KR20190050409A - Ultra high performance concrete composite having separated aggregate of 5㎜ class, and ultra high performance concrete sleeper for railroad using the same - Google Patents

Abstract

Provided are an ultra-high performance concrete composition having a separated aggregate of 5 mm class and an ultra-high performance concrete sleeper for a railway produced by using the same. When ultra-high concrete (UHPC) is produced, at least one of dolomite, basalt, limestone, and granite is selected and included as a separated aggregate of 5 mm class, thereby reducing manufacturing costs of the UHPC and enabling excellent physical properties such as tensile strength and fluidity to be maintained. In addition, when a UHPC composition is used, it is possible to reduce a size of a cross section of a sleeper and reduce an amount of a reinforcing material, for example, an amount of PC steel and reinforcing steel, and improve abrasion resistance. Moreover, it is not necessary to conduct compaction on the sleeper as the UHPC composition has high fluidity, and the sleeper can be demolded from a mold after being cured at a general outside temperature within 24 hours or less.

Description

TECHNICAL FIELD [0001] The present invention relates to a high-performance concrete composition having a 5-mm-class aggregate aggregate and an ultra-high performance concrete sleeper for railway,

The present invention relates to an ultra high performance concrete composition and a railway sleeper. More particularly, the present invention relates to an ultra high performance concrete (UHPC) High-performance concrete sleeper for railway, and an ultra-high-performance concrete sleeper for railway manufactured using the same.

Typically, a prestressed concrete sleeper (PSC sleeper) is a sleeper made of high-strength concrete, PC steel wire, or PC steel rods, which disperses the train load transmitted from the rail downward and maintains the rail position and gauge precisely Is the core component of the railway track.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a photograph illustrating a PSC sleeper applied on a conventional gravel surface.

As shown in Fig. 1, a typical PSC sleeper can be applied on a gravel road of a ground cross section, and it is important that such a PSC sleeper is designed and manufactured so as to stably support vertical and lateral train loads, Since it is an orbit component exposed to a railway track, fatigue, crack resistance and environmental resistance should be guaranteed.

Generally, the concrete constituting material used for the production of such PSC sleepers includes three kinds of cement, 20 mm thick coarse aggregate, sand, admixture and compound water, and focuses on early strength development. It is not being used.

In addition, the larger the cross section of the PSC sleeper, the better the load resistance performance. However, the PSC sleeper composition, the track laying workability, the maintainability (for example, the work of track equipment such as tamping, It is a reality that it can not raise cross section because it falls off. In addition, when a gravel track is installed in the tunnel section, it is necessary to lower the sleeping height in order to secure the minimum road surface thickness. Otherwise, the size of the cross section of the tunnel increases, resulting in an increase in overall orbital / civil engineering costs.

Since PSC sleeper design tendency is to distribute the train load more widely distributed to the gravel road and roadbed to reduce the track misalignment and bedrock settlement, it is desirable to increase the width of the PSC sleeper but to reduce the height of the rail seat portion and the mid- Design is very important. In other words, the sleepers should be designed and manufactured at a level that is easy to manufacture and handle, guarantees the load resistance performance, and does not cause any problems in equipment work and manpower maintenance.

Generally, other reinforcements are not applied to the PSC sleepers except for the PC strand or PC steel bar. In this case, if a prestress force is applied to the ends of the PSC sleepers, it may cause splitting cracks between the strands or between the steel rods and the concrete interface, and when the repeated load is applied to the sleepers, the crack width increases And it extends to the surface of the sleepers, which ultimately leads to the sleeper breakage.

In addition, when a sleeper is manufactured using a PC steel bar, crack resistance may not be secured unless a reinforcement material of the host steel reinforcing bar concept is applied. Therefore, in the case of the sleepers to which the recently improved design technique is applied, reinforcement bars of the reinforcing bars and the stirrups are additionally disposed at the time of manufacturing. Of course, the application of the reinforcing concept reinforcing bars may be advantageous in terms of improving the load-resisting performance and durability of the sleepers, but the performance when the reinforcement is applied without applying the reinforcing material is increased It is necessary to apply a concrete composition which can be expressed.

2A and 2B are photographs showing that abrasion occurs on the rail seating surface according to the related art. FIG. 2A shows wear on the rail seating surface of the railroad sleeper, FIG. 2B shows the wear on the rail shown in FIG. This is a photograph specifically shown.

As shown in FIGS. 2A and 2B, the rail seat wear of the railroad sleepers is related to vertical load, rail load characteristics, and longitudinal load according to rail extension and contraction when the railroad car is operated under vertical load, lateral load, longitudinal load, . When the vertical load of the railway vehicle is transmitted to the rail pad through the rail, the length of the rail pad increases due to the Poisson effect and the height of the rail pad decreases. As a result, friction between the rail pad and the railway sleeping rail is generated. The railway sleeper rail seating surface may be worn.

In addition, the lateral load caused by the train motion can be applied to the rail during the operation of the railway vehicle, and the load can be applied to the rail in the longitudinal direction due to the running of the railway vehicle (especially starting and braking) When a directional load is applied, rail-to-rail friction between rail pads and railway sleepers may occur, which can lead to rail seat wear of railway sleepers, as shown in Figs. 2A and 2B.

Also, as the railway vehicle becomes heavier, the wear on the rail seat surface tends to increase. In this way, when the rails seating surface of a railroad sleeper is worn, the height of the railroad sleeper is reduced, which means that the load resistance performance (flexural strength and fatigue durability) is reduced. When the wear depth is continuously increased, It may lead to flexural cracks in the rail seating surface or fatigue failure due to an increase in the number of passing tonnage. Therefore, it can be said that the suppression or reduction of concrete wear is very important in securing the design life of the railway sleepers when friction with rail pads due to external force acts.

