KR101701673B1 - Binder compositions for concrete, concrete compositions comprising the same, and concrete structure manufactured by the same - Google Patents

Abstract

The present invention relates to a binder composition for concrete having excellent freezing and thawing resistance, a concrete composition comprising the same, and a concrete structure produced using the same. The binder composition for concrete comprises: cement; an amorphous pozzolan material; and a crystalline pozzolan material including melilite and beta-dicalcium silicate.

Description

Technical Field [0001] The present invention relates to a binder composition for concrete, a concrete composition containing the same, and a concrete structure produced using the same. BACKGROUND OF THE INVENTION [0002]

The present invention provides a binder composition for concrete, a concrete composition containing the same, and a concrete structure manufactured using the same. Specifically, a concrete structure having excellent resistance to freezing and thawing is provided by using a binder composition for concrete containing a crystalline pozzolanic material.

Concrete is one of the most widely used and indispensable building materials that combines durability and economy. Concrete was originally made of volcanic ash and limestone in Roman times, but it was the first time that concrete was reinforced with wire mesh in France in 1867 after Portland Cement was invented in the early 19th century. Since then, the development of concrete has been continuing mainly in Germany and has become a center of construction materials for civil engineering and construction.

Conventional concrete pavement has a problem of air pollution due to the generation of CO ₂ gas and soil pollution and water pollution problem due to the dissolution of toxic substances due to the use of a large amount of cement when concrete is mixed.

Also, even if a large amount of cement is used, the existing concrete pavement is not resistant to freezing and thawing. Therefore, pearl and line eye deterioration of concrete pavement will occur when the winter passes through the region below the winter Lt; / RTI > Therefore, there is a problem that the performance of the concrete road is deteriorated and the maintenance cost is continuously generated.

Korea Open Publication: KR 2011-0119887 A

It is an object of the present invention to provide a binder composition for concrete which has a reduced cement content to reduce environmental pollution problems and has excellent resistance to freezing and thawing, a concrete composition containing the same, and a concrete structure manufactured using the same .

One embodiment of the present disclosure relates to a cement; Amorphous pozzolanic materials; And a crystalline pozzolanic material.

An embodiment of the present invention is a concrete composition for a concrete comprising 20 wt% or more and 40 wt% or less; Not less than 20% by weight and not more than 40% by weight of fine aggregate; And from 30% by weight to 60% by weight of coarse aggregate; And from 5 to 15% by weight of water.

One embodiment of the present disclosure provides a concrete structure produced using the concrete composition.

The concrete composition containing the binder composition for concrete according to one embodiment of the present invention is advantageous in that the cement content is low and the environmental pollution caused by the cement of the concrete structure manufactured using the composition is reduced.

The binder composition for concrete according to one embodiment of the present invention has the advantage of reducing environmental burden by increasing utilization of industrial waste by using a crystalline pozzolanic material which is discharged as industrial waste.

The concrete structure manufactured by using the binder composition for concrete according to one embodiment of the present invention is highly resistant to freezing and thawing and has an advantage of reducing the maintenance cost of the concrete structure.

Fig. 1 shows the result of executing a freeze-thaw resistance test of a concrete structure according to Examples and Comparative Examples.

Whenever a component is referred to as "comprising ", it is to be understood that the component may include other components as well, without departing from the scope of the present invention.

Cement is the main component for curing concrete. It exhibits strength through hydration and plays a major role in hydration heat during the reaction. However, since cement is an inorganic material that generates a large amount of carbon dioxide gas during production and causes toxic substances to be discharged, causing soil pollution and water pollution, efforts should be made to reduce the cement content in the manufacture of concrete structures.

The present inventors have developed a binder composition for concrete according to the present invention using a crystalline pozzolanic material, and the concrete composition and the concrete structure containing the same have a great effect on compression and tensile strength of the concrete structure while lowering the content of cement And further has excellent freeze-thaw resistance resistance.

Hereinafter, the present invention will be described in more detail.

One embodiment of the present disclosure relates to a cement; Amorphous pozzolanic materials; And a crystalline pozzolanic material.

