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(11) | EP 4 567 217 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | COMPOSITE REBAR REINFORCED WITH WOVEN MESH AND CORD, RESPECTIVE PRODUCTION METHOD AND USES THEREOF |
| (57) The present description concerns a reinforced composite material rebar for reinforcing
concrete elements comprising: a core comprising fibres selected from glass fibres,
basalt fibres, carbon fibres or combinations thereof; a woven mesh covering the core
of the rebar; a thermosetting polymer matrix selected from polyester, epoxy or vinyl-ester,
or mixtures thereof; at least one cord wound helically around the woven mesh; wherein
the polymer matrix is impregnated into the woven mesh; wherein the woven mesh is selected
from polyester, biofibre or mixtures thereof. It also concerns a concrete structure
and the method of obtaining it.
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TECHNICAL FIELD
[0001] This description concerns a composite rebar reinforced with a woven mesh and a cord (helical structure), for incorporation into concrete parts or structures. The present description also concerns the method for obtaining the respective composite rebar.
BACKGROUND
[0002] In the construction industry, reinforced concrete structures are subject to the action of aggressive agents that cause a reduction in the mechanical resistance of the structures. This reduction in mechanical resistance compromises the behaviour and durability of these structures.
[0003] Corrosion, one of the main problems in concrete structures, jeopardises the performance of reinforced concrete elements, causing them to reach the limit state of use.
[0005] There has been a great deal of interest in the application of textile materials in composite materials for the construction industry. The application of fibres and yarns to reinforce the polymer matrix promotes optimisation of the developed product.
[0006] Patent document WO2008041204 describes a composite rebar reinforced by a braided textile structure, with axial reinforcement, based on the concept of multifunctional structures, where different types of fibres are used in different parts of the rebar, according to mechanical and physical requirements. These rebars allow for a rational distribution of the various types of fibres used, optimising their use, guaranteeing the required performance of the rebar and helping to reduce the costs associated with the production of steel rebars or lintels. Patent document WO2008041204, in its triaxial braiding production technique, integrates into the braiding machine a vat that allows the axial reinforcement fibres to be impregnated in a polymer matrix immediately before the braiding process. The production process takes place in a single step and the impregnation of the axially reinforced braided structure takes place from the inside to the outside of the structure.
[0007] A solution is now presented that is resistant to corrosion; has higher tensile strengths than construction steel; is lighter in weight than a steel rebar; is easy to transport and install; does not interfere with magnetic fields and/or radio frequencies; is electrically non-conductive; thermally non-conductive; has a higher melting point than steel and could allow monitoring and assessment of the condition of constructions.
[0008] These facts are described to illustrate the technical problem solved by the realisations of the present document.
GENERAL DESCRIPTION
[0009] The present description concerns a composite beam reinforced with a woven mesh interwoven with helical reinforcement. In particular, it concerns a rebar made of composite material axially reinforced with textile structures, intended for incorporation into concrete parts or structures. The rebar has superior reinforcement properties, providing greater strength and durability to concrete structures.
[0010] The present description relates to a rebar in composite material reinforced with a woven mesh and a cord (helical structure), for incorporation into concrete parts or structures. The present description also concerns the method for obtaining the composite rebar.
[0011] The composite rebar comprises a polymer matrix and continuous fibres and has several advantages over steel rebars, such as: greater specific strength, greater resistance to corrosion and fatigue, lower coefficient of thermal expansion, easier transport and installation and less environmental impact. In addition, the composite rebar has high durability and strength and is lightweight.
[0012] In one embodiment, the woven mesh comprises openings the size of which varies from 0.1mm to 5mm, preferably 0.5-3mm; more preferably 1 - 2mm.
[0013] In the scope of the present disclosure, the openings of the woven mesh (size/aperture size of the openings in the woven mesh), also referred to as "draft pattern of mesh", represent the intersection between warp and weft yarns in order to obtain a textile structure with a substantially square mesh-like design.
