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Transcript of INVESTIGATION ON BEHAVIOUR OF HIGH ... II/IJAET VOL II...International Journal of Advanced...
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
IJAET/Vol.II/ Issue I/January-March 2011/190-202
Research Article
INVESTIGATION ON BEHAVIOUR OF HIGH
PERFORMANCE REINFORCED CONCRETE COLUMNS
WITH METAKAOLIN AND FLY ASH AS ADMIXTURE P.Muthupriya*, Dr.K.Subramanian**, Dr.B.G.Vishnuram***
Address for Correspondence
*Senior Lecturer, Department of Civil Engineering, VLB Janakiammal College Of Engineering And
Technology, Coimbatore-641 042.
** Professor & Head, Department of Civil Engineering, Coimbatore Institute Of Technology,
Coimbatore-641 014.
***Principal, Easa College of Engineering and Technology, Coimbatore-641105.
E Mail [email protected], [email protected],[email protected]
ABSTRACT
An experimental investigation was carried out to study the behaviour of High Performance Reinforced Concrete
column (HPRC) to assess the suitability of HPRC columns for the structural applications. High Performance
Concrete used (HPC) in this study was produced by partial replacement of Ordinary Portland Cement (OPC)
with metakaolin and Fly ash. As many as six mixes of HPC were considered with three mixes viz. M2,M3 M4
for the replacement of cement with metakaolin by mass equal to 5%,7.5% and 10%. Whereas for other three
mixes such as M5,M6,M7 the replacement for OPC was done by metakaolin and flyash keeping a constant value
of 10% fly ash in addition to 5%,7.5% and 10% of metakaolin respectively. Besides the concrete mix M1 made
of normal concrete was also adopted for comparison purpose. Seven each for long and short columns were cast
and tested in the structural engineering laboratory in the loading frame of 1000kN capacity. The size of short
columns was 100x100x1000mm and for these long columns the size adopted was 100x100x1500mm. Short
columns were tested under concentric axial load and the long columns were tested under compression and
uniaxial bending with minimum eccentricity. The failure of short columns were prematured and showed high
brittleness whereas in the case of long columns there were good buckling effect but the failure concentrated
either at column head portion or at the base due to spalling of concrete accompanied with heavy cracks. The
performance of short columns was studied by evaluation of ductility index and stiffness whereas for long
columns ductility was obtained from load versus deflection curves and moment curvature curves. It was
observed that the behaviour of HPRC columns was marginally better than those of normal concrete. Of course,
from the literature survey it was learnt that high performance reinforced concrete columns require closer spacing
of lateral ties or else confinement externally for enhanced performance. Besides the companion specimens such
as cubes, cylinders and prism beams were also cast and tested to study the strength characteristics such as
compressive strength, split tensile strength and flexural strength of HPC mixes adopted in this study. There is a
good increase for all the above mentioned strength for HPC mixes adopted in this study.
KEYWORDS: HPC, fly ash, Metakaolin, High performance reinforced concrete columns, ductility index and
ductility parameter
INTRODUCTION
General
Cement concrete is the most extensively used
construction material. Maintenance and repair
of concrete structures is a growing problem
involving significant expenditure. As a result
carried out world wide, it has been made
possible to process the material to satisfy more
stringent performance requirements, especially
long – term durability. High performance is
generally assumed to be synonymous with
high strength, although this is not true in every
case. Unacceptable rates of deterioration due
to environmental effects indicate that only
compliance with strength requirements,
although need, is not adequate to ensure long –
term, durability, which is the primary
requirement for high performance. It is
generally accepted, that the high performance
of the very concrete contributes to low
permeability, stronger and denser transition
zone between aggregate and cement paste in
the concrete. This also adds to the abrasion
resistance of concrete. According to ACI “
High Performance Concrete is defined as
concrete which meets special performance and
uniformity requirements that cannot always be
achieved routinely by using conventional
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
IJAET/Vol.II/ Issue I/January-March 2011/190-202
materials and normal mixing, placing and
curing practices.
MATERIALS USED
• Ordinary Portland Cement (OPC) 53 grade
conforming to IS 8112.
• Locally available river sand was used as fine
aggregate.
• Crushed granite coarse aggregate of size
12.5mm was used.
• Potable water was used for mixing and
curing purpose.
