JPH11335152A - Cement-based material and its spray application - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the spray application of a cement-based material having excellent initial hardenability under the employment of an alkali-free liquid quick setting agent. SOLUTION: This method for the spray application of a cement-based material comprises spraying the cement-based material using an alkali-free liquid quick setting agent. Therein, the cement-based material comprises a hydraulic composition comprising gypsum and a calcination product which is obtained by calcining a raw material comprising one or more kinds of municipal refuse incinerated ash and sewage sludge incinerated ash and which contains 10-40 wt.% of one or more kind of C11 H7 CaCl2 and C3 A and one or more kinds of at least C2 S and C3 S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of spraying a cement-based material such as mortar or concrete on a ceiling or a wall in the construction of a tunnel or an underground structure, and more particularly, to a method of spraying an alkali-free liquid quick-setting agent. The present invention relates to a spraying method and a spray material having improved initial quick-setting properties when used.

[0002]

2. Description of the Related Art Conventionally, as a lining method for tunnels and underground structures, a spraying method in which mortar or concrete is directly sprayed onto a construction surface without using a form using a quick-setting agent and compressed air. It has been known. In this spraying method,
(i) a dry method in which cement, fine aggregate, coarse aggregate and quick-setting agent are mixed in advance, and water is added to the mixed powder before the nozzle and sprayed, (ii) cement, fine aggregate, coarse aggregate and water Is kneaded into a ready-mixed concrete, to which a quick-setting agent is added just before the nozzle (Japanese Patent Laid-Open No. 61-92263). In both the dry method and the wet method, as a quick-setting agent to be used, an alkali-based quick-setting agent containing a large amount of an alkali component and a quick-setting agent containing substantially no alkali (alkali-free quick-setting agent). It has been known. Generally, the alkali content of the alkali-free quick setting agent is generally less than 2% by weight.

As the alkaline quick-setting agent, water glass (sodium silicate), sodium aluminate, calcium aluminate to which an alkali salt such as sodium carbonate is added, and the like are generally used. However, since these are strongly alkaline, during spraying work, workers' skin,
It has been reported to have adverse effects on respiratory organs, eyes, etc.
In addition, it has been pointed out that alkali is eluted from concrete after curing and is mixed into well water or the like, thereby contaminating the surrounding environment. Furthermore, when a large amount of alkali metal ions are mixed in concrete, there is a problem that the long-term strength development of concrete is impaired, and the durability of concrete is reduced by an alkali-aggregate reaction.

In order to solve such a problem, an alkali-free quick-setting agent has been proposed. Alkali-free quick-setting agents are classified into a powdery form and a liquid form. As the powdery form, a calcium sulfoaluminate compound is known. However, this quick-setting agent has an initial quick-setting performance lower than that of an alkaline type, and in order to obtain sufficient quick-setting property, it is necessary to use an amount nearly twice that of an alkaline type quick-setting agent, for example, about 10% or more based on cement. It has been pointed out that the use of such a large amount of the powdery material increases dust and causes deterioration of the working environment, and that it is difficult to add a predetermined amount stably.

As liquid alkali-free quick-setting agents, aluminum sulfate and silica sol compounds have been proposed. These liquid types are regarded as promising because they generate little dust, can be added stably, and are easy to handle, and some of them have been used. However, these existing alkali-free liquid quick-setting agents still have insufficient initial quick-setting performance, and for practical use, it is necessary to enhance the initial curing performance within a few minutes after mixing of the quick-setting agent.

On the other hand, in recent years, general waste and industrial waste such as municipal waste and sewage sludge have increased remarkably, and their effective use and recycling have been attempted in various fields. There is no way, and it currently relies on landfills. However, recently, in the field of cement production, cement (hereinafter referred to as “ecocement”) made from municipal waste incineration ash, sewage sludge incineration ash, or the like has been manufactured. I have.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the conventional spraying method using an alkali-free quick-setting agent, and exhibits excellent curing performance in a short time at the beginning of spraying. In addition, it is an object of the present invention to provide a cement-based material capable of promoting effective use and recycling of eco-cement manufactured from waste through expansion of uses thereof and a spraying method thereof.

[0008]

That is, the present invention relates to (1) a method of spraying cement-based material using an alkali-free liquid quick-setting agent, in which municipal waste incineration ash and sewage sludge incineration ash are used as cement-based materials. A fired product using at least one of C ₁₁ A ₇ CaCl ₂ and C ₃ A as a raw material.
0-40% by weight and at least C ₂ S, about spray construction method of the cement-based material, which comprises using the C ₃ hydraulic composition comprising a fired product and gypsum comprising one or more S.

The spraying method according to the above (1), wherein (2) the alkali-free liquid quick-setting agent is a quick-setting agent containing aluminum sulfate as a main component, (3) an alkali-free liquid quick-setting agent, The spraying method according to the above (1), wherein the liquid quick-setting agent is a quick-setting agent containing aluminum sulfate and a silica component as main components.

