CN111216242A - Flat magnetic field orienting device and method for preparing unidirectional orienting steel fiber concrete - Google Patents
Flat magnetic field orienting device and method for preparing unidirectional orienting steel fiber concrete Download PDFInfo
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- CN111216242A CN111216242A CN202010106934.9A CN202010106934A CN111216242A CN 111216242 A CN111216242 A CN 111216242A CN 202010106934 A CN202010106934 A CN 202010106934A CN 111216242 A CN111216242 A CN 111216242A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 316
- 239000010959 steel Substances 0.000 title claims abstract description 316
- 239000000835 fiber Substances 0.000 title claims abstract description 297
- 239000004567 concrete Substances 0.000 title claims abstract description 257
- 238000000034 method Methods 0.000 title claims abstract description 55
- 239000000203 mixture Substances 0.000 claims abstract description 84
- 230000006698 induction Effects 0.000 claims description 21
- 238000010276 construction Methods 0.000 claims description 6
- 229910000828 alnico Inorganic materials 0.000 claims description 5
- 239000000696 magnetic material Substances 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 86
- 239000003638 chemical reducing agent Substances 0.000 description 43
- 239000004568 cement Substances 0.000 description 41
- 239000004576 sand Substances 0.000 description 41
- 239000004575 stone Substances 0.000 description 41
- 229910052755 nonmetal Inorganic materials 0.000 description 32
- 238000003756 stirring Methods 0.000 description 29
- 239000000463 material Substances 0.000 description 19
- 230000000052 comparative effect Effects 0.000 description 15
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 14
- 238000005303 weighing Methods 0.000 description 14
- 239000011210 fiber-reinforced concrete Substances 0.000 description 12
- 238000010998 test method Methods 0.000 description 10
- VQAPWLAUGBBGJI-UHFFFAOYSA-N [B].[Fe].[Rb] Chemical compound [B].[Fe].[Rb] VQAPWLAUGBBGJI-UHFFFAOYSA-N 0.000 description 9
- 238000009826 distribution Methods 0.000 description 8
- 238000012423 maintenance Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 235000021197 fiber intake Nutrition 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 239000002344 surface layer Substances 0.000 description 5
- 230000003014 reinforcing effect Effects 0.000 description 4
- 238000005070 sampling Methods 0.000 description 4
- 238000005452 bending Methods 0.000 description 3
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 description 2
- -1 aluminum nickel cobalt Chemical group 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 229910001172 neodymium magnet Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
- B28C5/40—Mixing specially adapted for preparing mixtures containing fibres
- B28C5/402—Methods
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
- B28C5/40—Mixing specially adapted for preparing mixtures containing fibres
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- Curing Cements, Concrete, And Artificial Stone (AREA)
- Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
Abstract
The invention relates to a flat magnetic field orienting device and a method for preparing unidirectional orienting steel fiber concrete. According to the method for preparing the unidirectional directional steel fiber concrete by using the flat magnetic field directional device, when the steel fiber concrete is prepared and poured to a designated area according to the known method in the field and vibrated, the flat magnetic field directional device is placed on any surface of the steel fiber concrete mixture liquefied by vibration, the magnetic field generated by the device can magnetize the steel fibers which are randomly and randomly oriented in the concrete mixture and drive the steel fibers to rotate to the same direction, and the unidirectional directional steel fiber concrete is prepared after the steel fiber concrete is hardened. The method has the advantage of being used for controlling the direction of the steel fibers in the structural concrete such as terraces, pavements, plates and the like in actual engineering sites.
Description
Technical Field
The invention relates to a method for preparing unidirectional directional steel fiber concrete, in particular to a flat magnetic field directional device for preparing unidirectional directional steel fiber concrete and a method for preparing unidirectional directional steel fiber concrete by the flat magnetic field directional device.
Background
The steel fiber can block the expansion of micro cracks and the formation of macro cracks in the concrete, thereby effectively improving the tensile property of the concrete. Meanwhile, the steel fiber is doped, so that the toughness, the impact resistance and the like of the concrete material are improved, the durability of the concrete material is greatly improved due to the crack resistance of the concrete material to the crack, and the service life of the concrete material is prolonged. Steel fiber reinforced concrete has developed to date and plays an important role in terraces, road surfaces, bridge decks and the like. In the random steel fiber reinforced cement-based composite material, the steel fibers are randomly distributed in the direction, wherein the steel fibers in the tensile stress direction can fully play the role of bridging cracks, thereby improving the tensile property of the material. And the reinforcing effect of the steel fiber different from the tensile stress direction is smaller, so that the reinforcing effect of the steel fiber concrete material along the stress direction is weakened. In the steel fibers randomly distributed in random directions in the floor projects such as pavements, bridge floors and the like, the vertically arranged steel fibers are parallel to the crack surfaces and cannot fully play the role of bridging cracks, so that the crack resistance and the bending strength of the material are not improved, and the reinforcing effect of the steel fibers on the material is reduced. Therefore, the directional distribution of the steel fibers in the floor engineering of the pavement, the bridge deck and the like is realized, the capability of bridging cracks of the steel fibers can be fully exerted, the reinforcing effect of the steel fibers on a matrix is improved, the crack resistance, the bending strength and the like of the steel fibers are further improved, and the economic benefit of the engineering is improved.
