article - Journal of Emerging Trends in Engineering and

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article - Journal of Emerging Trends in Engineering and
Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(1): 49- 56
© Scholarlink Research Institute Journals, 2015 (ISSN: 2141-7016)
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Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(1):49- 56 (ISSN: 2141-7016)
Comparative Analysis of Cement and Lime Modification of
Ikpayongo Laterite for Effective and Economic Stabilization
Manasseh Joel and Joseph Ejelikwu Edeh
1
Department of Civil Engineering,
University of Agriculture, Makurdi, 970001, Nigeria.
Corresponding Author: Manasseh Joel
_________________________________________________________________________________________
Abstract
Some geotechnical properties of laterite obtained from Ikpayongo treated with 2 to 10 % cement was compared
with the same laterite treated with 2 to 10 % Lime, to determine the most suitable modifier for effective and
economic stabilization. Modification potential was assessed using Atterbeg’s limits test, while California
bearing ratio (CBR) and unconfined compressive strength (UCS) tests were used to ascertain strength gain with
additives concentration. The plasticity index of the natural laterite reduced from 16 % to 7 % and 4 %
respectively, when treated with 10 % cement and lime respectively. 7 day UCS value of laterite increased from
534 kN/m2 to maximum values of 1255 kN/m2 and 1090 kN/m2 respectively, when treated with 10% cement and
10 % lime respectively. California bearing ratio (CBR) value increased from 28 % to 135 % and 100 % when
treated with 10 % cement and lime respectively. Based on results obtained from the study, treatment of
Ikpayongo laterite with 6 % cement or 4 % lime will effectively modify it for economic stabilization. The use of
4 % lime is recommended for modification of Ikpayongo laterite, as the use of excess cement might lead to
cracks in the stabilized layer, even though economic analysis is in favour of the use of cement. Results of tests
from the study will serve as a guide in the selection of an appropriate modifier for effective stabilization of
laterite for roadwork.
__________________________________________________________________________________________
Keywords: cement, lime, ikpayongo laterite, modification
conditions of combined silica and bases and the
relative accumulation or enrichment from outside
sources (absolute accumulation) of oxides and
hydroxides of sesquioxides (mainly Al2 O3, and
Fe2O3, the most resistant components to leaching).
The third stage (dehydration or desiccation) involves
partial or complete dehydration (Sometimes
involving hardening) of the sesquioxide rich
materials and secondary minerals.
INTRODUCTION
The importance of road in the development of any
nation can hardly be over emphasized, as it plays a
crucial role in the transportation of goods and
services. This is normally achieved through the vast
network of roads that connect rural and urban centers.
Efforts at achieving the construction of more roads is
hindered by the high cost of building new roads,
attributed to the non availability of suitable road
building materials within the vicinity of most road
projects. Laterite, a sedimentary rock deposit arising
from the weathering of rocks, is one of the most
common and readily available road building materials
that can be sourced locally in Nigeria. Laterite has
been defined by different authors using different
criteria, but for simplicity and ease of understanding
laterite as defined by Ola (1983) as the products of
tropical weathering with red, reddish brown, and dark
brown colour, with or without nodules or concreting
and generally (but not exclusively) found below
hardened ferruginous crust or hard pan, will be
adopted in this study.
GEOLOGY OF IKPAYONGO LATERITE
At Ikpayongo, a distance of 22km from Makurdi, the
capital of Benue State of Nigeria, West- Africa, is
found a deposit of laterite, divided into two equal
parts by the main road linking Makurdi to Otukpa.
