JP2726474B2 - Lining material and method for manufacturing lining pipe using the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a lining material and a method for manufacturing a lining pipe, and more particularly, to a lining material supplied to water and sewage systems and lining a pipe inner surface such as a steel pipe or a cast iron stake. And a method for manufacturing a lining tube.

[Conventional technology and its problems]

2. Description of the Related Art Conventionally, a lining is provided on an inner surface of a steel pipe or a cast iron pipe used for water supply and sewerage in order to prevent rust, improve durability, and stabilize water quality of tap water and the like.

Portland cement mortar is used as the lining material. However, when used for water supply pipes, the alkali in the mortar elutes during the initial passage of water, and there is a problem that the pH of the water significantly increases to 10 or more.

In order to suppress the rise in pH and prevent the mortar layer from being destroyed under acidic conditions, a seal coat material is usually applied to the surface of the lining layer in Portland cement mortar lining.

However, in actual use by embedding, the seal coat material is peeled off by acidic water such as groundwater or sewage containing a lot of free carbonic acid, and the surface of the lining layer is exposed and the pH rises. There was a problem that the material was clogged in the pipes, water pumps, etc., released into the tap water, and the tap water had a bad smell. Another problem is that Ca ²⁺ elutes from the peeled surface of the seal coat material, the lining layer is broken, and the durability is reduced. As a method for suppressing an increase in the pH of water in the early stage of passing water without applying a seal coat material, a lining method for the inner surface of a pipe using cement and sand with a small amount of R ₂ O has been proposed (JP-A-63-296874). . However, using this lining method,
Although the rise can be suppressed, Al in alumina cement mortar
Is eluted, and the amount of soluble Al increases remarkably during initial water passage,
There was a problem that drinking water became cloudy. In addition, the centrifugal molding has a problem in that a large amount of cement segregates on the inner surface and the durability against acidic water is not sufficient.

In particular, soluble Al in drinking water is reported to be unhealthy when taken in large quantities (Metal, 1985, 55 (7), P63
~ 65, Toshihiko Sato and Asahi Shimbun 1989, January 17, etc.)

Conventional lining pipe, is used Portland cement, soluble for hydraulic calcium aluminate 3CaO · Al ₂ O ₃ of which causes the soluble Al is not contained only trace amounts A
The l level was at a very low level of 0.2 ppm or less without a seal coat. However, when alumina cement is used as disclosed in JP-A-63-296874, CaO.Al ₂ O ₃ , Ca
To include O · 2Al ₂ O ₃ and hydraulic calcium aluminate such as 12CaO · 7Al ₂ O ₃ as the main mineral, there has been a problem that the amount of soluble Al is increased remarkably.

In addition, alumina cement generates more heat at the beginning of hydration than Portland cement.Therefore, the moisture on the lining layer surface evaporates when the mortar hardens, and the unhardened part due to lack of hydration water is generated and the surface is powdered. Atsuta. For this reason, in order to make the surface of the lining layer uniform, it is necessary to polish it thickly, and there is a problem that it takes a lot of time and labor to polish and dispose of the polishing powder.

The present inventors have conducted intensive studies to solve the above problems, and as a result, in order to prevent an increase in the pH of water in the initial stage of water flow, an increase in the amount of soluble Al, and uncured surface of the cured mortar, a lining material having a specific composition is used. The present inventors have found that it is effective to use them, and have completed the present invention.

[Means for solving the problem]

That is, the present invention provides a binder comprising 85 to 99 parts by weight of alumina cement and 15 to 1 part by weight of silica fume, sand,
And a lining material containing water as a main component, and a combination of an inorganic expanding material and a water reducing agent, and a method for manufacturing a lining tube using the same.

 Hereinafter, the present invention will be described in detail.