The methods for preparing the oriented steel fiber concrete reported in the literature at present comprise an oriented pouring method and an electromagnetic field induction method. According to the invention patent application of a steel fiber directional arrangement device and a steel fiber concrete manufacturing method (application number 201910467797.9, patent publication number CN 110216776A, patent publication date 2019.09.10), steel fibers are fixed and placed in a uniform magnetic field formed by two opposite magnets through adsorption needles to realize the directional arrangement of the steel fibers, and then the steel fibers in the directional arrangement are placed on a concrete surface layer poured layer by layer to form the steel fiber concrete in the directional arrangement of the steel fibers. The invention patent application of a patent of 'method for preparing unidirectional distribution steel fiber reinforced concrete and special equipment thereof' (application number 201010235371.X, patent publication number CN 101913188B, patent publication date 2011.11.30) discloses a method for directionally distributing steel fibers by applying a uniform magnetic field around a non-metal mold filled with steel fiber reinforced concrete. According to the paper (mu jue, Li Hui, Wang Wei, etc.. unidirectionally distributed steel fiber reinforced cement-based composite material (II), preparation and steel fiber reinforcement [ J ], building materials academic newspaper, 2015(03):34-39.), the steel fiber concrete after stirring is placed in a plastic test mold, the test mold is completely placed in a uniform magnetic field in a cavity of an electrified solenoid, the test mold is placed on a vibration table, and the unidirectionally distributed steel fiber concrete with the effective coefficient of the fiber direction reaching 0.90 or above is prepared through the set magnetic field intensity and vibration time. A paper (Ghailan D B, Al-Ghalib AA. magnetic alignment of steel fibers in selected-compacted concrete [ J ]. Australian Journal of Structural Engineering,2019:1-9.) prepares the oriented steel fiber self-compacted concrete with the fiber direction effective coefficient between 0.8 and 0.95 by self-making a cylindrical solenoid coil with the diameter of 200mm and the length of 600mm, placing a 100 x 500mm test mould in the solenoid coil, placing the just-mixed self-compacted concrete in the test mould, combining the low viscosity characteristic of the self-compacted concrete, placing the self-compacted concrete on a vibrating table, and utilizing a uniform magnetic field generated by the coil after power is connected.
Disclosure of Invention
The invention provides a flat magnetic field orienting device and a flat magnetic field orienting method for preparing unidirectional oriented steel fiber concrete.
The technical scheme of the invention is as follows:
the flat magnetic field orienting device for preparing the unidirectional orienting steel fiber concrete is characterized by comprising a flat plate formed by aligning, juxtaposing and combining a plurality of bar magnets in the same polarity.
The surface magnetic induction intensity of the bar magnet is 0.1T-0.5T, and the bar magnet is an aluminum nickel cobalt bar magnet or a neodymium iron boron bar magnet. The magnetic induction is mainly related to the type and size of the magnet.
The device also comprises a shell made of a non-magnetic material, the shell wraps a flat plate combined by a plurality of bar magnets, and a handle is arranged on the surface of the shell, so that the device is convenient to take and place.
The size of the flat plate in the flat magnetic field orienting device is consistent with the size of the action range of the vibrator during vibration of concrete construction, and the larger the action range of the vibrator is, the larger the size of the orienting device is.
The length and width ranges of the flat plate are respectively 200-1000mm and 100-600mm, and when the length of a single bar magnet is insufficient, the bar magnets with small lengths are spliced in the same direction to form the required length.
The invention also provides a method for preparing the unidirectional directional steel fiber concrete by using the flat magnetic field orienting device, which comprises the steps of preparing according to the known method in the field, pouring the steel fiber concrete into a designated area, and vibrating, wherein the flat magnetic field orienting device is placed on any surface of the steel fiber concrete mixture liquefied by vibration, the magnetic field generated by the device can magnetize the steel fibers in the concrete mixture in random directions and drive the steel fibers to rotate to the same direction, and the unidirectional directional steel fiber concrete is prepared after the steel fiber concrete is hardened.
When the slab magnetic field orienting device is adopted to orient the steel fibers in the steel fiber concrete mixture and the vibrating position is gradually moved in the working process of the concrete vibrator, the slab magnetic field orienting device synchronously moves, and the magnetic field always acts on the steel fiber concrete mixture liquefied by vibration.
When the slab magnetic field orienting device is used for orienting steel fibers in the steel fiber concrete mixture, the slab magnetic field orienting device is parallel to the surface of the steel fiber concrete mixture or the surface of a test mold, the distance between the slab magnetic field orienting device and the surface of the steel fiber concrete mixture or the surface of the test mold is 0-200mm, the surface magnetic induction intensity of the bar magnet is 0.1T-0.5T, and the slump of the steel fiber concrete mixture is 50-220 mm.
The plate magnetic field orienting device and the vibrator can synchronously move under manual control, and can also be fixed together with a common surface vibrator to synchronously move the plate magnetic field orienting device and the vibrator, so that the magnetic field always acts on the steel fiber concrete mixture liquefied by vibration.
The invention has the beneficial effects that:
in the prior art, the unidirectional directional steel fiber concrete is oriented by placing the steel fiber concrete in a cavity of an electrified solenoid, but in practical engineering application, the steel fiber concrete is mainly applied to the ground, a terrace and a bridge deck, and the orientation of the steel fiber in the concrete is difficult to realize by the electrified solenoid. Meanwhile, in the prior art, the steel fiber in the concrete is oriented in a mode of pushing out the steel fiber concrete oriented by the energized solenoid by using a piston, but the orientation effect is general and the distribution is uneven. The invention can realize the unidirectional orientation of the steel fiber from the outside of any surface of the steel fiber concrete mixture, and provides possibility for the application of the unidirectional oriented steel fiber concrete in the actual engineering.
The invention provides a method for enabling steel fibers to be oriented more accurately and arranged more uniformly and realizing partial orientation of the steel fibers by adjusting the position of a flat magnetic field orientation device on the outer side of a test piece.
Meanwhile, the device has small volume and convenient movement, can change the orientation depth of the steel fiber by adjusting the height of the orientation device, and is easier to realize in the actual construction work. Compared with the steel fiber concrete prepared by the prior art, the flexural strength of the oriented steel fiber concrete prepared by the method and the special equipment is improved by 20-100%, the bending toughness is improved by 30-200%, the effective coefficient of the steel fiber in the direction is about 0.9 within the range of 0-300mm on the surface layer of the concrete, the specific height range of the surface layer needs to meet the requirement of the effective coefficient of the direction, the distance from the orienting device to the surface layer can be properly adjusted, and the method is completed within the range of the scheme according to the actual engineering requirements.
