KR20130048482A - Binder composition for concrete comprising bottom ash - Google Patents

Abstract

PURPOSE: A binder composition for concrete is provided to include an ash mixture with bottom ash and fly ash, blast furnace slag micropowder, and Portland cement, thereby having excellent chemical resistance, salt resistance, and durability. CONSTITUTION: A binder composition for concrete comprises: 10-30wt% of ash mixture which comprises 5-50wt% of bottom ash and 50-95wt% of fly ash; 30-50wt% of blast furnace slag micropowder; and 30-40wt% of Portland cement. The brain specific surface area of the ash mixture is 6,000-8,000cm^2/g. The ash mixture is manufactured by mechano-chemical treatment in a condition which physical energy of 50-150KJ/s per unit meter(m^3) is applied. The ash mixture is mechano-chemical treated by being pulverized using a mill for 30-120 minutes. Accumulated hydration heat after 3 days is 120-170J/g. [Reference numerals] (AA) Example 1; (BB) Example 2; (CC) Comparative example 1; (DD) Comparative example 2; (EE) Comparative example 3

Description

Binder Composition for Concrete Comprising Bottom Ash}

The present invention (a) an ash mixture comprising a bottom ash and fly ash; (b) blast furnace slag fine powder; And (c) a binder composition for concrete comprising portland cement, relates to a binder composition for concrete excellent in chemical resistance, salt resistance and durability.

Bottom ash is a type of coal ash and accounts for about 20% by weight of the total ash produced in Korea. The bottom ash is attached to the furnace wall, superheater, reheater, etc. of the thermal power plant, and falls to the bottom of the boiler by its own weight. The particle diameter is about 1-2.5 mm. The bottom ash collected in the lower part of the boiler is crushed by a grinder, sent to a transfer tank, and sent to a reprocessing plant by operation of a high pressure pump with fly ash and water which are not recycled, and then landfilled. have.

In general, the particles of the bottom ash is bulky and similar in particle size to sand, so that the technology of utilizing the bottom ash as a substitute for fine aggregates in concrete is described in Korean Patent No. 378076 “High Flow Filling Composition Containing Bottom Ash and a Method for Manufacturing the Same”. This is introduced. In addition, the particles of the bottom ash has a low specific gravity and high absorption rate due to porosity, the technology of utilizing the bottom ash as a lightweight aggregate in the "sound-absorbing soundproof panel using the low-weight lightweight aggregate" of the Republic of Korea Patent No. 747619.

However, since the bottom ash has a relatively high degree of melting and low activity, the development of technology for use as a cement mixture is very poor.

On the other hand, coal ash is an industrial by-product from coal-fired power plants. In 2005, about 5.9 million tons were generated in Korea alone. As the annual increase increases, efficient treatment of coal ash has emerged as a new problem at national level. To this end, the government enacted the "Recycling Guidelines for Steel Slag and Coal Ash Distributors" from 1993 to promote the recycling of industrial by-products, and established recycling laws and recycling plans according to the specifications for each use. The company has been at the forefront of recycling coal ash. As a result, the recycling rate, which was below 20% by 1995, reached a maximum recycling rate of 78.7% in 2003, reaching the level of developed countries.

The recycling sector where coal ash is currently used is shown in Table 1 below:

Field Usage Technology Overview Cement field Cement raw material
Cement mixture
Ready Mixed Concrete Can substitute 4-5% of the amount of raw materials as a substitute for clay among cement raw materials
Less than 5% miscible in Portland cement
5-30% can be mixed depending on the type
General ready mixed concrete can be mixed about 10%
Mass concrete can be mixed 20-39% Architecture Artificial lightweight aggregate
Roof tile, ceramic
Foam Concrete
Cement secondary products Can be used as a substitute for gravel to reduce the weight of tall buildings
Use as a clay substitute
Excellent insulation when using aerated concrete
Block, fume pipe, electric pole, price Civil engineering Asphalt Filler
Norbanjae
Sang Jae Noh
Landfill, fill
filling
Grout construction Asphalt Stabilization and Aggregate Crevice Fillers
Cement stabilized roadbed, replacement of lime stable roadbed
Reclamation work, land reclamation, or fill reclamation
Use as a filler for ash, gang

The recycling of coal ash can replace the depleted natural resources, and has become an alternative to reduce the environmental pollution caused by the reclamation of coal ash.

