KR20150022189A - Concrete binder and Process thereof - Google Patents

Abstract

The present invention relates to a concrete binder which can be used by substituting cement, and to a desired manufacturing method thereof. According to the present invention, the concrete binder comprises: one or more particulate materials selected among a hydraulic material, a latent hydraulic material, and a pozzolan material; and calcium magnesium (CaO·MgO) generated by a decarboxylation reaction of CaCO_3·MgCO_3. Also, alkali sulfate can be included in the same. The method for manufacturing the concrete binder sinters CaCO_3·MgCO_3 at 700-1400°C, pyrolyzes carbon dioxide, and manufactures calcium magnesium (CaO·MgO). And then, the concrete binder can be manufactured that all materials are prepared in powder conditions and mixed, or a part or all materials are mixed and ground.

Description

Technical Field [0001] The present invention relates to a concrete binder and a method for manufacturing the same,

The present invention, while the hydraulic to latent hydraulic materials or pozzolanic materials, such as that on the concrete binders and their preferred manufacturing methods that can be used to replace the cement, and more particularly, cement, slag, fly ash as the main material CaCO ₃ · MgCO ₃ The present invention relates to a concrete binder which improves the hardening reactivity of hydraulic or latent hydraulic materials and pozzolanic materials to improve strength, and a method for producing the same.

In the concrete industry, various technologies have been developed to produce concrete by suppressing the use of cement in order to reduce CO ₂ emissions, which is a factor of global warming. Among them, cement is replaced by industrial by-products such as slag and fly ash as a binder.

However, when slag or fly ash is used for concrete, it is known that improvement of workability, reduction of hydration heat, improvement of long-term strength, and improvement of economy are less than that of ordinary portland cement. This initial strength deterioration makes it difficult to actively utilize these industrial byproducts. If the initial strength is low, it is not possible to remove the concrete casting mold early, leading to air delay in the entire construction work.

The representative dolomite of CaCO ₃ · MgCO ₃ is abundant in Korea and is also produced as a by-product in the cement manufacturing process. Such dolomite is mainly used as an abrasive material, an acid soil improving agent, and a refractory material. Dolomite is also used in the concrete field, but it is mostly used as aggregate as in Patent No. 10-0615674.

The present invention has been developed in order to solve the problem of strength reduction when using industrial byproducts such as slag, fly ash and the like as a binder. It also improves the curing reaction of potential hydraulic and pozzolanic materials such as slag, fly ash, A new concrete binder which can be improved and a method for producing the same in a preferable manner.

In order to solve the above-mentioned technical problem, the present invention provides a powder selected from the group consisting of a hydraulic material, a latent hydraulic material, and a pozzolan material; (CaO.MgO) produced by a decarboxylation reaction of CaCO ₃ .MgCO _3. The present invention also provides a concrete binder for replacement of cement. And may further comprise alkali sulfate;

The present invention also relates to a method for producing a concrete binder which comprises calcining CaCO ₃ MgCO ₃ at 700 to 1400 ° C to pyrolyze carbon dioxide to prepare lime cement (CaO · MgO), then preparing all the materials in powder form, Or a mixture of some or all of the materials in the form of bedding, and then pulverizing the mixture to prepare a concrete binder.

According to the present invention, the following effects can be expected.

First, since the present invention forms a binder by mixing lime cement (CaO.MgO) produced by the decarboxylation reaction of CaCO ₃ .MgCO ₃ with a latent hydraulic material or a pozzolan material, The hardening reactivity of the hydraulic or pozzolanic materials is improved and the strength is improved. In particular, when a latent hydraulic material such as slag is used, the reaction of the cement is promoted by the simultaneous use of the same alkali stimulant, which has a negative effect on the fluidity and the securing of the working time. The binder according to the present invention is not limited to the general alkali stimulant, Strength performance can be advantageously improved while minimizing such adverse effects.

Secondly, the present invention can be completed with mixed cement by mixing cement, which is a hydraulic material, with lime gypsum.

Third, the concrete binder according to the present invention is effective in improving the strength of potential hydraulic or pozzolanic materials such as slag, fly ash, and the like, so that the use ratio of the potential hydraulic or pozzolanic materials Can be increased. As a result, it is possible to reduce the amount of cement used instead of using industrial byproducts such as slag, fly ash, etc., thereby securing economical efficiency and improving environmental problems caused by cement production.

Fourth, since the concrete binder according to the present invention is particularly effective in improving the initial strength, the concrete strength of the concrete member can be secured early when applied to construction work, leading to air savings.