Ikpayongo laterite is located in the Benue trough
(which is more than 800 kilometers in length and
varies in width from 100 kilometers in the south to
about 150 kilometers in the north. The Benue trough
is conventionally divided into three sections; the
lower, Middle and the Upper. According to
(Rahaman and Malomo, 1983) sedimentation in all
the sections started in the cretaceous (Albian) and
ended
at
Upper-most
Cretaceous
times
(Maestrichtian). The lower section where Ikpayongo
laterite deposit is situated is dominated by the
Abakaliki anticlinorium. Maximum thickness in the
lower section estimated by Cratchley and Jones
(1965) from gravity a study probably does not exceed
4300 meters. Ford (1989) describe laterite found in
Laterite formation process can be categorize into
three major stages namely; decomposition, leaching
and dehydration/desiccation. The first stage is
decomposition which is characterized by physical and
chemical break down of primary minerals and the
release of constituent elements. The second stage
involves the leaching, under appropriate drainage
49
Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(1):49- 56 (ISSN: 2141-7016)
cement, based on findings by (Joel and Agbede,
2011; Eze-Uzomaka and Agbo, 2010) this
observation clearly shows that there is need for a
modifier or admixture in the stabilization of
Ikpayongo laterite with cement. Although cement and
lime have been used for modification/stabilization of
soil, there is need for a study that will help identify
the most effective modifying agent that will upgrade
the geotechnical properties of Ikpayongo laterite to a
level that economic stabilization with cement can be
achieved. The study is restricted to the use of cement
and lime, due to their availability and cost.
the Benue trough as a residual weathering product on
partially or wholly decomposed basalts and other
basic to intermediate igneous rocks. Other
sedimentary deposits that characterize the trough are
limestone, clay and shale. Limestone deposits exist at
different locations in the Benue trough, such
locations within the lower Benue trough are Gboko,
Igumale and Nkalagu, where different cement
factories are being situated. The abundance of clay
and shale formation is also a noticeable feature of the
lower Benue trough. All this could help one
understand the origin and formation of laterite at
Ikpayongo, this may have been the outcome of the
weathering of basalts, which resulted in products like
limestone, clay, shale and laterite, all possible
products of the weathering of basalts within the
trough.
An admixture or a modifier according to Punmia
(2005) refers to certain chemicals sometimes added
to soil-cement, to reduce the cement consumption or
make a soil suitable for stabilization, when not
responsive to cement alone in its natural state. Lime
and calcium chloride are common chemicals
normally applied to soils containing clays or organic
matter. When the amount of cement added is
insufficient to harden the soil enough to meet soilcement stability and durability criteria, cement usage
under such condition according to O’Flaherty (1974)
is aimed at modification, as the resultant material
may fragment under the action of traffic, high waterholding capacities and volume change are
characteristics of such soil, which may cause
excessive distortion of pavements, due to low
supporting values, as their moisture content vary with
the weather.
The
geotechnical
characteristics
and
field
performance of lateritic soils, as well as their reaction
to different stabilising agents according to Makasa,
(2004) may be interpreted in the light of genesis and
pedological factors (parent material) degree of
weathering, clay-size content, depth of soil in the
profile. The behaviour of laterite soils in pavement
structure has been found to depend mainly on their
particle-size characteristics, the nature and strength of
the gravel particles, the degree to which the soils
have been compacted, as well as the traffic and
environmental conditions. Well-graded laterite
gravels according to Thagesen (1996) perform
satisfactorily as unbound road foundations. However,
where laterite is gap-graded with depleted sandfraction, contain a variable quantity of fines, have
coarse particles of variable strength which may break
down, their usefulness as pavement materials on
roads with heavy traffic will be threatened.
In Makurdi, the capital of Benue state, Nigeria
Ikpayonog laterite is the main source of borrow
material for road construction. It has been used as
base and sub-base course material of most of the
flexible pavement built within the metropolis.
Different types of defects have been observed in
almost all the areas where the natural laterite was
used as sub-base or base material, this observation is
a pointer to the fact that the suitability of the material
needs to be assessed. In the past practicing engineers
and researchers, have observed that deficiencies
associated with laterite can be overcome through
different forms of treatment, which in most cases is
aimed at modifying or stabilizing the material.