• Metakaoline and flyash are used as mineral
admixtures.
• A commercially available sulphonated
naphthalene formaldehyde based
superplasticizer (CONPLAST SP 430) was
used as chemical admixture to enhance the
workability of the concrete.
EXPERIMENTAL PROGRAMME
The mixes M1, M2, M3 and M4 were obtained
by replacing 0, 5, 7.5 and 10 percent of the
mass of cement by metakaoline.
The mix M5, M6 and M7 were obtained by
replacing the mass of cement by metakaoline
and flyash. The water binder ratio (w/b) of
0.32 for all mixes was maintained. Chemical
admixture used for the project is sulphonated
naphthalene type super plasticizer Conplast
SP430.All the test specimens such as cubes,
cylinders and prisms were cast using steel
moulds. Machine oil was applied in the mould
before casting of HPC specimens. The
constituents of concrete are thoroughly mixed,
placed and well compacted. The specimens
were removed from the mould after 24 hours
and cured in water. The cube specimen were
used for compressive strength test and
durability study. The cylinder specimens were
used to study split tensile strength test and
prisms were used to determine flexural
strength.
The compressive strength test is conducted in
the Compression Testing Machine of 2000 kN
capacity, the test results are listed in Table 5.
Table I Properties of 53 Grade OPC
Test particulars Result obtained Requirements as per IS:8112-
1989
Specific gravity 3.15 3.10-3.15
Normal consistency (%) 31 30-35
Initial setting time (minutes) 37 30 minimum
Final setting time (minutes) 570 600 maximum
Compressive strength (MPa)
a) 3 days
b) 7 days c) 28 days
34
45
64
33
43
53
Table II Properties of Aggregates
Result obtained Result obtained Test particulars
Fine Aggregate Coarse Aggregate
Specific gravity 2.67 2.65
Fineness modulus 2.25 5.96
size Passing through
4.75mm sieve
Passing through 20mm sieve and retained in
10mm sieve
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
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Table III Properties Of Metakoalin
S.No Property Value
1. Average particle size um
2. Residue 325 mesh 0.5 (% max)
3. Surface Area 15 m2/kg
4. Pozzolan Reactivity 1056 Ca(OH)2/gm
5. Specific gravity 2.5
6. Bulk density 300+ 30 (gm/1 lit)
7. Brightness 80 + 2
8. Physical foam off – White powder
Table IV Mix Proportion Details
Mix Cement
(kg/m3)
M
(kg/m3)
F
(kg/m3)
Fine
Aggregate
(kg/m3)
Coarse
Aggregate
(kg/m3)
SP
(Lit/m3)
w/b
M1 500 0 0 716.916 1046.76 4.16 0.32
M2 476.190 23.8 0 716.916 1046.76 6.25 0.32
M3 465.116 34.88 0 716.916 1046.76 7.30 0.32
M4 454.54 45.45 0 716.916 1046.76 8.40 0.32
M5 434.78 21.74 43.478 716.916 1046.76 10.42 0.32
M6 425.53 31.915 42.553 716.916 1046.76 10.42 0.32
M7 416.67 41.67 41.67 716.916 1046.76 10.42 0.32
Table V Compressive Strength Results
3Days 7Days 28Days 56Days 90 Days Mix % of
HRM
% of
Flyash (MPa) (MPa) (MPa) (MPa)
M1 0 0 41 50 60.5 65 77
M2 5 0 42.4 55.35 63.7 70 81.5
M3 7.5 0 46 57.5 67 72.95 84
M4 10 0 44.5 56.63 65.2 69 80
M5 5 10 43 54.5 66 70.42 82
M6 7.5 10 47.5 58.1 68.5 74 86.4
M7 10 10 46.2 54.05 64.8 71.5 84.5
DISCUSSIONS
The compressive strength for various mixes
M1 to M7 at the age of 3, 7, 28, 56 and 90
days are obtained from the test results. When
metakaolin is added as additional admixture,
there is a significant improvement in the
strength of concrete because of high
pozzolanic action to form more calcium
silicate hydrate (CSH) gel. The maximum
compressive strength obtained for Mix M6
(contains 7.5% of metakaolin and 10% of
flyash) was 68.5MPa whereas for Mix M3
with 7.5% of metakaolin the 28 days strength
is 67 MPa.
