Comparative Graphical Analysis of Material Properties of various FRP Rebars

The following data have been obtained from ACI 440.1R-06 Chapter 3.

Steel GFRP CFRP AFRP

Density , lb/ft3

(g/cm3)

493.00

(7.90)

77.8 to 131.00

(1.25 to 2.10)

93.3 to 100.00

(1.50 to 1.60)

77.80 to 88.10

(1.25 to 1.40)

Nominal Yield

Stress, ksi (MPa)

40 to 75

(276 to 517)

N/A N/A N/A

Tensile Strength,

ksi (MPa)

70 to 100

(483 to 690)

70 to 230

(483 to 1600)

87 to 535

(600 to 3690)

250 to 368

(1720 to 2540)

Elastic Modulus x

103 ksi, (GPa)

29.0

(200.0)

5.1 to 7.4

(35.0 to 51.0)

15.9 to 84.0

(120.0 to 580.0)

6.0 to 18.2

(41.0 to 125.0)

Yield Strain % 0.14 to 0.25 N/A N/A N/A

Rupture Strain

%

6.0 to 12.0 1.2 to 3.1 0.5 to 1.7 1.9 to 4.4

Note :

Almst zero yield stress and strain indicate the brittle nature of the fiber reinforced polymer bars.

Where as steel ‘s yield stress ranges from 40 to 75 ksi.

Graphical represantions of the data are shown below in :

1.25 1.5 1.25

7.9

2.1 1.6 1.4

0

2

4

6

8

10

Steel GFRP CFRP AFRP

Typical densities of Reinforcing Bars in g/cm3

Note :

High elastic modulus of CFRP indicates its high stiffness compared to GFRP and AFRP.

GFRP has low stiffness than steel rebars.

Note :

Very high strength compared to steel.

CFRP and AFRP has almost 5 times the tensile strength of steel, GFRP is almost double that of

steel.

200

35

120

41

51

580

125

0

100

200

300

400

500

600

700

800

Steel GFRP CFRP AFRP

Elastic Modulus in Gpa

483 489 600

1720 690

1600

3690 2540

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Steel GFRP CFRP AFRP

Tensile Strength in MPa

Note :

Very less strain values than steel, indicates the brittle nature.

Glass has very good impact resistance due to their high strain to failure, when compared to

other fibers.

Aramid also has excellent impact resistance, particularly to ballistic impact.

Steel has highest strain failure, sometimes as high as 20%.

COST COMPARISON

Source : FRPRCS-8 University of Patras, Patras, Greece, July 16-18, 2007 WHY IS FRP NOT A FINANCIAL SUCCESS? Chris BURGOYNE Ioannis BALAFAS

6

1.2 0.5 1.9

12

3.1

1.7

4.4

0

2

4

6

8

10

12

14

16

18

20

Steel GFRP CFRP AFRP

Rupture Strain in %

To summarize:

Table 1 Qualitative comparison between E-glass, HT-carbon and Aramid fibers.

Criterion Fiber Composite bars made of:

Glass fiber Carbon fibers Aramid fiber

Tensile strength Very good Very good Very good

Compressive strength Good Very good Inadequate

Young’s modulus Adequate Very good Good

Long-term behavior Adequate Very good Good

Fatigue behavior Adequate Excellent Good

Bulk density Adequate Good Excellent

Alkaline resistance Inadequate Very good Good

Price Very good Adequate Adequate

0

2

4

6

8

10

12

14

Prestressedsteel

ReinforcingSteel

GFRP CFRP AFRP

1

3

6.5

12.5 12.5

Cost ratio of FRP rebars to Prestressed Steel