CN115216966A - Fiber bundle, preparation method and application thereof, and fiber-reinforced composite material - Google Patents
Fiber bundle, preparation method and application thereof, and fiber-reinforced composite material Download PDFInfo
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- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
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- D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
- D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
- D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D06M15/263—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acids; Salts or esters thereof
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- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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Abstract
The invention belongs to the technical field of reinforced materials, and particularly relates to a fiber bundle, a preparation method and application thereof, and a fiber reinforced composite material. The present invention combines a plurality of monofilament fibers together to form a fiber bundle, each fiber filament having a surface aid on the surface thereof to increase frictional polymerization between the fibers, and then applies a binder coating on the outer surface of the fiber bundle. The fiber bundles are provided with single fiber filaments, and the fiber filaments are mainly limited by surrounding fiber filaments through friction rather than bonding, so that gradual but independent fiber breakage or extraction is allowed, the occurrence of failure of the whole fiber bundles caused by the single fiber filament breakage or extraction is delayed, the effect of fiber bridging is realized, the premature fiber extraction is avoided, the high bonding strength between the fiber bundles and a composite base material can be fully utilized, the high composite strength is realized, the fiber bundle breakage can be delayed, and the tensile property (strength, ductility and toughness) of the fiber bundle reinforced composite material is improved.
Description
Technical Field
The invention belongs to the technical field of reinforced materials, and particularly relates to a fiber bundle, a preparation method and application thereof, and a fiber reinforced composite material.
Background
Because the components of the concrete are widely available and cheap, the cement and the concrete are the building materials which are used most frequently in the world. However, the low toughness and susceptibility to defects of concrete result in poor tensile properties, low tensile strength and low ductility. While low ductility is the primary cause of catastrophic failure of concrete, which is typical of brittle materials. Thus, concrete is traditionally considered a material that can only withstand compression, while rebar is incorporated into the structural design as a tension member for withstanding tension. However, cracking and spalling of the concrete often results in exposure of the steel reinforcement, making corrosive substances such as chloride ions more likely to migrate and attack the steel reinforcement, further causing cracking and spalling of the concrete and ultimately affecting the integrity of the building structure.
In order to improve the problem of poor tensile properties of concrete, it is common to add short fibers to the concrete mixture to increase the ultimate tensile strength of the concrete, i.e., fiber reinforced concrete. However, most of the commercial short fibers currently used for concrete are in the form of monofilaments, and although a few of them exist in the form of fiber bundles, the fiber bundles are completely impregnated with resin to be integrated as large-diameter monofilament fibers, or the fiber bundles are separated into monofilaments during mixing with concrete. Thus, such discrete fibers (including monofilaments and the fiber bundles described above) tend to break under load, particularly when their interfacial bond strength with the concrete substrate is high. And an immediate load drop occurs at the onset of fiber breakage, resulting in brittle failure of the concrete, as in ordinary concrete breakage. Therefore, there is a need to develop a fiber material that avoids early fiber breakage or fiber pull-out, thereby avoiding the impact on the tensile properties of fiber reinforced concrete.
Disclosure of Invention
In view of the above, the present invention provides a fiber bundle, a preparation method and an application thereof, and a fiber reinforced composite material, wherein the fiber bundle provided by the present invention can avoid early fiber fracture or early fiber extraction, and improve the tensile property of the fiber reinforced composite material.
In order to achieve the purpose, the invention provides the following technical scheme:
the invention provides a fiber bundle, which comprises a modified fiber bundle and a binder coating coated on the surface of the modified fiber bundle, wherein the modified fiber bundle is obtained by gathering modified fiber yarns, and each modified fiber yarn comprises a fiber yarn matrix and a surface auxiliary agent attached to the surface of the fiber yarn matrix.
Preferably, the diameter of the fiber bundle is 0.1-5 mm; the length of the fiber bundle is 5-60 mm; the ratio of the length to the diameter of the fiber bundle is (10-250): 1.
