Presentation for National Engineering Day 2013

1. Performance of Steel Fiber
Reinforced Concrete under High
Temperature and Impact Load from
Direct Fire Weapon
Assc. Prof. Dr. Piti Sukontasukkul
King Mongkut University of Technology-North Bangkok
Thailand Concrete Association

2. Presentation Topic
Performance of SFRC subjected to high
temperature
• Concrete under high temperature
• SFRC under high temperature
• Steel fiber vs. Other fibers
Performance of SFRC under impact loading
• Structure under attack
• Material behavior under impact loading
• Performance of SFRC under impact loading

3. Performance of SFRC under
High Temperature

4. General Knowledge
To Stop Fire
Credit http://en.wikipedia.org/wiki/Fire
• Turning off the gas supply, which removes
the fuel source;
• Covering the flame completely, which
remove the oxygen in the air and
displaces it CO2;
• Application of water, which removes heat
from the fire faster than the fire can
produce it
• Application of a retardant chemical such
as Halon to the flame, which retards the
chemical reaction itself until the rate of
combustion is too slow to maintain the
chain reaction.

5. Temperature
by Flame
Appearance
Temperatures of flames by
appearance
Red
Orange
White
Just visible: 525
°C (980 °F)
Deep: 1,100 °C
(2,000 °F)
Whitish: 1,300 °C
(2,400 °F)
Dull: 700 °C
(1,300 °F)
Clear: 1,200 °C
(2,200 °F)
Bright: 1,400 °C
(2,600 °F)
Cherry, dull: 800
°C (1,500 °F)
Cherry, full: 900
°C (1,700 °F)
Credit http://en.wikipedia.org/wiki/Fire
Cherry, clear:
1,000 °C
(1,800 °F)
Dazzling: 1,500
°C (2,700 °F)

6. Behavior of Concrete Subjected
to High Temperature
Pore pressure rises
Increasing compression stress
at the heated surfaces
Internal cracking between agg.
and paste
Cracking and spalling between
paste and rebar.
Strength drop ?????

7. Expansion under Thermal Difference
Expansion of RC. Structure
under High Temp. include
Expansion of aggregates
Expansion of cement
paste
Expansion of rebar
Thermal Expansion
Coefficient
Cement paste
11-16 x 10-6 /oC
Coarse aggregate
0.9-12 x 10-6/oC
Steel
11-12 x 10-6 /oC

8. Temperature Change vs. Strain

9. Type of Thermal Cracking and Spalling
Violent Spalling,
Progressive Gradual Spalling,
• Appear at the very beginning of the
exposure.
• A separation of small pieces from the
cross section, during energy release.
They form popping off pieces with a
certain speed, and a cracking sound.
• After long period of exposure, loss of
strength due to internal crack and
deterioration of cement paste cause
this kind of spalling.
Corner Spalling
Explosive Spalling,
• The type of spalling that occurs when
a corner of concrete breaks off due to
the restrained expansion or the
difference in TEC of paste and rebar.
• This occurs when there is a thermal
gradients in the cross-section (one
side of structure expose to high
temperature while the other side does
not).

10. http://www.promat-tunnel.com/en/concretespalling-effect-standard-fire-tests.aspx

11. Plain Concrete vs. SFRC subjected to Fire
Plain Concrete
SFRC
• Unequal expansions of cement
paste and aggregates cause
cracking and spalling to occur.
• At temperature lower 200oC, the
expansions are still small, in many
cases the strength is found to
remain unchanged or may be
increased slightly.
• At temperature higher than
200oC, the strength begins to
drop.
• The cracks are restrained by
fibers, this reduce the process of
disintegration and maintain the
ability of concrete to sustain load.
• Similar results are found at
temperature lower than 200oC,
increasing in strength and
toughness is found.
• At temperature higher than
200oC, both strength and
toughness are found to decrease
but still higher than plain concrete

12. Compressive Strength
Mahasneh, B, The Effect of Addition of Fiber
Reinforcement on
Fire Resistant Composite Concrete Material, J.
Applied Sci., 5 (2): 373-379, 2005

13. Tensile Strength
Mahasneh, B, The Effect of Addition of Fiber
Reinforcement on
Fire Resistant Composite Concrete Material, J.
Applied Sci., 5 (2): 373-379, 2005

