 O 3 (CaO/Al 2 O 3 ) of 2.1 to 2.7 as chemical components. It is a quick setting admixture containing salt, the content of calcium aluminate is 70 to 87% by mass based on the total mass of the quick setting admixture, and the mass of alkali metal sulfate and alkaline earth metal sulfate is A rapid setting admixture having a ratio ([mass of alkaline earth metal sulfate]/[mass of alkali metal sulfate]) from 1.1 to 2.5 in terms of anhydride.
[2] The quick-setting admixture of [1], further containing aluminum sulfate.
[3] The quick-setting admixture of [1] or [2], further comprising an alkali metal carbonate.
[4] Contains cement, aggregate, water, and any of the quick-setting admixtures of [1] to [3], and the content of the quick-setting admixture is 6 to 14 parts by mass per 100 parts by mass of cement. Yes, shotcrete.
[5] The shotcrete of [4], further comprising a water reducer and/or a thickener.
本発明によれば、早期の急結性を有しながら施工性も確保し、且つ、長期の強度発現性に優れる急結混和材及び吹付コンクリートを提供することができる。 According to the present invention, it is possible to provide a quick-set admixture and shotcrete that have early quick-set properties, ensure workability, and have excellent long-term strength development.
以下、本発明の一実施形態について詳細に説明する。 Hereinafter, one embodiment of the present invention will be described in detail.
本実施形態の急結混和材は、化学成分としてのＣａＯとＡｌ２Ｏ３の含有モル比（ＣａＯ／Ａｌ２Ｏ３）が２．１～２．７のカルシウムアルミネート、アルカリ金属の硫酸塩及びアルカリ土類金属の硫酸塩を含む。 The quick-setting admixture of this embodiment is composed of calcium aluminate and alkali metal sulfate having a molar ratio of CaO and Al 2 O 3 (CaO/Al 2 O 3 ) of 2.1 to 2.7 as chemical components. and alkaline earth metal sulfates.
カルシウムアルミネートは、ＣａＯとＡｌ２Ｏ３を主要化学成分とする無機水和活性物質であり、ＣａＯとＡｌ２Ｏ３の含有モル比（ＣａＯ／Ａｌ２Ｏ３）が２．１～２．７である。ＣａＯとＡｌ２Ｏ３の含有モル比が上記範囲外であると、急結性と施工性の両立が困難となる。ＣａＯとＡｌ２Ｏ３の含有モル比は、より優れた急結性が得られやすいという観点から、２．２～２．６５であることが好ましく、２．３～２．６であることがより好ましい。カルシウムアルミネートには、原料由来のＣａＯとＡｌ２Ｏ３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んでもよい。 Calcium aluminate is an inorganic hydration active material whose main chemical components are CaO and Al 2 O 3 , and the molar ratio of CaO to Al 2 O 3 (CaO/Al 2 O 3 ) is 2.1 to 2. It is 7. If the molar ratio of CaO and Al 2 O 3 is outside the above range, it will be difficult to achieve both rapid setting and workability. The molar ratio of CaO and Al 2 O 3 is preferably 2.2 to 2.65, more preferably 2.3 to 2.6, from the viewpoint of easily obtaining better rapid setting properties. More preferred. Calcium aluminate may also contain foreign components such as impurities other than CaO and Al 2 O 3 derived from the raw materials, regardless of their existing form, to the extent that the effects of the present invention are not impaired.
カルシウムアルミネートは結晶質、非晶質、又はその混合物のいずれも用いることができる。カルシウムアルミネートは、より優れた急結性が得られやすいという観点から、非晶質化の度合いであるガラス化率が６０質量％以上であることが好ましく、８０質量％以上であることがより好ましく、９５質量％以上であることが更に好ましい。カルシウムアルミネートの粉末度は特に制限されないが、コンクリートへの急結混和材に使用したときに適度な反応活性が得られやすいことから、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であることが好ましく、例えば、ブレーン比表面積３０００～６５００ｃｍ２／ｇの粉末度が挙げられる。 Calcium aluminate may be crystalline, amorphous, or a mixture thereof. Calcium aluminate preferably has a vitrification rate of 60% by mass or more, and more preferably 80% by mass or more, from the viewpoint of easily obtaining better rapid setting properties. It is preferably 95% by mass or more, and more preferably 95% by mass or more. There are no particular restrictions on the powder level of calcium aluminate, but since it is easy to obtain a suitable level of reaction activity when used as a quick-setting admixture for concrete, it should be at least as fine as the cement in the hydraulic composition to which it is mixed. It is preferable to have a fineness higher than that, and for example, a fineness having a Blaine specific surface area of 3000 to 6500 cm 2 /g is exemplified.
