Tape for concrete reinforcement

Abstract

A non-fibrillatable tape for concrete reinforcement is provided having a rectangular cross section, the tape having a length, a thickness and a width, wherein the width is larger than the thickness, the tape having a first major surface and a second major surface defined by the width of the tape and the length of the tape, and wherein the thickness of the tape is at most 125 µm and at least 50 µm, wherein the tape comprises embossments on at least the first major surface, wherein the embossments have a depth of at least 15 µm.

Description

[0001] Tape for Concrete Reinforcement

[0002] Description:

[0003] The invention pertains to tapes for concrete reinforcement.

[0004] Fiber reinforced concrete (FRC) is not a new concept. Since biblical times fibers were used in cementing construction materials in the form of straw and horsehair. In more recent times the asbestos fiber was used extensively in structural components like wall panels, roofs and gates. In the early 1960’s the health risk of manufacturing and using asbestos fibers became apparent and alternative fibers were introduced as a replacement.

[0005] After asbestos fibers, steel fiber was one of the first possible alternatives to steel bar reinforcing, with the first patent being applied for in 1874. It was however only in the early 1970’s that the use of these fibers on a large scale was noticed in the USA, Japan and in Europe.

[0006] Fibers are used in concrete to increase mechanical properties of concrete, to improve the volume stability of concrete, and to prevent cracking due to shrinkage of concrete. They also reduce the formation of drying and plastic shrinkage cracks to a minimum and improve concrete properties by increasing fire resistance, shock and impact resistance, and abrasion resistance of concrete.

[0007] Compared to steel fibers, synthetic fibers have the advantage of being non- corrosive, therefore being durable even in humid environments. Synthetic fibers, in particular polypropylene fibers, are used as fibers for concrete reinforcement, in particular in a concrete element which is subjected to compressive loads, such as for example concrete floor slabs applied on a subfloor, or in shotcrete applications. The synthetic fibers are generally applied to prevent, or at least reduce, the formation of cracks in the concrete and / or to increase the post-crack residual flexural tensile strength of the concrete, which enables to reduce post-crack deformation of the concrete.

[0008] Synthetic fibers can be applied to the concrete in various forms, for example as essentially round microfibers have an equivalent fiber diameter of at least 10 pm to about 300 pm, or as essentially round macrofibers have an equivalent fiber diameter of at least 300 pm, determined in accordance with EN14889, part 2.

[0009] Synthetic fibers can also be applied to the concrete as tapes having an essentially rectangular cross section defined by the thickness of the tape and the width of the tape, the width of the tape being larger than the thickness of the tape.

[0010] Synthetic tapes can be applied to improve the post-crack behaviour of concrete. They can replace steel mesh or steel fibres in some applications like ground supported floor slabs.

[0011] However, with tapes having a relatively large thickness, of for example 200 pm to 1000 pm, a satisfactory surface finishing of the concrete element reinforced by the tapes is not always obtained as the tapes having a relatively large thickness are found to stick out from surfaces of the concrete element.

[0012] With tapes having a relatively small thickness of below 150 pm, the reinforcement of the concrete element may not be satisfactory, in particular regarding the postcrack residual flexural tensile strength of the concrete element and / or the postcrack deformation of the concrete element.

[0013] US 2004 / 00258140 A1 discloses aliphatic polyester microfibers having an average effective diameter from 0.01 microns to 10 microns. Increasing the amount of synthetic tapes in the concrete generally reduces the formation of cracks in the concrete, and increases the post-crack residual flexural tensile strength of the concrete. However, a too high amount of synthetic tapes in the concrete hinders the workability of the concrete mixture thereby causing problems in handling the concrete mixture when forming a concrete element and / or deteriorating the quality of the concrete element.

[0014] There thus remains a need for improved tapes for concrete reinforcement which provide adequate surface finishing of the concrete element, while improving the reinforcement of the concrete element.

[0015] It is an object of the invention to a tape for concrete reinforcement which prevents, or at least reduces, at least some of the disadvantages of the prior art.