14. EXPERIMENTS AT KMUTNB:FLEXURAL PERFORMANCE OF FRC
SUBJECTED TO FIRE

15. Flexural Toughness ASTM C1018
Flexural Toughness
FIRST
CRACK
•  = Area under the curve up to elastic
limit (OAB)
10.5δ
5.5δ
3δ
δ
0 0'
• 10.5 = Area under the curve up to 10.5
times of  (OAGH)
=
Area OACD / Area OAB
• I10
=
Area OAEF / Area OAB
• I20
=
Area OAGH / Area OAB
B
D
F
H
DEFLECTION
FIRST
CRACK
A
C
E
G
LOAD
• I5
E
G
• 5.5 = Area under the curve up to 5.5
times of  (OAEF)
Toughness Indexes
C
LOAD
• 3 = Area under the curve up to 3 time of
 (OACD)
A
10.5δ
5.5δ
3δ
δ
0 0'
B
DEFLECTION
D
F
H

16. Standard Fire Test ASTM E119-98
Sukontasukkul, P., and Pomchiengpin, W., Post-Crack (or Post
Peak) Flexural Reponse and Toughness of FRC after Exposure to
Elavated Temperature, Journal of Construction and Building
Material (JCBM), Vol. 24, 2010, pp. 1967-1974.

17. Flexural Response of PC vs. SFRC
30
0.5%SFRC
30
25
Load (kN)
Plain Concrete
25
Load (kN)
20
Room Temp
15
15
5
600oC
5
600oC
10
400oC
10
400oC
20
800oC
0
800oC
0
2
0
0
0.2
0.4
0.6
Deflection (mm)
0.8
Room Temp
4
Deflection (mm)
6
8
1
30
400oC
1.0%SFRC
25
SFRC
(@Bekeart HE Steel Fiber)
Load (kN)
Plain Concrete
600oC
20
15
Room Temp
10
800oC
5
Sukontasukkul, P., and Pomchiengpin, W., Post-Crack (or Post
Peak) Flexural Reponse and Toughness of FRC after Exposure to
Elavated Temperature, Journal of Construction and Building
Material (JCBM), Vol. 24, 2010, pp. 1967-1974.
0
0
2
4
Deflection (mm)
6
8

18. Toughness Indexes of SFRC
SFRC
25.0
20.0
15.0
Before subjecting to Fire
10.0
5.0
0.5%
1.0%
Room Temp
0.5%
1.0%
0.5%
400 C
I5
1.0%
600 C
I10
0.5%
1.0%
800 C
I20
Sukontasukkul, P., and Pomchiengpin, W., Post-Crack (or Post
Peak) Flexural Reponse and Toughness of FRC after Exposure to
Elavated Temperature, Journal of Construction and Building
Material (JCBM), Vol. 24, 2010, pp. 1967-1974.
After subjecting to Fire (800oC)

19. Steel Fiber vs. Synthetic Fibers
30
30
0.5%PE/PP FRC
0.5%PPFRC
25
25
20
400oC
Room Temp
15
10
Load (kN)
Load (kN)
20
600oC
15
600oC
10
800oC
5
400oC
5
800oC
0
0
2
4
Deflection (mm)
6
8
0
PP/PE Fiber (@Strux Fiber)
2
4
Deflection (mm)
6
8
PPRC (@Bekeart PP Fiber)
30
30
1.0%PE/PP FRC
1.0%PPFRC
25
25
400oC
400oC
20
15
Load (kN)
20
Load (kN)
Room Temp
0
600oC
600oC
15
10
10
5
5
800oC
Room Temp
0
800oC
Room Temp
0
0
2
4
Deflection (mm)
6
8
0
2
4
Deflection (mm)
6
8

20. Flexural Toughness Synthetic Fibers
PEFRC
PPFRC
25.0
30.0
20.0
25.0
20.0
15.0
15.0
10.0
10.0
5.0
5.0
-
0.5%
1.0%
Room Temp
0.5%
1.0%
0.5%
400 C
I5
1.0%
0.5%
600 C
I10
I20
Sukontasukkul, P., and Pomchiengpin, W., Post-Crack (or Post
Peak) Flexural Reponse and Toughness of FRC after Exposure to
Elavated Temperature, Journal of Construction and Building
Material (JCBM), Vol. 24, 2010, pp. 1967-1974.
1.0%
800 C
0.5%
1.0%
Room Temp
0.5%
1.0%
0.5%
400 C
I5
1.0%
600 C
I10
I20
0.5%
1.0%
800 C

21. Cross-section after 800oC
Synthetic FRC
Steel FRC
Sukontasukkul, P., and Pomchiengpin, W., Post-Crack (or Post Peak) Flexural Reponse and Toughness of FRC after Exposure to Elavated Temperature,
Journal of Construction and Building Material (JCBM), Vol. 24, 2010, pp. 1967-1974.

