KR20160144058A - Ultra-high performance concrete for mixing micro basalt fiber and macro steel fiber, and manufacturing method for the same - Google Patents

Abstract

Provided are ultra-high performance concrete (UHPC) for mixing a micro basalt fiber and a macro steel fiber, and a manufacturing method thereof, capable of increasing initial crack strength and bending tensile strength by mixing the micro basalt fiber and the macro steel fiber into a binder during manufacture of the UHPC, and economically manufacturing the UHPC by mixing, not only the steel fiber, the steel fiber and the micro basalt fiber cheaper than the steel fiber together into the binder during the manufacture of the UHPC. The UHPC for mixing the micro basalt fiber and the macro steel fiber includes: a binder; the micro basalt fiber; the macro steel fiber; coarse aggregate; fine aggregate; water; and a superplasticizer.

Description

TECHNICAL FIELD [0001] The present invention relates to an ultra high performance concrete incorporating a micro-basalt fiber and a macro steel fiber, and a method of manufacturing the ultra high performance concrete.

The present invention relates to an ultra-high performance concrete, and more particularly, to a method of manufacturing an ultra-high performance concrete (UHPC) The present invention relates to an ultra high performance concrete in which a steel fiber (Macro Steel Fiber) is incorporated into a binder and a manufacturing method thereof.

With the development of construction technology, structures are gradually becoming higher, larger, and specialized. In recent years, interest in high-rise buildings and long bridges has been rising. As a result, concrete has evolved into ultra high strength and ultra high performance areas in order to reduce the weight of the concrete structure or to reduce the member cross section in the high strength concrete field to further secure the effective space.

In general, ultra-high-strength concrete or ultra-high-performance concrete means concrete with a compressive strength of 80 MPa or more, and is applied to skyscraper buildings and bridge bridges due to various advantages such as long-term conversation of structure span, reduction of vertical member section, improvement of durability, Is expected to increase.

In order to increase the compressive strength of such ultra high strength concrete or ultra high performance concrete, it is necessary to increase the amount of unit cement, which is the amount of binder composed of cement or cement and mineral admixture, And a fine aggregate composed of a certain amount of fine aggregate (S / a) and a coarse aggregate are mixed and manufactured using a mixer, which is a comparable device. At this time, since these materials do not rub against each other at a low water-binding ratio (W / B), a high performance water reducing agent is used to secure the fluidity required for concrete pouring at the time of construction. Such a high- have.

At this time, the required fluidity of the ultra-high-strength concrete or ultra-high-performance concrete has high fluidity and clear permeability so that the reinforcing bars and the like can be densely packed in the formwork without compaction or compaction, And the required homogeneity is ensured.

Here, the high-flowable concrete is also referred to as a self-filled high-flowable concrete and means a concrete having a very high flowability. The concrete having a slump flow higher than that of a slump flow of about 600 mm is referred to as a high- This technology is combined with ultra-high-strength concrete or ultra-high-performance concrete is manufactured.

In order to improve not only the compressive strength but also the fluidity and the durability, the ultra high strength concrete or the ultra high performance concrete is suitably selected as the mineral admixture such as the silica fume, the blast furnace slag, the fly ash and the limestone fine powder, The amount of unit cement is determined by composing the binder. The method and the manufacturing method of the binder are very important for ultra high strength concrete or ultra high performance concrete.

For example, the method of constructing ultrahigh-strength concrete or ultra-high-performance concrete is to mix minerals such as silica fume, blast furnace slag, fly ash, and limestone fine powder into cement with a binary or a mixture of two mineral materials And a ternary system in which a mixture of tungsten and tungsten is mixed with cement at a certain ratio.

This method is based on the pozzolanic reaction that slowly reacts with calcium hydroxide and mineral admixture caused by hydration of cement to form insoluble compounds. Concrete using these materials has advantages such as increased workability, bleeding reduction, long-term strength development, Is generally known to have.

 In addition, methods such as blast furnace slag fine powder, fly ash, and limestone fine powder are further pulverized to increase their powder degree to increase the pozzolanic reactivity.

However, when cement alone is used as a binder for ultrahigh strength concrete or ultra high performance concrete, the compressive strength is almost expressed at 28 days of age, and when the cement and mineral admixture are used together, And it is known that the projected compressive strength appears after about 90 days.

Therefore, depending on the kind of the admixture used, the timing of the manifestation of the strength differs. When two or more mineral admixtures are used together, the problem of the strength development may become more serious depending on the characteristics of the mineral admixture used.

In addition, when a mineral admixture is used, since the phenomenon that the strength is enhanced is based on the pozzolanic reaction to the long-term age, it is necessary to pay more attention to concrete curing.

