JPH07291693A - Concrete product and its production - Google Patents

Abstract

PURPOSE:To enable the production of a concrete product such as a high strength Hume concrete pipe or a thin type box culvert by comprising anhydrous gypsum in an expanded material produced by the heat treatment of a mixture of a CaO raw material with a CaF2 raw material. CONSTITUTION:This concrete product is formed of a concrete obtained by blending an expanded material, produced by the heat treatment of a mixture of a CaO raw material with a CaF2 raw material, and comprising by a mineral containing CaO and CaF2 as active components with a CaF2 content therein of 10-50 pts.wt. based on 100 pts.wt. total amount of the CaO and CaF2 with a cement admixture containing an anhydrous gypsum. The raw materials used for the expanded material can optionally be selected according to the purity or cost; however, e.g. a CaCO3 matter such as a lime stone or a slacked lime, and Ca(OH)2 matter, are cited as the CaO raw material and e.g. a naturally produced fluorite or CaF2 as an industrial byproduct are cited as CaF2 raw material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to concrete products such as high-strength fume tubes and thin box culverts used in the civil engineering and construction industry.

[0002]

2. Description of the Related Art Conventionally, for example, concrete pipes, such as concrete pipes such as fume pipes and box culverts, piles, poles, and concrete products such as steel pipe concrete composites, are generally produced by using ordinary Portland cement as a main material. (Concrete Engineering Handbook, published by Asakura Shoten).

Here, the fume pipe is a reinforced concrete pipe in which a form filled with concrete is rotated at a high speed and is compacted by utilizing centrifugal force. Is a generic name for propulsion pipes and seamless pipes that have been deformed, and in particular, high-strength fume pipes are made by using expansive concrete in which an expansive cement admixture is mixed with an appropriate amount of cement and introducing chemical prestress. The high-strength Hume tube means a Type 2 or Type 3 Hume tube, and specifically, the Type 2 Hume tube has a cracking strength about twice that of the Type 1 Hume tube. 3 types of Hume tube is about 3 of 1 type Hume tube
It has double the crack strength.

However, the method of introducing the chemical prestress has a problem that it is not possible to introduce a sufficient chemical prestress in the concrete containing the latent hydraulic substance. There is also a problem that the product value is impaired, such as expansion cracks occurring at the end of the pipe where the binding force does not work.

On the other hand, the box culvert is a reinforced concrete product having a box-shaped cross section for underdrain, and particularly compared with a reinforcement concrete structure (RC structure) using deformed rebar specified in JIS G 3112. The RC box culvert with a cross-section wall thickness of 20-40% is thin RC
Box culvert. In this way, the thin RC box culvert has a product weight 20 to 40% lighter than that of a normal RC box culvert, so that transportation costs and construction machinery can be saved, and the cross-sectional thickness can be reduced. It has advantages such as reduction of excavated soil and reduction of material cost for mountain retaining works. Conventionally, in order to manufacture thin box culverts, high strength concrete with a unit cement amount of 480 kg / m ³ and a water / cement ratio of about 32% by weight was compounded, and after the concrete was hardened, prestress was introduced by a mechanical method. A prestressed concrete construction method (PC construction method) for increasing bending tensile resistance, or a construction method for increasing bending tensile resistance by using high-strength reinforcing bars is used. However, the PC construction method requires a large amount of materials for the PC construction method and the machine introduction cost, and the construction method using the high-strength reinforcing bars requires the use of expensive high-strength reinforcing bars. There were issues such as high costs.

The present inventor has conducted extensive studies in order to solve the above-mentioned problems, and as a result, only by curing concrete mixed with a specific cement admixture, even if ordinary deformed reinforcing bars are used, the conventional method is used. The inventors have completed the present invention by finding that it is possible to manufacture concrete products such as high-strength fume pipes and thin box culverts having a quality equal to or higher than that of the above.

[0007]

[Means for Solving the Problems] That is, the present invention provides a CaO source.
Fees and CaF₂Expanded material produced by heat-treating a mixture containing raw materials
Quality, CaO and CaF₂Made from minerals containing
And CaF in the mineral ₂But CaO and CaF₂Total 100 weight
10 to 30 parts by weight of the expansive substance, and anhydrous gypsum
Concrete mixed with cement admixture containing
Is a concrete product formed by molding
And amorphous calcium aluminate and anhydrous gypsum
Concrete mixed with cement admixture containing
Is a concrete product formed by molding
High strength fume tube or thin RC box car
And the concrete product.
Is a manufacturing method.