However, this recycling is mostly due to the increased use of fly ash as cement clinker raw materials and cement mixtures, and the use of bottom ash is relatively limited and the recycling rate is extremely low. In addition, the bottom ash is currently being disposed of mostly landfill causing serious environmental pollution.

Therefore, in recent years, various studies on the recycling of bottom ash have been actively conducted.

Recently, as the demand for investment in national social indirect capital has increased, the size of civil engineering and building structures has been accelerated and specialization has been accelerated, and important structures such as concrete foundations, offshore structures, and nuclear power plants are being cast into mass concrete. It tends to become high strength concrete. With the change of concrete structure, the development of new construction method and required performance for concrete materials are gradually diversified, and the use of special binders for concrete with special functions is increasing rapidly to satisfy them.

In particular, the construction of large offshore structures facing the sea and the sea has increased, and it is urgent to develop high functional binders to prevent the temperature cracking of the structure due to the heat of hydration of concrete during the early age and the deterioration of concrete due to salt damage under the marine environment.

As described above, in order to reduce durability of heat of hydration of concrete and to improve durability such as resistance to salt damage, the use of mixed cements containing a large amount of pozzolanic has been increased.

In particular, the currently used mixed cement not only improves the heat of hydration properties of concrete by pozzolanic materials but also improves durability such as chemical resistance and chlorine ion penetration resistance through high density, and due to low specific gravity and proper rheological properties, It is also suitable for the production of fluidized concrete. For example, conventionally, by mixing bottom ash with mixed cement as a pozzolanic material, concrete having excellent water permeability and chemical resistance as well as other pozzolanic materials can be produced.

However, since the particles are coarse and the degree of melting is relatively low, the activity is relatively low, the strength is lowered, and the absorption rate is high, which impairs the workability of the concrete.

Republic of Korea Patent Registration No. 10-378076 Republic of Korea Patent No. 10-747619

The present inventors have tried to develop concrete having excellent chemical resistance, salt resistance and durability using bottom ash. As a result, an ash mixture containing bottom ash and fly ash in a specific content was prepared by mechanochemical treatment, and this was mixed with blast furnace slag powder and portland cement in a specific content to prepare a binder composition for concrete. It is improved, exhibits a cumulative heat of hydration of 170 J / g or less, when included in the concrete mixed material, the workability of the concrete is improved, the workability is improved, excellent long-term strength and salt resistance is very excellent durability By confirming, the present invention was completed.

Accordingly, it is an object of the present invention to provide a binder composition for concrete.

Other objects and advantages of the present invention will become more apparent from the following detailed description of the invention, claims and drawings.

According to one aspect of the invention, the present invention (a) 10-30% by weight of the ash mixture comprising 5-50% by weight bottom ash and 50-95% by weight fly ash; (b) 30-50% by weight of blast furnace slag powder; And (c) 30-40% by weight of Portland cement.

The present inventors have tried to develop concrete having excellent chemical resistance, salt resistance and durability using bottom ash. As a result, an ash mixture containing bottom ash and fly ash in a specific content was prepared by mechanochemical treatment, and this was mixed with blast furnace slag powder and portland cement in a specific content to prepare a binder composition for concrete. It is improved, exhibits a cumulative heat of hydration of 170 J / g or less, when included in the concrete mixed material, the workability of the concrete is improved, the workability is improved, the excellent long-term strength and salt resistance is very excellent durability Confirmed.

As used herein, the term "mechanochemical treatment technique" is a method of changing the bonding state of a material by mechanical energy to change the physical and chemical properties of the material or by changing the reaction result with surrounding materials. It is a non-heating operation and refers to a unique processing technique that can synthesize or decompose materials that cannot be obtained in a heating operation. The present invention is used to carry out nanoscale material evaluation, which takes place at the atomic or molecular level because of the use of this technique, and conventionally BaCO ₃ In addition, excellent results were found in the field of uniform composition of TiO ₂ by mixing, increasing reaction speed by activation, and improvement of memory characteristics by grinding in the manufacturing process of ferrite memory core.