On the other hand, Ultra High Performance Concrete (UHPC) is a material of interest worldwide as a high density matrix structure having a very high compression strength of about 130 MPa, high ductility, impact resistance and high durability.

However, the materials that make up this ultra high performance concrete (UHPC) are not only energy consuming materials but also high carbon dioxide emissions, which is a construction material that is adversely affecting the environment. In particular, portland cement, one of the components of ultra high performance concrete (UHPC), has been reported to produce about 1.6 billion tons per year, accounting for 7% of total carbon dioxide emissions.

Silica powder and Silica Sand are very expensive materials compared to ordinary concrete materials among materials that make up ultra high performance concrete (UHPC). Therefore, the use of expensive ultra high performance concrete (UHPC) is limited to a part of a structure, and currently, studies for replacing silica fine powder and silica sand with low cost materials are being actively carried out.

For example, Natural Pozzolana, Fly ash, Limestone Powder, Cement Kiln Dust, Pulverized Steel Slag, and the like can be used as low-cost materials such as silica fume Silica fume) and UHPC substituted with silica sand have been disclosed, and environmentally friendly UHPC formulations in which expensive silica sand has been replaced by natural sand has been disclosed.

3 is a view schematically showing an ultra high-performance concrete according to the prior art.

3, an ultra-high-performance concrete 10 according to the related art is made of a cement 11, a binder made of silica fume 12 and a silica powder 13, Water: 14, superplasticizer 15, reinforcing fiber 16, and aggregate 17. At this time, the colloidal fluidizer 15 may be a high-performance water reducing agent, and the reinforcing fiber 16 may be a steel fiber. In particular, the ratio W / B of the water- , It is also known that a part of the cement 11 can be replaced with a blast furnace slag fine powder (GGBFS).

However, in the case of the ultra-high-performance concrete 10 according to the related art, there is a problem that performance is lowered when the material is replaced with a low-cost material.

4 (a) is a plan view, Fig. 4 (b) is a front view, and Fig. 4 (c) is a plan view of a conventional concrete sleeper, And Fig. 4 (d) is a cross-sectional view of the sleeper.

As shown in FIG. 4, the conventional type of concrete sleepers is a PSC sleepers utilizing ultra high performance concrete (UHPC) composition. In the case of the standard type, the fck is given as 60 MPa.

4 shows a steel bar, 2 denotes a fixing portion reinforcing steel bar, 3 denotes a rail seat portion, and 4 denotes a tread middle portion. Specifically, the diameter of the steel bar is 11 mm, Are each disposed at both ends with a diameter of 10 mm, and the section height of the rail seat portion is 195 mm as shown in Fig. 4 (b), and the section height of the railroad tread is given as 180 mm.

5 (a) is a plan view, Fig. 5 (b) is a reference view of a steel bar, and Fig. 5 (c) is a plan view showing a slope type concrete tread as a prestressed wide- 5 is a front view of the tension reinforcing steel bar reference, Fig. 5 (d) is a cross-sectional view of the rail seat, and Fig. 5 (e) is a cross-

As shown in FIG. 5, as a prestressed wide-width concrete sleeper according to the prior art, a slim-type concrete sleeper is a PSC sleeper, and in the case of a slim type, a fck is given as 60 MPa.

5 denotes a steel bar, 2 denotes a fixing part reinforcing steel, 3 denotes a tensile reinforcing bar at the bottom of the rail seating surface, 4 denotes a tensile reinforcing bar at the center of the sleeper, 5 denotes a stirrup reinforcing bar, The diameter of the steel bar is 11 mm and the diameter of the reinforcing bar of the fixing part is 10 mm and the diameter of each of the reinforcing bars is 2 at each end, Two 10 mm diameter bars are arranged at the bottom of the rail seating portion, two tensile reinforcing bars at the center of the sleepers are arranged at a diameter of 10 mm, two stirrup bars are arranged at a diameter of 10 mm, As shown in Fig. 5 (b), and the section height of the center portion of the sleeper is given as 125 mm.

However, according to the prior art, steam curing is generally performed at a temperature of about 55 ° C (maximum 60 ° C) for 12 hours to 18 hours when producing PSC sleepers at the production site. Generally, three types of cement (crude steel cement) are used in the production of PSC sleepers. Due to the characteristics of the three kinds of cement, it is reported that there is a problem in the long-term quality of concrete when steam curing is performed. Therefore, in order to improve the durability of concrete sleepers, it is necessary to avoid the use of three kinds of cements and not to apply steam curing as much as possible. However, since the production cost can be reduced due to rapid strength development and demolding, Steam curing is applied to produce prestressed concrete sleepers, as shown in Figs. 4 and 5.

