Presentation on ENHANCEMENT OF SEISMIC PERFORMANCE OF STRUCTURES USING HyFRC by Needhi Kotoky Under the supervision of Dr. Anjan Dutta and Dr. Sajal K. Deb Department of Civil EngineeringIndian Institute of Technology Guwahati

1. ENHANCEMENT OF SEISMIC PERFORMANCE OF
STRUCTURES USING HyFRC
by
Needhi Kotoky
Under the supervision of
Dr. Anjan Dutta and Dr. Sajal K. Deb
Department of Civil Engineering
Indian Institute of Technology Guwahati 1

2. MOTIVATION
2
 Concrete is the most widely used construction
material
 Improve performance of earthquake resistant
structures are good ductility and higher energy
absorption capacity
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 Brittleness of concrete can be overcome by the
inclusion of randomly distributed fibres

3. USE OF FRC
 Use of fibres in concrete removes weaknesses of
concrete-
 low crack growth resistance
 high shrinkage cracking
 low durability, etc
 The use of two or more types of fibres in suitable
combinations helps to arrest crack from micro to
macro level
 Using mixes incorporating different types of fibre is
therefore advantageous
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4. USE OF HyFRC
4
Commonly used fibers for Hybrid Fibre Reinforced
Concrete (HyFRC) are-
 Steel
 Glass
 Synthetic fibres like- Polypropylene, Polyester
 Carbon fibre
 For the present study, Steel fibre of two sizes and
Polypropylene fibre of two different brands available
in India are used
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5.  Inclusion of steel fibres in the
concrete mix is an effective way of
reducing macro-cracking, whilst
polypropylene fibres are very good
at arresting micro-cracking
 Enhance impact strength and
toughness
 Better fibre proportion is judged
on the basis of toughness
Fibers bridging crack in
a HyFRC tested beam
ADVANTAGE OF HyFRC
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6. Material characterization for HyFRC
 Evaluation of best possible combinations based on
toughness of concrete considering prism
specimens
OBJECTIVE OF THE RESEARCH
6
The research aims to provide an enhanced understanding
on the use of HyFRC on the seismic performance of prism
specimen
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7. Fibres
Aspect
ratio
Tensile strength
(MPa)
Geometry
Steel fibre
(Dramix 65mm and
35mm)
65 1150
Hooked
end
FIBRES USED IN TESTING
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8. Fibres
Aspect
Ratio
Tensile strength
(MPa)
Geometry
Polypropelene fibre I
(Recron 3s)
600 450 Triangular flat
Polypropelene fibre II
(Bajaj Plast)
550 670 Fibrillated
(Mesh)
FIBRES USED IN TESTING
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9. FIBRE PROPORTION
9
Fibre
Mix
Steel
(%)
PP (%)
Type 1
PP (%)
Type 2
PL - - -
A1 0.8 0.15 -
A2 0.8 0.2 -
A3 1 0.15 -
A4 1 0.2 -
A5 1.2 0.15 -
A6 1.2 0.2
B1 0.8 - 0.15
B2 0.8 - 0.2
B3 1 - 0.15
B4 1 - 0.2
B5 1.2 - 0.15
B6 1.2 - 0.2
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10. MIXING PROCEDURE FOR DIFFERENT CONSTITUENTS
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11. COMPRESSIVE STRESS-STRAIN CURVE
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12. TENSILE STRESS- STRAIN CURVE
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13. ASTM C 1018
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14. TOUGHNESS EVALUATION
14
Concerns with ASTM C 1018 and JSCE SF4 for toughness
calculation–
 Locating first crack point on the curve is highly
subjective and as such toughness indices measured by
ASTM C 1018 are highly operator dependent
 JSCE produces toughness parameter that is too broad
and hence unable to distinguish between composite
responses at different crack openings
Technique proposed by Banthia and Trottier-
 Post Crack Strength (PCS) method produces toughness
parameter that do not require the identification of first
crack
 Calculated from post peak energy
 Pre-peak energy is omitted for calculation
 Total energy also not requiredNCCE-2017

