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International Journal of Engineering and Technology Volume 6 No.6, June, 2016
ISSN: 2049-3444 © 2016 – IJET Publications UK. All rights reserved. 182
Stabilization of A-2-7(0) Laterite Soil and Strength Characteristics Using
Three Selected Cements Individually
I. Akiije Department of Civil and Environmental Engineering, University of Lagos, Akoka, Yaba, Lagos, Nigeria
ABSTRACT
This study investigated the stabilization of A-2-7(0) laterite soil and strength characteristics using grades 42.5N, 42.5R and 32.5N
cements individually in such a manner as to improve the performance of the soil for highway pavement. In the process specimens
prepared from laterite soil sample from Ondo town environs borrow pit in Nigeria for highway construction were subjected to
laboratory tests. The values obtained from the laboratory tests for bulk density, dry density, specific gravity, wet sieve analysis, void
ratio, porosity, degree of saturation, liquid limit, plastic limit and plasticity index of the laterite soil samples tested confirmed that it
is a granular material of clayey gravel and sand. This group classification result shows that it is A-2-7(0) laterite soil that is good
only as subgrade highway material. In order to improve and determine the performance of the soil at optimal level as a basecourse
highway pavement material, it was subjected to stabilization comparison by using readily available cements of grades 42.5N, 42.5R
and 32.5N. Stabilization of each cement type with A-2-7(0) laterite soil at cement content of 4%, 6%, 8%, 10%, 12% and 14% was
carried out in order to determine the variations of OMC, MDD, UCS and CBR at maximum. Significantly, graphical presentation of
the results of the A-2-7(0) laterite soil using the three selected cements separately shows that at maximum of 14% and optimal use of
8% cement content respectively of stabilization, it is the grade 32.5N cement of lower rating that has the highest values of UCS and
CBR correspondingly. Soaked CBR values resulted from using grades 42.5N, 42.5R and 32.5N cements separately of the stabilized
A-2-7(0) laterite soil are strongly related because the determination correlation R value = 0.9997 indicating that grade 42.5N cement
should only be used in the absence of grade 32.5N cement and before the use of grade 42.5R cement.
Keywords: Borrow Pit, Percentages, Graphical, Economical, Subbase, Basecourse, Correlation
1. INTRODUCTION
Laterite soil at a particular location for highway pavement is
usually not of the same strength at other locations along a given
road particularly for a lengthy one. Long haulage of laterite soil
may as well not be economical and so the nearby material may
be stabilized and economically used for subbase or basecourse.
Subgrade or highway foundation soil California Bearing Ratio
(CBR) value may not be up to 5% and in such situation it has to
be stabilized in place by making it suitable subbase before the
placement of basecourse material in the construction of a road.
Akinwumi (2014) reported that in the tropical regions, laterite
soils occupy about 23 percent of the land surface and selecting
them for use as highway materials can be economically viable.
He further reported that some of the lateritic soils are unsuitable
for use as road construction materials because their properties
do not comply with existing standard requirements. The
reasons given by him are that some of laterite soils exhibit high
plasticity, poor workability, low strength, high permeability,
tendency to retain moisture and high natural moisture content.
Mustapha (2005) claimed that there are instances where laterite
soil containing a large amount of clay minerals with weak
strength and instability to sustain traffic load especially in the
presence of moisture are common in many tropical regions and
sourcing for alternative soil may prove uneconomical and
hence it may be better to improve the available soil to meet the
desired strength. Ali (2012) claimed that soil stabilization is a
process to improve the physical and engineering properties of
soil to obtain some predetermined targets.
