JPH0834652A - Concrete composition and concrete - Google Patents

Abstract

PURPOSE:To obtain a high-strength concrete high in fluidity and low in slump loss by incorporating cement, fly ash, aggregate and a copolymer of a specified polyoxyakylene deriv. and maleic acid anhydride. CONSTITUTION:In the vol. of concrete of 1m3, (A) 200-500kg cement, (B) 50-300kg fly ash,(C) 100-185kg water, (D) 400-1200kg (E) 400-1200kg coarse agreegate, and 0.1-10kg additive consisting of the copolymer obta. by copolymerizing (F) a polyoxyalkylene deriv. expressed by formula R<1>O)AO)nR<2> (R<1> is 2-5C alkeny1, AO is 2-4C oxyalene and >=50% there of is oxyethylene, (n)is 10-50 and R<2> is 1-8C hydrocarbon radical) and (G) maleic acid anhydride in a system of <=1wt.% water content based on the total amount of F and G components, hydrolyzed matter thereof or its salt are compounded, and other additive, an antifoaming agent, an air entraining agent, etc., are added at need to be kneaded and put into a formwork.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel concrete composition. More specifically, the present invention relates to a concrete composition containing fly ash, which has excellent slump loss prevention properties and high strength.

[0002]

2. Description of the Related Art In addition to the characteristics that concrete has a strong hardening power, it can be shaped freely, and it has excellent fire resistance and corrosion resistance, it can be mass-produced, is cheap and easy to use, and is easy to use. Since it has many excellent characteristics as a product, it is not used as a construction material at present and is used in large quantities. In recent years, with the increase in the thickness and size of concrete structures, there has been an increasing demand for higher strength of concrete. In order to increase the strength of concrete, it is necessary to increase the hydraulic components such as cement in the concrete composition and decrease the water content, but since the viscosity after mixing the concrete composition increases, a water reducing agent. And other additives are required. Furthermore, with the development of highly fluidized concrete, the performance requirements for water reducing agents have become even higher. As the water reducing agent, a naphthalenesulfonic acid formaldehyde condensate salt,
Melamine sulfonic acid formaldehyde condensate salts, lignin sulfonic acid salts, polycarboxylic acid compounds and the like are used. The naphthalene sulfonic acid formaldehyde condensate salt and the melamine sulfonic acid formaldehyde condensate salt have a large slump loss, and the water reducing property cannot be said to be sufficient. Lignin sulphonate has insufficient water reduction. Therefore, a polycarboxylic acid type water reducing agent is often used. On the other hand, as one of the reuses of industrial waste, fly ash generated from a coal-fired power plant or the like is used as a part of a concrete composition.
However, the amount used is only a small part of the generated fly ash, and more use is desired. When fly ash is used as a part of the concrete composition, even when using the above-mentioned polycarboxylic acid-based water reducing agent, there is a drawback that the slump loss becomes large, which is sufficient use of fly ash. Has not become one of the causes. Therefore, there is a demand for the development of a concrete composition that does not increase the slump loss even when a large amount of fly ash is mixed and that maintains high strength.

[0003]

The present invention has been made for the purpose of providing a concrete composition containing a large amount of fly ash, having high fluidity after mixing, little slump loss, and high strength concrete. It is a thing.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that fly ash, a specific polyoxyalkylene derivative and maleic anhydride are treated by a specific method. It was found that a concrete composition containing a copolymerized copolymer has high fluidity after mixing, has little slump loss, and gives high strength concrete, and completes the present invention based on the findings. Came to. That is, the present invention is (1) concrete 1m
^{In 3} , (A) cement 200-500 kg, (B) fly ash 50-300 kg, (C) water 100-185 kg,
(D) Fine aggregate 400 to 1200 kg, (E) Coarse aggregate 400
To 1200 kg, and (F) the following general formula [1] R ¹ O (AO) _n R ² ... [1] (wherein R ¹ is an alkenyl group having 2 to 5 carbon atoms, AO is 2 to 4 carbon atoms). An oxyalkylene group of n = 10 to 50,
R ² represents a hydrocarbon group having 1 to 8 carbon atoms. Further, 50 mol% or more of the oxyalkylene group is an oxyethylene group. ) A polyoxyalkylene derivative and maleic anhydride as essential components, a copolymer obtained by copolymerization in a system having a water content of 1% by weight or less based on the total amount of the polyoxyalkylene derivative and maleic anhydride, 0.1 to 10 kg of an additive comprising the hydrolyzate or a salt of the hydrolyzate,
The present invention provides a concrete composition containing: and a concrete obtained by curing the concrete composition according to (2) (1).

