KR101201924B1 - High Functional Binder Composition for Carbon Dioxide Reduction Displaying Properties of Early Strength - Google Patents

Abstract

The present invention relates to a binder composition for CO ₂ reduced type high-performance concrete exhibiting crude steel properties, more specifically, portland cement, blast furnace slag fine powder, fly ash, It is characterized by crude steel properties including hydrated lime, calcium sulfoaluminate (4CaO3Al ₂ O ₃ SO ₃ ) -based compounds (CSA) and mixtures containing release anhydride (CaSO ₄ ), clinker dust and phosphate magnesia. Exerting CO ₂ The present invention relates to a binder composition for reduced high performance concrete. The binder composition of the present invention contains a large amount of industrial by-products such as non-plastic materials, minimizes the amount of cement used, and uses a binder that exhibits the characteristics of clinker dust and crude steel, which are industrial by-products generated in the cement manufacturing process, thereby reducing the concrete strength according to the amount of cement used. It is an eco-friendly composition that plays a major role in environmental preservation by suppressing the amount of CO ₂ generated during cement manufacturing while greatly improving the degradation, and can be used as a high functional binder composition for concrete with excellent heat generation and salt resistance. Do.

Description

High Functional Binder Composition for Carbon Dioxide Reduction Displaying Properties of Early Strength}

The present invention is a CO ₂ exhibiting crude steel characteristics The present invention relates to a binder composition for reduced high performance concrete.

Recently, the government presented low carbon green growth as a new vision for the country. Green growth means pursuing both environmental preservation and economic growth, which have been perceived as contradictory values at the same time. The core is pursuing economic growth, while minimizing resource use and environmental pollution, and using it as a driving force for economic growth. To create a virtuous cycle.

Globally, environmental issues such as global warming due to greenhouse gases and exhaustion of natural resources are actively discussed. Particularly, in the IPCC Fourth Assessment Report published in 2007, global warming is certainly progressing. concluded that attributed to human activities such as the increase in CO ₂ emissions derived from fossil fuels, and further industrial revolution before 1750 to cut at least 50%, at least compared to 2000 in order to suppress enough 2.0 ~ 4.5 ℃ temperature rise in the previous since It is stated that there is a need.

The cement industry has contributed greatly to the industrial development of Korea as a national infrastructure industry. However, as the issue of the impact of heavy metals in cement on the human body has recently become a social issue, the cement product has been recognized as far from being environmentally friendly. . In the cement industry, the greenhouse gas emissions generated by the process of calcining natural resources such as limestone accounted for 37.4 million tons in 2005, accounting for 6.3% of the nation's total emissions. More than 60% of which is produced by the decarbonate reaction of limestone in the process. The cement CO ₂ reduced in the industry efforts are largely replace fuel used-up, CO ₂ reduction-type cement manufacturing technology, highly efficient equipment introduction technology and the CO ₂ capture and being divided into storage such as, and a double cement clinker production to reduce significantly The use of mixed cements can be particularly effective in reducing CO ₂ emissions.

The mixed materials used in the mixed cement are mainly blast furnace slag fine powder, fly ash or limestone fine powder. The use of mixtures not only reduces CO ₂ emissions by reducing the amount of clinker, but also improves the durability of chemical hydration and resistance to chlorine ion permeation through the improvement of hydration heat characteristics and high density of concrete. It is also suitable for manufacturing superfluid concrete.

However, Pozzolan materials such as blast furnace slag powder and fly ash react with calcium hydroxide, which is a hydration product of lime and cement, to form a stable insoluble compound. It may adversely affect the initial strength development of, and when the cement of Ca ion source is below a certain level, the reactivity of the pozzolanic material may not be activated, which may cause the strength and durability of the concrete to decrease. In addition, excessively increasing the amount of binder used or increasing the number of units for the development of concrete strength may result in poor workability due to the increase in the viscosity of the concrete and disadvantages in the economics of the structure due to the increase in the cost of concrete. It is true that there is a limitation in reducing the amount of cement used to make concrete and reduce CO ₂ emissions.

