CONCRETE MIX DESIGNS USING A PLURALITY OF REINFORCEMENT FIBERS SYSTEMS

Abstract

A concrete mix having sand, fine aggregates, binder, fibers, and various admixtures is provided. The mix has a consistency from S2 to SF3, a compressive strength in the range of 30-80 MPa and a ductility represented by fc, ffl, fR1 and fR3 values, wherein the concrete mix contains at least 390 Kg of binder, the concrete mix has a paste volume of 300-600 liters, the concrete mix contains at least two systems of fibers and a general admixture system that is composed of at least 2 sub-admixture systems.

Claims

1. A concrete mix comprising sand, fine aggregates, binder, fibers, and various admixtures, having a consistency from S2 to SF3, a compressive strength in the range of 30-80 MPa and a ductility represented by the following values: 30<fc<80 MPa 3<ffl<12 MPa 3<fR1<12 MPa 2.5<fR3<15 MPa wherein the concrete mix contains at least 390 Kg of binder, the concrete mix comprises a paste volume of 300-600 liters, the concrete mix contains at least two systems of metallic fibers A1 and A2, the fibers system A1 consists of metallic fibers with a dosage of 25-100 kg/m3 with respect to the concrete mix and have an ultimate resistance of at least 1200 MPa, the fibers system A2 consists of low carbon steel fibers with a wavy shape having carbon content of 0.02-0.15% weight and having yield strength of 350-850 MPa and have a dosage of 10 kg-40 kg by m.sup.3 of the concrete mix, the concrete mix contains a general admixture system that is composed of at least 2 sub-admixture systems I and II, wherein the first Admixture system I comprises at least 2 polycarboxylic acid co-polymers (PCE), a strong water reducer PCE and a workability retention PCE, wherein the second Admixture system II is a stabilizer obtained from a compound selected from the group consisting of modified cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, natural starch, modified starch, branched modified starch, naturals gums, Xanthan gum, fine silica, colloidal silica, silica fume and any combination thereof.

2. Concrete mix according to claim 1, wherein the shape of the wavy fibers of fibers system A2 have an amplitude of 0.5-7 mm and a frequency of 0.5 cm.sup.1-6 cm.sup.1.

3. Concrete mix according to claim 1, wherein the wavy fibers have a length of 25-50 mm.

4. Concrete mix according to claim 1, wherein the concrete mix further comprises fibers system B.

5. Concrete mix according to claim 5, wherein fibers system B have a dosage of 0.03 to 0.2% in volume by m3 of the concrete mix.

6. Concrete mix according to claim 1, further comprising coarse aggregates.

7. Concrete mix according to claim 1, wherein the dosing of the Admixture system I is of 0.5-5% weight percent with respect to the binder content and the dosing of the admixture system II is of 0.1-2% weight percent with respect to the binder.

8. Concrete mix according to claim 1, wherein the dosing of the Admixture system I is of 0.1-1% weight percent with respect to the binder content and the dosing of the admixture system II is of 0.1-0.5% weight percent with respect to the binder.

9. Concrete mix according to claim 1, wherein the concrete mix comprises an admixture system III, wherein the third Admixture system III is obtained from a compound selected from the group consisting of cellulose microfibers, synthetic waxes, natural waxes, superabsorbing polymers, starch crosslinked polymers, acrylate crosslinked polymers, hexylene glycol (2-Methyl-2,4-pentanediol) and any combination thereof and the dosage of the admixture system III is of 0.3-6 weight percent with respect to the binder.

10. Concrete mix according to claim 1, wherein fibers system C, comprising synthetic fibers, is added to the concrete mix.

11. Concrete mix according to claim 10, wherein the dosage of fibers system C is of 0.02% to 2% volume with respect to the concrete.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0141] FIG. 1. Flexural test results showing Crack Mouth Opening (CMOD) versus Strength according to EN 14651. This figure shows the values ffl, fR1 and fR3.

[0142] FIG. 2, Schematic drawing of the wavy fibers in fibers system A2 showing the amplitude A and frequency F of the wavy shape.

EXAMPLES OF THE INVENTION

[0143] Various examples of mix designs and corresponding results are presented here according to the invention

[0144] It is clear that the invention is not limited to the provided examples and that the selection of the various ingredients depend on the final application, placing and mechanical targeted properties and cost of the mix design.