Alumina cement according to the present invention (hereinafter referred to as AC)
Is a clinker synthesized from a source of alumina such as bauxite, Bayer alumina and alumina residual ash, and a source of calcia such as quicklime, limestone and slaked lime by a melting method and / or a firing method, such as a ball mill, a roller mill and an angmill. It is crushed by a crusher.

The mineral composition is CA, C, where CaO is C and Al ₂ O ₃ is A.
_{A 2, C 3 A, C} 12 A 7, C 5 A 3 and C ₃ shall apply essentially provided by a hydraulic calcium aluminate represented as A _5, etc., alumina gel upon hydration hardening (Al (OH) ₃ ) Less generation of C /
A (molar ratio) ≦ 1 AC is preferable, and a hydraulic calcium aluminum of _{30 to} 40% by weight of CaO and 40 to 60% by weight of Al ₂ O ₃ having good pot life, curability and strength development. Nates are particularly preferred.

The silica fume (hereinafter referred to as SF) according to the present invention is generally a volatilizable silica produced as a by-product when producing silicon, ferrosilicon, fused silica, etc., such as micro silica, silica flour, and silica dust. It is also called.

In particular, in order to achieve the object of the present invention, the pH of SF is important, and pH ≦ 8 is preferred, and those having a pH of 6 to 8 near neutrality are more preferred.

The pH referred to in the present invention means that 2.0 g of SF is added to ion-exchanged water at room temperature.
It is a value when the pH of the slurry obtained in 200 ml and stirred with a stirrer reaches equilibrium.

If the pH of SF exceeds 8, when used as a lining material, the pH during initial water passage increases and the amount of soluble Al increases, which is not preferable. On the other hand, when the pH is less than 6, the reaction with AC is lacking, the strength is deteriorated, and the durability is hardly obtained. Furthermore, SF is a BE with good reactivity with AC.
Those having a T specific surface area of 10 to 25 m ² / g are preferable, and those having a SiO ₂ content of 80% by weight or more are preferable because of good long-term strength.

The mixing ratio of AC and SF according to the present invention is 85 to 99% by weight of AC and 15 to 1 part by weight of SF. If the amount is less than 1 part by weight of SF, the effect of reducing the amount of soluble Al is lacking, and if it exceeds 15 parts by weight, the strength development is poor, and the tightness of the lining layer during centrifugal molding tends to be poor.

As the inorganic expanding material (hereinafter referred to as expanding material) according to the present invention, an etarigite-producing material composed of calcium sulfoaluminate or gypsum, or a lime-based material composed of calcium fluoride or calcium oxide can be used.

In particular, an ettringite-producing system is preferable because a pot life can be obtained.

It is preferable that the blending ratio of the binder and the expander formed by blending AC and SF is 85 to 98 parts by weight of the binder and 15 to 2 parts by weight of the expander, and particularly, 90 to 96 parts by weight of the binder and the expander. 10 to 4 parts by weight are more preferred.

If the amount of the intumescent material exceeds 15 parts by weight, the lining layer will tend to expand and break when used for a long time, and if it is less than 2 parts by weight, the effect of the intumescent material will be lacking and shrinkage cracks will occur in the lining layer. There is a tendency and it is not preferable.

The expansive material and particle size are preferably about the same as AC,
2,500 cm ² / g or more is preferable in the Brain method, and 4,000 to 6,000
cm ² / g is more preferred. If it is extremely coarse or finer than AC, it is not preferable because it segregates by centrifugal molding and causes cracks.

The water reducing agent according to the present invention is a lignin sulfonate type,
Naphthalene sulfonate type, naphthalene sulfonate formalin condensate type, melamine sulfonate formalin condensate type, polycarboxylate type, phosphoric acid type, boric acid type and oxycarboxylate type, etc. Phosphoric acid type or boric acid type, which forms a sparingly soluble salt with Al and has both a water reducing effect and a soluble Al suppressing effect, is particularly preferred, specifically, hexametaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid and boric acid or Na salt and K salt thereof.