According to one embodiment of the present disclosure, the cement may be any one or more of the portland 1 to 5 cement specified in KS.

According to one embodiment of the present invention, the cement content may be 60 wt% or more and 80 wt% or less based on 100 wt% of the binder composition for concrete. Specifically, the content of the cement may be 65 wt% or more and 75 wt% or less based on 100 wt% of the binder composition for concrete.

When the content of the cement is within the above range, the strength of the concrete structure can be minimized, and the amount of the binder composition for concrete can be 20 wt% to 40 wt%, or 25 wt% to 35 wt% It is possible to reduce the amount of cement used. Accordingly, when the binder composition for concrete according to the present invention is used, it can exhibit long-term strength and durability that is equal to or higher than that of existing concrete structures and can be manufactured in a more environmentally friendly manner.

According to one embodiment of the present disclosure, the major components of the amorphous pozzolanic material are SiO ₂ , Al ₂ O ₃ , CaO and MgO, accounting for from 94% to 97% of the total composition.

According to one embodiment of the present invention, the amorphous pozzolanic material can be produced by subjecting the molten slag separated by the difference in specific gravity in the blast furnace to quenching with cold air or cold water when producing pig iron in a steelworks. The amorphous pozzolanic material may be a natural pozzolan such as volcanic ash, tuff, diatomaceous earth, an artificial pozzolan such as silica fume, silica gel, and fly ash.

According to one embodiment of the present disclosure, the crystalline pozzolanic material is crystalline, which is a chemically stable structure, and has little hydraulicity. The main component of the crystalline pozzolanic material is gel Day _{(2CaO · Al 2 O 3 ·} SiO 2) with O germanium nitro (2CaO · MgO · 2SiO ₂₎ employ melril light chain (Melilite) and β- die calcium silicate (the β- can be 2CaO · SiO _2). Silicate and small amounts of sulfur components such as anorthite (CaO.Al ₂ O ₃ .SiO ₂ ), melite (3CaO.MgO. 2SiO ₂ ) and the like may be present in the crystalline matrix.

Since the crystalline pozzolanic material is substantially free of F-CaO and F-MgO, a special treatment may be dispensed with in order to distinguish it from other slag in terms of durability. In addition, the crystalline pozzolanic material may have a higher soluble sulfur content than the amorphous pozzolanic material, especially a higher proportion of S ₂ O ₃ ^2- than the amorphous pozzolanic material. The sulfur content of the crystalline pozzolanic materials may be present as a calcium sulfide crystalline, which on contact with water Ca ^{2 +} and negative ions S ^₂ O _{3 2} ^- is dissociated by elution, S ^₂ O _{3 2} ^- ions is C ₃ A (3CaO · Al ₂ O ₃ : Tricalcium aluminate aluminate), it is possible to improve the initial fluidity and maintain fluidity in the production of concrete structure.

According to one embodiment of the present disclosure, the crystalline pozzolanic material can be obtained from slowly chilled industrial wastes when molten slag separated by the difference in specific gravity in the blast furnace when producing pig iron in a steel mill. Therefore, the binder composition for concrete according to one embodiment of the present invention can reduce the environmental burden by increasing the utilization of the industrial waste by using the crystalline pozzolanic material that is discharged as industrial waste.

According to one embodiment of the present invention, the content of the crystalline pozzolanic material may be 5 wt% or more and 40 wt% or less based on 100 wt% of the binder composition for concrete. Specifically, the content of the crystalline pozzolanic material may be 10 wt% or more and 30 wt% or less based on 100 wt% of the binder composition for concrete.

When the content of the crystalline pozzolanic material is within the above range, the resistance to freezing and thawing of the concrete structure can be greatly improved as compared with the case where the crystalline pozzolanic material is not used. If the content of the crystalline pozzolanic material is within the above range, the compressive strength and tensile strength of the concrete structure may not be significantly affected.