Preferably, the binder comprises one or more of acrylic acid, phenolic resin, epoxy resin, latex, polyester, cellulose ether, vinyl ester, vinyl acetate, polyacrylamide, phosphate, polyurethane and urea; the mass ratio of the binder to the fiber bundle is (1-100): 1000.
Preferably, the fiber yarn is made of one or more of aramid fiber, polyvinyl alcohol, polyester, glass, carbon, basalt, polypropylene, polyethylene, polyformaldehyde, polyamide, acrylic acid, natural fiber, ceramic and steel.
Preferably, the number of the fiber filaments in each fiber bundle is 50-3000; the diameter of the single fiber filament is 5-200 mu m.
Preferably, the surface auxiliary agent comprises one or more of oil, polyethylene glycol, silicate, dimethyl urea derivative, lithium chloride and butyl stearate; the mass ratio of the surface auxiliary agent to the fiber yarn is (5-65) 1000.
The invention also provides a preparation method of the fiber bundle in the technical scheme, which comprises the following steps:
collecting a plurality of fiber filaments coated with the surface auxiliary agent on the surface to form fasciculate fibers;
and coating the outer surface of the fasciculate fiber with a bonding agent to obtain the fiber bundle.
The invention also provides the application of the fiber bundle in the technical scheme or the fiber bundle prepared by the preparation method in the technical scheme in a fiber reinforced material.
The invention also provides a fiber reinforced composite material, which comprises fiber bundles and a base material; the fiber bundles are dispersed in the base material; the fiber bundle is the fiber bundle of the technical scheme or the fiber bundle prepared by the preparation method of the technical scheme.
Preferably, the substrate comprises one or more of cement, cement-based binder, polymer, ceramic and metal.
The invention provides a fiber bundle, which comprises a modified fiber bundle and a binder coating coated on the surface of the modified fiber bundle, wherein the modified fiber bundle is obtained by gathering modified fiber yarns, and each modified fiber yarn comprises a fiber yarn matrix and a surface auxiliary agent attached to the surface of the fiber yarn matrix. The present invention combines a plurality of monofilament fibers together to form a fiber bundle, each fiber filament having a surface aid on the surface thereof to increase frictional polymerization between the fibers, and then applies a binder coating on the outer surface of the fiber bundle. The fiber bundles are provided with single fiber filaments, the fiber filaments are mainly limited by surrounding fiber filaments through friction rather than bonding, so that the gradual and independent fiber breakage or extraction is allowed, the occurrence of the failure of the whole fiber bundle caused by the single fiber filament breakage or extraction is delayed, the effect of fiber bridging is realized, the premature fiber extraction is avoided, the high bonding strength between the fiber bundles and a composite base material can be fully utilized, the high composite strength is realized, the fiber bundle breakage is delayed, and the tensile property (strength, ductility and toughness) of the fiber bundle reinforced composite material is improved.
In addition, the fiber bundle provided by the present invention enhances good dispersibility of the fiber bundle during and after mixing with the base material, and maintains excellent fluidity of the base material itself.
Drawings
FIG. 1 is a cross-sectional view of a fiber bundle of example 1 of the present invention, wherein 10 is a fiber bundle and 12 is a fiber filament; 14 is a surface auxiliary agent, 16 is a binder coating;
FIG. 2 is a tensile stress-strain plot of a conventional FRC and a HPFRC of application example 1 of the present invention;
FIG. 3 is a graph of Vebe time versus fiber usage for various fiber bundle length to bundle diameter ratios.
Detailed Description
The invention provides a fiber bundle, which comprises a modified fiber bundle and a binder coating coated on the surface of the modified fiber bundle, wherein the modified fiber bundle is obtained by gathering modified fiber yarns, and each modified fiber yarn comprises a fiber yarn matrix and a surface auxiliary agent attached to the surface of the fiber yarn matrix.
Unless otherwise specified, the present invention is not limited to the source of the raw materials used, and commercially available products known to those skilled in the art may be used.
