ABSTRACT
Sustaining housing
development especially to the medium/low-income group of the society has become
a huge challenge particularly because of the huge capital outlay required to do
so. Thus, acquisition of indigenous building materials by way of Compressed Stabilized
Laterite Blocks (CSLBs) has been suggested as a way out. The aim of this research is to investigate the properties
of stabilized laterite blocks at 5%, 15%, and 25% stabilization.
The specific objectives
are; to determine the compressive strengths of the stabilized laterite block
samples at 5%, 15% and 25% cement stabilization; to investigate the water
absorption capacity of the stabilized laterite block samples at 5%, 15%, and
25% cement stabilization, and; to assess the resistance to abrasion of the
stabilized laterite block samples at 5%, 15% and 25% cement stabilization.
Laterite samples were collected from the Otta area in Ogun State, Nigeria;
based on previous work which stated that the samples obtained from this place
produced good interlocking blocks that met minimum standards. These samples
were stabilized with ordinary Portland cement using 0%, 5%, 15% and 25% by
weight of the binder; 0% stabilization being the control. The stabilized
samples were then used to produce stabilized blocks which were tested for
strength and durability.
TABLE OF CONTENT
CONTENTS PAGES
Title page i
Certification ii
Dedication iii
Acknowledgment iv
Abstract v
Table of contents vi
List of tables and
figures vii
References viii
Appendix ix
CHAPTER ONE
1.0 Introduction 1
1.1 Background to the Study 1
1.2 Statement of Research Problem 4
1.3 Aim and Objectives of the Study 4
1.4 Research Questionnaire 4
1.5 Significance of the Study 5
1.6 Scope and Limitation 5
1.7 Definition of key Terms 6
CHAPTER TWO
Literature
Review 9
2.0 Introduction 9
2.1Definition of Stabilized Blocks 9
2.2 Soil Cement Blocks as a Building Material 10
2.3 Durability of CSBs 12
2.3.1 Durability 13
2.3.2 Deterioration 13
2.3.3 Compaction and Densification 15
2.4 Stabilization of Laterite Blocks 16
2.4.1 Effect of Cement Content 16
2.5 Factors Affecting The Durability Of Earth Wall Buildings 18
2.6 Test Methods 21
2.6.1 Wire Brush Tests 21
2.6.1.1 ASTM D559 Wire Brush Test 21
2.6.2 Spray Tests 24
2.6.3 Bulletin 5 Spray Test 26
2.6.4 Dad’s Spray Test 28
2.6.5 Ogunye’s Spray Test 29
2.6.6 Drip Tests 31
2.6.7 Yttrup Drip Test 31
2.6.8 Compaction Between Drip Test and bulletin 5 Spray Test 33
2.6.9 Soaking Test – New Mexico Building Code 35
2.7 Load Bearing Capacity of Compressed Laterite Blocks 36
2.7.1 Strength Tests 36
2.7.2 Wet to Dry Strength Ratio 36
2.7.3 Correlation Between Compressive Strength and Durability 38
2.7.4 Surface Strength Tests 39
2.7.5 Penetrometer Tests 39
2.8 Effect of Age at Time of Testing 41
2.9 Summary 42
CHAPTER THREE
Research
Methods
3.0 Introduction 44
3.1 Experimental Procedure 44
3.1.1 Collection of Laterite Samples 44
3.1.2 Preparation of Laterite samples 44
3.1.3 Production of Stabilized Laterite Blocks 45
3.1.4 Curing of Stabilized Laterite Blocks 46
3.1.5 Testing of Stabilized Laterite Blocks 46
CHAPTER FOUR
Presentation
of Finding
4.0 Introduction 49
4.1 Results and Discussion 49
4.1.1 Durability of Cement Stabilized Lateritic Interlocking Blocks 49
4.1.2 Water Absorption of Cement Stabilized Lateritic Interlocking Blocks 50
4.1.3 Compressive Strengths of Cement Stabilized Lateritic
Interlocking Blocks 51
CHAPTER
FIVE
Conclusion
and Recommendation 53
5.0
Introduction 53
5.1
Conclusion 53
5.2
Recommendation 54
5.3 Area
of Further Studies 54
References
55
Appendix
57
LIST
OF TABLES
TABLES PAGES
Table 1: Batching Information for Laterite Samples Stabilized With Cement 46
Table
2: Showing Result
of Abrasive Test For Cement Stabilized Lateritic Interlocking Blocks. 49
Table
3: Showing Results
Of Water Absorption Test For Cement Stabilized Interlocking Blocks. 50
Table 4: Result of Compressive Strength
Test For Cement Stabilized Interlocking Blocks 51
CHAPTER
ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
The
importance of housing in human history cannot be overemphasized. Housing is
seen as one of the best indicators of a person’s standard of living and of his
or her place in society (UNCHS, 1993). Furthermore, Venkatarama (2004) is of
the view that housing and building conditions also reflect the living standards
of a society. Thus, the importance of access to adequate and affordable housing
took the front burner in the mid 20th century. The low-income group whose
population is on the increase due to rapid urbanization and population growth
evidently became the most vulnerable in terms of lack of access to decent and
affordable housing in developing countries. This has led to various researches
into development of locally available building materials and construction
techniques to enhance access to housing for all.
