JP4841958B2 - Cement composition, injection material using the same, and method of using the same - Google Patents

Description

  The present invention relates to a cement composition used in the civil engineering / architecture field, and more particularly to a method for effectively using rice husk ash, and is used for applications where the viscosity of cement milk, cement mortar, or concrete needs to be rapidly increased. The present invention relates to a cement composition and a method for using the same.

In tunnel lining, cavities may occur on the back of the lining concrete during and after construction.
If this cavity is left as it is, (1) the ground surface will sink as the ground collapses into the cavity, (2) if the ground collapse is severe, deformation and destruction of the lining concrete, especially tunnels (3) The lining concrete deteriorates due to the inflow of groundwater into the cavity, and (4) The fallen concrete pieces fall into the traveling lane and water leaks from the cracks in the winter season. There was a problem such as the lane freezing.

In recent years, there is a backfill injection method that fills the cavity behind the lining concrete as a tunnel repair work whose number of constructions has increased.
This backfill injection method fills the cavity with an injection material to stabilize the tunnel, and the injection material used here is called a backfill material.
Conventionally, a cement-bentonite system mainly composed of cement and bentonite has been used as this backfilling material, but the fluidity is too large, and the backfilling material unnecessarily escapes to a distant place, If there is, there are problems such as the backfilling material flowing out or being diluted to lower the physical properties.

  Therefore, a method of increasing the viscosity by adding a superabsorbent resin to the main material of cement and bentonite and a method of promoting hardening by adding water glass have been proposed (see Patent Document 1 and Patent Document 2). ).

  However, in any method, it takes time until the viscosity increases, and the method of adding the superabsorbent resin is expensive, and the superabsorbent resin itself is expensive. Since the viscosity of the main material becomes high, there is a problem that the pumping distance has to be shortened and the injection location is limited.

  On the other hand, the method of adding water glass to the main material of cement and bentonite is a strong alkali with a water glass pH of 13 or higher, so the work is considerably restricted, and the elution water from the hardened body has a burden on the environment. There existed problems, such as giving and the long-term strength of a hardening body falling.

  Recently, as a method for solving the problems of backfilling materials, the main material of cement-bentonite and cement-coal ash (fly ash) is instantly plasticized by adding a polymer as a plasticizer, The thing which improved the non-separability and safety | security is proposed (refer patent document 1, patent document 3, and patent document 4).

On the other hand, rice husk ash is one of industrial by-products that is not effectively used. Rice husk ash is an ash obtained by incinerating rice husk, which is an industrial by-product in the agricultural field. Since it contains a lot of SiO ₂ and has pozzolanic reactivity, it has been proposed to use it as a concrete admixture (see Non-Patent Document 1 and Non-Patent Document 2).
However, the utilization situation is still not sufficient, and the landfill is often disposed as it is, and the disposal requires a lot of cost. Therefore, establishment of a further utilization method has been desired.

JP-A-10-237446 Japanese Patent Laid-Open No. 11-061123 JP-A-10-238289 JP 2000-280231 A Annual report of concrete engineering, Vol.22, No.2, pp.139-144, 2000 Annual report of concrete engineering, Vol.22, No.2, pp.145-150, 2000

  The present invention is superior in long-distance pumpability than an injection material using bentonite or a highly water-absorbent resin, and thickens quickly after addition of a plasticizer, for example, a void filler such as a backfill material is far away. There is no need to escape unnecessarily, even if there is spring water, the void filler will not flow out, it will not be diluted and the physical properties will deteriorate, and the elution water will not become a strong alkali like water glass. It is an object to provide a cement composition.

  As a result of various studies, the present inventor has used a specific cement composition to show a sudden increase in viscosity, excellent strength development, non-separability in water, pH value using water glass. As a result, the present invention has been completed by obtaining knowledge that it can be lowered compared with the case where the present invention is present.