カルシウムアルミネートの含有率は、急結混和材全質量を基準として、７０～８７質量％である。カルシウムアルミネートの含有率が上記範囲外であると、急結性と施工性の両立が困難になり、長期の強度発現性も優れない。カルシウムアルミネートの含有率は、早期の急結性、施工性、長期の強度発現性に優れやすいという観点から、急結混和材全質量を基準として７３～８５質量％であることが好ましく、７５～８３質量％であることがより好ましい。 The content of calcium aluminate is 70 to 87% by mass based on the total mass of the quick-setting admixture. If the content of calcium aluminate is outside the above range, it will be difficult to achieve both rapid setting and workability, and long-term strength development will also be poor. The content of calcium aluminate is preferably 73 to 85% by mass based on the total mass of the quick-setting admixture, from the viewpoint of being excellent in early rapid setting, workability, and long-term strength development. More preferably, it is 83% by mass.
カルシウムアルミネートは、例えば、ＣａＯ源となる原料及びＡｌ２Ｏ３源となる原料を、目的とする化学成分としてのＣａＯとＡｌ２Ｏ３の含有モル比が得られるように配合した原料混合物を、溶融するまで加熱することで得られる。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、冷却速度等の冷却条件に応じて、非晶質化の度合であるガラス化率を調整できる。 Calcium aluminate is produced by, for example, a raw material mixture in which a raw material serving as a CaO source and a raw material serving as an Al 2 O 3 source are blended so as to obtain the desired molar ratio of CaO and Al 2 O 3 as chemical components. , obtained by heating until melted. 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, so depending on cooling conditions such as cooling rate, the degree of amorphization of glass You can adjust the conversion rate.
アルカリ金属の硫酸塩は、特に限定されるものではなくいずれのものも使用することができ、反応性に優れることから無水物であることが好ましい。アルカリ金属としては、リチウム、ナトリウム、カリウム等が挙げられ、中でもナトリウムが好ましい。アルカリ金属の硫酸塩は、一種を単独で用いてもよく、二種以上を併せて用いてもよい。アルカリ金属の硫酸塩の含有量は、カルシウムアルミネート１００質量部に対して、無水物換算で４～１６質量部であることが好ましく、５～１５質量部であることがより好ましく、６～１４質量部であることが更に好ましい。アルカリ金属の硫酸塩の含有量が上記範囲内であれば、早期の急結性及び長期の強度発現性に優れやすい。 The alkali metal sulfate is not particularly limited and any one can be used, and anhydrides are preferred because they have excellent reactivity. Examples of the alkali metal include lithium, sodium, potassium, etc. Among them, sodium is preferred. One type of alkali metal sulfate may be used alone, or two or more types may be used in combination. The content of the alkali metal sulfate is preferably 4 to 16 parts by mass, more preferably 5 to 15 parts by mass, and more preferably 6 to 14 parts by mass in terms of anhydride, per 100 parts by mass of calcium aluminate. More preferably, it is parts by mass. If the content of the alkali metal sulfate is within the above range, early rapid setting and long-term strength development are likely to be excellent.
アルカリ土類金属の硫酸塩は、特に限定されるものではなくいずれのものも使用することができ、反応性に優れることから無水物であることが好ましい。アルカリ土類金属としては、マグネシウム、カルシウム等が挙げられ、中でもカルシウムが好ましい。アルカリ土類金属の硫酸塩は、一種を単独で用いてもよく、二種以上を併せて用いてもよい。アルカリ土類金属の硫酸塩の粒径や粒度も特に制限されるものではなく、例えば、ブレーン比表面積が４０００～６５００ｃｍ２／ｇ程度のものが挙げられる。アルカリ土類金属の硫酸塩の含有量は、カルシウムアルミネート１００質量部に対して、無水物換算で１０～３５質量部であることが好ましく、１１～３０質量部であることがより好ましく、１２～２５質量部であることが更に好ましい。アルカリ土類金属の硫酸塩の含有量が上記範囲内であれば、長期の強度発現性に優れやすい。 The alkaline earth metal sulfate is not particularly limited, and any sulfate can be used, and anhydrides are preferred because they have excellent reactivity. Examples of the alkaline earth metal include magnesium, calcium, and the like, with calcium being preferred. One type of alkaline earth metal sulfate may be used alone, or two or more types may be used in combination. There are no particular limitations on the particle size or grain size of the alkaline earth metal sulfate, and examples thereof include those having a Blaine specific surface area of about 4000 to 6500 cm 2 /g. The content of alkaline earth metal sulfate is preferably 10 to 35 parts by mass, more preferably 11 to 30 parts by mass, and more preferably 11 to 30 parts by mass in terms of anhydride, per 100 parts by mass of calcium aluminate. More preferably, the amount is 25 parts by mass. If the content of alkaline earth metal sulfate is within the above range, long-term strength development is likely to be excellent.