In the present invention, the diameter of the fiber bundle is preferably 0.1 to 5mm, more preferably 0.4 to 3mm, and most preferably 0.5 to 1mm; the length of the fiber bundle is preferably 5 to 60mm, more preferably 10 to 50mm, and most preferably 12 to 40mm; the ratio of the length to the diameter of the fiber bundle is preferably (10 to 250): 1, more preferably (40 to 150): 1, and most preferably (50 to 100): 1.
A schematic representation of the fiber bundle prepared in example 1 of the present invention is shown in FIG. 1, wherein 10 is the fiber bundle and 12 is the fiber filament; 14 is a surface auxiliary agent and 16 is an adhesive coating. The diameter of the fiber bundle in the present invention depends on the diameter and number of filaments in each bundle.
In the present invention, the binder preferably comprises one or more of acrylic acid, phenolic resin, epoxy resin, latex, polyester, cellulose ether, vinyl ester, vinyl acetate, polyacrylamide, phosphate, polyurethane and urea, and more preferably is phenolic resin, epoxy resin or polyurethane; when the adhesive is various, the proportion of different adhesives is not specially limited, and the adhesive can be prepared at any proportion; the mass ratio of the binder to the fiber bundle is preferably (1 to 100): 1000, and more preferably (5 to 50): 1000.
In the present invention, the binder preferably comprises an emulsion, a coupling agent, an acid and a nanoparticle suspension, more preferably an emulsion and a coupling agent; the nano particles in the nano particle suspension preferably comprise one or more of Carbon Nano Tubes (CNT), carbon Nano Fibers (CNF), graphene oxide, nano silicon dioxide and nano calcium carbonate, and more preferably comprise Carbon Nano Tubes (CNT), carbon Nano Fibers (CNF), graphene oxide or nano silicon dioxide; when the nano particles are the above, the proportion of different types of nano particles is not particularly limited, and the nano particles can be prepared at any proportion.
In the present invention, the binder also preferably contains an active polar functional group that forms a covalent bond or a hydrogen bond with the substrate; the active polar functional group preferably comprises one or more of carboxyl, hydroxyl and epoxy; when the active polar functional groups are the above-mentioned groups, the proportion of different active polar functional groups is not particularly limited, and the active polar functional groups can be prepared at any proportion.
In the invention, the fiber filaments are preferably made of one or more of aramid, polyvinyl alcohol, polyester, glass, carbon, basalt, polypropylene, polyethylene, polyformaldehyde, polyamide, acrylic acid, natural fibers, ceramics and steel, and more preferably made of aramid, glass, polyethylene or basalt; when the fiber yarn is made of various materials, the invention has no special limitation on the mixture ratio of the fiber yarns made of different materials, and the mixture ratio can be any.
In the present invention, the number of the fiber filaments in each fiber bundle is preferably 50 to 3000, more preferably 500 to 2000, and most preferably 700 to 1600; the individual filaments preferably have a diameter of from 5 to 200. Mu.m, more preferably from 10 to 100. Mu.m, most preferably from 10 to 50 μm.
In the present invention, the filaments are preferably twisted filaments; the twist angle of each twisted fiber is preferably 0 to 100 turns, and more preferably 1 to 40 turns.
In the present invention, the surface auxiliary agent preferably includes one or more of oil, polyethylene glycol, silicate, dimethyl urea derivative, lithium chloride and butyl stearate, and more preferably is natural oil; the natural oil preferably includes carboxyl, ester and hydroxyl functional groups; when the surface additives are various, the invention has no special limitation on the mixture ratio of different surface additives, and the surface additives can be mixed at any ratio; the mass ratio of the surface auxiliary agent to the fiber yarn is preferably (5-65): 1000, and more preferably (10-40): 1000.
The invention also provides a preparation method of the fiber bundle in the technical scheme, which comprises the following steps:
collecting a plurality of fiber filaments coated with the surface auxiliary agent on the surface to form fasciculate fibers;
and coating the outer surface of the fasciculate fiber with a bonding agent to obtain the fiber bundle.
The process of assembling and coating is not particularly limited in the present invention, and the assembling and coating process well known in the art may be used.
