correlation of index properties with the cbr values of soils with and without...
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50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
CORRELATION OF INDEX PROPERTIES WITH THE CBR VALUES OF SOILS
WITH AND WITHOUT ADMIXTURES
Dr.H.S.Prasanna 1, Professor, NIE, Mysuru, [email protected]
Sindhu V 2, Student, NIE, Mysuru, [email protected]
SatishUppin 3, Student, NIE, Mysuru, [email protected]
Ezhilan Ashok V 4, Student, NIE, Mysuru, [email protected] Mohan G.K 5, Student, NIE, Mysuru, [email protected]
ABSTRACT: In the present experimental study, six field soils having different clay mineralogical compositions
were selected. The physical properties of the soils were determined as per BIS specifications. The compaction
characteristics of the soils at different energy levels i.e. SP, MP, RSP, RMP were determined. Keeping the fly ash
content as 20% by weight of soil, the amount of RBI Grade 81 is varied from 2% to 6% by weight of the soil. The
CBR tests were conducted on compacted plain soils and soils having 20% fly ash and varied percentage of RBI
Grade 81(2, 4 and 6%) with soaked conditions. It was observed from the experimental results that, WL, WP, PI of
the plain soil could be better related with CBR values in comparison with soils with admixtures and without
admixtures. It was also found that the optimum value of CBR was obtained for the mix proportion of 4%RBI and
20% fly ash. It is also evident that CBR values are having better correlation with index properties and compaction
characteristics of the soil with 2% RBI and 20% fly ash.
Keywords: admixtures, CBR value, clay mineralogy, energy levels and index properties.
INTRODUCTION
The development of any country can be monitored
by the progress in infrastructural facilities, with
particular reference to transportation. Large scale
road constructions are being developed over the
length and breadth of the country due to adoption
of highly intensified activities in road construction
by Central and State Governments like PMGSY
(Pradhan Mantri Gram Sadak Yojana), Golden
Quadrilateral to name a few. Almost the entire road
network consists of flexible pavements. It is
particularly observed that, the quality and
durability of flexible pavements is greatly affected
by the type of sub-grade soil over which pavements
are to be constructed. The durability of pavement
predominantly depends upon the characteristics of
sub-grade which provides the base for such
pavement structure. For the design of flexible
pavements CBR value is one of the important
parameter. It is often observed that CBR values are
determined in the laboratory as well as in the field
(to a little extent) by obtaining the
undisturbed/remoulded soil samples. These
samples are obtained at suitable intervals as per the
guidelines laid by agencies like BIS, ASTM,
HMSO to name a few. It is observed that the
limited number of soil samples obtained as per the
guidelines laid by the agencies aforesaid may not
be the representative value for the entire length of
the road, due to the fact that the soil samples so
obtained may have variations in their engineering
properties due to variety of reasons. Hence, it is
always difficult for designers to obtain
representative CBR values for use in design of
flexible pavements, which can be avoided only by
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50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
taking large number of soil samples at short
intervals along the alignment. This necessities the
increase in large number of CBR tests to be carried
out in the laboratory which enhances the direct and
indirect increase in time and cost of the associated
infrastructure projects. This would result in serious
delay in the progress of the project. Any such delay
would add to project cost. It is also observed that
quality control of large number of soil samples is
also a difficult task. Hence it becomes necessary to
predict the CBR values more accurately by indirect
methods i.e. by using the established relationships
provided between various index properties and
CBR values.
Modification of the soils to improve their
engineering properties to the optimum levels at the
site plays a major role in practical situations. Well-
compacted soils increase the performance of the
soil by improving its shear strength and resistance
to settlement behavior. The compaction
characteristics of any soil are optimum moisture
content (OMC) and maximum Dry density (MDD).
Thus, the behavior of the coarse-gained soils and
fine-grained soils are entirely different altogether.
In order to increase the load carrying capacity of
the soil, stabilization is brought about. Stabilization
can be through addition of admixtures like fly ash,
RHA, moorum, lime, cow dung, RBI grade 81 etc.
These admixtures when added with the soil in
certain proportions bring about the stabilization.
The stabilization of soil is measured about in terms
of CBR.
