JP6030438B2 - Spraying material and spraying method using the same - Google Patents

Description

The present invention relates to a spray material that is sprayed on underground surfaces such as roads, railways, tunnels such as water conduits, underground structures such as underground domes, and ground surfaces exposed on slopes.

Conventionally, as a lining method for tunnels and underground structures, a spraying method in which mortar and concrete are directly sprayed onto the construction surface without using a formwork using a quick-setting agent and compressed air is known. . In this spraying method, cement, fine aggregate, coarse aggregate, and quick setting agent are mixed in advance, and then this mixed powder is sprayed with water added before the nozzle, and cement, fine aggregate, coarse aggregate In addition, there is a wet construction method in which raw concrete is kneaded with water and a quick setting agent is added to this before the nozzle (see Patent Document 1).
In both the dry method and the wet method, as the quick setting agent to be used, an alkali quick setting agent containing a large amount of an alkali component, and a quick setting agent substantially free of 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 wt%.

  As the alkaline accelerating agent, water glass (sodium silicate), sodium aluminate, calcium aluminate to which an alkali salt such as sodium carbonate is added are generally used. However, since these are strongly alkaline, they have been reported to adversely affect the skin, respiratory organs, eyes, etc. of workers during spraying work. In addition, it has been pointed out that the alkali is eluted from the concrete after hardening and mixed into well water, etc., and pollutes the surrounding environment. Furthermore, when a large amount of alkali metal ions is mixed into the concrete, there is a problem that the long-term strength developability of the concrete is hindered and the durability of the concrete is lowered due to the alkali aggregate reaction.

In order to solve such problems, alkali-free quick setting agents have been proposed. There are two types of alkali-free quick setting agents, powder and liquid, and calcium sulfoaluminate compounds are known as powders. However, this quick setting agent has an initial quick setting performance lower than that of the alkali type, and in order to obtain sufficient quick setting properties, it is necessary to use an amount nearly ten times as high as that of the alkali type quick setting agent, for example, cement. The use of a large amount of such a powdery material increases dust and causes a worsening of the working environment, and it is difficult to add a predetermined amount stably, and there is a concern that the hardened concrete is inhomogeneous.

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

On the other hand, in recent years, municipal waste and sewage sludge and other general waste and industrial waste have increased remarkably, and their effective use and recycling have been attempted in various directions, but there is no definitive method for waste treatment. The current situation depends on landfill. Recently, however, cement (eco-cement) made from municipal waste incineration ash, sewage sludge incineration ash, or the like has been manufactured and is expected to be used effectively.

Then, the spray construction method using an alkali-free liquid quick setting agent, Comprising: The spray construction method using eco-cement as a cement-type material is proposed (refer patent document 2).
According to the proposal, the combination of ecocement, aluminum sulfate, and an alkali-free liquid quencher mainly composed of a silica component has been described as having high strength development from the very beginning. Formulation of (for example, fly ash, fast-hardening cement added with aluminate mineral, etc.) is specified. However, specific substances and blending ratios are not described as in the present invention. For example, even in a section where the construction site has deteriorated natural ground such as spring water, a material that is not different from a normal spray material. The proposal was awaited.
When mortar and concrete using eco-cement have a high water-cement ratio, the long-term strength development is small compared to ordinary cement, and in particular, the strength decreases at ages 91 and 180 compared to ages 28 days. From the viewpoint of durability, it is known that fly ash, blast furnace slag powder, or the like is blended with eco-cement to improve the strength (see Non-Patent Document 1). The strength of eco-cement is improved by blending fly ash and blast furnace slag with 30% or more of eco-cement, but the amount of fly ash is large and the particle size is fine. Otherwise, it is difficult to obtain the effect, and those having a small particle size are expensive and difficult to use for general purposes. In addition, the extreme initial strength tends to decrease. For this reason, eco-cement has a high water-cement ratio, requires strength development from the very beginning, and is not often used for construction that requires durability. However, from the viewpoint of effective use of waste, effective use is expected by expanding the use.

JP-A-61-92263 JP 11-335152 A

Concrete Engineering Annual Papers, Vol. 30, no. 1, 2008, Long-term strength improvement of eco-cement by mixing ordinary Portland cement and finely ground fly ash

The present invention relates to a spraying material and a spraying material using the spraying material that can prevent the initial high setting property and strength development and the long-term strength deterioration of the ecocement at a high water cement ratio in spraying construction using ecocement. Provide a method of attaching.