Meanwhile, the method of manufacturing ultra-high-strength concrete or ultra-high-performance concrete is such that the unit water amount required to make 1 m 3 of concrete is set to about 140 to 160 kg / m 3 and the unit cement amount is adjusted so that the water- , A fine aggregate of 5 to 25 mm is formed of coarse aggregate by using steel sand or crushed sand of 5 mm or less as a fine aggregate with a fine aggregate ratio of 30 to 50% by weight and a constant fluidity (usually about 600 mm ) Based on the total amount of the polycarboxylic acid-based high-performance water reducing agent in an appropriate ratio.

However, since the water-binder ratio of the ultrahigh strength concrete or ultra high performance concrete is very low, the use amount of the high performance reducing agent is inevitably increased. When the high performance reducing agent is used in a large amount, the air amount in the concrete is increased, There are problems such as delay in expression and increase in manufacturing cost.

Of course, in order to improve the durability of ultrahigh strength concrete or ultra high performance concrete, concretely, concrete formulation design is recommended to carry out air amount of 4.5 wt% or more inside 1m3 of concrete in order to have resistance to freezing and thawing.

On the other hand, as a conventional technology relating to ultrahigh strength concrete or ultra high performance concrete, there has been proposed a method in which cement is added with silica fume, blast furnace Slag fine powder and anhydrous gypsum in a suitable ratio, and a low water-binder ratio. In Korean Registered Patent No. 10-622048, there has been disclosed a composite composition for metakaolin Has been disclosed in Korean Patent No. 10-873514, and a binder for ultrahigh strength concrete using silica sand as a filler has been disclosed in Korean Registered Patent No. 10-873514.

The conventional technology related to ultrahigh strength concrete or ultra high performance concrete is a method of increasing the level of compressive strength by using excellent pozzolanic reaction material such as silica fume. However, pozzolanic reaction materials such as silica fume have a limitation in increasing the amount of materials such as silica fume because they cause a decrease in the fluidity of the concrete.

Specifically, ultrahigh strength concrete or ultra high performance concrete is characterized by using a large amount of binder of fine powder and a very low water-binding ratio of 0.3 or less. As a result, the viscosity of the concrete is increased, and the fluidity of the concrete is decreased, resulting in a problem that the workability is lowered. In order to solve such a problem of deterioration in workability of concrete, a high-performance water reducing agent can be used in a large amount to ensure workability, but the manufacturing cost is increased rapidly. In addition, recently, high-performance water reducing agent technology has been rapidly developed, and thus, the production of ultrahigh strength concrete or ultra high performance concrete has been simplified. However, a large amount of high performance water reducing agent has problems such as not only an increase in manufacturing cost but also a delay in congealing.

In recent years, development and related researches on Ultra-High Performance Concrete (UHPC), which improves the performance of ordinary concrete, which is a traditional construction material, have been actively pursued as the size and frequency of natural disasters have increased along with urbanization It is progressing.

This ultra high performance concrete (UHPC) has a compressive strength of 150 MPa or more and is defined as concrete having a high binder content while using special aggregate so that brittle behavior does not appear through the incorporation of fiber.

This ultra high performance concrete (UHPC) also has a very low water / binder ratio (W / B), for example, a water / binder ratio (W / B) of 0.3 or less, And has excellent rheological properties using a high performance water reducing agent.

On the other hand, as a prior art, Korean Patent No. 10-1134459 discloses an invention entitled " Method for manufacturing concrete pavement using microfibers and macro fibers, concrete pavement using the same and concrete pavement construction method ".

Since the fibers mainly used for ultra high performance concrete (UHPC) are straight steel fibers having a diameter of 0.2 mm, it is considered that the improvement effect of tensile performance due to the incorporation of macro fiber and micro fiber is somewhat different So far, studies on the incorporation of macro fiber and micro fiber into ultra high performance concrete (UHPC) have been insufficient.

Korean Patent No. 10-1134459 filed on Dec. 10, 2009, entitled "Method of manufacturing concrete pavement using microfiber and macro fiber, method of constructing concrete pavement and concrete pavement using the same, Korean Patent No. 10-686350 filed on November 28, 2005, entitled "Ultra High Strength Concrete Composition" Korean Patent No. 10-698759 filed on August 24, 2006, entitled "Cement Binder Composition for Ultrahigh Strength Concrete and Method for Manufacturing the Same" Korean Patent No. 10-873514 filed on Sep. 3, 2007, entitled "Binder for Ultrahigh Strength Concrete and Method of Making Concrete Using the Same" Korean Patent No. 10-927377 filed on June 9, 2008, entitled "Method for producing high performance concrete"

The present invention has been made to solve the above problems and an object of the present invention is to provide a method of manufacturing ultra-high performance concrete (UHPC) by mixing micro basalt fiber and macro steel fiber with a binder The present invention is to provide an ultrahigh performance concrete containing micro-basalt fiber and macro-steel fiber, which can increase the initial crack strength and flexural tensile strength by incorporating the micro-basalt fiber and the macro steel fiber into a binder.