The present invention will be described in more detail below.

The raw material of the expansive substance used in the present invention can be arbitrarily selected depending on the purity and cost and is not particularly limited. For example, the CaO raw material is CaCO such as limestone or slaked lime. ₃ quality and Ca (OH) ₂ quality,
In addition, examples of the CaF ₂ raw material include fluorite naturally produced and CaF ₂ as an industrial by-product. The mixing of impurities such as SiO ₂ , Fe ₂ O ₃ , CaSO ₄ , MgO, and TiO ₂ existing in the raw material is not particularly limited as long as it does not substantially impair the object of the present invention.

The blending ratio of the raw materials in the present invention is such that CaF ₂ is CaO and CaF ₂ as the chemical composition of the expanding substance as a product.
It is necessary to make it 10 to 30 parts by weight, and 15 to 25 parts by weight is preferable. If the amount of CaF ₂ is less than 10 parts by weight, for example, the material exhibits a rapid expansion property by the first day of age, and cracks may occur in the part of the hardened cement using the expanded material where the binding force does not work, and strength development May decrease, and when CaF ₂ exceeds 30 parts by weight, strength development, expandability, and prestress introduction amount tend to decrease.

In the present invention, since the decomposition temperature of CaF ₂ largely changes depending on the blending ratio of the raw material mixture and the content of impurities, the firing temperature during firing is not particularly limited. Is preferably about 1,000 to 1,450 ° C.
The method of mixing the raw materials is not particularly limited, and an ordinary method can be used. The heat treatment method for producing the expanded substance is not particularly limited, and for example, any method such as firing with a rotary kiln or melting with an electric furnace is possible.

The particle size of the expansive substance is not particularly limited because it depends on the purpose and application of use, but a Blaine value of 1,500 to 8,000 cm ² / g is preferable. If it is less than 1,500 cm ² / g, the strength developability tends to deteriorate, and if it exceeds 8,000 cm ² / g, the expandability may not be sufficiently exhibited.

The amount of the expansive substance used is 5 per 100 parts by weight of the cement admixture consisting of the expansive substance and anhydrous gypsum described below.
0 to 90 parts by weight is preferable, and 60 to 80 parts by weight is more preferable. If it is less than 50 parts by weight, the expandability may decrease,
If it exceeds the weight part, the strength development effect may not be sufficiently obtained. Further, when using the below-mentioned amorphous calcium aluminate in combination, in the cement admixture 100 parts by weight of expansive substance, amorphous calcium aluminate, and anhydrous gypsum, preferably 50-80 parts by weight, 55-65 More preferably parts by weight. If it is less than 50 parts by weight, the swelling property may decrease, and if it exceeds 80 parts by weight, the effect of developing strength may not be sufficiently obtained.

The anhydrous gypsum used in the present invention is not particularly limited, and naturally-occurring natural anhydrous gypsum, anhydrous gypsum obtained by heat-treating hemihydrate gypsum or dihydrate gypsum, and industrial gypsum are produced. Anhydrous gypsum or the like can be used. The particle size of anhydrous gypsum is not particularly limited, but the Blaine value is 2,500 to 9,000 cm ² /
g is preferred. If it is less than 2,500 cm ² / g, long-term durability may be deteriorated, and if it exceeds 9,000 cm ² / g, expandability may not be sufficiently exhibited.

The amount of anhydrous gypsum used is from 10 to 50 in 100 parts by weight of the cement admixture consisting of the expansive substance and anhydrous gypsum.
Weight part is preferable, and 20-40 weight part is more preferable. If it is less than 10 parts by weight, the amount of chemical prestress introduced may be small, a sufficient strength manifesting effect may not be obtained, and the end portion where the restraining force does not work may cause expansion failure.
If it exceeds the weight part, the expandability may become insufficient or the amount of prestress introduced may become small. Further, when using the amorphous calcium aluminate in combination, in the cement admixture 100 parts by weight of expansive substance, amorphous calcium aluminate, and anhydrous gypsum, preferably 10 to 40 parts by weight, 20 to 30 parts by weight. Is more preferable. Below 10 parts by weight,
If the amount of chemical pre-stress introduced is small, sufficient strength development effect may not be obtained, or the end part where the binding force does not work may cause expansion failure, and if it exceeds 40 parts by weight, expandability will be insufficient. In some cases, the amount of prestress introduced may decrease.