LITERATURE REVIEW
Attempts have been made by several researchers to
establish relationship between index properties of
soils with compaction characteristics of fine-
grained soils, Nagaraj [1], Gurtug and Sridharan
[2]. Attempts have also been made by several
research workers to establish relation between
CBR with index properties of soil and compaction
characteristics i.e. γdmaxand OMC Venkataraman, et
al (1995)(3), Kumar, et al (2000)(4), Karunaprema
and Edirisinghe (2002)[05],to name a few. Vinod
and Cletus [06] established relationship between
CBR and liquid limit, maximum dry density and
suggested following correlation based on an
experimental study on lateritic soil,
𝐶𝐵𝑅 = −0.889 (WLM) + 45.616 --------- (1)
where WLM is modified liquid limit which is
given by
𝑊𝐿𝑀 = 𝐿𝐿 (1 − 𝐶/100) ----------- (2)
Where LL is the liquid limit on passing 425
micron sieve in percent where C is fraction of soil
coarser than 425 micron (percent).
Patel and Desai [07] proposed correlation between
CBR and plasticity index (PI), maximum dry
density (MDD) and optimum moisture content
(OMC) of soils under soaked conditions.
𝐶𝐵𝑅 𝑠𝑜𝑎𝑘𝑒𝑑 = − 43.907 − 0.093 𝑃𝐼 −
18.78 𝑀𝐷𝐷 − 0.3081 𝑂𝑀𝐶 −
− − −(3)
Where MDD is in gm/cc
Roy et.al., [08] proposed a method to predict the
value of soaked CBR in terms of optimum
moisture content (OMC) and maximum dry
density(MDD) of a soil which is given by,
𝐿𝑜𝑔 𝐶𝐵𝑅 = 𝐿𝑜𝑔 (𝛾𝑑𝑚𝑎𝑥/𝛾𝑤) − 𝐿𝑜𝑔 (𝑂𝑀𝐶) −
− − (4)
Where γdmax and γw are in the same unit
Suksun et al [09], based on their extensive
experimental study on fine-grained soil, lateritic
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50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
soils and crushed rocks established the relation
between maximum CBR values with maximum dry
density (MDD) given by equations 4 to 7 with the
degree of correlation greater than 0.85.
CBR max= γdmax-9.63 for fine grained soils
15 𝑘𝑁/𝑚3 < 𝛾𝑑𝑚𝑎𝑥 < 20 𝑘𝑁/𝑚3 ---(5)
CBR max= 2.95 γdmax-9.08 for laterite soils
19.5 𝑘𝑁/𝑚3 < 𝛾𝑑𝑚𝑎𝑥 < 21.5 𝑘𝑁/𝑚3---(6)
CBR max= 17.44 γdmax -276.76 for the crushed
rocks
22.2 𝑘𝑁/𝑚3 < 𝛾𝑑𝑚𝑎𝑥 < 22.8 𝑘𝑁/𝑚3---(7)
where γdmaxis expressed in kN/m3
They also reported that, CBR values can be
correlated with maximum CBR values given by
equation- 8 with a high degree of correlation of
0.94.
𝐶𝐵𝑅
𝐶𝐵𝑅𝑚𝑎𝑥= 4.95 −
𝛾𝑑
𝛾𝑑𝑚𝑎𝑥− 3.96 − −(8)
for 90% <γdmax< 100%
where CBRmax is the CBR value
corresponding to the maximum dry unit weight.
Relationship of soils having admixtures with
index properties and compaction
characteristics.
Attempts have been made by several researchers to
establish the relationship between CBR values of
soils with various admixtures with compactions
and index properties of soils.
Patil B.M., Patil K.A., [10,11] studied the effect of
pond ash and RBI Grade 81 on properties of sub-
grade soil and they found that the CBR value of
grade –III base course treated with 20% pond ash
and 4% of RBI Grade 81 is increased by 125.93%
as compared to untreated grade –III base course.
They concluded that, the geotechnical properties of
clayey soil improve significantly due to addition of
pond ash and RBI grade 81.