That is, the present invention provides (A) titanium sulfate, (B) mortar or concrete composed of (1) ecocement, fly ash, aggregate, and an additive composed of calcium aluminate and calcium sulfate. Spraying material containing any of the alkali-free liquid quenchers containing aluminum sulfate, fluorine, oxalic acid, (C) aluminum sulfate, magnesium, silica, (2) calcium aluminate and calcium sulfate as additives (1) spraying material having a mixing ratio of 1: 1 to 1: 5 by mass ratio, (3) spraying material of (1) or (2) in which calcium sulfate is anhydrous gypsum, (4) The mortar or concrete water-cement ratio of the spray material of any one of (1) to (3) is 50% by mass or more, and the material age is 91 days with respect to the strength of the material age of 28 days. Spray material that does not decrease in strength, and any spray material of any one of (5) (1) to (3) is kneaded in advance as mortar or concrete with ingredients other than the alkali-free liquid quenching agent, immediately before spraying A spraying method in which an alkali-free liquid quick-setting agent is added to and sprayed.

  According to the spraying material of the present invention and the spraying method using the same, it can be applied to places where high initial setting properties and strength development are required using ecocement, and is manufactured from waste. Effective use and recycling of the eco-cement can be promoted through expansion of the use of eco-cement.

The present invention improves the initial setting properties and strength development when using ecocement for mortar or concrete in spray construction using an alkali-free liquid quick setting agent.
Ecocement is made from sewage sludge dry powder in which quick lime is mixed with shellfish and sewage sludge, municipal waste incineration ash such as other general waste and industrial waste, and one or more of sewage sludge incineration ash as raw materials. Using raw materials prepared by mixing ingredients such as limestone, clay, silica stone, aluminum ash, bauxite lees, iron, etc., which are cement raw materials, and mixing these materials with clinker obtained by firing these raw materials at 1200 to 1500 ° C. Or pulverizing only the clinker and mixing with gypsum as necessary.

Ecocement is a mineral component derived from aluminum and chlorine contained in raw materials, for example, 11CaO · 7Al ₂ O ₃ · CaCl ₂ (abbreviated as C11A7CaCl ₂ ), 3CaO · Al ₂ O ₃ (abbreviated as C ₃ A). Etc. are included. In addition, (abbreviated as _{C 2} S) 2CaO · _{SiO 2} contained in the normal cement includes one or more 3CaO · _SiO 2 _{(C 3} S for short).

In the present invention, an ecocement containing 10 to 40% by mass of one or more of C ₁₁ A ₇ CaCl ₂ to C ₃ A is used as a cement-based material. When the content of these aluminum compounds is less than 10% by mass, the reactivity with the liquid accelerator component is low, and sufficient rapid setting 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 mass, the amount of incinerated ash used is reduced, which is not preferable from the viewpoint of promoting effective utilization and recycling of waste. When the content of the aluminum compound exceeds 40% by mass, the hydration progresses remarkably, and the mortar and concrete may expand excessively, which is not preferable because long-term strength is inhibited.

Eco cement, aluminum compounds than normal Portland cement containing a large amount, the rapid-type to C ₁₁ A ₇ CaCl ₂ the components of the composition taken positively chlorine component of the raw material, in the firing step It is known that the normal type is composed of C ₃ A having a composition obtained by removing most of the chlorine component.
Any of the present invention can be used according to its use conditions.

The calcium aluminate contained in the additive of the present invention is obtained by mixing a raw material containing calcia, a raw material containing alumina, etc., and performing a heat treatment such as baking in a kiln or melting in an electric furnace. CaO and Al ₂ O ₃ are the main components and is a general term for substances having hydration activity. Some of CaO and Al ₂ O ₃ are alkali metal oxides, alkaline earth metal oxides, silicon oxides, oxides. Compounds substituted with titanium, iron oxide, alkali metal halides, alkaline earth metal halides, alkali metal sulfates, alkaline earth metal sulfates, or the like, or those containing CaO and Al ₂ O ₃ as main components In addition, these are substances in which a small amount is dissolved. Examples of the mineral form include CaO · Al ₂ O ₃ (CA), 12CaO · 7Al ₂ O ₃ (C ₁₂ A ₇ ), 3CaO · Al ₂ O ₃ (C ₃ A), and the like.
The particle size of the calcium aluminate used in the present invention is preferably a brane specific surface area (hereinafter referred to as a brane value) of 3,000 cm ² / g or more in terms of rapid setting and initial strength development, and 5,000 cm ² / g. The above is more preferable. If it is less than 3,000 cm < ² > / g, the quick setting property and initial strength expression property of the spray material which mixed the quick setting agent, mortar, and concrete may fall.
The CaO / Al ₂ O ₃ molar ratio of the calcium aluminate used in the present invention is in the range of 1.0 to 3.0, preferably 1.5 to 2.5. If it is within the range of the molar ratio, it can be used regardless of the form of crystalline or amorphous.