Accordingly, the present inventors are trying to develop an eco-friendly, high-functional binder composition that significantly reduces the amount of cement using a large amount of industrial by-products, while adding phosphate magnesia, calcium sulfoaluminate-based compound and release anhydrous gypsum mixture to a certain range. In this case, the decrease in initial strength due to the use of a large amount of industrial by-products is greatly improved, and when a mixture of slaked lime and high powder clinker dust generated during the cement manufacturing process is mixed, sufficient supply of Ca ions and filler action The present invention has been completed by confirming that excellent tissue strength expression and durability improvement are achieved by tissue compaction.

The purpose of the present invention is to improve the strength and durability of the concrete according to the use of a large amount of industrial by-products and the decrease in the amount of cement by using the above characteristic improvement agent to reduce the amount of CO ₂ generated by recycling industrial by-products and reducing the amount of cement used, It is, however, to provide a highly functional binder composition that can be used to produce high quality concrete.

In order to achieve the above object, the present invention is usually 10 to 20% by weight of portland cement, 30 to 80% by weight of blast furnace slag fine powder, 5 to 30% by weight of fly ash, slaked lime 1 to 5% by weight, 1 to 10% by weight of a mixture containing calcium sulfoaluminate (4CaO ₃ Al ₂ O ₃ -SO ₃ ) -based compound (CSA) and release anhydrous gypsum (CaSO ₄ ), clinker dust It provides a binder composition for CO ₂ reduced type high-performance concrete exhibiting crude steel properties, including 1 to 10% by weight and 1 to 3% by weight of phosphate magnesia.

Hereinafter, the present invention will be described in detail.

In the binder composition for CO ₂ reduced type high-performance concrete exhibiting the crude steel properties of the present invention, the weight ratio of CSA and release anhydride-free gypsum of the composition is preferably 1: 1 to 4, the brain of the clinker dust Specific surface area is 8,000 ~ 12,000 ㎠ / g, SO ₃ content is 2-5% by weight, K ₂ O + Na ₂ O content is preferably 1-5% by weight, the binder composition is cumulative heat of hydration after 3 days It is preferably 150 J / g or less, and the mortar compressive strength is preferably in the range of 20 to 30 MPa at 3 days of age, and 40 to 60 MPa at 28 days of age.

The present invention reduces the amount of ordinary Portland cement, which generates a large amount of CO ₂ during manufacture, to 1 to 20% by weight, and uses a large amount in the range of 30 to 80% by weight of blast furnace slag powder and 5 to 30% by weight of fly ash as an industrial by-product. It relates to an environmentally friendly binder composition for concrete. It contains 1 to 3% by weight of phosphate magnesia, which exhibits crude steel properties, to compensate for the decrease in strength due to the reduction of the amount of cement used in Portland, and 1 to 10% by weight of clinker dust and 1 to 9% of slaked lime produced during the cement manufacturing process to develop long-term strength. It relates to a CO ₂ reduced type high functional binder composition comprising 5% by weight, 1-10% by weight of a mixture of a calcium sulfoaluminate compound and a release anhydride gypsum.

As such, common Portland cement should contain 10 to 20% by weight, but when included below 10% by weight, the lack of a main binder for expressing the strength of concrete and the lack of a source of Ca ions for activating the reaction of other mixtures. This may cause problems in the strength of concrete, if more than 20% by weight does not meet the purpose of reducing the amount of CO ₂ that is the object of the present invention. In addition, the heat of hydration of the binder increases and may cause a temperature crack when applied to concrete, resulting in a reduction in durability of the concrete by reducing the durability of the concrete relatively due to the characteristics of the cement.

The fly ash content of the high functional binder to be developed through the present invention is preferably in the range of 5 to 30% by weight. In general, the fly ash has no hydraulic property in itself, but the silica component is calcium hydroxide, which is a hydration product of lime and cement. Since it has a property of slowly reacting with and generating a stable insoluble compound, it is preferable not to deviate from the range of use proposed in the present invention for reducing the heat of hydration and expression of long-term strength of concrete.