本実施形態に係る急結混和材において、アルカリ金属の硫酸塩及びアルカリ土類金属の硫酸塩の質量比（［アルカリ土類金属の硫酸塩の質量］／［アルカリ金属の硫酸塩の質量］）は、無水物換算で１．１～２．５である。アルカリ金属の硫酸塩及びアルカリ土類金属の硫酸塩の質量比が上記範囲外であると、早期の急結性が低下し、施工性も優れず、長期の強度発現性も得られにくい。アルカリ金属の硫酸塩及びアルカリ土類金属の硫酸塩の質量比は、早期の急結性、施工性、長期の強度発現性が得られやすいという観点から、無水物換算で１．２～２．４であることが好ましく、１．３～２．３５であることがより好ましい。 In the rapid setting admixture according to the present embodiment, the mass ratio of alkali metal sulfate and alkaline earth metal sulfate ([mass of alkaline earth metal sulfate]/[mass of alkali metal sulfate]) is 1.1 to 2.5 in terms of anhydride. If the mass ratio of the alkali metal sulfate and the alkaline earth metal sulfate is outside the above range, early rapid setting will be reduced, workability will not be excellent, and long-term strength development will be difficult to obtain. The mass ratio of the alkali metal sulfate and the alkaline earth metal sulfate is 1.2 to 2.0 on anhydride basis from the viewpoint of facilitating early rapid setting, workability, and long-term strength development. It is preferably 4, and more preferably 1.3 to 2.35.
本実施形態の急結混和材は硫酸アルミニウムを含んでもよい。硫酸アルミニウムはいずれの形態でもよく、例えば、１６水和物、無水物等が挙げられ、中でも１６水和物が好ましい。硫酸アルミニウムの含有量は、カルシウムアルミネート１００質量部に対して、無水物換算で０～１０質量部であることが好ましく、０．５～９質量部であることがより好ましく、１～８質量部であることが更に好ましい。硫酸アルミニウムの含有量が上記範囲内であれば、低温環境下で急結性を高めた場合であっても長期の強度発現性を確保しやすい。 The rapid setting admixture of this embodiment may contain aluminum sulfate. Aluminum sulfate may be in any form, for example, hexahydrate, anhydride, etc., with hexahydrate being preferred. The content of aluminum sulfate is preferably 0 to 10 parts by weight, more preferably 0.5 to 9 parts by weight, and 1 to 8 parts by weight in terms of anhydride based on 100 parts by weight of calcium aluminate. It is more preferable that it is part. If the content of aluminum sulfate is within the above range, long-term strength development can be easily ensured even if rapid setting is enhanced in a low-temperature environment.
本実施形態の急結混和材はアルカリ金属の炭酸塩を含んでもよい。アルカリ金属の炭酸塩は特に限定されるものではなくいずれのものも使用することができ、反応性に優れることから無水物であることが好ましい。アルカリ金属としては、リチウム、ナトリウム、カリウム等が挙げられ、中でもナトリウムが好ましい。アルカリ金属の炭酸塩は、一種を単独で用いてもよく、二種以上を併せて用いてもよい。アルカリ金属の炭酸塩の粒度は特に限定されず、例えば、ブレーン比表面積で概ね３０００～６５００ｃｍ２／ｇで最大粒径１ｍｍ以下の粉体の粉体を用いることができる。アルカリ金属の炭酸塩の含有量は、カルシウムアルミネート１００質量部に対して、無水物換算で１～１０質量部であることが好ましく、１．５～９質量部であることがより好ましく、２～８質量部であることが更に好ましい。アルカリ金属の炭酸塩の含有量が上記範囲内であれば、初期の強度発現性が更に向上する。 The rapid setting admixture of this embodiment may contain an alkali metal carbonate. The alkali metal carbonate is not particularly limited and any carbonate can be used, and anhydrides are preferred because they have excellent reactivity. Examples of the alkali metal include lithium, sodium, potassium, etc. Among them, sodium is preferred. One type of alkali metal carbonate may be used alone, or two or more types may be used in combination. The particle size of the alkali metal carbonate is not particularly limited, and for example, powder having a Blaine specific surface area of approximately 3000 to 6500 cm 2 /g and a maximum particle size of 1 mm or less can be used. The content of the alkali metal carbonate is preferably 1 to 10 parts by mass, more preferably 1.5 to 9 parts by mass, in terms of anhydride, per 100 parts by mass of calcium aluminate. More preferably, the amount is 8 parts by mass. If the content of the alkali metal carbonate is within the above range, the initial strength development is further improved.