The amorphous calcium aluminate used in the present invention preferably has a CaO content of 35 to 45% by weight. If the CaO content is less than 35% by weight, the expandability and strength development may be insufficient, or sufficient cracking strength may not be obtained, and if it exceeds 45% by weight, the fluidity will decrease and the workability will deteriorate. It may get worse. Amorphous calcium aluminate is obtained by melting a CaO raw material and an Al ₂ O ₃ raw material and quenching the resulting clinker. Although the melting temperature of the amorphous calcium aluminate varies depending on impurities, it is usually preferably 1,500 to 1,700 ° C. The particle size of the amorphous calcium aluminate is not particularly limited, but the Blaine value is preferably 1,500 to 6,000 cm ² / g. If it is less than 1,500 cm ² / g, sufficient expandability and crack strength may not be obtained, and if it exceeds 6,000 cm ² / g, workability may deteriorate.

The amount of the amorphous calcium aluminate used is 5 to 2 in 100 parts by weight of the cement admixture consisting of the expansive substance, the amorphous calcium aluminate, and anhydrous gypsum.
5 parts by weight is preferable, and 10 to 20 parts by weight is more preferable. If the amount of amorphous calcium aluminate used is not within this range, sufficient crack strength may not be obtained.

The particle size of the cement admixture of the present invention depends on the purpose and application to be used and is not particularly limited, but it is usually used in the range of 1,500 to 8,000 cm ² / g in terms of Blaine value. preferable. If it is less than 1,500 cm ² / g, the strength developability may be adversely affected, and if it exceeds 8,000 cm ² / g, the expandability may not be sufficiently exhibited.

The amount of the cement admixture of the present invention varies depending on the purpose of use, but when the cement admixture comprises an expansive substance and anhydrous gypsum, the total amount of the cement and the cement admixture (hereinafter referred to as binder) is 100% by weight. 3 to 15 parts by weight is preferable, and 5 to 12 parts by weight is more preferable. If it is less than 3 parts by weight, the expandability and the amount of prestress introduced are not sufficient,
If it exceeds 15 parts by weight, abnormal expansion may occur, and an increase in use effect cannot be expected. In addition, cement admixture,
When the expansion substance, amorphous calcium aluminate, and anhydrous gypsum are used, the cement admixture is preferably 3 to 20 parts by weight, more preferably 5 to 15 parts by weight, in 100 parts by weight of the binder. If it is less than 3 parts by weight, the expandability and the amount of prestress introduced are not sufficient, and if it exceeds 20 parts by weight, abnormal expansion may occur, and an increase in use effect cannot be expected.

As cement, normal, early strength, super early strength,
And various portland cements such as moderate heat, various mixed cements obtained by mixing a pozzolanic substance such as blast furnace slag or silica with these portland cements, and alumina cements. The cement admixture of the present invention is particularly effective when used in combination with mixed cement.

In the present invention, the amount of water used is not uniquely determined by the kind and amount of the material used, but usually, the water / binder ratio is preferably 25 to 50% by weight, -40% by weight is more preferred. Below 25% by weight,
Sufficient workability may not be obtained in some cases, and if it exceeds 50% by weight, sufficient strength development may not be obtained. Also,
The properties of concrete kneaded with such kneading water are:
For example, in the case of centrifugal force molded products such as fume tubes, piles, and poles, it is better to use relatively hard concrete with a slump value of about 2 to 8 cm to suppress slag that occurs during centrifugal force molding and material separation. From the viewpoint of resistance, U
For character-shaped concrete, box culvert, and the like, it is preferable to use relatively soft concrete having a slump value of about 10 to 22 cm from the viewpoint of improving the filling property.

In the present invention, in addition to cement and cement admixture, a setting regulator, a water reducing agent, a high performance water reducing agent, an AE agent, A
E water reducing agent, high performance AE water reducing agent, thickener, aggregate such as sand and gravel, cement rapid hardening material, rust inhibitor, antifreeze, polymer emulsion, clay mineral such as bentonite, zeolite, hydrotalcite, And one or more of ion exchangers such as hydrocalumite, inorganic sulfates such as aluminum sulfate and sodium sulfate, inorganic phosphates, and boric acid do not substantially inhibit the object of the present invention. It can be used in combination within a range.

In the present invention, the method of mixing the respective materials is not particularly limited, and the respective materials may be mixed at the time of construction, or part or all of them may be mixed in advance. . As the mixing device, any existing stirring device can be used, and for example, a tilting barrel mixer, an omni mixer, a V-type mixer, a Henschel mixer, a Nauta mixer, or the like can be used.

