India - Research Paper - Santosh - 021106
-
Upload
narayan-singhania -
Category
Documents
-
view
10 -
download
5
description
Transcript of India - Research Paper - Santosh - 021106
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 1 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
CHAPTER 5 EXPERIMENTAL PROGRAMME
5.1 Introduction:
The objective of this programme was to obtain experimental data of effect on
1. Workability
2. Compressive strength
3. Flexural strength
4. Split tensile strength
5. Modulus of elasticity
6. Poison’s ratio
The size of the specimen considered for comparative strength test was
(150x150x150) mm, for flexure strength - (100x100x500) mm, for modulus of
elasticity and poison’s ratio tests- cylinders of 150mm dia and 300mm height
moulds. The cement was replaced by RHA by 5%, 10%, 15%, 20% by volume
of cement taken.
Table 5.1 Materials used for the tests:
Material Source
1. Cement Ultra -Tech Cement ( Grasim Industries )
2. Aggregate Bijapur Local quarry ( Trap )
3. Sand Bhima river Bed Bijapur Dist. )
4. Rice Husk Ash N.K. Enterprises, Jhurusguda ( Orissa )
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 2 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
5.2 EXPERIMENTAL DETAILS:
5.2.1 Mix design details
To compare the changes in the properties of concrete and to study the
performance of Rice husk ash, the following design mixes and percentages of
rice husk ash have been considered.
% of RHA by weight of cement – 10 , 15, 20, 25 %
Table 5.2 Mix Design Details:
Mixes Proportions W/C ratio
Cement
(Kg/ m3)
Sand
(Kg/m3) Aggregate (Kg/m3)
I 1:1.47:2.77 0.45 412 628.92 (36%) 1141.24
II 1:1.25:2.58 0.4 463.5 582.87(34%) 1198.12
III 1:1.06:2.62 0.35 480 510.17(30%) 1257.79
Superplasticizer used – Conplast SP430 – 1 % by weight of Cement.
5.2.2 Aggregate properties
The aggregates of size 20 mm and below are used for the tests. The
properties are as follows.
Water absorption - 0.42 %
Specific gravity – 2.8
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 3 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
Table 5.3 Grading of aggregates confirming to IS: 383 – 1970
IS Designation mm % Passing for graded aggregate of nominal % Selected
80 --
63 -- --
40 100 100
20 95-100 95
16 -- --
12.5 -- --
10 25-55 40
4.75 0-10 05
2.36 -- --
5.2.3 Cement properties Cement used for the test – Ultra tech cement
Table 5.4 Properties of Cement:
S.No Characteristics test results IS-8112-1989 specifications
1 Fineness 6.9 < 10
2 Specific Gravity 3.1 --
3 Standard consistency (%) 32 --
4 Initial Setting time (min) 47 > 30
5 Final Setting time (min) 110 < 600
6 Compressive strength (MPa)
3 days 24.5 > 23
7 days 38.45 > 33
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 4 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
5.2.4 Sand properties
The sand used for the test confirms to Grade – III of Is: 383 – 1970
Specific Gravity of sand – 2.65
Table 5.5 The grading of aggregate:
IS Sieve (mm) % Passing of sand taken % Passing for Grade - III
10 100 100
4.75 100 90 -100
2.36 100 85 - 100
1.18 86 75 - 100
0.6 61 60 - 79
0.3 27 12. - 40
0.15 5.5 0 - 10
5.2.5 RHA specifications.
Table 5.6 Minimum Guaranteed Specifications for Rice Husk Ash
SiO2 - Silica 85 % minimum
Humidity 2 % maximum
Particle size 25 microns average
Colour Grey
Loss on ignition at 800°C 4 % maximum
Ph value 8
5.2.6 Superplasticizer details
superplasticizer – Conplast SP430 ( FOSROC Chemicals)
Description: Conplast SP430 is based on sulphonated Napthalene Polymers
and supplied as a brown liquid instantly dispersible in water. Conplast SP430
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 5 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
has been specially formulated to give high water reductions up to 25% without
loss of workability or to produce high quality concrete of reduced permeability.
Standard compliance: Conplast SP430 complies with IS:9103:1999 and
BS:5075 part 3. Conplast SP430 conforms to ASTM-C-494 Type F and Type
A depending on the dosage used.
Properties: Specific Gravity 1.220 to 1.225 at 30 degrees
Chloride contents Nil to IS: 456
Air entrainment Approx 1% additional air is entrained
Compatibility: can be used with all types of cement except high alumina
cement. Conplast SP430 is compatible with other types of Fosroc admixtures
when added separately to the mix. Site trials should be carried out to optimize
dosage.
Workability: can be used to produce flowing concrete that requires no
compaction. Some minor adjustment may be required to produce high
workable mix without segregation.
Cohesion: Cohesion is improved due to dispersion of cement particles thus
minimizing segregation and improving surface finish.
Compressive strength: Early strength is increased up to 20% if water
reduction is taken advantage of. Generally, there is improvement in strength
up to 20% depending upon W/C ratio and other mix parameters.
Durability: Reduction in W/C ratio enables increase in density and
impermeability thus enhancing durability of concrete.
Dosage: The rate of addition is generally in the range of 0.5-2.0 litres/100 Kg
of cement.