The concrete composition of the present invention is a concrete which does not harden yet, and can be blended in accordance with JIS A 1138 "How to make concrete in a test room", and JIS A 1112 "Washing analysis test method for concrete not yet hardened". It is a property that can be analyzed according to. Examples of the cement used in the present invention include Portland cement, but a composition obtained by mixing Portland cement with blast furnace slag, silica powder, silica fume, etc. can also be used in the present invention. In the composition of the present invention, cement 200-500 k in 1 m ^{3 of} concrete
g is blended. If the amount of cement in 1 m ^{3 of} concrete is less than 200 kg, the strength of the concrete becomes insufficient, which is not preferable. If the amount of cement in 1 m ^{3 of} concrete exceeds 500 kg, the heat generated by the hardening of the cement increases, the drying shrinkage increases, and cracks easily occur, which is not preferable. The fly ash used in the composition of the present invention generally includes fly ash collected from a flue gas or the like of a pulverized coal combustion boiler by a dust collector in a thermal power plant or the like. In the composition of the present invention, 50 to 30 fly ash is added to 1 m ^{3 of} concrete.
0 kg is blended. If the amount of fly ash in 1 m ^{3 of} concrete is less than 50 kg, the significance of blending fly ash is diminished and the workability is reduced, which is not preferable. If the amount of fly ash in 1 m ^{3 of} concrete exceeds 300 kg, the initial strength of the concrete becomes insufficient, which is not preferable. In the composition of the present invention, 100 to 185 kg of water is mixed in 1 m ^{3 of} concrete. If the amount of water in 1 m ^{3 of} concrete is less than 100 kg, it may be difficult to mix the concrete or the flow may decrease, which is not preferable.
When the amount of water in 1 m ^{3 of} concrete exceeds 185 kg,
It is not preferable because the strength of concrete becomes insufficient.
In the present invention, since the amount of water in concrete is particularly important, when the fine aggregate or coarse aggregate to be mixed is not in a surface dry and saturated state, the content amount of water is quantified, and the water actually mixed The amount must be corrected. The fine aggregate used in the present invention passes through a 10 mm mesh sieve defined by JIS A 0203, and a 5 mm mesh sieve has a mass of 85.
% Or more aggregate, and examples of such aggregates include river sand, land sand, mountain sand, sea sand, and crushed sand. In the composition of the present invention, fine aggregate 400 to 1200 k in 1 m ^{3 of} concrete is used.
g is blended. The amount of fine aggregate in 1 m ^{3 of} concrete is 4
If it is less than 00 kg, the coarse aggregate easily separates, and the workability such as transportation, driving, compaction, and finishing is deteriorated, which is not preferable. If the amount of fine aggregate in 1 m ^{3 of} concrete exceeds 1200 kg, workability is impaired again, which is not preferable. The coarse aggregate used in the present invention is an aggregate that stays in a 5 mm net sieve defined by JIS A 0203 in a mass of 85% or more. Such aggregates include river gravel, land gravel, mountain gravel, There are crushed stones. In the composition of the present invention, concrete 1 m ³
400 to 1200 kg of coarse aggregate is mixed therein. If the amount of coarse aggregate in 1 m ^{3 of} concrete is less than 400 kg, the strength of the concrete may decrease, which is not preferable. The amount of coarse aggregate in 1 m ^{3 of} concrete is 1200 kg
If it exceeds, workability is impaired, which is not preferable. In the composition of the present invention, the weights of the fine aggregate and the coarse aggregate are weights in a surface-dried saturated state. It is necessary to select the types and amounts of the fine aggregate and the coarse aggregate to be added to the concrete in consideration of economy, heat generation during hardening, drying shrinkage, and proper balance of aggregate separation and the like.