The method for molding a concrete product according to the present invention comprises:
It is not particularly limited as long as concrete can be normally filled in the form. For example, in the case of fume pipes, piles, poles, etc., the centrifugal force forming method is generally performed, and U-shaped concrete or box culverts are used. For example, there is a method in which vibration is applied by a vibrator to perform compaction, or the concrete itself is fluidized to be concrete that does not need to be compacted, and is poured by pouring. The method for molding a centrifugal force molded product is not particularly limited, and for example, it is common to fill concrete with a slump of about 5 cm and perform centrifugal force molding, and usually an acceleration of about 1 to 50 G is applied. In many cases, centrifugal force molding is performed, and centrifugal force molding is also performed in three or four stages of low speed, medium speed, and high speed during molding.

The curing method for producing the concrete product of the present invention is not particularly limited, and includes, for example, normal temperature / normal pressure curing, heating curing, pressure curing, steam curing, and high temperature curing. Although any curing method such as high-pressure steam curing (autoclave curing) can be applied, it is preferable to use a method of heating while preventing moisture depletion and promoting hydration of cement, like steam curing and autoclave curing. .
It is also possible to cover the part exposed from the mold with a sheet or the like. Here, as the heating conditions, for example, it is general to carry out curing in three stages of temperature raising, heat retaining, and cooling, and the temperature raising rate is usually preferably about 5 to 25 ° C./hour, It is more preferably about 20 ° C / h. If it is less than 5 ° C / h, the curing time will be long and it will be uneconomical.
If it exceeds h, the dimensional stability may deteriorate. Also,
The heat retention is not particularly limited and is usually 40 to 80 ° C.
It is about 50 to 70 ° C, and more preferably about 50 to 70 ° C. If it is lower than 40 ° C, sufficient strength development may not be obtained, and if it exceeds 80 ° C, dimensional stability may be deteriorated. The heat retention time is usually preferably about 1 to 10 hours, more preferably 2 to 8 hours. If it is less than 1 hour, sufficient strength development may not be obtained, and if it exceeds 10 hours, dimensional stability may be deteriorated. In addition, the cooling rate is preferably 30 to avoid rapid cooling, such as natural cooling.
It is preferable that the cooling rate is not more than ° C / h. 30 ° C / h
If it exceeds the range, the concrete tends to crack. When performing steam curing or autoclave curing, after filling the kneaded concrete into the form,
It is preferable to perform pre-curing at room temperature for about 3 to 8 hours. If pre-curing is not performed, strength development and dimensional stability may deteriorate. The concrete product in the present invention is generally cured even after demolding, and normally, like underwater curing, sprinkling curing, and compress curing, it is possible to carry out curing while preventing moisture depletion, and strength development occurs. It is preferable from the viewpoints of properties and dimensional stability.

The method of arranging may be the same as that of the conventional box culvert or the Hume tube of RC structure, and the kneading method may be a commonly used method and is not particularly limited.

[0027]

The present invention will be described in detail below with reference to examples.

Example 1 Limestone powder was used as a CaO raw material and fluorspar was used as a CaF ₂ raw material, and the mixture was fired at a maximum firing temperature of 1,300 ° C. using a rotary kiln to obtain a clinker. It was crushed and adjusted to a brain value of 3,000 ± 200 cm ² / g to obtain an expanded substance. Each unit amount is 500kg / m ^{3 of} binder, 708kg / m ^{3 of} fine aggregate,
Coarse aggregate 953kg / m ^3, and the water 193 kg / m ^3, in the binder to 100 parts by weight of a cement admixture composed of expanded material 70 parts by weight of anhydrous gypsum 30 parts by weight, 7 parts by weight were blended, the concrete kneaded product I kneaded it. Using kneaded concrete,
φ1,200mm, L2,430mm fume tube, standard value is 8,400k
A gf / m type 3 tube was centrifugally molded. Centrifugal force molding conditions are 20
A low speed of 0 rpm was 2 minutes, a medium speed of 350 rpm was 2 minutes, and a high speed of 600 rpm was 6 minutes. After centrifugal molding, pre-curing was carried out at room temperature for 4 hours, the molded fume tube was heated at a heating rate of 16 ° C./h, steam-cured at 65 ° C. for 4 hours, and naturally cooled. The mold was demolded 24 hours after the completion of concrete kneading, and thereafter, sprinkling curing was carried out for 6 days, and the crack strength on the 7th day of age was measured. The results are shown in Table 1.

