Method for manufacturing a composite reinforcing bar

Abstract

The claimed invention relates to the field of building, and more particularly to composite reinforcing bar (rebar), and even more particularly to a method for manufacturing a composite fibre-reinforced plastic rebar that includes the following steps of: a. longitudinally drawing a strand of roving impregnated with a binder; b. applying to the drawn strand of binder-impregnated roving a helical wrapping comprised of bundles of binder-impregnated roving; c. applying to said helical wrapping longitudinal bundles of binder-impregnated roving; d. applying to said longitudinal bundles a helical wrapping comprised of bundles of binder-impregnated roving, said helical wrapping bundles being applied on top of the previously applied helical wrapping; e. repeating steps c and d until a prepreg of a rebar having the desired cross-sectional area is obtained; f. curing the obtained prepreg. The claimed invention further relates to a production line for manufacturing a composite fibre-reinforced plastic rebar using the aforementioned method. The claimed invention still further relates to a composite fibre-reinforced plastic rebar manufactured using the aforementioned method. The technical result is an increase in the shear resistance of the manufactured rebar.

Description

[0001] METHOD OF MANUFACTURING COMPOSITE REINFORCEMENT

[0002] DESCRIPTION

[0003] Field of technology to which the invention relates

[0004] The claimed invention relates to the field of construction, in particular to composite reinforcement, in particular, relates in its various aspects to a method for producing composite reinforcement, a production line for producing composite reinforcement and the composite reinforcement produced [E04C5 / 07, E04C5 / 00].

[0005] Composite reinforcement is used in building structures for reinforcing monolithic concrete and prefabricated buildings; for use in structural elements of buildings in the form of individual rods; for the manufacture of thermal insulation wall panels; for reinforcing concrete products (slabs, foundations) operating on an elastic base; for reinforcing the soil of the foundations of buildings and structures, including the foundations of highways and roads; for reinforcing asphalt concrete road surfaces; for anchoring retaining walls and structures in the ground.

[0006] State of the art

[0007] Currently, the use of composite reinforcement, such as fiberglass, basalt fiberglass or carbon fiber, instead of traditional metal reinforcement is widespread. The main advantages of composite reinforcement compared to metal reinforcement include increased corrosion resistance, low weight, identical to concrete thermal expansion coefficient, and low cost.

[0008] Regardless of the material of manufacture, reinforcement is a rod equipped with projections on its surface for adhesion to concrete. These projections experience the greatest load during the operation of the reinforced concrete element in tension and characterize the quality of adhesion of the reinforcement to concrete as a whole. The most widely known method for producing composite reinforcement is the method in which a rod prepreg is formed from bundles of roving impregnated with a binder, onto which bundles of roving impregnated with a binder are spirally wound in a spiral winding unit to form projections.

[0009] For example, the Russian patent “TECHNOLOGICAL LINE FOR MANUFACTURING COMPOSITE REINFORCEMENT” [RU2389853C1, published 20.05.2010] discloses: - a technological line for manufacturing composite reinforcement, containing a primary bundle pulling unit, two spiral winding units and a single curing / polymerization unit, located sequentially in the working direction;

[0010] - a method for producing composite reinforcement, in which a bundle formed from a plurality of bundles of roving impregnated with a binder is pulled in the longitudinal direction, a spiral winding of the roving impregnated with a binder is applied to the longitudinal bundle of roving impregnated with a binder in two successive spiral winding units, wherein in the second spiral winding unit a simultaneous multi-start spiral winding of the roving in the opposite direction is carried out, then the resulting reinforcement prepreg is cured; and

[0011] - composite reinforcement containing a central layer of longitudinally oriented roving and layers of spirally oriented roving, wherein the layers of spirally oriented roving are located in opposite directions.

[0012] In addition, the Russian patent “TECHNOLOGICAL LINE FOR MANUFACTURING COMPOSITE REINFORCEMENT” [RU2417889C1 published 10.05.2011] discloses:

[0013] - a process line for manufacturing composite reinforcement, considered as a prototype of the claimed invention, comprising a primary strand pulling unit, alternating blocks of a spiral winding unit, a curing chamber, a longitudinal roving feed unit and a curing chamber, arranged sequentially in the working direction; and

[0014] - a method for producing composite reinforcement considered as a prototype of the claimed invention, in which a bundle formed from a plurality of bundles of roving impregnated with a binder is pulled in the longitudinal direction, a spiral winding of bundles of roving impregnated with a binder is applied to the longitudinal bundle of roving impregnated with a binder, the resulting header is cured, longitudinal bundles of roving impregnated with a binder are applied to the applied spiral winding, the resulting header is cured, the stages of applying the spiral winding, curing, applying the longitudinal layer and curing are repeated.