Haricharan et al [12] studied the effect of RBI
Grade 81 on black cotton soils and they found that
unconfined compression strength of specimens
treated with RBI-81 increased approximately by
250% for curing period of 28 days as compared to
virgin soil. Further the CBR value improved
approximately by 400%.The increase in CBR value
of treated soil increased by 400%.
Najia Nouf and Sureka Nagesh [13] studied the
effect of RBI 81 on properties of black cotton soil
and found that UCS of stabilized sample increases
with increase in period of curing. It was also found
that, increase in strength was more upon lime
addition, compared to addition of RBI.The
stabilizer RBI Grade 81 is effective in reducing the
plasticity characters. The soaked CBR values
increased three folds with addition of 6% stabilizer.
Lekha and Ravi Shankar [14] studied the effect of
RBI Grade 81 stabilized soils for pavements and
they concluded that, evidence for stabilization can
be seen from change in chemical composition of
soils when treated with stabilizer. The percentage
of calcium oxide, alumina and sulphates which are
important by products are increased on
stabilization.
MATERIALS AND METHODOLOGY
Materials
For the present experimental study, six field soils
from Mysuru and Chamarajanagar districts were
selected based on their index properties and clay
mineralogical composition.
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50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
Methodology
In order to understand the soil characteristics, the
following physical tests and index property tests
were conducted on the soil samples which were
oven dried, passing through 425µ, as per BIS
specifications are Free swell ratio test [IS: 2911
(part-3)-1980] [15], Specific gravity test [IS: 2720
(part-3 sec-1)-1980] [16],Grain size analysis [IS:
2720(part-4)-1985] [17], Atterberg limits [IS: 2720
(part-5)-1985] [18], Cone Penetrometer test using
both water and kerosene as pore fluids [IS: 11196
(1985)] [19], Compaction tests-Reduced Standard
Proctor test (RSP)*, Standard Proctor test (SP) [IS:
2720 (part-7)-1980] [20], Reduced Modified
Proctor test (RMP)**, Modified Proctor test[IS:
2720 (part-8)-1983][21]. Table-1 shows
predominant clay mineral present in the soil
Table-1 Soil Vd Vk Vd/Vk Predominant clay
mineral
1 11 10 1.1 KAOLINITE
2 10 09 1.1 KAOLINITE
3 12 10 1.2 KAOLINITE
4 18 13 1.4 MONTMORILLONITE
5 23 13 1.77 MONTMORILLONITE
6 13 10 1.3 KAOLINITE and
MONTMORILLONITE
* RSP energy is 60% of SP energy.
** RMP energy is 60% of MP energy. Where
Vd = Sediment volume of soil in distilled
water.
Vk = Sediment volume of soil in kerosene.
Table-2 shows physical properties of the soils
Table-2 Soil SOIL
1
SOIL2 SOIL
3
SOIL
4
SOIL
5
SOIL
6
Specific
gravity,G
2.63 2.67 2.60 2.63 2.61 2.72
Grain size
distribution
(%) clay
50
60
50
40
25
45
silt 20 15 22 20 40 22
sand 30 25 18 40 35 33
Atterberg
limits(%)
WL
35
30
31
55
61
32
WP 19 14 17 20 28 20
PI 16 16 14 35 33 12
WS 7 4 3.1 8.4 11 11.4
IS
classification
CL CL CL CH CH CL
About 3kg of soil passing 425 µm is mixed with
different water contents thoroughly and kept inside
a separate polythene covers. The samples were let
to achieve the equilibrium moisture for five to ten
days. Compaction tests RSP, SP, RMP & MP were
done using standard Proctor mould. For each of the
soils, minimum of six trials are done to plot
compaction curves.
Figure 1 through 6 shows compaction curves for
the soils under varying compaction energy levels
Fig-1
Fig-2
1.21.31.41.51.61.71.81.9
22.1
0 10 20 30
Dry
den
sity
(g/
cc)
Water content (%)
RSP
SP
RMP
MP
ZAV LINE (G=2.63)
1.3
1.5
1.7
1.9
2.1
2.3
0 5 10 15 20 25
Dry
den
sity
(g/
cc)
Water content (%)
RSP
SP
RMP
MP
ZAV LINE (G=2.67)
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50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
Fig-3
Fig-4
Fig-5
Fig-6
Table-3 shows the values of optimum moisture
content (OMC) and maximum dry density (MDD)
for the soils with varying compaction energy
levels.