Korean Patent No. 10-1440551 filed on Dec. 28, 2012, entitled " Concrete composition for PC sleepers containing a large amount of blast furnace slag powder " Korean Patent No. 10-954155 filed on October 1, 2009, entitled " Concrete composition for PC sleepers " Korean Patent No. 10-1210595 filed on Sep. 29, 2010, entitled " Heavy Concrete Composition Using Slow-Wound Furnace Slag " Korean Patent No. 10-704991 filed on Dec. 7, 2005, entitled " Wide Sleepers for Packing Tracks " Korean Patent No. 10-660386 filed on Feb. 17, 2004, entitled " High Performance Concrete Composition Using Bottom Ash, Concrete Product and Method for Producing the Product " Korean Patent No. 10-1612113 filed on October 13, 2015, entitled " Binder composition for concrete and concrete composition containing the same " Korean Patent No. 10-1547272 filed on January 22, 2008, entitled " High Strength Cement, Mortar and Concrete Containing Industrial Byproducts " Korean Patent No. 10-1591275 filed on July 30, 2014, entitled " Ultra High Strength Concrete with Improved Workability &

In order to solve the above-mentioned problems, an object of the present invention is to provide an ultra high performance concrete (UHPC), which comprises at least one selected from dolomite, basalt, limestone, granite, (UHPC), and maintain excellent physical properties such as compressive strength, tensile strength and fluidity, and to provide an ultra high performance concrete composition having a 5-mm-grade aggregate.

Another object of the present invention is to provide an ultra high performance concrete having a 5 mm class aggregate which can reduce the sleeper sectional size and the amount of reinforcing material by using ultra high performance concrete (UHPC) composition and improve the abrasion resistance. The present invention relates to an ultra-high performance concrete sleeper for railway.

Another object of the present invention is to provide a super high performance concrete (UHPC) composition, which has a high fluidity and can be demolded after natural curing at a room temperature of less than 24 hours. The present invention provides an ultra-high performance concrete sleeping rail manufactured using high-performance concrete.

As a means for achieving the above technical object, an ultra high performance concrete composition having a 5-mm-grade aggregate according to the present invention comprises 100 parts by weight of cement as a binder; A binder mixed with the cement, wherein 12 to 30 parts by weight of silica fume based on 100 parts by weight of the cement; A binder mixed with the cement, wherein 11 to 30 parts by weight of silica fine powder based on 100 parts by weight of cement; (W / B) of the water-binding material of 0.3 or less as the compounding number to be mixed with the binder, and 19 to 24 parts by weight of water based on 100 parts by weight of the cement; 2 to 5 parts by weight of a superfluidizer mixed with the binder and based on 100 parts by weight of cement; 5 to 26 parts by weight of reinforcing fibers based on 100 parts by weight of cement; Sand mixed with the binder, wherein 70 to 120 parts by weight of fine aggregate based on 100 parts by weight of cement; And 60 to 120 parts by weight of 5-mm-order aggregate aggregate based on 100-parts by weight of cement, wherein the 5-mm-scale aggregate aggregate comprises at least one or more of dolomite, basalt, limestone and granite .

In this case, the 5-mm-grade aggregate is selected to include at least one of dolomite, basalt, limestone and granite having a grain size of 0.1 to 6.0 mm.

The ultra-high performance concrete composition having the 5-mm-grade aggregate according to the present invention is an industrial by-product binder which is mixed with 0 to 40% of the cement so as to replace the cement by volume of 0 to 40 parts by weight Blast furnace slag fine powder may be further included.

The ultra-high performance concrete composition having the 5-mm-class aggregate according to the present invention is an industrial by-product which replaces 0 to 100% of the fine silica powder and has a particle size of 0.2 to 25 탆 m, And 11 to 30 parts by weight of bottom ash.

The fine aggregate is preferably sand having a particle size of 10 탆 to 1.5 탆.

As another means for achieving the above technical object, the ultra high performance concrete sleepers for railways manufactured using the ultra high performance concrete composition having the 5-mm-class aggregate according to the present invention are arranged at predetermined intervals in the longitudinal direction Four steel rods; A fusing unit reinforcing bar disposed at both ends where the rails are disposed, the fusing unit being reinforced by the four bars; A rail seat portion formed at both ends so as to arrange the rails; And a middle portion of the tread formed at the center between the rail seating portions, wherein the rail seating surface portion and the treadmill central portion are formed by placing an ultra high-performance concrete having a 5-mm grade aggregate in a mold; The ultra-high performance concrete having the 5-mm-class aggregate aggregate has 100 parts by weight of cement as a binder; A binder mixed with the cement, wherein 12 to 30 parts by weight of silica fume based on 100 parts by weight of the cement; A binder mixed with the cement, wherein 11 to 30 parts by weight of silica fine powder based on 100 parts by weight of cement; (W / B) of the water-binding material of 0.3 or less as the compounding number to be mixed with the binder, and 19 to 24 parts by weight of water based on 100 parts by weight of the cement; 2 to 5 parts by weight of a superfluidizer mixed with the binder and based on 100 parts by weight of cement; 5 to 26 parts by weight of reinforcing fibers based on 100 parts by weight of cement; Sand mixed with the binder, wherein 70 to 120 parts by weight of fine aggregate based on 100 parts by weight of cement; And 60 to 120 parts by weight of 5-mm-order aggregate aggregate based on 100-parts by weight of cement, wherein the 5-mm-scale aggregate aggregate comprises at least one or more of dolomite, basalt, limestone and granite .

In this case, the diameter of the steel bar is 9.2 mm, the diameter of the reinforcing bars of the fixing part is 10 mm, the height of the cross-section of the rail seating surface is 140 mm, and the height of the cross-

Here, the ultra high performance concrete having the 5-mm-class aggregate aggregate is characterized in that it can be demolded from the mold after natural curing at a temperature of less than 24 hours at a normal outdoor temperature and compaction through high fluidity.

According to the present invention, at least one of dolomite, basalt, limestone, and granite is selected and used as a 5-mm grade aggregate in the production of ultrahigh performance concrete (UHPC) to reduce the manufacturing cost of ultra high performance concrete (UHPC) , Excellent physical properties such as tensile strength and fluidity can be maintained.