The crystalline pozzolanic material and the amorphous pozzolanic material have different physical properties due to different phases of the material due to the difference in cooling method during their formation. For example, the grinding ability of the crystalline pozzolanic material and the amorphous pozzolanic material produced in the electric furnace was evaluated to be about 2.7 times better than that of amorphous crystalline material. This is because, in the case of the crystalline pozzolanic material, since a large amount of gas is generated due to the slow cooling effect generated at the time of generation, the crystalline pozzolanic material has a porous crystalline form in a massive state different from the amorphous pozzolanic material, and has a different physical property from the amorphous pozzolanic material do.

According to one embodiment of the present disclosure, the weight ratio of the amorphous pozzolanic material to the crystalline pozzolanic material may be from 10: 1 to 1: 1. In particular, the weight ratio of the amorphous pozzolanic material to the crystalline pozzolanic material may be from 7: 1 to 3: 1.

An embodiment of the present invention is a concrete composition for a concrete comprising 10 wt% or more and 30 wt% or less; Not less than 20% by weight and not more than 40% by weight of fine aggregate; And from 30% by weight to 60% by weight of coarse aggregate; And from 5 to 20% by weight of water.

According to one embodiment of the present invention, the content of the binder composition for concrete may be 10 wt% or more and 20 wt% or less based on 100 wt% of the concrete composition.

According to one embodiment of the present invention, the content of the fine aggregate may be 25 wt% or more and 35 wt% or less based on 100 wt% of the concrete composition.

According to one embodiment of the present invention, the content of the coarse aggregate may be 45 wt% or more and 55 wt% or less based on 100 wt% of the concrete composition.

According to one embodiment of the present invention, the water content may be 5 wt% or more and 10 wt% or less based on 100 wt% of the concrete composition.

The fine aggregate may be an aggregate having a particle diameter of 0.01 mm to 5 mm, and the coarse aggregate may be an aggregate having a particle diameter of 5 mm to 100 mm. The aggregates may be mixed with different particle sizes. In particular, the coarse aggregate may be used alone, or may be mixed with 19 mm or 25 mm aggregate.

According to an embodiment of the present invention, the binder composition for concrete may further include at least one admixture selected from the group consisting of a water reducing agent, an air entraining agent, gypsum, lime, and fly ash.

According to one embodiment of the present invention, the water reducing agent may include one or more selected from the group consisting of ligninsulfonate, polynaphthalenesulfonate, polycarboxylic acid, polymelamine sulfonate and polycarboxylate .

The amount of the water reducing agent may be 0 wt% or more and 5 wt% or less based on 100 wt% of the binder composition for concrete. Specifically, the content of the water reducing agent may be 0.1 wt% or more and 5 wt% or less, or 0.1 wt% or more and 2 wt% or less based on 100 wt% of the binder composition for concrete.

When the content of the water reducing agent is within the above range, the fluidity of the binder composition for concrete can be increased to ensure workability, and it is possible to contribute to improvement of proper dispersibility without interfering with the generation of bubbles.

According to one embodiment of the present invention, the air entraining agent can consistently contain air bubbles in concrete using an air entraining agent. The air entraining agent has an anionic surfactant as a main component, and it is easy to control the amount of air and is economical, and durability against freezing and thawing when used in concrete can be increased.

The content of the air entraining agent may be 0 wt% or more and 3 wt% or less based on 100 wt% of the binder composition for concrete. Specifically, the content of the air entraining agent may be 0.1 wt% or more and 3 wt% or less, or 0.1 wt% or more and 2 wt% or less based on 100 wt% of the binder composition for concrete.

When the content of the air entraining agent is within the above range, uniform air bubbles can be distributed without deteriorating the mechanical performance of the concrete structure, so that the performance of the concrete structure can be made uniform. Further, .

The gypsum can be obtained by synthesizing flue gas desulfurization, which is generated as a byproduct or an industrial by-product, from a water gypsum or phosphate gypsum by a pressurized water vapor method or a pressurized hydrothermal method at a temperature of 100 ° C to 150 ° C.

The gypsum can exhibit excellent shrinkage resistance and excellent initial strength development and stable long-term strength maintenance performance as compared with a general cement composition without material separation, bleeding and plastic shrinkage, Not only can it be controlled but also it can play a role of improving the workability in the section having irregular shape by securing high initial fluidity. In addition, unlike conventional cement compositions, there is no fear of neutralization since the degree of alkalinity is not high, and there is an advantage that stable durability can be ensured from the dry and wet repetitive action and the freezing and thawing action by securing a certain level of endurance pore.