[0015] As a prototype of the claimed composite reinforcement, the applicant considers “COMPOSITE REINFORCEMENT” [RU94594U1, published 05 / 27 / 2010], containing layers of longitudinal bundles, each of which is compacted by a transverse spiral winding.

[0016] The general disadvantage of the above-mentioned known methods, process lines and reinforcement is the low strength of the attachment of the projections to the rod in the manufactured reinforcement due to the small number of interlacings of the longitudinal and spiral bundles of roving, which results in the low resistance of the said projections to the shear force and, consequently, the low tensile strength of concrete products reinforced with such a reinforcement rod. The disordered alternation of the longitudinal and spiral windings contributes to the greater strength of the rod, but leads to the fact that only small sections of the interlacing of the spiral and longitudinal bundles of roving actually work on the resistance to the shear force and the resistance to the shear force is entirely determined by the strength of the attachment of the said winding to the previous layer.In addition, the disordered alternation of longitudinal and spiral windings ensures a small size of protrusions, which negatively affects the tensile strength of concrete products reinforced with such a reinforcing bar.

[0017] Disclosure of the essence of the invention

[0018] Taking into account the shortcomings of known analogues, the claimed invention in all its aspects is aimed at solving the technical problem of creating composite reinforcement with increased resistance to shear force, and, consequently, providing increased tensile strength of concrete products reinforced with such reinforcement.

[0019] When solving the above-mentioned problem, the invention in any of its aspects provides a general technical result, expressed in an increase in the resistance of the manufactured reinforcement to shear force.

[0020] The shear force is understood to be the force applied to the projections of the reinforcement essentially in the longitudinal direction or tangential direction, i.e., the direction of the extension of the reinforcement bar. The said shear force occurs, in particular, when stretching a concrete product reinforced with reinforcement, as well as when pulling out or pressing in the reinforcement. Since the tensile strength of a conventional reinforcement bar significantly exceeds the value of the maximum shear force, at which the integrity of the projections and the adhesion of the concrete and the projections of the reinforcement are preserved, it is the said maximum shear force that characterizes the tensile strength of the concrete product reinforced with the said bar and the resistance of the reinforcement to pulling out and pressing in.

[0021] The said technical problem is solved and the said technical result is achieved by creating a method for manufacturing composite reinforcement, which includes the following stages: a. a bundle of roving impregnated with a binder is pulled in the longitudinal direction, b. a spiral winding of bundles of roving impregnated with a binder is applied to the pulled bundle of roving impregnated with a binder, c. longitudinal bundles of roving impregnated with a binder are applied to the applied spiral winding, d. a spiral winding of bundles of roving impregnated with a binder is applied to the applied longitudinal bundles, wherein the said bundles of the spiral winding are applied over the previously applied spiral winding; e. stages c and d are repeated until a reinforcement prepreg with the required reinforcement cross-sectional area is obtained; f. the obtained prepreg is cured.

[0022] In particular, the cross-sectional area of ​​the bundle at stage a is no more than 30% of the required cross-sectional area of ​​the reinforcement.

[0023] In particular, the bundle at stage a is formed from one longitudinal bundle of roving.

[0024] In particular, the bundle at stage a is formed from a plurality of roving bundles.

[0025] In particular, in step c, bundles of binder-impregnated roving are attached to the prepreg in a substantially uniform distribution around its circumference.

[0026] In particular, at each subsequent stage, a greater number of longitudinal bundles of roving are attached.

[0027] The specified technical problem is solved and the specified technical result is achieved by creating a technological line for manufacturing composite reinforcement in the above-mentioned manner, containing a primary strand drawing unit, alternating spiral winding units and longitudinal roving feed units, and a single curing unit, all located sequentially in the working direction.

[0028] In particular, the primary bundle pulling unit is designed with the possibility of forming a bundle with a cross-sectional area of ​​no more than 30% of the required cross-sectional area of ​​the reinforcement.