In the composition of the present invention, a copolymer of the polyoxyalkylene derivative represented by the general formula [1] R ¹ O (AO) _n R ² ... [1] and maleic anhydride, its hydrolyzate or The additive consisting of the salt of the hydrolyzate is 0.1 to 10 in 1 m ^{3 of} concrete.
kg is compounded. In the general formula [1], R ¹ has 2 carbon atoms.
To alkenyl groups such as, for example, vinyl group, allyl group, methallyl group, 3
Examples thereof include -butenyl group, 4-pentenyl group, 3-methyl-3-butenyl group and the like. When the alkenyl group represented by R ¹ has more than 5 carbon atoms, the hydrophilicity of the resulting copolymer becomes insufficient, which is not preferable. In the general formula [1], R ² is a hydrocarbon group having 1 to 8 carbon atoms, and examples of such a hydrocarbon group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group and an isobutyl group. , T-butyl group, amyl group, isoamyl group, hexyl group, heptyl group, octyl group, cyclohexyl group, phenyl group, benzyl group, tolyl group, phenethyl group and the like. When the hydrocarbon group represented by R ² has more than 8 carbon atoms, the compound represented by the general formula [1] has insufficient hydrophilicity, which is not preferable. In the general formula [1], AO is an oxyalkylene group having 2 to 4 carbon atoms, and examples of such an oxyalkylene group include an oxyethylene group, an oxypropylene group,
Examples thereof include an oxybutylene group and an oxytetramethylene group. When the oxyalkylene group represented by AO is an oxymethylene group, the compound represented by the general formula [1] is unstable, and harmful formaldehyde is generated by decomposition, which is not preferable. When the oxyalkylene group represented by AO has more than 4 carbon atoms, the compound represented by the general formula [1] becomes insufficient in hydrophilicity, which is not preferable. In the compound represented by the general formula [1] used in the composition of the present invention, 50 mol% or more of oxyalkylene groups are oxyethylene groups. When the oxyethylene group in the oxyalkylene group is less than 50 mol%, the water solubility of the copolymer with maleic anhydride, its hydrolyzate or a salt of its hydrolyzate becomes insufficient, resulting in performance as a water reducing agent. Is inferior, which is not preferable. General formula [1]
In, the value of n is 10 to 50. When the value of n is less than 10, the setting delay becomes large, and when the value of n exceeds 50, the performance as a water reducing agent is deteriorated, and therefore, both are not preferable. The copolymer of the polyoxyalkylene derivative represented by the general formula [1] and maleic anhydride is obtained by combining the polyoxyalkylene derivative of the general formula [1] and maleic anhydride with a peroxide-based initiator or an azo-based initiator. It can be easily obtained by copolymerizing using an agent or the like by a known method. At that time, a solvent such as benzene, toluene, or xylene can be used. Further, a copolymer obtained by adding another copolymerizable monomer such as styrene or vinyl acetate at the time of copolymerization can also be used in the composition of the present invention. The molar ratio of the copolymerization of the polyoxyalkylene derivative represented by the general formula [1] and maleic anhydride is 3: 7.
It is preferably about 7: 3, particularly about 1: 1.
Upon copolymerization of the polyoxyalkylene derivative represented by the general formula [1] with maleic anhydride, the water content in the system is 1% of the total amount of the polyoxyalkylene derivative and maleic anhydride.
It should be less than or equal to weight%. If the water content in the system is more than 1% by weight of the total amount of the polyoxyalkylene derivative and maleic anhydride, the molecular weight of the copolymer becomes low and the slump loss prevention property is lowered, which is not preferable.

The hydrolyzate of the copolymer of the polyoxyalkylene derivative represented by the general formula [1] and maleic anhydride means that the copolymer reacts with water and the maleic anhydride residue is a maleic acid residue. Is a polymerized product. The salt of the hydrolyzate of the copolymer of the polyoxyalkylene derivative represented by the general formula [1] and maleic anhydride is, for example, an alkali metal obtained by neutralizing with sodium hydroxide, potassium hydroxide or the like. Examples include alkaline earth metal salts obtained by neutralizing with salts, calcium hydroxide, magnesium hydroxide, etc., amine salts obtained by neutralizing with ammonia, monoethanolamine, diethanolamine, triethanolamine, etc. You can In the composition of the present invention, an additive comprising a copolymer of a polyoxyalkylene derivative represented by the general formula [1] and maleic anhydride, a hydrolyzate thereof or a salt of the hydrolyzate is
0.1 to 10 kg, preferably 0.1 per m ^{3 of} concrete.
4 to 5 kg is blended. If the amount of the additive compounded in 1 m ^{3 of} concrete is less than 0.1 kg, a sufficient slump loss preventing effect cannot be obtained, which is not preferable. If the amount of the additive compounded in 1 m ^{3 of} concrete exceeds 10 kg, the effect corresponding to the increase in the compounded amount cannot be improved, which is not preferable. The concrete composition of the present invention, in the range that does not impair the performance of the composition of the present invention, naphthalene sulfonic acid formalin condensate salt, melamine sulfonic acid formaldehyde condensate salt, other additives such as polycarboxylic acid compounds, Alternatively, other antifoaming agents, air entraining agents, rust preventives, setting accelerators, setting retarders and the like can be added. The concrete composition of the present invention can be kneaded using a known mixer such as a batch mixer or a continuous mixer, but a batch mixer can be particularly preferably used. It is desirable to select an appropriate mixer depending on the viscosity of concrete, for example, a drum mixer in the case of soft concrete and a tilting mixer or a forced mixer in the case of hard concrete. The kneaded concrete is poured into the formwork. When driving,
The spout should be as close as possible to the driving surface so that the concrete composition does not separate, and as much lateral flow as possible does not occur after driving. The concrete that has been cast into the formwork is then compacted sufficiently by tamping and vibration. By compaction, the concrete in the formwork is spread to every corner of the formwork and has few voids. The concrete, which has been compacted in the formwork, is cured by subsequent curing. Since the environmental conditions in the early stage of the age following the driving work have a significant effect on the properties of the concrete, the temperature necessary for hydration of the cement is maintained during this period, and the moisture necessary for the hydration reaction is not insufficient. Cure and harden the concrete. It is desirable to protect concrete during the curing period and immediately after that from sunlight, wind and rain, to prevent sudden drying and temperature changes, and to prevent excessive load, harmful vibration, shock, etc. from acting. The hardened concrete of the present invention has various strengths such as compressive strength, excellent creep resistance and fatigue fracture resistance, good weather resistance and corrosion resistance, and has a beautiful appearance. The concrete composition of the present invention can be used in construction such as construction, waterways, dams, tunnels, waterways, and road pavements. Further, the hardened concrete of the present invention is manufactured in a factory and used for building products such as hollow concrete blocks and reinforced concrete assembly tubs, U-shaped reinforced concrete, road products such as rainwater troughs, pipes such as reinforced concrete pipes and core type prestressed concrete pipes. Products, irrigation and drainage products such as reinforced concrete flumes and concrete blocks, reinforced concrete sheet piles, earth retaining products such as pile blocks, revetment products, poles and piles, prestressed concrete bridge girders for slab bridges and bridges, ALC,
It can be a segment of a shield tunnel, a sleeper, a slab track, a cable trough, etc.