Calcium sulfate (gypsum) contained in the additive of the present invention includes anhydrides, hemihydrates, and dihydrates, with anhydrides being preferred. Both by-products and natural products can be used and used in powder form. The grain size is preferably a brain value of 4000 cm ² / g or more.

In the additive of the present invention, the mixing ratio of calcium aluminate and calcium sulfate is preferably 1: 1 to 1: 5 by mass ratio, and more preferably 1: 3 to 1: 5 by mass ratio. When the mass ratio of calcium aluminate exceeds 1, long-term strength development is reduced. Moreover, when the mass ratio of calcium sulfate exceeds 5, the initial strength development is reduced.
It is preferable to adjust the mortar or concrete unit amount of the additive within a range of 5 to 100 kg / m ³ .

  The fly ash used in the present invention is a fly ash described in JIS A6201, and classified, unclassified raw powder, its type, chemical composition, and physical properties are particularly limited. is not.

The fly ash used in the present invention must be used from the viewpoint of chloride in the eco-cement, and the unit amount of fly ash in the mortar or concrete is preferably adjusted within a range of 20 to 200 kg / m ^3. . Moreover, it is also possible to mix | blend as an aggregate and it is also possible to mix | blend as a part of cement.

The aggregate used in the present invention preferably has a low water absorption rate and a high aggregate strength. The maximum size of the aggregate is not particularly limited as long as it can be sprayed. As fine aggregate, river sand, mountain sand, sea sand, lime sand, and quartz sand can be used, and as coarse aggregate, river gravel, mountain gravel, lime gravel, etc. can be used, crushed sand, Crushed stone can also be used.
The unit amount of aggregate in mortar or concrete is preferably adjusted within a range of 1000 to 2000 kg / m ³ .

The water content of the mortar or concrete of the spray material of the present invention is 50% by mass or more. Even when the water-cement ratio is 50% by mass or more, the strength of the material at 91 days is not lowered with respect to the strength at the material age of 28 days. When the water-cement ratio is less than 50% by mass, the strength after 91 days of age does not decrease with respect to the strength of 28 days of age. Without being able to respond.

The present invention uses an alkali-free liquid quencher. Alkali-free generally does not contain alkali ions such as Na +, K +, or 1% by mass or less, and is not alkaline (pH 1-7).
The alkali-free liquid accelerating agent of the present invention includes, as a main component, titanium sulfate or aluminum sulfate substantially free of alkali, an alkali-free liquid accelerating agent containing titanium sulfate (A), aluminum sulfate blended with fluorine, or sulfuric acid. Alkali-free liquid quick-setting agent (B) in which the solid content concentration of aluminum sulfate is increased by adding oxalic acid as a complexing agent to increase the solid content concentration of aluminum, and liquid quick-setting agent containing magnesium sulfate and silica in aluminum sulfate ( C). Among them, the alkali-free liquid quick-setting agent (A) containing titanium sulfate showed very good physical properties in combination with ecocement.

  The alkali-free liquid quick setting agent of the present invention is preferably blended so as to be 8 parts by weight or more in a total of 100 parts by weight of the ecocement and the alkali-free liquid quick setting agent. Moreover, it is also possible to add two or more of the above three alkali-free liquid accelerating agents.

As the spraying method using the spraying material of the present invention, various spraying methods corresponding to the required physical properties, economy, workability and the like are possible, but the wet spraying method is preferable.
In the present invention, the spraying material is a spraying method in which components other than the alkali-free liquid quick-setting agent are kneaded in advance as mortar or concrete, and the alkali-free liquid quick-setting agent is added and sprayed immediately before spraying. preferable.

"Experiment 1"
800 g (511 kg / m ³ ) of the cement shown in Table 1, 10 parts by mass (52 kg / m ³ ) of additive α consisting of calcium aluminate and calcium sulfate with respect to 100 parts by mass of cement, 100 g of fly ash (60 kg / m ³⁾ fine aggregate 2000g (1277kg ^{/ m} 3), a total of 100 mass of water 480g (307kg / ^{m 3)} alkali-free liquid quick-setting admixture for cement and alkali-free liquid quick-setting admixture shown in Table 1 in the wet mortar consisting of In the part, 8 parts by mass were added to prepare a mortar, and the setting time and compressive strength after adding the alkali-free liquid quick-setting agent were measured. The results are also shown in Table 1.