Each water reducing agent can be used alone or in combination. The amount of the water reducing agent is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the total amount of the binder and the swelling agent (hereinafter referred to as powder). 0.1 to 2 parts by weight from the surface is particularly preferred.

The sand according to the present invention is preferably river sand or mountain sand in which salt damage or efflorescence is less likely to occur, and sea sand is not preferable because it contains a large amount of NaCl.

The amount of sand used is 100 parts by weight of binder or powder,
100-300 parts by weight of sand is usually used, and is used depending on the pipe diameter. For example, a ratio physician sand 100 to 270 parts by weight per 100 parts by weight of the binder or powder in tube 100 to 700 ^phi mm.

In the present invention, the above materials are kneaded with water in a mixer such as a pan mixer or a paddle mixer, and the kneading temperature of the mortar is preferably 25 ° C. or lower, and particularly preferably around 20 ° C.

If the temperature exceeds 25 ° C., false coagulation tends to occur, and it is difficult to obtain a pot life, which is not preferable. On the other hand, a high kneading temperature is not preferable because the amount of Al (OH) ₃ produced by the transfer reaction of the AC hydrate increases and the amount of soluble Al increases. If the kneading temperature is as low as, for example, 5 ° C. or less, curing delay occurs and the strength is poor, so that it is not preferable to be too low.

The mortar flow value is preferably 200 mm or more as a 15-step tap flow value using a flow table, particularly 240 to 280 m
m is preferred. If the flow value is less than 200 mm, during centrifugal molding,
It is difficult to form a uniform lining layer on the inner surface of the pipe, 280 mm
If the ratio exceeds the above range, the lining layer will not be tightly tightened by centrifugal molding, and the paste layer will be separated, and cracks and peeling will tend to occur, which is not preferred.

Centrifugal molding is usually performed at 20G or more, but in the present invention,
In particular, 50 to 70 G is preferable because the lining layer is tight. Five
If it is less than 0G, the lining layer after centrifugal molding is poorly tightened,
The lifting of the latency is insufficient, and if it exceeds 70 G, the paste layer tends to separate and cracks are likely to occur, which is not preferable.

The centrifugal molding time at the maximum G is preferably 3 minutes or more, which is preferable because the lining layer becomes uniform and the tightening is good. In particular, a centrifugal molding time of 5 minutes or more is preferable because the water drainage from the lining layer is stable.

Tubes lined by centrifugal molding have a relative humidity of 60% R.
It is preferable to perform primary curing under humidification conditions of H. or higher, and more preferably 80% RH or higher. Curing temperature is 25 ℃
The following is preferable, and it is more preferable to perform low-temperature humidification curing at around 20 ° C.

The curing time is preferably at least 4 hours immediately after the completion of the lining, and more preferably until the heat of hydration of the cement is completed.

Humidification and curing under conditions other than the above conditions are not preferable because uncured portions are generated on the surface of the lining layer and powdered, and the amount of soluble Al does not decrease.

After the primary curing is completed, the surface of the lining tube is uniformly polished by an ordinary method, then secondary cured by air drying at room temperature for 2 days or more, and used for burying. The polishing thickness depends on the pipe diameter, but is usually about 0.5 to 3 mm from the surface.

The secondary curing period is preferably performed for 4 days or more when the initial water flow and the amount of soluble Al are sufficiently reduced, and particularly preferably 6 days or more.

As the pipe to be carried out by the method of the present invention, a cast iron pipe is usually used, but it is possible to use a pipe having a lining layer formed in advance by a conventional method, and to use a pipe having two or more lining layers. is there.

Further, blast furnace water frame slag powder, limestone powder, fly ash and the like may be added and mixed to improve durability of the lining pipe such as acid resistance and long-term stability.

When using these, the total amount with binder or powder
70 parts by weight or less is preferable for 100 parts by weight. If the amount exceeds 70 parts by weight, the strength of the lining layer decreases, and the durability decreases, which is not preferable.