That is, the present invention is a cement composition comprising 100 parts of cement, 50 to 300 parts of rice husk ash , 0.2 to 2 parts of an alkali thickened polymer emulsion in terms of solid content, and 200 to 350 parts of water , A cement composition comprising 100 parts of cement, 50 to 300 parts of rice husk ash , 0.2 to 2 parts of an alkali thickened polymer emulsion in terms of solid content, a curing accelerator , and 200 to 350 parts of water , a grout made with the composition, 100 parts of cement, rice husk ash 50-300 parts, and the mixture comprising water 200-350 parts is a liquid, an alkali thickening type polymer emulsion to 100 parts of cement the mixture comprising the 0.2 to 2 parts in terms of solid content against the water and solution B, immediately before use, a use of the cement composition obtained by mixing the liquids a and B, the cement 100 parts, mixed comprising a rice hull ash 50-300 parts, and water of 200 to 350 parts of Was a solution A, the alkali thickening polymer emulsion is a mixture comprising a water 0.2 to 2 parts in terms of solid content relative to 100 parts cement and solution B, contain a curing accelerator and water the mixture of the C solution, just prior to use, a solution is the use of liquid B, and a cement composition comprising a mixture of C solution, mixed immediately before use, a solution, in the order of C solution, and solution B a method of using the cement composition obtained by, 100 parts cement, rice husk ash 50-300 parts, and the mixture comprising water 200-350 parts is a liquid, an alkali thickening type polymer emulsion cement Use of a cement composition obtained by mixing 0.2 to 2 parts in terms of solid content with respect to 100 parts , a hardening accelerator, and water as D liquid, and mixing A liquid and D liquid immediately before use mETHOD Ri der, alkali thickening type polymer emulsion, unsaturated carboxylic acids A polymer emulsion obtained by copolymerization of an ethylenically unsaturated compound and a curing accelerator containing an aluminate and / or sulfate, according to any one of claims 4 to 7. The average particle size of rice husk ash is 6.9 to 10 μm, and the amount of rice husk ash used is 200 to 300 parts with respect to 100 parts of cement. A method for injecting the cement composition having a specific surface area of 32.4 to 200 m ² / g and a rice husk ash density of 2.1 to 2.3 g / cm ³ , wherein the flow value of the cement composition is 90 mm or less, and the cement composition Is a method for injecting the cement composition which is non-separable in water and has no or no turbidity of water .

  By using the cement composition of the present invention, a back-filling with characteristics such as a sudden increase in viscosity, excellent strength development, non-separability in water, and a low pH value compared to when water glass is used. A void filler such as a material is obtained.

Hereinafter, the present invention will be described in detail.
In the present invention, the part is based on mass unless otherwise specified.

  The cement used in the present invention is not particularly limited, and a normal cement can be used. Specifically, various portland cements such as normal, early strength, super early strength, moderate heat, and low heat, and the like. Portland cement, various mixed cements mixed with blast furnace slag, fly ash, or silica, filler cement mixed with fine limestone powder or blast furnace annealed slag fine powder, waste-use cement, so-called eco-cement, etc. One or two or more of these can be used.

The rice husk ash used in the present invention is an ash obtained by incinerating rice husk, which is an agricultural by-product, and has SiO ₂ as a main component and has pozzolanic activity.
Although depending on the incineration conditions, the density of rice husk ash is 2.1 to 2.3 g / cm ³ , the BET specific surface area (hereinafter referred to as BET) is 1 to 200 m ² / g, the average particle size is 1 to 20 μm, and the vitrification rate is 80 to 98. There are many things about%.
The amount of rice husk ash used varies depending on the quality of rice husk ash and cannot be uniquely defined, but generally, 30 to 500 parts are preferable, and 50 to 300 parts are more preferable with respect to 100 parts of cement. . If the amount is less than 30 parts, the viscosity may not increase, the fluidity may increase or the inseparability in water may decrease, and if it exceeds 500 parts, the viscosity becomes too high and mixing of the cement composition is difficult. It may become.
In this invention, 3-10 micrometers is preferable and, as for the average particle diameter of rice husk ash, 5-8 micrometers is more preferable. If it is less than 3 μm, the viscosity of the liquid A containing cement, rice husk ash, and water becomes high, and it may be difficult to pump by the pump. If it exceeds 10 μm, the viscosity does not increase and the fluidity is large. And inseparability in water may be reduced.

  The alkali thickened polymer emulsion (hereinafter referred to as the present emulsion) used in the present invention refers to a polymer emulsion that is thickened by alkali.