Uses: To produce pumpable concrete, to produce high strength, high grade
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 6 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
concrete M30 and above by substantial reduction in water resulting in low
permeability and high early strength and to produce high workability concrete
requiring little or no vibration during placing.
Procedure for Specimen Preparation.
The different ingredients of Concrete Viz. Cement, sand & aggregates
were weighed according to the proportions. All these ingredients were
thoroughly dry mixed in the drum mixture. To this dry mix RHA was added
and dry mixed. To this dry mix the calculated amount of water was added and
thoroughly mixed at this stage superplasticizer was also added at slow rate.
This homogeneous concrete mix was filled into the concrete moulds, which
wee then kept on the vibrating table for vibration. After vibration the
specimens were smoothly finished. After 24 hours the specimens were
removed and transferred to the curing tank, where in they wee allowed to cure
for 3, 7 and 28 days. Then specimens were tested for their respective
strength.
5.3 COMPRESSIVE STRENGTH TEST: ( IS: 516 )
The specimen shall be cubical in shape of size 15 x 15 x 15 cm, if the
largest nominal size of the aggregate does not exceed 20 mm.
Procedure:
1. Sampling of material
2. Preparation of material
3. Proportioning of material
4. Weighing
5. Mixing of concrete
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 7 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
6. Compacting – Compacting has been done by mechanical vibrator
7. Curing-
8. Testing - testing machine – compression testing machine
9. Age of test – tests shall be made at recognized ages of the test
specimens
10. Number of specimens – at least 3 specimens required.
11. Placing of specimen in the testing machine – In the case of cubes, the
specimen shall be placed in the machine in such a manner that the
load shall be applied to opposite sides of the cubes as cast, i.e. not to
the top and bottom.
12. Calculation: the measured compressive strength of the concrete
specimen shall be calculated by dividing the maximum load applied to
the specimen during the test by cross sectional area, calculated from
the mean dimension of the section and shall be expressed to the
nearest N/mm2.
Maximum Load applied
Compressive strength =
Cross sectional area
5.4 SPLIT TENSILE STRENGTH OF CONCRETE. ( IS – 5816-1999 )
The cylinder specimen shall have diameter not less than four times the
maximum size of coarse aggregate and not less than 150mm. For routine
testing specimen shall be cylinder 150mm in diameter and 300 mm long.
Procedure:
1. Sampling of material
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 8 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
2. Preparation of material
3. Proportioning of material
4. Weighing
5. Mixing of concrete
6. Compacting – Compacting has been done by mechanical vibrator
7. Curing-
8. Testing - testing machine – compression testing machine
9. Age of test – tests shall be made at recognized ages of the test
specimens
10. Number of specimens – at least 3 specimens required.
11. Placing of specimen in the testing machine- the test specimen shall be
placed in the centering jig with packing strip carefully positioning along
the top and bottom of the plane of loading of the specimen. The jig
shall then be placed in the machine so that the specimen is located
centrally.
12. Calculation – the measured splitting tensile strength of the specimen
shall be calculated to the nearest 0.05 n/mm2 using the following
formula
fct = 2 p / π ld
where,
p = maximum load in Newton
l = length of the specimen
d = cross sectional dimension
5.5 COMPACTION FACTOR TEST:
It is more precise and sensitive than the slump test and is particularly
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 9 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
useful for concrete mixes of very low workability as are normally used when
concrete is to be compacted by vibration. This test works on the principle of
determining the degree of compaction achieved by a standard amount of work
done by allowing concrete to fall through a standard height.
The sample of concrete to be tested is placed in the upper hopper up
to brim. The trap door is opened so that the concrete falls into the lower
hopper. The trap door of the lower hopper is opened and the concrete is
allowed to fall into the cylinder. The excess concrete remaining above the top
level of the cylinder is then cut off with the help of plane blades. The concrete
is filled up exactly up to the top level of the cylinder. I is weighed to the
nearest 10 gms. The cylinder is emptied and then refilled with concrete from
the same sample in layers approximately 5 cm deep. The layers are heavily
rammed or vibrated so as to obtain full compaction. The top surface is struck
off and is weighed.
Then,
Weight of partially compacted concrete
Compaction Factor =
Weight of fully compacted concrete
5.6 LATERAL EXTENSOMETER: ( IS: 516 )
Introduction:
The equipment is designed to measure the lateral extension of 15 cm dia x 30
cm high concrete cylinder specimen tested for compression. The deformation
of the diameter ( lateral extension) is indicated on a dial gauge 0.002 x 12
mm. the dial gauge reading are 2.5 times the actual extension in the
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 10 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
specimen and hence the observed readings are to be divided by 2.5 to get the
actual extension.
Description:
It consists of 2 semicircular dial gauge frames, which are pivoted at the
fulcrum screw. 4 no of hardened and tapered end screws are fitted
diametrically opposite for holding the extensometer on to the specimen. The
ratio of the distance from the center if the frame to the center of the fulcrum
and distance between the centers of the dial gauge spindle and the center of
the fulcrum is 1:2.5 thus the dial gauge shows the reading 2.5 times the actual
extension.