<Materials used>
Cement (1): Ordinary Portland cement, commercially available, Blaine specific surface area 3000 cm ² / g, density 3.15 g / cm ³
Cement (2): Ordinary eco-cement, commercial product, Blaine specific surface area 3100 cm ² / g, density 3.18 g / cm ³
Cement (3): Quick-hardening eco-cement, commercially available product, Blaine specific surface area 3800 cm ² / g, density 3.15 g / cm ³
Additive α: a mixture ratio of calcium aluminate and calcium sulfate having a mass ratio of 1: 3, density of 2.78 g / cm ³
Fly ash: Class II product of JIS A6201, density 2.40 g / cm ³ , brain 4500 cm ² / g
Calcium aluminate: CaO / Al ₂ O ₃ molar ratio 2.3, brane 8000 cm ² / g, amorphous calcium sulfate: anhydrous gypsum, brane 5000 cm ² / g, density 2.90 g / cm ³
Fine aggregate: Niigata Himekawa water system sand, 5mm vulgar, density 2.62g / cm ³
Water: Drinking water Alkali free liquid quick setting agent (1): Liquid mainly composed of titanium sulfate, liquid, pH 1.7
Alkali-free liquid quick-setting agent (2): Liquid mainly composed of aluminum sulfate, pH 2.5
Alkali-free liquid quick-setting agent (3): Liquid mainly composed of aluminum sulfate, fluorine and oxalic acid, pH 2.8
Alkali-free liquid quick-setting agent (4): Liquid mainly composed of aluminum sulfate, magnesium and silica, pH 2.9

<Measurement method>
Setting time: Measured according to the Japan Society of Civil Engineers standard "Quality standard for shotcrete for sprayed concrete (JSCE D-102)" Compressive strength: Measured according to JIS R 5201

  From the results shown in Table 1, in the case of ordinary cement, even if the type of the alkali-free liquid quick setting agent is changed, no significant improvement in the setting of the setting and compressive strength is observed. When the type of cement is ecocement, improvement of setting and compressive strength is confirmed. Furthermore, it was confirmed that the setting and compressive strength were further improved when fast-curing ecocement was used. Further, in the case of ecocement, a decrease in strength was confirmed as 91 days and 180 days elapsed from the age of 28 days. However, when the alkali-free liquid quenching agent of the present invention was used, good results were obtained without a decrease in strength.

"Experiment 2"
800 g (511 kg / m ³ ) of cement (2) or cement (3) shown in Table 2, 10 parts by mass (51 kg / m ³ ) of additive of the type shown in Table 2 with respect to 100 parts by mass of cement, fly ash 100g (60kg ^{/ m} 3), fine aggregate 2000g (1277kg ^{/ m} 3), water 400g (307kg / ^{m 3)} cement wet mortar alkali-free liquid quick-setting admixture shown in Table 2 made of an alkali-free liquid quick-setting 8 parts by mass of a total of 100 parts by mass of the agent was added to prepare a quick setting mortar, and the setting time and compressive strength after adding the alkali-free liquid quick setting agent were measured. The results are also shown in Table 2.

<Materials used>
Additive β: a mixture ratio of calcium aluminate and calcium sulfate having a mass ratio of 1: 5, density of 2.85 g / cm ³
Additive γ: Mixing ratio of calcium aluminate and calcium sulfate being a mass ratio of 1: 1, density 2.70 g / cm ³

<Measurement method>
Setting time: Measured according to Japan Society of Civil Engineers standard "Quality standard for sprayed concrete quality (JSCE D-102)" Compressive strength: Measured according to JIS R5201

  From the results in Table 2, when the mixing ratio of calcium aluminate and calcium sulfate is a mass ratio of 1: 1, the additive tends to decrease in coagulation and compressive strength. Moreover, according to long-term material age, the thing with a high mixing ratio of a calcium aluminate loses elongation of strength. Since there is much quantity of calcium aluminate, even if it mixes with an alkali free liquid quick setting agent, it is thought that what reacts with an alkali free liquid quick setting agent is insufficient. When the mixing ratio of calcium aluminate and calcium sulfate was a mass ratio of 1: 3 to 1: 5, good coagulation and compressive strength were exhibited, and the strength increased according to the material age. Moreover, the results using titanium sulfate as the alkali-free liquid accelerating agent were good in all respects compared to other alkali-free liquid accelerating agents.

"Experiment 3"
Prepare concrete so that the concrete slump is 18 cm using the composition (kg / m ³ ) shown in Table 3 consisting of eco-cement, water, fine aggregate, coarse aggregate, fly ash, additive α and water reducing agent. Then, pumping was performed by a concrete pumping machine “MKW-25SMT” under the conditions of a spraying pressure of 6 MPa and a spraying speed of 10 m ³ / h. From the holes provided in several places around one tube, the alkali-free liquid quick-setting agent of the type shown in Table 4 is pumped to 8 parts by weight in a total of 100 parts by weight of cement and alkali-free liquid quick-setting agent, It was mixed with concrete pumped from the other side and used as spray material. The compressive strength was measured for this spray material. The results are also shown in Table 4.