Another object of the present invention is to provide a method of manufacturing a high performance concrete (UHPC) economically by incorporating low cost micro basalt fiber together with a steel fiber in a high performance concrete (UHPC) without incorporating only a steel fiber into a binder The present invention relates to an ultra high performance concrete containing micro-basalt fiber and macro-steel fiber, and a manufacturing method thereof.

As a means for achieving the above technical object, the ultra high-performance concrete incorporating micro-basalt fiber and macro steel fiber according to the present invention is formed by mixing cement and fly ash, A binder (B) mixed with negative fly ash; 1 to 5 parts by weight of micro basalt fiber based on 100 parts by weight of cement; 1 to 5 parts by weight of macro-steel fiber based on 100 parts by weight of cement; 65 to 85 parts by weight of coarse aggregate based on 100 parts by weight of cement; 45 to 55 parts by weight of fine aggregate based on 100 parts by weight of cement so that the fine aggregate ratio (S / a), which is the volume ratio of fine aggregate to total aggregate (fine aggregate + coarse aggregate) volume, is smaller than 0.4; 40 to 60 parts by weight of water (W) based on 100 parts by weight of the cement so that the ratio (W / B) of the water-binder is 0.3 or less; And 4 to 7 parts by weight of a high-performance water reducing agent based on 100 parts by weight of cement, wherein the micro-basalt fiber and the macro-steel fiber are mixed in the binder (B) at a mixing ratio of 1: 1 to 1: 3 do.

Preferably, the micro-basalt fiber has a diameter of 0.05 mm or less and a length of 15 mm or less, and the macro-steel fiber is a brass-coated straight fiber having a diameter of 0.2 mm or more and a length of 20 mm to 30 mm.

Here, the micro-basalt fiber has a tensile strength of 2,500 MPa, a Young's Modulus of 90 GPa, and a density of 2.46 g / cm 3, which can increase the initial crack strength and flexural tensile strength of the concrete.

Here, the fine aggregate ratio (S / a) is determined to determine the flowability of the concrete and is less than 0.4 (40%) so as to reduce the amount of the high-performance water reducing agent used.

Here, the high performance water reducing agent uses a polycarboxylic acid system, and the amount of the high performance water reducing agent can be adjusted according to the fluidity.

The binder (B) is formed by additionally mixing silica fume and blast furnace slag fine powder in the cement and fly ash. The cement is blended with 6 to 20 parts by weight of silica fume, 22 to 35 parts by weight of blast furnace Slag fine powder and 22 to 35 parts by weight of fly ash.

In another aspect of the present invention, there is provided a method of manufacturing an ultra high performance concrete comprising micro-basalt fiber and macro steel fiber according to the present invention, comprising the steps of: a) Preparing 40 to 60 parts by weight of water (W); b) preparing a binder (B) having 22 to 35 parts by weight of fly ash mixed with 100 parts by weight of cement; c) mixing 1 to 5 parts by weight of micro basalt fiber and 1 to 5 parts by weight of macro steel fiber with 100 parts by weight of cement; d) mixing 40 to 60 parts by weight of water (W) based on 100 parts by weight of the cement so that the ratio (W / B) of the water-binding material is 0.3 or less; e) preparing a mixed water by mixing 4 to 7 parts by weight of a high-performance water reducing agent with 100 parts by weight of the cement; f) selecting 45 to 55 parts by weight of the fine aggregate and 65 to 85 parts by weight of the coarse aggregate with 100 parts by weight of the cement so that the fine aggregate fraction (S / a) is smaller than 0.4; And g) forming ultrahigh performance concrete (UHPC) by mixing the binder, micro-basalt fiber, macro-steel fiber, fine aggregate, coarse aggregate and blend water, wherein the micro-basalt fiber and the macro- Is mixed with the binder (B) at a mixing ratio of 1: 1 to 1: 3.

According to the present invention, when a micro-basalt fiber and a macro-steel fiber are incorporated into a binder in the manufacture of Ultra-High Performance Concrete (UHPC), the initial crack strength and flexural strength The strength can be increased.

According to the present invention, high-performance concrete (UHPC) can be produced economically by mixing micro-basalt fibers, which are inexpensive compared to steel fibers, without incorporating only steel fibers into a binder in the production of high performance concrete (UHPC).

