1. Fibers
EB001 –Design and Control of Concrete Mixtures—14th Edition, 2002, Chapter 7, pages 121 to 128

2. Types of Fibers Steel Glass Synthetic Natural
Fig Steel, glass, synthetic and natural fibers with different lengths and shapes can be used in concrete. (69965)

3. Effects of Different Fibers on Concrete Properties
Type of Fiber
Reduced plastic shrinkage cracking
Synthetic,
Steel
Increased tensile strength
Glass,
Steel,
Carbon
Increased flexural strength
Glass

4. Steel Fibers
Fig Steel fibers with hooked ends are collated into bundles to facilitate handling and mixing. During mixing the bundles separate into individual fibers. (69992)
Fig Bridge deck with steel fibers. (70007)

5. Properties of Steel Fibers
Relative density
Diameter, µm (0.001 in.)
Tensile strength, MPa (ksi)
Modulus of elasticity, MPa (ksi)
Strain at failure, %
7.80
210,000
(4-40)
(70-380)
(30,000)
Table 7-1. Properties of Selected Fiber Types. Adapted from PCA (1991) and ACI 544.1R-96.

6. Application and Fabrication Methods of Steel Fibers
Conventionally mixed—used for
Overlays
Shotcrete
Stabilization of rockslopes
Tunnel linings
Coal mine shaft linings
Slurry Infiltrated Fiber Concrete
Fig Shotcrete. (70018)

7. Slurry-Infiltrated Concrete (SIFCON)
Cement
1000 kg/m3 (1686 lb/yd3)
Water
330 kg/m3 (556 lb/yd3)
Siliceous Sand  0.7 mm
860 kg/m3 (1450 lb/yd3)
Silica Slurry
13 kg/m3 (1.3 lb/yd3)
High-Range Water Reducer
35 kg/m3 (3.7 lb/yd3)
Steel Fibers (about 10 Vol.-%)
800 kg/m3 (84 lb/yd3)
Fig Tightly bunched steel fibers are placed in a form, before cement slurry is poured into this application of slurry-infiltrated steel-fiber concrete (SIFCON). (60672)
Table 7-2. SIFCON Mix Design.

8. Glass Fibers
Fig (top) Glass-fiber-reinforced concrete panels are light and strong enough to reduce this building’s structural requirements. (bottom) Spray-up fabrication made it easy to create their contoured profiles. (60671, 46228)

9. Properties of Glass Fibers
Glass fiber type
Relative density
Diameter, µm (0.001 in.)
Tensile strength, MPa (ksi)
Modulus of elasticity, MPa (ksi)
Strain at failure, % E
2.54
8-15
72,000
( )
( )
(10,400) AR
2.70
12-20
80,000
( )
( )
(11,600)
Table 7-1. Properties of Selected Fiber Types. Adapted from PCA (1991) and ACI 544.1R-96.

10. Synthetic Fibers Acrylic Aramid Carbon Nylon Polyester
Polypropylene (Photo)
Fig Polypropylene fibers are produced either as (left) fine fibrils with rectangular cross section or (right) cylindrical monofilament. (69993)

11. Properties of Synthetic Fibers
Synthetic fiber type
Relative density
Diameter, µm
Tensile strength, MPa
Modulus of elasticity, MPa
Strain at failure, %
Acrylic
1.18
5-17
17,000-19,000
28-50
Aramid
1.44
10-12
62, ,000
2-3.5
Carbon
1.90
8-0
230, ,000
Nylon
1.14 23
1000
5,200 20
Polyester
1.38
10-80
10,000-18,000
10-50
Poly-ethylene
0.96
80-600
5,000
12-100
Poly-propylene
0.90
20-200
3,500-5,200
6-15
Table 7-1. Properties of Selected Fiber Types. Adapted from PCA (1991) and ACI 544.1R-96.
Metric

12. Properties of Synthetic Fibers
Synthetic fiber type
Relative density
Diameter, in.
Tensile strength, ksi
Modulus of elasticity, ksi
Strain at failure, %
Acrylic
1.18
30-145
2,500-2,800
28-50
Aramid
1.44
9,000-17,000
2-3.5
Carbon
1.90
33,400-55,100
Nylon
1.14
0.9
140
750 20
Polyester
1.38
40-170
1,500-2,500
10-50
Poly-
ethylene
0.96
1-40
11-85
725
12-100
propylene
0.90
0.8-8
65-100
6-15
Table 7-1. Properties of Selected Fiber Types. Adapted from PCA (1991) and ACI 544.1R-96.
Inch-Pound

13. Properties of Natural Fibers
Natural fiber type
Relative density
Diameter, µm (0.001 in.)
Tensile strength, MPa (ksi)
Modulus of elasticity, MPa (ksi)
Strain at failure, %
Wood cellulose
1.50
(1-5)
(51-290)
10,000-40,000 (1,500-5,800)
Sisal
(40-85)
13,000-25,000 (1,900-3,800)
3.5
Coconut
(4-16)
(17-29)
19,000-25,000 (2,800-3,800)
10-25
Bamboo
(2-16)
(51-73)
33,000-40,000 (4,800-5,800)
Jute
(4-8)
(36-51)
25,000-32,000 (3,800-4,600)
Elephant grass
425
180 (17)
4,900 (26)
4, (710)
3.6
Table 7-1. Properties of Selected Fiber Types. Adapted from PCA (1991) and ACI 544.1R-96.