JP2001294464A - Rebound reducing agent, spraying material, and spraying method using the same - Google Patents

Abstract

(57) [Abstract] [Problem] A rebound reducing agent and spraying used when rapidly setting cement concrete is sprayed on a ground surface exposed by a tunnel, which can reduce a rebound rate and enables economical construction. To provide a material and a spraying method using the same. SOLUTION: The rebound reducing agent containing a polyalkylene oxide and a bisphenol-based condensate, the polyalkylene oxide has an average molecular weight of 1,000,000 to 5,000,000, and the bisphenol-based condensate has an average molecular weight of 5,000 to 30,000. A spraying material comprising the rebound reducing agent, the quick setting agent and the rebound reducing agent, or a cement; and a cement concrete containing cement and a part of the rebound reducing agent; The spraying method comprises mixing and spraying the agent and the rest of the rebound reducing agent immediately before spraying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rebound reducing agent, a spraying material, and a method for spraying quick-setting cement concrete onto an exposed ground surface in a tunnel such as a road, a railway, and a headrace. It relates to the spraying method using it. In the present invention, parts are based on mass unless otherwise specified. Further, the cement concrete in the present invention is a generic term for mortar and concrete.

[0002]

2. Description of the Related Art Conventionally, in order to prevent the collapse of an exposed ground such as a tunnel excavation, a method of spraying quick-setting concrete in which a quick-setting agent is mixed with concrete has been used. No. 60-004149). In this method, cement, aggregate, and water are usually metered and mixed at a mixing and mixing plant installed at the excavation site to prepare concrete for spraying, transported by an agitator truck, and pumped by a concrete pump. This is a method of mixing with a quick-setting agent pumped from the other by a joining pipe provided on the way to form quick-setting sprayable concrete, and spraying the concrete to a predetermined thickness on the ground surface. However, in this construction method, the rebound (bump) shown by (amount of quick-setting concrete dropped without being attached during spraying) / (total amount of quick-setting concrete used for spraying) x 100 (%) Return) rate is large, and there is a problem that it is not economically favorable.

The present inventor has studied to solve the above problems, and as a result, obtained a finding that the rebound rate at the time of spraying can be reduced by using a specific rebound reducing agent. Reached.

[0004]

That is, the present invention is a rebound reducing agent comprising a polyalkylene oxide and a bisphenol-based condensate, wherein the polyalkylene oxide has an average molecular weight of 1,000,000 to 5,000,000. It is a rebound reducing agent and the average molecular weight of the bisphenol condensate is
5,000 to 30,000 is the rebound reducing agent, a quick setting agent and the rebound reducing agent, or, furthermore, a spraying material containing cement, containing cement and a part of the rebound reducing agent This is a spraying method in which the cement concrete, the quick setting agent, and the rest of the rebound reducing agent are mixed and sprayed immediately before spraying.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The polyalkylene oxide (hereinafter referred to as PAO) used in the present invention gives viscosity to cement concrete by interaction with a bisphenol-based condensate,
This prevents cement concrete from dripping from the spraying surface immediately after spraying and reduces the rebound rate. PA
Examples of O include polyethylene oxide, polypropylene oxide, and polybutylene oxide. Of these, polyethylene oxide is preferable because of its large effect. PAO has an average molecular weight of 1,000,000 to 500
10,000 is preferred. If it is less than 1,000,000, the effect of reducing the rebound rate may be small, and if it exceeds 5,000,000, the pumpability of the quick-setting cement concrete may be reduced. PA
The amount of O used is preferably 0.001 to 0.5 part, more preferably 0.005 to 0.3 part, based on 100 parts of cement. If it is less than 0.001 part, the viscosity of the quick-setting cement concrete is small, dripping may occur when sprayed, and the rebound rate may increase, and if it exceeds 0.5 part, the viscosity of the quick-setting cement concrete increases and the pumpability is increased. May cause problems.