[0010] The present invention also provides (4) a spraying material obtained by blending a cement-based material with a quick setting agent, wherein at least one of municipal waste incineration ash and sewage sludge incineration ash is used as the cement-based material. And a fired product comprising: C ₁₁ A ₇ CaC
l _2, C ₃ 10 to 40 wt% of one or more of A, and at least C ₂ using S, C ₃ hydraulic composition comprising a fired product and gypsum comprising one or more S a (Ecocement), quick- The present invention relates to a cement-based spraying material characterized by using an alkali-free liquid quick-setting agent as an agent.

The spraying material of the present invention is (5) a spraying material used in a shoring operation or a spraying operation using a steel fiber, and is a low chlorine type cement material containing C ₃ A as a constituent. The cement-based spraying material of (4) using ecocement is included.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically.
The present invention improves the initial hardening properties by using eco-cement as a cement-based material for mortar or concrete in spraying construction using an alkali-free liquid quick-setting agent as a cement-based material.
Ecocement is made from more than one kind of municipal garbage incineration ash, such as sewage sludge dry powder in which quicklime is mixed with shells and sewage sludge, other general waste and industrial waste, and sewage sludge incineration ash.
If necessary, limestone, which is an ordinary cement raw material,
Raw materials whose components are adjusted by mixing clay, silica, aluminum ash, bauxite, iron, etc. are used.
The clinker obtained by baking at 500 ° C. is mixed with gypsum and pulverized, or the clinker alone is pulverized and mixed with gypsum as necessary.

Ecocement is a mineral component derived from aluminum and chlorine contained in the raw material, for example, 11CaO.
・ 7Al ₂ O ₃ .CaCl ₂ (abbreviated as C ₁₁ A ₇ CaCl ₂ ), 3C
aO.Al ₂ O ₃ (abbreviated as C ₃ A). Besides, 2CaO.SiO contained in ordinary cement
₂ (abbreviated as C ₂ S), 3CaO.SiO ₂ (abbreviated as C ₃ S)
More than species.

[0014] The present invention relates to a method for producing C ₁₁ A as a cement-based material.
₇ CaCl ₂ to C ₃ A in an amount of 10 to 40% by weight
Use the contained eco-cement. When the content of these aluminum compounds is less than 10% by weight, the reactivity with the liquid quick-setting agent component is low, and sufficient quick-setting property cannot be obtained. This aluminum source is mainly derived from incineration ash. Therefore,
When the content of the aluminum compound is less than 10% by weight, the amount of incinerated ash used is small, which is not preferable from the viewpoint of promoting effective use of waste and recycling. On the other hand, when the content of the aluminum compound exceeds 40% by weight, the progress of hydration becomes remarkable, the spraying material may expand excessively, and the development of long-term strength is unfavorably inhibited.

[0015] As described above, ecocement contains a larger amount of aluminum compound than ordinary portland cement. In addition, a type in which C ₁₁ A ₇ .CaCl ₂ having a composition in which the chlorine component of the raw material is positively incorporated is used as a component, and a component in which C ₃ A in which most of the chlorine component is removed in the firing step is used as a component. The low chlorine type is known. Any of the present inventions can be used depending on the conditions of use.

When using shoring and steel fiber for the construction of shotcrete, low chlorine type eco-cement containing C ₃ A as a component is preferred from the viewpoint of suppressing the generation of rust. preferable.

As the gypsum added to the clinker of the ecocement, any of anhydrous gypsum, hemihydrate gypsum and gypsum can be used. Preferably, SO ₃ / Al ₂
It is preferable to add O _{3 so that} the molar ratio of O ₃ is in the range of 0.3 to 1.5. If the amount of gypsum is out of this range, sufficient strength cannot be obtained, or inconvenience may occur in construction.

The cement-based spraying material of the present invention may be one obtained by adding other hydraulic materials to ecocement. For example, ordinary, early strength, moderate heat, sulfate resistant etc. Portland cement, mineral ash fine powder fly ash, blast furnace slag fine powder, silica fume, limestone fine powder, silica, volcanic ash, diatomaceous earth mixed cement Alternatively, a fast-setting cement to which an aluminate mineral is added may be added. The mixing amount of hydraulic materials other than this ecocement is
It is appropriate that the amount of one or more of C ₁₁ A ₇ CaCl ₂ to C ₃ A is 10 to 40% by weight in the whole spray material.

The quick-setting agent used in the spraying method of the present invention is an alkali-free liquid quick-setting agent.
Alkali components such as ₂ O and K ₂ O are 1% by weight in terms of Na ₂ O
These are: In particular, liquid quick-setting agents containing aluminum sulfate as a main component are compatible with Ecocement, and when used in combination with Ecocement, significantly increase the initial quick-setting force, which is a disadvantage of alkali-free liquid quicksetting agents. Can be.

Further, the aluminum sulfate-based liquid quick setting agent more preferably contains a silica component together with aluminum sulfate. This silica component is
₂ S, to promote the formation of C-S-H due to hydration of C ₃ S component contributes to the promotion of medium- and long-term strength.