The term soil modification as described by Osula
(1996) and Sariossieri and Muhunthan (2009) applies
to a significant improvement of the soil workability
and compaction characteristics and to a minor
improvement of the soil mechanical strength using
low contents of stabilizers. The addition of a modifier
(cement and lime) etc to a soil to change index
properties according to Alhassan and Mustapha
(2011) is called modification. Modification according
to Eluozo and Nwaobakata (2013) refers to soil
improvement that occurs in the short term, during or
shortly after mixing (within hours). It is aimed at
reducing plasticity of the soil to the desired level,
short term strength gain, (i.e. strength derived
immediately after application to about 7-days of
compaction). In summary soil modification may or
may not lead to strength increase but results in the
alteration of soil properties to enhance workability, as
evidence in textural changes that accompany
consistency improvements.
Lime and cement have been meaningfully used for
soil stabilization and modification (Reids and Brooks,
1999; Basha, et al, 2005; Eze-Uzomaka and Agbo,
2010; Joel and Agbede, 2011; Joel and Agbede,
2010). Laterite from Ikpayongo is not suitable for use
as sub-base and base material and cannot be treated
economically for use as pavement material with only
Researchers have postulated that the use of cement
for soil stabilization will be very effective when the
plasticity index of the soil is less than 10 %, findings
by (Garber and Hoel, 2010; Yoder and Witczak,
1975) indicate that where plasticity index value is
greater than 10 % more cement will be required for
effective stabilization, a situation that normally leads
50
Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(1):49- 56 (ISSN: 2141-7016)
geotechnical test on laterite samples obtained from
Ikpayongo, treated with cement and lime. Results
from such tests will be used in the determination of
the most effective modifier for economic stabilization
of Ikpayongo laterite with cement.
to uneconomic stabilization of such soil. An
alternative to the use of high percentage of cement is
the use of lime as a modifier to reduce the plasticity
index of the soil before stabilization with cement.
Soil modification ability of cement and lime in this
study will be assessed using the plasticity index
value, with a minimum plasticity index value of 10 %
being indices for effective modification as suggested
by (Garber and Hoel, 2010).
MATERIALS AND METHODS
Laterite sample were collected from Ikpayongo,
located at a distance of 22 kilometres from Makurdi,
the capital of Benue State, Nigeria, along MakurdiOtukpo road. The borrow pit was located at a
distance of 500 m and at an angle of 90° West from
the centre line of the road. Disturbed samples were
collected from the depth of 0.5 to 2.0 m after the
removal of the top soil. Ordinary Portland cement
and hydrated lime as obtained from the open market
in Makurdi was used for the work. Analysis of
chemical components of ordinary Portland cement
and lime was carried out using x-ray analyzer
together with Atomic Absorption Spectrophotometer
(AAS).
Advantages to be derived from the practical
application of lime for soil modification according to
(NLA, 2004) are “dry-up” of wet soil at construction
sites to aid compaction, drying out of wet areas to
help bridge across underlying spongy subsoil,
provision of working table for subsequent
construction, conditioning of soil through pretreatment for further stabilization with Portland
cement or bitumen.
Changes in the physical properties of soil observed
when treated with cement is attributed to the
hydration of calcium-silicates and calcium aluminates
in Portland cement and pozzolanic reactivity between
released lime and silica and alumina released from
clay minerals. When hydrated lime is used in soil
modification, the calcium ions from hydrated lime
migrate to the surface of the clay particles and
displace water and other ions. The soil becomes
friable and granular, making it easier to compact. The
plasticity index of the soil also decreases as well as
its tendency to swell and shrink. This process is
called flocculation and agglomeration, and occurs
within minutes, this is the reaction that plays key role
in soil modification. The reaction responsible for
strength gain is the pozzolanic reaction, which occurs
when silica and alumina released from clay mineral
in a high pH environment react with calcium from the
lime to form calcium-silicate-hydrates (CSH) and
calcium-aluminate-hydrate (CAH). Which are
cementitous products similar to those formed during
cement hydration to form the matrix that contributes
to the strength of lime-stabilized soil layers, and such
reactions goes into days.
Specimens of Soil samples used for different
laboratory test were prepared by treating laterite with
cement and hydrated lime in proportions of 0 %, 2 %,
4 %, 6 %, 8 % and 10 % by dry weight of laterite.