Table-3 Soil OMC
( SP)
γdmax
(SP)
OMC
(RSP)
γ(RSP) OMC(M
P)
γ(MP) OMC(R
MP)
γ(RMP)
Soil
1
17.1 16.7 19.1 16.4 13.4 18.6 13.8 18.1
Soil
2
16 16.4 17 16.1 14.4 16.8 14.7 16.8
Soil
3
13.5 18.5 14.2 18.2 10.2 19.8 10.7 19.3
Soil
4
25.2 14.7 28 14 19.2 16 20 15
Soil
5
18.2 16.3 19 15.7 16.2 17.4 16.6 17.1
Soil
6
16.2 17.5 18.2 17.4 14.6 18.6 15.8 17.8
CBR tests are carried out on compacted soils as per
IS:2720 (Part 16;1987)[22].
Figures 7 to 12 shows load-penetration curves
obtained for compacted soils for varying
percentages of RBI Grade 81 with 20% fly ash.
Fig-7
Fig-8
1.4
1.5
1.6
1.7
1.8
1.9
2
0 10 20 30
Dry
den
sity
(g/
cc)
Water content (%)
RSP
SP
RMP
MP
ZAV LINE (G=2.60)
1.3
1.4
1.5
1.6
1.7
1.8
1.9
0 5 10 15 20 25 30
Dry
den
sity
(g/
cc)
Water content (%)
RSP
SP
RMP
MP
ZAV LINE (G=2.63)
1.2
1.3
1.4
1.5
1.6
1.7
0 10 20 30 40
Dry
den
sity
(g/
cc)
Water content (%)
RSP
SP
RMP
MP
ZAV LINE (G=2.61)
1.4
1.5
1.6
1.7
1.8
1.9
2
0 5 10 15 20 25
Dry
den
sity
(g/
cc)
Water content (%)
RSP
SP
RMP
MP
ZAV LINE (G=2.72)
0
100
200
300
400
500
600
700
0 2 4 6 8
Load
(kg
)
Penetartion (mm)
PENETRATION CURVE FOR SOIL 1
0%
2%
4%
6%
0
50
100
150
200
250
300
0 2 4 6 8
Load
(kg
)
Penetration (mm)
PENETRATION CURVE FOR SOIL 2
0%
2%
4%
6%
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50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
Fig-9
Fig-10
Fig-11
Fig-12
From these figures, it can be observed that CBR
values for soils obtained with 20% fly ash and 4%
RBI Grade 81 admixture is found to be optimum, in
relative comparison to soils without admixture.
Table-4 shows the values of CBR for soils having
different percentage of RBI Grade 81 with 20% fly
ash.
Table-4
Soil
No
Plain
soil
20%fly
ash+2%
RBI
20%fly
ash+4%
RBI
20%fly
ash+6%
RBI
1 1.1 16 18 17
2 1.34 16.7 31.7 16.9
3 1.14 19 30.7 14.9
4 5.1 7.6 12.6 21
5 1.8 9.8 36.5 31
6 7.4 17.4 16 10
Fig-13 shows the variation of CBR values for soils
having different clay mineralogy having 20% fly
ash and varying percentage of RBI Grade 81 with
Liquid limit of soils.
Fig-13
Fig-14shows the variation of CBR values for soils
having different clay mineralogy having 20% fly
ash and varying percentage of RBI Grade 81 with
Plastic limit of soils.