A spacer strip is provided to fix the extensometer to the specimen and
to initially set the dial gauge. the spacer strip is kept in position with the help
of thumb screws. a spring is provided to keep the tip of the dial gauge in
contact with anvil. the tension of the spring can be adjusted with the help of
the spring adjustment nut.
Setting up of and Test procedure:
Keep the spacer strip in a position with the help of the thumbscrews. Adjust
the spring adjustment nut so that there is very little spring tension. Place the
concrete cylinder 15 x 30 cm and keep the extensometer midway of the
concrete cylinder along its height. Tighten the screws in a way that the
specimen is held by the extensometer diametrically with the axis of the
extensometer. Lock the screws in position with the help of the locking nuts.
Keep the specimen in the compression-testing machine. Adjust anvil so
that the dial gauge spindle is in the upper most position. Lock the anvil and
take the dial gauge reading. Remove the spacer strip by unscrewing the
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 11 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
thumbscrews. See that the dial gauge is not disturbed. if it is disturbed, initial
reading should be taken again.
Start applying compression load across the two faces of the cylinder.
Record the dial gauge reading at different loads until the specimen fails.
Calculate lateral extensometer of the specimen by dividing the dial
gauge reading by 2.5.
5.7 LONGITUDINAL COMPRESSOMETER:
The equipment has been fabricated for determination of the strain and
deformation characteristics of cement concrete cylinder of 15cm dia x 30 cm
long. a dial gauge of 0.002 x 12 mm is fixed. Due to the pivot, the
compression readings are magnified twice and to get the actual deformation
of the specimen, the observed readings of the dial gauge are to be divided by
two.
Description:
The compressometer consists of two frames for clamping to the
concrete specimen by means of five tightening screws having hardened and
tapered ends. The bottom frame is tightened to the specimen with three
tightening screws placed at 120 degrees. The top frame has two tightening
screws placed diametrically opposite. The two frames are held in position by
means of two spacers. Spacer screws are provided to fix the spacers to the
frame. The center distance of the tightening screws of the bottom and top
frame is 20 cm. a pivot rod rests on pivot screws. The pivot rod can be
adjusted, to get the proper friction between the rod and its supports, by
adjusting and locking the pivot screws. a spring provided so that the pivot rod
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 12 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
is always in contact with the pivot screws. Ball chain is provided to adjust the
tension of the spring. the spring loading clips are fixed to the top and bottom
frames. A dial gauge of 0.002 x 10mm is fixed to a bracket fitted to the top
frame. The dial gauge spindle rests on an adjustable anvil. the distances from
the center of the frame to the center of the pivot rod and center of the dial
gauge spindle are equal. So the dial gauge will be showing twice the actual
deformation.
5.7.1 SETTING UP AND TEST PROCEDURE:
Assemble the top and bottom frame by keeping the spacers in position. Keep
the pivot rod on the screws. Adjust the screws and lock them in position. Keep
the tightening screws of the bottom and top frame unscrewed (but not
completely)
Keep the specimen on a level surface. Keep the compressometer
centrally on the specimen so that the tightening screws of the bottom and top
frame are at an equal distance from the two ends. Screw the tightening
screws so that the compressometer is held on the specimen. Remove the
spacers by unscrewing the spacer screws.
Keep the specimen with compressometer centrally on the lower platen
of the compression-testing machine. Set the dial gauge and take the initial
readings. start applying load at a uniform rate. go on noting the dial gauge
readings at different loads until the specimen fails.
Actual deformation = observed reading / 2
5.8 TEST FOR FLEXURAL STRENGTH OF CONCRETE ( IS: 516 )
Size of the specimen: (10 x 10 x 50) cm
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 13 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
Apparatus: Beam mould: beam mould confirming to IS: 10086 - 1982 ,
vibrator, Universal Testing Machine
Procedure: Test specimens stored in water at a temperature of 24 - 36o C
shall be tested immediately on removal from the water while they are still in
wet condition. The dimension of the specimen shall be noted. no preparation
of the surface is required.
Placing the specimen in the testing machine: the bearing surfaces of
the supporting and loading rollers shall be wiped clean and any loose sand or
other material removed from the surfaces of the specimen where they are to
make contact with rollers. The specimen shall be then spaced in the machine
in such a manner such that the load shall be applied to the upper most
surface as cast in the mould along two lines spaced at 13.33 cm apart. The
axis of the specimen shall be carefully aligned with the axis of the loading
device. No packing shall be used between the bearing surfaces of the
specimen and the rollers. The load shall be applied without shock and
increasing continuously at a rate such that the extreme fiber stress increases
at approximately 180 kg/min. the load shall be increased until the specimen
fails and the max load applied to the specimen during the test shall be
recorded. the appearance of the fractured faces of the concrete and many
unusual features in the type of the failure shall be noted.
Calculation:
The flexural strength of the specimen shall be expressed as the modulus of
rupture fb, which, if 'a' equals the distance between the line of fracture and the
nearer support, measured on the centerline of the tensile side of the
specimen, in cm, shall be calculated to the near 0.5 Kg/ cm2 as follows
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 14 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
fb = (p x l) / ( b x d2)
when a is greater than 13.3 cm for 10 cm specimen
fb = (3 xp x a) / ( b x d2)
when a is less than 13.33 cm but grater than 11 cm for 10 cm specimen
where b = measured width in cm of the specimen
d = measured depth in cm of specimen at the point of failure
l = length in cm of the span on which the specimen was supported and
p = max load in Kg applied to the specimen
if a is less than 11 cm for 10 cm specimen the results of the test shall be
discarded.