[0016] The object of the invention is achieved with the tape according to claim 1 . Advantageous further developments of the inventive tape are defined by the dependent claims.

[0017] A non-f ibri llatable tape for concrete reinforcement having a rectangular cross section, the tape having a length, a thickness and a width, wherein the width of the tape is larger than the thickness of the tape, the tape having a first major surface and a second major surface which are defined by the width of the tape and the length of the tape, and wherein the thickness of the tape is at most 125 pm and at least 50 pm, wherein the tape comprises embossments on at least the first major surface, wherein the embossments have a depth of at least 15 pm is provided.

[0018] Thin tapes for concrete reinforcement of the prior art have smooth surfaces. For example, US 6863969 B2 discloses fibers for concrete reinforcement having a generally quadrilateral cross-sectional profile with a thickness of less than 0.2 mm, but without any embossing on its surfaces.

[0019] Surprisingly, it has been found that a thin tape which comprises embossments having a relatively large depth in view of the thickness of the tape, i.e. embossments having a depth corresponding to at least 12% of the thickness of the tape, can be well dispersed in a concrete mixture, while still having a sufficiently high tensile strength and modulus despite the small effective thickness of the tape remaining at the location of the embossments, and to provide increased pull-out force of the tape, enabling to obtain improved post-crack residual flexural tensile strength of the concrete.

[0020] It has been observed that the tapes enable to provide adequate surface finishing of the concrete element by preventing, or at least reducing, tapes sticking out from surfaces of the concrete element.

[0021] The post-crack residual flexural tensile strength of concrete is determined, in accordance with test method EN 14845-2 “Test method for fibers in concrete, effect on concrete”, by a three-point bending test on a rectangular concrete beam having a length of 60 cm, a width of 15 cm and a height of 15 cm, the beam comprising a notch formed along the width and transversely to the length at the lower side of the beam. Load is applied on the upper side of the beam directly opposite to the notch. The vertical displacement and the strength at specified opening width of the notch, also known as crack mouth opening displacement or CMOD, are relevant characteristics of the tape reinforced concrete (FRC). In particular the strength at a CMOD of 0.5 mm (fR,i ) and at a CMOD of 3.5 mm (fR,4) are important characteristics of tape reinforced concrete. The CMOD of 0.5 mm (fR,i ) should be at least 1 .5 N / mm2and the CMOD of 3.5 mm (fR,4) should be at least 1 .0 N / mm2.

[0022] The dosage of the tapes in the concrete can be reduced at constant post-crack residual flexural tensile strength, which enables better handling, in particular the workability, of the concrete mixture.

[0023] The tape has a rectangular cross section, which is substantially uniform and constant along the length of the tape. As the tape having a rectangular cross section does not exhibit sudden changes in thickness across the width of the tape, the tape will not be subjected to locally high stress concentrations which increase the risk of initiating fibrillation of the tape into undesired smaller fibrous parts. The tape is therefore a non-fibrillatable tape. The thickness across the width of the tape preferably does not vary by more than 10% of the maximum thickness of the tape, more preferably by not more than 7.5%, even more preferably by not more than 5%, even more preferably by not more than 2.5% of the maximum thickness of the tape.

[0024] The tape has a width which is larger than the thickness of the tape, which enables to reduce the risk of individual tapes becoming entangled with one another. The non-fibrillatable tape preferably has a width to thickness ratio of at least 8, preferably at least 8.5, more preferably at least 10, preferably at least 12. The risk of individual tapes becoming entangled with one another is further reduced with increasing width to thickness ratio.

[0025] The non-fibrillatable tape preferably has a width to thickness ratio of at most 25, preferably at most 20, more preferably at most 15. The dispersibility of the non- fibrillatable tapes within a concrete element may become insufficient at a too high width to thickness ratio of the non-fibrillatable tapes and / or the amount of tapes spanning a crack in a concrete element may become too low to ensure prevention, or at least a reduction, of crack propagation.