Drawings
FIG. 1 is a schematic structural diagram of a slab magnetic field orienting device for preparing unidirectional oriented steel fiber concrete by the slab magnetic field orienting device;
FIG. 2a is a schematic view of a larger bar magnet in a slab magnetic field orientation apparatus for producing unidirectional oriented steel fiber concrete by the slab magnetic field orientation apparatus;
FIG. 2b is a schematic view of a smaller bar magnet;
FIG. 2c is a schematic structural view of a plurality of smaller bar magnets spliced to form a large bar magnet;
FIG. 3 is a schematic view of steel fiber concrete unidirectional orientation achieved using a slab magnetic field orientation device using a vibration table;
FIG. 4 is a schematic view of steel fiber concrete unidirectional orientation achieved using a planar magnetic field orienting device using a surface vibrator;
fig. 5 is a schematic diagram of steel fiber concrete unidirectional orientation realized by using a flat magnetic field orientation device under the condition of using a vibrating rod.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
a flat magnetic field orienting device 1 for preparing unidirectional orienting steel fiber concrete is a flat plate formed by aligning and parallelly fixing bar magnets 2 in the same poles; the common length and width ranges of the flat magnetic field orientation device 1 are 200-1000mm and 100-600mm respectively, but the length and width are not limited to the ranges, the specific size is matched with the action range of a vibrator during concrete construction vibration, and the larger the action range of the vibrator is, the larger the size of the flat magnetic field orientation device is. The surface magnetic induction intensity of the bar magnet is 0.1T-0.5T, the bar magnet is an aluminum nickel cobalt bar magnet or a neodymium iron boron bar magnet, and when the length of a single bar magnet is insufficient, the bar magnets with smaller lengths can be spliced in the same direction to form the required length (shown in figure 2 c).
A method for preparing unidirectional directional steel fiber concrete by a flat magnetic field directional device is characterized in that when steel fiber concrete is prepared and poured to a designated area according to a known method in the field and vibrated, the flat magnetic field directional device is placed on any surface of the steel fiber concrete mixture liquefied by vibration, a magnetic field generated by the device can magnetize steel fibers in random directions originally in the concrete mixture and drive the steel fibers to rotate to the same direction, and the unidirectional directional steel fiber concrete is prepared after the steel fiber concrete is hardened. The steel fiber is ensured to rotate to the same direction by controlling the workability of the steel fiber concrete, the magnetic induction intensity of a magnetic field and the action time of the magnetic field (under the vibration condition of a vibrator). In the specific implementation process, the direction of the steel fibers in the concrete can be planed and observed before the concrete is not hardened; the hardened concrete drill core can also be sampled, and the direction of the steel fibers in the hardened concrete drill core can be observed by breaking.
The method for preparing the unidirectional oriented steel fiber concrete by the flat magnetic field orienting device comprises the following steps:
s1, weighing the cementing material, water, sand, stone, a high-efficiency water reducing agent and steel fiber required in actual operation according to the mix proportion of the steel fiber concrete components determined by a design method known in the art, wherein the steel fiber can be low-carbon steel material, putting the weighed cementing material, water, sand, stone and high-efficiency water reducing agent into a stirrer, fully mixing and stirring for 120S, uniformly scattering the steel fiber, adding the weighed mixing water and high-efficiency water reducing agent, and stirring for 60S to prepare a steel fiber concrete mixture;
the known design method of the steel fiber concrete mix proportion can be known from steel fiber concrete structure design and construction rules (CECS 38-1992), steel fiber concrete (JG/T472-2015) and practical handbooks for designing and detecting construction performance of novel and special concrete mix proportion (Wangbei, Chinese architecture publisher, 2004);
the slump of the steel fiber concrete mixture is controlled to be 50-220mm by adjusting a water reducing agent or water consumption;
s2, pouring the prepared steel fiber concrete mixture into a designated area, and vibrating by using a vibrator 4;
the vibrator 4 can be a vibrating table (fig. 3), a surface vibrator (fig. 4) or a vibrating rod (fig. 5) and the like.
S3, placing a flat magnetic field orientation device generating a magnetic field on the external part of any surface of the steel fiber concrete mixture subjected to vibration liquefaction or the surface of a test mould during vibration, and adjusting the direction of the flat magnetic field orientation device according to the required steel fiber orientation direction;
the flat magnetic field orientation device is parallel to the surface of the steel fiber concrete mixture or the surface of the test mold, and the distance between the flat magnetic field orientation device and the surface of the steel fiber concrete mixture or the surface of the test mold is 0-200 mm. The orientation device can be suspended and placed on the support by keeping a certain distance, a cushion block can be added on the surface of the orientation device and the surface of the concrete, the closer the distance between the device and the surface of the concrete is, the larger the orientation range (depth) of the steel fibers in the concrete is, but the higher the possibility that the steel fibers in the concrete are adsorbed to the surface of the magnet is. The depth of the steel fibers to be oriented is determined according to the needs. If the test piece is small in size, the orientation device does not need to move in the implementation process, a certain distance can be kept, and a better orientation effect is achieved. For a large-size structure, the device needs to move in the implementation process, is not convenient to suspend in the air or adopt a bracket or a cushion block, and can be directly placed on the surface without influencing the integral orientation effect of the steel fibers.
When the slab magnetic field orienting device orients the steel fibers in the steel fiber concrete mixture and the concrete vibrator gradually moves the vibrating position in the working process, the slab magnetic field orienting device synchronously moves, and the magnetic field always acts on the steel fiber concrete mixture liquefied by vibration.
And S4, hardening the steel fiber concrete to prepare the unidirectional directional steel fiber concrete.
