JP2006143539A - Cement composition, cavity filling material and its using method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement composition for which industrial wastes can be utilized effectively and which has effects such as quick viscosity increase, excellent strength development, an underwater inseparable property and the like and to provide a cavity filling material and its using method. <P>SOLUTION: The cement composition involves cement, slag whose content is 25 pts. or more to 100 pts. of cement, a plasticizer which is an alkali-thickener type polymer emulsion and a curing accelerator. The cavity filling material involves the cement composition. In the using method of the cavity filling material, a liquid A in which the cement, the slag and water are premixed and a liquid B in which the plasticizer and water are mixed are mixed just before use. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cement composition used in the field of civil engineering / architecture, a cavity filler, and a method of using the cement composition, and more particularly to cement milk and mortar using the cement composition in a backfill material for a cavity or void in a natural ground. The present invention relates to a cement composition, a cavity filler, and a method of using the same, which are used for applications in which the viscosity of concrete needs to be rapidly increased.

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, and (2) if the ground collapse is severe, deformation or destruction of the lining concrete, especially in the tunnel Collapse occurs, (3) The lining concrete deteriorates due to the inflow of groundwater into the cavity, and (4) The winter traveling lane freezes due to the fall of the degraded concrete piece to the traveling lane and the leakage from the cracked part. There were issues such as.

In recent years, tunnel repair work, where the number of constructions has been increasing, includes a backfill injection method that fills the cavity behind the lining concrete with an injection material.
The backfill injection method is to fill the cavity with an injection material to stabilize the tunnel, and the injection material used here is called a backfilling material.
Conventionally, cement-bentonite has usually been used as this backfilling material, but the fluidity is too high and the backfilling material unnecessarily escapes to a distant place or if there is spring water, the backfilling material flows out. Or diluted, resulting in a decrease in physical properties.

Therefore, a method of increasing the viscosity by adding a highly water-absorbent resin to the main material of cement and bentonite and a method of promoting hardening by adding water glass have been proposed (see Patent Documents 1 and 2).
However, in either method, it takes time until the viscosity increases, and the method of adding a highly water-absorbing resin is expensive in itself. There is a problem that the viscosity of the material is high, the pumping distance has to be shortened, and the construction is limited, while the method of adding water glass is a strong alkali with a pH value of water glass of 13 or more However, there are problems such as considerably limited work, elution water from the cured body imposes a burden on the environment, and the long-term strength of the cured body decreases.

  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-separation property and safety | security is proposed (refer patent document 1, patent document 3, and patent document 4). ]

On the other hand, there is coal gasification slag as a by-product generated in coal gasification combined power generation, and application to cement compositions has been proposed (Patent Documents 5 to 8).
However, the actual situation is that the utilization method of coal gasification slag has not been established yet.

JP-A-10-237446 Japanese Patent Laid-Open No. 11-061123 JP-A-10-238289 JP 2000-280231 A JP-A-11-139860 JP-A-12-302517 Japanese Patent Laid-Open No. 14-121064 Japanese Patent Laid-Open No. 14-154862

  As a result of repeated studies, the present inventor has used a specific cement composition to show a sudden increase in viscosity, excellent strength development, non-separability in water, and pH value using water glass. The present invention has been completed with the knowledge that it can be made lower than in the case of the present invention.

  The present invention is a cement composition comprising cement, coal gasification slag, and a plasticizer, wherein the coal gasification slag is 25 parts or more per 100 parts of cement, The cement composition, wherein the plasticizer is an alkali thickened polymer emulsion, and the alkali thickened polymer emulsion is a polymer emulsion obtained by copolymerization of an unsaturated carboxylic acid and an ethylenically unsaturated compound. The cement composition containing a hardening accelerator, and a hollow filler containing the cement composition, wherein the cement, coal gasification slag, and water are mixed in advance to form liquid A. This is a method of using a hollow filler in which a plasticizer and water are mixed to form a liquid B, and the liquid A and the liquid B are mixed immediately before use.