The present invention relates to a cementitious concrete composition comprising caustic soda (CaO.MgO), which is a decarbonated product of CaCO ₃ .MgCO ₃ , and CaO · MgO ₃ as a main ingredient while using a hydraulic material such as cement or a latent hydraulic material such as slag or a ply ash material such as fly ash To a binder. Specifically, the concrete binder according to the present invention is a powder selected from at least one of a hydraulic material, a latent hydraulic material, and a pozzolan material; (CaO.MgO) produced by decarboxylation of CaCO ₃ .MgCO ₃ . In the present invention, the concrete binder may be used in place of cement as well as cement in all cases where cement is used as a binder, and may be applied to mortars, pastes, and the like.

In the present invention, the powder includes a hydraulic material such as cement and the like, which is hardened by curing by direct reaction with water, a latent hydraulic material such as blast furnace slag, steel slag, electric furnace slag, a pozzolan material such as fly ash and kaolin material, One or two or more species may be selected from hydraulic materials and pozzolanic materials.

In the present invention, lime gut (CaO.MgO) is dissolved in the compounding water when the present invention is used as a binding material to generate OH-ions and raise the pH. As a result, the reactivity of the hydraulic or latent hydraulic material and the pozzolanic material . Lime Goto is the CaCO ₃ · MgCO ₃ The product generated by reaction decarboxylation, where CaCO ₃ · MgCO ₃ is a CaCO ₃ or MgCO ₃ 90% or in particular is a MgCO ₃ content is less than 5% lime material, for example MgCO ₃ , limestone, dolomite and the like. In particular, dolomite is produced in the cement manufacturing process as well as being buried in a large quantity in the domestic market, so that it can lead to cost reduction by actively using dolomite. CaCO ₃ · MgCO ₃ is calcined at a high temperature of 700 to 1400 ° C. to decompose carbon dioxide and decarboxylate to obtain lime gypsum (CaO · MgO).

Lime gypsum (CaO · MgO) is dissolved in the formulation water as shown in the following formula (1, 2, 3) to produce OH - ions and raise the pH. Particularly, the addition of MgO contributes to controlling the reaction rate and increasing the strength. In other words, CaO reacts directly with water and it is difficult to obtain proper working time. On the other hand, since MgO reacts more slowly than CaO to cement material, it can be controlled by reaction rate of MgO to the reaction of cement material, of Mg ^{+ 2} ions can contribute to the Ca ^{2 +} smaller cement hydrate, so that can be filled in the gap size to be more chambers, the cement hydrates strength.

MgO, CaO + 2H ₂ O - > Ca (OH) ₂ + Mg (OH) ₂

(Equation _{2) Ca (OH) 2 -} > Ca 2 + + 2OH ^-

(Formula 3) Mg (OH) ₂ -> Mg ^{2 +} + 2OH ^-

If less than 0.03 parts by weight of the calcined gypsum is added to 100 parts by weight of the powder, the strength enhancement is insufficient because it does not contribute to the improvement of reactivity. If the amount of the calcined gypsum is more than 5 parts by weight, the fluidity is decreased due to excessive reaction activation, It is easy to shorten.

Further, the concrete binder according to the present invention may further include alkali sulfate. Alkali sulphate dissolves in the compound water to generate OH - ions and raise the pH, while sulfate (SO ₄ ^{2 -} ) ions react with C ₃ A of cement to contribute to the formation of etringium, . Alkali sulfates include M ₂ SO ₄ (Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO _4, etc.), MeSO ₄ (CaSO ₄ , MgSO ₄ Etc.), such as Na ₂ SO ₄ (4 and 5).

(Formula 4) Na ₂ SO ₄ + H ₂ O-> 2Na ⁺ + SO ₃ ^{2 -} + 2OH ^-

(Equation _{5) 3CaO · Al 2 O 3} + 3CaSO 4 · 2H 2 O + 26H 2 O -> 3CaO · Al 2 O 3 · 3CaSO 4 · 32H 2 O

The amount of alkali sulfate is preferably 0.03 to 5 parts by weight per 100 parts by weight of the powder. When the amount of the alkali sulfate is less than 0.03 parts by weight, the strength improvement is insufficient because it does not contribute to the improvement of reactivity. If the amount is more than 5 parts by weight, It is easy to shorten and the economy is poor.