The bisphenol-based condensate used in the present invention is obtained by subjecting a bisphenol, an aromatic aminosulfonic acid and formaldehyde to a condensation reaction, and a commercially available product can be used. Specific examples of bisphenols include, for example, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, 2,2-
Bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxybiphenyl, and these Isomers and the like can be mentioned, and these can be used in combination.
Further, specific examples of the aromatic aminosulfonic acid include 4-aminobenzenesulfonic acid, 2-amino-5-methylbenzenesulfonic acid, and isomers thereof. The average molecular weight of the bisphenol-based condensate used in the present invention is preferably from 5,000 to 30,000. If the average molecular weight is less than 5,000, the effect of reducing the rebound rate may be small, and if it exceeds 30,000, the strength development may decrease. The amount of the bisphenol-based condensate to be used is preferably 0.1 to 1.0 part, more preferably 0.2 to 0.5 part, per 100 parts of cement. If it is less than 0.1 part, the effect of reducing the rebound rate may be small, and if it exceeds 1.0 part, the rebound rate may increase.

[0008] The cement used in the present invention is not particularly limited, and various types of Portland cement, such as ordinary, fast, super fast and low heat, and blast furnace slag, fly ash, fine limestone powder, Or various mixed cement mixed with silica, further, alumina cement, expanded cement, and colloid cement, etc.
Both can be used.

The quick-setting agent used in the present invention is not particularly limited, and examples of the inorganic salt include alkali metal aluminates, alkali metal carbonates, and silicates.
Examples of cement minerals include calcium aluminates and calcium sulfoaluminates, and examples of organic systems include triethanolamine and glycerin, which can be used in powder, slurry, or liquid form. It is. Among them, those containing calcium aluminates are preferable in terms of good setting properties and strength development. Although the amount of the quick setting agent cannot be uniquely defined by the material used, it is preferably about 3 to 5 parts with respect to 100 parts of the cement in the inorganic salt system, and preferably about 5 to 15 parts in the cement mineral system. . If the amount of the quick setting agent is less than this, sufficient initial setting may not be obtained, and rebound and peeling of cement concrete may increase,
If the amount of the quick-setting agent used is larger than this, the long-term strength development is reduced, which may be economically disadvantageous.

In the present invention, it is preferable to use a fibrous substance from the viewpoint of improving the impact resistance and elasticity of the cured product using the quick-setting cement concrete. As the fibrous substance, both inorganic and organic substances can be used. Examples of the inorganic fibrous substance include glass fiber, carbon fiber, rock wool, ceramic fiber, and metal fiber, and examples of the organic fibrous substance include vinylon fiber, polyethylene fiber, polypropylene fiber, polyacryl fiber, and cellulose. Fiber, polyvinyl alcohol fiber, polyamide fiber, pulp, hemp, and the like. Among these, metal fibers and vinylon fibers are preferable from the viewpoint of economy and effects. The length of the fibrous substance is preferably 50 mm or less, and more preferably 30 mm or less, from the viewpoint of pumpability and mixing properties. 50
If it exceeds mm, the pumping tube may be blocked. The amount of the fibrous substance used is preferably 0.5 to 10 parts by volume with respect to 100 parts by volume of cement concrete. If the amount is less than 0.5 parts by volume, the impact resistance and the elasticity may not be improved, and if the amount exceeds 10 parts by volume, the pumpability may decrease.

In the present invention, in addition to the above-mentioned materials and aggregates such as sand and gravel, a setting regulator, an AE agent, an antifoaming agent, a rust inhibitor,
Polymer emulsions such as SBR and polyacrylate,
Calcium compounds such as calcium oxide and calcium hydroxide, sulfates such as aluminum sulfate and alkali metal sulfate, clay minerals such as bentonite, zeolite, hydrotalcite, and ion exchangers such as hydrocalumite, inorganic phosphates, In addition, one or more kinds of boric acid and the like can be used in combination as long as the object of the present invention is not substantially inhibited.

As a method of mixing the quick setting agent, for example, a method in which cement concrete and a powdery quick setting agent are separately pneumatically fed and mixed together, or a method in which the cement concrete and the quick setting agent are mixed in a powder form before the quick setting agent is mixed and mixed. There is a method of merging and mixing a quick binder slurry made into a slurry by adding water to a binder and cement concrete, and any of them can be used.

In the present invention, as a device for mixing cement, aggregate, water and the like, an existing stirring device can be used. For example, a tilting mixer, an omni mixer, a V-type mixer,
Henschel mixers, Nauta mixers and the like can be used.