Kadyali and Lal (2008) and Akiije (2015) claimed that
stabilization of soils could be achieved using aggregate,
bitumen, cement, salt, lime, sodium silicate, calcium chloride
and resinous materials. The most economical stabilization
methodology challenge the engineer is facing at a particular
situation depends upon the choosing and using readily available
stabilizer at a particular time whilst strength developed for the
design and construction of the highway pavement (Osinubi and
Amadi, 2010); (Akinwumi, 2014) and (Salahudeen and Akiije,
2014). Soil stabilization using chemical compounds such as
cement and lime increases soil strength parameters, enhances
capacity and decreases soil settlement at low cost particularly in
the projects that require a high volume of soil improvement (Ou
et al., 2011) and (Marto et al.,2013). However, (Liu, et al.,
2011) claimed that analysis performed on traditional chemical
stabilizers such as lime and cement are more common when
compared with nontraditional researches that are done by
mechanical stabilization. Latifi et al (2013) claimed that
traditional stabilizers include cement, lime, fly ash, and
bituminous materials, while nontraditional stabilizers consist of
various combinations such as enzymes, liquid polymers, resins,
acids, silicates, ions, and lignin derivatives.
Akinwumi et al., (2012) claimed that the coarser the grain of a
soil is the less water it requires to reach the optimum moisture
content. Also, Wright and Dixon (2003) and (Garber and Hoel,
2010) claimed that as the compactive effort on soil increases so
is the maximum density and whilst the moist content also
decreases. Cement stabilization of soils usually involves the
International Journal of Engineering and Technology (IJET) – Volume 6 No. 6, June, 2016
ISSN: 2049-3444 © 2016 – IJET Publications UK. All rights reserved. 183
addition of 5% to 14% Portland cement by volume of the
compacted mixture to the soil being stabilized which could be
naturally occurring soil or artificially created soils or soil-
aggregate mixtures Wright and Dixon (2003) and (Garber and
Hoel, 2010). Kadyali and Lal (2008) claimed that the most
popular design criterion for soil-cement is in terms of
unconfined compressive strength after 7 days moist curing
having the rage value of 1.7MN/m 2 to 2.76MN/m 2 using
cylindrical specimen of ratio 2:1 height to diameter. The
desirable range for CBR value for subbase layer is 20% to 30%
and desirable range for basecourse is 80% to 100% according
to Kadyali and Lal (2008).
According to BS EN 197-1 (2011) cement is a hydraulic
binder, i.e. a finely ground inorganic material which, when
mixed with water, forms a paste which sets and hardens by
means of hydration reactions and processes and which, after
hardening, retains its strength and stability even under water.
Cement grade 42.5N indicates standard normal early strength at
28days by a prism of cement. Cement grade 42.5R indicates
standard rapid higher early strength at 28days by a prism of
cement. Cement grade 32.5N indicates standard normal
strength at 28days by a prism of cement.
The aim of this study is to compare and contrast strength
characteristics of the stabilization of A-2-7(0) laterite soil using
three selected cements that are of grades 42.5N, 42.5R and
32.5N individually. Specifically the objectives are:
1. To carry out laboratory tests in order to define basic and
engineering properties of the laterite soil as well as when
stabilized with the three cements individually.
2. To identify the best stabilizer when each one of them is
used individually to stabilize A-2-7(0) laterite soil that will
yield long-lasting subbase or basecourse material for
highway pavement regarding strength.
3. To establish among the three stabilizers the one that will
provide a cheaper stabilized subbase/basecourse material
during the design and construction of the highway
pavement.
The main scope of work in this study therefore includes
obtaining laterite soil material from a borrow pit meant for the
preparation of stabilized subbase/basecourse of not far distance
road and subjecting it to physical and chemical laboratory tests.
The significance of this study is in ensuring the reliability that
the chosen cement among the three stabilizers is most
economical and will not quickly subject highway pavement
surface to premature failure.
2. MATERIALS AND METHODOLOGY The laterite soil sample used in this study was obtained from a
borrow pit in use for highway pavement construction in Ondo
town and environs in Ondo State of Nigeria. Tests on the
collected laterite soil sample were carried out in the laboratory
of the Department of Civil and Environmental Engineering,
Faculty of Engineering, University of Lagos, Nigeria. The tests
were carried out according to the American Association of
State and Transportation Officials (AASHTO, 2007).