5.9 POISON’S RATIO Poison’s ratio = lateral strain / longitudinal strain
5.10 MODULUS OF ELASTICITY
Modulus of Elasticity = longitudinal stress / strain
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 15 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
CHAPTER 6
TEST RESULTS AND DISCUSSION The following table shows the different test results of concrete containing Rice
Husk Ash as an admixture.
6.1 COMPACTION FACTOR
Compaction factors of MIX – II
MIX – II Proportion - 1:1.25:2.58
W / C ratio – 0.4
Superplasticizer – Conplast SP 430 – 1 % by weight of cement
Table 6.1 Compaction factors:
S. No % of RHA Compaction Factor
1 0 0.91
2 5 0.86
3 10 0.81
4 15 0.77
5 20 0.73 Workability was checked by compaction factor test the results of the
same are represented in Table 6.1 which range from 0.91 – 0.73. Compaction
factor goes on reducing as addition of RHA increases. Workability reduces
with addition of R.H.A. This is mainly due to the large surface area of RHA
which is in the range of 50 – 100 m2/ gm. Large addition would produce dry or
unworkable mix unless water reducing admixture or superplasticizers are
used. Due to absorptive character of cellular RHA particles, concrete
containing RHA require more water for a given consistency. [ 5 ] by addition of
25% of RHA it is difficult to get any workability, hence superplasticizer is must
whenever we replace cement by RHA as an mineral admixture. G.Roddiguez
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 16 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
De Sensale reported that at all the replacement levels the RHA concrete
require more superplasticizers compared to controlled concrete to obtain
desired slump which is due to high specific area of RHA [12].
6.2 COMPRESSIVE STRENGTH Table 6.2 COMPRESSIVE STRENGTH: MIX I
COMPRESSIVE STRENGTH (N/mm2) RHA (%) 3 Days 7 days 28 Days
0 18.95 23.18 36.55 5 21.99 23.86 40.29
10 20.92 26.32 38.43 15 18.37 23.18 37.81 20 18.70 21.85 37.20
0
5
10
15
20
25
30
35
40
45
0 5 10 15 20% of RHA
Com
pres
sive
stre
ngth
( N
/mm
2)
3 days7 days28 days
Fig 6.1 Compressive strength V/S % of RHA - MIX I
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 17 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
Table 6.3 COMPRESSIVE STRENGTH: MIX II
COMPRESSIVE STRENGTH (N/mm2)
RHA (%) 3 Days 7 days 28 Days
0 20.73 26.33 40.35
5 25.62 27.77 45.95
10 24.52 29.37 44.66
15 20.66 27.25 42.85
20 20.26 24.88 41.07
0
5
10
15
20
25
30
35
40
45
50
0 5 10 15 20% of RHA
Com
pres
sive
Str
engt
h (N
/mm
2)
3 days7 days28 days
Fig 6.2 Compressive strength V/S % of RHA – MIX II
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 18 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
Table 6.4 COMPRESSIVE STRENGTH: MIX III
COMPRESSIVE STRENGTH (N/mm2)
RHA (%) 3 Days 7 days 28 Days
0 23.8 30.58 46.81
5 28.59 32.41 57.37
10 26.36 34.13 54.78
15 23.92 31.7 50.72
20 22.94 30.51 48.27
0
10
20
30
40
50
60
70
0 5 10 15 20% of RHA
Com
pres
sive
Str
engt
h ( N
/mm
2)
3 days7 days28 days
Fig 6.3 Compressive strength V/S % of RHA – MIX III
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 19 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
The cube specimens of Mix I, mix II and mix III were tested for
compressive strength as per IS:516, the results obtained are represented in
Table 6.2, 6.3 and 6.4 respectively. For addition of 5% of RHA there is an
increase in the compressive strength of concrete when compared to the
controlled concrete. The same has been produced below
Table 6.5 Percentage increase in compressive Strength
% Increase in compressive strength Mix No
3 days 7 days 28 days
I 16.04 11.54 20.15
II 13.55 11.54 10.41
III 10.23 13.87 22.55
The compressive strength test results shows that there is increase in
compressive strength for 5% replacement of cement by RHA. The increase in
strength is up to 22% in comparison with controlled concrete. Further, any
increase in RHA shows decreasing trend in compressive strength. From the
present study and literature reported it can be observed that there is an early
increase in strength of concrete containing RHA due to early pozzolanic
action, and also later strength (90 days). Because clinkering temperature of
RHA is 1500oC, polymorphism of silica such as quartz, tridymite and
cristobalite with open structured SiO2 in RHA is produced which can promote
pozzolanic action. There is no significant increase in 7 days strength. So we
can generalize that 5% addition of RHA can bring good results in compressive
strength.
The study carried out by Dr. P. K. Mehta reveals the same trend [5]
that compressive strength increases for addition of 5% RHA and reduces for
further increase in RHA.