本実施形態に係る急結混和材は、上記の各成分を混合して製造される。混合方法は特に制限されるものではなく、例えば、傾動ミキサ、パン型ミキサ、２軸ミキサ、グラウトミキサ、ホバートミキサ、オムニミキサ等の汎用的なミキサを用いることができる。 The rapid setting admixture according to this embodiment is manufactured by mixing the above-mentioned components. The mixing method is not particularly limited, and for example, general-purpose mixers such as a tilting mixer, a pan-type mixer, a two-shaft mixer, a grout mixer, a Hobart mixer, and an omni mixer can be used.
本実施形態の急結混和材は、セメント、骨材及び水と混合することで吹付コンクリートとして調製することができる。急結混和材の含有量は、セメント１００質量部に対して６～１４質量部であることが好ましく、６．５～１２質量部であることがより好ましく、７～１０質量部であることが更に好ましい。急結混和材の含有量が上記範囲内であれば、早期の急結性及び施工性を両立しやすい。 The rapid setting admixture of this embodiment can be prepared as shotcrete by mixing with cement, aggregate, and water. The content of the rapid setting admixture is preferably 6 to 14 parts by mass, more preferably 6.5 to 12 parts by mass, and preferably 7 to 10 parts by mass based on 100 parts by mass of cement. More preferred. If the content of the quick-setting admixture is within the above range, it is easy to achieve both early quick-setting properties and workability.
セメントは、ポルトランドセメントが好ましく、ポルトランドセメントは何れの種類のものでもよく、例えば、普通、早強、超早強、中庸熱、低熱、耐硫酸塩の各種ポルトランドセメントが挙げられる。セメントとしては、ポルトランドセメントを含む例えば高炉セメントやフライアッシュセメント等の混合セメントも使用できる。セメントは、一種を単独で用いてもよく、二種以上を併せて用いてもよい。ポルトランドセメントを使用する場合の粒度は特に限定されず、例えば、ＪＩＳ規格（ＪＩＳ Ｒ ５２１０：２０１９）の２５００ｃｍ２／ｇ以上のものが挙げられる。 The cement is preferably Portland cement, and any type of Portland cement may be used, such as ordinary, early-strength, ultra-early-strength, medium-heat, low-heat, and sulfate-resistant Portland cements. As the cement, mixed cements including Portland cement, such as blast furnace cement and fly ash cement, can also be used. One type of cement may be used alone, or two or more types may be used in combination. When using Portland cement, the particle size is not particularly limited, and examples thereof include those of 2500 cm 2 /g or more according to the JIS standard (JIS R 5210:2019).
骨材は、細骨材及び粗骨材が挙げられる。細骨材は、モルタルやコンクリートに使用できる細骨材なら特に限定されない。粗骨材はコンクリートに使用できる粗骨材なら特に限定されない。細骨材及び粗骨材とも、所定の骨材強度が確保し易く、他の含有成分との比重差が少ないため材料分離が生じ難いことから、表乾密度が２．３～２．９ｇ／ｃｍ３の骨材を使用することが好ましい。このような骨材の具体例としては、細骨材は、珪砂や石灰石砂等の天然骨材、安山岩、砂岩、玄武岩等の砕砂等が挙げられ、粗骨材は、珪石、石灰石、安山岩、砂岩、玄武岩等の砕石や砂利が挙げられる。骨材は、一種を単独で用いてもよく、二種以上を併せて用いてもよい。 Examples of the aggregate include fine aggregate and coarse aggregate. The fine aggregate is not particularly limited as long as it can be used for mortar or concrete. The coarse aggregate is not particularly limited as long as it can be used for concrete. Both fine and coarse aggregates have a surface dry density of 2.3 to 2.9 g/min because it is easy to ensure the specified aggregate strength and there is little difference in specific gravity from other contained components, so material separation is difficult to occur. It is preferable to use aggregate of cm 3 . Specific examples of such aggregates include fine aggregates such as natural aggregates such as silica sand and limestone sand, crushed sand such as andesite, sandstone, and basalt, and coarse aggregates such as silica stone, limestone, andesite, and the like. Examples include crushed stone and gravel such as sandstone and basalt. One type of aggregate may be used alone, or two or more types may be used in combination.