[0026] The non-fibrillatable tape may have a width of at least 1.0 mm, preferably at least 1.1 mm, more preferably at least 1.2 mm, even more preferably at least 1.3 mm. The non-fibrillatable tape may have a width of at most 5.0 mm, preferably at most 4.0 mm, preferably at most 3.0 mm, preferably at most 2.0 mm, preferably at most 1.5 mm. In an embodiment, the non-fibrillatable tape may have a width of 1 .35 mm.

[0027] The non-fibrillatable tape may have a length in the range of 20 mm to 100 mm, preferably in the range of 30 mm to 70 mm, thereby providing sufficient post-crack residual flexural tensile strength in the tape reinforced concrete while preventing, or at least reducing, problems in handling the concrete mixture comprising the tapes, in particular the workability of the concrete mixture. The non-fibrillatable tape does not require shaping of the tape along its length into a non-linear shape to provide reinforcement of a concrete element. The non- fibrillatable tape is linear along the central axis in the length direction, which is understood to mean that the tape is not purposely shaped along its length into a non-linear shape, as would for example be the case in a wave-shaped tape.

[0028] The non-fibrillatable tape comprises embossments on at least the first major surface of the tape. The depth of the embossments is at least 15 pm, corresponding to at least 12% of the thickness of the tape at locations without embossments, which means that the remaining thickness of the tape comprising the embossments on the first major surface of the tape is at most 80% of the thickness of the tape at locations without embossments. The depth of the embossments may be at least 17.5 pm, or at least 20 pm, or at least 22.5 pm, or at least 25 pm to further improve the post-crack residual flexural tensile strength of concrete. The depth of the embossments may be at most 50 pm, or at most 40 pm, or at most 30.5 pm, to prevent, or at least reduce, the risk of inducing a too high level of mechanical stress in the non-fibrillatable tape.

[0029] Surprisingly, it has now been found that a thin tape having a thickness of at most 125 pm comprising embossments having a relatively large depth corresponding the thickness of the thin tape, i.e. corresponding to at least 12% of the thickness of the tape, still has a sufficiently high tensile strength and modulus to prevent, or at least reduce, the formation of cracks in a concrete element and / or to increase the post-crack residual flexural tensile strength of the concrete element, which enables to reduce post-crack deformation of the concrete, despite the small remaining effective thickness of the tape of at most 88% at the location of the embossments provided on the surface of the tape.

[0030] The non-fibrillatable tape may also comprise embossments having a depth of at least 15 pm on the second surface. Even in an embodiment wherein the tape comprises embossments on the first major surface of the tape and on the second major surface of the tape, the thin tape still has a sufficiently high tensile strength and modulus despite the small remaining effective thickness of the tape of at most 76%, or even less, at the location of the embossments on provided both major surfaces of the tape.

[0031] The non-fibrillatable tape may have a tensile strength of at least 500 MPa, preferably at least 550 MPa, more preferably at least 600 MPa, more preferably at least 625 MPa, even more preferably at least 650 MPa, determined according to EN 14889-2.

[0032] The non-fibrillatable tape may have a modulus of at least 6 GPa, preferably at least 7 GPa, more preferably at least 8 GPa, more preferably at least 9 GPa, even more preferably at least 9.5 GPa, determined according to EN 14889-2.

[0033] An embossment is understood to mean a depression in a surface of the tape, the depression having a particular shape.

[0034] The shape of the embossments provided on at least the first major surface of the tape may be varied, and in embodiments may be four-sided square pyramids, truncated four-sided square pyramids, cones, straight lines, ribs, wavy lines, square or rectangular blocks, hemispheres, or diamond-shaped.

[0035] The shape of the embossments provided on the second major surface of the tape may be varied, and in embodiments may be four-sided square pyramids, truncated four-sided square pyramids, cones, straight lines, ribs, wavy lines, square or rectangular blocks, hemispheres, or diamond-shaped.

[0036] The shape of the embossments provided on the second major surface of the tape may be the same as the shape of the embossments provided on the first major surface of the tape.