The blast furnace slag fine powder is a by-product generated in the steel mill, and the powder used in the present invention is finely pulverized and has a powder specific surface area of 4000-5000 cm 2 / g and a content of 30-80% by weight. In general, blast furnace slag fine powder does not reach fly ash, but has a certain effect of reducing the heat of hydration, and exhibits higher strength than fly ash by latent hydraulic properties. In the present invention, when the content is 30% by weight or less, there is a problem that the temperature cracking of the structure may occur by increasing the temperature difference between the inside and outside of the concrete due to excessive hydration heat caused by the hydration reaction of cement in the binder. In addition, if the content exceeds 80% by weight, not only problems in construction due to the decrease in the initial strength of the concrete, but also in the case of high blast furnace slag powder due to the characteristics of the blast furnace slag powder causes a rapid hydration reaction at high temperature, There is a problem that can act to increase the temperature sharply.

Clinker dust generated during the cement manufacturing process captures the fine powder generated during the grinding of the raw material of the clinker and the fine powder that is accompanied when hot air is discharged through the preheater of the raw material in the kiln. At least% by weight is limestone, and is composed of fine powder of other raw materials.

Blaine specific surface area of clinker dust is preferably in the range of 8,000 to 12,000 cm 2 / g, because fine clinker dust particles act as fillers in concrete hardeners, and thus exhibit an excellent effect on the long-term strength of concrete. The content of SO _{3 in} clinker dust is preferably 2 to 5% by weight. SO ₃ is present in the form of _three anhydrous gypsum, which controls the initial reaction of ordinary portland cement and promotes the reactivity of the blast furnace slag powder to show the potential hydraulic properties. If it is less than 2% by weight, the effect is insignificant, and if it is more than 5% by weight, there is a problem of excessively delaying the reaction of the ordinary portland cement. In addition, K ₂ O and Na ₂ O is a strong alkali to promote the latent hydrophobic and pozzolanic reaction of the blast furnace slag powder and fly ash contained in the present invention will have an excellent effect on the strength expression of the binder. At this time, if the total content of K ₂ O and Na ₂ O is less than 1% by weight, the effect of promoting reactivity is insignificant, and if it is more than 5% by weight, due to the high solubility of alkali, the workability of concrete and the long term due to rapid initial strength development It causes a decrease in strength expression. The above clinker dust should be contained in the level of 1 to 10% of the combination. If it is less than 1% by weight, the effect is insignificant, and if it is more than 10% by weight, the unit yield of concrete increases due to the increase in the absorption rate due to high fine powder, thereby decreasing the strength. Can cause.

Calcium sulfoaluminate-based compounds react with heteroanhydric gypsum to produce ettringite. Ettrinzite is a needle-shaped crystal that densifies concrete structure and shows excellent effect on strength development. In the present invention, it is preferable to mix the mixture at 20 to 50% by weight of calcium sulfoaluminate compound and 50 to 80% by weight of calcium sulfate, and calcium sulfate present as an anhydrous gypsum has relatively low solubility in initial strength. When it is less than 50% by weight, the formation of ethrinzite is insufficient when the weight is less than 50% by weight, and the strength is insufficient. When the concentration is more than 80%, the initial setting of concrete is adversely affected by the excessive coagulation delay effect. When the compound is less than 1% by weight, the effect of strength expression may not be exhibited due to the lack of the amount of ethrinite produced for strength expression. If the compound is more than 10% by weight, the expansion pressure caused by excessive ethrinite generation may cause volume expansion of the concrete. This can cause serious problems in the durability of the structure.

In the present invention, the slaked lime should be included in 1 to 5% by weight, and the slaked lime releases Ca ions when reacted with water to promote the reaction between the industrial by-product blast furnace slag powder and fly ash to play a major role in long-term strength expression. At this time, when the slaked lime is less than 1% by weight, it is difficult to express long-term strength due to the lack of Ca ions, and when the slaked lime is more than 5% by weight, the workability of concrete and the increase of heat of hydration are increased due to the rapid reactivity of slaked lime.