Laboratory tests were performed on the sample
obtained from Ikpayongo in accordance with BS1377
(1990) for the natural laterite and BS1924 (1990) for
laterite mixed with cement and lime. California
bearing ratio (CBR) tests were conducted in
accordance with the Nigerian General Specification
(1997) which stipulated that specimens be cured in
the dry for six days then soaked for 24 hours before
testing. Tests performed on Ikpayongo laterite sample
mixed with cement, and hydrated lime, include
Atterberg’s limits tests, compaction tests, Unconfined
Compressive strength (UCS) tests and California
bearing ratio tests.
Compaction was carried out using the West African
standard compactive effort, because it was the
conventional energy level commonly used in the
region and recommended by the Nigerian General
Specification (1997). The compactive effort was
achieved using energy derived from a rammer of 4.5
kg mass falling through a height of 45 cm in a
1000cm3 mould. The soil was compacted in five
layers, each layer receiving 10 blows The resistance
to loss in strength was determined as a ratio of the
unconfined compressive strength (UCS) of specimens
cured for 7 days under controlled conditions, which
were subsequently immersed in water for another 7
days to the UCS of specimens cured for 14 days. The
particle size distribution of Ikpayongo laterite was
determined using the wet sieving method.
The geotechnical and engineering properties of
lateritic soils have been researched into in the
northern, eastern, western and southern part of
Nigeria. (Ola, 1983; Gidigasu and Kuma, 1987;
Adeyemi, 2002; Oladeji and Raheem 2002; Bello,
2007; Bello and Adegoke; 2010), not much has been
done on laterite found in the Benue trough, where
Ikpayongo laterite deposit, found in the middle belt
region of Nigeria is located. Since the properties of
latertie varies with age of formation, location, and is
not fixed, there is need for such a study, which is
aimed at comparing the effectiveness of lime and
cement in the modification of Ikpayongo laterite for
effective and economic stabilization. The aim of the
study will be achieved through the conduct of basic
51
Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(1):49- 56 (ISSN: 2141-7016)
lime used is summarized in Table 1. Summary of the
result of test on the natural laterite is reflected in
Table 2.
RESULTS AND DISCUSSION
The grain size distribution curves of Ikpayongo
laterite is presented in (Figure 1), the chemical
component of ordinary Portland cement and hydrated
Table 1: Chemical Composition of CCR and Cement
Oxides
Concentration (%)
Lime
Cement
CaO
67.08
64.0
MgO
1.26
1.94
Al2O3
0.50
5.75
Fe2O3
0.03
2.50
SiO2
1.54
20.4
MnO
0.05
-
TiO2
0.32
-
K2 O
0.05
0.61
Na2O
0.02
0.40
SO3
2.73
LOI: Loss on Ignition.
The natural Ikpayongo laterite liquid limit value of 36
% shows that the material can be classified as having
intermediate plasticity. This is based on Whitlow
(1995) classification of materials with liquid limit
less than 35 % being indicative of low plasticity,
between 35 % and 50 % and between 51 % and 70 %
being indicative of intermediate and high plasticity
respectively, while values greater than 70 % is
indicative of very high plasticity.
The effect of cement and lime on the Atterberg’s
limits values of Ikpayongo laterite treated with
cement and lime is presented in (Tables 3 and 4),
respectively.
Table 3: Variation of Liquid limit, Plastic limit and
Plasticity Index of Ikpayongo laterite with Cement
Content
Ikpayongo laterite was found to be an A-2-6 and GP
soil by the AASHTO and Unified Soil Classification
systems (USCS) respectively. The specific gravities
of Ikpayongo laterite, cement and lime were
determined as 2.69, 2.20, and 3.15 respectively. The
geotechnical properties of Ikpayongo laterite clearly
shows that it is only suitable for use as fill material
and not sub-base and base material based on the
Nigerian General Specification (1997). Soil
stabilization is normally used to make such soil
suitable for use as sub-base and base material.
However, effective and economic stabilization with
cement cannot be achieved based on report by (EzeUzomaka and Agbo, 2010; Joel and Agbede, 2011).