The increased strength is due to high reactive
silica present in metakaolin concrete. The
maximum compressive strength of concrete in
combination with metakaolin is based on two
parameters that are the replacement level and
the age of curing. Comparison of compressive
strength for various mixes is shown in Fig. 1.
Compressive strength results
0
20
40
60
80
100
M1 M2 M3 M4 M5 M6 M7
Mix
Com
pre
ssive strength
(M
pa)
3 days
7 days
28 days
56 days
90 days
Fig 1 Compressive Strength Test Results
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
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The increase in compressive strength for the
HPC is 5.35 %, 10.66 %, 7.77%, 9.09 %,
11.07 % and 7.1% higher compared to control
specimens at the age of 28 days
• Use of metakaolin and flyash is
necessary in the production of high
performance concrete due to lower
binder ratio and better hydration of
cement particles.
• The optimum percentage is
metakaolin (7.5 %) and flyash (10%)
for getting maximum strength and is
obtained in M6 mix The 28 days
compressive strength for M6 mix is
68.5MPa.
• The compressive strength mainly
depends on metakaolin because of
excellent pozzolanic properties to
produce high strength concrete.
• Metakaolin concrete attains high early
strength than flyash and metakaolin
combined concrete.
TEST SETUP
In this test axial loading was applied using a
hydraulic jack of 500 kN. An Electronic load
cell of capacity 500 kN was used to measure
the applied axial loads and was monitored by
load indicator. Axial load was transmitted to
the column through steel plates and neoprene
pads are placed over it to provide hinge
condition. The column specimens are adjusted
so that the centre line of the axial load
coincides with column faces. One number of
50 mm range Linear Voltage Differential
Transducer (LVDT) were used to measure the
mid-height deflection of the short column
specimens, read in electronic monitors. Strain
is measured in the top, Middle and bottom in
one face of the column. A typical test setup is
shown in fig.3.
Fig 2 Reinforcement Detail of Long and Short Column
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
IJAET/Vol.II/ Issue I/January-March 2011/190-202
Fig 3Typical Column Test set up in loading Frame
Details Of Column Casting And Testing
Plywood moulds are used for casting the
columns. Before Casting, oil was applied on
all the surfaces of the moulds. Cover blocks
were placed inside the mould to give proper
cover to the reinforcement. Concrete was
mixed using a tilting type laboratory mixer and
was poured into the moulds in layers. The
concrete was well compacted and after 24
hours of casting, the specimens were removed
from the mould and cured under water for a
period of 28 days. After curing the columns
were tested under uniaxial compression. To
facilitate easy loading of the columns, all the
columns were provided with column heads
both at top and bottom ends. In this test axial
loading was applied using a hydraulic jack of
500 kN. The loads are measured in the
Electronic load cell of capacity 500 kN and
deflections are noted down in the
Displacement indicator. Axial load was
transmitted to the column through steel plates
and neoprene pads placed over it to provide
hinge condition and to uniformly distribute the
load over the column head.
The column is supported at the base with
rubber pads to provided hinged end condition
and packed with filling materials like sand.
The column specimens are adjusted so that the
centre line of the axial load coincides with
column faces. Throughout the test setup, care
was taken to ensure the load was applied as
concentrically as possible. The plumb bob was
used to keep the columns perfectly vertical,
however some eccentricities are unavoidable.
Three numbers of 50 mm range Linear
Voltage Differential Transducers (LVDT)
were used to measure the deflection at top,
middle and bottom of the long column
specimens read in electronic monitors. The
strain was measured in the middle for long
columns on the compression and tension faces
using a Demountable mechanical (DEMEC)
strain gauge.
DISCUSSIONS
Control Short Column (SC)
The first specimen tested was the control
column SC with 0 % Flyash and 0 %
replacement of cement. The axial load was
applied gradually in increments of 25 kN.
When the load reached 185 kN, first crack
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
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appeared at the column Head. As the load
increased, the cracks widened and propagated
around the initial crack. The maximum load
obtained for control column was 240 kN, at
which failure occurred at the column head due
to crushing of concrete with an explosive
sound. The ultimate load obtained in the test
was 25 % lesser than the theoretical load
carrying capacity of the column. This
necessitates adequate confining of transverse
reinforcement in HSC column with much
closer spacing. The spacing of lateral ties as
per IS 456-2000 cannot be applied in the case
of HSC columns. The test results for long
columns are listed in Tables 7.