The sample was air dried in the laboratory to take advantage of
the aggregating potentials of lateritic soils upon exposure to air
as claimed by Omotosho and Eze-Uzomaka (2008). Tests were
carried out and basic and engineering properties of the selected
laterite soil in the laboratory were carried out in order to
determine the values of bulk density, dry density, specific
gravity, wet sieve analysis, void ratio, porosity, saturation
degree, liquid limit, plastic limit and plasticity index.
Three types of cements of grades 42.5N, 42.5R and 32.5N were
purchased in 50 kg bag each from the market for use in the
laboratory for stabilization tests. Strength tests were carried out
on the air dried laterite soil stabilized with cements of grades
42.5N, 42.5R and 32.5N at cement content of 4%, 6%, 8%,
10%, 12% and 14% separately. For the strength tests, optimum
moisture content (OMC) was first determined and then
followed by maximum dry density (MDD). Unsoaked and
soaked CBR tests were also carried out as well as uncured and
cured unconfined compressive strength tests. Relationships
among the soaked and unsoaked CBR values obtained from the
three types of cements separately used for the stabilization of
A-2-7(0) laterite soil were compared for determination
correlation R values.
3. ANALYSIS OF RESULTS AND
DISCUSSIONS
Figure 1 shows that 35% maximum of the total laterite soil
sample passing through sieve size 0.075 mm by the way of wet
sieve analysis employed indicated that it is a granular material.
Table 1 expresses the basic and engineering properties of the
laterite soil sample material tested in the laboratory based upon
the methodologies defined by AASHTO (2007) soil
classification system. The laboratory determination of the
particle-size distribution of the laterite soil sample shows that it
is a granular material and falls into group classification of A-2-
7(0). The group symbol A-2-7 shows that the laterite soil is of
clayey gravel and sand while the group index 0 shows that it is
a good material for subgrade. The values obtained from the
laboratory tests for bulk density, dry density, specific gravity,
void ratio, porosity, degree of saturation, liquid limit, plastic
limit and plasticity index of the laterite soil samples tested
confirmed that the material is clayey gravel and sand.
International Journal of Engineering and Technology (IJET) – Volume 6 No. 6, June, 2016
ISSN: 2049-3444 © 2016 – IJET Publications UK. All rights reserved. 184
Figure 1: Grain size analysis of the A-6(10) natural laterite soil
sample
Table 2 shows the comparison of the strength characteristics of
the A-2-7(0) laterite soil when stabilized with cements of
grades 42.5N, 42.5R and 32.5N at maximum cement content of
14% individually. This Table shows that at maximum cement
content of 14% laterite soil-cement stabilization the use of
grade 32.5N cement proffered the lowest OMC value of 15.4%
as well as the highest MDD of 1.9663/ mMg . In the facet,
specimens stabilized with grade 32.5N cement also have the
highest CBR values of 166.25% and 122.25% for both soaked
and unsoaked samples respectively. A-2-7(0) laterite
specimens stabilized with grade 42.5N cement have slight
higher CBR values of 159.5% and 121% for both soaked and
unsoaked lateritic soil samples over that of grade 42.5R
cement stabilization with values of 156% and 119.25%
respectively. Also in Table 2, similar trends are seen for both
cured and uncured unconfined compressive strengths of
cements of grades 42.5N, 42.5R and 32.5N specimens of A-2-
7(0) soil-cement stabilization. For cured and uncured UCS,
uq values at maximum of 14% A-2-7(0) laterite soil-32.5N
cement specimen stabilization has the highest values 296.443 2/ mkN and 217.391 2/ mkN respectively of the three
cements used. Whilst A-2-7(0) soil-cement stabilization using
grade 42.5N cement cured and uncured UCS u
q values are
272.277 2/ mkN and 207.921 2/ mkN correspondingly,
stabilizing this soil sample with cement of grade 42.5R resulted
in 264.212 2/ mkN and 203.373 2/ mkN respectively. In this
aspect, it is pertinent to note that A-2-7(0) laterite soil with
cured and uncured UCS values of 89.641 2/ mkN and
59.880 2/ mkN respectively, with consistency of medium stiff
has been upgraded to very stiff consistency due to stabilization
process by having u
q values ranging from 203.373 2/ mkN to
296.443 2/ mkN .
