JPH04270153A - Cement additive and pipe lined with the same - Google Patents

Abstract

PURPOSE:To provide a lined pipe rapidly, exhibiting a high strength, having employed especially in transporting liquids in construction and building fields, a method for producing the pipe, and a lining material used for producing the lined pipe. CONSTITUTION:A cement additive containing calcium aluminosilicate glass and an inorganic sulfate salt as main components; a lining material containing the cement additive, a cement and a fine aggregate; a pipe lined with the lining material; and a method for producing the lined pipe. The use of the cement additive in this invention gives the lined product having a high exhibited strength and has an effect to improve the production efficiency of the lined pipe.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to lined pipes used in the civil engineering and construction fields, particularly for transporting liquids.

0002

[Prior Art and its Problems] Conventionally, lined pipes have been manufactured by lining steel pipes or cast iron pipes with a lining material usually made of Portland cement or expanded cement, and then curing them with steam. However, in conventional manufacturing methods, steam curing steps such as preheating, heating, holding, and cooling usually involve
Since it takes more than 7 hours, it has been desired to improve productivity.

[0003] The present inventors investigated a lining material that can quickly develop strength without special steam curing after lining by centrifugal molding, and found that the above problem could be solved by using a specific composition. The present invention was completed based on the knowledge that it was possible to solve the problem and to obtain a product with very good strength development even at low temperatures.

0004

[Means for Solving the Problems] That is, the present invention is a cement admixture whose main components are calcium aluminosilicate glass and an inorganic sulfate, a lining material and a lining pipe using the same, and furthermore, This is the manufacturing method.

The present invention will be explained in detail below.

The calcium aluminosilicate glass (hereinafter referred to as CAS glass) according to the present invention preferably has a composition range of 30 to 60% by weight of CaO, 20 to 60% by weight of Al2O3, and 25 to 25% by weight of SiO.
More preferably 30-55% by weight, Al2O3 30-60% by weight, and 10-20% by weight SiO2. CaO is 3
If CaO is less than 0% by weight or Al2O3 is more than 60% by weight, rapid hardening tends to be poor. Conversely, if CaO is more than 60% by weight or Al2O3 is less than 20% by weight, a large amount of setting modifier may be added. Even if it is used, it will cause instantaneous condensation, which is unfavorable from the viewpoint of workability. In addition, SiO2 is 5% by weight
If it is less than 25% by weight, no long-term strength increase can be expected, and if it exceeds 25% by weight, the initial strength tends to be low.

[0007] General industrial raw materials include MgO, Fe
Impurities such as 2O3, TiO2, K2O, and Na2O are naturally included. Since these impurities expand the vitrification region of the CaO-Al2O3-SiO2 system, their presence is preferably less than 10% by weight, and they also cause problems in various properties such as rapid hardening, workability, and long-term strength growth. does not occur. In addition, when manufacturing CAS glass, NaNO, which is a common glass fluxing agent, is used.
Alkali nitrates such as 3 and KNO3, calcium fluoride,
It is preferable to add borax and the like because it lowers the melting point of the glass.

[0008] According to the definition of ASTM, the glass referred to herein is a molten inorganic substance that is cooled to a hard state without crystallization, and is hard and brittle, and forms shell-like cracks. They range from colorless and transparent to colored and transparent or opaque. In the present invention, it is "a substance exhibiting a glass transition point" determined from thermal analysis. It should be noted that it is not necessary that everything is glassy, and the vitrification rate is 5.
It is preferably 0% by weight or more, more preferably 70% by weight or more, and most preferably 80% by weight or more. If it is less than 50% by weight, the initial strength tends to be low. Note that the vitrification rate is determined by, for example, in the present invention, CAS glass is heated at 1000°C for 2 hours to melt it, and then
It was calculated according to Equation 1 from the area S0 of the main peak of crystalline minerals determined by powder X-ray diffraction method after slow cooling at a cooling rate of 5° C./min and the area S of the main peak of crystals in CAS glass.

[0009]

[Formula 1]

[0010] CAS glass has, for example, an average chemical composition of 40 to 43% by weight of CaO, 5 to 8% by weight of MgO,
Al2O3 13-15% by weight, and SiO231-35
The composition is completely different from the composition of granulated blast furnace slag, which is a by-product of metallurgy and metal smelting, which is a percentage by weight. Also, CAS
Glass has a completely different composition than alumina cement. That is, the amount of SiO2 in ordinary alumina cement is less than 5% by weight [Junichi Kasai, Concrete Engineering, Vol. 22, No. 8, p. 67 (1984)], and the vitrification rate is more than 25%. There is no [1964, published by City of London Academic Press Incorporated Limited, H. F. W. The Chemistry of Cement by Taylor
Chemistry of Cement), Volume 2,
Page 16].