Short Columns With Metakaolin
The metakaolin replaced columns SMKC1,
SMKC2 and SMKC3 showed similar
behaviour when axially loaded under the
loading frame. All the columns failed in
compression either by crushing of the concrete
core, together with the buckling of the
longitudinal reinforcement. The maximum
ultimate load of 256.5 kN was obtained for
SMKC3. The percentage increase in ultimate
load was 6.8 %. The other two specimens
showed an increase of 2.08 %, 5 %
respectively. The failure pattern of HSC short
columns are shown in figures 5 and 6.
Fig 4 Experimental Test set up for short
columns
Fig 5 Crushing of Concrete
Fig 6 Failure pattern in short columns
Fig 7 Test Set Up Of Control Columns
Short Columns With Metakaolin And
Flyash
The specimens SMKFC1,SMKFC2, SMKFC3
failed at loads 232 kN , 236.5 kN , 241 kN
respectively which are 9.4 %, 11.6 %, 13.7%
higher compared to compared to control
columns (LC).
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
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The tests conducted by Razvi and Saatcioglu
on 250 mm square HSC Columns indicate
premature spalling of cover concrete occurred
in most of the column specimens prior to
development of strains associated with
concrete crushing. It was hypothesized that the
presence of closely spaced longitudinal and
transverse reinforcement forming a mesh of
reinforcement produced a natural plane of
separation between the cover concrete and
core. The separation of this plane was
triggered by high compressive stresses
associated with HSC as well as the difference
in mechanical properties of cover and core
concretes. The load versus axial deformation
curves are given in Figures 8 and 9.
Table VI Short Column Test Results
Specimen
Details
% Of
HRM
% Of
Flyash
First Crack
load (kN)
Ultimate
Load (kN)
Axial deformation at
Ultimate Load (mm)
SC1 0 0 185 240 1.35
SMKCI 5 0 193 245 1.32
SMKC2 7.5 0 201.5 252 2.45
SMKC3 10 0 207 256.5 2.15
SMKFC1 5 10 214 263 1.91
SMKFC2 7.5 10 220 265 2.04
SMKFC3 10 10 224 271 2.26
0
50
100
150
200
250
300
0 1 2 3 4
Column load (kN)
Axial deformation (mm)
SC
SMKC1
SMKC2
SMKC3
Fig 8 Axial Load – Deformation for columns with metakaolin
0
50
100
150
200
250
300
0 1 2 3
Axial Deformation (mm)
Load (kN) SC
SMKFC1
SMKFC2
SMKFC3
Fig 9 Axial Load – Deformation for columns with metakaolin and Fly ash
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
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DISCUSSIONS
Control Long Column (LC)
The first specimen tested was the control
column LC cast with normal concrete. The
axial load was applied gradually in increments
of 25 kN. When the load reached 150 kN, first
crack appeared at the column Head. As the
load increased, the cracks widened and
propagated around the initial crack. The
maximum load obtained for control column
was 212 kN, at which failure occurred at the
column head due to crushing of concrete. The
ultimate load obtained in the test was 24 %
lesser than the theoretical load carrying
capacity of the column. The long columns
with slenderness ratio 15, failed suddenly with
an explosive sound. Mau. S.T., et.al., (1998)
reported HSC columns has some intrinsic
disadvantages , one among them being the
extreme brittleness which imparts quality of
less ductility causing the structural members to
fail suddenly. The brittle nature of HSC can be
controlled by suitably confining the concrete
in compression zone. External confinement
can be provided by wrapping of the column
heads with GFRP strands.
Long Columns with Metakaolin
The metakaolin replaced columns LMKC1,
LMKC2 and LMKC3 showed similar
behaviour when axially loaded under the
loading frame. All the columns failed in
compression either by a shear band forming
diagonally across the section or crushing of the
concrete core, together with the buckling of
the longitudinal reinforcement. The maximum
ultimate load of 228 kN was obtained for
LMKC3. The percentage increase in ultimate
load was 7.5%. The other two specimens
showed an increase of 3.06%, 5.2%
respectively.