This observation clearly shows that there is need for
the modification of Ikpayongo laterite for effective
and economic stabilization.
Cement Content (%)
Liquid Limit (%)
Plastic Limit (%)
Plasticity Index (%)
Natural Moisture Content (%)
2
36
21
15
4
34
22
12
6
33
23
10
8
32
23
9
10
31
24
7
Table 4: Variation of Liquid limit, Plastic limit and
Plasticity Index of Ikpayongo laterite, with Lime
Content
Lime Content (%)
Liquid Limit (%)
Plastic Limit (%)
Plasticity Index (%)
0
36
20
16
2
35
22
13
4
32
23
9
6
31
24
7
8
30
25
6
10
29
25
4
The liquid limit of Ikpayongo laterite decreased with
cement and lime content, while the plastic limit
increase with cement and lime content, resulting in
the decrease of plasticity index with cement and lime
content. The trend observed with Atterberg’s limits
indices and cement content can be attributed to the
hydration reaction of cement. The trend observed
with lime can be attributed to agglomeration of fine
clay particles into coarse, friable particles by a base
exchange with the calcium cation from lime
displacing sodium or hydrogen ions, with a
subsequent dewatering of the clay fraction of the
laterite, referred to as cation exchange reaction.
Table 2: Some Geotechnical Properties of Ikpayongo
Laterite
PROPERTY
Percentage Passing BS Sieve No 200 (%)
Liquid Limit, (%)
Plastic Limit (%)
Plasticity Index (%)
AASHTO Classification
USCS Classification
Maximum Dry Density,Mg/m3
Optimum Moisture Content (%)
Unconfined Compressive Strength KN/m2
California Bearing Ratio,% (after 24hrs soaking)
Specific Gravity
Colour
0
36
20
16
QUANTITY
45.5
36.0
20.0
16.0
A-2-6
GP
1.86
12.0
534
28
2.69
Reddish
brown
7.24
The plasticity index value of Ikpayongo laterite
decreased from 16 % to 7 % and 4 % respectively
when treated with 10 % cement and lime content
respectively. The minimum plasticity index value of
10 % to be attained by soil for effective stabilization
with cement, recommended by (Garber and Hoel,
2010; Yoder and Witczak, 1975) was achieved with
52
LOI
26.85
1.20
Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(1):49- 56 (ISSN: 2141-7016)
the use of 6 % cement and 4 % lime content
respectively. The use of hydrated lime to treat
Ikpayongo laterite was more effective in reducing
plasticity index than the use of cement, as more
calcium ions was made available for reaction with the
clay particles by the hydrated lime during cation
exchange than the free lime release for reaction with
clay particles during the hydration of cement. The
implication of the result is that effective stabilization
of Ikpayongo laterite with cement begins after the
addition of 6 % cement, or after the addition of 4 %
lime.
to more moisture required for cation exchange and
pozzolanic reaction of lime.
Soil modification does not necessarily mean strength
attainment, however, the strength criterion used in
selecting materials for sub-base and base which is
stability, measured in terms of the California bearing
ratio (CBR) and unconfined compressive strength
(UCS) which are indirect tests, will be used to
evaluate the strength gain during modification
process. Durability of material will be assessed using
resistance to loss of strength measured using
unconfined compressive strength specified by Ola
(1974).
Variation of maximum dry density and optimum
moisture content of Ikpayongo laterite with cement
and lime content is as presented in (Tables 5 and 6)
respectively.
The effect of lime and cement on the California
bearing ratio (CBR), and UCS values of Ikpayongo
laterite is presented in Tables 7 and 8 respectively.
Table 5: Variation of Maximum Dry Density and
Optimum Moisture Content of Ikpayongo laterite,
with Cement Content
Cement Content
(%)
Maximum Dry
Density (MDD)
Mg/m3 .
Optimum
Moisture Content
(OMC) %.