The spraying method of the present invention may be a dry spraying method or a wet spraying method. The dry spraying method is, for example, a method in which cement and aggregate are mixed and sent by air, and water and a quick-setting agent are mixed and mixed and sprayed. The wet spraying method is, for example, a method in which cement, aggregate, and water are mixed in advance to form cement concrete, which is air-fed and the quick-setting agent is mixed and mixed and sprayed. Of these, the dry spraying method may increase the amount of dust, so it is preferable to use the wet spraying method.

In the spraying method of the present invention, conventional spraying equipment and the like can be used. The spraying equipment is not particularly limited as long as spraying is sufficiently performed.
Ariba 28
"0" can be used for "Natom Cleat" manufactured by Chiyoda Manufacturing Co., Ltd. for pumping the quick-setting agent, and "Ankomat Pump" manufactured by Ptzmeister can be used for pumping the quick-setting agent slurry.

Further, the pressure of the compressed air for pumping the quick-setting admixture should be 0.01 to 0.3 MPa higher than the pressure of the cement concrete pumping so as to prevent the cement concrete from entering the pumping pipe of the quick-setting admixture and closing the pumping pipe. Is preferred. Further, the pumping speed of cement concrete is preferably 4 to 20 m ³ / h.

Further, at the confluence of the quick-setting agent and the cement concrete, it is possible to adopt a structure in which the shape of the pipe or the inner wall tends to be spiral or turbulent in order to improve the mixing property.

In the rebound reducing agent of the present invention, PAO is preferably mixed with cement concrete in advance, and the bisphenol-based condensate is preferably mixed with the cement concrete through a mixing pipe in front of the spray nozzle. When a bisphenol-based condensate is mixed with cement concrete, the viscosity increases and the pumpability deteriorates. Therefore, when added at a location other than the above, clogging and pulsation may occur. When mixing a bisphenol-based condensate with cement concrete, it is also possible to mix the bisphenol-based condensate with a quick-setting agent in advance and mix it with cement concrete.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

[0020] The unit amount of Experimental Example 1 each material, cement 450 kg / m ^3, a water 234kg / m ^3, fine aggregates 1,062kg / m ^3, and coarse aggregate 576kg / m ^3, furthermore, concrete 100 parts by volume Concrete, to which 1 part by volume of a fibrous substance was added, and a concrete pumping machine “Ariba 28” was prepared under the conditions of a pumping speed of 15 m ³ / h and a pumping pressure of 0.4 MPa.
0 ". Further, the amount of PAO shown in Table 1 was previously mixed with the concrete in 100 parts of the cement in the concrete, and 0.2 part of the bisphenol-based condensate A was previously mixed with the quick setting agent and used. For 100 parts of quick setting agent, add 70 parts of water together with compressed air under pressurized condition,
It was a quick setting slurry. Into the mixing pipe provided in front of the spray nozzle, 100 parts of cement in the concrete was blown in so that the quick setting agent became 10 parts, and the quick setting concrete was blown into the simulated tunnel, and the rebound rate was increased. The sagging, pumpability, and compressive strength were evaluated. The results are also shown in Table 1.

<Materials Used> Cement: Ordinary Portland cement, commercial product, Blaine specific surface area 3,200 cm ² / g, specific gravity 3.16 Fine aggregate: Himekawa river sand, Niigata prefecture, specific gravity 2.62 Coarse aggregate: Himekawa river gravel, Niigata prefecture Specific gravity 2.64, maximum aggregate size 10 mm Quick setting agent: mixture consisting of calcium aluminate / gypsum / aluminate = 100/100/14 (weight ratio). However, calcium aluminate corresponds to 12CaO · 7Al ₂ O ₃ composition, by using the amorphous ones with Blaine specific surface area of 6,100cm ² / g, gypsum type II anhydrous Blaine specific surface area gypsum 6,000 ² / g
The aluminate used was sodium aluminate. PAO A: Polyethylene oxide, average molecular weight 200
10,000, commercially available PAO: polyethylene oxide, average molecular weight 100
10,000, commercially available PAOha: polyethylene oxide, average molecular weight 500
10,000, commercial product Bisphenol-based condensate A: average molecular weight 20,000, commercial product Fibrous substance: steel fiber, length 30 mm, commercial product

