IRJET- Experimental Approach for Stabilizing Sub Grades on Expansive Soil

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 06 Issue: 05 | May 2019 www.irjet.net p-ISSN: 2395-0072
© 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 1092
Experimental Approach for Stabilizing Sub Grades on Expansive Soil
Prashast Dheer1, Satya Veer Singh2
1M.Tech Student, Department of Civil Engineering, Rama University, (India)
2Assistant Professor, Department of Civil Engineering, Rama University, (India)
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Abstract:- The cyclic heave and settlement of expansive
soils is one of the major reasons for damages to the roads and
highways in considerable part ofcountry like India. Expansive
clays usually have low bearing capacity, high shrinkage &
swelling properties. Due to tendency to swell, it causes large
uplift pressures and upheaval of structures built on them.
Replacing expansive soil in most of the cases is notpractically
possible, hence stabilization measures must be undertakento
treat them. This paper presentsanexperimental investigation
for treatment of expansive soil with lime to improve its
bearing capacity and minimize swelling. Expansive soil
treated with lime with varying quantity of 0%, 2%, 4%, 6%,
8% & 10% w.r.t dry weight of soil taken was studied.
California Bearing Ratio & free swell index for each soil
composite were evaluated. It was found that with addition of
lime, CBR of soil composite increased and swelling declined.
The optimum content of lime found to be 10% with most
significant improvement in strengthandreduction inswelling
properties of the soil. Based on the results, it is concluded that
lime admixture can be considered as a suitable option for the
stabilization of expansive subgrades.
Keywords: Lime, Expansive Soil, Shrinkage & Swelling,
CBR, Compaction characteristics, Subgrades.
Abbreviations: CBR- California Bearing Ratio, FSI- Free
Swell Index
I. INTRODUCTION
Dealing with soft subgrade or unsuitable soil is one of the
major problems for civil engineering projects. This situation
may arise in roadways or highway construction. Since there
is reduction in sites for construction development, it is
crucial to find ways for soil improvement techniques to
respond to the demands. Such soils need addition of some
strengthening elements to decrease the compressibility and
to enhance the strength of the subgrade so thatcosteffective
construction of works is possible. One of the reliable
stabilizing material is lime. It is a calcium-containing
inorganic mineral in which oxides and hydroxides
predominate. Calcium hydroxide (traditionallycalledslaked
lime) is an inorganic compound with the chemical formula
Ca (OH) 2. It is a colorless crystal or white powder and is
obtained when lime is mixed or slaked with water. Calcium
hydroxide is used in many applications, including food
preparation. Limewater is the common name fora saturated
solution of calcium hydroxide.
Many research works have been done in past decade on
introduction of lime in expansive soil. Muzahim et al., 2012
studied improvements of geotechnical properties of
expansive soil behavior due to the lime-clay reactions,
mainly a pozzolanic reaction, using microscopic analysis.
Guillaume et al., 2012 examined the impact of a wetting and
drying path on the swelling/shrinkage of a compacted lime-
treated expansive clayey soil both at the macro- and micro-
scales. The study showed that lime treatment had a limited
effect on lime-treated compacted soil shrinkage whilst
preventing swelling. T. Thyagaraj et al., 2012 attempted to
study the precipitation of lime in soil by successivemixingof
CaCl2 and NaOH solutions with the expansive soil in two
different sequences. Experimental results indicated that in
situ precipitation of lime in soil by sequential mixingofCaCl2
and NaOH solutions with expansive soil developed strong
lime-modificationandsoil-limepozzolanicreactions.Results
also showed that the sequential mixingof expansivesoil with
CaCl2 solution followed by NaOH solution is more effective
than mixing expansive soil with NaOH solution followed by
CaCl2 solution. Sireesh etal.,2013initiatedtounderstandthe
behavioral mechanisms of lime and cement stabilized
organic soils. Eight natural expansive soils bearing different
organic contents (varying between 2 and 6%) were selected
for the investigation. Further research work carried out by
M. R. Asgari et al., 2013 which showed that addition of a few
percentages of lime results in increase of unconfined
compressive strength also According to the results of
compaction tests, the effect of lime is more than effect of
cement on optimum water content and maximum dry unit
weight so that the changes of optimum water content and
maximum dry unit weight due to addition of cement content
do not have a general tendency, whereas addition of lime
decreases maximum dry unit weight and also increases
optimum water content. Based on the CBR and compressive
strength tests, Amir Modarres et al., 2015 showed that the
addition of coal waste powder and its ash to some extent
enhances the soil bearing capacity. However, the
combination of these additives with lime results in
considerably higher compressive strength and CBR
especially in saturated conditions. Argawetal.,2016studied
stabilization of expansive soil (C) with steel slag (SS), rice
husk ash (RHA), and quick lime (L). The geotechnical
properties, shearing strength characteristics, and dynamic
properties of stabilized soil have beenstudied.Theoptimum
mix is found to be in the proportion of 65C + 20SS + 5L +
10RHA. The stiffness of stabilized soil increases to 58–78%
as compared to clay soil. Moghal et al., 2016 studied
stabilization of expansive soil (C) with steel slag (SS), rice