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view illustrating the construction of a super high-performance concrete incorporating micro-basalt fiber and macro steel fiber according to an embodiment of the present invention.
FIG. 2 is a view illustrating a composition ratio of ultra-high-performance concrete incorporating micro-basalt fiber and macro-steel fiber according to an embodiment of the present invention.
FIG. 3 is a flowchart illustrating an operation of a method for manufacturing ultra-high-performance concrete incorporating micro-basalt fiber and macro steel fiber according to an embodiment of the present invention.
4 is a view illustrating mixing of micro-basalt fiber and ultra high-performance concrete mixed with macro-steel fiber according to an embodiment of the present invention.
FIG. 5 is a graph showing the characteristics of micro-basalt fiber and macro-steel fiber in ultra-high-performance concrete incorporating micro-basalt fiber and macro-steel fiber according to an embodiment of the present invention.
6A and 6B are diagrams showing initial crack strength and bending tensile strength test results of ultra high-performance concrete incorporating micro-basalt fiber and macro-steel fiber according to an embodiment of the present invention, respectively.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

[Ultra-high-performance concrete incorporating micro-basalt fiber and macro-steel fiber]

FIG. 1 is a view illustrating the construction of ultra-high-performance concrete incorporating micro-basalt fiber and macro steel fiber according to an embodiment of the present invention. FIG. 2 is a cross- High-performance concrete.

1 and 2, an ultra-high performance concrete 100 incorporating micro-basalt fiber and macro steel fiber according to an embodiment of the present invention includes a binder (B) 110, a fine aggregate 120, a coarse aggregate 130, (W) 140, a high-performance water reducing agent 150, a micro-basalt fiber 160 and a macro-steel fiber 170. The binder 110 is composed of cement 111, silica fume 112, blast- (113) and fly ash (114) are mixed and formed.

2, a binder material (B) 110 includes cement 111 and fly ash 114 in an ultra-high performance concrete 100 incorporating micro-basalt fiber and macro steel fiber according to an embodiment of the present invention. And the fly ash 114 is mixed with 22 to 35 parts by weight of the cement 111 as 100 parts by weight. The binder material B 110 is formed by further mixing silica fume 112 and blast furnace slag powder 113 with the cement 111 and the fly ash 114. The cement 111 is mixed with 100 parts by weight A mixture of 6 to 20 parts by weight of silica fume 112, 22 to 35 parts by weight of blast furnace slag 113 and 22 to 35 parts by weight of fly ash 114 may be blended.

1 to 5 parts by weight of Micro Basalt Fiber 160 is mixed with 100 parts by weight of cement 111 and Macro Steel Fiber 170 is mixed with 100 parts by weight of cement 111 1 to 5 parts by weight are incorporated. At this time, it is preferable that the micro-basalt fiber 160 and the macro steel fiber 170 are mixed in the binder (B) 110 at a mixing ratio of 1: 1 to 1: 3. For example, the micro-basalt fiber 160 has a diameter of 0.05 mm or less and a length of 15 mm or less. The macro-steel fiber 170 is a brass-coated straight fiber having a diameter of 0.2 mm or more, 30 mm. At this time, the micro-basalt fiber 160 has a tensile strength of 2,500 MPa, a Young's Modulus of 90 GPa, and a density of 2.46 g / cm 3, which can increase the initial crack strength and flexural tensile strength of concrete .

 The coarse aggregate 130 is mixed with 65 to 85 parts by weight based on 100 parts by weight of the cement 111. The fine aggregate 120 is mixed with the fine aggregate 130 having a volume ratio of the fine aggregate 120 to the total aggregate (fine aggregate + coarse aggregate) 45 to 55 parts by weight based on 100 parts by weight of the cement (111) are mixed so that the ratio (S / a) is less than 0.4. At this time, the fine aggregate ratio (S / a) is preferably less than 0.4 (40%) to determine the flowability of the concrete and reduce the amount of the high-performance water reducing agent 150 used.

Water (W: 140) is incorporated in an amount of 40 to 60 parts by weight based on 100 parts by weight of the cement (111) so that the ratio (W / B) of the water-binding material is 0.3 or less.

The high performance water reducing agent 150 is mixed with 4 to 7 parts by weight based on 100 parts by weight of the cement (111). For example, the high performance water reducing agent 150 uses a polycarboxylic acid system, and the amount of the high performance water reducing agent 150 can be adjusted according to fluidity. That is, the high-performance water reducing agent 150 is based on the use of a polycarboxylic acid-based system, and the amount to be used can be appropriately determined according to the water-binding ratio, the kind of the binder 110,

More specifically, although the cement 111 of the binder 110 can usually use Portland cement, crude steel portland cement, mixed cement, etc., it is preferable to use Portland cement (OPC) usually in terms of economy.

The silica fume (112) of the binder (110) is formed of spherical particles, so that the rheology of the cement paste can be improved by reducing the friction, and the voids between the cement particles It is possible to suppress the filling and improve the strength. In addition, the silica fume 112 enhances strength and water tightness by a pozzolanic reaction that reacts with calcium hydroxide generated at hydration of the cement 111, so that the performance of the ultra high performance concrete 100 according to the embodiment of the present invention Can be improved. For example, the silica fume 112 may be used in an amount of about 6 to about 20 parts by weight based on 100 parts by weight of the cement (111) so as to satisfy KS F 2567 (Korean Industrial Standard for silica fume for concrete) desirable.