The present invention preferably further comprises: and carrying out oxidation modification on the surfaces of the fasciculate fibers to obtain the fiber bundles.
In the present invention, the oxidation modification is preferably performed by plasma oxidation or ozone oxidation.
In the present invention, the fiber bundle is preferably chopped from a continuous fiber yarn; the chopping apparatus is preferably a conventional cutting head, more preferably a hot cutting head.
In the present invention, it is preferable that the bundle-like fibers whose surfaces are coated with an adhesive or whose surfaces are oxidized and modified are thermally cut to fuse the cut ends. In the present invention, the apparatus for thermal cutting is preferably a heated cutting head, a heated knife, a plasma cutter, or a laser cutter. The art can select a thermal cutting tool according to actual conditions.
The present invention produces a melt-set cut end by thermally cutting the fiber bundle, which may be advantageous for maintaining the bundle shape during mixing with the substrate and may provide better bond resistance during fiber bundle pull-out when loading the composite.
The invention also provides the application of the fiber bundle in the technical scheme or the fiber bundle prepared by the preparation method in the technical scheme in a fiber reinforced material.
The invention also provides a fiber reinforced composite material, which comprises fiber bundles and a base material; the fiber bundles are dispersed in the base material; the fiber bundle is the fiber bundle of the technical scheme or the fiber bundle prepared by the preparation method of the technical scheme.
In the present invention, the substrate preferably comprises one or more of cement, cement-based binder, polymer, ceramic and metal, more preferably cement or cement-based binder; when the base materials are various, the mixture ratio of different base materials is not specially limited, and any mixture ratio can be adopted; the cement is preferably one or more of portland cement, high-alumina cement, sulphoaluminate cement, alkali-activated cement, magnesium cement, slag cement, geopolymer cement and gypsum cement, and is more preferably portland cement; when the cement is various, the proportion of different types of cement is not specially limited, and the cement can be prepared in any proportion.
The preparation method of the fiber reinforced composite material is not particularly limited, and a proper preparation method can be selected according to actual needs in the field. If the strength requirements of the desired fiber-reinforced composite are high, all fiber bundles can be distributed uniformly in spatial position and direction and the bundle-like form of the fiber bundles is maintained during the preparation process. In addition, the fiber bundles can also be opened and dispersed during the preparation process to provide a more uniform distribution of the individual filaments. In order to prevent premature breakage of the fiber bundle or fiber extraction, it is most important to control the cohesiveness and flexibility of the fiber bundle by adjusting the fiber filament size, the number of fiber filaments per bundle, the fiber bundle size, the fiber twist angle, the type and content of the surface aids of the fiber filaments, and the type and content of the binder.
A schematic diagram of the fiber bundle of example 1 of the present invention is shown in fig. 1, wherein the diameter of the fiber bundle depends on the diameter and number of fibers per fiber strand.
The law of fiber bridging describes the relationship between the mean stress (σ) carried by a fiber bridged by a crack in a substrate and the opening (δ) of the crack. For randomly oriented staple fibers and fiber pull-outs (rather than fiber breaks, when a fiber break occurs, the following equations (1) and (2) should be modified accordingly, the bridge law can be derived as:
wherein the content of the first and second substances,
is the crack opening, corresponding to the maximum bridging stress:
wherein g = friction factor; τ = bond strength; d f = fiber diameter; l is f = fiber length; η = V f E f /V m E m (ii) a E = modulus; v = volume fraction; and subscripts f and m refer to the fiber and the substrate, respectively.
The additional bridging force due to the presence of aggregate in the concrete can be expressed as:
wherein σ mu Is the stress, delta, of ordinary concrete at the time of initial cracking c And p is an empirical parameter.
Thus, the total bridging stress is the sum of equations (1) and (3). Equations (1) - (3) represent all relevant micro-parameters that can be used to guide the selection of the desired material composition, including fiber type and fiber size (fiber length and diameter), to control crack opening. Furthermore, the conditions for pseudo strain hardening depend on the critical fiber volume fraction V f crit Defined as the minimum amount of fiber required for multiple splitting. This results in
Wherein J tip Is the toughness of the substrate.