Accordingly, in the present invention, the bottom ash surface was activated through a mechanochemical treatment method to confirm the applicability of the cement mixture.

The binder composition for concrete of the present invention is largely (a) ash mixture; (b) blast furnace slag fine powder; And (c) portland cement, wherein the ash mixture (a) comprises a bottom ash and a fly ash.

Bottom ash and fly ash included in the ash mixture of the present invention are industrial by-products generated in a thermal power plant, and their main components are SiO ₂ , Al ₂ O ₃ , CaO and Fe ₂ O ₃ .

For bottom ash, 40-50 wt% SiO ₂ , 20-30 wt% Al ₂ O ₃ , CaO 2-10 wt%, Fe ₂ O ₃ 10-20 wt% and other components based on the total weight of the bottom ash It is preferable to use a bottom ash containing 0.1-5% by weight, and in the case of a fly ash, 60-70% by weight of SiO ₂ , 10-20% by weight of Al ₂ O ₃ , CaO 2-10% by weight, Fe ₂ O ₃ Preference is given to using fly ash comprising 2-10% by weight and 0.1-5% by weight of other components.

Further, the bottom ash used in the present invention has a density of 2-4 kg / m ³ and the fly ash has a density of 1.5-3 kg / m ³ , and more preferably, the bottom ash has a density of 2-3 kg. / m ³ and fly ash has a density of 2-2.7 kg / m ³ , even more preferably bottom ash has a density of 2.4-2.8 kg / m ³ and fly ash has a density of 2-2.4 kg / m ³ .

According to a preferred embodiment of the invention, the ash mixture comprises 25-50% by weight bottom ash and 50-75% by weight fly ash based on the total weight of the ash mixture.

When the content of the bottom ash in the ash mixture is less than 5% by weight, the content of the bottom ash, which is relatively durable, is insufficient, thereby reducing the water permeability, chemical resistance, and salt resistance of the concrete. As a result, there is a problem of shortening the durability life of the structure, and if it exceeds 50% by weight, the content of the bottom ash having a relatively high porosity increases and the fly ash contributes to the surface treatment of the bottom ash by mechanochemical treatment. Insufficient content has the disadvantage of deterioration of workability and compressive strength during concrete production.

The ash mixture included in the binder composition for concrete of the present invention is prepared by carrying out a mechanochemical treatment, and the mechanochemical treatment may be carried out by various methods known in the art, and preferably, the surface treatment of the bottom ash After the fly ash is added to the bottom ash to increase the activation through, it is carried out using a vibration mill.

Specifically, 1.0-1.5 liters of the sample is introduced into a 8.0 L cylindrical grinding container filled with 2.5-3.0 L of steel balls having a diameter of 8 mm, and mechanochemical treatment is performed by applying physical energy.

According to a preferred embodiment of the present invention, the ash mixture is mixed by mechanochemical treatment under the conditions of applying a physical energy of 50-150 KJ / s per unit volume of ash mixture (m ³ ), more preferably the physical The energy is 80-120 KJ / s per unit volume of ash mixture (m ³ ), and even more preferably the physical energy is 90-110 KJ / s per unit volume of ash mixture (m ³ ).

According to another preferred embodiment of the invention, the ash mixture is ground by vibrating mill for 30-120 minutes and mixed by mechanochemical treatment, more preferably by grinding by vibrating mill for 45-90 minutes, even more preferably Grind with a vibration mill for 60-90 minutes.

In general, pulverization is carried out for the purpose of promoting uniform reaction by accelerating the reaction rate of the powder. The achievement of the mechanochemical reaction using the grinder may depend on the type, size, or operating conditions of the grinder used. In particular, in the field of cement, grinding mills such as ball mills or roller mills are generally used to grind cement raw materials. In the case of a ball mill, the grinding media are moved upwards along the inner wall of the cylinder by centrifugal force, and then are dropped by applying an impact force to the grinding material while falling.The roller mill rotates 3-4 rollers in the mill on a disk. It is a method that uses the principle that the pulverized material is crushed by the compression and friction force between the roller, the disc and the inner wall by simultaneously revolving the whole.