[0014] The present description concerns a reinforced composite rebar for reinforcing concrete elements comprising:
a core comprising selected fibres of glass fibres, basalt fibres, carbon fibres or
combinations thereof;
a woven mesh covering the core of the beam;
a thermosetting polymer matrix selected from polyester, epoxy or vinyl-ester, or mixtures thereof;
at least one cord wound helically around the woven mesh;
in which the polymer matrix is impregnated into the woven mesh;
wherein the woven mesh is made of polyester and/or biofibre (such as: cotton, silk, sisal, hemp; textile fibres derived from bamboo, soybean, or mixtures thereof, among others).
[0017] In one embodiment, the woven mesh comprises weft and warp yarns, whereby only part of the weft/web yarns pass over the cord in order to consolidate the cord to the rebar.
[0018] In a realisation, the rebar comprises two strands, wherein the first cord and the second cord are arranged in opposite directions, and which intersect at predetermined points.
[0020] In one embodiment, the weight of each monofilament of the plurality of monofilaments ranges from 800 DTex to 2000 DTex (80 Tex to 200 Tex), preferably 1000 - 1500 DTex (100 - 150 Tex), more preferably 1100 - 1300 DTex (120 - 130 Tex).
[0021] In one embodiment, the linear mass of the cord ranges from 5000-25000 DTex (500-2500 Tex), preferably 8000-20000 DTex (800-2000 Tex), more preferably 8000 - 15000 DTex (1000 - 1500 Tex).
[0022] In one realisation, the distance between the turns of the cord varies from 5-50mm, preferably 15-35mm.
[0024] In one embodiment, the amount of the polymer matrix is 10 to 70% (w/w); preferably 20 to 60% (w/w), more preferably 25 to 40% (w/w), more preferably 25 to 35% (w/w).
[0025] In one embodiment, the grammage of the polymer matrix is 10 to 70% (w/cm2 rebar); preferably 20 to 60% (w/cm2 rebar), more preferably 25 to 40% (w/cm2 rebar), more preferably 25 to 35% (w/cm2 rebar).
[0027] In one embodiment, the woven mesh comprises a plurality of textile fibres comprising from 5 to 200 filaments, preferably 10 to 190, more preferably 16 to 180 filaments.
[0028] In one embodiment, the textile fibre of the woven mesh comprises a total linear mass ranging from 100 DTex to 2000 DTex, preferably 500 to 1500 DTex, more preferably 800 to 1200 DTex.
[0030] In one embodiment, the number of filaments in the cord ranges from 8 to 35 multifilaments, preferably 13 multifilaments with 2 to 6 filaments each.
[0031] In one realisation, the size of the opening of the woven mesh ranges from 0.1-5mm; preferably 0.5-3 mm; more preferably 1 - 2 mm.
[0032] The present description further relates to concrete structures comprising the beam described.
[0033] The present description further relates to a method for obtaining the composite rebar described, comprising the following steps:
arranging a plurality of fibres selected from glass fibres, basalt fibres, carbon fibres or combinations thereof in a fibre feeder to create the core of the beam;
arranging a plurality of fibres to create the woven mesh;
impregnating the plurality of fibres of the core and the plurality of fibres of the woven mesh in the thermosetting polymer matrix;
braiding the plurality of fibres of the woven mesh with a braider and simultaneously winding at least one cord in a helical fashion around the woven mesh;
curing with thermal activation.
BRIEF DESCRIPTION OF THE FIGURES
[0035] For ease of understanding, the figures are attached, which represent preferred realisations that are not intended to limit the subject of this description.
Figure 1: Schematic representation of a realisation of the composite rebar.
Figure 2: Schematic representation of a realisation of the composite pole.
Figure 3: Schematic representation of a composite pole design comprising two strands wound helically around the woven mesh.
Figure 4: Schematic representation of a composite rebar design showing the core 1 comprising the reinforcement fibres and the woven mesh 2 corresponding to the braided covering fibres.
Figure 5: Schematic representation of a realisation of the method for obtaining the composite rebar.
Figure 6: Schematic representation of a realisation of the method for obtaining the composite rebar.
Figure 7: Schematic representation of the adhes area of a braided rebar.
DETAILED DESCRIPTION
[0036] The present description relates to a reinforced composite rebar comprising a core of reinforcing fibres, axially covered with a woven mesh, at least one cord arranged helically over the woven mesh and a polymer matrix.