[0029] In particular, the primary bundle pulling unit is designed with the possibility of forming a bundle from one longitudinal bundle of roving.

[0030] In particular, the primary bundle pulling unit is designed with the possibility of forming a bundle from a plurality of bundles.

[0031] In particular, the longitudinal roving feed unit is designed with the possibility of attaching roving bundles impregnated with a binder with a substantially uniform distribution around the circumference of the prepreg.

[0032] In particular, each subsequent longitudinal roving feed unit is designed with the possibility of attaching a greater number of longitudinal roving bundles than the previous one in the working direction.

[0033] The said technical problem is solved and the said technical result is achieved by creating composite reinforcement, manufactured by the above-mentioned method, containing layers of spiral winding of roving and layers of longitudinally oriented roving, wherein the said layers alternate with each other in the direction of the reinforcement thickness, while the layers of spiral winding are located one above the other in the radial direction of the reinforcement.

[0034] In particular, the cross-sectional area of ​​the central layer of longitudinally oriented roving is no more than 30% of the cross-sectional area of ​​the reinforcement.

[0035] In particular, the roving bundles in the spirally oriented roving layer are substantially uniformly distributed around the circumference of the reinforcement.

[0036] In particular, each subsequent layer of longitudinally oriented roving in the radial direction contains a greater number of longitudinal roving bundles.

[0037] Brief description of the drawings

[0038] Fig. 1 schematically shows the first example of the implementation of the claimed technological line for the production of composite reinforcement;

[0039] Fig. 2 schematically shows a second example of the implementation of the claimed technological line for the production of composite reinforcement; Fig. 3 shows a block diagram of the claimed method for producing composite reinforcement; Fig. 4 shows the claimed composite reinforcement in longitudinal section.

[0040] The following are marked on the drawings: 1 - roving spool; 2 - primary roving bundle pulling unit; 3 - roving spiral winding unit; 4 - reinforcement prepreg; 5 - roving longitudinal feed unit; 6 - curing unit; 7 - finished reinforcement; 8 - longitudinal bundle formation unit; 9 - roving spiral winding layer; 10 - roving longitudinal winding layer; 11 - rod; 12 - projections.

[0041] Implementation of the invention

[0042] The following is a description of examples of the implementation of three aspects of the claimed invention.

[0043] Technological line for the production of composite reinforcement

[0044] Fig. 1 shows the claimed process line for manufacturing composite reinforcement, comprising a plurality of roving spools 1, a primary roving tow pulling unit 2 configured to feed a primary tow of roving impregnated with a binder, roving spiral winding units 3 configured to wind bundles of roving impregnated with a binder onto a reinforcement prepreg 4 passing through them at an angle to the working direction, roving longitudinal feed units 5 configured to attach bundles of roving impregnated with a binder onto a reinforcement prepreg 4 passing through them, as well as a curing unit 6 configured to cure the reinforcement prepreg 4 passing through it to form a finished cured reinforcement 7. In this case, the roving spiral winding units 3 and the roving longitudinal feed units 5 alternate with each other in the working direction.

[0045] The longitudinal or working direction is understood to mean the main direction of movement of the prepreg reinforcement from the primary bundle pulling unit 2 to the curing unit 6.

[0046] Prepreg is an uncured reinforcement blank made from interwoven bundles of roving impregnated with an uncured binder.

[0047] Roving is a bundle of continuous non-metallic fiber threads, such as aluminoborosilicate glass fibers, basalt fibers or carbon fibers with a thickness of 10-20 microns, and has a density of 200 to 9600 tex. A roving bundle is a plurality of continuous glass fiber threads, depending on the number of threads, has a density of 200 to 9600 tex. A roving bundle is formed from at least one roving bundle.

[0048] In the example shown in Fig. 1, the primary roving bundle pulling unit 2 is designed with the possibility of forming a bundle from a plurality of roving bundles, the total cross-sectional area of ​​which is no more than 30% of the required reinforcement cross-sectional area. This embodiment example reduces the number of required units 3 and 5 for forming a prepreg of the required cross-sectional area without compromising the value of the resistance of the projections to the shear force, which was established experimentally for the above-mentioned value of the primary bundle area of ​​30% of the required reinforcement cross-sectional area.