Table 1: Basic and Engineering Properties of the selected
laterite soil
Table 2: Results of A-2-7(0) laterite soil strength when
stabilized with grades 42.5N, 42.5R and 32.5N cements
at maximum of 14% separately
Figures 2 to 7 respectively show the variations and
comparisons of unconfined compressive strength and the
International Journal of Engineering and Technology (IJET) – Volume 6 No. 6, June, 2016
ISSN: 2049-3444 © 2016 – IJET Publications UK. All rights reserved. 185
related strain when A-2-7(0) laterite soil samples were
stabilized with cement grades 42.5N, 42.5R and 32.5N at
maximum of 14% separately under uncured and cured
conditions in the laboratory. Figure 2 shows the variation of
uncured UCS with strain of the A-2-7(0) laterite soil stabilized
with cement grade 32.5N increasing at cement content of 0%,
4%, 6%, 8%, 10%, 12%, and 14% with corresponding values of
uq as 59.880 2/ mkN , 74.405 2/ mkN , 139.165 2/ mkN ,
188.867 2/ mkN , 198.413 2/ mkN , 208.748 2/ mkN , and
217.391 2/ mkN . Figure 3 also shows the variation of uncured
UCS with strain of the A-2-7(0) laterite soil stabilized with
cement grade 42.5N increasing at cement content of 0%, 4%,
6%, 8%, 10%, 12%, and 14% with corresponding values of u
q
as 59.880 2/ mkN , 69.8602/ mkN , 124.008 2/ mkN ,
178.218 2/ mkN , 188.492 2/ mkN , 198.413 2/ mkN , and
207.921 2/ mkN . Figure 4 similarly shows the variations of
uncured UCS with strain of the A-2-7(0) laterite soil stabilized
with cement grade 42.5R increasing at cement content of 0%,
4%, 6%, 8%, 10%, 12%, and 14% with corresponding values of
uq as 59.880 2/ mkN , 64.870 2/ mkN , 105.210 2/ mkN ,
159.046 2/ mkN , 178.571 2/ mkN , 185.644 2/ mkN , and
203.373 2/ mkN . On the other hand, Figure 5 displays the
variations of cured UCS with strain of the A-2-7(0) laterite soil
stabilized with cement grade 32.5N increasing at cement
content of 0%, 4%, 6%, 8%, 10%, 12%, and 14% with
corresponding values of u
q as 89.641 2/ mkN ,
114.542 2/ mkN , 149.105 2/ mkN , 208.748 2/ mkN ,
223.658 2/ mkN , 257.937 2/ mkN , and 296.443 2/ mkN .
Likewise, Figure 6 displays the variations of cured UCS with
strain of the A-2-7(0) laterite soil stabilized with cement grade
42.5N increasing at cement content of 0%, 4%, 6%, 8%, 10%,
12%, and 14% with corresponding values of u
q as
89.641 2/ mkN , 99.404 2/ mkN , 140.281 2/ mkN ,
199.601 2/ mkN , 213.718 2/ mkN , 248.509 2/ mkN , and
272.277 2/ mkN . Figure 7 as well displays the variations of
cured UCS with strain of the A-2-7(0) laterite soil stabilized
with cement grade 42.5R increasing at cement content 0%, 4%,
6%, 8%, 10%, 12%, and 14% with corresponding values of u
q
as 89.641 2/ mkN , 94.936 2/ mkN , 138.807 2/ mkN ,
188.680 2/ mkN , 210.779 2/ mkN , 238.509 2/ mkN , and
264.212 2/ mkN .