吹付コンクリート中の骨材の含有量は特に限定されるものではないが、施工時におけるコンクリート圧送性に優れやすいという観点から、セメント含有量１００質量部に対し、細骨材及び粗骨材の合計が３００～５７０質量部であることが好ましく、３８０～５５０質量部であることがより好ましく、４２０～５２０質量部であることが更に好ましい。細骨材及び粗骨材を併用する場合、細骨材率（全骨材中の細骨材の質量割合）は５４～６９質量％であることが好ましく、５５～６５質量％であることがより好ましく、５６～６３質量％であることが更に好ましい。 The content of aggregate in shotcrete is not particularly limited, but from the viewpoint of easy concrete pumpability during construction, the total amount of fine aggregate and coarse aggregate for 100 parts by mass of cement content. is preferably 300 to 570 parts by weight, more preferably 380 to 550 parts by weight, and even more preferably 420 to 520 parts by weight. When using fine aggregate and coarse aggregate together, the fine aggregate ratio (mass proportion of fine aggregate in all aggregates) is preferably 54 to 69 mass%, and preferably 55 to 65 mass%. The content is more preferably 56 to 63% by mass.
本実施形態の吹付コンクリートは減水剤を含んでもよい。減水剤は、分散剤、高性能減水剤、高性能ＡＥ減水剤、ＡＥ減水剤、流動化剤を含む。このような減水剤としては、ＪＩＳ Ａ ６２０４：２０１１「コンクリート用化学混和剤」に規定される減水剤が挙げられる。減水剤としては、例えば、ポリカルボン酸系減水剤、ナフタレンスルホン酸系減水剤、リグニンスルホン酸系減水剤、メラミン系減水剤、アクリル系減水剤が挙げられる。これらの中では、ポリカルボン酸系減水剤が好ましい。減水剤は、一種を単独で用いてもよく、二種以上を併せて用いてもよい。減水剤の含有量は、水量を抑制しながらも流動性を確保しやすいという観点から、例えば、セメント１００質量部に対して、固形分換算で０．１５～０．８質量部であってもよく、０．２５～０．６質量部であってもよい。 The shotcrete of this embodiment may also contain a water reducing agent. Water reducers include dispersants, superplasticizers, superplasticizers, AE water reducers, and superplasticizers. Examples of such water reducing agents include water reducing agents specified in JIS A 6204:2011 "Chemical admixtures for concrete". Examples of the water reducing agent include polycarboxylic acid water reducing agents, naphthalene sulfonic acid water reducing agents, lignin sulfonic acid water reducing agents, melamine water reducing agents, and acrylic water reducing agents. Among these, polycarboxylic acid water reducing agents are preferred. One type of water reducing agent may be used alone, or two or more types may be used in combination. The content of the water reducing agent may be, for example, 0.15 to 0.8 parts by mass in terms of solid content per 100 parts by mass of cement, from the viewpoint of easily ensuring fluidity while suppressing the amount of water. The amount may be 0.25 to 0.6 parts by mass.
本実施形態の吹付コンクリートは増粘剤を含んでもよい。増粘剤はモルタルやコンクリートに使用できる増粘剤であれば特に限定されず、溶性のセルロース誘導体を有効成分とするものが好ましい。増粘剤は、一種を単独で用いてもよく、二種以上を併せて用いてもよい。増粘剤の含有量は、吹付時の粉塵の発生を抑制しやすいという観点から、セメント含有量１００質量部に対し、固形分換算で０．０３～０．１５質量部であることが好ましく、０．０６～０．１０質量部であることがより好ましい。 The shotcrete of this embodiment may also contain a thickener. The thickener is not particularly limited as long as it can be used for mortar or concrete, and those containing a soluble cellulose derivative as an active ingredient are preferred. One type of thickener may be used alone, or two or more types may be used in combination. The content of the thickener is preferably 0.03 to 0.15 parts by mass in terms of solid content, based on 100 parts by mass of cement, from the viewpoint of easily suppressing the generation of dust during spraying. More preferably, it is 0.06 to 0.10 parts by mass.
本実施形態の吹付コンクリートは、上記以外の成分も、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。含有可能な成分として、短繊維、ポゾラン反応性物質等が挙げられる。 The shotcrete of this embodiment can also contain components other than those mentioned above, within a range that does not impede the effects of the present invention. Components that can be included include short fibers, pozzolan reactive substances, and the like.
本実施形態の吹付コンクリートは、使用する目的、場所等の要因に応じて水の量を適宜調整することができる。水の含有量は、セメント１００質量部に対して５２～６８質量部であることが好ましく、５３～６７質量部であることがより好ましく、５５～６５質量部であることが更に好ましい。水の含有量が上記範囲内であれば、強度発現性に優れる傾向となる。 The amount of water in the shotcrete of this embodiment can be adjusted as appropriate depending on factors such as the purpose of use and the location. The content of water is preferably 52 to 68 parts by mass, more preferably 53 to 67 parts by mass, and even more preferably 55 to 65 parts by mass, based on 100 parts by mass of cement. If the water content is within the above range, strength development tends to be excellent.