[0049] The required cross-sectional area is understood to be the pre-set cross-sectional area of ​​the finished reinforcement, for the production of which the production line is configured, in particular, having a sufficient number of winding units 3 and 5 to form a prepreg with the specified pre-set cross-sectional area.

[0050] In the example shown in Fig. 2, the primary roving bundle pulling unit 2 is designed with the possibility of forming a bundle from a single roving bundle. This embodiment example, although it increases the number of required units 3 and 5 for forming a prepreg of the required cross-sectional area, provides an additional increase in resistance to shear force, since it maximizes the number of roving bundle interlacings in the rod.

[0051] The roving spiral winding unit 3 is a frame which is designed with the possibility of rotation around the prepreg passing through the said unit and winding bundles of roving onto the said prepreg, for which purpose it contains roving spools 1, as shown in Figs. 1 and 2.

[0052] The spiral winding units 3 are designed with the possibility of winding roving bundles onto the prepreg passing through them with the same pitch and angle so that it is possible to wind each subsequent bundle over the bundles wound in the previous spiral winding unit.

[0053] The arrangement on top means the arrangement of each subsequent layer of spiral winding above the previous one in the radial direction of the prepreg, as clearly shown in Fig. 4.

[0054] Winding the bundles of spiral winding over the bundles wound in the previous spiral winding unit ensures a fast and concentrated increase in the height of the reinforcement projections without unnecessary waste of roving.

[0055] In the examples of the embodiment of the claimed process line shown in Fig. 1 and 2, the longitudinal roving feed units 5 are designed with the ability to receive a roving bundle from the corresponding longitudinal roving bundle formation units 8, designed with the ability to form a roving bundle from roving bundles fed from roving spools, and to divide it into separate bundles for fastening to the surface of the prepreg of the manufactured reinforcement, extending in the working direction. Nevertheless, an example of embodiment is also possible in which each longitudinal roving feed unit 5 is supplied with roving bundles directly from individual roving spools 1.

[0056] The longitudinal roving feed unit 5 is preferably designed with the possibility of attaching the roving bundles impregnated with a binder with a substantially uniform distribution around the circumference of the prepreg, that is, with a substantially equal angular distance between the bundles being attached.

[0057] The specified uniform fastening of longitudinal roving bundles contributes to greater strength due to greater uniformity of overlapping of roving bundles in the prepreg.

[0058] Preferably, each subsequent longitudinal feed unit 5 among the provided longitudinal feed units is designed with the possibility of attaching a larger number of longitudinal roving bundles. For example, the first longitudinal feed unit 5 is designed with the possibility of attaching three bundles, the second - six, the third - nine, and the fourth - twelve.

[0059] The increase in the number of attached roving bundles in the longitudinal winding units 5 is due to the increase in the cross-sectional area of ​​the prepreg as it moves through units 3 and 5 in the working direction. The curing unit 6 is a chamber extended in the working direction, made with the possibility of heating the prepreg passing through it in the working direction to the curing temperature of the binder, preferably to 100-250 degrees Celsius, to form the finished reinforcement. In the case of using thermoplastic polymers as a binder, the curing unit 6 ensures the amorphous state of the thermoplastic. After cooling, the prepreg of the reinforcement passes into a crystalline state. Preferably, the curing unit 6 contains two chambers, the working temperature in which is 100-130 and 150-250 degrees Celsius, respectively.

[0060] The implementation of a process line with a single curing unit 6, located after all units 3 and 5 for winding roving in the working direction, provides the possibility of a single curing of the prepreg to form finished reinforcement, which ensures energy savings spent on the manufacture of reinforcement, and also increases the strength of the product, since it ensures the curing of the product as a whole, rather than the joining of various cured layers to each other.

[0061] The image of the process line is schematic and is given with a generalization, appropriate for explaining various aspects of the claimed invention, and does not contain an image of elements and units that are not related to the essence of the invention. At the same time, the absence of elements and units in the image does not mean their absence in the claimed process line. Thus, for example, the drawings do not show the unit for impregnating the roving with a binder, while it is obviously present in the invention. The unit for impregnating the roving can be implemented in any known and prior art way - for example, in the form of an impregnation bath through which the roving bundles are passed before feeding to units 3 and 5 or in the form of dispensers associated with each roving spool or units 3 and 5 and made with the possibility of impregnating the outgoing roving bundle.