[0037] The shape of the embossments provided on the second major surface of the tape may also be selected independently and be different from the shape of the embossments provided on the first major surface of the tape. The embossments may have an area of at least 0.05 mm2per embossment, preferably at least 0.10 mm2per embossment, more preferably of at least 0.15 mm2, even more preferably of at least 0.20 mm2per embossment. The embossments may have an area of most 0.50 mm2per embossment, preferably of at most 0.40 mm2, more preferably of at most 0.35 mm2per embossment, even more preferably of at most 0.30 mm2per embossment. The embossments on the first major surface and / or on the second major surface of the tape have such a small scale as compared to the width of the tape that any localized thickness reduction by the embossments does not lead to high stress concentrations increasing the risk of initiating fibrillation of the tape into undesired smaller fibrous parts.

[0038] In a preferred embodiment, the embossments are diamond-shaped. The diamondshaped embossments may have a length of the sides in the range of 0.30 mm to 0.60 mm, preferably in the range of 0.35 mm to 0.55 mm, more preferably in the range of 0.40 mm to 0.50 mm.

[0039] The number and the spatial alignment of the embossments on a surface of the tape define a pattern of the embossments.

[0040] The shape of the embossments provided on the first major surface and / or the second major surface of the non-fibrillatable tape may be varied, and in embodiments may be straight lines oriented perpendicular to the length direction of the non-fibrillatable tape.

[0041] The shape of the embossments provided on the first major surface and / or the second major surface of the non-fibrillatable tape may be varied, and in embodiments may be straight lines oriented at an angle to the length direction of the non-fibrillatable tape, preferably at an angle of 30°, or preferably at an angle of 45°, or preferably at an angle of 60°, to the length direction of the non-f ibri llatable tape. The distance between repeating characteristic points of two consecutive embossments on an imaginary line oriented in the length direction of the tape, is called the pitch in length direction (PI). The distance between repeating characteristic points of two consecutive embossments on an imaginary line oriented in the width direction of the tape, is called the pitch in width direction (Pw).

[0042] The pattern of embossments may have a pitch in length direction of at least 0.6 mm, preferably of at least 0.8 mm, more preferably of at least 1 .0 mm, more preferably of at least 1.2 mm, even more preferably of at least 1 .4 mm, most preferably of at least 1.6 mm. The pattern of embossments may have a pitch in length direction of at most 3.0 mm, preferably of at most 2.5 mm, more preferably of at most 2.0 mm, in order to provide the non-fibrillatable tape with a number of embossments in the length direction allowing to further improve the post-crack residual flexural tensile strength of concrete.

[0043] The pattern of embossments may have a pitch in width direction of at least 0.4 mm, preferably of at least 0.5 mm, more preferably of at least 0.6 mm, more preferably of at least 0.7 mm, even more preferably of at least 0.8 mm, most preferably of at least 0.9 mm. The pattern of embossments may have a pitch in width direction of at most 1.2 mm, preferably of at most 1 .0 mm, in order to provide the non-fibrillatable tape with a number of embossments in the width direction allowing to further improve the post-crack residual flexural tensile strength of concrete.

[0044] The pattern of embossments may comprise at least 30 embossments per cm2, preferably at 40 embossments per cm2, more preferably at 50 embossments per cm2. The pattern of embossments may comprise at most 600 embossments per cm2, preferably at most 350 embossments per cm2, more preferably at most 250 embossments per cm2, more preferably at most 200 embossments per cm2, even more preferably at most 150 embossments per cm2, most preferably at most 125 embossments per cm2. The pattern of embossments may comprise the embossments in a rectangular pattern or in a staggered configuration.

[0045] A rectangular pattern is understood to mean a pattern wherein the embossments are imparted only along parallel lines oriented in the length direction of the tape which are spaced from each other by the distance of the pitch in width direction (Pw) and along parallel lines oriented in the width direction of the tape which are spaced from each other by the distance of the pitch in length direction (PI), as schematically shown in Figure 1 .