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 20 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
The addition of RHA results in reduction in porosity of cement paste
and causes refinement in the pore structure. RHA absorbs large amount of
water due to its high specific area. This reduces bleeding of water. It improves
the weakest transition zone under the aggregate, however adding the correct
amount of RHA is important for achieving high strength [5]. The study
undertaken by other researchers like A.A.F shaheen [8], Mohan prasad
Aryal[7], Mr. Nehdi, J. Duquette, A. E. Damatty [10] has also indicated same
results. G, Rodriguez De Sensale and D.C.C Dal Molin have shown that
higher compressive strength can be obtained with lower W/C ratio with
addition of RHA.
6.2 SPLIT TENSILE STRENGTH
Table 6.6 SPLIT TENSILE STRENGTH: MIX I
SPLIT TENSILE STRENGTH ( N/mm2)
RHA (%) 3 Days 7 days 28 Days
0 1.69 1.93 2.73
5 1.81 2.04 3.02
10 1.49 2.08 3.09
15 1.24 2.14 3.32
20 1.23 1.88 2.96
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 21 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
0 5 10 15 20% of RHA
Tens
ile S
tren
gth
(N/m
m2)
3 days7 days28 days
Fig 6.4 Split Tensile strength V/S % of RHA – MIX I
Table 6.7 SPLIT TENSILE STRENGTH: MIX II
SPLIT TENSILE STRENGTH ( N/mm2)
RHA (%) 3 Days 7 days 28 Days
0 2.03 2.66 3.11
5 2.22 2.73 3.31
10 1.96 2.85 3.61
15 1.74 3.01 3.89
20 1.30 2.76 3.30
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 22 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
0 5 10 15 20% of RHA
TEns
ile S
tren
gth
(N/m
m2)
3 days7 days28 days
Fig 6.5 Split Tensile strength V/S % of RHA – MIX II
Table 6.8 SPLIT TENSILE STRENGTH: MIX III
SPLIT TENSILE STRENGTH ( N/mm2)
RHA (%) 3 Days 7 days 28 Days
0 2.10 3.18 3.25
5 2.29 3.32 3.65
10 1.74 3.4 3.82
15 1.63 3.61 3.92
20 1.48 3.23 3.43
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 23 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
0 5 10 15 20% of RHA
tens
ile S
tren
gth
(N/m
m2)
3 Days7 days28 Days
Fig 6.6 Split Tensile strength V/S % of RHA – MIX III
The cube specimens of Mix I, mix II and mix III were tested for split
tensile strength as per IS: 5816, the results obtained are represented in Table
6.6, 6.7 and 6.8 respectively. The increase in tensile strength compared to
controlled concrete is summarized below
Table 6.9 Percentage increase in tensile Strength
% Increase in tensile strength Mix No 3 days (5%) 7 days (15%) 28 days (15%)
I 8.7 10.88 21.61
II 9.35 13.11 25.08
III 9.04 13.52 20.62
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 24 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
From the present study it can be observed that there is an increase in
tensile strength in concrete containing RHA as an admixture. The increase in
tensile strength is up to 25% for addition of 15% of RHA. There is an early
increase in strength for addition of 5 % of HA. The 7 and 28 days strength is
increased considerably fore addition of 15% of RHA. This character may be
due to pore refinement of transition zone by the filler action of fine RHA, which
improves the weakest one under the aggregate. Another point is to be
observed that compressive strength has increased for 5% addition of RHA,
but tensile strength increased for 15% addition of RHA.
Study carried out by A.A.F. Shaheen shows that for addition of 10%
RHA tensile strength increased up to 44%. G. Rodrguez de Sensale and
D.C.C Dal Molins results shows that there is an increase in tensile strength for
20% replacement of RHA by weight [12]. Study carried out by Mr. Mohan
Prasad Aryal shows that there is increase in tensile strength of concrete for
addition of 15% of RHA.
6.4 FLEXURAL STRENGTH
Table 6.10 FLEXURAL STRENGTH: MIX I
FLEXURAL STRENGTH ( N/mm2) RHA (%) 3 Days 7 days 28 Days
0 2.65 3.27 4.12 5 2.99 3.53 4.14 10 2.9 3.57 4.18 15 2.65 3.67 4.38 20 2.6 3.32 3.93
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 25 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 5 10 15 20% of RHA
Flex
ure
Stre
ngth
(N/m
m2)
3 Days7 days28 days
Fig 6.7 Flexural strength V/S % of RHA – MIX I
Table 6.11 FLEXURAL STRENGTH: MIX II
FLEXURAL STRENGTH ( N/mm2)
RHA (%) 3 Days 7 Days 28 Days
0 2.80 2.9 4.41
5 3.16 2.94 4.40
10 3.06 3.27 4.46
15 3.02 3.39 4.74
20 2.89 2.90 4.28
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 26 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 5 10 15 20% of RHA
Flex
ure
Stre
ngth
(N/m
m2)
RHA3 Days7 Days28 Days
Fig 6.8 Flexural strength V/S % of RHA – MIX II
Table 6.12 FLEXURAL STRENGTH: MIX III
FLEXURAL STRENGTH ( N/mm2)
RHA (%) 3 Days 7 Days 28 Days
0 3.08 3.56 4.89
5 3.56 3.55 4.90 10 3.18 3.6 4.92 15 2.9 3.22 5.16 20 2.88 2.93 4.8
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 27 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
0
1
2
3
4
5
6
0 5 10 15 20% of RHA
Flex
ural
Stre
ngth
( N
/mm
2)
3 days7 days28 days
Fi6.9 Flexural strength V/S % of RHA – MIX III
The cube specimens of Mix I, mix II and mix III were tested for Flexural
strength as per IS:516, the results obtained are represented in Table 6.10,
6.11 and 6.12 respectively The increase in flexure strength of concrete with
RHA compared to controlled concrete is summarized below.