[0062] The binder is intended for fastening roving bundles and roving threads inside the bundle and is mainly a thermosetting resin (polyester, phenol-formaldehyde, epoxy, polyimide, polyester or organosilicon), or heat-resistant thermoplastic (aromatic polyamides, polysulfones, polycarbonates), or low-melting thermoplastics such as polyolefins, PVC, PET. The use of secondary thermoplastic polymers can significantly reduce the cost of production. The use of reinforcement on a thermoplastic binder is possible in road construction, low-rise, where the operating temperature does not exceed 50 degrees Celsius. Method of manufacturing composite reinforcement

[0063] As shown in Fig. 2, the claimed method for producing composite reinforcement includes the following sequentially performed steps: a. impregnating a longitudinal roving tow with a binder and pulling it in the longitudinal direction through a primary roving tow pulling unit 2, b. applying a spiral winding of bundles of binder-impregnated roving to a longitudinal bundle 3 of roving impregnated with a binder exiting from the primary roving tow pulling unit 2 in a roving spiral winding unit 3, c. applying longitudinal bundles of binder-impregnated roving to the applied spiral winding in a roving longitudinal feed unit 5, d. applying a spiral winding of bundles of binder-impregnated roving to the applied longitudinal bundles in a roving spiral winding unit 3, wherein said bundles of the spiral winding are applied over the previously applied spiral winding; e. if the cross-sectional area of ​​the prepreg after completion of step d is less than required, repeat steps c and d; f.the obtained prepreg is cured in curing unit 6 to obtain finished composite reinforcement.

[0064] In the process line in Fig. 1, steps c and d are repeated once.

[0065] The creation of a periodic structure of composite reinforcement is ensured by the drive for pulling the reinforcement prepreg at different speeds, that is, at the place of thickening / protrusion, a short-term slowdown of the pulled prepreg occurs, which ensures the profile of the manufactured reinforcement.

[0066] Fig. 2 shows a minimal process line intended for implementing the claimed method. The depicted process line contains a unit 2 for drawing the primary roving bundle (implements stage a), a unit 3 for spiral winding at the outlet of said unit (implements stage b), one pair of a unit 5 for longitudinal feed and a unit 3 for spiral winding of roving (implements stages c and d once), as well as a curing unit (implements stage f).

[0067] Winding the bundles of spiral winding over the bundles wound in the previous spiral winding unit ensures a fast and concentrated increase in the height of the reinforcement projections without unnecessary waste of roving.

[0068] In particular, at step a, the longitudinal strand can be formed from a plurality of roving bundles. Preferably, the cross-sectional area of ​​the longitudinal strand does not exceed 30% of the required cross-sectional area of ​​the reinforcement. As a result, the number of repetitions of the end steps is reduced to achieve the required cross-sectional area of ​​the prepreg without compromising the value of the resistance of the protrusions to the shear force, which was experimentally established for the above-mentioned value of the primary strand area of ​​30% of the required cross-sectional area of ​​the reinforcement.

[0069] In particular, in step a, the longitudinal strand can be formed from a single bundle of roving. As a result, although the number of repetitions of the end steps to achieve the required cross-sectional area of ​​the prepreg is increased, an additional increase in shear resistance is provided, since the number of interlacings of roving bundles in the reinforcement is maximized.

[0070] Preferably, at the bundling stage, the binder-impregnated roving is attached to the prepreg with a substantially uniform distribution around its circumference, i.e., with a substantially equal angular distance between the attached bundles.

[0071] In this application, the feature “essentially” implies the possibility of deviation from the specified value or characteristic by no more than 2%, that is, the feature “essentially uniform distribution around the circumference” implies uniform distribution with the possibility of angular deviation of no more than 2%, that is, no more than 7.2 degrees (2% of 360 degrees).

[0072] The specified uniform fastening of longitudinal roving bundles contributes to greater strength of the manufactured reinforcement due to greater uniformity of overlapping of roving bundles in the prepreg.

[0073] Preferably, at each subsequent stage, a greater number of longitudinal roving bundles are attached. For example, at the first stage, three bundles are attached, at the second stage, six, at the third stage, nine, and at the fourth stage, twelve.