Further, to obtain a low pH, addition of aluminum sulfate is also effective.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 AC and SF were blended as shown in Table 1, and mixed with a small omni mixer (manufactured by Chiyoda Giken Kogyo) for 55 minutes to produce a binder.

After 100 parts by weight of this binder and 200 parts by weight of river sand are kneaded with a pan-type mixer for 3 minutes, tap water is added to a flow value of 260 ± 20 mm, and the mixture is kneaded for 5 minutes.
A mortar at 20 ± 2 ° C. was prepared.

The mortar by centrifugal molding ^machine, 100 φ mm × 500 ^l mm
A lining layer having a thickness of 5 mm was formed on the inner surface of the cast iron tube under the conditions of 50 G for 5 minutes.

After completion of lining, put in a humidifier at 20 ° C and 100% RH, perform primary curing for 12 hours, then grind the surface with a lathe for 1 mm, and further secondary cure under normal temperature air-dry condition for 6 days. A lining tube was obtained. The physical properties are also shown in Table 1.

For comparison, 100 parts by weight of Denka Alumina Cement No. 2 manufactured by Denki Kagaku Kogyo Co., Ltd. and 200
After kneading the parts by weight with a bread mixer for 3 minutes, 260 ± 20m
Tap water was added so as to obtain a flow value of m, and kneaded for 5 minutes to prepare a mortar having a kneading temperature of 20 ± 2 ° C.

To form a lining layer having a thickness of 5mm at the conditions of 40G-2 min cast iron pipe surface of ¹⁰⁰ φ mm × 500 ^l mm by the mortar centrifugal molding machine. After completion of the lining, primary curing was performed for 24 hours under the condition of air drying at room temperature, and then the surface of the lining layer was polished with sandpaper while sprinkling tap water on the surface of the lining layer to polish the 0.6 mm surface.

After that, it is further cured for 6 days under normal temperature and air drying condition,
A lining tube was made.

<Measurement method> (1) Flow value; Spread diameter of mortar after tapping 15 times with a flow table (2) Strength; Compressive strength with 4 × 4 × 16 cm test piece (3) pH; Inside lining pipe after secondary curing After washing the surface with ion-exchanged water, add 3,000 ml of ion-exchanged water,
It was immersed at 0 ° C. and adjusted to the pH of the immersion water.

(4) Soluble Al content; value obtained by analyzing immersion water after pH measurement by ICP.

<Materials used> AC-a: Trade name “DENKA Alumina Cement No. 1”, CaO 36.5 wt%, Al ₂ O ₃ 53.5 wt% manufactured by Denki Kagaku b: b “DENKA Alumina Cement No. 2” Denki Kagaku Kogyo 33.0% by weight of CaO, 48.5% by weight of Al ₂ O ₃ AC-c: Trade name “DENKA HIGH Alumina Cement” CaO 25.5
Weight%, Al ₂ O ₃ 73.5 weight% SF-d: silica fume, pH 8.3, BET22m ² / g, SiO ₂ 83.1%,
Erukemu manufactured by e: ^{Shirikahiyumu, pH7.8, BET24m 2 / g,} SiO 2 93.1%,
Erukemu Co., Ltd. f: ^{Shirikahiyumu, pH6.8, BET21m 2 / g,} SiO 2 97.2%,
Elchem sand: Tamana river sand, Kumamoto Prefecture Fly ash: pH 10.4, BET 0.7 m ² / g, SiO ₂ 61.4%, Kanden Kako silica: pH 6.1, BET 0.1 m ² / g, SiO ₂ 99.0% , Silica powder Example 2 A composition was manufactured by blending a binder and an expanding material as shown in Table 2 and mixing them for 55 minutes using a small omni mixer.

