JP2726475B2 - Lining material and method of manufacturing lining tube using it - Google Patents

Description

The present invention relates to a lining material and a method for manufacturing a lining pipe, and more particularly, to a lining material for lining an inner surface of a pipe such as a steel pipe or a cast iron pipe supplied for water supply. The present invention relates to 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.

As this lining material, Portland cement mortar is usually used, but when used for water supply pipes, the alkali content in the mortar elutes during the initial passage of water, and the pH of the water is reduced.
However, there was a problem that the number increased remarkably to 10 or more.

In Portland cement mortar lining, a seal coat material is usually applied to the surface of the lining layer in order to prevent the mortar layer from being broken under acidity, which suppresses the increase in pH.

However, in actual use by embedding, the seal coat material is decomposed and peeled off by acidic water such as groundwater or sewage containing a lot of free carbon dioxide, etc., and the lining layer surface is exposed and pH
There is a problem that the seal coat material rises, the peeled seal coat material is clogged in a water supply pump or the like, floats in a water supply water, and a bad smell is generated in the water supply water. 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. R ₂ O is used as a method to suppress the rise of water pH in the early stage of water flow without applying a seal coat material.
There has been proposed a lining method for the inner surface of a pipe using a cement and a sand having a small amount (JP-A-63-296874). However, by using this lining method, although the rise in pH can be suppressed, Al in the alumina cement mortar elutes,
There was a problem that the amount of soluble Al increased remarkably at the time of initial water passage, and drinking water became cloudy. In addition, due to the centrifugal molding, there was a problem that a large amount of cement was segregated on the inner surface and the durability against acid water was 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, Nikkan Kogyo Shimbun 1988, October 29, Asahi Shimbun 1989, January 17, etc.), and lining tubes with high soluble Al content are practical even if they have the effect of suppressing pH rise. It was not made.

The lining tube using conventional Portuguese cement mortar, since the soluble Al causative hydraulic calcium aluminate 3CaO · Al ₂ O ₃ of sulfonates of only contains trace amounts, is also soluble Al content without seal coat 0.2 Very low levels below ppm. However, when alumina cement is used as disclosed in JP-A-63-296874, CaO.Al ₂ O ₃ , Ca
Since it contains hydraulic calcium aluminate such as O.2Al ₂ O ₃ and 2CaO.7Al ₂ O ₃ as main minerals, there is a problem that the amount of soluble Al increases remarkably, so that it cannot be used practically.

In addition, alumina cement generates more heat at the beginning of hydration than Portland cement, so moisture on the lining layer surface evaporates when the mortar hardens, and unhardened parts are generated due to lack of water needed for hydration, and the surface becomes powdered. There was a problem to do. For this reason, to make the lining layer surface uniform,
There is a problem that it is necessary to polish thickly, and it takes a lot of time and labor to polish and dispose of polishing powder.

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

[Means for solving the problem]

That is, the present invention relates to a lining material mainly composed of a binder, sand and water comprising 30 to 95 parts by weight of alumina cement and 70 to 5 parts by weight of granulated blast furnace slag powder, and further comprises an inorganic expanding material and a water reducing agent. This is a method for producing a lining tube using these lining materials.

 Hereinafter, the present invention will be described in detail.

Alumina cement according to the present invention (hereinafter referred to as AC)
Is a method using a clinker synthesized from a source of alumina such as bauxite, Bayer alumina and alumina residue ash and a source of calcia such as quicklime, limestone and slaked lime by a melting method and / or a firing method. Crushed by a crusher.

The mineral composition is CA, CA, where CaO is C and Al ₂ O ₃ is A.
₂ , mainly composed of hydraulic calcium aluminate, such as C ₃ A, C ₁₂ A ₇ , C ₅ A _3, C ₃ A _5, etc., which is used for alumina gel (Al (OH) ₃ ) With low 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.

Granulated blast furnace slag powder (hereinafter referred to as slag powder) according to the present invention has a vitrification ratio of 80% or more and a basicity (CaO + MgO +
Al ₂ O ₃ ) / SiO ₂ ≧ 1.5 (weight ratio),
In particular, 1.8 or more is excellent in latent hydraulic property and is preferable. The vitrification ratio is a value calculated from the area of a diffraction line obtained by powder X-ray diffraction.

Vitrification ratio (%) = (1- diffraction line area / total area) × 100 Further, the particle size of the slag powder, a specific surface area by Blaine method, preferably at least ^{5,000cm 2 / g, 8,000cm 2 /} g or more More preferred. If it is less than 5,000 cm ² / g, the reactivity is poor, the strength development of the cured mortar is poor, and the amount of soluble Al increases, which is not preferable. In particular, 8,000 cm ² / g or more is preferable because the strength expression is good and the amount of soluble Al decreases.

The mixing ratio of AC and slag powder according to the present invention is AC 30 to 95
Parts by weight, 70 to 5 parts by weight of slag powder. If the amount of slag powder is less than 5 parts by weight, the effect of reducing the amount of soluble Al is poor.
Exceeding the weight part is not preferable because the curing is delayed and the strength is deteriorated.