[0037] The present article refers to an innovative rebar made of composite material axially reinforced with textile structures, which significantly improves the strength and durability of concrete parts and structures. The solution is unique due to the structure of the woven mesh in combination with the cord wrapped around the mesh.
[0040] In one embodiment, the diameter of the core of reinforcing fibres ranges from 1 to 60 mm, preferably from 2 to 50 mm, more preferably from 2.5 mm to 40 mm.
[0041] In one embodiment, the core comprises fibres selected from glass fibres, carbon fibres, basalt fibres or aramid fibres or mixtures thereof. Preferably, the core is made of glass fibres.
[0042] In one embodiment, each fibre of the core has a diameter of 0.1 to 1 µm, preferably 0.2 to 0.4 µm, more preferably 0.27 to 0.35 µm.
[0043] In one realisation, the rebar comprises 10 to 50 % (w/w) polymer matrix, preferably 20 to 35 % (w/w).
[0044] In one embodiment, the polymer matrix can be selected from epoxy, bio-epoxy, polyester or vinyl-ester. Preferably, the polymer matrix is epoxy or vinyl ester. The advantage of these materials is that they have a strong bond, durability, versatility and chemical and mechanical resistance.
[0045] In one embodiment, the interlaced woven mesh allows for homogenisation of the shape of the rebar and a surface roughness that will allow for excellent adhesion to the concrete.
[0046] In one embodiment, the woven mesh can have different geometries, in particular different plaiting angles or wires in its constitution.
[0047] In one embodiment, the braid comprises a plurality of symmetrically distributed fibres, which form the braid with half of the fibres having an angle and the other half having a symmetrical angle.
[0048] In one embodiment, the rebar comprises the woven mesh which has interlaced fibres with two symmetrical angles and the rebar further comprises a helical structure distributed axially along the rebar. The woven mesh gives the rebar a surface roughness.
[0049] In one embodiment, the interlacing can take place in a single layer or with a plurality of layers superimposed on each other in order to reinforce the rebar.
[0050] In one embodiment, the woven mesh is interwoven and is composed of fibres to axially reinforce the rebar and give roughness to the surface.
[0051] In one embodiment, the textile fibres of the woven interlaced mesh are selected from bio-fibres, polymer fibres, polyester or mixtures thereof.
[0053] In one embodiment, the textile fibre of the woven mesh comprises 5 to 200 filaments, preferably 10 to 190, more preferably 16 to 180 filaments.
[0054] In one embodiment, the textile fibre of the woven mesh has a total linear mass of between 100 Dtex and 2000 Dtex.
[0056] In one realisation, the cord is made of polyester, or of the other variants described in the yarn. The helical shape refers to a helical or spiral twist structure. The term helical implies that the cord, preferably a yarn, is twisted in the woven fabric in a helix or spiral pattern, which gives the rebar better results. This twisting structure affects the strength, elasticity and appearance of the rebar. This reinforcement makes the rebar more resistant and adheres better to the concrete.
[0057] In one embodiment, the cord has a torsional pitch ranging from 5 mm to 50 mm. In one realisation, the cord has a degree of twist between 5 and 50 turns/m.
[0058] The helical amplitude affects the properties of the rebar, including its strength and appearance.
[0059] In one embodiment, the rebar comprises a single spiral cord. Preferably, the winding angle is 30° to 70° with respect to the axial direction of the core, more preferably 35° to 60°.
[0060] In one embodiment, the rebar comprises two helical strands which are arranged in opposite directions, and which intersect at predetermined points. In particular, the first cord is spiralled around the core in one direction and the second cord is spiralled around the core in the opposite direction, so that the first and second strands intersect at certain points. Preferably, the first cord is clockwise and the second cord is anticlockwise. In one embodiment, the rebar comprises a simple spiral and a simple counter-spiral, i.e. 2 spirals crossed over each other.
[0062] In one embodiment, and for best results, part of the helically arranged cord is on the ribbed interwoven textile mesh and part of the cord is arranged under the ribbed interwoven textile mesh. More specifically, the ribbed interwoven textile mesh is over the cord at a spacing of 5 mm to 50 mm, preferably 10 to 35 mm.
