JPH09227198A - Cement composition, spraying material and spraying technique using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spraying cement composition which can be used mainly in road works or its repairing works by spraying to the inner surfaces of tunnels, slopes or for stabilizing natural ground and slopes, enables the workers to work under good environmental conditions even in small working spaces, stabilizes the natural ground and bed rocks with a thickness of 2-3cm with high strength development after spraying and high working efficiency. SOLUTION: This cement composition contains cement, aggregates with a maximum particle size of 2.5mm, a hydrated lime-containing substance and an alkali metal aluminate. In addition, it may contains phosphate or organic acid and, when needed, fibers. In the spraying operation, the A liquid containing cement and the like and the B liquid containing an alkali metal aluminate are forcedly fed to the sprayer separately and hardened.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cement composition,
The present invention relates to a spraying material which is sprayed mainly on a tunnel inner surface or a slope after excavating a tunnel or after constructing a slope such as a road, and used for road construction or repair work for stabilizing the ground or slope.

[0002]

2. Description of the Related Art In recent years, small-sized headrace tunnels with a diameter of 2 to 3 m are often excavated by a tunnel boring machine (TBM), and sprayed concrete is used to stabilize rock mass after excavation. Is used. However, in the conventional spraying, a large construction machine is used and concrete to be used has to be carried in from the outside of the mine, so that there is a problem that the working space and the lifetime of the concrete are easily restricted. Further, since a large amount of air is blown, a large amount of dust is generated, which causes problems such as deterioration of the working environment and deterioration of the air cooling device of the TBM.

As a means for solving these problems, there has been proposed a spraying method using a mortar or a rapid-hardening material slurry which has been kneaded in batch, which shortens the working time and improves the working environment (Japanese Patent Laid-Open No. 3-122040). Gazette). However, since mortar and rapid hardening material slurry are batch kneading, the work is complicated and the life time of each material is limited, so that the material must be discarded when it takes time due to mechanical troubles. was there. In addition, the hardening time of the rapid hardening mortar which mixed the mortar and the rapid hardening material slurry is 20
Since it is about 30 seconds, it is necessary to repeat spraying to make spray mortar to a certain thickness, especially at spring locations where it does not adhere sufficiently and is easily washed away. Requires skill of workers.

As a result of various studies to solve the above problems, the present inventor has completed the present invention by finding that the above problems can be solved by using a specific spray material.

[0005]

Means for Solving the Problems That is, the present invention provides a cement composition containing cement, an aggregate having a maximum particle size of 2.5 mm, a substance containing slaked lime, and an alkali metal aluminate. A cement composition containing an aggregate having a particle diameter of 2.5 mm, a substance containing slaked lime, an alkali metal aluminate, and a phosphate or an organic acid, and further, if necessary, a cement, a maximum particle diameter of 2.5. mm aggregate,
And a slaked lime-containing substance, or a spray material comprising a solution A containing a phosphate or an organic acid, and optionally a fiber, and a solution B containing an alkali metal aluminate, The spraying method is characterized in that the liquid A and the liquid B are separately fed under pressure to be cured.

The present invention will be described in more detail below.

As the cement used in the present invention, various kinds of ordinary, early strength, super early strength, etc. portland cements, and various mixed cements obtained by mixing these portland cements with blast furnace slag, fly ash, or silica are used. , And 3CaO ・ SiO ₂ and 11CaO ・ 7Al ₂ O ₃・ CaF ₂
It is possible to use modified Portland cement containing as a main component.

The aggregate used in the present invention includes natural sand, silica sand,
Both lime and sand can be used, and the maximum particle size is
It is 2.5 mm or less, preferably 1.5 mm or less. If the maximum particle size exceeds 2.5 mm, there will be a large amount of rebound during spraying, and pumpability may deteriorate. The amount of aggregate used is preferably 50 to 300 parts by weight with respect to 100 parts by weight of cement, in terms of workability, initial strength development, and durability.
More preferably 100 to 200 parts by weight. If it is less than 50 parts by weight, the durability will be low, and if it exceeds 300 parts by weight, the initial strength development will be low and rebound may increase.

The slaked lime-containing substance used in the present invention can be slaked lime or a slag of carbide produced as a by-product when calcium carbide is mixed with water to generate acetylene gas. Is preferred. The particle size of the slaked lime-containing substance is not particularly limited,
From the viewpoint of solubility, it is preferably 100 μm or less, more preferably 60 μm or less. The amount of slaked lime-containing substance used is 10
With respect to 0 parts by weight, 1 to 10 parts by weight is preferable, and 3 to 7 parts by weight is more preferable. If the amount is less than 1 part by weight, the desired coagulation force may not be obtained, and in particular, it may become noticeable when applied at low temperature. If the amount exceeds 10 parts by weight, the coagulation force may increase but the long-term durability may deteriorate. is there.