[0074] The increase in the number of attached roving bundles in longitudinal winding nodes 5 is due to the increase in the cross-sectional area of ​​the prepreg as it moves through nodes 3 and 5 in the working direction.

[0075] The single curing of the prepreg at step f to form the finished reinforcement provides savings in the energy spent on the manufacture of the reinforcement, since it eliminates the need to feed multiple curing units, and also increases the strength of the product, since it ensures the curing of the product as a whole, that is, as a single unit, and not the joining of various cured layers to each other.

[0076] Composite reinforcement

[0077] As shown in Fig. 4, the claimed composite reinforcement comprises layers 9 of spiral winding of roving (oblique hatching) and layers 10 of longitudinal winding of roving (horizontal hatching), wherein said layers alternate with each other in the direction of the reinforcement thickness, wherein the layers of spiral winding are located one above the other in the radial direction of the reinforcement. In this case, the layers superimposed on each other form a rod 11 and projections 12 on it.

[0078] A layer is understood to be a plurality of roving bundles having the same orientation - longitudinal or spiral, while the specified plurality of bundles does not necessarily cover the entire surface of the underlying layer.

[0079] In this case, section I in Fig. 4 corresponds to the initial roving bundle, section II corresponds to the prepreg that has passed through unit 3 of the spiral winding of the roving, section II corresponds to the prepreg that has passed through unit 3 of the spiral winding of the roving and unit 5 of the longitudinal feed of the roving, section III corresponds to the prepreg that has passed through two units 3 of the spiral winding of the roving and one unit 5 of the longitudinal feed of the roving, and section IV corresponds to the prepreg that has passed through 2 units 3 of the spiral winding of the roving and unit 5 of the longitudinal feed of the roving.

[0080] As can be seen in Fig. 4, with each new layer the number of intersections in the area of ​​the projections 12 increases with arithmetic progression, which ensures an increase in the strength of the fastening of the projections 12 to the rod 11, that is, an increase in the resistance of the projections 12 to the shear force.

[0081] Resistance of reinforcement to shear force

[0082] In order to verify in practice the useful technical effect of increasing resistance to shear force, the applicant carried out the following tests. Four concrete cylinders with a diameter of 10 cm and a length of 30 cm, reinforced with composite reinforcement with the same cross-section of 0.9 mm, were manufactured. 2 , but with different designs - reinforcement A, B, C, G, D. The reinforcement bars were 30 cm long and were immersed in concrete mortar by 20 cm so that 10 cm of the bar protruded from the concrete product.

[0083] In the production of reinforcement A, spiral roving was wound onto a longitudinal bundle of multiple roving bundles until protrusions were formed, and curing was carried out for the entire prepreg as a whole.

[0084] In the production of reinforcement B, spiral roving was wound onto a longitudinal bundle of multiple roving bundles, the prepreg was cured, a layer of longitudinal roving bundles was applied to the cured prepreg, cured, and the stages of applying spiral winding, curing, applying a longitudinal layer, and curing were repeated until a.

[0085] Reinforcement B was manufactured in a similar manner to reinforcement B, with the only difference being that the spiral winding was applied over the previously applied spiral winding.

[0086] The G reinforcement was manufactured using the stated method - that is, by superimposing spiral windings on top of each other, using a thermosetting binder and final curing at the end of the prepreg manufacturing process.

[0087] Reinforcement D corresponds to reinforcement G and differs only in the use of a thermoplastic binder instead of a thermosetting one.

[0088] The concrete cylinders were aged for 28 days after the concrete was poured and subjected to a reinforcement pull-out test to determine the force required for the reinforcement to extend out of the cylinder by more than 10 mm.

[0089] The least tear-out force was found in the cylinder with reinforcement A, the value of the tear-out force for this reinforcement was taken as a conventional unit. The test results are summarized in the following table 1.

[0090] Table 1 - Test results of reinforced concrete cylinders

[0091] Moreover, during the tests of reinforcement G and D, when the pull-out force of 2.55 conventional units was reached, the rod did not exit the concrete cylinder, but the reinforcement itself was destroyed, that is, for these types of reinforcement, the pull-out force was at least equal to the tensile strength of the rod itself.