0
100
200
300
400
500
600
700
0 2 4 6 8
Load
(kg
)
Penetration (mm)
PENETRATION CURVE FOR SOIL 3
0%
2%
4%
6%
0
100
200
300
400
0 2 4 6 8
Load
(kg
)
Penetration (mm)
PENETRATION CURVE FOR SOIL 4
0%
2%
4%
6%
0
200
400
600
800
1000
0 2 4 6 8
Load
(kg
)
Penetration (mm)
PENETRATION CURVE FOR SOIL 5
0%
2%
4%
6%
0
100
200
300
400
500
600
700
0 2 4 6 8
Load
(kg
)
Penetration (mm)
PENETRATION CURVE FOR SOIL 6
0%
2%
4%
6%
0
5
10
15
20
25
0 20 40 60 80
(CB
R)%
WL (%)
VARIATION OF CBR WITH LIQUID LIMIT
0%
2%
4%
6%
![Page 7: CORRELATION OF INDEX PROPERTIES WITH THE CBR VALUES OF SOILS WITH AND WITHOUT ADMIXTURESigs/ldh/files/igc 2015 pune/THEME 10... · 2017. 5. 14. · the plain soil could be better](https://reader035.vdocuments.us/reader035/viewer/2022071409/6102629ff2ada04e6b567c33/html5/thumbnails/7.jpg)
50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
Fig-14
Fig-15 shows the variation of CBR values for soils
having different clay mineralogy having 20% fly
ash and varying percentage of RBI Grade 81 with
Plasticity index of soils.
Fig-15
Table-5 shows the equations with regression
coefficient for CBR values with index properties of
soils with and without admixture.
Table-5
From the figures 13 to 15, it can be observed that
CBR values can be better correlated with plastic
limit in relative comparison to liquid limit and
plasticity index of the soils, without admixture
and with 4% RBI Grade 81 admixture and 20%
fly ash.
Figure 16 to 19 shows the relationship between
the CBR values and OMC of soils obtained with
different compaction energy levels.
Fig-16
Fig-17
0
5
10
15
20
25
0 10 20 30 40
CB
R (
%)
WP (%)
VARIATION OF CBR WITH PLASTIC LIMIT
0%
2%
4%
6%
0
5
10
15
20
25
0 20 40 60 80
CB
R (
%)
PI (%)
VARIATION OF CBR WITH PLASTICITY INDEX
0%
2%
4%
6%
0
5
10
15
20
25
0 10 20 30
CB
R (
%)
OMC-RSP (%)
VARIATION OF CBR WITH OMC(RSP)
0%
2%
4%
6%
0
5
10
15
20
25
0 10 20 30 40
CB
R (
%)
OMC-SP (%)
VARIATION OF CBR WITH OMC(SP)
0%
2%
4%
6%
Relation
ship
between
index
properti
es and
compact
ion
characte
ristics of
soils
with
CBR
soils
0%
2%
4%
6%
Equation
(y)
Regress
ion
Co-
efficien
t
Equation
(y)
Regress
ion
Co-
efficient
Equation
(y)
Regress
ion
Co-
efficien
t
Equation
(y)
Regr
essio
n
Co-
effici
ent
WL vs
CBR
0.094x –
1.916
0.81 -0.063x +
18.65
0.35 0.037x +
16.54
0.30 0.166x +
14.84
0.76
WP vs
CBR
0.302x –
3.882
0.93 -0.084x +
19.29
0.46 -0.175x +
20.69
0.76 0.057x +
16.03
0.32
PI vs
CBR
0.049x +
19.06
0.83 -0.045x +
19.16
0.63 -0.049x +
19.22
0.710 -0.049x +
19.22
0.71
![Page 8: CORRELATION OF INDEX PROPERTIES WITH THE CBR VALUES OF SOILS WITH AND WITHOUT ADMIXTURESigs/ldh/files/igc 2015 pune/THEME 10... · 2017. 5. 14. · the plain soil could be better](https://reader035.vdocuments.us/reader035/viewer/2022071409/6102629ff2ada04e6b567c33/html5/thumbnails/8.jpg)
50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
Fig-18
Fig-19
Table-6 shows the equations with regression
coefficient for CBR values with OMC of soils
obtained from varying energy levels.