Hereinafter, the present invention will be described in detail.
In the present invention, “parts” and “%” are based on mass unless otherwise specified.

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

The coal gasification slag used in the present invention (hereinafter referred to as the present slag) is a by-product generated from a coal gasification furnace in the combined coal gasification power generation, and is vitreous.
The average value of the chemical composition of this slag is SiO ₂ 65-75%, Fe ₂ O ₃ 1-4%, Al ₂ O ₃ 10-17%, CaO 8-12%, MgO 0.1-1%, Na ₂ O 0.1-1%, K ₂ O 0.1-1%, and SO ₃ 0.2% or less.
The fineness of the slag is preferably from 2,000 to 9,000 cm ² / g, more preferably from 3,000 to 8,000 cm ² / g in terms of the specific surface area of the brain (hereinafter referred to as the “brane value”). If it is less than 2,000 cm ² / g, the strength development is not sufficient, and it is uneconomical to grind it to exceed 9,000 cm ² / g.
The amount of slag used depends on the type and quality of the slag and cannot be uniquely defined, but generally 25 to 300 parts are preferable with respect to 100 parts of cement, and 50 to 200 parts. More preferred. If it is less than 25 parts, the viscosity does not increase, the flow becomes large, and the inseparability in water may deteriorate, and if it exceeds 300 parts, the strength expression may deteriorate.

  The plasticizer used in the present invention is a material that transforms a fluid suspension containing cement as a main material into plastic solidification, and specifically includes water glass, aluminum salt, clay mineral, high water absorption. Examples thereof include alkaline polymers and alkali-thickened polymer emulsions. Of these, alkali-thickened polymer emulsions are preferred from the viewpoint of rapid action, economy, and safety.

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

Examples of the emulsion include various unsaturated carboxylic acids, copolymers of unsaturated carboxylic acids and ethylenically unsaturated compounds, and the like. Polymer emulsions obtained by copolymerization of saturated compounds are preferred.
Examples of the polymerization method of the unsaturated carboxylic acid and the ethylenically unsaturated compound include a method of copolymerization by a method such as emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization.

  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 half-esters such as monomethyl itaconate, monobutyl itaconate, and monoethyl maleate are mentioned, and among these, unsaturated carboxylic acids are preferred in terms of showing more excellent effects, Acrylic acid and / or methacrylic acid are more preferred.

  Examples of ethylenically unsaturated compounds include ethylene, cyanovinyl monomers such as acrylonitrile and methacrylonitrile, acrylic acid ester monomers such as methyl acrylate, ethyl acrylate, and butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and hydroxyethyl. Methacrylic acid ester monomers such as methacrylate and glycidyl methacrylate, C3-18 aliphatic carboxylic acid vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl octylate, and neodecanoic acid vinyl ester, Vinyl ether monomers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, and phenyl vinyl ether; Such polyfunctional vinyl monomers such as methacrylate and the like, of which, in terms of showing the superior effects, ester monomers and / or methacrylic acid ester monomers of acrylic acid are preferred.

  The copolymerization ratio of unsaturated carboxylic acids and ethylenically unsaturated compounds in the emulsion is preferably unsaturated carboxylic acids: ethylenically unsaturated compounds = 20: 1 to 1:20, in view of more excellent effects. : 1-1: 5 is more preferable. 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 flow becomes large, and the inseparability in water may be deteriorated.

  In the present invention, from the viewpoint of strength development and material separation resistance, for example, it is preferable to use a curing accelerator containing aluminate and sulfate together.

  Here, examples of the aluminate include lithium aluminate, sodium aluminate, potassium aluminate, and calcium aluminate, and calcium aluminate is preferable in terms of strength development.