Figure 2: Variation of uncured UCS to strain of the
A-2-7(0) laterite soil stabilized with grades 32.5N cement
at varying percentages
Figure 3: Variation of uncured UCS to strain of the A-2-7(0)
laterite soil stabilized with grades 42.5N cement at varying
percentages
International Journal of Engineering and Technology (IJET) – Volume 6 No. 6, June, 2016
ISSN: 2049-3444 © 2016 – IJET Publications UK. All rights reserved. 186
Figure 4: Variation of uncured UCS to strain of the
A-2-7(0) laterite soil stabilized with grades 42.5R cement
at varying percentages
Figure 5: Variation of cured UCS to strain of the A-2-7(0) laterite
soil stabilized with grades 32.5N cement at varying percentages
Figure 6: Variation of cured UCS to strain of the
A-2-7(0) laterite soil stabilized with grades 42.5N cement
at varying percentages
Figure 7: Variation of cured UCS to strain of the
A-2-7(0) laterite soil stabilized with grades 42.5R cement
at varying percentages
Figure 8 shows the variation of uncured and cured unconfined
compressive strength with varying cement content of 0%, 4%,
6%, 8%, 10%, 12, and 14% for the A-2-7(0) laterite soil
stabilized with cement grades 42.5N, 42.5R and 32.5N
separately. The A-2-7(0) laterite soil at 0% of cement content
stabilization or natural state uncured and cured is of medium
stiff consistency for the values are 59.880 2/ mkN and
89.641 2/ mkN respectively. Cured UCS at 4% of A-2-7(0)
laterite soil-32.5N cement stabilization is 114.542 2/ mkN with
stiff consistency other cured and uncured specimens u
q values
International Journal of Engineering and Technology (IJET) – Volume 6 No. 6, June, 2016
ISSN: 2049-3444 © 2016 – IJET Publications UK. All rights reserved. 187
are from 64.870 2/ mkN to 99.404 2/ mkN indicating that they
are of medium stiff consistency. Also, cured UCS at 6% of A-
2-7(0) laterite soil-32.5N cement stabilization is
149.105 2/ mkN with very stiff consistency, other cured and
uncured specimens u
q values are from 105.210 2/ mkN to
140.281 2/ mkN indicating that they are of stiff consistency. It
is pertinent to note that the values of cured UCS at 8%, 10%,
12% and 14% of A-2-7(0) laterite soil-32.5N cement
stabilization are 208.748 2/ mkN , 223.658 2/ mkN ,
257.937 2/ mkN and 296.443 2/ mkN indicating that they are of
very stiff consistency. Cured UCS at 10%, 12% and 14% only
of A-2-7(0) laterite soil-42.5N and 42.5R cement stabilization
are of very stiff consistency for having values ranging from
210.779 2/ mkN to 264.212 2/ mkN . Also, the values of
uncured UCS at 12% and 14% of A-2-7(0) laterite soil-32.5N
cement stabilization are 208.748 2/ mkN and
217.391 2/ mkN indicating that they are of very stiff
consistency, whereas uncured UCS at 14% only of A-2-7(0)
laterite soil-42.5N and 42.5R cement stabilization are of very
stiff consistency for having values of 207.921 2/ mkN and
203.373 2/ mkN .
Figure 8: Variation of UCS uncured and cured compressive
strength with varying cement content upon A-2-7(0)
laterite soil stabilization
Figure 9 displays the variation of unsoaked California Bearing
Ratio with varying amount of cement upon A-2-7(0) laterite
soil stabilization with cement grades 42.5N, 42.5R and 32.5N
separately. This figure indicates that the unsoaked California
Bearing Ratio at 0% of A-2-7(0) natural laterite soil is 23.5%.
The value obtained is higher than 11% CBR value which is the
standard recommendation for highway subgrade or foundation.