Equation (4) clearly shows that when the substrate toughness is low (J) tip ) Strong interfacial adhesion (τ) and high fiber aspect ratio (L) f /d f ) Are advantageous for the generation of pseudo strain hardening. However, high strength substrates that result in high strength composites generally have high toughness. Thus, the pseudo strain hardening behavior of such composites is likely to be inhibited unless the fiber volume fraction, fiber aspect ratio, and bond strength can be greatly increased. Well known, high (L) f /d f ) And high V f All due to the increased stirring and pouring difficulty and high production costThe odor is very famous. Therefore, it is most effective when the high adhesive strength can be fully utilized. Furthermore, a high bond strength also contributes to the maximum bridging stress of the reinforced composite (ultimate strength, see equation (2)).
Effective bond strength can be defined as:
τ eff ＝τA exposed /A total (5)
τ eff = effective bond strength
τ = actual bond strength per fiber (as obtained from the pull-out test)
A exposed = exposed surface area of fiber bundle along its circumference
A total = total surface area per fiber strand = N (pi d) f )
N = number of filaments per tow
d f = individual filament diameter
(1) Hydrophilic fiber
Due to A exposed ＝Rπ 2
D f =2R = fiber bundle diameter,
r = radius of the fiber bundle, and
R＝SQRT(N/V fb )d f /2, assume V fb = fiber solids fraction per bundle (not related to V) f Confusion), then
A exposed /A total ＝Rπ 2 /(πd f N)＝π/2 SQRT(1/(NV fb )) (6)
Namely that
Since the tau of aramid and PVA fibers is too strong (fibers are always broken), a relatively large number of fibers (i.e., N) must be used to reduce tau eff . In addition, in order to prevent fiber breakage, it is necessary to ensure the fiber bundle length (L) f ) Less than the critical fiber length L f crit 。
And
L f <L f crit (9)
wherein σ fu Is the fiber breaking strength.
In the following examples, τ =4.5MPa is used. This value represents the typical high bond strength of hydrophilic fibers with cement.
(2) Hydrophobic fibers
τ eff ＝τ bundle >τ (10)
Where τ = actual bond strength of the fiber (e.g. obtained from a pull-out test)
τ bundle = enhanced bond strength of the outer surface of the fiber bundle due to additional binder coating
Since hydrophobic fibers generally have a low τ, resulting in easy fiber pull-out, it is preferred to use an additional binder to increase the bond strength (τ) bundle ) Thereby achieving the purpose of improving the composite strength. Further, in order to prevent fiber breakage, it is preferable to ensure the fiber bundle length (L) f ) Less than the critical beam length L f crit 。
And
L f <L f crit (12)
wherein sigma fu Is the fiber breaking strength.
Considerations for the ratio of bundle length to bundle diameter:
as mentioned above, in order to achieve the goal of optimizing the mechanical properties (including strength, ductility and toughness) of a fiber-reinforced composite, it is necessary to simultaneously optimize a plurality of parameters of the fiber bundle. It is common practice in the construction industry to consider how to further increase the strength of various fibers on the fiber filaments to avoid fiber breakage in concrete composites. Fiber filament strength depends on the presence of micro-defects that must be eliminated by producing smaller diameter fiber filaments, and most research and development efforts are directed toward making smaller micron-sized fibers. This manufacturing process is generally costly and therefore the fiber cost is much higher. More troublesome is that although longer fibers can be used to increase the strength of the composite due to their higher strength, longer fibers can significantly reduce the flowability of the composite in addition to creating dispersion problems in the composite. The fiber bundles described in the present invention can follow the general bridging law of fiber-filament composites, which is based primarily on the innovative concept of effective bond strength as set forth in the present invention. Thus, the present invention can be easily designed and implemented such that the ratio of the fiber bundle length to the bundle diameter also satisfies the optimum flowability range. The Vebe time is directly related to the flowability of the composite; a short Vebe time indicates good flow.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.