[0063] In one embodiment, at certain points the cord is arranged under the ribbed interwoven textile mesh.
[0064] This combination of the cord being on or under the woven mesh results from the need to mechanically fix the cord and as a guarantee of stability, structural repeatability and application.
[0065] The present description also concerns a method for obtaining the composite rebar, which comprises the following steps:
arranging the core of glass fibres, basalt fibres, carbon fibres or mixtures thereof in a longitudinal alignment, in a continuous flow;
arranging a plurality of fibres to create the woven mesh that covers the core;
completely soak the fibres of the core, the fibres of the woven mesh and the cord of the helical structure in the polymer matrix, then remove the excess matrix;
start the pre-curing process with thermal activation;
braiding the woven mesh fibres to cover the core, creating a ribbed interwoven mesh;
simultaneously wind the cord in a helical fashion around the woven mesh;
start the final curing process by thermal activation;
after curing, carry out the cut-to-size process.
[0066] In one embodiment, the polymer matrix is applied at a temperature of 10 to 50°C, preferably 20 to 40°C. More preferably, the impregnation of the polymer matrix takes place at a temperature of 30 to 35°C.
[0067] In one embodiment, obtaining the rebar comprises the braiding being carried out by electrical equipment that allows the simultaneous rotation of several spools of high tenacity wire and that guarantees the coating of the pultruded composite.
[0068] In one embodiment, the braiding process uses 40 spools of polyester yarn, which are used in the head of the equipment. This braiding allows the outer surface of the cylindrical rebar to be suitably roughened and ensures that it significantly improves its adhesion to the concrete after the latter has been wrapped and cured.
[0069] The braiding technique is inexpensive to produce and allows the fibres to be oriented multiaxially in the plane, thus creating a ribbed structure that guarantees the protection and geometry of the core.
[0070] In one realisation, the method comprises braiding one or two systems of yarns in helical directions and simultaneously continuously stretching at constant speed the braid of said yarns.
[0071] In one embodiment, the method comprises the following steps:
feeding the fibres to obtain the core;
impregnating the fibres with the thermosetting matrix and transporting them to the braiding area;
braiding the impregnated fibres to form the woven mesh and winding at least one cord helically around the woven mesh;
conveyance to a curing chamber.
[0072] The impregnation of the fibres in the thermosetting polymer matrix takes place before the braiding, after which the composite is cured.
[0075] In the fibre feeding step, the fibres are unwound from the reels and guided to the fibre alignment plate, where there is a fibre dispersion module, then they go to a set of rollers designed to develop them and keep them under the right tension.
[0076] During the braiding of the fibres, the total excess resin present in the fibres that make up the core is finally removed due to the compression force caused by the polyester fibre, ensuring that the necessary amount of resin is incorporated into the rebars produced. The configuration of the braid present in the rebars can be controlled by adjusting the rotation speed of the braiding system.
[0077] In one embodiment, the curing chamber is at a pre-selected temperature to ensure the curing of the resin used during the rebar's residence time inside it. Excessive temperatures must be avoided to prevent the resin from degrading. However, the temperature of the chamber must be sufficient to ensure that the rebar acquires a solid consistency so that it can be pulled out of the oven in a controlled manner without any problems or damage caused by the pulling system.
[0079] Table 1 shows the experimental mechanical properties of example 1, an "X" type rebar in which the rebar comprises a core made up of a plurality of E, TEX 9600 glass fibre strands with a diameter of 6 mm, a high tenacity polyester coating with DTex 1100/192/1, TPM 5-50 S Twist. The angle of the mesh is approximately 49°, and the same angle for the helical cord. For the coating, 39 reels of the polyester were used, plus one reel filled with the cord that creates the rib. The preferred cord material is DTex 1100/192/1 high tenacity polyester, TPM 5-50 S Twist, and for the ribbing effect the cord was previously plaited with 8 strands.
[0080] The bars used have a length of 750 mm, in which 250 mm of each end were anchored to the steel tubes for the tensile test, thus leaving 250 mm of free length between ties.