More specifically, the silica fume 112 is a very fine pozzolanic material produced as a by-product in the process of producing silicon metal or ferro silicon in an electric arc furnace, Silicon, and is also referred to as condensed silica fume or microsilica. Such silica fumes are classified into a powder form (undensified type or as-produced type) produced in the form recovered in the recovery process according to a material handling method, a granular form (condensed with a constant pressure) and a slurry Type). For example, the unit mass per unit product type of silica fume is 450 kg / m 3 or less for undensified type, 700 kg / m 3 or less for granular type, 1350 to 450 kg / m 3 for slurry type, .

In addition to the cement 111 and the silica fume 112, the binder 110 may have a fly ash 114 having a powdery degree of 2,000 to 4,000 cm 2 / g and a powdery degree of 3,000 to 5,000 cm 2 / g Wherein the fly ash 114 and the blast furnace slag 113 are composed of a mixture ratio of 90:10 to 30:70 respectively and the blast furnace slag 113 has a hydration reaction And the glass coating of the fly ash 114 is destroyed at a temperature of 5 to 90 캜 by the polymerization reaction. For example, the mixing ratio of the fly ash 114 and the blast furnace slag 113 can be adjusted according to workability and initial strength. When the mixing ratio of the fly ash 114 and the blast furnace slag 113 is 50:50 , The ultra high performance concrete may have a compressive strength of 120 MPa or more.

When the powdery degree of the fly ash (114) is less than 2,000 cm 2 / g and the blast furnace slag (113) has a powdery degree of less than 3,000 cm 2 / g, the reactivity is low, which is disadvantageous in terms of strength development. If the powdery degree of the blast furnace slag 113 exceeds 4,000 cm2 / g and the powdery degree of the blast furnace slag 113 exceeds 5,000 cm2 / g, the reactivity is large, but the powder generated in the thermal power plant or the steel mill becomes larger, Or classification, which may reduce economic efficiency.

The fly ash 114 and the blast furnace slag 113 may be blended at a weight ratio of, for example, 90:10 to 30:70, wherein the weight ratio of the fly ash 114 is 90% (The blast furnace slag weight ratio is less than 10%), the workability is secured. However, there is a problem that the compressive strength is significantly lowered by room temperature curing, and the weight ratio of the fly ash 114 is less than 30% When the weight ratio of slag is more than 70%, the compressive strength can be secured at high strength, but the workability is not ensured.

The workability and initial strength can be adjusted by adjusting the mixing ratio of the fly ash 114 and the blast furnace slag 113 and the fly ash 114 and the blast furnace slag 113 can be manufactured in order to manufacture an ultra- In a ratio of about 1: 1 is most effective. That is, it is possible to manufacture an ultra-high-performance concrete which can easily adjust the fluidity and strength according to the user's demand according to the mixing ratio of the fly ash 114 and the blast furnace slag 113.

Also, the glass material of the fly ash 114 is broken at the room temperature of 5 to 40 ° C by hydration reaction and polymerization reaction of the blast furnace slag 113. That is, when the fly ash (114) is used, a glassy coating is formed. Therefore, in order to accelerate the reaction of the fly ash (114) by breaking the glass coating, a very high alkali environment of pH 13 or higher, Other methods are needed. However, since the blast furnace slag 113 contains a large amount of SiO ₂ , Al ₂ O ₃ , particularly CaO (generally containing 40% or more of blast furnace slag), the hydration reaction and the polymerization reaction are carried out at room temperature, Even if a glass coat of the fly ash 114 is destroyed and a large amount of the fly ash 114 is mixed, a polymerization reaction occurs at room temperature and the strength can be largely expressed.

Accordingly, the ultra-high performance concrete 100 incorporating the micro-basalt fiber and the macro steel fiber according to the embodiment of the present invention can be manufactured by mixing the micro basalt fiber and the macro steel fiber into the binder (UHPC) can be manufactured economically by incorporating low-cost micro-basalt fibers together with steel fibers without incorporating only existing steel fibers into a binder. have.

[Manufacturing Method of Ultra High Performance Concrete Containing Micro Basalt Fiber and Macro Steel Fiber]

FIG. 3 is a flowchart illustrating an operation of a method for manufacturing ultra-high-performance concrete incorporating micro-basalt fiber and macro steel fiber according to an embodiment of the present invention.

Referring to FIG. 3, a method of manufacturing ultra-high performance concrete incorporating micro-basalt fiber and macro steel fiber according to an embodiment of the present invention includes: 40 to 60 parts by weight of water (W: 140) is prepared as a part (S110).