The phosphates used in the present invention include phosphates of phosphoric acid monophosphate, phosphoric acid diphosphate, and phosphoric acid triphosphate, pyrophosphate, tripolyphosphate, trimetaphosphate, hexametaphosphate, and tetraphosphate. Examples thereof include sodium salts and potassium salts of polyphosphate, and of these, monosodium phosphate and sodium tripolyphosphate are preferably used from the viewpoint of cohesive strength and strength development. The particle size of the phosphate salt is not particularly limited, and any particle size of commercially available products can be used, but 0.25 mm or less is preferable from the viewpoint of solubility. The amount of phosphate used is preferably 0.2 to 3.0 parts by weight, more preferably 0.7 to 2.0 parts by weight, based on 100 parts by weight of cement. If the amount is less than 0.2 parts by weight, the desired coagulation force cannot be obtained, and this may be remarkable especially in low-temperature and high-temperature operations.If it exceeds 3.0 parts by weight, gelation time becomes longer and It may cause sagging or peeling at the time of attachment, and the strength development property may decrease.

Examples of the organic acid used in the present invention include citric acid, gluconic acid, tartaric acid, malic acid and sodium salt thereof, and one or more of them can be used. Among these, use of citric acid, gluconic acid, and tartaric acid is preferable. The particle size of the organic acid is not particularly limited, but the commercially available products having the particle size can be used. The amount of organic acid used is preferably 0.1 to 2.0 parts by weight, more preferably 0.3 to 1.0 part by weight, based on 100 parts by weight of cement. If the amount is less than 0.1 parts by weight, the desired coagulation force cannot be obtained, and this may be remarkable especially in low-temperature and high-temperature construction, and if it exceeds 2.0 parts by weight, gelation time becomes longer and blown. It may cause sagging or peeling during attachment.

The fibers used in the present invention include inorganic fibers such as ceramic whisker fibers and alkali glass fibers, organic fibers such as carbon fibers, polyethylene fibers, vinylon fibers, aramid fibers, and polyacrylic fibers, and Steel fibers and the like are mentioned, and among them, alkali-resistant glass fibers, carbon fibers, polyethylene fibers, vinylon fibers, and polyacrylic fibers are preferably used. Although the length of the fiber is not particularly limited, it is preferably 3 to 30 mm, more preferably 6 to 12 mm. The amount of the fibers used is preferably 0.4 to 1.5 parts by weight, more preferably 0.5 to 1.2 parts by weight, based on 100 parts by weight of the mixed mortar. If it is less than 0.4 parts by weight, the desired shear strength cannot be obtained, and if it exceeds 1.5 parts by weight, the mixing dispersibility during dry mixing may be deteriorated or the strength development may be deteriorated.

Alkali metal aluminate used in the present invention
As salt (hereinafter referred to as alkali aluminate), aluminum
Sodium phosphate and potassium aluminate can be mentioned and dissolved
It is preferable to use potassium aluminate from the viewpoint of the property. Departure
In the clear, alkali aluminate is liquid or once aluminum
The alkaline acid solution is dried to obtain, for example, a solid content of 50% by weight.
It is possible to use it as a slurry, but as a liquid
For storage, it is preferable to use an aqueous potassium aluminate solution.
New If the alkali aluminate is an aqueous solution, its Na_TwoO
/ Al_TwoO_ThreeMolar ratio or K_TwoO / Al _TwoO_ThreeMolar ratio of 1.5 to 2.0
Are preferred. Na_TwoO / Al_TwoO_ThreeMolar ratio or K_TwoO / Al_TwoO _Three
If the molar ratio is less than 1.5, it will dissolve even at 100 ° C.
It can be difficult. Dry the alkali aluminate slurry
It is also possible to dry it and suspend it in water before use.
is there. Aqueous alkali aluminate solution
Aluminum (OH) and aluminum hydroxide (Al (OH)_Three ) Or hydroxy
Potassium iodide (KOH) and Al (OH)_ThreeTo Na_TwoO / Al_TwoO_ThreeMolar ratio
Is K_TwoO / Al_TwoO_ThreeFormulated to have a molar ratio of 1.5 to 2.0
Melt at 100 ° C, adjust to a concentration of 50% by weight, and adjust.
Can be manufactured. In the present invention, alluminate
50 parts of sodium carbonate or potassium carbonate in an aqueous solution of potassium
50% by weight aqueous solution of alkali aluminate
Also use a mixture of 20 to 100 parts by weight with respect to 100 parts by weight.
It is possible to use Amount of alkali aluminate used
Is preferably 3 to 10 parts by weight with respect to 100 parts by weight of cement.
Therefore, 5 to 8 parts by weight is more preferable. Below 3 parts by weight
The desired coagulation force was not obtained, and it was noticeable especially at low temperatures.
It may be remarkable, and even if it exceeds 10 parts by weight, a large cohesive force
May not be obtained and conversely the long-term durability may deteriorate.