Table 6.13 Percentage increase in Flexural Strength
% Increase in flexural strength Mix No
3 days (5%) 7 days (15%) 28 days (15%)
I 12.80 12.2 6.3
II 2.80 16.89 7.5
III 6.30 7.40 5.5
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 28 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
By results it can be summarized that as in tensile strength results there
is an early increase in the flexural strength of concrete with 5% addition of
RHA this may be due to high pozzolanic action of RHA in early stages. But
later on the flexural strength increases up to 15% compared to controlled
concrete for 10 % addition of RHA. As silica is held in RHA in a non crystalline
state & micro porous structure the pozzolanic activity will be high. A.A.F.
Shaheen showed that there is an increase in flexural strength of 31% for 10 %
addition of RHA
6.5 LONGITUDINAL STRAIN Table 6.14 LONGITUDINAL STRAIN IN CYLINDRICAL SPECIMEN: MIX I
% RHA Strain in mm
0 0.00175
5 0.00185
10 0.0018
15 0.0018
20 0.0018
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 29 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
1.7E-03
1.7E-03
1.7E-03
1.8E-03
1.8E-03
1.8E-03
1.8E-03
1.8E-03
1.9E-03
0 5 10 15 20% OF RHA
STR
IN IN
Series1
Fig. 6.10 Longitudinal Strain V/S % of RHA – MIX I
Table 6.15 LONGITUDINAL STRAIN IN CYLINDRICAL SPECIMEN: MIX II
% RHA Strain in mm
0 0.00188
5 0.002
10 0.002
15 0.0021
20 0.00235
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 30 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
0.0E+00
5.0E-04
1.0E-03
1.5E-03
2.0E-03
2.5E-03
0 5 10 15 20% OF RHA
STR
IN IN
Series1
Fig. 6.11 Longitudinal Strain V/S % of RHA – MIX II
Table 6.16 LONGITUDINAL STRAIN IN CYLINDRICAL SPECIMEN: MIX III
% RHA Strain in mm
0 0.00193
5 0.002
10 0.0023
15 0.00235
20 0.00238
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 31 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
0.0E+00
5.0E-04
1.0E-03
1.5E-03
2.0E-03
2.5E-03
3.0E-03
0 5 10 15 20% OF RHA
STR
AIN
IN
Series1
Fig. 6.12 Longitudinal Strain V/S % of RHA – MIX III
6.6 MODULUS OF ELASTICITY Table 6.17 MODULUS OF ELASTICITY OF CONCRETE SPECIMENS
Modulus of Elasticity (GPa)
% of RHA Mix I Mix II Mix III
0 34.53 42.86 43.55
05 34.17 43.32 44.06
10 39.91 43.63 41.49
15 35.65 41.59 47.63
20 40.09 40.69 44.65
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 32 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
Fig 6.13 Stress-Strain curve Mix I
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
50.00
0.0000 0.0003 0.0006 0.0010 0.0012 0.0016 0.0019 0.0039 0.0063
strain
stre
ss (M
Pa)
Series1
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 33 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
Fig. 6.14 Stress-Strain curve Mix II
0.00
10.00
20.00
30.00
40.00
50.00
60.00
0.0000 0.0002 0.0006 0.0009 0.0012 0.0015 0.0019 0.0021 0.0023
srtain
stre
ss (M
Pa)
Series1
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 34 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
Fig. 6.15 Stress-Strain curve Mix III
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
0.0000 0.0002 0.0005 0.0007 0.0009 0.0011 0.0012 0.0013 0.0015 0.0017 0.0019 0.0020 0.0021 0.0023
strain
stre
ss( M
Pa)
Series1
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 35 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
The cylindrical concrete specimens of Mix I, Mix II and mix III were
tested to study the stress strain relationship. The stress-Strain curves are
presented in Fig.6.12- Fig 6.15.
Many researchers agree that high strength/performance concrete is
more brittle than normal strength concrete, such concrete develops a smaller
amount of cracking than normal strength concrete during all stages of loading,
in consequences, the ascending part of the stress strain curve is steeper and
linear up to a very high proportion of the ultimate strength. The descending
part of the curve is also very steep so that high strength concrete is more
brittle than ordinary concrete and explosive and sudden type of failure in
compression has often being encountered.