Examples of the emulsion include various unsaturated carboxylic acids, ethylenically unsaturated compounds, and copolymers of unsaturated carboxylic acids and ethylenically unsaturated compounds, and the excellent effect of increasing the degree of thickening. In view of the above, a polymer emulsion obtained by copolymerization of an unsaturated carboxylic acid and an ethylenically unsaturated compound is preferred.
Examples of the polymerization method of the unsaturated carboxylic acid and the ethylenically unsaturated compound include a method of copolymerization by emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, or the like.

  Examples of unsaturated carboxylic acids include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, aconitic acid, and crotonic acid, and unsaturated carboxylic acids such as maleic anhydride and citraconic anhydride. Acid anhydrides, and unsaturated carboxylic acid esters such as monomethyl itaconate, monobutyl itaconate, and monoethyl maleate. Among these, unsaturated carboxylic acids are preferred in terms of higher viscosity, and acrylic acid And / or methacrylic acid is more preferred.

  Although it does not specifically limit as an ethylenically unsaturated compound, An acrylate ester monomer and / or a methacrylic acid ester monomer are preferable at the surface which is more excellent in a viscosity. Examples of the acrylic acid ester include methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, and glycidyl acrylate. Methacrylic acid esters include methyl methacrylate, Examples include ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, and glycidyl methacrylate.

  When using a polymer emulsion obtained by copolymerization of an unsaturated carboxylic acid and an ethylenically unsaturated compound, the copolymerization ratio of the unsaturated carboxylic acid and the ethylenically unsaturated compound is higher in terms of viscosity. The acid: ethylenically unsaturated compound is preferably 20: 1 to 1:20, more preferably 5: 1 to 1: 5. Outside this range, good alkali thickening may not be obtained.

  The amount of the emulsion used is preferably 0.1 to 2 parts, more preferably 0.2 to 1 part, in terms of solid content, with respect to 100 parts of cement. If the amount is less than 0.1 part, the thickening effect is reduced, the fluidity is increased, and the inseparability in water may be reduced.

When the hardening of the cement composition is delayed, bleeding (floating water) which is a kind of material separation occurs, and voids may be generated after hardening, resulting in structural defects.
The hardening accelerator used in the present invention promotes hardening of the cement composition to reduce bleeding, suppress formation of voids, and contribute to strength development.

  Examples of curing accelerators include sulfates such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, aluminum sulfate, potassium alum, and iron sulfate, carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate, water Hydroxides such as lithium oxide, sodium hydroxide, magnesium hydroxide, aluminum hydroxide, potassium hydroxide, and calcium hydroxide, chlorides such as calcium chloride, magnesium chloride, and iron chloride, lithium aluminate, sodium aluminate , Aluminates such as potassium aluminate and calcium aluminate, silicates such as lithium silicate, sodium silicate and potassium silicate, amines such as diethanolamine and triethanolamine, calcium formate and calcium acetate Organic acid Calcium salts and colloids such as silica sol and alumina sol can be mentioned, and one or more of these can also be used. Among these, aluminate and / Or sulfates are preferred, and those using aluminates and sulfates are more preferred.

Of the aluminates, calcium aluminate is preferred in terms of curing acceleration and strength development.
Calcium aluminate (hereinafter referred to as CA) is a raw material containing calcia, by mixing raw materials containing alumina obtained by heat treatment such as melting in sintering and electric furnace kiln, CaO and Al ₂ O ₃ is intended to generically compound mainly composed of, as a specific _{example, CaO · 2Al 2 O 3,} CaO · Al 2 O 3, 12CaO · 7Al 2 O 3, 11CaO · 7Al 2 O 3 · CaF 2 , 3CaO · Al ₂ O ₃ , 3CaO · 3Al ₂ O ₃ · CaSO ₄ crystalline calcium aluminates and amorphous compounds mainly composed of CaO and Al ₂ O ₃ Any of them can be used. Among these, an amorphous 12CaO · 7Al ₂ O ₃ composition is more preferable in terms of strength development.
Fineness of the CA, Blaine specific surface area value (hereinafter, referred to as Blaine value) is preferably at least 3,000 cm ² / g in, 5,000 cm ² / g or more is more preferable. If it is less than 3,000 cm ² / g, the initial strength development may be small.