<Materials used> CaO raw material: Limestone powder from the Omi mine of Denki Kagaku Kogyo Co., Ltd.,
4,230cm _² / g CaF ² material: Matsushita minerals manufactured natural fluorite powder inflation material A: total of 100 parts by weight of CaO and CaF _2, CaF ₂ 5 parts by inflation material B: CaO and a total of 100 parts by weight of CaF ₂ Medium, CaF ₂ 10 parts by weight Expansion material C: CaO and CaF ₂ total 100 parts by weight, CaF ₂ 20 parts by weight Expansion material D: CaO and CaF ₂ total 100 parts by weight CaF ₂ 30 parts by weight Expansion material E : CaF ₂ 35 parts by weight in total 100 parts by weight of CaO and CaF ₂ Expansion material F: Denka CSA product name "DENKA CSA"
# 20 ", conventional product Anhydrous gypsum: Natural anhydrous gypsum cement α: Denki Kagaku Kogyo's ordinary portland cement Coarse aggregate: Niigata prefecture Himekawa, Gmax = 15mm, specific gravity 2.67 Fine aggregate: Niigata prefecture Himekawa, specific gravity 2.63 Water : Tap water The composition of the expansive substance is CaO and F according to JIS R 5202.
Analyzing the ₂ amount was determined in further converted the F ₂ amount to CaF _2.

<Test method> Crack strength: The crack strength σ _bt is σ _bt = M / 20t ² , M = 0.318P _cr +0 from the crack load P _cr of the fume tube.
238W · r, where M is the bending moment (kgf / cm) that occurs at the bottom of the pipe when an external pressure test load is applied, t is the pipe thickness (cm), P _cr is the cracking load (kgf / m), and W is the pipe's own weight ( kgf / m), r is the radius (cm) to the center of the pipe thickness.

[0031]

[Table 1]

Example 2 Example 2 was repeated except that cement β, which was blast furnace cement, was used as the cement. The results are shown in Table 2.

<Materials used> Cement β: Blast furnace cement type B manufactured by Denki Kagaku Kogyo Co., Ltd.

[0034]

[Table 2]

Example 3 The same procedure as in Example 2 was carried out except that the expanding material C was used and the particle size of the expanding material was changed as shown in Table 3. The results are shown in Table 3.

[0036]

[Table 3]

Example 4 The same procedure as in Example 2 was carried out except that the expanding substance C was used and the amount of anhydrous gypsum used in 100 parts by weight of the cement admixture was changed. The results are shown in Table 4.

[0038]

[Table 4]

Example 5 As shown in Table 5, 60 parts by weight of expansion material, 15 parts by weight of amorphous calcium aluminate (A-CA), and anhydrous gypsum 25
The same procedure as in Example 1 was performed, except that the cement admixture consisting of 10 parts by weight was used in 100 parts by weight of the binder. The results are shown in Table 5.

<Materials to be used> A-CAi: A mixture of calcium carbonate of a first grade reagent and aluminum oxide having a molar ratio of 10: 8 was melted at 1,650 ° C. and rapidly cooled, and the clinker obtained was ground to give a brane. value
It was set to 3,410 cm ² / g. CaO content 41% by weight

[0041]

[Table 5]

Example 6 Example 5 except that cement β was used as the cement.
I went the same way. The results are shown in Table 6.

[0043]

[Table 6]

Example 7 A cement admixture 100 was prepared using expansion substances C and A-CAi.
By changing the amount of anhydrous gypsum in the parts by weight, the expansion material and AC
Example 6 was repeated except that the amount of A was increased / decreased in equal amounts to keep the amount of cement admixture constant. The results are shown in Table 7.

[0045]

[Table 7]

Example 8 Using expansion material C, A in 100 parts by weight of cement admixture
Example 6 was repeated except that the type and amount of CA was changed and the amounts of the expanding substance and anhydrous gypsum were increased and decreased in equal amounts to keep the amount of cement admixture constant. The results are shown in Table 8.