Table 1 - Characterisation of the type X rebar and experimental mechanical properties
of the composite rebar of the present invention.
| Rebar characteristics | |
| Core material | Glass fibre multifilaments |
| Core diameter (mm) | 6mm |
| Mesh material | High tenacity polyester |
| Mesh angle (°) | 49 |
| Polymer matrix | Thermosetting |
| Degree of cord twist (°) | 49 |
| Mechanical properties | Value |
| Tensile strength (MPa) | 1368 |
| Maximum tensile deformation (%) | 6.28 |
| Tensile modulus of elasticity (GPa) | 79.3 |
| Density (g/cm3) | 2 |
[0081] The tests were carried out in accordance with the American Concrete Institute regulation ACI 440.3R -04: B.2 - "Guide Test Methods for Fiber-Reinforced Polymers (FRPs) for Reinforcing or Strengthening Concrete Structures". To do this, the inside of the tubes must be thoroughly cleaned before the rebar is inserted inside them.
[0082] The following table shows a comparison of a realisation of the composite rebar compared to a steel rebar.
Table 4 - Comparative table between a realisation of this description and a steel
rebar.
| Technical characteristics | Composite rebar of the present disclosure of type X | Steel rebar (A500NR) (comparative example) |
| Tensile modulus of elasticity - Young's modulus (GPa) | 79,3 | 210 |
| Flexural modulus of elasticity - Young's modulus (GPa) | 3,17 | 22,9 |
| Tensile tensile strength (MPa) | 1368 | 500-550 |
| Bending tensile strength (MPa) | 85 | 110 |
| Elongation - tensile (%) | 6,28 | 12 |
| Elongation - bending (%) | 2.7 | 0,62 |
| Density (g/cm3) | 2±0.2 | 8 |
| Coefficient of longitudinal thermal expansion (10^-6/°C) | 6-10 | 11 |
| Transverse thermal expansion coefficient (10^-6/°C) | 21-23 | 11 |
[0083] Tests carried out in accordance with the American Concrete Institute regulation ACI 440.3R -04: B.2 - "Guide Test Methods for Fiber-Reinforced Polymers (FRPs) for Reinforcing or Strengthening Concrete Structures.
[0084] Below is a table of example 2 showing the maximum stress obtained for a reference rebar, a rebar subjected to an alkaline environment and a rebar subjected to a chloride test.
[0085] The alkaline test environment was prepared in accordance with Procedure A, described in ASTM D7705/7705M-12 - Standard Test Method for Alkali Resistance of Fiber Reinforced Polymer (FRP) Matrix Composite Bars Used in Concrete Construction, which provides standardised requirements for determining the resistance of FRP bars to alkaline environments under laboratory conditions. The document suggests a chemical composition so that the solution represents the interstitial water inside Portland mortar concrete. Thus, the solution was prepared in 10 litres of distilled water, in a container measuring 85x45x15 cm, following the indications of compounds specified in the standard, namely: 1,185.0 g of Ca(OH)2, 9 g of NaOH and 42 g of KOH. The cycle times were 30, 60 and 80 days
[0086] To create the chloride environment, containers containing an aqueous solution of salt water were used, in which the test specimens were submerged. The saline solution was prepared in accordance with ASTM D 1141-98 - Standard Practice for the Preparation of Substitute Ocean Water, which specifies the chemical compounds to be associated in order to have an adequate representation of seawater. For preparation, the standard specifies that two compounds should be added to 9 litres of water: sodium chloride (245.34 g) and anhydrous sodium sulphate; and two solutions containing MgCl2. 6H2O (111.12 g), anhydrous CaCl2 (11.58 g) and SrCl2.6H2O (0.42 g) in solution 1; and KCl (6.95 g), NaHCO3 (2.01 g), KBr (1.0 g), H3BO3 (0.27 g) and NaF (0.03 g) in solution 2. The cycle times were 30, 60 and 80 days.
[0087] Several rebars were also tested: a reference "Y" type rebar which was subjected to an alkaline environment and a chloride environment.