Long Columns with Metakaolin and Fly ash
The specimens LMKFC1, LMKFC2,
LMKFC3 failed at loads 232kN, 236.5kN,
241kN respectively which are 9.4%, 11.6%,
13.7% higher compared to compared to
control columns (LC). This type of failure is
similar to the studies of Tobay ozbakkaglu
and Murat Saatcioglu, in which the in place
strength of HSC experimentally recorded
column capacities are consistently over
estimated by the theoretical load calculations
unless the column is confined by properly
designed reinforcement. Chien- Hung Lin et
al., (2004) concluded that High Workability
Concrete Columns have higher stiffness, better
ductility and crack control ability than normal
concrete columns.
A decrease in concrete strength, increase of
longitudinal reinforcement, increase of
transverse reinforcement strength, and
decrease of transverse reinforcement spacing
improve the ductility of confined concrete and
columns effectively. The failure patterns in
HSC long columns are shown in figures 11
and 12. The load- deflection characteristics are
shown in figures 13 and 14. The moment-
curvature curve showing the comparison for
all long columns is in fig 15.
Table VII Long Column Testing Results
Specimen Details % Of HRM % Of
Flyash
First Crack
load (kN)
Ultimate
Load (kN)
Deflection at
Ultimate Load (mm)
LC1 0 0 155 212 9.4
LMKCI 5 0 162 218.5 10.58
LMKC2 7.5 0 168.5 223 11.2
LMKC3 10 0 186 237 11.5
LMKFC1 5 10 179 232 10.2
LMKFC2 7.5 10 181.4 236.5 12.02
LMKFC3 10 10 193 240 11.63
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
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Fig 10 Test Set Up Of Control Columns
Fig 11 Crushing Failure at column head
Fig 12 Base Shear Failure
0
50
100
150
200
250
0 5 10 15
Axial load (kN)
Mid Height Deflection (mm)
LC
LMKC1
LMKC2
LMKC3
Fig 13 Load – Deflection Curves for Metakaolin Columns
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
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0
50
100
150
200
250
300
0 2 4 6 8 10 12
Axial load (kN)
Mid Height Deflection (mm)
LC
LMKFC1
LMKFC2
LMKFC3
Fig 14 Load – Deflection Curves for Metakaolin and Fly ash Columns
0
1
2
3
4
5
6
0 1 2 3 4 5 6
Moment (kNm)
curvature ( x 10 ^-6) rad/mm
LC
LMKC1
LMKC2
LMKC3
LMKFC1
LMKFC2
LMKFC3
Fig 15 Moment – Curvature Characteristics for Long columns
Ductilty Parameters
It is the ability to sustain inelastic deformation
without substantial decrease in the load
carrying capacity. This can be defined with
respect to strains, rotations, curvatures or
deflections. Strain based ductility definition
depends almost exclusively on the material;
while rotation or curvature based ductility
definition also includes the effects of shape
and size of the cross section.
Displacement ductility,
µ∆ = ∆u ⁄ ∆y
where, ∆y is the yield deformation
corresponding to yielding of the reinforcement
in a cross section and ∆u is the ultimate
deformation beyond which the force
deformation curve has a negative slope.
Curvature ductility,
µφ = φu ⁄ φy
Where φy is the curvature corresponding to a
major deviation from the linear M-φ curve for
a member and φu is the curvature beyond
which the M-φ curve has a negative slope.
Ductility Index = µφ/ µ∆
It is defined as the ratio of curvature ductility
and displacement ductility.
The Displacement Ductility, the Curvature
ductility and Ductility Index values are listed
in Tables 8, 9 and 10 respectively. Ductility
Index for HSC columns is shown in fig 16.