The main component of phosphate magnesia is magnesia oxide and ammonium monophosphate, which is a crude steel binder that produces a cured product that exhibits stability and compressive strength similar to that of ordinary portland cement by acid-base reaction. In particular, it has an excellent effect on the immobilization and stabilization of heavy metal ions, which are insoluble compounds, and unlike cement, it does not have strong alkalinity and has advantages in terms of environment friendliness. In the binder composition of the present invention, including the phosphate magnesia in the range of 1 to 3% by weight, it is possible to contribute to the reduction of the air due to premature curing of concrete by improving the initial strength decrease due to the lack of ordinary Portland cement content, including 1% by weight or less. If the effect is insignificant, and when it contains more than 3% by weight, the rapid reaction of phosphate magnesia causes a decrease in workability and a decrease in strength expression due to coagulation.

In the present invention, a binder composition for concrete was prepared by mixing ordinary portland cement, blast furnace slag fine powder, fly ash, clinker dust, CSA, release anhydrous gypsum, slaked lime and phosphate magnesia in various weight ratios (see Table 1 ). In addition, as a result of examining their compressive strength expression characteristics (see Table 2 ), despite the reduction in cement content, it shows excellent long-term strength expression similar to the initial strength expression compared to the conventional composition. The ratio of the clinker dust and calcium sulfoaluminate compound to the anhydrous gypsum plays an important role in the performance of the binder composition. As a result of examining the hydration exothermic properties of each binder (see Table 4 and FIG. 1 ), the composition belonging to the present invention exhibits lower hydration exothermic properties than the conventional composition. In addition, in the concrete properties, the composition of the present invention exhibits excellent workability due to improved slump, and exhibits excellent roughing properties even in concrete compressive strength (see FIG. 3 ). Concrete durability evaluation was evaluated by calculating the salt diffusion coefficient of each binder (see Fig. 4 ), the composition of the present invention exhibits a low salt diffusion coefficient due to the densification of the texture of ethrinzite to express excellent durability performance.

As described above, the binder composition according to the present invention plays a major role in environmental preservation by suppressing the amount of CO ₂ generated during cement production by minimizing the amount of cement containing a large amount of non-plastic material, and occurring in the cement manufacturing process. By using a mixture of industrial by-products such as clinker dust, hydrated lime, calcium sulfoaluminate compound and hetero-anhydrous gypsum, and phosphate magnesia exhibiting crude steel properties, the concrete strength reduction is greatly improved due to the decrease of cement usage. It is possible to make an excellent contribution to the manufacture of high-quality concrete through improved durability, such as improved construction properties, reduced hydration calorific value and increased salt shielding.

1 is a graph comparing the hydration calorific properties of each binder for Examples 1 and 3, Comparative Examples 1 to 3 of the present invention, it was measured the heat of microhydration for 72 hours at 20 ℃, W / B 50% conditions ,
FIG. 2 is a graph comparing the concrete slump characteristics of Examples 1 to 3 and Comparative Examples 2 to 4;
3 is a graph comparing the compressive strength of each concrete for Examples 1 to 3 and Comparative Examples 2 to 4,
4 is a graph comparing the concrete salinity diffusion coefficients of Examples 1 to 3 and Comparative Examples 2 to 4;

Hereinafter, the present invention will be described in more detail based on the following examples. It should be noted, however, that the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The present invention is not limited to the following examples. Will be apparent to those skilled in the art to which the present invention pertains.

<Examples 1 to 4 and Comparative Examples 1 to 10> Composition ratio of the binder composition for concrete

Table 1 below shows the powder mixing ratios of the examples and comparative examples belonging to the present invention.