The lime is a product manufactured by calcining limestone according to the characteristics of the product to be produced, and the main component may be calcium oxide (CaO). The limestone may be prepared by calcining limestone according to the conditions of a calcining furnace (fluid furnace) and heating the calcined limestone at about 900 ° C to 1,100 ° C for a certain period of time. The calcined limestone may have a CaO content of 90% or more and a grain size of 100 mesh or more .

Since the lime expands rapidly upon reaction with water and dissipates heat, the use of a certain amount of lime can be expected to promote hydration, enhance long-term strength, and improve fire resistance.

According to one embodiment of the present invention, the content of the gypsum and / or lime is 1 wt% to 15 wt%, 1 wt% to 10 wt%, or 1 wt% to 5 wt% based on 100 wt% Or less.

One embodiment of the present disclosure provides a concrete structure produced using the concrete composition.

The concrete structure may be manufactured by using concrete such as concrete road, small river masonry, retaining wall, and concrete block.

The concrete structure may be manufactured by the following method of manufacturing a concrete structure.

Specifically, the method comprises the steps of charging the concrete binder composition and the aggregate, mixing the charged materials, mixing the charged material, mixing the water after the dry beaming step to produce concrete mortar, and injecting the concrete mortar into the mold And then curing the concrete structure.

The step of injecting the concrete binder composition and the aggregate is a step of injecting the concrete binder composition, the coarse aggregate and the fine aggregate.

The key beaming step is a step of mixing the aggregate material and the binder material, in which water is not supplied. Therefore, it is easy to confirm the mixing state of the material by mixing the aggregate and the binder before water is introduced. At this time, a rotary mixer is used, and mixing can be performed at a speed of 25 rpm to 35 rpm to evenly mix the aggregate and the cement. Specifically, mixing may be performed for 1 minute and 30 seconds to 2 minutes, but the mixing time is not limited thereto. After mixing for a predetermined time, it is checked whether or not the materials are mixed, the rotation speed is maintained at 15 rpm to 25 rpm, You may.

The step of preparing the concrete mortar is a step of mixing water and optionally an admixture into the aggregate and binder in a state where the non-beam step is completed. At this time, the rotational speed of the rotary mixer can be maintained at a rotational speed of 15 rpm to 25 rpm. In addition, water may be added to the total amount of the required amount, and the admixture may be partially mixed with a part of the amount of the admixture, and then the remaining admixture may be further added to further mix.

The concrete curing method can be applied to the curing step. Specifically, the curing step may be to cover the curing cloth after curing agent is cured.

Hereinafter, the present invention will be described in detail by way of examples with reference to the drawings. However, the embodiments according to the present disclosure can be modified in various other forms, and the scope of the present specification is not construed as being limited to the embodiments described below. Embodiments of the present disclosure are provided to more fully describe the present disclosure to those of ordinary skill in the art.

[ Comparative Example  One]

A binder composition for concrete was prepared with 100 wt% of cement, and a fine aggregate having a particle size of 0.01 mm to 5 mm and a coarse aggregate having a maximum particle size of 32 mm were mixed. Furthermore, a polycarboxylic acid based water reducing agent and an anionic surfactant-based air entraining agent were further added as an admixture, water was added thereto to prepare a concrete composition, and a concrete structure was prepared using the same.

At this time, the content of the fine aggregate was 27 wt% with respect to the concrete composition, the content of the coarse aggregate was 51 wt% with respect to the concrete composition, the content of the water reducing agent with respect to the concrete composition was 0.5 wt% The content of the air entraining agent was 0.2 wt% with respect to the concrete composition, and the content of water was 7 wt% with respect to the concrete composition.

[ Comparative Example  2]

80% by weight of cement and 20% by weight of amorphous pozzolan (fly ash) were mixed to prepare a binder composition for concrete, and a fine aggregate having a particle size of 0.01 mm to 5 mm and a coarse aggregate having a maximum particle size of 32 mm were mixed. Furthermore, a polycarboxylic acid based water reducing agent and an anionic surfactant-based air entraining agent were further added as an admixture, water was added thereto to prepare a concrete composition, and a concrete structure was prepared using the same.