The stress- strain ratio at which micro-cracks begin to form continuous
crack pattern is higher for higher strength concrete, therefore the stress- strain
ratio at which stress- strain curve to curve more sharply to the horizontal is
higher for higher strength concrete. At maximum stress of 47.53, 48.67 and
62.25 N/mm2 of Mix I, Mix II and Mix III the corresponding strains are 0.0019,
0.0019 and 0.0018 respectively. It follows that the high strength concrete has
a higher modulus of Elasticity. According to IS 516 in the normal concrete the
cracks normally initiate at 30% of max or failure load. But in the present study
cracks initiated at 45% of the failure load. The failure occurred by the
mechanism of chipping of surfaces and vertical splitting of specimens parallel
to the loading direction. The stress strain curve showed linearity up to 45—55
% of the peak load.
Sudden and explosive type of failure is the indicative of the brittleness
of the material. The observed grater brittleness of high strength concrete to
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 36 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
that of normal strength concrete as reflected by its lesser amount of micro
cracking at all stress levels and smaller inelastic deformation is due mainly to
its greater homogeneity and there fore lesser stress concentrations. At low
and moderate stresses its smaller amount of bond cracking and therefore its
higher proportionality limit compared to normal strength concrete is due to
various reasons, namely, the smaller difference between the elastic modulie
of mortars and aggregate phases and higher bond strength of the aggregate
mortar interface, and the smaller total amount of interfacial areas that are
sensitive to local tensile or shear stresses [15].
6.6 POISON’S RATIO OF CONCRETE: Table 6.18 Poison’s Ratio of Mix – I
MIX I
% of RHA Poison's Ratio
0 0.200
5 0.163
10 0.176
15 0.170
20 0.196
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 37 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
Table 6.19 POISON’S RATIO OF CONCRETE SPECIMENS : MIX II
MIX II
% of RHA Poison's Ratio
0 0.150
5 0.200
10 0.156
15 0.170
20 0.170
Table 6.20 POISON’S RATIO OF CONCRETE SPECIMENS : MIX III
MIX III
% of RHA Poison's Ratio
0 0.155
5 0.172
10 0.195
15 0.180
20 0.175
The Values of Poison’s Ratio range from 0.15 to 0.20
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 38 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
CHAPTER 7 CONCLUSIONS
Based on the experimental studies carried out the following conclusions are
drawn:
1. The workability goes on reducing for every percentage increase of RHA
as an admixture and at 25% of addition of RHA, workability is difficult to
achieve even with the superplasticizer.
2. The compressive strength can be increased up to 22% by addition of 5% of
RHA when compared with controlled concrete. So addition of 5 % RHA can
give good results.
3. The compressive strength goes on reducing by adding more than 5% of
RHA but will not reduce beyond the strength for which controlled concrete is
designed.
4. It can be observed form the results that the increase in compressive
strength compared to normal concrete is 10.23, 13.87 and 22.55 % for W/C
ratio of 0.45, 0.4 and 0.35 respectively. So we can increase the strength by
reducing the W/C ratio i.e. we obtain better results for dense mix concrete.
5. Due to early pozzolanic reaction of RHA there is increase in 20.15% in
compressive strength when compared to controlled concrete at 3
days.
6. There is an increase in tensile strength up to 25% when compared
with controlled concrete
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 39 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
7. From the results it can be observed that there is 25% increase in tensile
strength for addition of 15% of RHA. Due to early pozzolanic reaction there is
increase of 10% in tensile strength at 3 days.
8. From the results it can be observed that there is only7% increase
in flexural strength when compared to controlled concrete.
9. As in tensile strength, the flexural strength increases for addition of 15% of
RHA. Due to early pozzolanic reaction there is an increase of 12% in the
flexural strength for addition of 5% of RHA.
10. From the results it can concluded that the modulus of Elasticity increases
with increase in characteristic strength of concrete. The modulus of elasticity
of Mix I, Mix II and Mix III are 40.13, 43.63 and 47.63 GPa respectively.
11. The proportionality limit of Stress-Strain curve obtained from the results
ranges from 50-60 % which is more than 40%, mentioned in the IS code.
12. The Poison’s Ratio obtained from the results for Mix I, Mix II and Mix III
varies from 0.15 to 0.20
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 40 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
CHAPTER 8 SCOPE FOR FUTURE INVESTIGATION
• The durability aspect of concrete with RHA as an admixture is to be
studied.
• The strength of concrete with RHA beyond 28 days can be studied
• Optimum percentage of RHA and superplasticizer can be done using
optimization techniques.
• The heat of hydration in concrete with RHA needs to be studied.
• The effect of setting time of concrete by addition of RHA can be
studied.
• The performance of RHA in concrete beyond M60 can be studied.