However, in the vibration mill used in the present invention, while the whole mill is vibrated by a circle having an eccentricity, the grinding media such as balls or bars in the mill simultaneously deliver impact and frictional forces to the mill, thereby grinding the mill to a micron (μm) unit. By supplying a large amount of pulverization energy to the pulverized product within a short time, the properties of the pulverized raw material can be changed physically and chemically.

Therefore, when the bottom ash and fly ash are mixed and pulverized using a vibration mill, the particles of the fly ash are physically bonded to the surface of the particles of the bottom ash, thereby increasing the chemical affinity of the bottom ash as the affinity between the particles increases. You can get results.

The ash mixture comprising the bottom ash and the fly ash is included in 10-30% by weight, more preferably in 15-25% by weight, most preferably 20% by weight, based on the total weight of the binder composition for concrete. %to be. Generally, ash ash, such as bottom ash and fly ash, is not hydraulic in itself, but since the silica component reacts slowly with calcium hydroxide, which is a hydration product of coal ash and cement, it produces a stable insoluble compound and hardens it. When included in the content of the composition of the invention shows the effect of reducing the heat of hydration and initial strength of concrete.

According to another preferred embodiment of the present invention, the ash mixture has a brain specific surface area of 6000-8000 cm ² / g, more preferably a brain specific surface area of 6000-7000 cm ² / g, even more preferably The brain specific surface area is 6000-6500 cm ² / g, even more preferably the brain specific surface area is 6000-6300 cm ² / g.

When the brain specific surface area of the particles of the crushed ash mixture is less than 6000 cm ² / g, the reduction of the specific surface area and the chemical activity according to the desired surface activity in the present invention can not be achieved, which leads to delay in early strength expression of concrete. In addition, when it exceeds 8000 cm ² / g, the workability occurs when pouring due to the increase of the viscosity of the concrete, it is not preferable in terms of economics due to the increase in manufacturing cost.

In addition, the blast furnace slag used in the composition of the present invention is a by-product generated in the steel mill, and non-ferrous components contained in iron ore, coke, and limestone charged in the blast furnace are melted, and SiO ₂ and CaO are mainly composed of inorganic substances, and are recycled. This is a possible material.

In particular, the blast furnace slag fine powder, which has undergone pulverization process, produces calcium silicate, calcium aluminate and calcium aluminosilicate hydrate by alkali stimulation, and has a latent hydraulic property that forms a hydrate even as the powder itself. Indicates. It is generally less than coal ash, but has some effect of reducing heat of hydration.

The blast furnace slag powder is included in the binder composition for concrete 30-30% by weight based on the total weight, more preferably 40-45% by weight.

If the content of blast furnace slag powder is less than 30% by weight, the temperature difference between the inside and outside of the concrete may increase due to excessive hydration heat caused by the hydration reaction of cement in the binder composition, which may cause temperature cracking of the structure, and the content is 50% by weight. In case of exceeding, it causes problems in construction due to the decrease in initial strength of concrete, and when the concrete's casting temperature is high, it causes a rapid hydration reaction at high temperature due to the characteristics of blast furnace slag fine powder, thereby rapidly raising the internal temperature of concrete. There is a problem that can work.

On the other hand, the powder degree showing the particle size of the binder has a great influence on the hydration reaction rate of the binder. When the quality of the binder is constant, the number of particles in a certain weight, the larger the specific surface area (the finer), the greater the hydration effect, so that the condensation is faster and the early strength is high, the workability is good, and the structure is dense, so that water does not pass after construction. There is a nature. On the other hand, if the specific surface area is too large, the heat of hydration is generated due to the rapid initial reactivity when concrete is condensed, which is likely to cause early cracking and weathering when cement is stored for a long time. Because of this, the cementity of the cement may not be too large or too small.

Therefore, the blast furnace slag fine powder used in the present invention preferably has a specific surface area of 4000-5000 cm ² / g. When the specific surface area of the blast furnace slag powder is less than 4000 cm ² / g, the hydration activity may be reduced, which may delay the development of premature strength of concrete, and when it exceeds 5000 cm ² / g, Excessive heat of hydration is generated there is a problem that can cause a temperature crack in the concrete.