At this time, the content of the fine aggregate was 27 wt% with respect to the concrete composition, the content of the coarse aggregate was 51 wt% with respect to the concrete composition, the content of the water reducing agent with respect to the concrete composition was 0.5 wt% The content of the air entraining agent was 0.2 wt% with respect to the concrete composition, and the content of water was 7 wt% with respect to the concrete composition.

[ Comparative Example  3]

60% by weight of cement and 40% by weight of amorphous pozzolan were mixed to prepare a binder composition for concrete, and a fine aggregate having a particle size of 0.01 mm to 5 mm and a coarse aggregate having a maximum particle size of 32 mm were mixed. Furthermore, a polycarboxylic acid based water reducing agent and an anionic surfactant-based air entraining agent were further added as an admixture, water was added thereto to prepare a concrete composition, and a concrete structure was prepared using the same.

At this time, the content of the fine aggregate was 27 wt% with respect to the concrete composition, the content of the coarse aggregate was 51 wt% with respect to the concrete composition, the content of the water reducing agent with respect to the concrete composition was 0.5 wt% The content of the air entraining agent was 0.2 wt% with respect to the concrete composition, and the content of water was 7 wt% with respect to the concrete composition.

[ Example  One]

35% by weight of cement 60% by weight of amorphous pozzolan and 5% by weight of crystalline pozzolan were mixed to prepare a binder composition for concrete, and a fine aggregate having a particle size of 0.01 mm to 5 mm and a coarse aggregate having a maximum particle size of 32 mm were mixed. Furthermore, a polycarboxylic acid based water reducing agent and an anionic surfactant-based air entraining agent were further added as an admixture, water was added thereto to prepare a concrete composition, and a concrete structure was prepared using the same.

At this time, the content of the fine aggregate was 27 wt% with respect to the concrete composition, the content of the coarse aggregate was 51 wt% with respect to the concrete composition, the content of the water reducing agent with respect to the concrete composition was 0.5 wt% The content of the air entraining agent was 0.2 wt% with respect to the concrete composition, and the content of water was 7 wt% with respect to the concrete composition.

[ Example  2]

30% by weight of cement 60% by weight of amorphous pozzolan and 10% by weight of crystalline pozzolan were mixed to prepare a binder composition for concrete, and a fine aggregate having a particle size of 0.01 mm to 5 mm and a coarse aggregate having a maximum particle size of 32 mm were mixed. Furthermore, a polycarboxylic acid based water reducing agent and an anionic surfactant-based air entraining agent were further added as an admixture, water was added thereto to prepare a concrete composition, and a concrete structure was prepared using the same.

At this time, the content of the fine aggregate was 27 wt% with respect to the concrete composition, the content of the coarse aggregate was 51 wt% with respect to the concrete composition, the content of the water reducing agent with respect to the concrete composition was 0.5 wt% The content of the air entraining agent was 0.2 wt% with respect to the concrete composition, and the content of water was 7 wt% with respect to the concrete composition.

The amorphous pozzolans in Comparative Example 3, Example 1 and Example 2 were made of pozzolan material produced in an electric furnace.

In the crystalline pozzolans of Examples 1 and 2, the massive material was firstly pulverized to remove the iron contained therein, and the pulverized material was subjected to secondary pulverization with a size of 1 to 2 cm using a jaw crusher, Cross bit), and then powder was pulverized and a crystalline pozzolana powder was obtained by using a ball mill.

Specific details according to the above Comparative Examples and Examples are shown in Table 1 below.

Coarse aggregate maximum particle diameter
(Mm) Water-binder ratio
(%) Fine aggregate rate
(%) Unit volume weight (kg / m3) Admixture
(%) water Binders Fine aggregate thick
aggregate cement Amorphous
Pozzolan Crystalline
Pozzolan Comparative Example 1 32 45 36 157 350 645 1194 0.7 Comparative Example 2 280 70 626 1160 Comparative Example 3 210 140 632 1171 Example 1 210 123 17 632 1171 Example 2 210 105 35 632 1171

In Table 1, the fine aggregate ratio means a ratio of the fine aggregate to the total volume occupied by the aggregate in the concrete.