Among the sulfates, calcium sulfate and / or aluminum sulfate are preferable in terms of curing acceleration and strength development.
Examples of calcium sulfate include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. Among these, anhydrous gypsum is preferable in terms of acceleration of hardening and strength development.
Fineness of sulfate is preferably 3,000 cm ² / g or more in Blaine value, 5,000 cm ² / g or more is more preferable. If it is less than 3,000 cm ² / g, strength development may be small.

  When aluminate and sulfate are used in combination as the curing accelerator, the amount of sulfate used is preferably 20 to 500 parts, more preferably 50 to 150 parts, relative to 100 parts of aluminate. If it is less than 20 parts, the initial strength development may be reduced, and if it exceeds 500 parts, the fluidity increases, the inseparability in water decreases, and the long-term strength development may decrease.

  The amount of the curing accelerator used varies depending on the type and cannot be uniquely defined, but generally 1 to 30 parts is preferable and 2 to 20 parts is more preferable with respect to 100 parts of cement. If the amount is less than 1 part, the fluidity increases, the inseparability in water decreases, and the strength development property may decrease. If the amount exceeds 30 parts, the viscosity increases and the pumping distance may decrease.

  The cement composition of the present invention can be used in combination with aggregates such as sand and gravel, water reducing agents, antifreezing agents, and the like.

  The amount of water mixed with cement in the present invention is not particularly limited, but is preferably 150 to 400 parts, more preferably 200 to 350 parts, with respect to 100 parts of cement. If it is less than 150 parts, the kneading of the cement composition may be difficult, and if it exceeds 400 parts, the fluidity may increase and the inseparability in water may decrease.

The cement composition of the present invention is obtained by mixing a cement, rice husk ash, and the present emulsion, or a curing accelerator with them.
Although the mixing method is not particularly limited, a mixture containing cement, rice husk ash, and water is designated as liquid A, and a mixture comprising an alkali-thickened polymer emulsion and water is designated as liquid B. A method of mixing the A liquid and the B liquid immediately before use, and a method of mixing the liquid A, the B liquid, and the C liquid immediately before use with a mixture containing a curing accelerator and water as the C liquid. In particular, immediately before use, a method of mixing liquid A, liquid C, and liquid B in this order, and further, a mixture containing an alkali thickening polymer emulsion, a curing accelerator, and water is liquid D, immediately before use. In addition, it is preferable to rapidly increase the viscosity by a method of mixing the liquid A and the liquid D.

Mixing the emulsion and the curing accelerator with water in advance to form a solution or suspension is preferable from the viewpoint of increasing the viscosity and improving the viscosity.
The amount of water used in this case is not particularly limited. However, when the emulsion is mixed with water in advance, it is preferably diluted with 5 to 20 times the solid content of the emulsion, and a curing accelerator. When water is mixed with water in advance, it is preferably diluted with 1 to 3 times as much water. When the amount of water is less than this, the viscosity may be increased and the mixing property may be reduced, and when the amount of water is increased, the fluidity may be increased and the inseparability in water may be reduced.

In the present invention, when the emulsion and the hardening accelerator are used together, the liquid A of the cement-rice husk ash liquid and the liquid D of the mixture of the emulsion, the hardening accelerator and water are separately pumped, and the nozzle Although it is possible to use it by mixing and mixing at the tip, three types of liquids, cement-rice husk ash liquid A, this emulsion liquid B liquid, and hardening accelerator liquid C liquid, are separately pumped to the nozzle. A method in which the mixture is mixed and mixed at the tip is more preferable.

Moreover, since a hardening accelerator may harden | cure within 1 hour after mixing with water, it is preferable to use a retarder together.
Examples of the retarder include oxycarboxylic acids such as citric acid, tartaric acid, gluconic acid, and malic acid or metal salts such as sodium salt and potassium salt thereof, boric acid, tripolyphosphate, and pyrophosphate. One or two or more of these can be used. Among these, oxycarboxylic acid and / or oxycarboxylate are preferable, and citric acid and / or sodium citrate are more preferable in terms of a large delay effect.
The amount of retarder used is preferably 0.01 to 10 parts, more preferably 0.05 to 5 parts, per 100 parts of cement. If it is less than 0.01 part, the delay effect may be small, and if it exceeds 10 parts, strength development may be reduced.