Example 1
Gathering 700 fiber filaments (made of aramid fibers and having a diameter of 12 microns) coated with a natural oil surface additive (and the mass ratio of the fiber filaments is 2.5);
size of fiber bundle: n =700,l f ＝50mm；
V fb =0.907 (tightly packed fiber bundle);
A exposed /A total =0.06 (equation (6))
I.e. tau eff = 0.06X 4.5MPa =0.27MPa (equation (5))
And σ fu =2250 MPa, d f ＝12μm，
L f crit =2250 mpa × 12 μm/(2 × 0.27 mpa) =50.0 mm(equation (8))
So L f ＝50mm<L f crit ->OK. (Eq. 9)
Expected composite tensile strength under direct tension:
suppose V f ＝2％，g＝2
Example 2
Collecting 700 fiber yarns (which are made of aramid fibers and have the diameter of 12 microns) coated with a natural oil surface auxiliary agent (and the mass ratio of the fiber yarns is 2.5) to form a bundle fiber, and then coating a polyurethane binder (and the mass ratio of the fiber bundles is 3;
application example 1
The cement composite material is made of conventional aramid fiber monofilaments and the aramid fiber bundles of the present invention separately. In both cases the same aramid fiber material was used. For conventional Fiber Reinforced Concrete (FRC), two commercially available aramid fiber monofilaments with fiber lengths of 6mm and 12mm were used. For High Performance Fiber Reinforced Concrete (HPFRC), the high efficiency fiber bundle (L) shown in example 1 was used f =50mm, n = 700). The substrate compositions were all the same and all had a fixed fiber content of 2 volume percent.
Performance testing
(1) A direct tensile test was performed on the fiber bundle reinforced cement composite of example 1 to evaluate its respective mechanical properties. The method comprises the following specific steps: adding the cement formula and water into a stirrer, stirring for 10min, gradually adding the fibers, continuously stirring for 5min, pouring into a plate-shaped mould (76 × 12 × 305 mm) after uniformly stirring, demoulding after one day, curing the fiber reinforced cement plate-shaped test piece for 28d at room temperature, and then performing direct tensile test. The results are shown in FIG. 2.
As can be seen from fig. 2, for a conventional FRC reinforced with 12mm long filaments, catastrophic failure occurred after reaching a peak load of 4 MPa. The strength is only slightly increased over the tensile strength of ordinary concrete (about 2-3 MPa). And 0.05% ductility (strain at peak load) is about the same as that of ordinary concrete. Toughness (0.32 kJ/m) 2 ) The most important gain is obtained by a descending curve which is beneficial to overlong, and the toughness of the common concrete is only 0.01 to 0.1kJ/m 2 . For a conventional FRC of 6mm length, some degree of multiple cracking was observed resulting in ductility (0.4%) and toughness (8.4 kJ/m) 2 ) Is remarkably improved; the composite strength increased to 5mpa. The strength of the composite material is up to 13MPa, the ductility is up to 2.2 percent, and the toughness is up to 28.7kJ/m 2 . These values represent 4-6, 44 and 2-3 orders of magnitude increases in strength, ductility and toughness, respectively, over ordinary concrete.
(2) The Vebe time of the fiber bundle reinforced composite material for the fiber bundles of different lengths of example 2 is plotted against the amount of fiber used in FIG. 3.
As can be seen from FIG. 3, the fiber bundles of 12mm, 20mm and 50mm in length correspond to 10%, 5% and 0.5% of critical fiber contents. When high strength concrete is selected, a fiber content of 2% by volume (or 1.3% by weight) is considered suitable in terms of cost, strength and ductility of such concrete composite. L is a radical of an alcohol f /D f Vebe times of 60 and 100 are very low (about 3 seconds, and therefore have excellent flowability), while L f /D f =250 shows a Vebe time of about 15 seconds and the flowability is significantly impaired. The large fluidity differences predicted above were also verified in the 12 and 20mm tow and 50mm tow to concrete mix tests. The Vebe time increases abruptly when the fiber content in the composite material exceeds a critical value, which depends largely on the ratio of the fiber bundle length to the bundle diameter. The ratio provided by the present invention is falling within the ideal range corresponding to low Vebe times, thereby ensuring fiber bundle reinforced compoundingExcellent flowability of the material.