In particular, 50 to 80 parts by weight of AC and 50 to 20 parts by weight of slag powder are preferable because of good strength development and the effect of reducing the amount of soluble Al.

As the inorganic expanding material (hereinafter referred to as an expanding material) according to the present invention, an ettringite molded system made of calcium sulfoaluminate, gypsum, or the like, or a lime based material made of calcium fluoride, calcium oxide, or the like can be used.

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

The compounding ratio of the binder and the intumescent material obtained by mixing the AC and the slag powder is preferably a ratio of 85 to 98 parts by weight of the binder and 15 to 2 parts by weight of the intumescent material, and particularly preferably 90 to 90 parts by weight of the binder.
96 parts by weight and 10 to 4 parts by weight of the expanding material are more preferable.

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 particle size of the expanding material is preferably about the same as AC,
Those having a Brain method of 4,000 to 6,000 cm ² / g are preferred. AC
If it is extremely coarse or fine, segregation due to centrifugal molding is caused, which is not preferable because it causes cracks. The Portland cement generally used is 2,500 to 3,500 cm ² / g, but in the present invention, the one in the above range is preferable.

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, the tube 100 to 700 ^phi mm, the proportion physician sand 100 to 270 parts by weight of a binder or powder 100 parts by weight.

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, if the kneading temperature is high, the production amount of Al (OH) ₃ accompanying the transfer reaction of the AC hydrate increases, and the amount of soluble Al increases, which is not preferable. 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. 50G
If it is less than 70 g, the mortar layer after centrifugal molding is not firmly tightened and the lift of the latence is insufficient. If it exceeds 70 G, the paste layer tends to separate and cracks tend 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 more, and more preferably 80% RH or more. The curing temperature is 25
C. or lower, and more preferably low-temperature humidification and curing at around 20.degree.

The curing time is preferably 4 hours or more 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 those described above are not preferable because uncured portions are generated on the surface of the lining layer and do not powder or reduce the amount of soluble Al.

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, and particularly preferably for 60 days or more, when the pH of the initial water flow and the amount of soluble Al are sufficiently reduced.

As the pipe carried out by the method of the present invention, a cast iron pipe is usually used, but a pipe having a lining layer previously formed by a conventional method, and a pipe having two or more lining layers can also be used. It is.

Further, in order to further improve the acid resistance and long-term stability of the lining tube, silica lime, limestone powder, fly ash, and a polymer for general polymer cement may be used in combination. As the polymer for polymer cement, natural rubber, chloroprene rubber (CR), styrene butadiene rubber (SBR), rubber latex such as vinyl alcohol, furfuryl alcohol and vinyl acetate, water-soluble polymer and resin emulsion can be used.

〔Example〕

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

Example 1 AC and slag powder were mixed as shown in Table 1, and mixed with a small omni mixer (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 to form a lining layer having a thickness of 5mm at the conditions of 50G-5 min cast iron pipe surface of ¹⁰⁰ φ mm × 500 ^l mm by centrifugal molding machine.

After completion of the lining, put in a humidifier at 20 ° C. and 100% RH and perform primary curing for 12 hours. Then, the surface was polished by 1 mm with a lathe, and further secondary cured under normal temperature and air drying conditions 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 a normal temperature and air drying condition, and then a 0.6 mm surface was polished with sandpaper while sprinkling tap water on the lining layer 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 according to a flow table.

(2) Strength; compressive strength by 4 × 4 × 16 cm test piece.

(3) pH; After the inner surface of the lining tube after the secondary curing was washed with ion-exchanged water, 3,000 ml of ion-exchanged water was added and immersed at 20 ° C. for 24 hours to obtain the pH of the immersion water.

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

(5) Surface powdering: The presence or absence of powdering of the lining surface after primary curing was visually determined.

<Materials used> AC-a: Trade name "DENKA Alumina Cement No. 1",
Manufactured by Denki Kagaku Kogyo Co., Ltd., CaO 36.5% by weight, Al ₂ O ₃ 53.5% by weight b: Trade name “DENKA Alumina Cement No. 2”,
Made by Denki Kagaku Kogyo Co., Ltd., 33.0% by weight of CaO, 48.5% by weight of Al ₂ O ₃ c: Trade name “Denka high alumina cement” Ca
O25.5 wt%, Al ₂ O ₃ 73.5 wt% slag powder -d: Sumitomo Metal Sales Co., blast furnace slag, basicity 2,06, plain 4,000cm ² / g CaO45.6 wt%, MgO6.
6% by weight, Al ₂ O ₃ 12.4% by weight, SiO ₂ 31.3% by weight −e: 5,000 plain 5,000cm ² / g −f: プ レ ー ン plain 8,000cm ² / g −g: プ レ ー ン plain 10,000cm ² / g Note, slag For the powder, samples having different specific surface areas were prepared by changing the pulverization time by a small batch type ball mill.

Sand: 2.5mm sieve under river sand from Tamana, Kumamoto Prefecture Fly ash: Blaine 3,500cm ² / g, SiO ₂ 61.4%, manufactured by Kanden Kako Co., Ltd. Silica: Blaine 3,000cm ² / g, SiO ₂ 99.0%, silica powder Example 2 A binder and a swelling agent were blended as shown in Table 2 and mixed for 55 minutes by a small omni mixer to produce a composition.

