CHAPTER
ONE
INTRODUCTION
Soil is the cheapest and the most
widely used material in civil engineering projects as foundation material
either in its natural or improved form. It is highly heterogenous and an
isotropic in nature and existing with different engineering properties which
can be influenced to some extent by the presence of copper salt under the influence
of water (Kadiyah and Lal, 2006).
The properties of soil as engineering
material depends on its surface electrical charges, chemical composition size
and shape e.t.c. The chemical composition influences the exhibition of enormous
changes in the engineering properties especially in soil with high content of
clay materials (Singh and Singh, 2006).
The geotechnical characteristics of
soil are of great importance. The degree of these properties within certain
range has a useful meaning in determining the best and suitability of it, for
engineering construction especially for road construction (Ola, 2005).
1.1 Lateritic Soil
Laterite is well known in Asian
countries as a building material for more than 1000 years. It was excavated
from the soil and cut in form of large blocks; temples at Angkor are famous,
examples for this early use.
Laterite is one of the most valuable
materials for building. It is diffused in immense masses, without any
appearance of stratification and is placed over the granite that forms the
basis of Malayala. It is full of cavities and pores, and contains a very large
quantity of iron in the form of yellow and red ochres. In the mass while
excluded from the air, it is so soft, that any iron instrument readily cuts it,
and is dug up in square masses with a pick-axe, and immediately cut into the
shape wanted with a trowel, or large knife. It very soon after becomes as hard
as brick and resists the air and water much better than any brick (Werner
Schellmann, 1991).
The engineering behaviour of laterite
material from trial pits is influenced by some factors which includes origin
degree of weathering, mineral composition, environmental condition e.t.c.
(Umebulues, 2001).
The result of these properties helps a
lot and will serve as a guide in prospective works. This will also provide
engineers with quick method of checking which material is best fit on the
alternative for road construction (Clarke, 2007).
1.0.1
The importance of laterite as building
material has already been mentioned. More relevant as their local use for the
construction of simple houses in their application as a road building material.
The suitability of lateritic materials above all of lateritic gravel is tested
by several methods of engineering geology.
1.1 Statement of the Problem
Misunderstanding soils and their
properties can lead to construction errors. The suitability of a soil for a
particular use should be determined based on it engineering characteristics and
not on usual inspection or apparent similarity to other soil.
Some particles of laterite tend to
crush easily under impart disintegrating into a soil may be self hardening when
exposed to drying or if they are not self hardening, they may contain
appreciable amounts of hardened lateritic rock or gravel.
1.2 Aim and Objectives
The aim and objectives of this project
include:
1.
To determine how suitable and
durable the available laterite material in Ilorin East Local Government is for
road construction.
2.
To carryout some geotechnical
tests required for the strength evaluation of laterite material in order to
determine its constructional suitability in road construction.
3.
To determine the strength of
laterite and its durability.
4.
To determine whether these
laterite materials meet the American Standard Test Method (ASTM) specification
for road construction.
5.
To draw conclusion and
recommendation from the evaluation as a standard for prescription of trial pits
selected in Ilorin East Local Government Area to Engineers and Construction
Industries.
1.3 Justification of Study
Due to the fact that laterite is a
paramount material in the construction of road, it has to be investigated to
determine its suitability for the construction of our roads.
1.4 Scope of the Project
The knowledge of the use of laterite
for road construction is increasingly going far and wide over the years.
For the purpose of this research, the
study shall be limited to Ilorin East Local Government Area of Kwara State in
which the following laboratory test will be carried out on each samples of
soil, the laboratory test are particle size distribution test. Atterberg’s
limit test, compaction test, Natural Moisture Content and Califonia Bearing
Ratio (CBR) test.
1.5 Methodology
This project will deal with the field
and laboratory test of laterite material for road construction. Three different
trial pit in Ilorin East Local Government Area will be selected.
The sample will be
collected from three trial pit locations and will be labeled thus:
SAMPLE A
SAMPLE B
SAMPLE C
The engineering tests required for
strength evaluation will be carried out such tests include CBR, Atterberg limit
test, particle size distribution test, compaction test and natural moisture
content.
The analysis of the result follows and
the conclusion and recommendation were made.