<Materials used> A-CA: A mixture of calcium carbonate of the first grade reagent and aluminum oxide in a molar ratio of 10:11 was melted at 1,650 ° C. and rapidly cooled, and the clinker obtained was crushed to give a brane. value
It was set to 3,010 cm ² / g. CaO content 33% by weight A-CA Ha: A mixture of calcium carbonate of the first grade reagent and aluminum oxide having a molar ratio of 10:10 was melted at 1,650 ° C. and rapidly cooled, and the clinker obtained was ground to give a Blaine value.
It was set to 3,150 cm ² / g. CaO content 35% by weight A-CA: A mixture of calcium carbonate and aluminum oxide of reagent grade 1 at a molar ratio of 10: 7 was melted at 1,650 ° C. and rapidly cooled, and the clinker obtained was ground to give a Blaine value.
It was set to 3,090 cm ² / g. CaO content 44% by weight A-CAho: A mixture of calcium carbonate and aluminum oxide in the reagent grade 1 at a molar ratio of 10: 6 was melted at 1,650 ° C. and rapidly cooled, and the clinker obtained was ground to give a Blaine value.
It was set to 2,980 cm ² / g. CaO content 48% by weight

[0048]

[Table 8]

Example 9 Cement and cement admixture were used as in Example 1,
Amount units, each binder 480 kg / m ^3, fine aggregates 680 kg / m ^3, the coarse aggregate 1,085kg / m ^3, and water 150 kg / m ^3, furthermore, the binder 10
A concrete mixture prepared by mixing 1 part by weight of a high-performance water reducing agent with 0 part by weight of water and replacing it with JIS G
Placing the deformed rebars of 10mm and 13mm specified in 3112 on the formwork laid out by the usual method, the dimensions are 1,200 × 1,500mm, and the thickness is 100mm.
Molded a thin RC box culvert with a design load of 10.4 tons. The formed thin RC box culvert is heated for 4 hours at a heating rate of 16 ° C / h and then at 65 ° C for 4 hours.
The steam was cured for a period of time, naturally cooled, and the crack strength was measured for 7 days. The results are also shown in Table 9. For comparison, Table 9 also shows the results obtained by the PC method and the conventional method using high-strength reinforcing bars without adding the cement admixture. In addition, when the cement admixture is added in the conventional method using the PC method or high-strength reinforcing bars, the opposite effect is obtained.

<Materials used> Water reducing agent: "Denka FT-500G" manufactured by Denki Kagaku Kogyo Co., Ltd.
Main ingredient naphthalene

<Test method> Cracking strength: Two-point pin support under the neutral axis of the side wall of the bottom plate, one-point loading at the center of the top plate

[0052]

[Table 9]

Example 10 The same procedure as in Example 9 was carried out except that cement β was used as the cement. The results are shown in Table 10.

[0054]

[Table 10]

Example 11 The procedure of Example 10 was repeated except that the expanding material C was used and the particle size of the expanding material was changed as shown in Table 11. The results are shown in Table 11.

[0056]

[Table 11]

Example 12 Example 12 was repeated except that the cement admixture used in Example 5 was mixed in 10 parts by weight in 100 parts by weight of the binder. The results are shown in Table 12.

[0058]

[Table 12]

Example 13 Example 1 except that cement β was used as the cement.
The same procedure as 2 was performed. The results are shown in Table 13.

[0060]

[Table 13]

[0061]

As the cement product of the present invention, it is possible to manufacture a fume tube having a large crack strength and a thin box culvert having a large crack load resistance as compared with conventional products.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C04B 22/14 B E03F 3/04 F16L 9/08 // (C04B 28/00 22:12 22: 08 Z 22:14) B 103: 60 111: 20 (72) Inventor Yoshihisa Matsunaga 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata Prefecture Inside the Aomi Plant of Denki Kagaku Kogyo Co., Ltd.

Claims (5)

[Claims] 1. CaO raw material and CaF₂Heat treatment of mixture containing raw materials
CaO and CaF₂Effective
CaF contained in the mineral ₂But CaO
And CaF₂Of 10 to 30 parts by weight in total 100 parts by weight of
Cement admixture containing quality and anhydrous gypsum
Made of concrete by molding the mixed concrete
Goods. 2. CaO raw material and CaF₂Heat treatment of mixture containing raw materials
CaO and CaF₂Effective
CaF contained in the mineral ₂But CaO
And CaF₂Of 10 to 30 parts by weight in total 100 parts by weight of
Quality, amorphous calcium aluminate, anhydrous gypsum
Concrete containing a cement admixture containing
A concrete product made by molding a toe. 3. A high-strength fume tube obtained by molding the concrete according to claim 1 or 2. 4. A thin RC box culvert formed by molding the concrete according to claim 1 or 2. 5. The concrete according to claim 1 or 2,
A method for producing a concrete product, which comprises filling in a mold, molding, and curing.