Table-6 Relationship
between
index
properties
and
compaction
characteristi
cs of soils
with CBR
soils
0% 2% 4% 6%
Equatio
n (y)
Regressio
n
Co-
efficient
Equatio
n (y)
Regressio
n
Co-
efficient
Equatio
n (y)
Regressio
n
Co-
efficient
Equatio
n (y)
Regressio
n
Co-
efficient
OMC (RSP)
vs CBR
0.308x
– 3.912
0.94
0.757x
+4.665
0.88
0.825x
+ 3.585
0.91
1.006x
+ 0.788
0.96
OMC (SP)
vs CBR
0.367x
– 4.520
0.95
0.080x
+ 19.21
0.61
-0.057x
+ 18.35
0.63
-0.080x
+ 19.21
0.61
OMC
(RMP) vs
CBR
0.423x
– 4.318
0.85
0.859x
+ 2.053
0.98
0.906x
+ 1.257
0.99
0.906x
+ 1.257
0.99
OMC (MP)
vs CBR
0.424x
– 4.134
0.83
0.709x
+ 5.795
0.89
0.820x
+ 4.076
0.94
0.820x
+ 4.076
0.94
From the figures 16 to 19 it can be observed that,
the CBR values can be better correlated with OMC
irrespective of clay mineralogy of soils and
compactive energy levels, with coefficients ranging
from 0.88 to 0.96 for RSP, 0.61 to 0.95 for SP,
0.86 to 0.99 for RMP and 0.83 to 0.94 for MP.
Figures 20 to 23 show the relationship between the
CBR values and MDD of soils obtained from
different compaction energy levels.
Fig -20
Fig-21
0
5
10
15
20
25
0 5 10 15 20 25
CB
R (
%)
OMC-RMP (%)
VARIATION OF CBR WITH OMC(RMP)
0%
2%
4%
6%
0
5
10
15
20
25
0 5 10 15 20 25
CB
R (
%)
OMC-MP (%)
VARIATION OF CBR WITH OMC (MP)
0%
2%
4%
6%0
5
10
15
20
25
0 10 20 30
CB
R (
%)
γ-RSP (g/cc)
VARIATION OF CBR WITH γRSP
0%
2%
4%
6%
0
5
10
15
20
25
0 5 10 15 20 25 30
CB
R (
%)
γ-SP (g/cc)
VARIATION OF CBR WITH γSP
0%
2%
4%
6%
![Page 9: CORRELATION OF INDEX PROPERTIES WITH THE CBR VALUES OF SOILS WITH AND WITHOUT ADMIXTURESigs/ldh/files/igc 2015 pune/THEME 10... · 2017. 5. 14. · the plain soil could be better](https://reader035.vdocuments.us/reader035/viewer/2022071409/6102629ff2ada04e6b567c33/html5/thumbnails/9.jpg)
50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
Fig-22
Fig-23
Table-7 shows the equations with regression
coefficient for CBR values with MDD of soils
obtained from varying energy levels.
Table-7
It can also observed that CBR values can also be
correlated with MDD of soils having different clay
mineralogy and compactive energy levels with
regression coefficients ranging from 0.77 to 0.83
for RSP, 0.80 to 0.85 for SP, 0.78 to 0.92 for RMP
and 0.3 to 0.95 for MP respectively.
Figures 24 to 29 show variations of CBR for soils
having different percentages of RBI Grade 81
admixtures.
Fig-24
Fig-25
0
5
10
15
20
25
0 5 10 15 20 25
CB
R (
%)
γ- RMP(g/cc)
VARIATION OF CBR WITH γRMP
0%
2%
4%
6%
0
5
10
15
20
25
0 5 10 15 20 25
CB
R (
%)
γ-MP (g/cc)
VARIATION OF CBR WITH γMP
0%
2%
4%
6%
y = -0.993x2 + 8.447x + 1.595R = 0.99
0
5
10
15
20
25
0 2 4 6 8
CB
R(%
)
RBI(%)
CBR v/s %RBI FOR SOIL 1
y = -1.883x2 + 14.38x - 0.136R = 0.95
-5
0
5
10
15
20
25
30
35
0 2 4 6 8
CB
R(%
)
RBI(%)
CBR v/s %RBI FOR SOIL 2
Relationshi
p between
index
properties
and
compaction
characterist
ics of soils
with CBR
soils
0% 2% 4% 6%
Equati
on (y)
Regressi
on
Co-
efficient
Equati
on (y)
Regressi
on
Co-
efficient
Equati
on (y)
Regressi
on
Co-
efficient
Equati
on (y)
Regressi
on
Co-
efficient
γ (RSP) vs
CBR
-0.909x
+ 17.23
0.831
-0.171x
+ 20.56
0.765
-0.277x
+ 21.83
0.833
-0.222x
+ 21.81
0.813
γ (SP) vs
CBR
-1.010x
+ 18.79
0.803 -0.274x
+ 22.39
0.847 -0.266
+ 22.39
0.827 -0.212x
+21.02