<Measurement Method> Rebound rate: Rapid-setting concrete was sprayed at a pumping speed of 15 m ³ / h for 5 minutes onto a simulated tunnel having a height of 4.5 m and a width of 5.5 m. After spraying, measure the amount of quick-setting concrete and fibrous material that has fallen without adhering. (Rebound rate) = (quick-setting concrete or fibrous material that has fallen without adhering during spraying) It was calculated from the formula: / (whole quick-setting concrete or fibrous substance used for spraying) × 100 (% by weight). Sagging: The state after spraying of the quick-setting concrete was observed, and ◎ was given when no sagging occurred, ○ was given when a little occurred, and × was given when many occurred. Pumpability: The pressure inside the pumping pipe when spraying quick-setting concrete was measured. When the pressure in the pipe is 0.4 to 0.55 MPa, even if the pressure becomes 0.6 MPa or more at which the inside of the pipe is easily blocked, the pressure is reduced by applying an impact to the pumping pipe to reduce the pressure to 0.
The case where the pressure was 4 to 0.55 MPa was rated as ○, and the case where the pressure feed pipe was closed and did not reach 0.4 to 0.55 MPa even when an impact was applied was rated as ×. Compressive strength: Compressive strength of 3 hours old is 25cm wide x 25 long
The pin installed on the pull-out formwork of cm is covered with quick-setting concrete from the surface of the pull-out formwork, the pin is pulled out from the back side of the formwork, and the pull-out strength at that time is obtained, (compression strength) = (pull-out strength) × The compressive strength was calculated from the formula of 4 / (shear area). Compressive strength after 1 day of age is 50cm width x 50 length
The quick-setting concrete was sprayed onto a mold having a size of 20 cm and a thickness of 20 cm, and the strength of a specimen having a diameter of 5 cm and a length of 10 cm collected and cored was measured with a pressure tester.

[0023]

[Table 1]

Experimental Example 2 Experimental example 1 was conducted except that 0.01 part of PAO and 100 parts of the bisphenol-based condensate shown in Table 2 were used for 100 parts of cement.
The same was done. The results are also shown in Table 2. The bisphenol-based condensate was previously mixed with the quick-setting agent before use.

<Materials used> Bisphenol-based condensate B: average molecular weight 5,000, commercial product Bisphenol-based condensate C: average molecular weight 10,000, commercial product Bisphenol-based condensate D: average molecular weight 30,000, commercial product

[0026]

[Table 2]

Experimental Example 3 An experiment was performed in the same manner as in Experimental Example 1 except that 0.01 parts of PAO, 0.2 parts of bisphenol-based condensate A, and the quick setting agent shown in Table 3 were used for 100 parts of cement. The results are also shown in Table 3.

[0028]

[Table 3]

[0029]

According to the present invention, the rebound reducing agent, the spraying material, and the spraying method using the same can reduce the rebound rate of quick-setting cement concrete at the time of spraying, thereby enabling economical construction. .

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 61/34 C08L 61/34 71/02 71/02 E21D 11/10 E21D 11/10 D // C04B 103 : 12 C04B 103: 12 111: 00 111: 00 F term (reference) 2D055 DB03 KA00 KA08 LA10 4G012 MB00 MB23 MB26 PB05 PB11 PB25 PB36 PC06 PC11 4J002 CC28W CH02X DE186 DE226 DG016 DJ006 DM007 EC056 EN106 FD010 FD206 GL00

Claims (7)

[Claims] 1. A rebound reducing agent comprising a polyalkylene oxide and a bisphenol-based condensate. 2. The rebound reducing agent according to claim 1, wherein the polyalkylene oxide has an average molecular weight of 1,000,000 to 5,000,000. 3. The bisphenol-based condensate has an average molecular weight of 3.
3. The method according to claim 1, wherein the number is from 5,000 to 30,000.
The rebound reducing agent according to the above. 4. A spraying material comprising a quick-setting agent and the rebound reducing agent according to claim 1. 5. A spray material comprising a cement, a quick setting agent and a rebound reducing agent according to claim 1. Description: 6. A cement concrete containing a cement and a part of the rebound reducing agent according to claim 1; a quick-setting agent; and the cement concrete according to claim 1. A spraying method comprising mixing and spraying the remainder of the rebound reducing agent immediately before spraying. 7. A spraying method characterized by mixing and spraying cement concrete containing cement and polyalkylene oxide, a quick setting agent, and a bisphenol-based condensate immediately before spraying.