22. Ultrasound Test
Pulse Velocity (m/s)
5,000
4,500
4,000
3,500
3,000
2,500
Plain
PEFRC-0.5
PEFRC-1.0
PPFRC-0.5
PPFRC-1.0
SFRC-0.5
SFRC-1.0
Room
400 C
600 C
800 C
4,795
4,683
4,718
4,667
4,728
4,683
4,667
4,445
4,383
4,295
4,357
4,122
4,525
4,277
4,132
4,260
3,590
3,702
3,620
3,815
3,687
3,257
2,922
2,866
2,883
2,808
2,990
2,972
Sukontasukkul, P., and Pomchiengpin, W., Post-Crack (or Post Peak) Flexural Reponse and Toughness of FRC after Exposure to Elavated Temperature,
Journal of Construction and Building Material (JCBM), Vol. 24, 2010, pp. 1967-1974.

23. Conclusion
Steel fibers exhibit the ability to improve the fire
resistance of concrete as seen by the ability the
maintain strength and toughness after subjection to
high elevated temperature.
Steel fiber’s ability to bridge across the cracks that
occurred during exposure to fire play an important
role on this matter.

25. Concrete Under High Rate of Loading
Concrete may sometime be
required to withstand dynamic
loads due to impact, or explosion.
Under high rate of loading, the
strength of concrete increases with
the increasing loading rate.
90
Static loading
Impact loading (250mm)
Impact loading (500mm)
80
70
Large cracks are typically found.
Stress (MPa)
Cracks are forced to propagate
through aggregates.
60
50
40
30
20
10
-
0.005
0.010
0.015
Strain
0.020
0.025
0.030

26. SFRC under Impact Loading
Mechanical Properties: strength
increases, toughness increases and
bond strength increases
Multiple cracks with less severity
are often found.
90
Static loading
Impact loading (250mm)
Impact loading (500mm)
80
70
60
Stress (MPa)
Under high rate of loading, fibers
are forced to pullout at faster rate,
thus cause the increase in
mechanical properties.
50
40
30
20
10
-
0.005
0.010
0.015
Strain
0.020
0.025
0.030

27. Structures Being Hit by Bullets
Three Scenarios
• Penetrated Bullets: When the bullets
hit the wall and penetrate through.
They injure people or damage
properties
• Un-penetrated Bullets: when the
bullets hit the wall, but do not
penetrate, instead turning into flying
debris (broken concrete pieces and
ricocheted bullets). The debris injure
people and damage properties.
• Panicking: People get panic, running
around, stumbling and get hurt.

28. Typical Failure Patterns of Bulletproof Panel
Global
Local
Penetration
Perforation
Flexure
Scabbing
Spalling
In the case of impact
loading by bullet which
leading to penetration,
the specimen response
is usually dominated
by the local response
of the small zone at
the contact area

29. Main Ideas of Bulletproof Panel
Requirement for bulletproof
panel:
• Penetration or perforation must not
occurs.
In order to achieve that:
• Improve impact resistance by
increasing strength and energy
absorption ability of the panel.
• Anticipating energy dissipation by
using soft medium into the panel.
http://www.examiner.com/article/ethicspanel-ruling-keeps-jobsohio-bullet-proofon-kasich-board-biz-deals

31. Two Types of Panel
SFRC Panel
Rubberized Concrete
Steel Fiber Reinforced Concrete
• Fiber: Hooked End steel fiber (©Dramix Bekeart), Addition
rate: 2%-4%
• Thickness: 3 cm.
• Category: Improve impact resistance using steel fiber.
Double layer: SFRC and Rubberized Concrete
• Fiber: Hooked End steel fiber (©Dramix Bekeart) , Addition
rate: 2%-4%
• Crumb rubber: Commercial type, Size: passing seive No. 6.
• Panel Thickness: 3 cm. Varied Thickness between layer from
0.5:2.5, 1.0:2.0 and 1.5:1.5
• Category:
• Adding energy dissipation medium (rubberized concrete),
• Increase impact resistance using steel fiber
T1
T2