0.822
γ (RMP) vs
CBR
-0.940x
+ 18.44
0.775 -0.379x
+ 23.25
0.924 -0.379x
+ 23.25
0.924 -0.349x
+ 22.74
0.843
γ (MP) vs
CBR
-0.815x
+ 16.56
0.716 -0.403x
+ 23.27
0.948 -0.403x
+ 23.37
0.298 -0.388x
+ 23.12
0.891
![Page 10: CORRELATION OF INDEX PROPERTIES WITH THE CBR VALUES OF SOILS WITH AND WITHOUT ADMIXTURESigs/ldh/files/igc 2015 pune/THEME 10... · 2017. 5. 14. · the plain soil could be better](https://reader035.vdocuments.us/reader035/viewer/2022071409/6102629ff2ada04e6b567c33/html5/thumbnails/10.jpg)
50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
Fig-26
Fig-27
Fig-28
Fig-29
From the figures 24 to 29 it can be concluded that,
CBR values for soils having different clay
mineralogy with varying energy levels can be
better correlated with percentage of RBI Grade 81
to be mixed with soils with higher regression range
from 0.92 to 0.99.
CONCLUSIONS
From the present experimental study, the following
conclusions can be made
Plastic limit of soils can be better correlated
with CBR of soils with and without
admixture, irrespective of clay mineralogy in
relative comparison to liquid limit and
plasticity index.
CBR of plain soils and soils having 4% RBI
Grade 81 and 20% fly ash admixture can be
better correlated with plastic limit of soils, in
relative comparison to liquid limit and
plasticity index of the soils.
Compaction characteristics, OMC and MDD
can be correlated effectively with soils
having 20% fly ash and varying percentages
of RBI Grade 81 (2% to 6%) irrespective of
compactive energy levels and clay
mineralogy of soils.
y = -2.041x2 + 15.24x + 0.023R= 0.97
0
5
10
15
20
25
30
35
0 2 4 6 8
CB
R(%
)
RBI(%)
CBR v/s %RBI FOR SOIL 3
y = 0.373x2 + 0.393x + 5.152R = 0.99
0
5
10
15
20
25
0 2 4 6 8
CB
R(%
)
RBI(%)
CBR v/s %RBI FOR SOIL 4
y = -0.838x2 + 10.75x - 0.738R = 0.92
-5
0
5
10
15
20
25
30
35
40
0 2 4 6 8
CB
R(%
)
RBI(%)
CBR v/s %RBI FOR SOIL 5
y = -1.002x2 + 6.341x + 7.702R = 0.98
0
5
10
15
20
0 2 4 6 8
CB
R(%
)
RBI(%)
CBR v/s %RBI FOR SOIL 6
![Page 11: CORRELATION OF INDEX PROPERTIES WITH THE CBR VALUES OF SOILS WITH AND WITHOUT ADMIXTURESigs/ldh/files/igc 2015 pune/THEME 10... · 2017. 5. 14. · the plain soil could be better](https://reader035.vdocuments.us/reader035/viewer/2022071409/6102629ff2ada04e6b567c33/html5/thumbnails/11.jpg)
50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
REFERENCES
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Soils and Foundations, Vol.44, No.5, pp 27-36.
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grade soil and base course of flexible
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12. Haricharan et al (2013), “Laboratory
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![Page 12: CORRELATION OF INDEX PROPERTIES WITH THE CBR VALUES OF SOILS WITH AND WITHOUT ADMIXTURESigs/ldh/files/igc 2015 pune/THEME 10... · 2017. 5. 14. · the plain soil could be better](https://reader035.vdocuments.us/reader035/viewer/2022071409/6102629ff2ada04e6b567c33/html5/thumbnails/12.jpg)
50
th
IGC
50th
INDIAN GEOTECHNICAL CONFERENCE
17th
– 19th
DECEMBER 2015, Pune, Maharashtra, India
Venue: College of Engineering (Estd. 1854), Pune, India
water content-density relation using light
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