吹付コンクリートは、例えば、急結混和材を除く各材料を水と混練してベースコンクリートとし、吹付ノズルの先端でベースコンクリート及び急結混和材を混合して吹付ける湿式吹付工法により製造してもよく、急結混和材を含む各材料を混合してベース組成物とし、吹付ノズルの先端でベース組成物及び水を混合して吹付ける乾式吹付工法により製造してもよい。吹付コンクリートは、粉塵やリバウンドがより低減されやすいという観点から、湿式吹付け工法により製造することが好ましい。 Shotcrete can also be produced by, for example, a wet spraying method in which each material except the quick-set admixture is mixed with water to form a base concrete, and the base concrete and quick-set admixture are mixed and sprayed at the tip of a spray nozzle. It may be manufactured by a dry spraying method in which a base composition is prepared by mixing various materials including a quick-setting admixture, and the base composition and water are mixed and sprayed at the tip of a spray nozzle. Shotcrete is preferably manufactured by a wet shotcrete method from the viewpoint that dust and rebound are more easily reduced.
本実施形態の急結混和材及び吹付コンクリートは、早期の急結性を有しながら施工性も確保し、且つ、長期の強度発現性に優れたものである。そのため、通常のトンネル壁面や斜面への吹付けだけでなく、水が多い場所等の付着性が悪く早期の急結性が求められる環境下においても好適に使用することができる。 The quick setting admixture and shotcrete of this embodiment have early quick setting properties, ensure workability, and have excellent long-term strength development. Therefore, it can be suitably used not only for ordinary spraying on tunnel walls and slopes, but also in environments where adhesion is poor and rapid rapid setting is required, such as in places with a lot of water.
以下、実施例を挙げて本発明を詳細に説明するが、本発明はこれ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 explained in detail with reference to Examples, but the present invention is not limited thereto. 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Ａｌ２Ｏ３を用い、ＣａＯ及びＡｌ２Ｏ３の含有モル比（ＣａＯ／Ａｌ２Ｏ３、Ｃ／Ａ比）の値が以下に表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、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、冷却物を得た。冷却物のガラス化率については、窒素ガスの流速を最大値よりも落として吹付けることで調整した。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。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。
ガラス化率（質量％）＝｛１－（Ｍ２／Ｍ１）｝×１００
[Preparation of calcium aluminate]
Using commercially available industrial chemicals CaCO 3 and Al 2 O 3 , calcium aluminate with a molar ratio of CaO and Al 2 O 3 (CaO/Al 2 O 3, C/A ratio) as shown below was obtained. The ingredients were weighed and blended to make a raw material mixture 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 object at a maximum flow rate of about 30 mL/sec to rapidly cool it, thereby obtaining a cooled object. The vitrification rate of the cooled material was adjusted by spraying nitrogen gas at a flow rate lower than the maximum value. Each cooled material was pulverized in an all-steel ball mill, and then sized to have a Blaine specific surface area of about 5400 cm 2 /g using a classifier. The vitrification rate of calcium aluminate is determined 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.; M2 was calculated, and the remainder was considered to be a pure glass phase, and the vitrification rate was calculated using the following formula.
Vitrification rate (mass%) = {1-(M2/M1)}×100
［材料］
カルシウムアルミネート：ＣａＯ／Ａｌ２Ｏ３が２．０～３．０、ガラス化率９９％以上、ブレーン比表面積５４００ｃｍ２／ｇ
硫酸ナトリウム試薬（無水芒硝）
硫酸カルシウム試薬（無水石膏）
硫酸アルミニウム試薬（１６水和物）
炭酸ナトリウム試薬
セメント：普通ポルトランドセメント、ブレーン比表面積３２００ｃｍ２／ｇ、密度３．１５ｇ／ｃｍ３
細骨材：石灰石細骨材（表乾密度；２．６５ｇ／ｃｍ３、中心粒径；０．６ｍｍ）
粗骨材：砕石（表乾密度；２．７４ｇ／ｃｍ３、粒径５～１５ｍｍ）
増粘剤：プロピルメチルセルロースを主成分とするもの
[material]
Calcium aluminate: CaO/Al 2 O 3 2.0 to 3.0, vitrification rate 99% or more, Blaine specific surface area 5400 cm 2 /g
Sodium sulfate reagent (anhydrous sodium sulfate)
Calcium sulfate reagent (anhydrite)
Aluminum sulfate reagent (16 hydrate)
Sodium carbonate reagent cement: Ordinary Portland cement, Blaine specific surface area 3200cm 2 /g, density 3.15g/cm 3
Fine aggregate: limestone fine aggregate (surface dry density: 2.65 g/cm 3 , center particle size: 0.6 mm)
Coarse aggregate: Crushed stone (surface dry density: 2.74 g/cm 3 , particle size 5-15 mm)
Thickener: The main ingredient is propyl methylcellulose.