[0092] As was indicated above, in the known types of reinforcement, the shear force significantly exceeds the tensile strength of the reinforcement itself. Experimental data regarding rods G, D showed that in the claimed solution, the resistance to the shear force is at least equal to the tensile strength of the reinforcement. This useful effect is provided precisely by the configuration of the winding and roving and does not depend on the selected binder, as the experiment showed in terms of rods G and D. Indeed, in the disclosed configuration, the entire reinforcement structure works to resist the shear force, and not only the attached spiral protrusions, the strength of which is entirely determined by the properties of the binder that attaches the said protrusions to the supporting rod, as in the known solutions.As can be seen from the results of the experiment, the reinforcement with a thermosetting binder and a thermoplastic binder demonstrated the same resistance to shear force, given that the thermoplastic binder is known to specialists for providing significantly lower strength during curing compared to the thermosetting binder. Considering the significantly lower cost of the thermoplastic binder, the present invention also provides an advantage expressed in eliminating the dependence of the shear force resistance of the reinforcement on the choice of the type of binder, which makes it possible to use a cheaper thermoplastic binder without losing the strength and resistance to shear force of the resulting reinforcement.

Claims

FORMULA 1. A method for producing composite fiberglass reinforcement comprising the following steps: a) pulling a bundle of roving impregnated with a binder in the longitudinal direction, b) applying a spiral winding of bundles of roving impregnated with a binder to the pulled bundle, c) applying longitudinal bundles of roving impregnated with a binder to the applied spiral winding, d) applying a spiral winding of bundles of roving impregnated with a binder to the applied longitudinal bundles, wherein said bundles of spiral winding are applied only over the previously applied bundles of spiral winding; e) repeating steps c) and d) until a reinforcement prepreg with the required reinforcement cross-sectional area is obtained; f) curing the obtained prepreg.

2. The method according to claim 1, wherein the cross-sectional area of the bundle at step a) is no more than 30% of the required cross-sectional area of the reinforcement.

3. The method according to claim 1, wherein the bundle in step a) is formed from one longitudinal bundle of roving.

4. The method according to claim 1, wherein the bundle in step a) is formed from a plurality of bundles of roving.

5. The method according to claim 1, wherein in step c) the bundles of binder-impregnated roving are applied to the prepreg with a substantially uniform distribution around its circumference.

6. The method according to claim 1, wherein at each subsequent step c) a greater number of longitudinal bundles of roving are applied.

7. A process line for manufacturing composite fiberglass reinforcement by the method according to item 1, comprising a primary strand pulling unit, alternating spiral winding units and longitudinal roving feed units, and a single curing unit, arranged sequentially in the working direction, wherein the spiral winding units are designed with the possibility of winding roving bundles onto a prepreg passing through them with the same pitch and angle so that it is possible to wind each subsequent bundle only over the bundles wound in the previous spiral winding unit.

8. The line according to item 7, in which the primary bundle pulling unit is designed with the possibility of forming a bundle with a cross-sectional area of no more than 30% of the required cross-sectional area of the reinforcement.

9. The line according to item 7, in which the primary bundle pulling unit is designed with the possibility of forming a bundle from one longitudinal bundle of roving.

10. The line according to I.7, in which the primary bundle pulling unit is designed with the possibility of forming a bundle from a plurality of bundles.

11. The line according to item 7, in which the longitudinal roving feed unit is designed with the possibility of applying bundles of roving impregnated with a binder with a substantially uniform distribution over the circumference of the prepreg.

12. The line according to item 7, in which each subsequent longitudinal roving feed unit is designed with the possibility of applying a greater number of longitudinal roving bundles than the previous one in the working direction.

13. Composite fiberglass reinforcement manufactured by the method according to item 1, containing layers of spirally wound roving and layers of longitudinally oriented roving, wherein said layers alternate with each other in the direction of the reinforcement thickness, wherein the layers of spiral winding are located only one above the other in the radial direction of the reinforcement.

14. Reinforcement according to item 13, in which the cross-sectional area of the central layer of longitudinally oriented roving is no more than 30% of the cross-sectional area of the reinforcement.

15. The reinforcement according to claim 13, wherein the bundles in the layer of spirally oriented roving are substantially uniformly distributed around the circumference of the reinforcement.

16. The reinforcement according to item 13, in which each subsequent layer of longitudinally oriented roving in the radial direction contains a greater number of longitudinal bundles of roving.

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