The flat magnetic field orienting device can realize steel fiber orientation by applying a magnetic field on the surface of a member or a structure (such as a road surface and a terrace), is not limited by size, has higher flexibility and is convenient to use on the site of practical engineering application. The problem that the concrete mixture needs to be placed in an electrified solenoid of the existing orienting device and cannot be applied to actual engineering is solved. The invention aims at concrete structures such as terraces, pavements, plates and the like, adopts a flat plate formed by strip magnets to control the direction of steel fibers, is an uneven magnetic field and mainly realizes the orientation of the steel fibers on the surface layer. The magnetic field can be applied to any outer surface of the member or structure, thereby realizing the application of the actual engineering large-size structure.
Detailed description of the preferred embodiment 1
The flat magnetic field orientation device 1 has the size of 300mm multiplied by 100mm multiplied by 25mm and is formed by aligning and juxtaposing the homopolar of 4 larger bar magnets 21. The bar magnet is an alnico bar magnet with a length of 300mm, a cross section width of 25mm and a height of 25mm, and the surface magnetic induction intensity is 0.1T.
S1, the concrete with the strength grade of C30 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 180: 380: 835: 975: 3.6: and 47, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are cut end hook shapes of low-carbon steel wires, the diameter of the steel fibers is 0.5mm, and the length of the steel fibers is 30 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 160 mm;
s2, pouring the prepared steel fiber concrete mixture into a nonmetal test mold with the thickness of 100mm multiplied by 300 mm;
s3, placing the nonmetal test mold poured with the configured steel fiber concrete mixture on a vibration table, and placing the flat magnetic field orientation device on the top surface of the nonmetal test mold in parallel (as shown in figure 3), wherein the flat magnetic field orientation device is placed on the surface of the steel fiber concrete mixture;
and S4, starting the vibration table, closing the vibration table after vibrating the compact for 40S, and taking away the flat magnetic field orientation device. And then placing the nonmetal test mold on a flat ground, trowelling the test piece, maintaining for 24 hours with the mold, removing the mold, and placing the test piece in a standard maintenance room for maintenance to 28d of age to obtain the directional steel fiber reinforced concrete.
And splitting the directional steel fiber concrete test block from the middle, observing and counting the fiber distribution of the section, wherein the effective coefficient of the steel fiber in the direction is 0.92, and the steel fiber distribution of the section is uniform.
Specific example 2
The flat magnetic field orientation device 1 has the size of 300mm multiplied by 100mm multiplied by 25mm and is formed by aligning and juxtaposing the homopolar of 4 larger bar magnets 21. The bar magnet is an alnico bar magnet with a length of 300mm, a cross section width of 25mm and a height of 25mm, and the surface magnetic induction intensity is 0.1T.
S1, the concrete with the strength grade of C35 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 180: 400: 860: 930: 4: 62, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are low-carbon steel material steel wire cut end hook shapes, the diameter is 0.5mm, and the length is 30 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 100 mm;
s2, pouring the prepared steel fiber concrete mixture into a nonmetal test mold with the thickness of 100mm multiplied by 300 mm;
s3, placing the nonmetal test mold poured with the configured steel fiber concrete mixture on a vibration table, and placing the flat magnetic field orientation device on the top surface of the nonmetal test mold in parallel (as shown in figure 3), wherein the flat magnetic field orientation device is placed on the surface of the steel fiber concrete mixture;
and S4, starting the vibration table, closing the vibration table after vibrating the compact for 40S, and taking away the flat magnetic field orientation device. And then placing the nonmetal test mold on a flat ground, trowelling the test piece, maintaining for 24 hours with the mold, removing the mold, and placing the test piece in a standard maintenance room for maintenance to 28d of age to obtain the directional steel fiber reinforced concrete.
The directional steel fiber concrete test block is split from the middle, fiber distribution of the section is observed and counted, the directional effect of the steel fibers within a range of 35mm from the top surface is good, the effective coefficient of the steel fibers in the direction within the range is 0.93, and the effective coefficient of all the steel fibers in the direction of the section is 0.87.
Specific example 3
The flat magnetic field orientation device 1 has the size of 300mm multiplied by 100mm multiplied by 25mm and is formed by aligning and juxtaposing the homopolar of 4 larger bar magnets 21. The bar magnet is an alnico bar magnet with a length of 300mm, a cross section width of 25mm and a height of 25mm, and the surface magnetic induction intensity is 0.1T.
S1, the concrete with the strength grade of C35 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 180: 400: 900: 900: 4.2: 78, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are low-carbon steel material steel wire cut end hook shapes, the diameter is 0.5mm, and the length is 30 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 80 mm;
s2, pouring the prepared steel fiber concrete mixture into a nonmetal test mold with the thickness of 100mm multiplied by 300 mm;
s3, placing the nonmetal test mold poured with the configured steel fiber concrete mixture on a vibration table, and placing the flat magnetic field orientation device on the top surface of the nonmetal test mold in parallel (as shown in figure 3), wherein the distance between the flat magnetic field orientation device and the surface of the steel fiber concrete mixture is 200 mm;
and S4, starting the vibration table, closing the vibration table after vibrating the compact for 40S, and taking away the flat magnetic field orientation device. And then placing the nonmetal test mold on a flat ground, trowelling the test piece, maintaining for 24 hours with the mold, removing the mold, and placing the test piece in a standard maintenance room for maintenance to 28d of age to obtain the directional steel fiber reinforced concrete.
The directional steel fiber concrete test block is split from the middle, fiber distribution of the section is observed and counted, the directional effect of the steel fibers within a range of 20mm from the top surface is good, the effective coefficient of the steel fibers in the direction within the range is 0.92, and the effective coefficient of all the steel fibers in the direction of the section is 0.65.