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) Surface Crack: 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 determined.

<Materials> Swelling agent h: Trade name "DENA CSA ^# 20"; manufactured by Denki Kagaku Kogyo j: trade name "for Xpan products"; made by Onoda Cement k: type II anhydrous gypsum; made by Central Glass Water reducer l: trade name "Mighty 150"; Kao Soap m: Trade name "Vinsol 80"; Yamamune Chemical n: Trade name "Pozoris No.5L"; Pozoris p: Na hexametaphosphate; Kanto Chemical Reagent 1st class q: 〃 K; 〃 r: Na tripolyphosphate; 〃 s: boric acid; 〃 t: borax; 〃 u: hexametaphosphoric acid; 〃 Example 3 Table 1, 100 parts by weight of binder of Experiment Nos. 1 to 13 and river sand 2
After 100 parts by weight are kneaded with a bread mixer for 3 minutes, the flow value
Tap water was added to 260 ± 20 mm, and fitting was performed for 5 minutes to prepare a mortar having a kneading temperature of 20 ± 2 ° C.

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;
And the mortar was prepared to form a lining layer having a thickness of 5mm at the conditions of 50G-5 min cast iron pipe surface of ¹⁰⁰ φ mm × 500 ^l mm by centrifugal molding machine by the method of Example 4 Example 3.

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 for 1 mm, and then 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.

To form a lining layer having a thickness of 8mm under the conditions of Example 5 Example by mortar centrifugal molding machine manufactured by 3 ways ^{200 φ mm × 500 l mm 50G} -5 min cast iron pipe surface of.

After completion of lining, put in a humidifier at 20 ° C and 100% RH and perform primary curing for 12 hours, then polish the surface to a predetermined thickness with a lathe, and further cure for 6 days under normal temperature air-drying conditions, and lining I got a tube.

The physical properties are shown in Table-5. The physical properties were measured in the same manner as in Example 1, and the amount of ion-exchanged water at the time of measuring the pH and soluble Al amount was set to 14.

Example 6 Portland cement (manufactured by Andes Cement) 100
Parts by weight and 200 parts by weight of river sand are kneaded with a pan-type mixer for 3 minutes, and then tap water is added in such an amount that a flow value of 210 ± 10 mm is obtained, and the mixture is kneaded for 5 minutes. Portland cement mortar was prepared. 50G-5 The mortar cast iron pipe surface of ²⁰⁰ φ mm × 500 ^l mm by centrifugal molding machine
For 5 minutes, a lining layer having a thickness of 5 mm was formed.

After completion of lining, leave at room temperature for 3 hours,
After steam curing at 4 ° C. for 4 hours, the surface was polished with a lathe to 1 mm. The Portland cement lining pipe was filled with the lining material of the present invention prepared by the method of Example 3 for 50 times.
G-5 mm lining was performed under the condition of 5 minutes, and the treatment after completion of the lining produced a two-layer lining tube according to Example 5.

In the comparative example, a portland cement mortar lining tube having a thickness of 8 mm produced by the method described above was used, and the measurement of the physical properties was performed according to Example 5. Table 6 shows the physical properties.

Example 7 5 parts by weight of chloroprene latex (trade name "Denka chloroprene LK-50"; manufactured by Denki Kagaku Kogyo KK) and 100 parts by weight of boric acid were added to 100 parts by weight of the binder obtained in Example 2, Experiment No. 2-16.
3 parts by weight are mixed with a small omni mixer for 55 minutes, and 100 parts by weight of this composition and 200 parts by weight of river sand are kneaded with a pan-type mixer for 5 minutes. In addition, mix for 10 minutes and mix the mortar with a kneading temperature of 20 ± 2 ° C by centrifugal molding machine at 60G for 5 minutes at ^100φ.
mm × 500 5mm thick lining KoTsuta the cast iron pipe of ^l mm. Processing after completion of the lining and measurement of physical properties were the same as those in Example 1.

The lining tube manufactured by this method is pH 8.0, soluble A
The l content was as good as 2.2 ppm, and no cracking was observed even after 55 days of material age.

〔The invention's effect〕

As is clear from the above, the lining tube manufactured according to the present invention can keep the initial water flow pH low without applying a seal coat, and can significantly reduce the amount of soluble Al as compared with the conventional lining tube using AC. .

Also, 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 binder comprising 30 to 95 parts by weight of alumina cement and 70 to 5 parts by weight of granulated blast furnace slag powder, and a lining material mainly composed of sand and water. 2. A method for manufacturing a lining pipe, comprising: lining the lining material according to claim 1 on the inner surface of the pipe by a centrifugal molding method; and curing the lining layer by humidifying curing. 3. 85 to 98 parts by weight of the binder according to claim 1,
A composition comprising 15 to 2 parts by weight of an inorganic expanding material and 0.1 to 5 parts by weight of a water reducing agent based on 100 parts by weight of a total of a binder and an inorganic expanding material, and a lining material mainly composed of sand and water. 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 humidifying curing.