Meanwhile, the concrete binder according to the present invention can be manufactured by simply preparing all materials in powder form and then mixing them (dry mixing). That is, powder, lime gutta, and alkali sulfate are prepared in powder form and simply mixed. It is also possible to produce a mixture by mixing some or all of the materials in the form of a bed and pulverizing the mixture. At least one of powder, lime gutta, and alkali sulphate is mixed in a suppository state and then pulverized (mixed pulverization). In this case, in order to improve the grinding efficiency, the grinding aid may be added, mixed and pulverized, or the dispersant may be added and mixed in order to improve the fluidity through effective dispersion of the material. In particular, when slag of a bed form is utilized, it is possible to reduce the manufacturing cost when the slag is mixed and pulverized. In the mixed pulverization method, various pulverizers used in the inorganic material industry such as a ball mill, a raymond mill, and a vibrating mill can be used as the pulverizer, and it is preferable that the pulverizer after the production is 3500 to 4500 (cm2 / g).

The concrete binder prepared as described above is a kind of mixed cement if it is applied with cement as powder, and it is a kind of admixture if it contains slag, fly ash and kaolin except powdered cement. Such mixed cement and admixture may be mixed with ordinary cement (mortar, paste, etc.) in place of cement.

Hereinafter, the present invention will be described in detail based on experimental examples. However, the following experimental examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

[Experimental Example] Properties of Concrete According to Types of Binder

1. Manufacture of Concrete Binder

The concrete binder was prepared as shown in [Table 1]. The lime gauze and alkali sulphate used in the production of concrete binder are shown in [Table 2 and 3].

Composition (parts by weight) of concrete binder and manufacturing method division Powder Lime goto alkali
Sulfate Manufacturing method DB1 Blast furnace slag fine powder (BS) MgO · CaO - Each material was weighed and mixed with a dry mixer 100 2 - DB2 Blast furnace slag fine powder (BS) MgO · CaO Na ₂ SO ₄ 100 2 One DBF1 Blast furnace slag fine powder (BS) + fly ash (FA) at a weight ratio of 5: 1 MgO · CaO - 100 2 - DBF2 Blast furnace slag fine powder (BS) + fly ash (FA) at a weight ratio of 5: 1 MgO · CaO Na ₂ SO ₄ 100 2 One MB1 Blast furnace slag MgO · CaO - Each material was weighed and pulverized by a pulverizer 100 2 - MB2 Blast furnace slag MgO · CaO Na ₂ SO ₄ 100 2 One

Characteristics of lime goto Chemical Composition (%) Density
(g / cm3) Blaine
Specific Area (cm2 / g) CaO MgO SiO2 Al2O3 Ig.loss 52.8 32.2 0.89 0.32 1.85 3.12 3,038

Characteristics of alkali sulfate Na2SO4 content Insoluble matter moisture > 99% &Lt; 0.05% <0.2%

2. Concrete formulation

The concrete was mixed with the composition shown in Table 4 below. In the concrete formulations, binder materials and aggregates were used as shown in the following [Table 4 and 5]. Polycarboxylic acid-based admixtures with a specific gravity of 1.11 and a solid content of 23% were used as the admixture. And the concrete was mixed with various combinations of binders as shown in Table 7 below.

Concrete formulations Compounding strength W / C
(%) S / a
(%) Unit material amount (kg / ㎥) Mixed water Binders Fine aggregate Coarse aggregate Admixture 27 MPa 48.5 46.9 182 375 776 886 2.63

Binder properties division cement Fine powder of blast furnace slag Fly ash Density (g /) 3.15 2.90 2.22 Powder (cm &lt; 2 &gt; / g) 3419 4272 3519

Aggregate property division Mab Rate (F.M) Density (g / l) Absorption Rate (%) Fine aggregate 2.82 2.59 0.78 Coarse aggregate 6.81 2.61 0.68

division Composition ratio of binder (wt%) OPC BS FA DB1 DB2 MB1 MB2 DBF1 DBF2 Sum Comparative Example 1 55 45 - - - - - - - 100 Comparative Example 2 40 60 - - - - - - - 100 Example 1 40 - - 60 - - - - - 100 Example 2 40 - - - 60 - - - - 100 Example 3 40 - - - - 60 - - - 100 Example 4 40 - - - - - 60 - - 100 Comparative Example 3 50 40 10 - - - - - - 100 Comparative Example 4 40 50 10 - - - - - - 100 Example 5 40 - - - - - - 60 - 100 Example 6 40 - - - - - - - 60 100 Example 7 40 - 10 - - 50 - - - 100 Example 8 40 - 10 - - - 50 - - 100

3. Concrete characteristics

The slump, the amount of air, and the compressive strength of the concrete thus prepared were measured. Concrete tests were carried out using slump (KS F 2402, slump test method of concrete) and air quantity (KS F 2421, method of air volume test of unconfined concrete by pressure method) immediately after the concrete was manufactured using a forced mixer, Was measured, and after 60 minutes, it was measured again to confirm the change. After that, a specimen for compressive strength test of Ø100 × 200mm was prepared and the compressive strength (KS F 2403, method of specimen for strength test of concrete) was measured according to the ages. The results of the above tests are shown in Table 8 below.