According to the present invention, the ultra-high performance concrete (UHPC) composition can be used to reduce the sleeper cross-sectional size and the amount of reinforcing material, for example, PC steel and reinforcing steel, and improve wear resistance.

According to the present invention, the ultra high performance concrete (UHPC) composition can be demolded through high fluidity, and can be demolded after natural curing for 24 hours or less at ordinary outdoor temperature.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a photograph illustrating a PSC sleeper applied on a conventional gravel surface.
FIGS. 2A and 2B are photographs illustrating the occurrence of abrasion on the rail seating surface according to the prior art.
3 is a view schematically showing an ultra high-performance concrete according to the prior art.
4 is a view showing a standard type of concrete sleepers as a prestress wide-width concrete sleepers according to the prior art.
FIG. 5 is a view showing a slim-type concrete sleeper as a prestress wide-width concrete sleeper according to a conventional technique.
FIG. 6 is a schematic view of an ultra high-performance concrete having a 5-mm-grade aggregate according to an embodiment of the present invention.
FIG. 7 is a view illustrating the composition of an ultra-high performance concrete having a 5-mm-grade aggregate according to an embodiment of the present invention.
FIG. 8 is a view showing an ultra-high performance concrete sleeper for railway manufactured using ultra high-performance concrete having 5-mm-grade aggregate according to an embodiment of the present invention.
FIG. 9 is a view showing the construction of a test apparatus based on ASTM C 944 for ultra high-performance concrete having a 5-mm-grade aggregate according to an embodiment of the present invention.
Fig. 10 is a view for explaining the comparison of the wear loss according to the test specimen (specimen) according to the testing apparatus of Fig.
11 is a view for explaining the depth of wear according to the type of the test specimen (specimen) according to the test apparatus of FIG.
12 is a view illustrating a compressive strength test for ultra-high-performance concrete having a 5-mm-grade aggregate according to an embodiment of the present invention.
FIG. 13 is a view illustrating a tensile strength test for an ultra-high-performance concrete having a 5-mm-grade aggregate according to an embodiment of the present invention.
FIGS. 14A to 14C are photographs illustrating ultra-high performance concrete sleepers for railways manufactured using ultra high-performance concrete having 5-mm-class aggregate according to an embodiment of the present invention.

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.

First, coarse aggregate is a natural aggregate and natural stone aggregate. It means aggregate for concrete that is left over 90% (85% in civil engineering) in a 5 mm sieve. For example, in a building, a coarse aggregate Use aggregate. Fine aggregate is fine aggregate such as sand and aggregate that has passed 85% or more by weight in 5 mm sieve. In other words, existing concrete is classified as coarse aggregate above 5mm, and below that as fine aggregate. On the other hand, the most remarkable feature of the ultra high performance concrete composition according to the embodiment of the present invention is that the aggregate having the maximum aggregate size of about 5 mm is selected, and the UHPC composition having various advantages while maintaining excellent physical properties of ultra high performance concrete (UHPC) , And the 5-mm-grade aggregate means an aggregate containing at least one or more of dolomite, basalt, limestone, and granite having a particle size of 0.1 mm to 6 mm.

[Ultra-High Performance Concrete Composition Having 5-mm-Class Screening Aggregate (100)]

FIG. 6 is a schematic view of an ultra-high-performance concrete having a 5-mm-grade aggregate according to an embodiment of the present invention. FIG. 7 is a cross- Fig.

6 and 7, an ultra-high performance concrete 100 having a 5-mm-scale aggregate according to an embodiment of the present invention includes cement 110, silica fume 120, fine silica powder 130, Wherein the blast furnace slag fine powder (140) comprises a slag fine powder (140), water (160), a superabsorbent (170), a reinforcing fiber (180), a fine aggregate (190) The bottom ash 150 may be used as the binder for substituting the cement 110 and the silica fine powder 130. In the ultra-high performance concrete 100 having the 5-mm-class aggregate aggregate according to the embodiment of the present invention, the 5-mm-scale aggregate aggregate 200 includes at least one or more of dolomite, basalt, limestone and granite.

7, in the composition of ultra high performance concrete having the 5-mm-class aggregate according to the embodiment of the present invention, the cement 110 is a binder based on 100 parts by weight of cement, And 55 to 75% by weight, for example, one kind of ordinary Portland cement (OPC).

The silica fume 120 is a binder to be mixed with the cement 110 and may contain 12 to 30 parts by weight based on 100 parts by weight of the cement 110. [ Specifically, when the silica fume 120 is less than 12 parts by weight, the strength development of the ultra high performance concrete is reduced. Accordingly, 12 parts by weight or more is required to exhibit a compressive strength of 150 MPa or more. If the amount of the silica fume (120) exceeds 30 parts by weight, it is difficult to secure the workability as the viscosity increases, and the manufacturing cost may increase.

The silica fine powder 130 is a binder to be mixed with the cement 110 and may contain 11 to 30 parts by weight based on 100 parts by weight of the cement 110. [ Particularly, when the amount of the fine silica powder 130 is less than 11 parts by weight, porosity of the UHPC increases according to a typical Particle Packing Theory calculation, and thus the strength of the UHPC can be reduced. If the amount of the fine silica powder 130 is more than 30 parts by weight, the porosity of the UHPC increases according to a typical Particle Packing Theory calculation. Accordingly, the strength of the UHPC is reduced, Costs can be higher because they are more expensive than silica sand.