Also, at 4% of A-2-7(0) laterite soil-42.5N, 42.5R and 32.5N
cements stabilization, the unsoaked CBR values are 34.75%,
32.75% and 40.75% respectively which are higher than 30%
standard recommendation for highway subbase. Figure 9 shows
the unsoaked CBR values at 6%, 7%, 8%, 9%, 10%, 12% and
14% cement content upon stabilization of A-2-7(0) laterite soil
of cement grade 42.5N, 42.5R and 32.5N. Also in the Figure 9,
cement grade 32.5N proffered the highest CBR values of
specimens as indicated by their respective values with 79.25%,
92.5%, 107.25%, 113% and 122.25% as compared to related
values while using cement grades 42.5N and 42.5R. Figure 10
displays the variation of soaked California Bearing Ratio of the
A-2-7(0) laterite soil stabilized with grades 42.5N, 42.5R and
32.5N cements separately. This figure indicates that the soaked
California Bearing Ratio value at 0% of A-2-7(0) natural
laterite soil is 9.5% which is satisfactory because it is between
5% and 11% CBR standard range values recommended for
highway subgrade or foundation. Also at 4% of A-2-7(0)
laterite soil-42.5N, 42.5R and 32.5N cement stabilization the
soaked CBR values are 59.5%, 59.75% and 61.5% respectively
which are of higher than 30% standard recommendation at
maximum for highway subbase. Furthermore, Figure 10
displays the soaked CBR values at 6%, 7%, 8%, 9%, 10%, 12%
and 14% cement content upon stabilization of A-2-7(0) laterite
soil of cement grade 42.5N, 42.5R and 32.5N. In the figure,
cement grade 32.5N proffered highest CBR values of stabilized
specimens as indicated by their respective values with 88%,
110.25%, 124%, 148.5% and 166.25% while comparing same
related values of cement grades 42.5N and 42.5R.
Figure 9: Variation of unsoaked California Bearing Ratio
with varying amount of cement content upon A-2-7(0)
laterite soil stabilization
International Journal of Engineering and Technology (IJET) – Volume 6 No. 6, June, 2016
ISSN: 2049-3444 © 2016 – IJET Publications UK. All rights reserved. 188
Figure 10: Variation of soaked California Bearing Ratio
with varying amount of cement content upon A-2-7(0)
laterite soil stabilization
Figure 11 illustrates the relationship between unsoaked CBR of
A-2-7(0) laterite soil stabilized with grade 32.5N and 42.5N
cements separately. This correlation graph follows a linear
pattern with coefficient of determination 9976.02 R and
correlation 9987.0R of Equation 1.
7854.20004.1 xy (1)
Also, Figure 12 demonstrates the relationship between
unsoaked CBR of A-2-7(0) laterite soil stabilized with grades
32.5N and 42.5R cements individually. This correlation graph
follows a linear pattern with coefficient of determination
9868.02 R and correlation 9934.0R of Equation 2.
9818.29671.0 xy (2)
Likewise, Figure 13 validates the relationship between
unsoaked CBR of A-2-7(0) laterite soil stabilized with grades
32.5N and 42.5N cements separately. Correlation graph
developed follows a linear model with coefficient of
determination 9995.02 R and correlation 9997.0R of
Equation 3.
3522.0964.0 xy (3)
Correspondingly, Figure 14 exhibits the relationship between
unsoaked CBR of A-2-7(0) laterite soil stabilized with cement
grades 32.5N and 42.5R individually. Correlation diagram
developed follows a linear model with coefficient of
determination 998.02 R and correlation 999.0R of
Equation 4.
7854.20004.1 xy (4)
Figure 11: Relationship between unsoaked CBR values
resulted from using grades 42.5N and 32.5N cements
separately of the stabilized A-2-7(0) laterite soil
Figure 12: Relationship between unsoaked CBR values
resulted from using grades 42.5R and 32.5N cements
separately of the stabilized A-2-7(0)laterite soil
Figure 13: Relationship between soaked CBR values
resulted from using grades 42.5N and 32.5N cements
separately of the stabilized A-2-7(0) laterite soil
International Journal of Engineering and Technology (IJET) – Volume 6 No. 6, June, 2016
ISSN: 2049-3444 © 2016 – IJET Publications UK. All rights reserved. 189
Figure 14: Relationship between soaked CBR values
resulted from using grades 42.5R and 32.5N cements
separately of the stabilized A-2-7(0) laterite soil
4. CONCLUSIONS AND
RECOMMENDATIONS
A natural laterite soil sample from a road borrow pit in Ondo
town environs in Ondo State of Nigeria was tested in the
laboratory to determine its basic soil properties, Atterberg
limits, grain size analysis, compaction, unconfined compressive
strength and California Bearing Ratio. The soil sample was
further tested in the laboratory by chemical stabilization using
cements of grades 42.5N, 42.5R and 32.5N individually in
percentages of 4%, 6%, 8%, 10%, 12% and 14%. Based upon
the study, the following are the conclusions and able
recommendations.