Specific example 4
The flat magnetic field orientation device 1 has the size of 200mm multiplied by 150mm multiplied by 25mm and is formed by aligning and juxtaposing the same poles of 6 large bar magnets 22. Big bar magnet 22 adopts 2 to sell long 100mm, the cross-section width is 25mm, highly to form for the 3 concatenations of 25 mm's alnico bar magnet on the market, big bar magnet 22's surface magnetic induction is 0.2T.
S1, the concrete with the strength grade of C40 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 168: 420: 900: 895: 4.5: and 94, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are cut end hook shapes of low-carbon steel wires, the diameter of the steel fibers is 0.5mm, and the length of the steel fibers is 30 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 110 mm;
s2, pouring the prepared steel fiber concrete mixture into a nonmetal test mold with the thickness of 150mm multiplied by 150 mm;
s3, placing the nonmetal test mold poured with the configured steel fiber concrete mixture on a vibration table, and placing the flat magnetic field orientation device on the top surface of the nonmetal test mold in parallel (as shown in figure 3), wherein the flat magnetic field orientation device is placed on the surface of the steel fiber concrete mixture;
and S4, starting the vibration table, closing the vibration table after vibrating the compact for 40S, and taking away the flat magnetic field orientation device. And then placing the nonmetal test mold on a flat ground, trowelling the test piece, maintaining for 24 hours with the mold, removing the mold, and placing the test piece in a standard maintenance room for maintenance to 28d of age to obtain the directional steel fiber reinforced concrete.
The directional steel fiber concrete test block is split from the middle, fiber distribution of the section is observed and counted, the directional effect of the steel fibers on the section is good, and the effective coefficient of the steel fiber direction is 0.94.
Specific example 5
The flat magnetic field orientation device 1 has the size of 400mm multiplied by 100mm multiplied by 25mm and is composed of 4 large bar magnets 22 which are aligned in the same pole and are arranged side by side. The large bar magnet is formed by splicing 2 commercially available rubidium iron boron bar magnets 3 with the length of 200mm, the section width of 25mm and the height of 25mm, and the surface magnetic induction intensity of the large bar magnet 22 is 0.2T.
S1, the concrete with the strength grade of C40 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 168: 420: 865: 935: 4.2: and 47, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are cut end hook shapes of low-carbon steel wires, the diameter of the steel fibers is 0.5mm, and the length of the steel fibers is 30 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 150 mm;
s2, pouring the prepared steel fiber concrete mixture into a nonmetal test mold with the thickness of 100mm multiplied by 400 mm;
s3, placing the nonmetal test mold poured with the configured steel fiber concrete mixture on a vibration table, and placing the flat magnetic field orientation device on the top surface of the nonmetal test mold in parallel (as shown in figure 3), wherein the flat magnetic field orientation device is placed on the surface of the steel fiber concrete mixture;
and S4, starting the vibrator, closing and taking away the vibrator and the flat magnetic field orienting device after vibrating the compact for 40S. And (4) leveling the test piece, curing for 24 hours with the mold, then removing the mold, and placing the test piece in a standard curing room for curing to 28d age to obtain the directional steel fiber reinforced concrete. The flexural strength of the concrete is 8.6MPa according to GBJ 81-1985, a test method for mechanical properties of ordinary concrete.
Comparative example 5
The process was the same as example 5 except that the flat magnetic field orientation device was placed parallel to the top surface of the non-metallic trial mold in the absence of the step S3 in example 5.
And (3) taking the test piece out of the curing chamber when the test piece is cured to the specified 28d age, obtaining the non-oriented steel fiber concrete, and measuring the flexural strength of the non-oriented steel fiber concrete according to GBJ 81-1985, namely the test method for mechanical properties of common concrete, to be 6.2 MPa.
The raw material mixing ratio and the steel fiber consumption of the concrete example 5 and the comparative example 5 are the same, and the 28d flexural strength of the oriented steel fiber concrete obtained by the concrete example 5 is improved by 38.7 percent compared with the 28d flexural strength of the non-oriented steel fiber concrete obtained by the comparative example 5.
Specific example 6
The flat magnetic field orientation device 1 has the size of 400mm multiplied by 100mm multiplied by 25mm and is composed of 4 large bar magnets 22 which are aligned in the same pole and are arranged side by side. The large bar magnet is formed by splicing 2 commercially available rubidium iron boron bar magnets 3 with the length of 200mm, the section width of 25mm and the height of 25mm, and the surface magnetic induction intensity of the large bar magnet 22 is 0.2T.
S1, the concrete with the strength grade of C55 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 165: 450: 865: 935: 5: and 94, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are cut end hook shapes of low-carbon steel wires, the diameter of the steel fibers is 0.5mm, and the length of the steel fibers is 30 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 90 mm;
s2, pouring the prepared steel fiber concrete mixture into a nonmetal test mold with the thickness of 100mm multiplied by 400 mm;
s3, placing the nonmetal test mold poured with the configured steel fiber concrete mixture on a vibration table, and placing the flat magnetic field orientation device on the top surface of the nonmetal test mold in parallel (as shown in figure 3), wherein the flat magnetic field orientation device is placed on the surface of the steel fiber concrete mixture;
and S4, starting the vibrator, closing and taking away the vibrator and the flat magnetic field orienting device after vibrating the compact for 40S. And (4) leveling the test piece, curing for 24 hours with the mold, then removing the mold, and placing the test piece in a standard curing room for curing to 28d age to obtain the directional steel fiber reinforced concrete. The flexural strength of the concrete is 14.8MPa according to GBJ 81-1985, test method for mechanical properties of ordinary concrete.
Comparative example 6
The process was the same as example 6 except that the flat magnetic field orientation device was placed parallel to the top surface of the non-metallic trial mold in the absence of the step S3 in example 6.
And (3) taking the test piece out of the curing chamber when the test piece is cured to the specified 28d age, obtaining the non-oriented steel fiber concrete, and measuring the flexural strength of the non-oriented steel fiber concrete according to GBJ 81-1985, namely a common concrete mechanical property test method, to be 11.8 MPa.