Concrete characteristics division Air volume (%) Slump (mm) Compressive strength (MPa) Early 60 minutes Early 60 minutes 3 days 7 days 28th Comparative Example 1 5.8 4.7 180 155 14.3 23.6 30.3 Comparative Example 2 6.2 5.2 190 165 11.3 20.2 28.1 Example 1 5.9 5.1 195 165 14.6 24.1 31.3 Example 2 6.2 5.3 185 155 15.2 24.6 30.8 Example 3 6.4 5.3 190 165 13.6 25.6 35.0 Example 4 5.8 5.1 180 160 14.8 26.0 33.3 Comparative Example 3 4.8 3.9 190 175 13.8 21.9 28.5 Comparative Example 4 5.2 4.1 195 175 10.4 19.8 26.3 Example 5 5.3 3.9 200 180 13.4 22.5 29.3 Example 6 4.8 3.8 195 170 13.6 23.1 28.7 Example 7 4.8 3.7 195 165 12.8 22.8 30.8 Example 8 4.9 4.1 190 160 13.7 24.1 32.4

In Comparative Examples 1 and 2 and Examples 1 to 4, cement and blast furnace slag were used as binders. As shown in Table 8, the air amount and slump were not significantly different between the comparative example and the example do. Comparing Examples 1 to 4 and Comparative Example 2 in which the amounts of cement are the same, Examples 1 to 4 are superior to those of Comparative Example 2 in terms of strength strength up to 28 days strength as well as initial strength. Further, Is similar to that of Comparative Example 1 in which cement is used in a large amount, and the strength at 28 days is rather superior.

In Comparative Examples 3 to 4 and Examples 5 to 8, cement, blast furnace slag fine powder and fly ash were used as binders. In this case, however, the air amount and slump were not significantly different between the comparative example and the example. In Examples 5 to 8, compared with Comparative Example 4 in which the amount of cement and fly ash used was the same, the initial strength was superior to that in Comparative Example 3 in which cement was used in a large amount, The strength on the 28th day is rather rather superior.

According to the above results, the concrete binder according to the present invention can be advantageously used with excellent strength development.

Claims (9)

A powder selected from at least one of a hydraulic material, a latent hydraulic material, and a pozzolana material;
Limestone (CaO · MgO) produced by the decarboxylation of CaCO ₃ · MgCO ₃ ;
And a reinforcing member for reinforcing the concrete. The method of claim 1,
Wherein the composition is composed of 0.03 to 5 parts by weight of the lime cement in 100 parts by weight of the powder. The method of claim 1,
Alkali sulfates;
Further comprising a plurality of brittle joints. 3. The method of claim 2,
Wherein the alkali sulfate is contained in an amount of 0.03 to 5 parts by weight based on 100 parts by weight of the powder. The method according to claim 3 or 4,
The alkali sulfate may be,
At least one of Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , CaSO ₄ and MgSO ₄ is selected. 5. The method according to any one of claims 1 to 4,
The powder,
Portland cement, blast furnace slag, steel making slag, electric furnace slag, fly ash, and kaolin materials. A method for manufacturing a concrete binder according to any one of claims 1 to 4,
CaCO ₃ MgCO ₃ is fired at 700 to 1400 ° C to pyrolyze carbon dioxide to produce lime gutta (CaO.MgO)
Wherein all the materials are prepared in powder form and then mixed to produce a concrete binder. A method for manufacturing a concrete binder according to any one of claims 1 to 4,
CaCO ₃ MgCO ₃ is fired at 700 to 1400 ° C to pyrolyze carbon dioxide to produce lime gutta (CaO.MgO)
A method for producing a concrete binder material, comprising the steps of: mixing a part or all of the materials in a state of bedding and pulverizing the mixture; 9. The method of claim 8,
A pulverizing additive, and a dispersing agent, and then pulverizing the resulting mixture.