As a method of merging and mixing the cement composition, a method using a mixing tube such as a Y-shaped tube, a method using a triple tube, and a liquid B of the emulsion and a liquid C of the hardening accelerator are respectively in a shower form. And a method of using an inlet piece for merging and mixing with cement-rice husk ash liquid A.
Moreover, in order to mix a cement composition more uniformly, the method of setting a spiral mixer in the pipe | tube after merging and mixing, and also mixing a cement composition is also mentioned.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

Experimental example 1
The amount of rice husk ash and water shown in Table 1 is mixed with 100 parts of cement using a mixer to prepare solution A, and 0.5 parts of emulsion α and 5 parts of water in terms of solid content are added to 100 parts of cement. Liquid B was prepared by mixing, and C liquid was prepared by mixing 5 parts of hardening accelerator a and 10 parts of water with respect to 100 parts of cement.
The prepared liquid A, liquid C and liquid B were continuously added to the mixer and mixed for 5 seconds, and then the flow value, inseparability in water, and compressive strength were measured. The results are also shown in Table 1.

<Materials used>
Cement: Ordinary Portland cement, commercially available rice husk ash: Incinerated rice husk, SiO ₂ 91.4%, Al ₂ O ₃ 0.7%, Fe ₂ O ₃ 0.2%, CaO 0.2%, density 2.14g / cm ³ , BET 32.4m ² / g, average particle size 6.9μm
Emulsion α: This emulsion, solid content concentration 30%, ethyl acrylate: methacrylic acid = 45: 55 ethyl acrylate / methacrylic acid copolymer emulsion curing accelerator a: 12CaO · 7Al ₂ O ₃ composition, vitrification rate 95%, Equivalent mixture of aluminate with CA of 6,000 cm ² / g of brane and sulfate of anhydrous gypsum with 5,400 cm ² / g of brane

<Measurement method>
Average particle size: Measured with a laser diffraction particle size analyzer Flow value: Measured after mixing for 2 minutes after placing in a cylinder with an inner diameter of 80 mm and a height of 80 mm. Performed according to the underwater separation test in the guideline for design and construction of non-separable concrete underwater, excellent when there is no water turbidity, good when there is little water turbidity, water turbidity is possible but practical In some cases, the material was separated and the turbidity of water was large.
Compressive strength: Measured according to JIS R 5201

Experimental example 2
100 parts of cement, 200 parts of rice husk ash having the average particle size shown in Table 2, and 200 parts of water were mixed with a mixer to prepare liquid A, and the same procedure as in Experimental Example 1 was performed except that the viscosity of liquid A was measured. It was. The results are also shown in Table 2.

<Measurement method>
Viscosity: measured with a B-type rotational viscometer

Experimental example 3
Mix 100 parts of cement, 200 parts of rice husk ash, and 200 parts of water with a mixer to prepare solution A. Mix 100 parts of cement with the emulsion shown in Table 3 and 10 times the amount of water. A liquid B was prepared, and the same procedure as in Experimental Example 1 was conducted except that the liquid C was prepared by mixing 5 parts of the curing accelerator a and 10 parts of water.
For comparison, the same procedure was performed using a non-emulsion having no alkali thickening instead of the present emulsion.
Further, when the B liquid was not used, the A liquid and the C liquid were sequentially added to the mixer and mixed for 5 seconds. The results are also shown in Table 3.