Raw materials for producing CAS glass according to the present invention include CaO raw materials, Al2O3 raw materials, and SiO2 raw materials.
Examples include quality raw materials. As the CaO raw material, quicklime,
Slaked lime, limestone, etc., and Al2O3 raw materials include alumina, bauxite, diaspore, feldspar,
Furthermore, as the SiO2 raw material, silica sand, clay, diatomaceous earth, etc. can be used. Also,
Relatively cheap blast furnace slag, CaO raw material and Al2O3
It is also possible to supplement with quality raw materials.

The CAS glass according to the present invention has the above Ca
A method in which O-based raw materials, Al2O3-based materials, and SiO2-based materials are blended in a predetermined ratio, melted using a direct current melting furnace, high-frequency furnace, etc., and the resulting melt is blown away with compressed air or high-pressure water. Alternatively, it can be manufactured by pouring it into water. Furthermore, it can also be produced by melting it in a rotary kiln and rapidly cooling it. The finer the powder size of CAS glass, the better the reactivity is, and in particular, the Blaine specific surface area is 3,
000 cm2/g or more is preferable.

The inorganic sulfate according to the present invention is an alkali metal or alkaline earth metal sulfate, and among these, anhydrous, hemihydrate and dihydrate calcium sulfates are preferred, and type II anhydrous gypsum is particularly preferred. The fineness of inorganic sulfate is 2,000 to 8,000 cm in Blaine specific surface area.
About 2/g is preferable. The amount of inorganic sulfate used is CAS
It is preferably 50 to 300 parts by weight, more preferably 100 to 200 parts by weight, based on 100 parts by weight of glass. If it is less than 50 parts by weight, it is unfavorable in terms of strength development, and if it exceeds 300 parts by weight, it exhibits expansivity and tends to cause cracks and reduce strength.

In the present invention, a cement admixture containing CAS glass and an inorganic sulfate as main components is mixed with cement as a rapid hardening material to develop the initial strength of the lining material.

[0015] The cement according to the present invention includes various types of Portland cement, various mixed cements in which blast furnace slag, fly ash, or silica are mixed with them, and special cements such as moderate heat cement, white cement, and colloidal cement. can be mentioned.

In the present invention, the amount of cement admixture used is preferably 10 to 50 parts by weight per 100 parts by weight of cement. If it is less than 10 parts by weight, the initial strength will not be sufficiently developed, and if it exceeds 50 parts by weight, the long-term properties such as dimensional stability of the lining material may be impaired.

The fine aggregate according to the present invention is not particularly limited, but sea sand, mountain sand, river sand, etc. can be used. Among these, those containing less alkali salts are preferred. In the present invention, the amount of fine aggregate used is 100 parts by weight in total of cement and cement admixture.
It is preferably 500 parts by weight, and more preferably 150 to 300 parts by weight from the viewpoint of strength development and durability.

Further, in the present invention, it is also possible to use other admixtures commonly used in mortar and concrete. Other admixtures include, for example, setting modifiers, fibers such as glass fibers, carbon fibers, and steel fibers;
Polymer emulsions, latex, colorants, AE agents,
Water reducing agents, AE water reducing agents, fluidizing agents, rust preventives, water retaining agents such as methylcellulose, waterproofing agents such as calcium chloride and sodium silicate, foaming agents, foaming agents, calcium salts such as calcium hydroxide, and antifreeze agents. etc., and one or more of them can be used in combination in an amount that does not substantially inhibit the object of the present invention.

The setting modifier is used when the CAS glass has a high CaO content and the setting time is fast. here,
As setting regulators, citric acid, tartaric acid, gluconic acid,
Organic acids such as succinic acid and maleic acid or their salts, alkali carbonates such as sodium carbonate and potassium carbonate,
Examples include phosphoric acids or their salts, boric acid, alkali borates, alkali aluminates, fluorosilicides, starches, sugars, alcohols, and mixtures thereof, among which organic acids are preferably used. The amount of the setting modifier used is preferably about 1 to 30 parts by weight per 100 parts by weight of the CAS glass in order to obtain an appropriate pot life of about 20 to 240 minutes, for example.