32. Two Types of Bullet
Manufacturer
Winchester
Load
FMJ
Mass
Velocity
7.5 g (115 gr) 352 m/s
Energy
462 J
Remington
FMJ
15 g (230 gr) 255 m/s
483 J
Expansion Penetration
9.1 mm
620 mm
11 mm
690 mm
PC
41 mL
TSC
174 mL
70.3 mL
150 mL

33. Failure Patterns PC vs. SFRC Panel
Plain concrete Panel
29
Front
43
.
Back
SFRC Panel
.

34. Failure Patterns : Double Layer Panel
Typical Failure Patterns
Partially Energy Dissipation
Ideal Failure Patterns
Full Energy Dissipation

35. Passing Requirement
Type
R25
R50
R75
S2
S3
S4
R50/S2
R75/S2
R100/S2
R50/S3
R75/S3
R100/S3
R50/S4
R75/S4
R100/S4
A-R75/S2
B-R75/S2
A-R75/S3
B-R75/S3
9 mm
Failure Type
Perforation
Perforation
Perforation
Scabbing
Scabbing
Scabbing
Scabbing
Scabbing + Spalling
Scabbing + Spalling
Scabbing
Scabbing
Scabbing + Spalling
Scabbing + Spalling
Scabbing
Scabbing
Scabbing + Spalling
Scabbing + Spalling
Scabbing + Perforation
Scabbing + Perforation
11 mm
Classification
Failure Type
not pass
Perforation
not pass
Perforation
not pass
Perforation
pass
Scabbing
pass
Scabbing
pass
Scabbing
pass
Scabbing
pass
Scabbing + Spalling
pass
Scabbing + Spalling
pass
Scabbing
pass
Scabbing
pass
Scabbing
pass
Scabbing
pass
Scabbing
pass
Scabbing
pass
Scabbing + Perforation
pass
Scabbing + Perforation
not pass
Scabbing + Perforation
not pass
Scabbing + Perforation
Classification
not pass
not pass
not pass
pass
pass
pass
pass
pass
pass
pass
pass
pass
pass
pass
pass
not pass
not pass
not pass
not pass

36. Typical Acceleration Res.
SFRC (9 mm)

37. Typical Acceleration Res.
Double Layer (9 mm Bul.)

38. Comparison
Single Layer Plate
Double Layer Plate
Responding
time: Slower in
Double layer
plate
Acceleration
Value: Lower in
Double layer
plate

39. Center Acc. vs. Rubber content
Double-layer plate
1,200.00
0% Crumb Rubber
50% CR (0.5/2.5)
75%CR (0.5/2.5)
100%CR (0.5/2.5)
1,053.38
1,000.00
Acceleration (m2/s)
864.41
819.33
800.00
735.98
785.21
759.05
602.97
600.00
432.51
400.00
579.81
526.22
389.40
353.43
200.00
SFRC2%
SFRC3%
SFRC4%

40. 200.00
100.00
-
432.51
355.28
300.00
100R4S
(0.5/2.5)
735.98
648.22
546.52
353.43
100R3S
(0.5/2.5)
100R2S
(0.5/2.5)
602.97
506.47
389.40
452.31
400.00
75R4S
(0.5/2.5)
75R3S
(0.5/2.5)
738.45
864.41
759.05
1,000.00
75R2S
(0.5/2.5)
526.22
451.34
500.00
50R4S
(0.5/2.5)
554.84
600.00
50R3S
(0.5/2.5)
700.00
628.42
800.00
819.33
900.00
50R2S
(0.5/2.5)
Acceleration (m2/s)
Bullet Type vs. Center Acceleration
9 mm.
11 mm.

41. Displacement (9 mm.)
SFRC 2%
50RS2
SFRC 3%
50RS3

42. Conclusions
Steel fiber reinforced concrete exhibit superior impact resistance as seen by
the test results that no perforation occur in the SFRC panels.
Crumb rubber used in this study has shown it ability to enhance the
efficiency of the bulletproof SFRC panels.
The results are successfully shown that the rubberized concrete layer is able
to act as a cushion layer and dissipate the impact energy from the bullet test
as seen by the decreasing values of acceleration, displacement and D/W
ratios.