The blast furnace slag powder (GGBFS: 140) is an industrial by-product which is mixed with 0 to 40% replacement of the cement 110, and may contain 0 to 40 parts by weight based on 100 parts by weight of the cement 110. Here, the blast furnace slag (140) is a three-kind slag, which is a by-product obtained when producing pig iron in a blast furnace. When the blast furnace slag is partially replaced with cement constituting concrete, it positively affects the environmental and economical aspects Can be expected. In addition, UHPC is a potential hydraulic material that lowers porosity and improves durability, and is a concrete material used throughout the world for many years. Specifically, the blast furnace slag fine powder 140 is a binder for cement substitution and can be substituted by 0 to 40% by volume of the cement. For example, when the blast furnace slag fine powder 140 exceeds 40 parts by weight, the initial strength is lowered due to the initial hydration delay, and an additional activator may be required. The advantage of using the blast furnace slag powder 140 is to increase the fluidity of the concrete and reduce the amount of natural aggregate to be used.

The bottom ash 150 is an industrial by-product which is mixed with 0 to 100% of the silica fine powder 130 to replace the silica fine powder 130. The bottom ash 150 may contain 11 to 30 parts by weight based on 100 parts by weight of the cement 110. Specifically, the bottom ash 150 is a by-product generated in a thermal power plant together with fly ash, and is a coal ash generated in a combustion process of fossil fuel. The bottom ash 150 has a particle size of 0.2 to 25 μm And the silica fine powder 130 may be substituted by 0 to 100%.

The water 160 may be blended with the binder to maintain the ratio W / B of the water-binding material of 0.3 or less, and may contain 19 to 24 parts by weight based on 100 parts by weight of the cement 110 . When the amount of the water 160 is less than 19 parts by weight, the concrete is difficult to form, and the amount of the superabsorbing agent 170 is increased to increase the cost. When the amount of the water 160 is more than 24 parts by weight, .

The superabsorbent 170 may be mixed with the binder and may contain 2 to 5 parts by weight based on 100 parts by weight of the cement (110). Specifically, the colloidal fluidizer 150 is also used as a high performance water reducing agent, and a polycarboxylate system having a solid ratio of 20 to 30% of an admixture is used. For example, when the amount of the superabsorbent 170 is less than 2 parts by weight, mixing of the concrete is difficult, and when the amount is more than 5 parts by weight, the manufacturing cost is increased.

The reinforcing fiber 180 may be a steel fiber mixed with the binder and may contain 5 to 26 parts by weight based on 100 parts by weight of the cement 110. [ Specifically, when the reinforcing fiber 180 is less than 5 parts by weight (or 0.5% of the total volume of the concrete), it is difficult to suppress the brittle fracture of the concrete and the strength is lowered. Further, 26 parts by weight (or 2.5% ), The mixing of the concrete is difficult and the cost is increased.

The fine aggregate (190) is sand mixed with the binder and may contain 70 to 120 parts by weight based on 100 parts by weight of cement (110). Specifically, the fine aggregate 190 uses sand having a particle size of 10 μm to 1.5 mm. For example, when the amount is less than 70 parts by weight, the cost increases. When the weight exceeds 190 parts by weight, the strength may decrease.

The 5-mm-thick coarse aggregate 200 is selected to include at least one of dolomite, basalt, limestone, and granite, and has a particle size of 0.1 to 6.0 mm. 120 parts by weight. For example, if the amount is less than 60 parts by weight, the porosity of UHPC may increase due to the particle packing theory calculation, and the porosity of UHPC may increase due to the particle packing theory calculation even when the amount exceeds 120 parts by weight The strength may be lowered.

Ultimately, in the production of ultra high performance concrete (UHPC) according to the embodiment of the present invention, the cost of manufacturing ultra-high performance concrete (UHPC) by selecting at least one 5 mm class aggregate (dolomite, basalt, limestone, granite, And excellent physical properties such as compressive strength, tensile strength and fluidity can be maintained.

[Ultra-high-performance concrete sleepers for railway manufactured using super high-performance concrete composition with 5-mm-class aggregate aggregate]

8A is a plan view of the ultra-high performance concrete sleeper for railway manufactured using ultra high-performance concrete having 5-mm-grade aggregate according to an embodiment of the present invention, and FIG. 8B is a plan view, 8C is a cross-sectional view of the rail seating surface, and Fig. 8D is a cross-sectional view of the treadmill.

8, an ultra-high performance concrete sleeper for a railroad manufactured using ultra high-performance concrete having a 5-mm-grade aggregate according to an embodiment of the present invention is characterized in that it has a width of 2,400 mm (L) x 360 mm (W) x 140 ㎜ (H) wide width sleeper, which includes ① steel bar, ② fixing part rebar, ③ rail seat part and ④ middle part of the sleepers.