[0020] The cement admixture and lining material mixing device of the present invention is not particularly limited, but for example,
Tilt mixer, Omni mixer manufactured by Chiyoda Giken Kogyo Co., Ltd.
Any existing stirring device can be used, such as V-mixers, Henschel mixers, and Nauter mixers. In addition, the method of mixing each material is not particularly limited;
Each material may be mixed at the time of construction, or some or all of the materials may be mixed in advance.

The steel pipe used in the present invention is usually a steel pipe or a cast iron pipe, and the type is not particularly limited as long as a lining layer can be formed by centrifugal forming.

The lining method is not particularly limited, and can be carried out in the same manner as centrifugal molding of ordinary cement mortar. In other words, while rotating a steel pipe set in a centrifugal forming machine, lining material is continuously and/or discontinuously introduced, and the inner surface of the pipe is lined by centrifugal force. rear,
It is common to remove free water and then compact the material with a force of about 1 to 50G.

[0023] The lining layer may be not only one layer but also a multilayer of two or more layers, and its thickness is usually about 2 to 20 mm, although it depends on the diameter of the steel pipe.

[0024]

EXAMPLES The present invention will be explained in more detail below.

Example 1 A mortar having the composition shown in Table 1 was prepared using 100 parts by weight of cement and 45 parts by weight of water for a total of 100 parts by weight of cement and cement admixture. The pot life was measured. The materials used and test methods are as follows. The results are also listed in Table 1. Note that the units in Table 1 are parts by weight.

[0026]

[Table 1]

<Materials used> Cement: Ordinary Portland cement manufactured by Andes Cement Co., Ltd. CAS glass A: CaO/Al2O3/
Weight ratio of SiO2 is 50/40/10, vitrification rate is 10
0%, Blaine specific surface area 4,00
0cm2/g 〃 B:CaO/Al2O3/
SiO2=40/40/20, vitrification rate 100%, Blaine specific surface area 4,500cm2
/g 〃 C:CaO/Al2O3/SiO2
=30/45/25, vitrification rate 100%, Blaine specific surface area 4,900 cm2/g Inorganic sulfate: Type II anhydrous gypsum, Blaine specific surface area 5.9
00cm2/g fine aggregate Material: Natural sand 2 from Himekawa, Niigata Prefecture
．． 5mm lower setting regulator: Denki Kagaku Kogyo Co., Ltd. trade name “Denka ES Setter” main ingredient oxycarbon
acid

(Test method) Compressive strength: Measured according to JIS R 5201. However, the curing conditions are 20℃65%RH and 5℃65%RH.
It is RH. Pot life: The time it takes to harden and lose its fluidity. After mixing all the materials with a mixer, they were placed in a 500 cc beaker and allowed to stand for a period of time until it stopped flowing even when laid down.

Example 2 Example 1, Experiment No. 1-9 mortar, 200r
Rotating at pm inner diameter 200mm, length 600mm,
It was poured into a cast iron pipe with a thickness of 5 mm, and the surface was leveled. Next, the rotation of the cast iron pipe was increased to 800 rpm, and after rotating for 2 minutes, the rotation was stopped, and the mortar surface was drained to obtain a mortar-lined pipe. The thickness of the lining layer is 5
mm, and the condition of the lining was good.

[0030] Next, this mortar lining pipe was
After curing for one week at ℃80%RH, the length is 200m.
cut into 10 m, immersed in water, exposed outdoors, and CO2 gas 10
% by volume, and under each curing condition of 40° C. and 80% RH, and the condition was observed. The results are shown in Table 2.

[0031]

[Table 2]

As shown in Table 2, under each condition, no peeling of the lining layer, no cracking, and no rusting on the inner surface of the tube was observed.

[0033]

[Effects of the Invention] By using the cement admixture of the present invention, a lining material with good initial strength development can be obtained without steam curing, and the production efficiency of lined pipes can be improved. .

Claims (4)

[Claims] [Claim 1] A cement admixture whose main components are calcium aluminosilicate glass and inorganic sulfate. 2. A lining material comprising the cement admixture according to claim 1, cement, and fine aggregate. 3. A lined pipe comprising a lining layer made of the lining material according to claim 2 on the inner surface of the steel pipe. 4. A method for manufacturing a lined pipe, which comprises performing centrifugal molding using the lining material according to claim 2, and lining the inner surface of the steel pipe with a lining layer made of the lining material according to claim 2.