Example 1

[0145]

TABLE-US-00008 Material Unit Quantity Total binder content kg/m3 410 CEM I 52.5 N kg/m3 410 w/b eff 0.43 Admix System I % total binder 1.40% content Admix System II % total binder 0.50% content Sand 0/4 round kg/m3 707 Gravel 4/8 crushed kg/m3 443 Gravel 8/11 crushed kg/m3 621 Fiber type A1 - l/d = 80-l = 60 mm, YS = % volume 0.50% 2400, US = 2890 MPa, hooked Fiber type A2 - l/d eq. = 50-l = 38 mm, % volume 0.25% YS = 800 MPa, US = 870 MPa, Wavy shape, A = 3 mm, F = 2 cm1 Entrained air l/m3 15 Paste volume l/m3 321.46 Slump class SF1 Slump mm 670 Workability retention min 90 fc MPa 40 ffl MPa 5.1 fr1 MPa 4.7 fr3 MPa 5.2 E modulus Gpa 31.8

[0146] Example 1 shows a concrete mix design with medium compressive strength and low paste volume according to the invention, with fibers systems A1 and A2, as well as admixture systems I and II.

Example 2

[0147]

TABLE-US-00009 Material Unit Quantity Total binder content kg/m3 750 CEM II/A-LL 52.5 N kg/m3 500 Fly ash kg/m3 200 Silica fume kg/m3 50 w/b eff 0.32 Admix System I % total binder 2.70% content Admix System II % total binder 0.30% content Admix System III % total binder 6.20% content Sand 0/4 crushed kg/m3 646 Gravel 4/8 round kg/m3 453 Gravel 8/10 round kg/m3 194 Fiber type A1 - l/d = 80-l = 60 mm, YS = % volume 0.75% 2400, US = 2890 MPa, hooked Fiber type A2 - l/d eq. == 50, l = 38 mm, % volume 0.30% YS = 800 MPa, US = 870 MPa, Wavy shape, A = 2.5 mm, F = 4.5 cm1 Entrained air l/m3 26 Paste volume l/m3 530.79 Slump class SF2 Slump mm 740 Workability retention min 120 fc MPa 74 ffl MPa 8.5 fr1 MPa 11.8 fr3 MPa 14.7 E modulus Gpa 41.9

[0148] Example 2 shows a concrete mix design according to the invention with high compressive strength and high paste volume, with fibers systems A1 and A2, as well as admixture systems I and II and III.

Example 3

[0149]

TABLE-US-00010 Material Unit Quantity Total binder content kg/m3 630 CEM III/B 52.5R kg/m3 400 Fly ash kg/m3 80 Silica fume kg/m3 50 w/b eff 0.35 Admix System I % total binder 1.80% content Admix System II % total binder 0.45% content Sand 0/4 round kg/m3 721 Gravel 4/8 Crushed kg/m3 289 Gravel 8/11 crushed kg/m3 434 Fiber type A1 - l/d = 40-l = % volume 0.75% 100 mm, YS = 1850 MPa, US = 1920 MPa, straight Entrained air l/m3 38 Paste volume l/m3 441.54 Slump class S5 Slump mm 240 Workability retention min 105 fc MPa 65 ffl MPa 6.7 fr1 MPa 2.1 fr3 MPa 2.5 E modulus Gpa 37.5

[0150] Example 3 shows a concrete mix design with high compressive strength medium to high paste and high binder content, using fibers system A1 only (without fiber system A2 or fiber system B). The concrete mix design of example 3 is not according to the invention since it does not contain fibers system B and does meet the requirements related to the ductility values to be achieved.

Example 4

[0151]

TABLE-US-00011 Material Unit Quantity Total binder content kg/m3 630 CEM III/B 52.5R kg/m3 400 Fly ash kg/m3 80 Silica fume kg/m3 50 w/b eff 0.35 Admix System I % total binder 1.80% content Admix System II % total binder 0.45% content Sand 0/4 round kg/m3 721 Gravel 4/8 Crushed kg/m3 289 Gravel 8/11 crushed kg/m3 434 Fiber type A2 - l/d eq. == % volume 0.75% 60-l = 35 mm, YS = 650 MPa, US = 870 MPa, Wavy shape, A = 4 mm, F = 0.3 cm1 Entrained air l/m3 38 Paste volume l/m3 441.54 Slump class SF1 Slump mm 610 Workability retention min 95 fc MPa 61 ffl MPa 6.5 fr1 MPa 7.4 fr3 MPa 1.2 E modulus Gpa 64.3

[0152] Example 4 shows a concrete mix design similar to examples 3 yet having only fibers system A2. The concrete mix design of example 4 is not according to the invention since it does not contain fibers system A and does meet the requirements related to the ductility values to be achieved.