［急結混和材の作製］
各材料を表１に示す割合として配合し、ヘンシェルミキサで１分間混合した。
[Preparation of rapid setting admixture]
Each material was blended in the proportions shown in Table 1 and mixed for 1 minute using a Henschel mixer.
［ベースコンクリートの作製］
セメント１００質量部に対して細骨材２９７質量部、粗骨材２０４質量部、増粘剤０．０８質量部（固形分換算）を混合し、次いで水６０質量部を加えてコンクリートミキサで２分間混合し、ベースコンクリートを作製した。
[Preparation of base concrete]
To 100 parts by mass of cement, 297 parts by mass of fine aggregate, 204 parts by mass of coarse aggregate, and 0.08 parts by mass of thickener (in terms of solid content) were mixed, then 60 parts by mass of water was added, and the mixture was mixed with a concrete mixer for 2 hours. The mixture was mixed for a minute to form a base concrete.
［吹付コンクリートの作製］
ベースコンクリートを混練後直ちに供給用タンクに入れ、そこから長さ約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。吹付装置は、ベースコンクリートが圧送される内径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添加物（急結混和材）を供給添加するための円筒状側管と、吹付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する市販品である。ここで、添加物供給用の側管は、圧送管本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。ト字状管の直線上に位置する二方の管口に圧送管本管と噴射用ノズルがそれぞれ接続され、残りの管口に、別送される急結性混和材の供給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混和材の添加位置（ベースコンクリートと急結混和材の合流地点）から噴射用ノズル孔端までの距離の間に、ベースコンクリートと急結混和材の混合がなされ、その距離（以下、混合距離と称す。）は３．２ｍとした。急結混和材は圧搾空気により所定量を空気圧送し、これを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され、吹付コンクリートを作製した。
急結混和材の添加量は表１に示すとおりである。
[Preparation of shotcrete]
Immediately after the base concrete was mixed, it was put into a supply tank, and from there 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 device consists of a pressure feed pipe with an inner diameter of 2 inches through which the base concrete is pumped, and a cylindrical side connected to the side of the pipe at an angle of inclination of approximately 30 degrees for supplying additives (rapid setting admixtures) to the base concrete. This is a commercially available product that basically consists of a pipe and a 2-inch inner diameter (tip hole diameter) injection nozzle for spraying shotcrete. Here, the side pipe for supplying additives was formed by interposing a steel T-shaped pipe (three-way pipe) between the main pipe for pressure feeding and the injection nozzle. The pressure feeding pipe main pipe and the injection nozzle are respectively connected to the two pipe ports located on a straight line of the T-shaped pipe, and the supply pipe for the quick-setting admixture, which is sent separately, is connected to the remaining pipe port. Structure. Between the point where the quick-setting admixture is added to the base concrete in the T-shaped pipe (the meeting point of the base concrete and the quick-setting admixture) and the end of the injection nozzle hole, the base concrete and the quick-setting admixture are added. Mixing was performed at a distance (hereinafter referred to as mixing distance) of 3.2 m. A predetermined amount of quick-setting admixture is pneumatically delivered using compressed air, and this is added to the base concrete being pumped in a spraying device.The added concrete is mixed while traveling a predetermined mixing distance to create shotcrete. did.
The amount of the quick setting admixture added is as shown in Table 1.
［急結性の評価］
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、モルタル配合に変更したベースモルタルをベースコンクリートと同様の手順で作製した。得られたベースモルタルに急結混和材を表１に示す割合で添加し、高速ミキサで５秒間混合し、モルタル混練物を作製した。
急結混和材添加から、２０秒経過後、４５秒経過後、６０秒経過後及び１８０秒経過後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を表２に示す。また、表中「＞１６（Ｎ／ｍｍ２）」の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。
[Evaluation of rapid setting]
In the formulation of base concrete, the content of fine aggregate is equal to the total content of coarse aggregate and fine aggregate, and coarse aggregate is not included, and other components and their contents are A base mortar with a changed mortar composition was produced in the same manner as the base concrete without any change. Rapid setting admixtures were added to the obtained base mortar in the proportions shown in Table 1, and mixed for 5 seconds with a high-speed mixer to produce a mortar kneaded product.