It should be noted that commercially available filaments of ultra-high molecular weight polyethylene or polyvinyl alcohol have a diameter of 20-40 μm. When using fiber lengths of 8mm or 12mm, the corresponding L f /d f The range is between 300-600. Many cement composites have been widely reported to exhibit very poor flow and non-uniform fiber dispersion when reinforced with 2% fiber volume.
(3) Compression and bending test
The fiber bundle (L) of example 1 was treated f =50mm, n = 700), also for reinforced ultra high performance concrete, and subjected to compression and bending tests. The test results are listed in table 1.
Table 1 table of properties of the fiber bundle of example 1
In the case of HC-UHPC-1, very low fiber content is used to maximize cost efficiency while achieving very high compressive strength and high flexural strength. For HC-UHPC-2, a medium fiber content was used to further increase the flexural strength. For HC-UHPC, the fibre content used is significantly lower than for typical ultra-high performance fibre-reinforced concrete (usually V with f Steel fibres of = 2%) while providing similar or even superior strength properties. This low fiber dosage is a viable solution due to the unique design of high efficiency fiber bundle technology.
Although the present invention has been described in detail with reference to the above embodiments, it is to be understood that the present invention is not limited to the details of the embodiments, and that other embodiments may be devised without departing from the spirit and scope of the present invention.
Claims (10)
1. The fiber bundle is characterized by comprising a modified fiber tow and a binder coating coated on the surface of the modified fiber tow, wherein the modified fiber tow is obtained by gathering modified fiber yarns, and the modified fiber yarns comprise a fiber yarn matrix and a surface auxiliary agent attached to the surface of the fiber yarn matrix.
2. The fiber bundle of claim 1, wherein the fiber bundle has a diameter of 0.1 to 5mm; the length of the fiber bundle is 5-60 mm; the ratio of the length to the diameter of the fiber bundle is (10-250): 1.
3. The fiber bundle of claim 1, wherein the binder comprises one or more of acrylic, phenolic, epoxy, latex, polyester, cellulose ether, vinyl ester, vinyl acetate, polyacrylamide, phosphate, polyurethane, and urea; the mass ratio of the binder to the fiber bundle is (1-100): 1000.
4. The fiber bundle of claim 1, wherein the fiber filaments are made of one or more of aramid, polyvinyl alcohol, polyester, glass, carbon, basalt, polypropylene, polyethylene, polyoxymethylene, polyamide, acrylic, natural fiber, ceramic and steel.
5. The fiber bundle of claim 1 or 4, wherein the number of filaments in each fiber bundle is 50 to 3000; the diameter of each single fiber filament is 5-200 mu m.
6. The fiber bundle of claim 1, wherein the surface auxiliary agent comprises one or more of oil, polyethylene glycol, silicate, dimethyl urea derivative, lithium chloride and butyl stearate; the mass ratio of the surface auxiliary agent to the fiber yarn is (5-65) to 1000.
7. A method for producing a fiber strand according to any of claims 1 to 6, comprising the steps of:
collecting a plurality of fiber filaments coated with the surface auxiliary agent on the surface to form fasciculate fibers;
and coating the outer surface of the fasciculate fiber with a bonding agent to obtain the fiber bundle.
8. Use of a fiber strand according to any one of claims 1 to 6 or a fiber strand produced by the production method according to claim 7 in a fiber-reinforced material.
9. A fiber-reinforced composite comprising a fiber bundle and a substrate; the fiber bundles are dispersed in the base material; the fiber bundle is the fiber bundle according to any one of claims 1 to 6 or the fiber bundle produced by the production method according to claim 7.
10. The fiber-reinforced composite of claim 9, wherein the substrate comprises one or more of cement, cement-based binders, polymers, ceramics, and metals.
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