According to another preferred embodiment of the present invention, the blast furnace slag fine powder used in the present invention has a density of 2-4 kg / m ³ , more preferably a density of 2.5-3.5 kg / m ³ , even more preferably The density is 2.5-3 kg / m ³ .

In addition, Portland cement included in the composition of the present invention is included in 30-40% by weight, more preferably 35-40% by weight based on the total weight of the binder composition for concrete of the present invention. If the content of the Portland cement is less than 30% by weight, the lack of a main binder for expressing the strength of the concrete and the lack of a source of Ca ions for activating the reaction of other mixtures cause problems in concrete strength. If exceeded, the heat of hydration of the concrete may increase, causing temperature cracking, and due to the characteristics of the cement, the durability of the concrete may be relatively reduced, resulting in a problem of shortening the durability life of the structure.

According to another preferred embodiment of the invention, the composition has a cumulative heat of hydration 120-170 J / g after 3 days of age.

As the cumulative hydration rate of the composition of the present invention has the above range, the heat of hydration as a whole can be expected to be excellent in preventing temperature cracking that may occur in the mass concrete or ultra high-strength concrete used in large structures, and marine structures adjacent to the sea When applied to the pozzolanic reaction, the concrete structure is densified to improve the durability and consequently exhibits excellent performance in preventing deterioration of the structure.

The features and advantages of the present invention are summarized as follows:

(Iii) the present invention comprises (a) an ash mixture comprising a bottom ash and a fly ash; (b) blast furnace slag fine powder; And (c) relates to a binder composition for concrete comprising portland cement.

(Ii) The ash mixture included in the composition of the present invention is prepared through mechanochemical treatment, and the ash mixture shows excellent workability and activity results, thereby improving surface activity, thereby improving the strength of the concrete. Indicates.

(Iii) In addition, the composition of the present invention exhibited a cumulative heat of hydration of 170 J / g or less after 3 days of age, showing excellent performance in controlling the heat of hydration of concrete.

(Iii) On the other hand, the composition of the present invention is included in the concrete mixed material, the amount of admixture for obtaining the same slump is reduced, the workability of the concrete is improved, the workability is improved, and excellent long-term by the pozzolanic reaction of the surface-treated bottom ash It is excellent in durability due to its strength and resistance to salt damage.

(Iii) Therefore, the composition of the present invention can expand the recycling range of the bottom ash to provide environmentally-friendly high quality concrete, and can reduce the cost of the final product.

1 is a graph showing a particle size distribution of an ash mixture including a bottom ash and a fly ash prepared according to an embodiment of the present invention.
Figure 2 is a graph showing the cumulative heat of hydration of the binder for concrete prepared according to another embodiment of the present invention.
Figure 3 is a graph showing the amount of slump and admixture of concrete prepared according to another embodiment of the present invention.
Figure 4 is a graph showing the compressive strength of the concrete produced according to another embodiment of the present invention.
5 is a graph showing the amount of charge passing through the concrete produced according to another embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for describing the present invention in more detail and that the scope of the present invention is not limited by these embodiments in accordance with the gist of the present invention .

Example

Throughout this specification, "%" used to denote the concentration of a particular substance is intended to include solids / solids (wt / wt), solid / liquid (wt / The liquid / liquid is (vol / vol)%.

Preparation Example 1-2 and Comparative Preparation Example 1-3: Preparation of Ash Mix

The chemical composition of each material used in the concrete binder of the present invention is shown in Table 2 below:

Name of sample Chemical composition (% by weight) density
(kg / m ³ ) CaO Al ₂ O ₃ SiO ₂ SO ₃ MgO Fe ₂ O ₃ Na ₂ O K ₂ O Cl Bottom ash 8.5 25.3 43.5 0.8 0.4 15.2 0.2 1.5 - 2.60 Fly ash 3.0 19.5 67.6 - 1.3 4.5 1.7 1.0 - 2.20 Common Portland Cement 58.9 6.8 21.7 2.0 2.3 3.5 0.1 1.0 - 3.09 Blast Furnace Slag Powder 43.3 15.2 33.8 2.5 3.9 0.5 - 0.3 - 2.91

For the mechanochemical treatment of the ash mixture, the bottom ash and fly ash were mixed with 1.0-1.5 L of 8 mm diameter steel balls with 2.5-3.0 L of steel balls, and 1.0-1.5 L of the ash ash was added. 100 KJ / s of physical energy per unit volume (m ³ ) of the ash mixture was added and ground for 60 minutes using a vibration mill (manufacturer: Woongbi Machinery, equipment name: TBM2L) (Preparation Example 1-2 and Comparative Preparation). Example 2-3). General fly ash was used as Comparative Preparation Example 1 to evaluate the physical properties of the sample.