Calcium aluminate is a mixture of a raw material containing calcia and a raw material containing alumina, and is obtained by calcining in a kiln or heat treatment such as melting in an electric furnace, and CaO and Al ₂ O ₃ Is a general term for substances having hydration activity, and part of CaO and / or Al ₂ O ₃ is an alkali metal oxide, an alkaline earth metal oxide, silicon oxide, titanium oxide, iron oxide, These are solid substances that are substituted with alkali metal halides, alkaline earth metal halides, alkali metal sulfates, alkaline earth metal sulfates, etc., or those containing CaO and Al ₂ O ₃ as main components. It is a dissolved substance. The mineral form may be either crystalline or amorphous.
Among these, amorphous calcium aluminate is preferable in terms of reaction activity, and amorphous calcium aluminate obtained by quenching the heat-treated product corresponding to the 12CaO · 7Al ₂ O ₃ composition is more preferable.
The particle size of the calcium aluminate 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, the initial strength development may decrease.
In the present invention, halogens such as Cl and F may be contained as long as the object of the present invention is not impaired.
In the present invention, calcium aluminate is not used in combination with sulfate, and can be used alone as a plasticizing aid for the emulsion.

Examples of the sulfate include lithium sulfate, sodium sulfate, magnesium sulfate, potassium sulfate, potassium alum, calcium sulfate, aluminum sulfate, and iron sulfate. In terms of strength development, calcium sulfate and / or aluminum sulfate is preferable. .
Examples of calcium sulfate include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. Among these, anhydrous gypsum is preferable in terms of strength development.
The particle size of the sulfate is preferably from 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 reduced.

  The blending ratio of the aluminate and the sulfate is preferably 20 to 500 parts, more preferably 50 to 150 parts, with respect to 100 parts of the aluminate. If it is less than 20 parts, the strength development may be reduced, and if it exceeds 500 parts, the flow becomes large, the inseparability in water deteriorates, and the long-term strength development may be reduced.

  The amount of the curing accelerator used is preferably 1 to 30 parts, more preferably 2 to 20 parts, relative to 100 parts of cement. If the amount is less than 1 part, the flow may increase, the inseparability in water may deteriorate, the strength development may decrease, and if it exceeds 30 parts, the long-term strength may decrease.

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

  The amount of water mixed with cement in the present invention is not particularly limited, but is preferably 100 to 250 parts, more preferably 150 to 200 parts, with respect to 100 parts of cement. If it is less than 100 parts, the kneading of the cavity filler may be difficult, and if it exceeds 250 parts, the flow becomes large and the inseparability in water may deteriorate.

The cavity filler of the present invention is obtained by mixing cement, the present slag, and the present emulsion.
The method for mixing the hollow filler is not particularly specified, but the cement liquid obtained by mixing cement and the present slag with water in advance is used as the liquid A, and the present emulsion liquid obtained by mixing the present emulsion and water is used. A method in which the viscosity is rapidly increased by mixing the liquid A and the liquid B immediately before use is preferable.
In addition, mixing this emulsion with water in advance to form a solution or suspension is preferable from the standpoint of increasing the viscosity and improving the viscosity.

In actual use, the emulsion and the curing accelerator are preferably mixed with water from the viewpoint of easy addition and mixing.
The amount of water used in that case is not particularly limited, but in the case of this emulsion, it is preferable to dilute with 5 to 20 times the solid content of this emulsion, and in the case of a curing accelerator, It is preferable to dilute 1 to 3 times. If the amount of water is less than this, the viscosity may increase and the mixing property may deteriorate, and if the amount of water increases, the dilution effect of the diluted water increases and the inseparability in water may deteriorate.

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

  The hollow filler and the injection method of the present invention can effectively use industrial waste, exhibit a rapid increase in viscosity, have excellent strength, and have excellent performance such as inseparability in water. I understand that.

  EXAMPLES Hereinafter, although the Example of this invention is shown and this invention is demonstrated further, this invention is not limited to these.