15. 15
POST CRACK STRENGTH METHOD (PCS)
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16. TEST SET UP
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 150 x 150 x 700 mm beam specimen is tested under
three point loading according to ASTM C 1018 to
evaluate toughness of the specimen by the PCS
method.
 HyFRC specimen showed better flexural strength
than conventional concrete specimen
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17. VeeBee
Time
(sec)
Maximum load
withstand by
the specimen
(KN)
Modulus of
rupture
(Mpa)
15 29.8 6.2
RESULTS
17
VeeBee
Time
(sec)
Maximum load
withstand by
the specimen
(KN)
Modulus of
rupture
(Mpa)
2 18.4 3.8
Conventional concrete
specimen
HyFRC specimen
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18. LOAD-DEFORMATION CURVE
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 Conventional concrete fails suddenly once the
deflection corresponding to the ultimate flexural
strength is exceeded
 HyFRC continues to sustain considerable load even
when deflection is considerably in excess of the
fracture deflection of the conventional concrete
HyFRCCONVENTIONAL CONCRETE
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19. TOUGHNESS EVALUATION OF THE PRISMS
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Specimen
Type
Average
compressive
strength (MPa)
Maximum load
applied to the
specimen (KN)
Toughness
(MPa)
Modulus of
rupture
(MPa)
PL 34.23 18.27 0.34 3.9
A1 34.96 24.8 2.47 5.8
A2 33.65 27.44 2.67 5.7
A3 35.31 28.16 2.97 6.7
A4 34.22 20.18 2.11 4.9
A5 33.44 25.82 2.54 5.6
A6 34.6 25.07 2.57 5.7
B1 34.04 19.54 1.91 4.8
B2 34.65 17.98 1.87 5.1
B3 33.98 20.73 2.22 5.8
B4 34.17 22.32 2.45 4.3
B5 33.34 23.41 2.53 5.1
B6 34.16 25.1 2.61 5.2

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 Fractures specimen of HyFRC shows that failure takes
place primarily due to fiber pull-out or debonding
 Unlike conventional concrete, HyFRC specimen does
not break immediately after initiation of first crack
 This has the effect of increasing work of fracture
referred as toughness – represented by area under the
load-deflection curve
 Influence of fibres on concrete is reflected by flexural
strength
 Best proportion is found to be 1% steel and 0.15%
polypropelene (Recron 3s) in term of toughness
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CONCLUDING REMARKS

21.  Soleimani, S.S. (2002). Flexural response of hybrid fiber
cementitious composites. Master thesis, The university of British
Columbia
 Banthia, N., Trottier, J.F. (1995). Test methods for flexural
toughness characterization of fiber reinforced concrete: some
concerns and a proposition. ACI Materials Journal, vol. 92, no. 1,
pp. 48-57.
 Bentur, A., & Mindess, S. (2006). Fibre reinforced cementitious
composites. CRC Press.
 American Concrete Institute. (2002).State-of-the-Art Report on
Fiber Reinforced Concrete. ACI 544.1R-96
 Banthia, N., Soleimani, S.M. (2005). Flexural response of hybrid
fiber reinforced cementitious composites, ACI Materials Journal,
vol. 102, no. 5.
 American Society for Testing and Materials. (1989). Standard Test
Method for Flexural Toughness and First-Crack Strength of Fiber
Reinforced Concrete (Using Beam with Third Point Loading). ASTM
Standards for Concrete and Aggregates, vol. 04.02, Standard
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REFERENCES
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22.  Qian, C.X., Stroeven, P. (2000). Development of hybrid
polypropylene-steel fibre-reinforced concrete, Cement and
Concrete Research, vol. 30 , pp. 63–69
 Sivakumar,A., Manu Santhanam,M. (2007). Mechanical properties
of high strength concrete reinforced with metallic and non-
metallic fibres. Cement & Concrete Composites, vol. 29 , pp. 603–
608
 Ganesan,N., Indira,P.V., Sabeena,M.V. (2014). Behaviour of hybrid
fibre reinforced concrete beam–column joints under reverse cyclic
loads. Materials and Design, vol. 54 ,pp. 686–693
 Japan Concrete Institute. (1983). Method of Test for Flexural
Strength and Flexural Toughness of Fiber Reinforced Concrete.
Standard SF4, JCI Standards for Test Methods of Fiber Reinforced
Concrete, pp. 45-51.
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REFERENCES
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