Next, a binder (B: 110) in which 22 to 35 parts by weight of fly ash (114) is mixed with 100 parts by weight of cement (111) is prepared (S120). The binder (B) 110 is formed by further mixing silica fume 112 and blast furnace slag fine powder 113 with the cement 111 and fly ash 114. The cement 111 is mixed with 100 parts by weight It is preferable that 6 to 20 parts by weight of silica fume (112), 22 to 35 parts by weight of blast furnace slag fine powder (113) and 22 to 35 parts by weight of fly ash (114) are mixed. At this time, the mixture constituting the binder 110 is mixed at a speed of 20 rpm to 40 rpm for 5 minutes to 7 minutes.

Next, 1 to 5 parts by weight of the micro basalt fiber 160 and 1 to 5 parts by weight of the macro steel fiber 170 are mixed with 100 parts by weight of the cement 111 (S130). The micro-basalt fiber 160 and the macro steel fiber 170 are incorporated into the binder material B at a mixing ratio of 1: 1 to 1: 3. For example, the micro- Diameter of not more than 0.05 mm and a length of not more than 15 mm, and the macro steel fiber 170 is a brass-coated straight fiber having a diameter of 0.2 mm or more and a length of 20 mm to 30 mm. At this time, the micro-basalt fiber 160 has a tensile strength of 2,500 MPa, a Young's Modulus of 90 GPa, and a density of 2.46 g / cm 3, which can increase the initial crack strength and flexural tensile strength of concrete .

Next, 40 to 60 parts by weight of water (W: 140) is blended (S140) based on 100 parts by weight of the cement (111) so that the ratio (W / B) of the water-binding material is 0.3 or less. At this time, the mixture is mixed for 4 minutes to 10 minutes at a speed of 80 rpm to 120 rpm, and then mixed for 1 minute to 3 minutes at a speed of 40 rpm to 60 rpm.

Next, mixing water is prepared by mixing 4 to 7 parts by weight of the high-performance water reducing agent 150 with 100 parts by weight of the cement 111 (S150). For example, the high performance water reducing agent 150 uses a polycarboxylic acid system, and the amount of the high performance water reducing agent 150 can be adjusted according to fluidity.

Next, 45 to 55 parts by weight of the fine aggregate 120 and 65 to 85 parts by weight of the coarse aggregate 130 are selected using 100 parts by weight of the cement 111 so that the fine aggregate ratio S / a is smaller than 0.4 ). That is, the fine aggregate ratio (S / a) is preferably less than 0.4 (40%) to determine the flowability of the concrete and reduce the amount of the high-performance water reducing agent 150 used.

Ultra high performance concrete (UHPC) 100 is formed by mixing the binder 110, the micro basalt fiber 160, the macro steel fiber 170, the fine aggregate 120, the coarse aggregate 130, and the mixed water S170).

[Experimental Example]

FIG. 4 is a view illustrating blending of micro-basalt fiber and ultra-high-performance concrete mixed with macro-steel fiber according to an embodiment of the present invention. FIG. 5 is a view illustrating mixing of micro-basalt fiber and macro- This figure shows the characteristics of micro-basalt fiber and macro-steel fiber in ultra high-performance concrete.

As shown in FIG. 4, Comparative Example 1 shows ultra-high-performance concrete without using micro-basalt fiber and macro-steel fiber, Comparative Example 12 shows ultra-high-performance concrete using only macro-steel fiber, High performance concrete using both fiber and macro steel fiber.

As shown in FIG. 4, cement 111, silica fume 112, blast furnace slag fine powder 113, and silica fine powder 113 are mixed with micro-basalt fiber and macro steel fiber according to an embodiment of the present invention, The micro-basalt fiber 160, the macro-steel fiber 170, the fine aggregate 120 and the coarse aggregate 130 in which the fly ash 114 is mixed is put into a mixer and is fed to the mixer at a speed of 20 rpm to 40 rpm for 5 minutes The water 140 and the high-performance water reducing agent 150 are added thereto, and the mixture is mixed at a speed of 80 rpm to 120 rpm for 4 minutes to 10 minutes. Thereafter, the mixture is further mixed at a speed of 40 rpm to 60 rpm for 1 minute to 3 minutes And the initial crack strength and flexural tensile strength were measured, respectively, and are shown in FIGS. 6A and 6B, respectively.

The ultrahigh performance concrete 100 incorporating the micro-basalt fiber and the macro steel fiber according to the embodiment of the present invention can be manufactured by mixing the macro steel fiber 170 and the micro basalt fiber 160 in order to improve the tensile deformation performance of the ultra high performance concrete (UHPC) For example, by mixing the brass-coated macro-steel fiber 170 and the basaltic micro-basalt fiber 160 with a diameter of 0.2 mm so that the micro-basalt fiber 160 is free of macro- The tensile strength and toughness can be increased as a result.