0
2
4
6
8
10
1.86
1.88
1.90
1.93
1.95
1.98
12.0
12.5
13.0
14.0
15.0
16.0
Table 7: Strength Indices and Durability value of
Ikpayongo Laterite treated with cement
Cement
content (%)
7 day UCS
(kN/m2)
14 day UCS
(kN/m2)
28 day UCS
(kN/m2)
Durability
(%)
CBR (%)
Table 6: Variation of Maximum Dry Density and
Optimum Moisture Content of Ikpayongo laterite,
with Lime Content
Lime
Content
(%)
Maximum Dry
Density (MDD)
Mg/m3 .
Optimum
Moisture Content
(OMC) %.
0
2
4
6
8
10
1.86
1.87
1.88
1.89
1.91
1.93
12.0
13.5
14.0
15.0
17.0
19.0
0
2
4
6
8
10
534
606
723
872
1044
1255
534
733
879
1059
1268.0
1518
534
861
1034
1240
1492
1788
0
20
38
55
65
75
28
70
90
100
120
135
7 day UCS= seven days Unconfined Compressive
strength test.
14 day UCS= Fourteen days Unconfined
Compressive strength test.
28 day UCS= Twenty-eight days Unconfined
Compressive strength test.
CBR = California Bearing ratio
Table 8: Strength Indices and Durability value of
Ikpayongo Laterite treated with Lime
Maximum dry density of Ikpayongo laterite increased
with cement and lime content. Increased maximum
dry density may be due to a decrease in the surface
area of the clay fraction of Ikpayongo laterite arising
from the substitution of Ikpayongo laterite with
cement or lime, the increase associated with lime can
be attributed to the cation exchange and aggregation
arising from the use of lime, while increase with
cement is due to the hydration of cement. The
maximum dry density of the untreated laterite
increased from 1.86 Mg/m3 to 1.98 Mg/m3 and 1.93
Mg/m3 when treated with cement and lime
respectively. Increase in maximum dry density with
cement and lime content according to Amu et al
(2011) is indicative of improvements in the soil
properties. Optimum moisture content of Ikpayongo
laterite increased from 12 % to 16 % and 19 % when
treated with cement and lime respectively. The
increase in optimum moisture content with cement is
due to more moisture required for effective hydration
of cement, while increase with lime can be attributed
Cement
content (%)
7 day UCS
(kN/m2)
14 day UCS
(kN/m2)
28 day UCS
(kN/m2)
Durability
(%)
CBR (%)
0
2
4
6
8
10
534
581
600
711
993
1090
534
642
835
900
1179.3
1297
534
700
988
1054
1287.9
1400
0
31
50
60
70
80
28
50
60
75
90
100
7 day UCS= seven days Unconfined Compressive
strength test.
14 day UCS= Fourteen days Unconfined
Compressive strength test.
28 day UCS= Twenty-eight days Unconfined
Compressive strength test.
CBR = California Bearing ratio
The California bearing ratio of untreated Ikpayongo
laterite increased from 28 % to maximum value of
135 % and 100 % when treated with 10 % cement
53
Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(1):49- 56 (ISSN: 2141-7016)
Table 9: Cost of Different percentages of lime and
cement required for the modification of 1 Metric Ton
(1,000 Kg) of Ikpayongo Laterite.
and 10 lime respectively. Increase in California
bearing ratio with cement can be attributed to the
hydration reaction of cement, while that associated
with the use of lime, can be attributed to the cation
exchange and pozzolanic reaction of lime. Increase in
California bearing ratio value with cement and lime
content is an indication of the suitability of lime and
cement for use in the modification of the laterite. The
result also shows that the singular use of cement even
up to 10 % cannot effectively stabilize the soil for use
as base material as the maximum California bearing
ratio values arising from their singular usage is less
than the value of 180 % Specified by the Nigerian
General Specification (1997) hence the need for
modification.
Additive
Content
(%)
Cost
of
Cement N
Cost
of
Lime N
0
2
4
6
8
10
0
720
1,440
2,160
2,880
3,600
0
2,800
5,600
8,400
11,200
14,000
Cost analysis clearly shows that the cost of using
lime for soil modification is about 3.9 times the cost
of using cement. Cost increases with cement and lime
content, as the cost of modification with 10 % cement
and 10 % lime is N 3,600 and N 14, 000 respectively.