Specifically, the ultra-high performance concrete sleeper for railway manufactured by using the ultra high performance concrete with the 5-mm-class aggregate according to the embodiment of the present invention comprises four steel rods arranged at predetermined intervals in the longitudinal direction (L); A fusing unit reinforcing bar disposed at both ends where the rails are disposed, the fusing unit being reinforced by the four bars; A rail seat portion formed at both ends so as to arrange the rails; And a center portion of the railroad tread formed at the center between the rail seating portions, wherein the rail seating surface portion and the treadmill central portion are formed by placing an ultrahigh performance concrete (UHPC) having a 5 mm grade aggregate in the formwork. In this case, the diameter of the steel bar is 9.2 mm, the diameter of the reinforcing bars of the fixing part is 10 mm, two pieces are arranged at both ends, the cross-sectional height of the rail seating surface is 140 mm, and the cross-

At this time, the ultrahigh performance concrete (UHPC) having the 5-mm grade aggregate has 100 parts by weight of cement 110 as a binder. A binder which is mixed with the cement 110, wherein 12 to 30 parts by weight of the silica fume (120) based on 100 parts by weight of the cement (110); 11 to 30 parts by weight of fine silica powder (130) based on 100 parts by weight of the cement (110) as a binder to be mixed with the cement (110); 19 to 24 parts by weight of water (160) based on 100 parts by weight of the cement (110) are blended so as to maintain the ratio (W / B) of the water- 2 to 5 parts by weight of the superabsorber 170 mixed with the binder and based on 100 parts by weight of the cement 110; Steel fibers mixed into the binder include 5 to 26 parts by weight of reinforcing fibers 180 based on 100 parts by weight of the cement 110; 70 to 120 parts by weight of fine aggregate (190) based on 100 parts by weight of cement (110); And 60 to 120 parts by weight of the 5-mm-grade aggregate (200) based on 100 parts by weight of the cement (110), wherein the 5-mm-scale aggregate (200) comprises dolomite, , Limestone, and granite.

Also, in case of ultra-high performance concrete sleepers for railway manufactured using ultra-high performance concrete with 5-mm grade aggregate according to the embodiment of the present invention, ultra high-performance concrete (UHPC) with 5-mm grade aggregate is used This makes it possible to demolish through high fluidity and mold release after natural curing at less than 24 hours at normal ambient temperature.

As shown in the following Table 1, the ultra-high performance concrete sleeper for railway manufactured by using the ultra high performance concrete having the 5-mm-grade aggregate according to the embodiment of the present invention is the first comparative example (see FIG. 4) The diameter of the steel bar and the height of the cross section can be reduced compared to the second comparative example (see FIG. 5), the diameter of the steel bar is reduced, the tensile reinforcing bar is unnecessary, and the stir bar reinforcing bar can be made unnecessary. In this way, although the section height was decreased, the diameter of the steel bar was reduced, and the reinforcing steel was not applied, the concrete sleeper performance criteria were all satisfied.

Table 1 shows static bending strength test results according to the KRS TR 0008 (Korean Railway Standard, PSC Sleepers) standard. The first and second comparative examples and the 5-mm grade aggregate according to the embodiment of the present invention The results of the test are the mean values of static test results for three specimens for each type.

[Characteristics of Ultra High Performance Concrete with 5mm Class Screening Aggregate]

Table 2 shows the content of the binder in the ultra high-performance concrete having the 5-mm-grade aggregate according to the embodiment of the present invention.

In the case of ultra high-performance concrete having a 5-mm-scale aggregate aggregate according to the embodiment of the present invention, a large amount of industrial by-products are mixed, and the industrial by-products used are blast furnace slag, And bottom ash powder produced in a thermal power plant. Particularly, a blast furnace slag having an average particle diameter of 20 mu m (specific surface area of 3000 cm2 / g) used as a conventional binder for replacing cement can be used.

For example, the replacement of conventional blast furnace slag with 40 vol.% Of cement showed that the fluidity of UHPC was partially increased, while the initial strength at 24 h was significantly reduced. In addition, when the bottom ash fine powder was used in place of the fine silica powder, the fluidity was increased, which was higher than the fluidity when the same amount of fly ash was replaced with the fine silica powder.

In this case, the bottom ash fine powder used was a material having a smaller particle size than that of fly ash, and the result was in contrast to the conventional result that the fluidity of the concrete was inferior when powder having a small particle size was used. For example, UHPC, in which the bottom ash fine powder was replaced with silica fine powder, was found to have an initial compression strength more than twice that of the fly ash having the same volume ratio for 24 hours after pouring. This was contrary to the conventional results, which are generally known to have a low effect on the strength of concrete compared to fly ash. When the bottom ash is broken, it is presumed that this phenomenon will occur because the portion having high pozzolanic reactivity inside the bottom ash is exposed to the outside. By replacing the cement 110 and the fine silica powder 130 with suitable industrial by-products, it is possible to reduce the environmental friendliness and the material cost without greatly reducing the performance.

Meanwhile, when the ultra-high performance concrete (UHPC) according to the embodiment of the present invention is mixed, 5-mm grade aggregate is selected to contain at least one or more of dolomite, basalt, limestone and granite, And it is also possible to maintain mechanical properties such as concrete compression and tensile strength and fluidity.

Table 3 shows the aggregate particle sizes of the first dolomite, the second dolomite and the basalt, which are used as the aggregate of the 5 mm class, in the case of mixing the ultra high performance concrete (UHPC) according to the embodiment of the present invention, , Average particle diameter and specific gravity.

Table 4 shows the weight of the mixture in the ultra high performance concrete composition. Specifically, S represents a silica fine powder as a binder, C represents a bottom ash as a binder, N represents a case in which 5 mm- D represents Dolomite as a 5-mm grade aggregate, B represents Basalt as a 5-mm-grade aggregate, and 1.5 represents the volume fraction of a steel fiber.

For example, SN1.5 indicates that a fine silica powder is used as a binder, a 5-mm-grade aggregate is not used, a steel fiber having a volume fraction of 1.5 is used, SD1.5 is a silica fine powder as a binder, In addition, SB1.5 uses a silica fine powder as a binder, uses basalt as a 5-mm grade aggregate, uses 1.5 volume fraction of a steel fiber as a aggregate of 1.5 volume fraction, Steel fiber is used. In addition, NSC stands for normal-strength concrete and HSC stands for high-strength concrete, respectively.