Powder compounding condition (wt%) Common Portland Cement Gorothal ragme powder Fly ash Clinker Dust CSA Anhydrous gypsum Lime lime Phosphate Magnesia Limestone Example 1 10 54 20 5 One 4 5 One Example 2 10 54 20 5 2 3 5 One Example 3 20 56 10 5 One 4 3 One Example 4 20 46 20 5 2 3 3 One Comparative Example 1 100 Comparative Example 2 40 40 20 Comparative Example 3 30 40 30 Comparative Example 4 10 70 20 Comparative Example 5 20 60 20 Comparative Example 6 10 60 20 5 2 3 Comparative Example 7 20 55 20 5 Comparative Example 8 10 54 20 2 3 5 One 5 Comparative Example 9 10 65 20 One 4 Comparative Example 10 10 60 20 3 2 5

Test Example 1 Evaluation of Compressive Strength Expression Characteristics

The compressive strength expression characteristics of the high functional binder composition belonging to the present invention through Examples 1 to 4 were compared with Comparative Examples 1 to 8 according to KS L ISO 679. The results are shown in Table 2 below.

Mortar Compressive Strength (MPa) 1 day 3 days 28 days Example 1 8.3 22.6 42.1 Example 2 8.9 21.4 41.5 Example 3 6.0 25.3 49.2 Example 4 5.7 24.2 48.4 Comparative Example 1 17.5 34.1 58.3 Comparative Example 2 7.0 19.3 55.6 Comparative Example 3 4.9 14.6 46.9 Comparative Example 4 4.3 11.2 30.7 Comparative Example 5 4.2 13.2 44.9 Comparative Example 6 8.6 16.9 29.9 Comparative Example 7 3.1 16.1 44.1 Comparative Example 8 6.9 18.4 27.3 Comparative Example 9 5.5 18.9 29.5 Comparative Example 10 1.9 13.3 34.0

As a result, in the case of the embodiment of the present invention, the initial strength of 20 MPa or more at the age of 3 days by expressing the crude steel properties, the 28 days of the age expressing more than 40 MPa strength, compared with recently used as a low heat generation cement Compared with Examples 2 and 3 showed excellent initial strength expression. In addition, despite the decrease in cement content, similar results were obtained in long-term strength development. In addition, as shown in Comparative Examples 4 to 10, when out of the range of the binder composition belonging to the scope of the present invention, the compressive strength expression performance to be obtained in the present invention by reducing the initial strength expression and reduced long-term strength expression due to the lack of cement content Could not be obtained.

Test Example 2 Clinker Dust Components and Properties

Table 3 below shows the chemical composition of the limestone fine powder at the same brain powder level as the clinker dust used in the present invention.

Chemical composition (weight ratio) Powder figure
(Cm 2 / g) SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO SO ₃ K ₂ O Na ₂ O Intensity
outage Clinker
Dust 10.06 3.92 2.59 38.59 2.73 2.00 3.67 0.28 36.24 10,000 Limestone
Fine powder 1.10 0.56 0.06 54.76 0.30 0.28 - - 40.83 10,000

In the case of Comparative Example 8 using fine limestone powder instead of clinker dust, the long-term strength expression was poor due to lack of SO ₃ and alkali content. Therefore, it was confirmed that the chemical composition of the clinker dust plays an important role in the performance of the binder composition.

In addition, although not described in the comparative example, when the ratio of the calcium sulfoaluminate compound and the release anhydrite gypsum is outside the composition range of the present invention, the amount of ettringite (hydration mineral) produced due to the lack of release anhydride gypsum is insufficient. As a result, it was confirmed that the strength expression was poor.

<Test Example 3> Evaluation of hydration fever characteristics

In order to examine the heat generation characteristics of each binder, the heat of microhydration was measured for 72 hours at 50 ° C. at 20 ° C., and the results are shown in Table 4 and FIG. 1. Comparative Example 1 using 100% by weight of ordinary Portland cement showed a high hydration calorific value of 260 J / g. In addition, Comparative Examples 2 and 3, which are general low heat generation cements, exhibit hydration exotherm of 140 J / g or more, whereas Examples 1 and 3 belonging to the present invention exhibit hydration exothermic properties of 140 J / g or less. Therefore, it was confirmed that the composition of the present invention exhibits excellent performance compared to general low heat generation cement for controlling the heat of hydration of concrete.