Name of sample Powder blending condition Bottom ash
(weight %) Fly ash
(weight %) Grinding time
(minute) Production Example 1 25 75 60 Production Example 2 50 50 Comparative Preparation Example 1 0 100 0 Comparative Production Example 2 75 25 60 Comparative Production Example 3 100 0

Test Example  One: Ash mixture  Particle size distribution, physical properties and activity assessment

Particle size distribution and physical properties of the samples of Preparation Example 1-2 and Comparative Preparation Example 1-3 are shown in FIG. 1 and Table 4 below.

Name of sample Physical Characteristics Center particle size
(Μm) Brain Specific Surface Area
(cm < ² > / g) 45㎛ residue
(%) Production Example 1 9.48 6251 0.10 Production Example 2 11.00 6032 0.33 Comparative Preparation Example 1 18.62 3757 8.33 Comparative Production Example 2 12.42 5832 0.17 Comparative Production Example 3 13.75 6492 0.17

In addition, the activity test was conducted in accordance with KSL 5405 to evaluate the reactivity of the prepared sample as described above, and compared with the general fly ash (Comparative Preparation Example 1) to evaluate the physical properties of the sample, the results are summarized in Table 5. :

Name of sample Activity evaluation result Flow
Ratio (%) Activity index (%) 7 days 28 days 91 days Production Example 1 111 93 105 121 Production Example 2 106 88 109 127 Comparative Preparation Example 1 106 83 101 110 Comparative Production Example 2 101 82 101 118 Comparative Production Example 3 99 81 98 112

As shown in FIG. 1 and Tables 4 and 5 attached below, the bottom ash content of up to 50% by weight shows excellent workability and activity results compared to a general fly ash, but exceeds 50% by weight of the flow ratio is reduced. In addition, the initial strength expression also showed a tendency to decrease.

Manufacturing example  3: Manufacture of binder for concrete

Mechano-chemically treated ash mixture, ordinary portland cement and blast furnace slag fine powder in Preparation Example 1-2 and Comparative Preparation Example 1-2 were mixed in the content ratios shown in Table 6 to prepare a binder for concrete.

Name of sample Powder compounding condition (wt%) Common Portland Cement Low Heat Portland Cement Blast Furnace Slag Powder Ash mixture Production Example 1 Production Example 2 compare
Production Example 1 compare
Preparation Example 2 Example 1 35 - 45 20 - - - Example 2 35 - 45 - 20 - - Example 3 40 - 40 20 - - - Comparative Example 1 35 - 45 - - 20 - Comparative Example 2 35 - 45 - - - 20 Comparative Example 3 30 - 70 - - - - Comparative Example 4 - 100 - - - - - Comparative Example 5 100 - - - - - -

Test Example  2: concrete Binders  Of the composition Hydration Fever  Property evaluation

In order to examine and compare the hydration heating characteristics of each binder of Preparation Example 3, the measurement of the heat of hydration was performed. At this time, for comparison, the conventional ordinary portland cement (Comparative Example 5) and the low heat Portland cement (Comparative Example 4) specified in the KS standard were tested together. This microhydration heat test was carried out by measuring the cumulative heat of hydration for 72 hours at a temperature of 20 ℃ and 50% by weight of water / binder (W / B) using a TCC-26 device manufactured by Tokyo Rico, Japan, and the result It is shown in Figure 2 below.