The raw material mixing ratio and the steel fiber consumption of the concrete example 6 and the comparative example 6 are the same, and the 28d flexural strength of the oriented steel fiber concrete obtained by the concrete example 6 is improved by 25.4 percent compared with the 28d flexural strength of the non-oriented steel fiber concrete obtained by the comparative example 6.
Specific example 7
The flat magnetic field orientation device 1 has the size of 400mm multiplied by 100mm multiplied by 25mm and is composed of 4 large bar magnets 22 which are aligned in the same pole and are arranged side by side. The large bar magnet is formed by splicing 4 commercially available rubidium iron boron bar magnets 3 with the length of 100mm, the section width of 25mm and the height of 25mm, and the surface magnetic induction intensity of the large bar magnet 22 is 0.3T.
S1, the concrete with the strength grade of C60 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: 156% steel fiber: 460: 900: 900: 5.8: 117, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are cut end hook shapes of low-carbon steel wires, the diameter of the steel fibers is 0.5mm, and the length of the steel fibers is 30 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 50 mm;
s2, pouring the prepared steel fiber concrete mixture into a nonmetal test mold with the thickness of 100mm multiplied by 400 mm;
s3, placing the nonmetal test mold poured with the configured steel fiber concrete mixture on a vibration table, and placing the flat magnetic field orientation device on the top surface of the nonmetal test mold in parallel (as shown in figure 3), wherein the distance between the flat magnetic field orientation device and the surface of the steel fiber concrete mixture is 100 mm;
and S4, starting the vibrator, closing and taking away the vibrator and the flat magnetic field orienting device after vibrating the compact for 40S. And (4) leveling the test piece, curing for 24 hours with the mold, then removing the mold, and placing the test piece in a standard curing room for curing to 28d age to obtain the directional steel fiber reinforced concrete. The flexural strength of the concrete is 17.9MPa according to GBJ 81-1985, a test method for mechanical properties of ordinary concrete.
Comparative example 7
The process was the same as example 7 except that a flat magnetic field orientation device was placed parallel to the top surface of the non-metallic trial mold, which lacked the step S3 in example 7.
And (3) taking the test piece out of the curing chamber when the test piece is cured to the specified 28d age, obtaining the non-oriented steel fiber concrete, and measuring the flexural strength of the non-oriented steel fiber concrete according to GBJ 81-1985, namely the test method for mechanical properties of common concrete, to be 13.1 MPa.
The raw material mixing ratio and the steel fiber consumption of the concrete example 7 and the comparative example 7 are the same, and the 28d flexural strength of the oriented steel fiber concrete obtained by the concrete example 7 is improved by 36.6 percent compared with the 28d flexural strength of the non-oriented steel fiber concrete obtained by the comparative example 7.
Specific example 8
The flat magnetic field orientation device 1 has the size of 400mm multiplied by 100mm multiplied by 25mm and is composed of 4 large bar magnets 22 which are aligned in the same pole and are arranged side by side. The large bar magnet is formed by splicing 4 commercially available rubidium iron boron bar magnets 3 with the length of 100mm, the section width of 25mm and the height of 25mm, and the surface magnetic induction intensity of the large bar magnet 22 is 0.3T.
S1, the concrete with the strength grade of C45 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 162: 430: 880: 920: 4.5: 70, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are low-carbon steel material steel wire cut end hook shapes, the diameter is 0.5mm, and the length is 30 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 130 mm;
s2, pouring the prepared steel fiber concrete mixture into a nonmetal test mold with the thickness of 100mm multiplied by 400 mm;
s3, placing the nonmetal test mold poured with the configured steel fiber concrete mixture on a vibration table, and placing the flat magnetic field orientation device on the top surface of the nonmetal test mold in parallel (as shown in figure 3), wherein the distance between the flat magnetic field orientation device and the surface of the steel fiber concrete mixture is 200 mm;
and S4, starting the vibrator, closing and taking away the vibrator and the flat magnetic field orienting device after vibrating the compact for 40S. And (4) leveling the test piece, curing for 24 hours with the mold, then removing the mold, and placing the test piece in a standard curing room for curing to 28d age to obtain the directional steel fiber reinforced concrete. The flexural strength of the concrete is 10.7MPa according to GBJ 81-1985, a test method for mechanical properties of ordinary concrete.
Comparative example 8
The process was the same as example 8 except that a flat magnetic field orientation device was placed parallel to the top surface of the non-metallic trial mold, which lacked the step S3 in example 8.
And (3) taking the test piece out of the curing chamber when the test piece is cured to the specified 28d age, obtaining the non-oriented steel fiber concrete, and measuring the flexural strength of the non-oriented steel fiber concrete according to GBJ 81-1985, namely a common concrete mechanical property test method, to be 7.6 MPa.
The raw material mixing ratio and the steel fiber consumption of the concrete example 8 and the comparative example 8 are the same, and the 28d flexural strength of the oriented steel fiber concrete obtained by the concrete example 8 is improved by 40.8 percent compared with the 28d flexural strength of the non-oriented steel fiber concrete obtained by the comparative example 8.
Specific example 9
The flat magnetic field orientation device 1 has the size of 400mm multiplied by 100mm multiplied by 25mm and is composed of 4 large bar magnets 22 which are aligned in the same pole and are arranged side by side. The large bar magnet is formed by splicing 4 commercially available rubidium iron boron bar magnets 3 with the length of 100mm, the section width of 25mm and the height of 25mm, and the surface magnetic induction intensity of the large bar magnet 22 is 0.3T.