[0046] A staggered configuration is understood to mean a configuration wherein the embossments are imparted not only along parallel lines oriented in the length direction of the tape which are spaced from each other by the distance of the pitch in width direction (Pw) and along parallel lines oriented in the width direction of the tape which are spaced from each other by the distance of the pitch in length direction (PI), but wherein the embossments are additionally imparted along parallel lines oriented in the length direction of the tape which are shifted by half of the distance of the pitch in width direction (Pw) and shifted by half of the distance of the pitch in length direction (PI), as schematically shown in Figure 2.

[0047] The distance between repeating characteristic points of two consecutive embossments on an imaginary line oriented in the length direction of the tape, is called the pitch in length direction (PI). The distance between repeating characteristic points of two consecutive embossments on an imaginary line oriented in the width direction of the tape, is called the pitch in width direction (Pw).

[0048] The embossments on the first major surface may may have a cumulated depressed area of embossment of at least 15% of the first major surface, preferably at least 20%, more preferably at least 25%, even more preferably at least 30% of the first major surface. The embossments on the first major surface may may have a cumulated depressed area of embossment of at most 50% of the first major surface, preferably at most 45%, more preferably at most 40%, to prevent, or at least reduce, the risk of inducing a too high level of mechanical stress in the non-fibrillatable tape.

[0049] In an embodiment, embossments on the second major surface may have a cumulated depressed area of embossment of at least 15% of the first major surface, preferably at least 20%, more preferably at least 25%, even more preferably at least 30% of the first major surface. The embossments on the second major surface may may have a cumulated depressed area of embossment of at most 50% of the first major surface, preferably at most 45%, more preferably at most 40%, to prevent, or at least reduce, the risk of inducing a too high level of mechanical stress in the non-fibrillatable tape.

[0050] A non-fibrillatable tape having a rectangular cross section may be provided by a process comprising the steps of extruding a melt comprising one or more polymers through a spinneret comprising one or more capillaries to form one or more extruded tapes, each of the one or more capillaries being configured for providing a rectangular tape, cooling the extruded tapes, drawing the extruded tapes, preferably at a draw ratio of at least 10, to form the rectangular tapes for concrete reinforcement. Preferably, the process comprises the step of drawing the extruded tapes at a draw ratio of at least 11 , more preferably at a draw ratio of at least 12, even more preferably at a draw ratio of at least 13. Preferably, the process comprises the step of drawing the extruded tapes at a draw ratio of at most 25, more preferably at a draw ratio of at most 20, to prevent, or at least reduce, the risk of breakage of the tapes. Subsequently, the extruded, cooled and drawn tapes may be chopped to the desired length.

[0051] The embossments provided on the first major surface, and preferably on the second major surface, of the tape may be imparted to the extruded, cooled and drawn tapes prior to chopping to the desired length.

[0052] A non-fibrillatable tape having a rectangular cross section may advantageously be provided by supplying a film having a width larger than the tapes, orienting the film by stretching the film and dividing the film into multiple tapes of desired width, for example by cutting the film into tapes. Subsequently, the tapes may be chopped to the desired length.

[0053] The embossments provided on the first major surface, and preferably on the second major surface, of the tape may be imparted to the oriented film prior to slitting and chopping or may be imparted to the slit film (tapes) prior to chopping, but the embossments may also be imparted to the slit and chopped tapes.

[0054] The embossments provided on at least the first major surface of the tape may be imparted onto the tape by any suitable technique. The embossments provided on at least the first major surface of the tape may be imparted onto the tape by an embossing roll.

[0055] In an embodiment, the embossments provided on the first major surface and on the second major surface of the tape may be imparted onto the tape by a combination of two embossing rolls.

[0056] The embossing roll or the combination of two embossing rolls comprise the inverted shape of the individual embossments and the pattern of the embossments to be imparted on the first major surface of the tape, and optionally on the second major surface of the tape.

[0057] The non-fibrillatable tape may advantageously be composed for at least 50 wt.% of one or more polyolefin polymers, preferably for at least 60 wt.%, more preferably for at least 75 wt.%, even more preferably for at least 90 wt.%, of one or more polyolefin polymers, which are particularly suitable to resist the chemical conditions in a concrete mixture.