The pump for pumping the aqueous solution of alkali aluminate is not particularly limited, but a piston type pump, a squeeze type pump, a snake type pump or the like can be used.

The method of using each material used in the present invention is not particularly limited, but for example, cement, aggregate having a maximum particle size of 2.5 mm, and slaked lime-containing substance, and phosphorus to be blended as necessary. Acid salts or organic acids are dry-mixed in a dry state, and then the dry-mixed mortar and water are kneaded to form solution A, an aqueous solution of alkali aluminate is solution B, and solutions A and B are separately pumped. It is possible to spray it.

It is preferable to use dry-mixed mortar from the viewpoint that it can be used simply by mixing and kneading water without mixing and mixing the respective materials at the spraying site. As a mixing mixer used in dry mixing, any mixer such as a V-type blender or a Nauta mixer can be used, and the Nauta mixer is preferably used from the viewpoint of fiber dispersibility. As the mixer used for kneading the mortar, a batch kneading mixer such as a tarai type mixer, a hover type mixer, a twin screw mixer, and an omni mixer can be used.

Here, the amount of water used for kneading is not particularly limited, but in order to obtain fluidity that can be pumped by a pump, for example, a flow value of 180 to 260 mm.
It is preferable to add water so that

The pump for feeding the kneaded mortar is not particularly limited, and for example, a piston type pump, a squeeze type pump, a snake type pump and the like can be used. Further, for example, the supplied spray material is kneaded with water press-fitted by the blade of the tip of the mixer, and is continuously kneaded by a snake-type pump connected thereto, and is kneaded and pressure-fed by a continuous kneading pressure-feeding device. There is a method, etc., and this method is preferable in terms of workability.

The method of mixing the mortar that has been kneaded and pressure-fed with the aqueous solution of alkali aluminate is not particularly limited, but for example, as used in the New Australian Construction Method (NATM), etc. , When mixing the alkaline aluminate aqueous solution into the mortar using a Y-shaped tube, the alkaline aluminate aqueous solution is conveyed by air,
It is possible to spray. Further, it is also possible to press-fit an aqueous solution of alkali aluminate pumped into an inlet piece having several holes around the ring with air, mix it with mortar and spray it. A mixing method using an inlay piece is preferable from the viewpoint of mixing property.

[0020]

The present invention will be described in more detail based on the following examples.

Example 1 100 parts by weight of cement, 100 parts by weight of aggregate and slaked lime-containing substance A shown in Table 1 were mixed and dry-mixed
20 parts by weight of water was added to 100 parts by weight, and the mixture was kneaded with a mortar mixer according to JIS R 5201 to prepare mortar. To 100 parts by weight of cement in this mortar, add 5 parts by weight of alkali aluminate α, knead for 10 seconds, quickly fill the mold, and measure the proctor penetration resistance value at 20 ° C to start and finish Time and also compression strength measurements were taken. The results are also shown in Table 1.

<Materials used> Cement: ordinary Portland cement, manufactured by Denki Kagaku Kogyo Co., Ltd. Aggregate: No. 6 silica sand and No. 7 silica sand equivalent mixture, maximum particle size
20mm slaked lime-containing substance A: slaked lime from Chichibu Alkali aluminate α: K ₂ O / Al ₂ O ₃ molar ratio of 1.5

<Measurement Method> Initial time: Time (minutes) when the proctor penetration resistance value reaches 500 psi Termination time: Time (minute) when the proctor penetration resistance value reaches 4,000 psi Compressive strength: 20 ° C according to JIS R 5201 , Measured at specified age (N / mm ² )

[0024]

[Table 1]

Example 2 100 parts by weight of cement to 100 parts by weight of aggregate, and Table 2
The same procedure as in Example 1 was carried out except that the slaked lime-containing substance A and the phosphate a shown in 1 were mixed and dry-mixed. The results are also shown in Table 2.

<Materials used> Phosphate a: monobasic sodium phosphate, first-class reagent

[0027]

[Table 2]

Example 3 Example 3 was repeated except that the amounts of slaked lime-containing substance B and phosphate b shown in Table 3 were used. The results are also shown in Table 3.

<Material used> Slaked lime-containing substance B: Carbite slag Phosphate b: Sodium tripolyphosphate, first-class reagent

[0030]

[Table 3]

Example 4 Example 4 was repeated except that the amount of the aqueous alkali aluminate solution shown in Table 4 was used. The results are also shown in Table 4.