<Materials used>
Coarse aggregate: Himekawa Sakegawa gravel, Itoigawa City, Niigata Prefecture, surface dry state, density 2.67 g / cm ³ , maximum dimension 15 mm
Water reducing agent: Polycarboxylic acid, commercially available

<Measurement method>
Concrete compressive strength: 3 hours old, 1 day compressive strength, the pin placed on the pull-out formwork of width 25cm x length 25cm is covered with spray material from the surface of the pull-out formwork, and the pin from the back side of the formwork The pullout strength at that time was determined, and the compressive strength was calculated from the formula of (compressive strength) = (pullout strength) × 4 / (test specimen contact area). The compressive strength after the age of 28 days was measured by spraying a spraying material on a mold having a width of 50 cm, a length of 50 cm, and a thickness of 20 cm, and a sample having a diameter of 5 cm and a length of 10 cm with a 20-ton pressure machine. The compressive strength was determined.

  From the results of Table 4, when the present invention is applied to shotcrete using eco-cement, the compressive strength development is good, and the strength enhancement effect is obtained with long-term aging, similar to ordinary cement. It was shown that it can be done.

"Experimental example 4"
Similar to Experimental Example 3, the concrete slump becomes 18 cm using the composition (kg / m ³ ) shown in Table 5 consisting of cement, water, fine aggregate, coarse aggregate, fly ash, additive α, and water reducing agent. Concrete was prepared as described above, and then pumped by a concrete pumping machine “MKW-25SMT” under a spraying pressure of 6 MPa and a spraying speed of 10 m ³ / h. From the holes provided in several places around one tube, the alkali-free liquid quick-setting agent of the type shown in Table 6 is pumped to 8 parts by mass in a total of 100 parts by weight of cement and alkali-free liquid quick-set agent, It was mixed with concrete pumped from the other side and used as spray material. The compressive strength was measured for this spray material. The results are also shown in Table 6.

<Measurement method>
Concrete compressive strength: 3 hours old, 1 day compressive strength, the pin placed on the pull-out formwork of width 25cm x length 25cm is covered with spray material from the surface of the pull-out formwork, and the pin from the back side of the formwork The pullout strength at that time was determined, and the compressive strength was calculated from the formula of (compressive strength) = (pullout strength) × 4 / (test specimen contact area). The compressive strength after the age of 28 days was measured by spraying a spraying material on a mold having a width of 50 cm, a length of 50 cm, and a thickness of 20 cm, and a sample having a diameter of 5 cm and a length of 10 cm with a 20-ton pressure machine. The compressive strength was determined.

  From the results shown in Table 6, it can be seen that the long-term strength of the present invention product does not decrease even when ecocement is used in a concrete blend having a water cement ratio of 50 mass% or 60 mass%.

  According to the spraying material of the present invention and the spraying method using the same, it can be applied to places where high initial setting properties and strength development are required using ecocement, and is manufactured from waste. It can be used in a wide range of fields such as civil engineering and construction because it can promote effective use and recycling through expansion of the use of ecocement.

Claims (5)

And Ecocement, and fly ash, and aggregate, Oite mortar or concrete consists of an additive material consisting of calcium aluminate and calcium sulphate, the unit amount of ecocement 400~511kg / m ^3, the fly ash unit weight of 20 to 200 kg / ^{m 3,} the unit amount 1000~2000kg / ^{m 3} of aggregate, additional material is 5 to 100 kg / ^{m 3,} the alkali-free liquid quick-setting admixture comprising (a) sulfate titanium down A spraying material that is blended so as to be 8 parts by mass or more in a total of 100 parts by mass of ecocement and alkali-free liquid quick setting agent . The spraying material according to claim 1, wherein a mixing ratio of calcium aluminate and calcium sulfate as an additive is 1: 1 to 1: 5. The spraying material according to claim 1 or 2, wherein the calcium sulfate is anhydrous gypsum. The water-cement ratio of mortar or concrete is 50% or more, and the strength of a material age of 91 days does not decrease with respect to the strength of a material age of 28 days. Spray material. The spraying material according to any one of claims 1 to 3, wherein components other than the alkali-free liquid accelerator are kneaded in advance as mortar or concrete, and the alkali-free liquid accelerator is added immediately before spraying. A spraying method characterized by spraying.