[0058] The non-fibrillatable tape is preferably composed for at least 50 wt.% of one or more polypropylene polymers, preferably for at least 60 wt.%, more for at least 75 wt.% of one or more polypropylene polymers.

[0059] The polypropylene polymer comprised in the tape according to the invention may be any polypropylene polymer. Preferably, the polypropylene polymer comprised in the tape has a melt flow index of 10 g / 10 min or less, preferably 5 g / 10 min or less, more preferably 3 g / 10 min or less, as determined in accordance with ISO 1133 at a temperature of 230°C and with a load of 2.16 kg, to further increase the tensile strength of the fiber.

[0060] The non-fibrillatable tape preferably comprises at least 5 wt.% of one or more polyethylene polymers, preferably for at least 10 wt.%, more preferably for at least 15 wt.% of one or more polyethylene polymers, in particular a high density polyethylene. The non-fibrillatable tape preferably comprises at most 90 wt.% of one or more polyethylene polymers, preferably for at most 80 wt.%, more preferably for at most 60 wt.% of one or more polyethylene polymers, in particular a high density polyethylene. In an embodiment, the tape comprises 80 wt.% of a polypropylene polymer and 20 wt.% of a high density polyethylene.

[0061] The polyethylene polymer comprised in the tape according to the invention may be any polyethylene polymer. Preferably, the polyethylene polymer comprised in the tape has a melt flow index of 5.0 g / 10 min or less, preferably 3.0 g / 10 min or less, more preferably 1.5 g / 10 min or less, preferably 1.0 g / 10 min or less, as determined in accordance with ISO 1133 at a temperature of 190°C and with a load of 2.16 kg, to further increase the tensile strength of the fiber. Preferably, the polyethylene polymer is a high density polyethylene polymer.

[0062] The non-fibrillatable tape may comprise an inorganic additive to increase adhesion of the fiber to concrete, the inorganic additive preferably being selected from the group consisting of calcium carbonate, calcium sulphate, talc and barium sulphate. Preferably, the tape may comprise 1 wt.% to 5 wt.% of inorganic additive. The amount of inorganic additive should not exceed 5 wt.% as this would increase the risk of forming pores in the tape, which could initiate fibrillation of the tape. In an embodiment, the tape excludes inorganic additives.

[0063] The non-fibrillatable tape does not require chemical surface modification for increasing interaction between the tape and a composition for forming a concrete element. In an embodiment, the tape excludes chemical surface modification of the first major surface and the second major surface of the tape. However, the surface of the non-fibrillatable tape comprising embossments having a depth of at least 15 pm on at least the first major surface may be modified, preferably by plasma treatment.

[0064] The non-fibrillatable tapes may be provided into a composition for forming a concrete element as individual tapes or may be provided as a packet of non- fibrillatable tapes. A packet of non-fibrillatable tapes comprises a plurality of tapes which are separably-bound together, such as by a film adhered to cut ends of the tapes, thereby forming a "packet." Within a wet composition for forming a concrete element, the packets could be made to break and / or dissolve apart to permit separation and dispersal of individual tapes within the composition.

[0065] The non-fibrillatable tape for concrete reinforcement according to the invention enables to reduce the amount of tapes in tape reinforced concrete without adversely affecting the properties of the concrete. The tape reinforced concrete may comprise the non-fibrillatable tapes in an amount of 10 kg / m3or less, preferably in an amount of 5 kg / m3or less, more preferably in an amount of 4 kg / m3or less, even more preferably in an amount of 3 kg / m3or less, most preferably in an amount of 2.5 kg / m3or less to prevent, or at least reduce, the risk of problems in handling the concrete mixture comprising the tapes, in particular the workability of the concrete mixture, and / or to improve the quality of the concrete element.

[0066] Example 1

[0067] A non-fibrillatable tape comprising 80 wt.% of a polypropylene and 20 wt.% of high density polyethylene was provided, the tape having a length of 32 mm, a thickness of 112 pm and a width of 1 .37 mm. The non-fibrillatable tape comprises diamondshaped embossments on the first major surface and on the second major surface of the tape, have a length of the sides of 0.5 mm. The embossments on the first major surface and on the second major surface of the tape have a depth of at least 16.2 pm. The pattern of embossments was provided in a staggered configuration, having pitch in length direction of 1.7 mm and a pitch in length direction of 1.0 mm.