• The chloride penetration of concrete with RHA can be studied
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 41 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
REFERENCES
1. Coutinho J Sousa (2003), “The combined benefits of CPF and RHA in
improving the Durability of Concrete Structures”- Cement & Cement
Composits 25 p. 51-59
2. -------
3. Singhania Narayan P, “Rice Husk Ash” – N K Enterprises, Orissa
4. www.FHWA.Com / materials group
5. Satish Chandra (2002),” waste Materials used in concrete
manufacturing”, standard publication distributors- Delhi
6. N. Bouzounbaa and B. Faurnier, “Concrete Incorporating Rice-Husk
Ash: Compressive Strength and Chloride-ion penetrability”
7. Aryal Mohan Prasad (2002), “ Concrete with Rice Husk Ash as local
Mineral Admixture” http://www.prarup.com/concmpa.htm
8. A.A.F Shaheen “A comparison study for durability of mortars
containing Different pozzolanic materials” Lecturer Strength of
materials , Housing and Building Research center Giza Egypt
9. Rao Ram G.V, Rao Sheshagiri and Reddy Siva Sankar (2004),” High
Performance Rice Husk Ash Concrete- Mix Proprtioning using Design
Factor Method” Proceedings of International Conference on Advances
in Concrete and Construction, ICACC-2004 16-18 December,
Hyderabad, India p. 679- 690
10. M. Nehdi and J Duquette, A. El Damatty (2003), ” Performance of Rice
Husk ash Produced using a new technology as a mineral admixture in
concrete”, Cement & concrete research 33, P. 1203-1210
11. A.K. Tiwari, “ rice Husk Ash”, Sr. manager Technical, Borregaurd
India Ltd. Mumbai
12. G.Rodrighez de Sensale and D.C.C Dal Molin (2004), “Study of high
Performance Concrete regarding effect of Rice Husk Ash Substitution”
Aug 09 FR Hilton Head Marriott685 p. 02- 11
13. IS : 516-1959 ‘ Indian Standard- Methods of for Strength of Concrete’
BIS 2002
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 42 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
14. IS 5816 : 1999- Indian Standard Splitting Tensile Strength Of Concrete-
Method of Test, BIS, New Delhi
15. Khadiranaikar, R.B.,‘ Experimental Investigation of high Performance
concrete under repeated compressive loading’- Ph.D. Thesis, IIT- Delhi
16. IS: 10262-2000
17. AIM-373 Insrtuctions- lateral Extensometer AIMIL Ltd
18. AIM- 372 Instructions- Longitudinal Compressometer ,AIMIL Ltd
19. www.ricehuskash.com
20. Superplasicizing admixtures Conplast 430, FOSROC chemicals
21. K.E Kurtis and F.A. Rodrigues (2003) “ Early Age hydration of Rice
Hull ash Cement Examined by transmission soft X- ray microscopy”,
Cement & Concrete Research 33 P. 509-515
22. Rao Shrinivas p and Sravana (2005), “ Relationship between Splitting
Tensile and Compressive Strength of Concrete” - CE & CR, June, P.
39-43
23. Measuring Chloride penetration resistance- Henry G. Russel- concrete
products
24. Relative efficiencies of different concrete mix proportioning methods-
T.S. Nagaraj and Zahida banu
25. IS: 456-2000, Indian Standard for Plain and Reinforced Concrete –
Code of Practice, BIS, New Delhi
26. IS: 383
27. [email protected] – study of HPC regarding the effect of
RHA substitution
28. Neville A.M [1996], “properties of concrete” 4th edition, Addison
Wesley Longman, ltd, UK
29. Civil Engineering Department, Civil engineering Materials laboratory,
CE305L – ‘ Static Modulus of Elasticity and Poison’s ratio of Concrete
In compression’. ASTM C469
30. Fuminori Tomosawa and TAkafumi Noguchi-‘Relationship between
compressive strength and modulus of elasticity of high strength
concret’. Dept. of Architecture, Fac. Of Engineering, Uni. Of Tokyo
STUDY ON THE PROPERTIES OF CONCRETE CONTAINING RICE HUSK ASH AS AN ADMIXTURE
- 43 –
Dept. of CIVIL Engg. Basaveshwar Engineering College, Bagalkot
31. David Darwin (2000), “Concrete in Compression”. Bulletin of the M.I.C
of A.C.I, April- June
32. Mehta, P.K. (1986), “Structure, Properties, and Materials”, Englewood
Cliffs, NJ: Prentice-Hall.
33. Mehta, P.K. (1994), “Rice-husk Ash - A unique Supplementary
Cementing Material”, Ad9 in Concrete Technology, MSL Report 94-1
(R), CANMET, pp. 419-444. (ed. V.M. Malhotra).
34. Mehta, P.K. (1978), “Siliceous Ashes and Hydraulic Cements Prepared
Therefrom”, Belgium Patent 802909, July 1973, U.S. Patent 4105459,
Aug.
35. Pitt, N. (1976), “Process for Preparation of Siliceous Ashes”, U.S.
Patent 3959007, May.
36. Mazlum, F., and Uyan, M. (1992), “Strength of Mortar Made with
Cement Containing Rice-husk Ash and Cured in Sodium Sulphate
Solution”, ACI-SP 132 , pp. 513-531. (ed. V.M. Malhotra).
37. Al-Khalaf, M.N., and Yousif, H.A. (1984), “Use of Rice-husk Ash in
concrete”, Journal of Cmenet Composites, Vol. 6, pp. 241-248.
38. Zhang, M.H., and V.M. Malhotra, (1996), “High-Performance Concrete
Incorporating Rice-husk Ash as a Supplementary Cementing Material”,
ACI Materials Journal, Vol. 93, No. 6, pp. 629-636.
39. Mehta, P.K. (1994), “Highly Durable Cement Products Containing
Siliceous Ashes”, U.S. Patent No. 5, 346, 548, Sept. 13, Vances