husk ash (RHA), and quick lime (L). The geotechnical
properties, shearing strength characteristics, and dynamic
properties of stabilized soil have beenstudied.Theoptimum
mix is found to be in the proportion of 65C + 20SS + 5L +
10RHA. The stiffness of stabilized soil increases to 58–78%
as compared to clay soil. Moghal et al., 2016 studied two
stiffness of stabilized soil increases to 58–78% as compared
to clay soil. Moghal et al., 2016 studied two different types of
synthetic fibers, Fiber Mesh and Fiber Cast, as a stabilization
alternative for expansive soils in the presence of lime.
California bearing ratio (CBR) is chosen as a performance
indicator as it is a good pointer towards pavement
effectiveness. The deterministic approach showed that the
improvement in CBR increased with higher fiber contents
and longer lengths and the effect was prominent when lime
was used as a stabilizer. Liet Chi Dang et al., 2017 presented
a paper on experimental investigation on the enhancement
of swelling behavior and soil water characteristic curve
(SWCC) of bagasse fiber and lime stabilized expansive soil.
The results revealed that lime-bagasse fiber treatment of
expansive clay has a significant effect on swelling behavior
and SWCC response of treated soils. G. Sridevi et al.2019
performed experiments onRedmud stabilizedwith4%lime
and lime-stabilized red mud is added to the expansivesoil in
different percentages varying from 10 to 50% in increments
of 10%. Tests are also conducted on soils stabilized with
lime-stabilized red mud and fly ash, adding them in equal
quantities along with 4% lime. The results show that red
mud as well as red mud–fly ash improves the geotechnical
properties of the soil.
2. MATERIALS AND METHODS
2.1 Materials
The materials used in the present work are black cotton soil
and hydraulic lime.
2.1.1 Black Cotton Soil
Soil sample received was dried in sun. The clods were
broken with wooden mallet. Organic matters like grass &
roots and matters other than soil were removed. The
geotechnical properties of selected soil are mentioned in
table 1.
Table. 1 Geotechnical properties of selected soil
S.NO. CHARACTERSTICS VALUE
1 Liquid Limit, (%) 53
2 Plastic Limit, (%) 24
3 Plasticity Index, (%) 29
4 Classification (ISSCS) CH
5 Maximum Dry Density, (g/cc) 1.7
6
Optimum Moisture Content,
(%)
17
7 California Bearing Ratio, (%) 2.48
8 Free Swell Index 45
2.1.2 Hydraulic Lime
Lime used in this study is hydraulic lime. The term
"hydraulic lime" covers materials that vary in properties
such as setting times and strength development, buttheyare
never to be thought of or used as a cement substitute.
Hydraulic lime are characterized by good workability, low
shrinkage, salt and frost resistance, adequate compressive
and good flexural strength. The properties of hydraulic lime
are influenced by the existence of certain impurities and by
the methods of burning and slaking. If clays orothersuitably
reactive forms of silicates and aluminates are present in the
original limestone the resulting lime will have hydraulic
properties, i.e. it will have some ability to set in wet
conditions.
2.2 Methods
2.2.1 Sample Preparation
Soil composites were prepared by mixing soil with 2%, 4%,
6%, 8% & 10% of lime by weight of dry soil. Mixing was done
manually with proper care to make a uniform mix.
2.2.2 Tests
Laboratory tests have been carried out as per IS 2720tofind
out the type and properties of virgin soil. For each soil
composites experiments were performed to determine free
swell index and CBR.
3. RESULTS AND DISCUSSIONS
3.1 Results
The results obtained from various laboratory investigations
are summarized in table 2.
Table. 2 Summary of test results
S.NO % LIME ADDED FSI CBR
1 0 45 2.48
2 2 36 4.5
3 4 29 6.1
4 6 21 7.9
5 8 16 9.2
6 10 12 9.1

3.2 Discussions
3.2.1 Variation of FSI
Fig. 1 FSI vs %lime
Fig 1 shows that addition of lime reduced swelling tendency
of soil. The change is following decreasing trendthroughout.
3.2.2 Variation of CBR
Fig. 2 CBR vs %lime
Figure 2 shows variation of CBR with varying percentages of
lime in soil composite. Figure illustratesthatwithaddition of
lime, CBR of soil increased linearly. Maximum increase in
CBR is observed at 8% lime content by dry weight of soil.
However beyond 8% mix, the value of CBR did not show any
considerable change.
4. CONCLUSIONS
1. Inclusion of hydraulic lime raised CBR of the soil. The
increase is directly proportional to lime content to a
maximum of 8% beyond which change is not significant.
2. Addition of lime also reduced swelling of soil. There is
constant decrease in swelling as the content of lime is
increased. Swelling reduced from FSI-45 to FSI-12 for
10% mix.
3. Based on results it may be concluded that addition of
10% lime can raise CBR and reduce swelling of weak
expansive subgrades and hence is suitable as an additive
for road stabilization.
References
[1] Muzahim et al., Microstructure and geotechnical
properties of lime-treated expansive clayey soil,
Elsevier, Engineering Geology 139-140 (2012) 17–27
[2] Guillaume et al., Multi-scale analysis of the swelling
and shrinkage of a lime-treated expansive clayey soil,
Elsevier, Applied Clay Science 61 (2012) 44–51
[3] Thyagaraj et al, Laboratory Studies on Stabilization
of an Expansive Soil by Lime Precipitation Technique,
(ASCE), J. Mater. Civ. Eng., 2012, 24(8): 1067-1075
[4] Sireesh et al, Swell-shrink and strength behaviors of
lime and cement stabilized and expansiveorganicclays,
(Elsevier), Applied Clay Science 85 (2013) 39–45

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