<Materials used>
Emulsion β: This emulsion, solid content concentration 30%, ethyl acrylate: methacrylic acid = 45: 55 ethyl acrylate / methacrylic acid copolymer emulsion 70 parts, ethylene: vinyl acetate = 18: 82 ethylene / vinyl acetate copolymer Polymer emulsion 30 parts of mixture emulsion γ: non-emulsion, solid content concentration 30%, styrene: 2-ethylhexyl acrylate = 45: 55 styrene / 2-ethylhexyl acrylate copolymer polymer emulsion

Experimental Example 4
100 parts of cement, 200 parts of rice husk ash, and 200 parts of water are mixed with a mixer to prepare solution A. To 100 parts of cement, 0.5 part of emulsion α and 5 parts of water are mixed in terms of solid content. The same procedure as in Experimental Example 1 was conducted except that the solution C was prepared by mixing the hardening accelerator shown in Table 4 with 100 parts of cement, twice the amount of water, and 0.1 part of the retarder. went.
In addition, when not using C liquid, it injected into the mixer in order of A liquid and B liquid, and it kneaded for 5 seconds. The results are also shown in Table 4.

<Materials used>
Curing accelerator b: sulfate, aluminum sulfate, commercial product curing accelerator c: carbonate, sodium carbonate, commercial product curing accelerator d: hydroxide, calcium hydroxide, commercial product curing accelerator e: aluminate, Sodium aluminate, commercial curing accelerator f: colloid, silica sol, commercial product retarder: citric acid, commercial product

  By using the cement composition of the present invention, it has a characteristic that it shows a sudden increase in viscosity, is excellent in strength development, has inseparability in water, and has a low pH value compared to when water glass is used. Therefore, there are gap fillers such as backfill materials for cavities and gaps in natural ground, fillers for shield segments, and instantaneous setting injection materials in double-pipe single-phase or double-phase injection methods. It is useful for applications that require a sudden increase in the viscosity of cement milk, cement mortar, or concrete, such as sealing materials and primary injection materials in the double pipe double packer method.

Claims (10)

A cement composition comprising 100 parts of cement, 50 to 300 parts of rice husk ash , 0.2 to 2 parts of an alkali thickening polymer emulsion in terms of solid content, and 200 to 350 parts of water . A cement composition comprising 100 parts of cement, 50 to 300 parts of rice husk ash , 0.2 to 2 parts of an alkali thickened polymer emulsion in terms of solid content, a curing accelerator , and 200 to 350 parts of water . An injection material comprising the cement composition according to claim 1 or 2 . A mixture containing 100 parts of cement, 50 to 300 parts of rice husk ash, and 200 to 350 parts of water is designated as liquid A, and the alkali thickening polymer emulsion is 0.2 to 2 parts in terms of solid content with respect to 100 parts of cement. A method for using a cement composition comprising a mixture containing water as a B liquid and mixing the A liquid and the B liquid immediately before use. A mixture containing 100 parts of cement, 50 to 300 parts of rice husk ash, and 200 to 350 parts of water is designated as liquid A, and the alkali thickening polymer emulsion is 0.2 to 2 parts in terms of solid content with respect to 100 parts of cement. Cement composition comprising a mixture containing water as liquid B, a mixture containing a curing accelerator and water as liquid C, and mixing liquid A, liquid B and liquid C immediately before use. How to use things. The method of using a cement composition according to claim 5 , wherein the liquid A, the liquid C, and the liquid B are mixed in this order immediately before use. A mixture containing 100 parts of cement, 50 to 300 parts of rice husk ash, and 200 to 350 parts of water is designated as A liquid, and 0.2 to 2 parts in terms of solid content of the alkali thickening polymer emulsion with respect to 100 parts of cement . A method of using a cement composition obtained by mixing a hardening accelerator and water as a D liquid and mixing the A liquid and the D liquid immediately before use. 5. The alkali thickening polymer emulsion is a polymer emulsion obtained by copolymerization of an unsaturated carboxylic acid and an ethylenically unsaturated compound, and the curing accelerator contains an aluminate and / or sulfate. A method for injecting a cement composition according to claim 7. The average particle size of rice husk ash is 6.9 to 10 μm, the amount of rice husk ash used is 200 to 300 parts per 100 parts of cement, and the BET specific surface area of rice husk ash is 32.4 to 200 m. ² / g, density of rice husk ash 2.1-2.3g / cm ^Three The method for injecting a cement composition according to any one of claims 4 to 8. The flow value of the cement composition is 90 mm or less, the cement composition is non-separable in water and has no turbidity of water or slight turbidity of water. A method for injecting the described cement composition.