S1, the concrete with the strength grade of C45 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 162: 430: 965: 940: 4.4: 62, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are low-carbon steel material steel wire cut end hook shapes, the diameter is 0.5mm, and the length is 30 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 105 mm;
s2, pouring the prepared steel fiber concrete mixture into a nonmetal test mold with the thickness of 100mm multiplied by 400 mm;
s3, placing the nonmetal test mold poured with the configured steel fiber concrete mixture on a vibration table, and placing the flat magnetic field orientation device on the top surface of the nonmetal test mold in parallel (as shown in figure 3), wherein the distance between the flat magnetic field orientation device and the surface of the steel fiber concrete mixture is 100 mm;
and S4, starting the vibrator, closing and taking away the vibrator and the flat magnetic field orienting device after vibrating the compact for 40S. And (4) leveling the test piece, curing for 24 hours with the mold, then removing the mold, and placing the test piece in a standard curing room for curing to 28d age to obtain the directional steel fiber reinforced concrete. The flexural strength of the concrete is 9.7MPa according to GBJ 81-1985, a test method for mechanical properties of ordinary concrete.
Comparative example 9
The process was the same as in example 9 except that S lacked the step S3 in example 9 where a flat magnetic field orientation device was placed parallel to the top surface of the non-metallic trial.
And (3) taking the test piece out of the curing chamber when the test piece is cured to the specified 28d age, obtaining the non-oriented steel fiber concrete, and measuring the flexural strength of the non-oriented steel fiber concrete according to GBJ 81-1985, namely the test method for mechanical properties of common concrete, to be 6.8 MPa.
The raw material mixing ratio and the steel fiber consumption of the concrete example 9 and the comparative example 9 are the same, and the 28d flexural strength of the oriented steel fiber concrete obtained by the concrete example 9 is 42.6 percent higher than the 28d flexural strength of the non-oriented steel fiber concrete obtained by the comparative example 9.
Detailed description of example 10
The flat magnetic field orientation device 1 has the size of 800mm multiplied by 400mm multiplied by 25mm and is formed by aligning 16 large bar magnets 22 with the same poles in parallel. The large bar magnet is formed by splicing 4 commercially available rubidium-iron-boron strong bar magnets 3 with the length of 200mm, the section width of 25mm and the height of 25mm, and the surface magnetic induction intensity of the large bar magnet 22 is 0.3T.
S1, the concrete with the strength grade of C20 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: 185 steel fiber: 320: 835: 1020: 2.1: 25, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are low-carbon steel material steel wire cut end hook shapes, the diameter is 0.75mm, and the length is 60 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 90 mm;
s2, pouring the prepared steel fiber concrete mixture into a terrace with the length of 30m, the width of 12m and the thickness of 180mm, and vibrating while pouring;
s3, vibrating by using a surface vibrator, wherein the effective vibrating range of the vibrator is 0.8m multiplied by 0.4m, and gradually moving and vibrating to compact the whole terrace concrete (as shown in figure 4);
s4, when the vibrating position is gradually moved in the working process of the concrete surface vibrator, the flat magnetic field orienting device synchronously moves, the flat magnetic field orienting device is parallel to the surface of the steel fiber concrete floor, and the flat magnetic field orienting device is directly arranged on the surface of the steel fiber concrete mixture;
and S5, hardening the steel fiber concrete to prepare the unidirectional directional steel fiber concrete terrace.
The results of sampling and detecting the oriented steel fiber concrete terrace show that the steel fiber directions in the terrace concrete within the range of 150mm from the upper surface are horizontally distributed.
Specific example 11
The flat magnetic field orientation device 1 has the size of 800mm multiplied by 400mm multiplied by 25mm and is formed by aligning 16 large bar magnets 22 with the same poles in parallel. The large bar magnet is formed by splicing 8 commercially available rubidium iron boron bar magnets 3 with the length of 100mm, the section width of 25mm and the height of 25mm, and the surface magnetic induction intensity of the large bar magnet 22 is 0.4T.
S1, the concrete with the strength grade of C25 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 175: 350: 830: 1010: 2.7: and 30, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are low-carbon steel material steel wire cut end hook shapes, the diameter is 0.75mm, and the length is 60 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 125 mm;
s2, pouring the prepared steel fiber concrete mixture into a terrace with the length of 30m, the width of 12m and the thickness of 180mm, and vibrating while pouring;
s3, vibrating by using a surface vibrator, wherein the effective vibrating range of the vibrator is 0.8m multiplied by 0.4m, and gradually moving and vibrating to compact the whole terrace concrete (as shown in figure 4);
s4, when the vibrating position is gradually moved in the working process of the concrete surface vibrator, the flat magnetic field device and the vibrator can be fixed together, the flat magnetic field orienting device synchronously moves, the flat magnetic field orienting device is parallel to the surface of the steel fiber concrete floor, and the flat magnetic field orienting device is directly arranged on the surface of the steel fiber concrete mixture;
and S5, hardening the steel fiber concrete to prepare the unidirectional directional steel fiber concrete terrace.
The results of sampling and detecting the oriented steel fiber concrete terrace show that the steel fiber directions in the terrace concrete within 180mm from the upper surface are horizontally distributed.
Detailed description of example 12
The size of the flat magnetic field orientation device 1 is 1000mm multiplied by 600mm multiplied by 25mm, and the flat magnetic field orientation device is formed by aligning and juxtaposing 30 large bar magnets 22 in homopolar mode. The large bar magnet is formed by splicing 5 commercially available rubidium-iron-boron strong bar magnets 3 with the length of 200mm, the section width of 20mm and the height of 25mm, and the surface magnetic induction intensity of the large bar magnet 22 is 0.3T.