The slag shown in Table 1 and water were kneaded with a mixer with respect to 100 parts of cement to prepare agent A.
Next, 100 parts of cement is mixed with 0.5 part of emulsion α and 5 parts of water in terms of solid content to prepare B agent. Into A agent, B agent is added and kneaded for 5 seconds to prepare a kneaded product. did.
The prepared kneaded product was measured for flow, inseparability in water, and compressive strength. The results are also shown in Table 1.
For comparison, a similar experiment was performed using bentonite instead of the slag. The results are also shown in Table 1.

<Materials used>
Cement: Ordinary Portland cement, commercial slag A: Brain value 2,000cm ² / g, loss on ignition 50%, SiO ₂ 36%, Fe ₂ O ₃ 1.5%, Al ₂ O ₃ 6%, CaO 1.5%, MgO 3%, Na ₂ O 0.2%, K ₂ O 0.5%, SO ₃ 0.4%
This slag B: This slag A ground product, brain value 3,000cm ² / g
This slag C: This slag A ground product, brain value 4,000cm ² / g
This slag D: This slag A ground product, brain value 6,000cm ² / g
This slag E: This slag A ground product, Brain value 8,000cm ² / g
Slag F: Slag A pulverized product, Brain value 9,000cm ² / g
Emulsion α: This emulsion, solid content concentration 30%, ethyl acrylate / methacrylic acid = 45/55 ethyl acrylate / methacrylic acid copolymer polymer emulsion Bentonite: Commercial product

<Measurement method>
Flow: Put the kneaded material into a cylinder with an inner diameter of 80mm and a height of 80mm, and measure the spread after pulling out the cylinder after 2 minutes. The water turbidity is excellent, the water turbidity is slightly good, the water turbidity is practical but possible, and the material is separated and the water turbidity is large. Compressive strength in case of: Measured according to JIS R 5201

100 parts of cement, 200 parts of the present slag shown in Table 2 and 150 parts of water are kneaded with a mixer to prepare agent A. The amount of emulsion shown in Table 2 in terms of solid content and emulsion for 100 parts of cement, and emulsion The same procedure as in Example 1 was conducted except that the B agent was mixed with 10 times the amount of water. The results are also shown in Table 2.
For comparison, a similar experiment was conducted using a non-emulsion without alkali thickening instead of the emulsion. The results are also shown in Table 2.

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

  100 parts of cement, 300 parts of this slag C and 150 parts of water are kneaded with a mixer to prepare agent A, and 0.1 part of emulsion α in terms of solid content and 10 times the amount of water as emulsion with respect to 100 parts of cement. Are mixed to make B agent, and 100 parts of cement is mixed with the amount of curing accelerator shown in Table 3 and 10 times the amount of water as the hardening accelerator to make C agent. , And the same procedure as in Example 1 except that the C agent was kneaded. The results are also shown in Table 3.

<Materials used>
Curing accelerator: in 12CaO · 7Al ₂ O ₃ amorphous quenched with corresponding heat-treated product to the composition, and Blaine 6,000 ² / g calcium 4 parts aluminate, Blaine 5,400cm ² / g of anhydrous gypsum 1 part mixture

Claims (7)

  A cement composition comprising cement, coal gasification slag, and a plasticizer.   The cement composition according to claim 1, wherein the coal gasification slag is 25 parts or more with respect to 100 parts of cement.   The cement composition according to claim 1 or 2, wherein the plasticizer is an alkali thickening polymer emulsion.   The cement composition according to claim 3, wherein the alkali-thickening polymer emulsion is a polymer emulsion obtained by copolymerization of an unsaturated carboxylic acid and an ethylenically unsaturated compound.   Furthermore, the cement composition of one of Claims 1-4 containing a hardening accelerator.   A hollow filler comprising the cement composition according to claim 1.   Cement, coal gasification slag, and water are mixed in advance to form liquid A, plasticizer and water are mixed to form liquid B, and liquid A and liquid B are mixed immediately before use. Item 7. A method for using the hollow filler according to Item 6.