[0068] The non-fibrillatable tape had a tensile strength of 580 MPa and a modulus of 8.7 GPa. The pull-out force was 41 .2 N corresponding to a pull-out force strength of 275 MPa and a pull-out work of 414 Nmm.

[0069] The crack mouth opening displacement of a concrete element comprising a dosage of 2.4 kg / m3of the non-fibrillatable tapes having a length of 32 mm was determined to be 1 .5 N / mm2at a CMOD of 0.5 mm (fR,i ) and 1 .4 N / mm2at a CMOD of 3.5 mm (fR,4).

[0070] Example 2

[0071] The crack mouth opening displacement of a concrete element comprising a dosage of 2.5 kg / m3of the non-fibrillatable tapes having a length of 32 mm of example 1 was determined to be 1.6 N / mm2at a CMOD of 0.5 mm (fR,i) and 1.6 N / mm2at a CMOD of 3.5 mm (fR,4).

[0072] Example 3

[0073] Non-fibrillatable tapes with embossments according to example 1 were provided, but having a length of 40 mm and having a linear density of 131 tex. The pull-out force was 51 .7 N and the pull-out strength was 360 MPa. Comparative example 1

[0074] A non-fibrillatable tape comprising 80 wt.% of a polypropylene and 20 wt.% of high density polyethylene was provided, the tape having a thickness of 108 pm and a width of 1 .35 mm.

[0075] The non-fibrillatable tape had a tensile strength of 606 MPa and a modulus of 9.0 GPa. The pull-out force was 19.5 N corresponding to a pull-out force strength of 135 MPa and a pull-out work of 257 Nmm.

[0076] The crack mouth opening displacement of a concrete element comprising a dosage of 3.0 kg / m3of non-embossed non-fibrillatable tapes having a length of 32 mm was determined to be 1.6 N / mm2at a CMOD of 0.5 mm (fR,i ) and 1 .8 N / mm2at a CMOD of 3.5 mm (fR,4).

[0077] Comparative example 2

[0078] The crack mouth opening displacement of a concrete element comprising a dosage of 3.2 kg / m3of non-embossed non-fibrillatable tapes having a length of 32 mm was determined to be 1.5 N / mm2at a CMOD of 0.5 mm (fR,i) and 1.5 N / mm2at a CMOD of 3.5 mm (fR,4).

[0079] Comparative example

[0080] Non-fibrillatable tapes without embossments were provided, but having a length of 40 mm and having a linear density of 130 tex. The pull-out force was 23.2 N, the pull-out strength was 164 MPa, and the pull-out work was 377 Nmm.

[0081] Although the tensile strength and the modulus of the non-fibrillatable tape of example 1 were lower than the tensile strength and the modulus of the tape of comparative example 1 , the pull-out force and the pull-out strength were more than 100% higher for the non-fibrillatable tape of example 1 , and the pull-out work was more than 60% higher.

[0082] Although the dosage of the non-fibril latable tapes in the concrete element of example 1 was reduced by 20%, the strength at a crack mouth opening displacement of 0.5 mm (fR,i ) is comparable to the strength of the concrete element of comparative example 1.

[0083] Although the dosage of the non-fibril latable tapes in the concrete element of example 1 was reduced by 20%, the strength at a crack mouth opening displacement of 3.5 mm (fR,4) is still well above the required lower level of 1 .0 N / mm2.

[0084] Although the dosage of the non-fibrillatable tapes in the concrete element of example 2 was reduced by 22%, the strength at a crack mouth opening displacement of 0.5 mm (fR,i ) is still higher than comparable to the strength of the concrete element of comparative example 2.

[0085] Although the dosage of the non-fibril latable tapes in the concrete element of example 2 was reduced by 22%, the strength at a crack mouth opening displacement of 3.5 mm (fR,4) is still higher than comparable to the strength of the concrete element of comparative example 2, and well above the required lower level of 1 .0 N / mm2.