Furthermore, the results of evaluating the setting time, compressive strength and hip strength of the concrete structure produced according to the above Comparative Examples and Examples are shown in Table 2 below.

The results of the freeze-thaw resistance test of the concrete structures prepared according to the above Comparative Examples and Examples are shown in FIG.

division Setting time
(min) Flexural strength
(MPa) Compressive strength
(MPa) Slump
(mm) Air volume
(%) Fresh closing 28th 56 days 28th 56 days Comparative Example 1 165 280 4.5 6.9 35 37 48 4.5 Comparative Example 2 207 251 6.0 7.9 24 28 70 6.7 Comparative Example 3 203 306 7.9 8.2 37 38 70 4.5 Example 1 200 303 7.7 8.7 35 38 70 5.0 Example 2 210 259 6.2 6.8 32 32 75 6.9

 Condensation time: KS F 2436 (Test method for concrete condensation time by penetration resistance)

 Compressive strength: KS F 2422 (Compressive strength test method of concrete)

 Flexural Strength: KS F 2408 (Test Method for Flexural Strength of Concrete)

 Freeze-thaw resistance: KS F 2456 (A type, rapid freeze-thaw test in water)

 Condensation test: KS F 2436 (Test method for concrete condensation time by penetration resistance)

 Air mass test: KS F 2421 (Concrete air mass experiment)

According to the above Table 2, the concrete structure according to the embodiment shows the results of satisfying the air-flow amount and flowability regulation of the road pavement concrete (road construction specification), and the condensation is terminated within 8 hours suitable for the concrete pavement composition of the road It is confirmed that there is no problem in using as concrete for road pavement.

Further, comparing the strength characteristics of concrete using crystalline pozzolanic material, it can be confirmed that the substitution of amorphous pozzolanic material does not greatly affect the compression and tensile strength of concrete.

Also, according to FIG. 1, Example 1, which was substituted for amorphous pozzolan by 5% by weight of the crystalline pozzolanic material, exhibited stable freeze-thaw resistance and was above the levels of Comparative Examples 1 and 3. Furthermore, Example 2, in which amorphous pozzolan was substituted for 10% by weight of the crystalline pozzolanic material, showed significantly better freeze-thaw resistance for Comparative Examples 1 to 3.

As can be seen from the above results, when the amorphous pozzolan contained in the binder composition for concrete is partly replaced with a crystalline pozzolan, it is possible to reduce the waste treatment cost, reduce the burden on the environment by using the crystalline pozzolan discarded as industrial waste, It can be seen that the freeze-thaw resistance also increases.

Compared with the case where the binder composition for concrete is used in an amount of 100% by weight of cement as in Comparative Example 1, Examples 1 and 2 can improve the resistance to freezing and thawing without loss of physical strength, It is possible to reduce the pollution of the environment.

Claims (7)

cement; Amorphous pozzolanic materials; And a crystalline pozzolanic material comprising melilite and beta -dicalcium silicate,
The content of the crystalline pozzolanic material is 5 wt% or more and 40 wt% or less based on 100 wt% of the binder composition for concrete,
Wherein the weight ratio of the amorphous pozzolanic material to the crystalline pozzolan material is from 10: 1 to 1: 1. delete delete The method according to claim 1,
Wherein the content of the cement is 60 wt% or more and 80 wt% or less based on 100 wt% of the binder composition for concrete. At least 10 wt% and not more than 30 wt% of the binder composition for concrete according to claim 1; Not less than 20% by weight and not more than 40% by weight of fine aggregate; And from 30% by weight to 60% by weight of coarse aggregate; And from 5% to 20% by weight of water. The method of claim 5,
Wherein the concrete composition further comprises at least one admixture selected from the group consisting of water reducing agents, air entraining agents, gypsum and lime. A concrete structure produced by using the concrete composition according to claim 6.

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