Specifically, Basalt Fiber (BF) is a fiber used for industrial purposes and is a pure inorganic fiber extracted by melting basalt, which is a result of volcanic activity, at 1,500 ° C. These basalt fibers are natural fibers made of basalt as the main raw material, they are environmentally friendly, have no toxicity, and can be produced at low cost and energy because they are made of cheap and rich domestic raw materials. In addition, since these basalt fibers are known to have abrasion resistance, erosion resistance, light weight and high strength properties as well as excellent fire retardancy, heat insulation, heat resistance, soundproofing and sound absorption performance as compared with existing fibers in physical properties, have.

Since such basalt fibers are dominated by glass fibers and carbon fibers compared to basalt fibers, they have not been researched and commercialized in many areas because they occupy most of the textile market. However, industrial fibers If the environment regulations of the basalt fiber are increased and the mass production facilities and environment of the basalt fiber are equipped, the production capacity and usage of the basalt fiber will increase because it is very likely to be used as a highly functional material for the industrial structure which is not only price competitive, .

The ultra-high-performance concrete (100) containing micro-basalt fiber and macro-steel fiber according to the embodiment of the present invention can be used for the initial cracking of ultra high performance concrete (UHPC) by using basalt fiber unlike the existing steel fiber and organic fiber The reason why the strength and flexural tensile strength can be increased is because the basalt fiber having a similar chemical composition strongly bonds chemically with the matrix and has high adhesion strength.

In other words, the high mechanical strength of the ultra-high-performance concrete 100 can be secured due to the high adhesion strength of the micro-basalt fiber 160, and the economical efficiency can be secured because it is cheaper than the conventional macro steel fiber 160.

5, the micro-basalt fiber 160 has a diameter of 0.05 mm or less and a length of 15 mm or less, and the macro steel fiber 170 is a brass-coated straight fiber having a diameter of 0.2 mm or more and a length of It is preferably 20 mm to 30 mm. At this time, the micro-basalt fiber 160 has a tensile strength of 2,500 MPa, a Young's Modulus of 90 GPa, and a density of 2.46 g / cm 3, which can increase the initial crack strength and flexural tensile strength of concrete .

6A and 6B are diagrams showing initial crack strength and bending tensile strength test results of ultra high-performance concrete incorporating micro-basalt fiber and macro-steel fiber according to an embodiment of the present invention, respectively.

As described above, since the basalt fiber is an inorganic material, it has physical and chemical properties similar to those of materials used in ultrahigh performance concrete (UHPC), so that the thermal expansion coefficient and the like are similar, and the adhesion strength can be improved. As a result, the initial tensile crack strength and flexural tensile strength of the ultrahigh performance concrete 100 using the macro steel fiber 170 and the micro basalt fiber 160, compared with the UHPC using only the conventional steel fiber, As shown in FIG. 6B, it can be seen that 18% is improved and 3% is improved as shown in FIG. 6B.

As a result, according to the embodiment of the present invention, when a micro-basalt fiber and a macro steel fiber are incorporated into a binder in the manufacture of Ultra-High Performance Concrete (UHPC) The crack strength and the bending tensile strength can be increased. In addition, high-performance concrete (UHPC) can be economically manufactured by incorporating low-cost micro-basalt fibers together with steel fibers without incorporating only steel fibers into a binder during the manufacture of high-performance concrete (UHPC).

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: Ultra High Performance Concrete (UHPC)
110: binder (Binder: B)
111: Cement
112: Silica Fume
113: Blast furnace slag fine powder (BS)
114: fly ash (FA)
120: Fine Aggregate
130: coarse aggregate
140: Water (W)
150: High performance water reducing agent
160: Micro Basalt Fiber
170: Macro Steel Fiber

Claims (12)