As can be seen in FIG. 2 attached below, the ordinary portland cement (Comparative Example 5) and the low heat Portland cement (Comparative Example 4) exhibit a hydration heat of 200 J / g or more. In addition, the two-component binder (Comparative Example 3) in which only cement and blast furnace slag fine powder were mixed (Comparative Example 3) exhibited a hydration heat of about 180 J / g, which was higher than that of the binder in which bottom ash and fly ash were mixed. On the other hand, the use of mechanochemically treated samples (Examples 1-3 and Comparative Example 2) and general fly ash (Comparative Example 1) showed a hydration calorific value of 170 J / g or less, and was excellent in controlling the heat of hydration of concrete. It could be confirmed to exert.

Manufacturing example  3: Manufacture of concrete

Using the binder to prepare concrete at the conditions and content ratios as shown in Table 7 below:

Formulation Name Water / binder
(W / B) ratio
(%) Fine aggregate rate
(S / a,%) slump
(cm) Air
(%) Unit Weight (kg / m ³ ) water
(Water) Binder
(Binder) sand
(Sand) Pebble
(Gravel) Example 4 40.0 46.5 18.0 4.5 160 Example 1 400 783 915 Example 5 Example 2 785 917 Example 6 Example 3 784 916 Comparative Example 6 Comparative Example 1 782 913 Comparative Example 7 Comparative Example 2 787 919 Comparative Example 8 Comparative Example 3 792 925

And, the amount of slump and admixture of the concrete of Examples 4 to 6 and Comparative Examples 6 to 8 of Table 7 is shown in Figure 3 attached below.

As can be seen in FIG. 3 below, in the case of concrete workability, Examples 4 to 6 using a sample treated with mechanochemical by mixing bottom ash at 50% by weight or less, compared with a sample having a composition different from the present invention. Compared with Examples 6 to 8, it was confirmed that the amount of admixture for obtaining the same slump is reduced and shows excellent workability.

Test Example  3: compressive strength of concrete

In accordance with KS F 2405 "Test Method for Compressive Strength of Concrete", the strength expression characteristics of the binders included in the concrete prepared in Preparation Example 3 were evaluated, and the results are shown in FIG. 4 below.

As can be seen in Figure 4, in the case of Examples 4 to 6, as the content of the bottom ash increased initial strength was reduced, it was confirmed that excellent long-term strength expression. This is due to the pozzolanic reactivity of the surface-treated bottom ash, it can be seen that excellent performance in the durability of the concrete.

Test Example  4: durability evaluation of concrete

The salt shielding properties of the binders included in the concrete prepared in Preparation Example 3 were compared and evaluated in accordance with KS F 2771 “Chlorine ion penetration resistance using electrical conductivity”, and the results are shown in FIG. 5 below.

As can be seen in Figure 5, Comparative Example 8 containing a relatively large amount of fine slag fine powder initially shows excellent performance, but in the long-term age, Examples 4 to 6 in which the tissue is densified by the pozzolanic reaction It was confirmed that excellent salt shielding properties.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (8)

(a) 10-30 weight percent ash mixture comprising 5-50 weight percent bottom ash and 50-95 weight percent fly ash; (b) 30-50% by weight of blast furnace slag powder; And (c) 30-40% by weight of Portland cement.
The binder composition for concrete according to claim 1, wherein the ash mixture includes 25-50 wt% of bottom ash and 50-75 wt% of fly ash based on the total weight of the ash mixture.
The binder composition for concrete according to claim 1, wherein the ash mixture has a brain specific surface area of 6000-8000 cm ² / g.
The binder composition for concrete according to claim 1, wherein the ash mixture is mixed by mechanochemical treatment under a condition of applying physical energy of 50-150 KJ / s per unit volume of ash mixture (m ³ ).
The binder composition for concrete according to claim 1, wherein the ash mixture is mixed by grinding with a vibrating mill for 30-120 minutes and subjected to mechanochemical treatment.
4. The binder composition for concrete according to claim 3, wherein the ash mixture has a brain specific surface area of 6000-6300 cm ² / g.
The binder composition for concrete according to claim 1, wherein the composition comprises 20% by weight of ash mixture, 40-45% by weight of blast furnace slag powder and 35-40% by weight of Portland cement, based on the total weight of the composition. .
The binder composition for concrete according to claim 1, wherein the composition has a cumulative heat of hydration of 120-170 J / g after 3 days of age.

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