[0088] In one case, the Y-type rebar comprised: a core diameter of 4 mm, in which the core comprised 75% (w/w) E glass fibre strands and 25% (w/w) 12K carbon fibres; the mesh comprised a high tenacity polyester coating with DTex 1100/192/1, TPM 5-50 S Twist; the mesh angle was approximately 49°, the same angle being used for the helical cord. For the coating, 39 coils were used with the aforementioned polyester plus one coil filled with the cord that creates the rib. The cord material is DTex 1100/192/1 high tenacity polyester, TPM 5-50 S Twist, and for the ribbing effect it was previously braided with 8 strands. The polymer matrix used was Biresin CR144 epoxy resin, approximately 30% (w/w).
[0089] The bars tested have a length of 750 mm, of which 250 mm at each end were anchored to the steel tubes for the tensile test, leaving 250 mm of free length between ties.
[0090] Tension can be measured by strain gauges or tension sensors.
Table 2 - Description of the maximum stresses found per sample, with "Y" type bars.
| Sample/Cycle | Maximum stress (MPa) | ||
| 1st Cycle (30 days) | 2nd Cycle (60 days) | 3rd Cycle (80 days) | |
| Reference "Y" type rebar | 1520,6 | 1520,6 | 1520,6 |
| Rebars subjected to alkaline environment of "Y" type | 1708,6 | 1522,4 | 1381,1 |
| Rebars subjected to chloride test of type "Y" | 1509,7 | 1387,5 | 1364,1 |
[0091] Tests carried out in accordance with the American Concrete Institute regulation ACI 440.3R -04: B.2 - "Guide Test Methods for Fiber-Reinforced Polymers (FRPs) for Reinforcing or Strengthening Concrete Structures.
[0092] There is a more marked reduction in the maximum stress of the bars subjected to the alkaline solution.
Table 3 - Description of the maximum modulus of elasticity found per sample
| Sample/Cycle | Modulus of elasticity [E] (MPa) | ||
| 1st Cycle (30 days) | 2nd Cycle (60 days) | 3rd Cycle (80 days) | |
| Reference "Y" type rebar | 100,4 | 100,4 | 100,4 |
| Rebars subjected to alkaline environment of "Y" type | 112,1 | 100,3 | 99,0 |
| Rebars subjected to chloride test of type "Y" | 104,3 | 95,5 | 93,7 |
[0093] Tests carried out in accordance with the American Concrete Institute regulation ACI 440.3R -04: B.2 - "Guide Test Methods for Fiber-Reinforced Polymers (FRPs) for Reinforcing or Strengthening Concrete Structures.
[0094] The bars were found to have good resistance to attack in basic environments, as the modulus of elasticity of the elements remained constant, close to the reference values.
[0095] A "Z" type rebar was also tested. The "Z" beam comprises: a core diameter of 4 mm, with a carbon fibre core; the mesh comprises a high tenacity polyester coating with DTex 1100/192/1, TPM 5-50 S Twist; the mesh angle is approximately 45°, and the same angle for the helical cord. The polymer matrix used was polyester, approximately 30% (w/w).
[0096] In one realisation, adhesion tests were carried out for the "Z" type composite rebar, in which the mesh comprises 16 polyester yarn spools.
[0097] This type of material was chosen because, in addition to the homogeneity and uniformity of the material, it has suitable properties in terms of flexibility and resistance to wear. Twelve types of roughness were selected, corresponding to variable meshing angles, drawing speed, diameter and roughness. Samples without roughness were also produced, varying only the drawing speed to serve as a control sample. Three types of speed were considered: (1) a so-called minimum speed - vmin (0.54 m/min); (2) a maximum speed - vmax (1.07 m/min) and (3) a speed considered to be intermediate between the speeds presented - vint (0.8 m/min). Four different roughness patterns were considered for each type of speed. Single braid roughness's were made with 8 and 16 strands, these multifilament strands being placed in one (1e) or two (2e) braid positions, producing one (1e) or two (2e) cord helicoids, respectively.