A binder (B: 110) in which cement (111) and fly ash (114) are blended and mixed with fly ash (114) in an amount of 22 to 35 parts by weight based on 100 parts by weight of the cement (111);
1 to 5 parts by weight of Micro Basalt Fiber (160) based on 100 parts by weight of cement (111);
1 to 5 parts by weight of Macro Steel Fiber (170) based on 100 parts by weight of cement (111);
65 to 85 parts by weight of coarse aggregate (130) based on 100 parts by weight of cement (111);
45 to 55 parts by weight of the fine aggregate 120 based on 100 parts by weight of the cement 111 so that the fine aggregate ratio S / a, which is the volume ratio of the fine aggregate 120 to the total aggregate volume (fine aggregate + coarse aggregate) ;
40 to 60 parts by weight of water (W: 140) based on 100 parts by weight of the cement (111) so that the ratio (W / B) of the water-binder is 0.3 or less; And
4 to 7 parts by weight of the high-performance water reducing agent 150 based on 100 parts by weight of the cement (111)
, ≪ / RTI &
Characterized in that the micro-basalt fiber (160) and the macro steel fiber (170) are mixed in the binder (B) (110) at a mixing ratio of 1: 1 to 1: 3. concrete. The method according to claim 1,
The micro-basalt fiber 160 has a diameter of 0.05 mm or less and a length of 15 mm or less. The macro-steel fiber 170 is a brass-coated straight fiber having a diameter of 0.2 mm or more and a length of 20 mm to 30 mm Ultra-high-performance concrete incorporating micro-basalt fiber and macro-steel fiber. 3. The method of claim 2,
The micro-basalt fiber 160 has a tensile strength of 2,500 MPa, a Young's Modulus of 90 GPa, and a density of 2.46 g / cm 3 to increase the initial crack strength and flexural tensile strength of the concrete Ultra High Performance Concrete Containing Micro Basalt Fiber and Macro Steel Fiber. The method according to claim 1,
(S / a) is less than 0.4 (40%) to determine the flowability of the concrete and to reduce the amount of the high performance water reducing agent (150). The micro-basalt fiber and the macro- concrete. The method according to claim 1,
Wherein the high-performance water reducing agent (150) is a polycarboxylic acid based material and the amount of the high-performance water reducing agent (150) is adjusted according to fluidity. The method according to claim 1,
The binder (B) 110 is formed by further mixing silica fume 112 and blast furnace slag fine powder 113 with the cement 111 and fly ash 114. The cement 111 is mixed with 100 parts by weight , 6 to 20 parts by weight of silica fume (112), 22 to 35 parts by weight of blast furnace slag fine powder (113) and 22 to 35 parts by weight of fly ash (114) Ultra high performance concrete. a) preparing water (W: 140) in an amount of 40 to 60 parts by weight based on 100 parts by weight of the cement (111) corresponding to the unit water amount of the ultra high performance concrete (100);
b) preparing a binder (B: 110) in which 22 to 35 parts by weight of fly ash (114) is mixed with 100 parts by weight of cement (111);
c) mixing 1 to 5 parts by weight of micro basalt fiber (160) and 1 to 5 parts by weight of macro steel fiber (170) with 100 parts by weight of cement (111);
d) mixing 40 to 60 parts by weight of water (W: 140) based on 100 parts by weight of cement (111) so that the ratio of water-binding material (W / B) is 0.3 or less;
e) preparing 4 to 7 parts by weight of a high-performance water reducing agent (150) with 100 parts by weight of the cement (111) to prepare a blended water;
f) selecting 45 to 55 parts by weight of the fine aggregate 120 and 65 to 85 parts by weight of the coarse aggregate 130 with 100 parts by weight of the cement 111 so that the fine aggregate ratio S / a is smaller than 0.4; And
g) forming ultrahigh performance concrete (UHPC: 100) by mixing the binder 110, the micro basalt fiber 160, the macro steel fiber 170, the fine aggregate 120, the coarse aggregate 130,
, ≪ / RTI &
The micro-basalt fiber (160) and the macro-steel fiber (170) are mixed into the binder (B) (110) at a mixing ratio of 1: 1 to 1: A method for producing ultra high performance concrete admixed. 8. The method of claim 7,
The micro-basalt fiber 160 in step c) has a diameter of 0.05 mm or less and a length of 15 mm or less. The macro-steel fiber 170 is a brass-coated straight fiber having a diameter of 0.2 mm or more, Wherein the micro-basalt fiber and the macro-steel fiber are mixed. 9. The method of claim 8,
The micro-basalt fiber 160 has a tensile strength of 2,500 MPa, a Young's Modulus of 90 GPa, and a density of 2.46 g / cm 3 to increase the initial crack strength and flexural tensile strength of the concrete A method of manufacturing ultra - high - performance concrete incorporating micro - basalt fiber and macro - steel fiber. 8. The method of claim 7,
Wherein the fine aggregate ratio S / a of the step f) is less than 0.4 (40%) to determine the flowability of the concrete and reduce the amount of the high-performance water reducing agent 150 used. A method for producing ultra high performance concrete admixed. 8. The method of claim 7,
Wherein the high performance water reducing agent 150 in the step d) is a polycarboxylic acid based system and the amount of the high performance water reducing agent 150 is controlled according to fluidity. . 8. The method of claim 7,
The binder (B) 110 in the step b) is further formed by mixing the cement 111 and the fly ash 114 with the silica fume 112 and the blast furnace slag fine powder 113, Wherein micro-basalt fibers and macro-fibers are mixed with 6 to 20 parts by weight of silica fume (112), 22 to 35 parts by weight of blast furnace slag fine powder (113) and 22 to 35 parts by weight of fly ash, A manufacturing method of ultra high performance concrete containing steel fiber.

Images