The proctor penetration resistance value of the mortar mixture was measured 20 seconds, 45 seconds, 60 seconds, and 180 seconds after the addition of the quick-setting admixture to evaluate the quick-setting property. 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 shown in Table 2. Further, in the table, ">16 (N/mm 2 )" indicates that although the proctor needle could be implanted, the measurement limit (maximum 16 N/mm 2 ) of the equipment used this time was exceeded.
［吹付コンクリートの強度発現性の評価］
混合距離を３．２ｍにし、作製した吹付コンクリートを、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２８日にした供試体を得た。この材齢２８日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、同様に作製した吹付コンクリートを、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４時間及び１日の吹付コンクリートの圧縮強度を測定した。各供試体の強度測定の結果を表２に示す。
[Evaluation of strength development of shotcrete]
Immediately after the mixing distance was set to 3.2 m, the produced shotcrete was sprayed into a molding form having internal dimensions of 30 x 40 x 20 cm, so as 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 with a core drill, and the specimen was aged 28 days. I got it. The unconfined compressive strength of this 28-day old specimen was measured using an Amsler type compressive strength tester. In addition, shotcrete prepared in the same manner was subjected to a pullout test in accordance with JSCE-G561 using a pullout test form and embedding tool specified in the Japan Society of Civil Engineers standard JSCE-G561. Through this test, the compressive strength of shotcrete with an age of 4 hours and one day was measured. Table 2 shows the results of strength measurements for each specimen.
表２の結果から、実施例の吹付コンクリートは２０秒時点でのプロクター貫入抵抗値が１～３．５Ｎ／ｍｍ２の範囲に収まっていることが示された。これは早期の急結性を有しながら、施工性を十分に担保できている結果であった。また、実施例の吹付コンクリートは、材齢２８日の圧縮強度が２５Ｎ／ｍｍ２以上であり、長期における強度発現性にも優れることが示された。 From the results in Table 2, it was shown that the proctor penetration resistance value of the shotcrete of the example at 20 seconds fell within the range of 1 to 3.5 N/mm 2 . This was a result of being able to sufficiently ensure workability while exhibiting early and rapid setting properties. Further, the shotcrete of the example had a compressive strength of 25 N/mm 2 or more at 28 days of age, indicating that it has excellent long-term strength development.
Claims (4)
前記アルカリ土類金属はカルシウムであり、
前記カルシウムアルミネートの含有量が、前記急結混和材全質量を基準として７０～８７質量％であり、
前記アルカリ金属の硫酸塩及び前記アルカリ土類金属の硫酸塩の質量比（［アルカリ土類金属の硫酸塩の質量］／［アルカリ金属の硫酸塩の質量］）が、無水物換算で１．１～２．５であり、
前記アルカリ金属の硫酸塩の含有量は前記カルシウムアルミネート１００質量部に対し、無水物換算で４～１６質量部であり、
前記アルカリ土類金属の硫酸塩の含有量は前記カルシウムアルミネート１００質量部に対し、無水物換算で１０～３５質量部であり、
前記硫酸アルミニウムの含有量は前記カルシウムアルミネート１００質量部に対し、無水物換算で０～９質量部である、急結混和材。 Contains calcium aluminate, alkali metal sulfate, and alkaline earth metal sulfate with a molar ratio of CaO and Al 2 O 3 (CaO / Al 2 O 3 ) as chemical components of 2.1 to 2.7. , a rapid setting admixture that may include aluminum sulfate;
the alkaline earth metal is calcium;
The content of the calcium aluminate is 70 to 87% by mass based on the total mass of the rapid setting admixture,
The mass ratio of the alkali metal sulfate and the alkaline earth metal sulfate ([mass of alkaline earth metal sulfate]/[mass of alkali metal sulfate]) is 1.1 in terms of anhydride. ~2.5,
The content of the alkali metal sulfate is 4 to 16 parts by mass in terms of anhydride based on 100 parts by mass of the calcium aluminate,
The content of the alkaline earth metal sulfate is 10 to 35 parts by mass in terms of anhydride based on 100 parts by mass of the calcium aluminate,
The content of the aluminum sulfate is 0 to 9 parts by mass in terms of anhydride based on 100 parts by mass of the calcium aluminate.
前記急結混和材の含有量が、前記セメント１００質量部に対して６～１４質量部である、吹付コンクリート。 Containing cement, aggregate, water and the rapid setting admixture according to claim 1 or 2,
Shotcrete, wherein the content of the rapid setting admixture is 6 to 14 parts by mass based on 100 parts by mass of the cement.
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| WO2015182170A1 (en) | 2014-05-30 | 2015-12-03 | 太平洋マテリアル株式会社 | Admixture for rapid setting |
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