As shown by the cost index on the right side of Table 5, the ultrahigh performance concrete having the 5-mm-grade aggregate according to the embodiment of the present invention can be reduced by up to 22% compared to the conventional UHPC production cost, , As shown by the compressive strength shown in Table 5, it is possible to obtain a compressive strength of concrete of 140 MPa or more.

In addition, as shown in Table 6, in the case of the ultra high performance concrete having the 5-mm-class screen aggregate according to the embodiment of the present invention, it is possible to obtain a concrete tensile strength of 10 MPa or more, .

[Characteristics of ultra high performance concrete sleeper for railway using ultra high performance concrete with 5mm class screen aggregate]

In the case of ultra-high performance concrete sleepers made of ultra-high performance concrete having a 5-mm grade aggregate according to an embodiment of the present invention, the conventional UHPC It is possible to increase the productivity of 20% or more, and also to reduce the cross-sectional size of the railway sleepers.

Specifically, as described above, the cross-sectional height can be reduced by up to 28%, for example, the cross-sectional height of 195 mm can be reduced to 140 mm, thereby reducing the amount of reinforcing steel, PC steel and reinforcement.

Also, in the case of the ultra-high performance concrete sleeper for railway manufactured using ultra high-performance concrete having the 5-mm-grade aggregate according to the embodiment of the present invention, the diameter of the steel rod, which is the core material of the prestressed concrete sleeper, is reduced to at least 9.2 mm .

Also, in the case of ultra-high performance concrete sleeper for railway manufactured using ultra-high performance concrete with 5-mm grade aggregate according to the embodiment of the present invention, tensile reinforcement steel for crack control due to reduction in section is applied It is possible to secure the structural safety of the railway sleepers by improving the abrasion resistance of the concrete.

In the case of the ultra-high performance concrete sleepers made of ultra-high-performance concrete with 5-mm-grade aggregate according to the embodiment of the present invention, at least 7 times higher than general strength concrete (compressive strength: 40 MPa) (Compression strength: 70 MPa), it is possible to improve abrasion resistance performance at least three times.

Also, in the case of ultra-high performance concrete sleeper for railway manufactured using ultra high-performance concrete with 5-mm grade aggregate according to the embodiment of the present invention, due to high fluidity of ultra high-performance concrete composition, Is unnecessary and can be used to make railway sleepers through natural curing and demolding at normal ambient temperatures within 24 hours, regardless of heat, cold, and normal season. For example, since it is an ultra-high performance concrete composition having a strength of 50 MPa or more per day and a strength of 80 MPa or more per day on the basis of a general outdoor temperature, it is possible to shorten the demolding time and to separate curing The condition becomes unnecessary.

[Test Example]

First, the abrasion resistance performance of ultra high performance concrete (UHPC) using general strength concrete (NSC) (compressive strength: 40 MPa), high strength concrete (HSC) A wear resistance performance test was conducted using the test apparatus shown in FIG. 9 based on ASTM C 944 (Standard Test Method for Abrasion Resistance of Concrete or Mortar Surface by Rotating-Cutter Method).

9 is a view showing the construction of a test apparatus based on ASTM C 944 for an ultra high performance concrete having a 5 mm grade aggregate according to an embodiment of the present invention, Fig. 11 is a view for explaining the comparison of the depth of abrasion according to the type of the test specimen (specimen) according to the test apparatus of Fig. 9. Fig.

As shown in FIG. 10, the UHPC (SD 1.5, CD 1.5, SB 1.5, SN 1.5) of the general strength concrete (NSC-D) showed abrasion resistance seven times higher than that of the general strength concrete (NSC-D). 11, UHPC (SD1.5, CD1.5, SB1.5, SN1.5) was abrasion resistance three times higher than general high strength concrete (HSC-D). Here, SD1.5, CD1.5, SB1.5 and SN1.5 are as shown in Table 4 described above.

Meanwhile, in order to understand the mechanical properties of the ultra-high performance concrete composition having the 5-mm-grade aggregate according to the embodiment of the present invention, the compressive strength and the tensile strength test were carried out. As shown in FIGS. 12 and 13, .

12 is a view illustrating a compressive strength test for an ultra high-performance concrete having a 5-mm-grade aggregate according to an embodiment of the present invention. Fig. 13 (a) shows a tensile strength test and b) shows a cracking property when the tensile strength test is taken as an example. Fig.

14A to 14C are photographs showing ultra-high-performance concrete sleepers for railways manufactured using ultra high-performance concrete having 5-mm-grade aggregate according to an embodiment of the present invention, Fig. 14B illustrates the production of the UHPC sleepers, and Fig. 14C illustrates the results of producing the 14-frame (42 tabs) UHPC sleeper, respectively.

As a result, according to the embodiment of the present invention, it is possible to reduce the amount of the sleeper cross-sectional size and the amount of reinforcement, for example, the amount of PC steel and reinforcing steel using the ultra high performance concrete (UHPC) composition, Also, the high fluidity of the ultra high performance concrete (UHPC) composition enables the demolding of molds after natural curing at 24 hours or less at normal ambient temperature.