[0086] The pull-out force of the non-fibrillatable tape with embossments was increased by 123% as compared to the non-fibrillatable tapes without embossments of comparative example 3. The pull-out strength of the non-fibrillatable tape with embossments was increased by 120% as compared to the non-fibrillatable tapes without embossments of comparative example 3. The pull-out work of the non- fibrillatable tape with embossments was increased by 28% as compared to the non-fibrillatable tapes without embossments of comparative example 3.

Claims

Tape for Concrete ReinforcementWhat is claimed is:1 . A non-fibrillatable tape for concrete reinforcement having a rectangular cross section, the tape having a length, a thickness and a width, wherein the width is larger than the thickness, the tape having a width of at least1 .0 mm, the tape having a first major surface and a second major surface defined by the width of the tape and the length of the tape, and wherein the thickness of the tape is at most 125 pm and at least 50 pm, wherein the tape comprises embossments on at least the first major surface, wherein the embossments have a depth of at least 15 pm.

2. The non-fibril latable tape for concrete reinforcement according to claim 1 , wherein the tape has a width of at most 5.0 mm.

3. The non-fibril latable tape for concrete reinforcement according to any one or more of the preceding claims, wherein the tape has a length of at least 20 mm and preferably at most 100 mm.

4. The non-fibril latable tape for concrete reinforcement according to any one or more of the preceding claims, wherein the tape comprises embossments having a depth of at least 15 pm on the second surface.

5. The non-fibrillatable tape for concrete reinforcement according to any one or more of the preceding claims, wherein the tape is composed for at least 50 wt.% of one or more polyolefin polymers.

6. The non-fibril latable tape for concrete reinforcement according to claim 5, wherein the tape is composed for at least 50 wt.% of one or more polypropylene polymers, preferably for at least 75 wt.% of one or more polypropylene polymers.

7. The non-fibril latable tape for concrete reinforcement according to any one or more of claims 5 to 6, wherein the tape comprises at least 5 wt.% of one or more polyethylene polymers, preferably for at least 10 wt.%, more preferably for at least 15 wt.% of one or more polyethylene polymers.

8. The non-fibrillatable tape for concrete reinforcement according to any or more of the previous claims wherein the tape has a tensile strength of at least 500 MPa, preferably at least 550 MPa, more preferably at least 600 MPa, even more preferably at least 625 MPa, most preferably at least 650 MPa, determined according to EN 14889-2.

9. The non-fibrillatable tape for concrete reinforcement according to any or more of the previous claims wherein the fiber has a modulus of at least 6 GPa, preferably at least 7 GPa, more preferably at least 8 GPa, more preferably at least 9 GPa, even more preferably at least 9.5 GPa, determined according to EN 14889-2.

10. A packet comprising a plurality of non-fibrillatable tapes according to any of the previous claims.

11. A concrete element comprising non-fibrillatable tapes according to any one or more of claims 1 to 9.

12. The concrete element according to claim 10 wherein the concrete element comprises the non-fibrillatable tape in an amount of 10 kg / m3or less, preferably 5 kg / m3or less, more preferably 4 kg / m3or less, even more preferably 3 kg / m3or less, most preferably 2.5 kg / m3or less.

13. A process for manufacturing a non-fibrillatable tape for concrete reinforcement comprising the steps of providing a tape having a rectangular cross section, the tape having a length, a thickness and a width, wherein the width is larger than the thickness, the tape having a width of at least 1 .0 mm, the tape having a first major surface and a second major surface defined by the width of the tape and the length of the tape, and wherein the thickness of the tape is at most 125 pm and at least 50 pm, and imparting embossments on at least the first major surface of the tape, wherein the embossments have a depth of at least 15 pm.

14. The process for manufacturing a non-fibrillatable tape for concrete reinforcement according to claim 13 comprising the step of imparting embossments on the second major surface of the tape, wherein the embossments have a depth of at least 15 pm.

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