Example 5

[0153]

TABLE-US-00012 Material Unit Quantity Total binder content kg/m3 530 CEM I 42.5 N kg/m3 300 Fly ash kg/m3 180 Silica fume kg/m3 50 w/b eff 0.45 Admix System I % total binder 1.70% content Admix System II % total binder 0.50% content Sand 0/3 Round kg/m3 693 Gravel 3/8 round kg/m3 362 Gravel 8/11 round kg/m3 454 Fiber type A1 - l/d = 75-l = % volume 0.35% 55 mm, YS = 3100 MPa, US = 3280 MPa, straight Fiber type A2 - l/d eq. == % volume 0.15% 50-l = 38 mm, YS = 800 MPa, US = 870 MPa, Wavy shape, A = 0-6 mm, F = 5 cm1 Fiber type B - Glass - l/d = % volume 0.05% 80-l = 12 mm, US = 2750 MPa, straight Fiber type B - Steel - l/d = % volume 0.25% 80-l = 30 mm, YS = 2570 MPa, US = 3020 MPa, hooked Entrained air l/m3 31 Paste volume l/m3 462.47 Slump class SF3 Slump mm 810 Workability retention min 90 fc MPa 72 ffl MPa 6.9 fr1 MPa 7.2 fr3 MPa 9.1 E modulus Gpa 40.1

[0154] Example 5 shows a concrete mix design according to the invention with high compressive strength medium to high paste and high binder content, using fibers system A1 and A2 with optional fiber system B (mix of glass and steel fibers) as well as admixture systems I and II.

Example 6

[0155]

TABLE-US-00013 Material Unit Quantity Total binder content kg/m3 515 CEM I 32.5 R kg/m3 150 CEM II I/A 52.5 R kg/m3 160 Fly ash kg/m3 180 Silica fume kg/m3 25 w/b eff 0.5 Admix System I % total binder 1.25% content Admix System II % total binder 0.70% content Sand 0/2 round kg/m3 684 Sand 2/4 round kg/m3 358 Gravel 4/8 round kg/m3 448 Fiber type A1 - l/d = 60-l = % volume 0.35% 40 mm, YS = 2850, US = 3120 MPa, hooked Fiber type A2 - l/d eq. == % volume 0.65% 85-l = 55 mm, YS = 800 MPa, US = 825 MPa, Wavy shape, A = 4 mm, F = 1.65 cm1 Fiber type B - Glass - l/d = % volume 0.15% 57-l = 27 mm, US = 3150 MPa, straight Entrained air l/m3 24 Paste volume l/m3 466.28 Slump class S5 Slump mm 250 Workability retention min 150 fc MPa 58 ffl MPa 4.7 fr1 MPa 6.7 fr3 MPa 9.8 E modulus Gpa 34.5

[0156] Example 6 shows a concrete mix design according to the invention with medium compressive strength, medium paste and medium binder content, using fibers system A1 and A2 with optional fibers system B (100% glass fibers) as well as admixture systems I and II.

Example 7

[0157]

TABLE-US-00014 Material Unit Quantity Total binder content kg/m3 580 CEM I 52.5 R kg/m3 250 Fly ash kg/m3 250 Silica fume kg/m3 80 w/b eff 0.35 Admix System I % total binder 3.00% content Admix System II % total binder 1.74% content Sand 0/4 round kg/m3 928 Gravel 4/8 round kg/m3 620 Fiber type A1 - l/d = 85-l = % volume 0.45% 75 mm, YS = 1880 MPa, US = 2350 MPa, hooked Fiber type A2 - l/d eq. == % volume 0.30% 75-l = 51 mm, YS = 650 MPa , US = 725 MPa, Wavy shape, A = 6 mm, F = 0.5 cm1 Fiber type B - Glass - l/d = 88-l = 16 mm, % volume 0.06% US = 3450 MPa, straight Fiber type B - Steel - l/d = 80-l = 25 mm, % volume 0.10% YS = 2740 MPa, US = 3020 MPa, hooked Fiber type C - Polypropylene - l/d = % volume 0.25% 75-l = 50 mm, YS = 550 MPa, US = 680 MPa, straight Entrained air l/m3 14 Paste volume l/m3 436.90 Slump class SF3 Slump mm 780 Workability retention min 120 fc MPa 79 ffl MPa 11.5 frl MPa 11.8 fr3 MPa 14.7 E modulus Gpa 42.3

[0158] Example 7 shows a concrete mix design according to the invention with medium compressive strength, medium paste and medium binder content, using fibers system A1 and A2 with optional fibers system B (mix of glass and steel fibers) and with optional system C, as well as admixture systems I and II.