100 parts by weight of this composition and 200 parts by weight of river sand are kneaded with a pan mixer for 3 minutes, then a predetermined amount of a water reducing agent is added, tap water is added so that the flow value becomes 260 ± 20 mm, and mixed for 5 minutes.
A mortar having a kneading temperature of 20 ± 2 ° C. was prepared.

Using this mortar, a lining tube was obtained in the same manner as in Example 1. The physical properties are also shown in Table-2.

The measurement of physical properties and materials were the same as in Example 1, and the others were as follows.

<Measurement Method> (1) Tightening of the lining layer;

(2) Surface cracks: The presence or absence of cracks on the surface of the lining tube that was secondarily cured for 50 days under normal temperature air-dry conditions was visually determined.

<Materials> Swelling agent g: Trade name "DENKA CSA ^# 20", manufactured by Denki Kagaku Kogyo h: trade name "for Expan products", manufactured by Onoda Cement j: type II anhydrous gypsum, manufactured by Central Glass Water reducer k: trade name "Mighty 150" made by Kao Soap l: Trade name "Vinsol 80" made by Yamamune Chemical m: Trade name "Pozoris No.5L" Made by Pozoris n: Na hexametaphosphate, Kanto Chemical reagent first class p: Hexametaphosphate K, Kanto Chemical Reagent grade q: Na tripolyphosphate, Kanto Chemical grade 1 Water reducing agent r: Boric acid, Kanto Chemical grade 1 s: Borax, Kanto Chemical grade 1 Example 3 After 100 parts by weight of the composition of Experiment No. 2-4 and 200 parts by weight of river sand were kneaded with a pan-type mixer for 3 minutes, tap water was added to a flow value of 260 ± 20 mm, and mixed for 5 minutes. Kneading temperature
A mortar at 20 ± 2 ° C. was prepared.

The mortar was formed lining layer having a thickness of 5mm under the conditions shown in Table 3 in the cast iron pipe surface of ¹⁰⁰ φ mm × 500 ^l mm by centrifugal molding machine.

The processing after completion of the lining was performed in accordance with Example 1, the measurement of physical properties and materials were performed in accordance with Examples 1 and 2, and the others were performed as follows. The physical properties are also shown in Table-3.

<Measurement Method> (1) Drainage of water from the lining layer;

(2) Finish of lining layer; To form a lining layer having a thickness of 5mm under the conditions of Example 4 by mortar centrifugal molding machine manufactured by the method of Example ³ 100 φ mm × 500 ^l mm cast iron pipe surface 50G-5 minutes.

After completion of the lining, primary curing was performed under the conditions shown in Table-4, and then the surface was polished by a lathe with a thickness of 1 mm. Further, secondary curing was performed under predetermined conditions to obtain a lining tube.

Table 4 shows the curing conditions and physical properties of the lining tube.
The measurement of physical properties and the material were in accordance with Example 2.

[Effects of the Invention] As is clear from the above, the pipe manufactured according to the present invention can keep the initial water flow pH low without applying a seal coat, and has a higher soluble Al content than the conventional lining pipe using AC.
The amount can be significantly reduced.

Further, powdering of the lining surface generated during the primary curing can be prevented, and a lining tube having a good surface finish can be obtained.

Claims (4)

(57) [Claims] 1. A lining material containing 85 to 99 parts by weight of alumina cement and 15 to 1 parts by weight of silica fume, sand and water as main components. 2. A method for manufacturing a lining pipe, comprising: lining the lining material according to claim 1 on an inner surface of the pipe by a centrifugal force forming method, and curing the lining layer by heating and curing. 3. 85 to 98 parts by weight of the binder according to claim 1,
A lining material mainly composed of 15 to 2 parts by weight of an inorganic expander and 0.1 to 5 parts by weight of a water reducing agent with respect to 100 parts by weight of a total of a binder and an inorganic expander. 4. A method for manufacturing a lining pipe, comprising: lining the lining material according to claim 3 on the inner surface of the pipe by a centrifugal molding method; and curing the lining layer by heating and curing.