S1, the concrete with the strength grade of C30 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 180: 380: 815: 995: 3: 35, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are low-carbon steel material steel wire cut end hook shapes, the diameter is 0.75mm, and the length is 60 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 220 mm;
s2, pouring the prepared steel fiber concrete mixture into a terrace with the length of 30m, the width of 12m and the thickness of 250mm, and vibrating while pouring;
s3, adopting a vibrating rod for vibrating, placing the vibrating rod in the liquefied steel fiber concrete mixture, and gradually moving and vibrating to compact the whole terrace concrete (as shown in figure 5);
s4, when the vibrating position is gradually moved in the working process of the concrete vibrating rod, the flat magnetic field orienting device synchronously moves, the flat magnetic field orienting device is parallel to the surface of the steel fiber concrete terrace, and the flat magnetic field orienting device is directly arranged on the surface of the steel fiber concrete mixture;
and S5, hardening the steel fiber concrete to prepare the unidirectional directional steel fiber concrete terrace.
The results of sampling and detecting the oriented steel fiber concrete terrace show that the steel fiber directions in the terrace concrete within the range of 150mm from the upper surface are horizontally distributed.
Specific example 13
The flat magnetic field orientation device 1 has the size of 1000mm multiplied by 600mm multiplied by 25mm and is formed by aligning and juxtaposing 24 large bar magnets 22 with the same poles. The large bar magnet is formed by splicing 10 commercially available rubidium iron boron bar magnets 3 with the length of 100mm, the section width of 25mm and the height of 25mm, and the surface magnetic induction intensity of the large bar magnet 22 is 0.5T.
S1, the concrete with the strength grade of C35 determined by the known design method comprises the following components in percentage by mass: cement: sand: stone: water reducing agent: steel fiber 180: 400: 810: 985: 3.6: and 40, weighing required amounts of water, cement, sand, stone, a high-efficiency water reducing agent and steel fibers, wherein the steel fibers are low-carbon steel material steel wire cut end hook shapes, the diameter is 0.75mm, and the length is 60 mm. And putting the weighed water, cement, sand and stone into a stirrer, fully mixing and stirring for 120s, uniformly scattering steel fibers, adding the weighed mixing water and the high-efficiency water reducing agent, and continuously stirring for 60 s. The slump of the concrete mixture is 150 mm;
s2, pouring the prepared steel fiber concrete mixture into a terrace with the length of 30m, the width of 12m and the thickness of 250mm, and vibrating while pouring;
s3, adopting a vibrating rod for vibrating, placing the vibrating rod in the liquefied steel fiber concrete mixture, and gradually moving and vibrating to compact the whole terrace concrete (as shown in figure 5);
s4, when the vibrating position is gradually moved in the working process of the concrete vibrating rod, the flat magnetic field orienting device synchronously moves, the flat magnetic field orienting device is parallel to the surface of the steel fiber concrete terrace, and the flat magnetic field orienting device is directly arranged on the surface of the steel fiber concrete mixture;
and S5, hardening the steel fiber concrete to prepare the unidirectional directional steel fiber concrete terrace.
The results of sampling and detecting the oriented steel fiber concrete terrace show that the steel fiber directions in the terrace concrete within the range of 250mm from the upper surface are horizontally distributed.
Nothing in this specification is said to apply to the prior art.
Claims (8)
1. The flat magnetic field orienting device for preparing the unidirectional orienting steel fiber concrete is characterized by comprising a flat plate formed by aligning, juxtaposing and combining a plurality of bar magnets in the same polarity.
2. The orienting device of claim 1 wherein the bar magnet has a surface magnetic induction of 0.1T to 0.5T and is an alnico bar magnet or a ndfeb bar magnet.
3. The orienting device of claim 1 further comprising a housing made of a non-magnetic material, the housing enclosing the plate formed by the plurality of bar magnets, the housing having a handle disposed on a surface thereof.
4. The orienting device of claim 1 wherein the plate in the plate magnetic field orienting device has a size consistent with the range of action of the vibrator during vibration of concrete construction.
5. The orienting device of claim 1 wherein the length and width of the plates are in the range of 200-1000mm, 100-600mm, respectively, and when the length of a single bar magnet is insufficient, the bar magnets of small length are spliced in the same direction to a desired length.
6. A method for preparing unidirectionally oriented steel fiber concrete by using the flat magnetic field orienting device as claimed in any one of claims 1 to 5, wherein the steel fiber concrete is prepared and poured into a designated area according to a method known in the art, and then vibrated, the flat magnetic field orienting device is placed on any one surface of the steel fiber concrete mixture subjected to vibration liquefaction, the magnetic field generated by the device can magnetize the essentially randomly disoriented steel fibers in the concrete mixture and drive the steel fibers to rotate to the same direction, and the unidirectionally oriented steel fiber concrete is prepared after the steel fiber concrete is hardened.
7. The method for preparing unidirectionally oriented steel fiber concrete according to claim 6, wherein when the slab magnetic field orienting device is used to orient the steel fibers in the steel fiber concrete mixture, the slab magnetic field orienting device is moved synchronously while the vibrating position is moved gradually during the operation of the concrete vibrator, and the magnetic field always acts on the vibrated and liquefied steel fiber concrete mixture.
8. The method for preparing unidirectionally oriented steel fiber concrete according to claim 6, wherein the steel fibers in the steel fiber concrete mixture are oriented by the plate magnetic field orientation device, the plate magnetic field orientation device is parallel to the surface of the steel fiber concrete mixture or the surface of the test mold, the distance between the plate magnetic field orientation device and the surface of the steel fiber concrete mixture or the surface of the test mold is 0-200mm, the surface magnetic induction intensity of the bar magnet is 0.1T-0.5T, and the slump of the steel fiber concrete mixture is 50-220 mm.
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| CN112942764A (en) * | 2021-01-29 | 2021-06-11 | 武汉固立达建筑科技有限公司 | Terrace integrated structure and construction method thereof |
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| CN114714496A (en) * | 2022-04-29 | 2022-07-08 | 重庆交通大学 | Steel fiber directional reinforced self-compacting concrete forming device and using method |
| CN116082002A (en) * | 2023-02-23 | 2023-05-09 | 河北工业大学 | High-performance graded directional fiber concrete member and preparation method and application thereof |
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