Table 5 - Characterisation of the samples tested according to the present invention,
namely the "Z" type rebar with one cord (1e) or two strands (2e).
| Sample name | Sample description | Speed (m/min) |
| 0evmin | Reels 1 to 16 multifilament polyester DTex 1100 | 0,54 |
| 0evmax | 1,07 | |
| 1evmax_8 | Reel 1- Braid consisting of 8 polyester multifilaments polyester DTex 1100 | 1,07 |
| 1evint_8 | 0,8 | |
| 1evmin_8 | Reels 2 to 16- polyester multifilament DTex 1100 | 0,54 |
| 2evmax_8 | Reels 1 and 9- Braid consisting of 8 polyester multifilaments polyester DTex 1100 | 1,07 |
| 2evint_8 | 0,8 | |
| 2evmin_8 | Reels 2 to 8 and 10 to 16- polyester multifilament DTex 1100 | 0,54 |
| 1evmax_16 | Reel 1- Braid consisting of 16 polyester multifilaments polyester DTex 1100 | 1,07 |
| 1evint_16 | 0,8 | |
| 1evmin_16 | Reels 2 to 16- polyester multifilament DTex 1100 | 0,54 |
| 2evmax_16 | Reels 1 and 9- - Braid consisting of 16 polyester multifilaments polyester DTex 1100 | 1,07 |
| 2evint_16 | 0,8 | |
| 2evmin_16 | Reels 2 to 8 and 10 to 16- polyester multifilament DTex 1100 | 0,54 |
[0098] From the pull-out tests carried out on the composite rebars embedded in two different types of mortar (RHP Plus and AREM Ciarga), carried out under the conditions shown in Table 5 and in accordance with standard EN 1015-11 (1999), it was concluded that sample "1evmax_8" was the one with the greatest force required for pull-out in the two mortars tested. As such, this type of rib is the one with the best results, being produced with just one coil that forms a helicoid around the woven mesh, the cord being an 8-strand DTex 1100/192/1 polyester twisted cord, TPM 5-50 S Twist.
[0099] In one embodiment, in the woven meshes produced there is a redistribution of forces and the formation of multiple cracks due to the fact that the fibres are composed of several filaments that do not break instantaneously. The presence of polyester ensures high levels of deformation at load levels of between 50 and 90% of the maximum load after the resistant fibres break due to its elastic capacity. In addition to better adhesion, the roughness of the rebars also promotes high levels of deformation, given that their spatial distribution is a helical shape which, when subjected to axial loads, elongates to high levels of deformation.
[0100] In one embodiment, Figures 1 and 2 represent the composite rebar in which 1 corresponds to the core of reinforcing fibres, 2 corresponds to the woven mesh and 3 corresponds to the cord which is arranged in a helical fashion.
[0101] In one realisation, Figure 3 represents a realisation of the composite rebar in which 3 corresponds to two strands. This figure shows the predetermined point at which the two strands cross.
[0102] In one embodiment, Figure 4 represents the composite rebar in which 1 corresponds to the core of reinforcing fibres and 2 is the woven mesh.
[0103] In one embodiment, Figure 5 shows a method for obtaining the composite rebar, where 7 is the braiding machine, 8 is the curing chamber, 11 is the fibre feed, 12 is the fibre impregnation, 13 is the braiding, 14 is the curing, 15 is the drawing, 16 is the core reinforcement fibres, 17 is the fibre alignment plate, 18 is the resin bath, 19 is the fibre orientation plate, 20 is the braiding reels, 21 is the braiding yarns and 22 is the motor.
[0104] In one embodiment, Figure 6 represents a method of obtaining the composite rebar in which 4 is the feeder for placing the fibres, 5 is the impregnation chamber where the fibres are impregnated, 6 is where fluidisation and pre-curing take place, 7 is the braider where the fibres are braided into the woven mesh, preferably a braiding machine, 8 is the curing chamber; 9 is the puller where pulling and cutting take place and 10 is the exit station.
[0105] In one embodiment, Figure 7 represents the grip area of a braided rebar. According to Figure 7, the distance X between the ribs represents the length of contact between the structure of the eight-strand braid, which will be responsible for the spacing between the filaments, and the letter Y represents the height of this same structure (roughness). These properties always depend on the structural properties of the braid, such as the braiding angle, the diameter of the core and the number of yarns used to create the roughness.
[0106] The term "comprises" or "comprising" when used herein is intended to indicate the presence of the features, elements, entireties, steps and components mentioned, but does not preclude the presence or addition of one or more other features, elements, integers, steps and components, or groups thereof.