1. The result of the grain size analysis and Atterberg limit
tests show that the laterite soil sample experimented is A-
2-7(0) laterite soil material and it is a granular clayey
gravel and sand that is good for subgrade.
2. The lower the optimum moisture content of the stabilized
soil specimen the higher the maximum dry density. At
maximum cement content of 14% of A-2-7(0) laterite soil
stabilization of the three types of cement individually,
grade 32.5N cement has the lowest value of OMC that is
15.4% and also has highest amount of MDD value which is
1.966 Mg/m³.
3. The higher the cement content of the stabilized soil
specimen the higher the CBR value for both unsoaked and
soaked specimens. At maximum cement content of 14% of
A-2-7(0) laterite soil stabilization with the three types of
cement individually, grade 32.5N cement has the highest
values of unsoaked and soaked CBR of 122.25% and
166.50% respectively.
4. The higher the cement content of the stabilized soil
specimen the higher the UCS as well as the strain for both
uncured and cured specimens. At maximum cement
content of 14% of A-2-7(0) laterite soil stabilization with
the three types of cement individually, grade 32.5N cement
has the highest values of respective uncured and cured
UCS of 217.391 2/ mkN and 296.443 2/ mkN respectively
with each having the strain value of 3.
5. There is strong relationship between the stabilized A-2-
7(0) laterite soil specimens with cement grades 32.5N and
42.5 R for unsoaked and soaked CBR because their
correlation R values are 0.9934 and 0.999 respectively.
However, stronger relationship exists between the
stabilized A-2-7(0) laterite soil specimens with cement
grades 32.5N and 42.5N for unsoaked and soaked CBR
because their correlation R values are 0.9987 and 0.9997
respectively.
6. With the availability of the three cements of grades 32.5N,
42.5N and 42.5 R for the stabilization of A-2-7(0) laterite
soil, the cement grade 32.5N is most viable economical.
However, in its absence cement grade 42.5N is preferable
to cement grade 42.5R.
7. Cement grade 32.5N at 8% cement content stabilization of
A-2-7(0) laterite soil proffered optimal strength of
188.867 2/ mkN and 208.748 2/ mkN respectively for
uncured and cured UCS for highway pavement design
while comparing same with the other cement of grades
42.5N and 42.5R with the values 178.218 and
199.60 2/ mkN for the former before 159.046 and
188.680 2/ mkN for the later. Kadyali and Lal (2008)
declared basecourse strength value between 170.00 2/ mkN and 276.00 2/ mkN as design criterion for soil-
cement stabilization in terms of the unconfined
compressive strength after 7 days moist curing.
8. Also, cement grade 32.5N at 8% cement content
stabilization of A-2-7(0) laterite soil proffered optimal
strength of 92.5% and 110.25% respectively for unsoaked
and soaked CBR for highway pavement design while
comparing same with the other cement of grades 42.5N
and 42.5R with the values 91.1% and 107% for the former
before 89.25% and 102.5% for the later. Kadyali and Lal
(2008) declared basecourse strength value between 80%
and 100% as design criterion for soil-cement stabilization
in terms of soaked CBR test.
REFERENCES AASHTO (2007): “Standard Specifications for Transportation
Materials and Methods of Sampling and Testing”,
American Association of State Highway and Transportation
Officials, 27th ed., Washington D.C
Akiije, I. (2015): “Comparison Characterization of A-6(10)
Laterite Soil Stabilized With Powermax Cement and Hydrated
Lime Separately”, International Journal of Engineering and
Technology, Volume 5 No. 7, 392-401
Akinwumi, I. (2014): “Plasticity, Strength and Permeability of
Reclaimed Asphalt Pavement and Lateritic Soil Blends”,
International Journal of Scientific & Engineering Research,
Volume 5, Issue 6, 631 - 636
International Journal of Engineering and Technology (IJET) – Volume 6 No. 6, June, 2016
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