Formulation Name Example 1 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 72 hours cumulative sign language
(J / g) 133.04 140.49 266.71 152.30 141.49

Test Example 4 Concrete Properties

Concrete mixture prepared using the binder is shown in Table 5 below.

Formulation Name W / B
(%) S / a
(%) Binder
(kg / m ³ ) WR made
(kg / m ³ ) slump
(mm) Air
(%) Concrete Compressive Strength (MPa) 3 days 7 days 28 days Example 1 47.9 47.0 334 2.75 190 4.0 11.7 21.6 28.3 Example 2 190 4.1 12.2 20.9 27.9 Example 3 200 4.3 11.2 21.1 31.6 Comparative Example 2 180 4.7 9.8 16.9 30.5 Comparative Example 3 170 4.3 6.8 14.5 26.7 Comparative Example 4 200 4.2 5.7 12.7 20.7

In the case of concrete workability, as shown in Figure 2, when the same unit amount and admixture amount was applied, it was confirmed that the embodiment of the present invention shows an excellent workability slump is improved compared to the various comparative examples.

In addition, in the case of the concrete compressive strength, as shown in Figure 3, the embodiment of the present invention exhibits excellent crude steel properties, showing excellent results at 3 to 4 MPa level at 3 days compared to the comparative example, and at 28 days general Compared with Comparative Examples 2 to 3 which is a low heat generation cement, it was confirmed that the same or more strength expression characteristics were shown.

Concrete durability evaluation was evaluated by calculating the salt diffusion coefficient of each binder according to the NT Build 492 test method. As shown in FIG. 4, the mixed cement containing a relatively high amount of fine powder by-products shows a lower salt diffusion coefficient from the initial stage than ordinary portland cement, and particularly the fine powder clinker dust and calcium sulfoaluminate compound and release anhydride. Examples 1 and 2 to which the gypsum mixture was added showed lower salt diffusion coefficient than Comparative Examples 2 and 3 and showed excellent durability by the filler action of clinker dust and the densification of ethrinite produced by the mixture. Confirmed.

On the other hand, the specific scope of the present invention is defined by the claims rather than the embodiments described above, all changes and modifications derived from the meaning and scope and equivalent concepts of the claims to the scope of the invention It should be interpreted as including.

Claims (4)

10 to 20% by weight of portland cement, 30 to 80% by weight of blast furnace slag, 5 to 30% by weight of fly ash, 1 to 5% by weight of lime, calcium sulfoaluminate 1 to 10% by weight of a mixture containing (4CaO ₃ Al ₂ O _{3 to} SO ₃ ) -based compound (CSA) and release anhydrous gypsum (CaSO ₄ ), 1 to 10% by weight of clinker dust and phosphate magnesia ) CO ₂ reduced type high functional concrete binder composition exhibiting crude steel properties comprising 1 to 3% by weight.
According to claim 1, wherein the weight ratio of the CSA and the release anhydride-free gypsum is a binder composition for CO ₂ reduced type high-performance concrete exhibiting crude steel characteristics, characterized in that 1: 1 to 4.
According to claim 1, The brain surface (blaine) specific surface area of the clinker dust (8,000-12,000 cm 2 / g, SO ₃ content is 2 to 5% by weight, K ₂ O + Na ₂ O content is 1 to 5% by weight) CO ₂ reduction type high functional concrete binder composition exhibiting the characteristics of crude steel.
According to claim 1, wherein the binder composition has a cumulative heat of hydration of 150 J / g or less after the first three days of age, mortar compressive strength of 20 ~ 30 MPa at age 3, 40 to 60 MPa range at 28 days of age CO ₂ reduction type high functional concrete binder composition exhibiting crude steel properties.

Images