The silica component may be silica fume, precipitated silica, or a silica compound such as aluminosilicate, smectite or mectite-type magnesium silicate, and a mixture thereof. Here, the silica component preferably contains precipitated silica. Precipitated silica is a precipitate of silica produced by reacting an alkali metal silicate with an acid (generally an inorganic acid). This precipitated silica has good reactivity and contributes more effectively by promoting the medium- to long-term strength.

In the spraying method of the present invention, except that ecocement is used as a spraying material, a general method using a liquid quick-setting agent can be directly used. That is, mortar / concrete using eco-cement is manufactured, and the mortar / concrete is pumped by a hose by a pump, and a liquid quick-setting agent is injected in the middle of the hose at a pressure higher than the pressure of the concrete. From the viewpoint of uniform dispersion during injection,
It is preferred to inject from several places in the hose. The injection portion of the quick setting agent is preferably in a range of 1 to 10 m from the tip of the nozzle. Further, the present invention can be carried out not only by the wet method but also by a dry method. When producing a mortar / concrete spraying material using ecocement, there is no problem in using various commercially available dispersants in combination.

[0023]

Examples and Comparative Examples Hereinafter, the present invention will be specifically described with reference to Examples. Note that the present invention is not limited to these.

Example 1 Concrete was manufactured by using the ecocement shown in Table 1 and mixing each material so as to have a concrete composition shown in Table 2, and a spray test was conducted. The fine aggregate used was land sand from Ogasa, and the coarse aggregate used was crushed hard sandstone from Iwase. The dispersant used was a naphthalene sulfonate / formalin condensate. The alkali-free liquid quick setting agent contains 30% by weight of aluminum sulfate as an active ingredient (setting agent A),
Two types, one containing 25% by weight of aluminum sulfate and 10% by weight of precipitated silica (accelerator B), were used. For comparison, a case where ordinary Portland cement (made by Chichibu Onoda) was used as the cement is shown in comparison.

In the test, the kneaded concrete spraying material was pumped by a pump, and 10% by weight of an alkali-free liquid quick-setting agent was added to the cement 3 m before the spraying nozzle, and sprayed on a pull-out test dish and a wooden box. Was performed. As an evaluation of the hardening performance of the sprayed concrete, a pull-out test was performed for the material age of 3, 24 hours after the setting was completed, and the compressive strength was measured for the material age of 28 and 91 days.
The spraying properties immediately after the addition of the quick setting agent were evaluated visually and by touch. Table 3 shows the evaluation results of the concrete.

Using eco-cement (Sample No. 1,
In 2), the spraying properties were good, and the 3-hour strength of the material showed a much higher value than the comparative sample (No. 3) using ordinary cement. The strength after 28 days of material tended to be sluggish, but it was confirmed that the use of quick-setting binder B containing a silica component had an effect of improving long-term strength. On the other hand, in the comparative sample using ordinary cement, the hardening strength immediately after spraying was significantly low, and although it adhered, the hardening was insufficient, so a phenomenon was observed in which concrete was peeled off when sprayed thickly on the ceiling.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

According to the spraying method of the present invention, even when an alkali-free liquid quick-setting agent is used, a spraying effect with excellent initial quick-setting properties after spraying can be obtained. In addition, the effective use and recycling of eco-cement produced from waste can be promoted through expansion of uses.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // (C04B 28/02 22:14 7:28)

Claims (5)

[Claims] 1. A fired material comprising, as a raw material, at least one of municipal garbage incineration ash and sewage sludge incineration ash as a cement-based material in spraying of a cement-based material using an alkali-free liquid quick-setting agent. , C ₁₁ A ₇ CaCl ₂ , C ₃
10 to 40% by weight of at least one of A, and at least C
_A method for spraying cement-based materials, comprising using a hydraulic composition comprising a calcined product containing at least one of ₂ S and C ₃ S and gypsum. 2. The spraying method according to claim 1, wherein the alkali-free liquid quick-setting agent is a quick-setting agent containing aluminum sulfate as a main component. 3. The spraying method according to claim 1, wherein the alkali-free liquid quick-setting agent is a quick-setting agent containing aluminum sulfate and a silica component as main components. 4. A sprayed material obtained by mixing a quick-setting agent with a cement-based material, wherein the cement-based material is a fired material using at least one of municipal waste incineration ash and sewage sludge incineration ash as a raw material. , C ₁₁ A ₇ CaCl ₂ , C ₃ A in an amount of 10 to 40% by weight, and at least one of C ₂ S and C ₃ S.
A cement-based spraying material characterized by using a hydraulic composition (ecocement) comprising a calcined product containing at least one or more species and gypsum, and using an alkali-free liquid quick-setting agent as a quick-setting agent. 5. A spraying material used in a shoring work or a spraying work using steel fiber, wherein a low chlorine type eco-cement containing C ₃ A as a constituent component is used as a cement material. Cement-based spraying material.