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) with 5mm grade aggregate
110: Cement
120: Silica Fume
130: Silica Powder
140: Blast furnace slag powder (GGBFS)
150: Bottom Ash
160: Water
170: Superplasticizer / High performance water reducing agent
180: reinforcing fiber
190: Fine aggregate (sand)
200: 5㎜ grade aggregate (dolomite, basalt, limestone, granite)

Claims (12)

100 parts by weight of cement (110) as a binder;
A binder which is mixed with the cement 110, wherein 12 to 30 parts by weight of the silica fume (120) based on 100 parts by weight of the cement (110);
11 to 30 parts by weight of fine silica powder (130) based on 100 parts by weight of the cement (110) as a binder to be mixed with the cement (110);
19 to 24 parts by weight of water (160) based on 100 parts by weight of the cement (110) are blended so as to maintain the ratio (W / B) of the water-
2 to 5 parts by weight of the superabsorber 170 mixed with the binder and based on 100 parts by weight of the cement 110;
Steel fibers mixed into the binder include 5 to 26 parts by weight of reinforcing fibers 180 based on 100 parts by weight of the cement 110;
70 to 120 parts by weight of fine aggregate (190) based on 100 parts by weight of cement (110); And
60 to 120 parts by weight of 5-mm-grade aggregate (200) based on 100 parts by weight of cement (110)
, ≪ / RTI &
The 5-mm grade aggregate (200) is selected to include at least one of dolomite, basalt, limestone, and granite. The method according to claim 1,
The 5-mm grade aggregate (200) is selected so as to include at least one of dolomite, basalt, limestone and granite having a granular size of 0.1 to 6.0 mm. The ultra-high performance concrete composition . The method according to claim 1,
An industrial byproduct binder which is mixed with 0 to 40% of the cement 110 to replace the cement volume by 0 to 40 parts by weight of a blast furnace slag fine powder (GGBFS: 140) based on 100 parts by weight of the cement 110 Wherein the aggregate is selected from the group consisting of polypropylene and polypropylene. The method according to claim 1,
The industrial byproduct substitutes 0 to 100% of the fine silica powder 130 and has a particle size of 0.2 to 25 탆 m and a bottom ash of 11 to 30 parts by weight based on 100 parts by weight of the cement 110 Lt; RTI ID = 0.0 > 5mm < / RTI > grade aggregate. The method according to claim 1,
Wherein the fine aggregate (190) is sand having a particle size of 10 탆 to 1.5 탆. Four steel bars arranged at predetermined intervals in the longitudinal direction (L); A fusing unit reinforcing bar disposed at both ends where the rails are disposed, the fusing unit being reinforced by the four bars; A rail seat portion formed at both ends so as to arrange the rails; And a center portion of the sleepers formed at the center between the rail seating portions,
Wherein the rail seating surface portion and the treadmill central portion are formed by putting an ultrahigh performance concrete (UHPC) having a 5 mm grade aggregate into a mold; And
The ultrahigh performance concrete (UHPC) having the 5-mm grade aggregate has 100% by weight of cement (110) as a binder; A binder which is mixed with the cement 110, wherein 12 to 30 parts by weight of the silica fume (120) based on 100 parts by weight of the cement (110); 11 to 30 parts by weight of fine silica powder (130) based on 100 parts by weight of the cement (110) as a binder to be mixed with the cement (110); 19 to 24 parts by weight of water (160) based on 100 parts by weight of the cement (110) are blended so as to maintain the ratio (W / B) of the water- 2 to 5 parts by weight of the superabsorber 170 mixed with the binder and based on 100 parts by weight of the cement 110; Steel fibers mixed into the binder include 5 to 26 parts by weight of reinforcing fibers 180 based on 100 parts by weight of the cement 110; 70 to 120 parts by weight of fine aggregate (190) based on 100 parts by weight of cement (110); And 60 to 120 parts by weight of the 5-mm-grade aggregate (200) based on 100 parts by weight of the cement (110), wherein the 5-mm-scale aggregate (200) comprises dolomite, , Limestone, and granite. The ultra-high performance concrete sleeper for railroad manufactured using ultra high-performance concrete with 5-mm-class aggregate aggregate. The method according to claim 6,
The diameter of the steel bar is 9.2 mm, the diameter of the reinforcing bar of the fixing part is 10 mm, the height of the cross-section of the rail seating surface is 140 mm, and the height of the cross- The method according to claim 6,
The ultra-high performance concrete (UHPC) having the 5-mm-class aggregate aggregate can be demolded from the mold after natural curing for 24 hours or less at ordinary outdoor temperature and at high temperature at ordinary outdoor temperature. Ultra high performance concrete sleepers for railway, manufactured using ultra high performance concrete. The method according to claim 6,
The 5-mm-grade screen aggregate 200 is manufactured using ultrahigh-performance concrete having a 5-mm-grade aggregate so that at least one of dolomite, basalt, limestone, and granite having a particle size of 0.1 mm to 6.0 mm is selected. Ultra high performance concrete sleepers for railway. The method according to claim 6,
An industrial byproduct binder which is mixed with 0 to 40% of the cement 110 to replace the cement volume by 0 to 40 parts by weight of a blast furnace slag fine powder (GGBFS: 140) based on 100 parts by weight of the cement 110 High - performance concrete sleepers for railway using ultra - high - performance concrete with 5 - The method according to claim 6,
As industrial by-products replacing 0 to 100% of the fine silica powder 130, 11 to 30 parts by weight of the bottom ashes 150 having a particle size of 0.2 to 25 탆 m and 100 parts by weight of the cement 110 are added High - performance concrete sleepers for railway using ultra - high - performance concrete with 5 - The method according to claim 6,
Wherein the fine aggregate (190) is sand having a particle size of 10 탆 to 1.5 탆. The ultra-high performance concrete sleepers for railroad manufactured using ultra high performance concrete with 5-mm class aggregate aggregate.

Images