[0032]

[Table 4]

Example 5 100 parts by weight of cement, 100 parts by weight of aggregate, 5 parts by weight of slaked lime-containing substance A, 1 part by weight of phosphate a, and fiber 1.
Six parts by weight were mixed with a Nauta mixer to prepare 200 kg of premixed dry mortar. The produced dry mortar was put into a G4 continuous mixer pump manufactured by PFT of Germany, water was added so as to obtain a flow value of 200 mm to form a mortar, and the mixture was continuously kneaded and pressure-fed at a capacity of 2.5 m ³ / hr. In addition, 2.5 kgf of alkali aluminate α was pumped with a plunger pump so that the alkali aluminate α was 6 parts by weight with respect to 100 parts by weight of cement in the mortar. A mortar passing through the inlet piece was pressed into the mortar together with an air of / cm ² and mixed, and sprayed in an area of 1 m ² so that the thickness was about 2 to 3 cm. Similarly, spraying was performed on a triple mold of 4 × 4 × 16 cm, and the compressive strength for each predetermined age was measured. As for the spraying condition, there were few dusts, no sagging, little rebound, and high cohesive force immediately after spraying, and the results that satisfied the desired properties were obtained. The compressive strength was 1.52N / mm ^{2 for} 1 hour, 2.61N / mm ² for 28 hours, 28
The result was almost the same as 50.7 N / mm ² per day.

<Material used> Fiber: Vinylon fiber length 6 mm, made by Kuraray Co., Ltd.

Example 6 The pumping speed and rebound rate were measured in the same manner as in Example 5 except that the aggregate shown in Table 5 was used. The results are also shown in Table 5.

<Measurement method> Pumping speed: pumping capacity when operated for 1 minute Rebound rate: 1 minute when sprayed on the side wall (bounced amount / sprayed amount) × 100

[0037]

[Table 5]

Example 7 The rebound rate, the compressive strength, and the presence or absence of cracks were measured in the same manner as in Example 6 except that the amount of aggregate shown in Table 6 was used. The results are also shown in Table 6.

<Measurement method> Presence or absence of cracks: Spraying on an area of 1 m ² and a thickness of 2 cm, and observing after 1 month

[0040]

[Table 6]

Example 8 Example 8 was carried out in the same manner as in Example 2 except that an organic acid b was used as shown in Table 7 in place of the phosphate. The results are also shown in Table 7.

<Materials used> Organic acids a: citric acid, first-class reagent

[0043]

[Table 7]

Example 9 The procedure of Example 8 was repeated except that the slaked lime-containing substance B and the organic acids B were used. The results are also shown in Table 8.

<Materials used> Organic acids b: sodium gluconate, first-class reagent

[0046]

[Table 8]

Example 10 The procedure of Example 8 was repeated except that the amount of the aqueous alkali aluminate solution shown in Table 9 was used. The results are also shown in Table 9.

[0048]

[Table 9]

Example 11 Except that organic acid B was used instead of phosphate.
The same procedure as in Example 5 was performed. As a result, the situation of spraying is powder
Less dust, no sagging, little bounce, no blowing
The cohesive strength immediately after application is high, and the desired properties are satisfied.
The fruit was obtained. Also, the compressive strength is almost the same as the indoor test
2.31N / mm in 1 hour^Two 30.2 N / mm per day ^Two , In 28 days 5
3.4 N / mm^TwoAlmost similar results were obtained.

[0050]

EFFECTS OF THE INVENTION By using the cement composition of the present invention, it is possible to work in a good environment even in a narrow work space such as a tunnel having a small cross section, and since the strength development after spraying is high, a thinness of 2-3 cm is obtained. By doing so, it is possible to stabilize the rock mass and rock mass after excavation. Furthermore, by using a continuous mixer pump, work efficiency is enhanced.

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Claims (7)

[Claims] 1. A cement composition comprising cement, an aggregate having a maximum particle size of 2.5 mm, a substance containing slaked lime, and an alkali metal aluminate. 2. A cement composition containing cement, an aggregate having a maximum particle size of 2.5 mm, a substance containing slaked lime, an alkali metal aluminate, and a phosphate or an organic acid. 3. The cement composition according to claim 1, which further comprises fibers. 4. A spray material comprising a liquid A containing cement, an aggregate having a maximum particle size of 2.5 mm, and a substance containing slaked lime, and a liquid B containing an alkali metal aluminate. 5. From liquid A containing cement, aggregate having a maximum particle size of 2.5 mm, slaked lime-containing substance, and phosphate or organic acid, and liquid B containing alkali metal aluminate. Spray material. 6. A liquid containing cement, an aggregate having a maximum particle size of 2.5 mm, a substance containing slaked lime, fibers, and phosphate or an organic acid, and B containing an alkali metal aluminate. Spray material consisting of liquid. 7. A spraying method, characterized in that the liquid A and the liquid B according to claim 4, 5 or 6 are individually fed under pressure to be cured.