[0008]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The slump flow and compressive strength were measured by the following methods. (1) Slump flow In accordance with JIS A 1101, a slump cone is filled with concrete, and then the slump cone is gently lifted vertically and allowed to stand until the concrete stops flowing. After that, the diameter of the concrete spread is measured at two points, which are the maximum value and the direction perpendicular to the maximum value, and the average value is taken as the slump flow value. The symbol (-) in the table is
The slump flow value was so bad that the test was stopped halfway. (2) Compressive strength Measured according to JIS A 1108. Examples 1 to 20 and Comparative Examples 1 to 14 Additives 1 to 8 as component (F) of the present invention shown in Table 1
And using the additives a to d that have been conventionally used,
Tests were conducted by mixing concrete with the mixing compositions shown in Tables, Tables 3 and 4. The composition and test conditions are shown below. Each component was placed in a forced kneading mixer, kneaded for 3 minutes, and then taken out to measure the slump flow. Further, the mixture was transferred to a tilting mixer and mixed at 2 revolutions per minute, and after 30 minutes, 60 minutes and 90 minutes, the slump flow was measured. Also, the compressive strength after 28 days was measured. These results are shown in Tables 2 and 3.
The results are shown in Tables and 4.

[0009]

[Table 1]

[0010]

[Table 2]

[0011]

[Table 3]

[0012]

[Table 4]

[0013]

[Table 5]

[0014]

[Table 6]

From the above results, it can be seen that the concrete composition of the present invention has less slump loss than the concrete compositions of Comparative Examples and has sufficient fluidity and compressive strength.

[0016]

EFFECTS OF THE INVENTION The concrete composition of the present invention provides concrete having excellent fluidity after kneading, little slump loss, and high strength even when a large amount of fly ash is mixed.

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Claims (2)

[Claims] 1. A cement 2 of (A) in 1 m ^{3 of} concrete
00-500kg, (B) Fly ash 50-300k
g, (C) water 100 to 185 kg, (D) fine aggregate 400 to
1200 kg, (E) coarse aggregate 400 to 1200 kg, and
(F) The following general formula [1] R ¹ O (AO) _n R ² ... [1] (wherein R ¹ is an alkenyl group having 2 to 5 carbon atoms, AO is an oxyalkylene group having 2 to 4 carbon atoms, n = 10 to 50,
R ² represents a hydrocarbon group having 1 to 8 carbon atoms. Further, 50 mol% or more of the oxyalkylene group is an oxyethylene group. ) A polyoxyalkylene derivative and maleic anhydride as essential components, a copolymer obtained by copolymerization in a system having a water content of 1% by weight or less based on the total amount of the polyoxyalkylene derivative and maleic anhydride, 0.1 to 10 kg of an additive comprising the hydrolyzate or a salt of the hydrolyzate,
A concrete composition comprising: 2. A concrete obtained by curing the concrete composition according to claim 1.