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
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Table VIII Displacement Ductility
Column Details
Ultimate
Displacement ∆u ( mm)
Yield Displacement
∆y mm
Displacement Ductility
µ∆ = ∆u/ ∆y
LC 9.4 3.09 2.92
LMKC1 10.58 3.1 3.41
LMKC2 11.2 3.04 3.68
LMKC3 11.5 2.62 4.37
LMKFC1 10.2 2.12 4.81
LMKFC2 12.02 2.21 5.06
LMKFC3 11.63 2.54 4.72
Table IX Curvature Ductility
Column Details Ultimate Curvature
φu ( x 10-6) rad/mm
Yield curvature
φy ( x 10-6) rad/mm
Curvature Ductility
µφ = φu / φy
LC 4.29 1.025 4.4
LMKC1 4.19 1.157 4.85
LMKC2 4.51 1.162 5.24
LMKC3 4.12 1.48 6.1
LMKFC1 4.25 1.6 6.8
LMKFC2 4.67 1.755 8.2
LMKFC3 4.26 2.24 9.5
Table X Ductility Index
Column Details Displacement Ductility
µ∆
Curvature Ductility
µφ
Ductility Index
µφ/ µ∆
LC 2.92 4.4 1.5068
LMKC1 3.41 4.85 1.4222
LMKC2 3.95 5.24 1.3265
LMKC3 4.37 6.1 1.3958
LMKFC1 4.81 6.8 1.41372
LMKFC2 5.06 8.2 1.6205
LMKFC3 4.72 9.5 2.0127
Ductility Index
00.51
1.52
2.53
3.54
4.55
5.5
4.4 4.85 5.24 6.1 6.8 8.2 9.5
Curvature Ductility (µφ)
Deflection Ductility (µ∆)
Fig 16 Ductility Index for HSC columns
International Journal of Advanced Engineering Technology E-ISSN 0976-3945
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CONCLUSION
• Higher strength development is due to
pozzolanic reaction and filler effects of
metakaolin.
• Fresh concrete containing fly ash and
metakaolin is more cohesive and less
prone to segregation.
• Improved packing contributed by the very
small size of the particles of metakaolin
will improve the contact surface and thus
the bond between fresh metakaolin
concrete and the substrate namely
reinforcement, aggregates and old
concrete.
• The optimum percentage of metakaolin
and flyash for getting maximum strength
is 7.5% and is obtained in M6 mix.
• The compressive strength of high
performance concrete containing 7.5% of
metakaolin is 12% higher than the normal
concrete. As the age of concrete increases,
the compressive strength also increases.
Addition of metakaolin increases the
brittleness of the concrete.
• The use of mineral admixtures such as fly
ash and metakaolin, results in denser
microstructure of the concrete matrix
which enhance the durability properties.
Rate of water absorption of the test
specimens are lower compared to that of
specimens with normal concrete.
• The HSC short columns failed due to
crushing of concrete with an explosive
sound. The load carrying capacity of the
short columns increased with the increase
in percentage of admixtures. .The
maximum ultimate load was obtained for
SMKFC3 (271 kN) which is about 24 %
lesser than the estimated load.
• This is in agreement with the findings of
Mau. S.T., et al., 1998 that the High
strength concrete columns show sudden
failure with explosive sound which is due
to extreme brittle nature of HSC. The
brittleness can be completely eradicated by
suitably confining the concrete in the
compression zone It gives lateral
confinement to the core so that axial
compressive strength and ductility is
improved.
• The HSC long columns showed spalling of
cover concrete and with the incremental
load buckling phenomenon was observed
but failed ultimately due to crushing of
concrete in the Compression zone. The
maximum ultimate load was obtained for
LMKC3 at 237 kN which is about 20 %
lesser than the theoretical ultimate load.
Adequate confining of the column can be
done to improve the load carrying capacity
and ductility of the brittle HSC columns.
• Compressive strength Indices are
calculated for both long and short columns
and stiffness values are obtained for short
columns.
• The Ductility parameters namely
Displacement Ductility, Curvature
Ductility are show appreciable increase
compared to normal concrete columns.
ACKNOWLEDGEMENT
The Authors greatly acknowledge the VLB
Janakiammal College of Engineering and
Technology, Coimbatore for their support and
motivation for carrying out this research.
REFERENCES
1. K.E.Hassan, J.G. Carbera, R.S.Maliehe, “The
Effect Of Mineral Admixtures On the
Properties Of High Performance Concrete”,
Cement and Concrete Composites, 22 2002,
pp. 267-271,2002.
2. Chien-Hung lin , Shih-Ping lin, and Chih-Han
Tseng , “High workability concrete columns
under concentric compression”, ACI Structural
Journal, Vol. No. 101, No.1, pp. 85-93, Jan-
Feb 2004,.
3. Patrick Paultre, “Influence of concrete strength
and transverse reinforcement yield strength on
behaviour of High strength columns”, ACI
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