[0107] The present invention is not, of course, in any way restricted to the realisations described herein and a person with average knowledge of the field will be able to envisage many possibilities for modifying it and replacing technical features with equivalent ones, depending on the requirements of each situation, as defined in the appended claims.
1. Reinforced composite material rebar for reinforcing concrete elements comprising:
a core (1) comprising fibres selected from glass fibres, basalt fibres, carbon fibres or combinations thereof;
a woven mesh (2) covering the core of the rebar;
a thermosetting polymer matrix selected from: polyester, epoxy or vinyl-ester, or mixtures thereof;
at least one cord (3) helically wound around the woven mesh;
wherein the polymer matrix is impregnated into the woven mesh,
wherein the woven mesh (2) is selected from polyester and/or biofibre.
2. Rebar according to the previous claim wherein the woven mesh (2) is made of polyester.
3. Rebar according to any one of the previous claims wherein the cord (3) has a degree
of twist between 5 to 50 turns/m.
4. Rebar according to any one of the claims wherein the woven mesh (2) comprises weft
yarns and warp yarns, wherein only part of the weft/warp yarns pass over the cord
in order to consolidate the cord to the rebar.
5. Rebar according to any one of the claims wherein the rebar comprises two cords (3),
wherein the first cord and the second cord are arranged in opposite directions, and
which intersect at predetermined points.
6. Rebar according to any one of the claims wherein the cord (3) comprises a plurality
of filaments, preferably monofilaments, more preferably the grammage of each monofilament
of the plurality of monofilaments ranges from 800 DTex to 2000 DTex, preferably 1000
- 1500 DTex, more preferably 1100 - 1300 DTex.
7. Rebar according to any one of the claims wherein according to any one of the preceding
claims wherein the linear mass of the cord (3) ranges from 5000-25000 DTex, preferably
8000-20000 DTex, more preferably 8000 - 15000 DTex.
8. Rebar according to any one of the claims wherein the distance between the turns of
the cord (3) varies from 5-50 mm, preferably from 15-35 mm.
9. Rebar according to any one of the claims wherein the amount of the polymer matrix
is from 10 to 70 % (w/w); preferably 20 to 60 % (w/w), more preferably 25 to 40 %
(w/w), more preferably 25 to 35 % (w/w) and/or the grammage of the polymer matrix
is from 10 to 70 % (w/cm2 rebar); preferably 20 to 60 % (w/cm2 rebar), more preferably 25 to 40 % (w/cm2 rebar), more preferably 25 to 35 % (w/cm2 rebar).
10. Rebar according to any one of the previous claims wherein the woven mesh (2) is a
ribbed interwoven structure, preferably the woven mesh (2) comprises a plurality of
textile fibres comprising from 5 to 200 filaments, preferably 10 to 190, more preferably
16 to 180 filaments.
11. Rebar according to the previous claim wherein the textile fibre of the woven mesh
(2) comprises a total linear mass ranging from 100 DTex to 2000 DTex, preferably 500
to 1500 DTex, more preferably 800 to 1200 DTex.
12. Rebar according to any one of claims 10 to 11 wherein each textile fibre of the woven
mesh (2) has a density of 2 to 8 (g/cm3).
13. Rebar according to any one of the previous claims wherein the woven mesh (2) has an
opening with a size ranging from 0.1-5mm; preferably 0.5-3 mm; more preferably 1 -
2 mm.
14. Concrete structures comprising the rebar according to any one of the previous claims.
15. Method of obtaining the composite rebar according to any one of claims 1 to 13 comprising
the following steps:
arranging a plurality of fibres selected from glass fibres, basalt fibres, carbon fibres or combinations thereof in a fibre feeder to create the core of the rebar (1);
arranging a plurality of fibres to create the woven mesh (2);
impregnating the plurality of fibres of the core and the plurality of fibres of the woven mesh in the thermosetting polymer matrix;
braiding the plurality of fibres of the woven mesh with a braider and simultaneously winding at least one cord (3) in a helical manner around the woven mesh;
curing with thermal activation.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description