The cost of modifying Ikpayongo Laterite with 4 %
lime, which is N 5,600 as against N 2,160 required
with the use of 6 % cement for effective modification
before stabilization with cement or other additives.
Clearly shows that it is more economical to use 6 %
cement for modification than 4 % lime, however
other factors such as durability and cracks in layers
should be considered before a final conclusion is
drawn.
The variation of 7 day UCS, 14 day UCS and 28 day
UCS values with cement and lime content presented
in Table 7 and 8, clearly shows that UCS value
increase with days, cement and lime content. The
maximum 7 day UCS value of 1255kN/m2 and 1090
kN/m2 obtained with the use of 10 % cement and
lime respectively, is lower than the value of 1720
kN/m2 specified by Millard (1993) an indication that
only cement or lime cannot effectively stabilized
Ikpayongo laterite.
CONCLUSIONS
The use of cement and lime in the modification of
Ikpayongo laterite has effect on the Atterberg’s limts
value and strength indices of the laterite. The use of
lime in the reduction of plasticity index is more
effective than the use of cement, more cement is
required for effective modification than lime as the
plasticity index value of Ikpayongo laterite decreased
from 16 % to 7 % and 4 % respectively when treated
with 10 % cement and 10 % lime respectively.
Differences in strength observed with CBR and UCS
values can be attributed to the concentration of
cementing gel form, during the hydration of cement,
which is higher than that obtained from the
pozzolanic reaction of lime, in addition to the
hardening process of cementing gel being faster with
the use of cement than with lime. A situation
responsible for higher strength values observed with
the use of cement than was observed with lime.
Strength indices value of Ikpayongo laterite modified
with cement is higher than values obtained with
modification with lime, as the California bearing ratio
and 7 day UCS values increased from 28 % to 135 %
and 100 % respectively when treated with 10 %
cement and lime respectively, while the 7 day UCS
values increased from 534 kN/m2 to 1255 kN/m2 and
1090 kN/m2 respectively, when treated with 10 %
cement and lime respectively.
The resistance to loss of strength of Ikpayongo
laterite which disintegrated inside water in the
absence of a binder increased from 0 % to 75 % and
80 % respectively when treated with 10 % cement
and 10 % lime respectively. Resistance to loss of
strength value of 25 % attained at 10 % cement is
higher than the maximum loss of strength value of 20
% recommended by Ola (1974). An indication that a
modifier or more cement is required for effective
treatment of Ikpayongo laterite with cement. It is
worthy of note that the water retarding ability of lime
is higher than that of cement, a situation responsible
for higher durability values associated with lime
application.
Economic analysis clearly shows that it is more
economical to modify soil with cement than lime,
however, where cement is used as the stabilizer high
cement content might lead to cracks in the stabilized
layer, hence the recommendation of the use of lime in
such situation.
Cost analysis of using cement and lime in the
modification of Ikpayongo laterite is as presented in
(Table 9). The cost of 25 kg of lime is N 3,500, the
cost of 1 kg of lime will be N 140. The cost of 50 Kg
bag of cement is N 1,800, the cost of 1 Kg of cement
will be N 36.
Based on results of test, 4 % lime is recommended
for effective modification of Ikpayongo laterite
before stabilization with cement. In the bid to
overcome the problem of cracks likely to occur with
the use of high cement content, in addition to lime’s
ability to offer high resistance to loss of strength,
especially in areas where the water table is high.
54
Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS) 6(1):49- 56 (ISSN: 2141-7016)
Ford, O.S. (1989). The economic mineral resources
of the Benue trough, In: C.A. Kogbe, (ed.), Geology
of Nigeria, (pp 473-484 ). Jos, Nigeria: Rock View.
However, where other stabilizer such as bitumen or
tar is employed instead of cement, the use of 6 %
cement is recommended, for the modification of
Ikpayongo laterite.
Garber, J.N. and Hoel, L.A. (2010). Traffic and
Highway Engineering. Philadelphia, PA: Cengage
Learning.
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