In
1976, the Human Settlements conference in Vancouver gave new impetus to this
approach, condemning the transposition of Western building techniques for
low-cost housing and recommending the design of technologies suited to
climatic, social and cultural contexts (Rigassi, 1985 cited in Alagbe, 2008).
The conference also recommended the gradual reduction of imports of products
and services linked to construction, and the drawing up of norms and regulations
which covered the basic needs of end-users whilst taking account of their
economic possibilities.
The
acquisition of local building materials and techniques to guarantee access to
decent and durable housing for all by the year 2000 was adopted in December
1988 by the General Assembly of the United Nations with the slogan “Global
Strategy for Housing to the year 2000”. The Assembly proposed relying on a vast
formal and informal private sector participation in housing provision. This
strategy was aimed at removing the dependence on the public sector for housing
provision by exploring the erstwhile ignored wealth of existing human resources
and their building cultures and social dynamics (UNCHS, 1993).
The
building culture of pre-independence Nigeria was an absolute dependence on
earth building techniques such as use of adobe bricks (sun-dried bricks) and
wattle and daub (mud wall construction). These techniques were predominant in
major rural and semi-urbanized towns and cities in Nigeria. These techniques
were durable, adequate and accessible enough for them to meet their housing
needs. The techniques were also sustainable since they do not deplete the
natural resources of the environment neither do their production processes lead
to the emission of gases that causes global climate change.
However,
post-independence rural centres in Nigeria acquired new status as a result of
independence on October 1, 1960. This period was immediately followed by the
“oil boom” of the 1970 and 1980 which brought about an unprecedented prosperity
and development of the nation. There were massive improvements on
infrastructural development particularly in state capitals and major cities and
towns. Thus, the towns became increasingly urbanized and became an
urban-oriented society. The crave for Western building techniques led to the
gradual extinction of the erstwhile earth building techniques. Thus, while
other countries were developing various earth building techniques to meet the
housing needs of their populace, the technique became associated with the poor
in Nigeria and not fashionable for housing purposes.
1.2 STATEMENT
OF THE RESEARCH PROBLEM
Sustaining
housing development especially to the medium/low-income group of the society
has become a huge challenge particularly because of the huge capital outlay
required to do so. Thus, acquisition of indigenous building materials by way of
Compressed Stabilized Laterite Bricks (CSLBs) has been suggested as a way out
(Alagbe, 2008).
Despite
the cost benefits of using stabilized blocks for building construction (Alagbe,
2008), the use of stabilized laterite blocks still appears to be on a low
profile. It is opined that this could be due to the properties of stabilized
laterite blocks. This research evaluates CSLBs as a building material for
sustainable housing construction and investigates the properties of CSLBs. The
study focuses primarily on evaluating its physical properties as a building
material as well as a measure of its level of acceptability for housing
construction among the populace.
1.3 AIM
AND OBJECTIVES OF THE STUDY
The aim of this research is to investigate the properties of
stabilized laterite blocks at 5%, 15%, and 25% stabilization.
The
specific objectives are;
i)
To determine the compressive strengths
of stabilized laterite block samples at 5%, 15% and 25% cement stabilization.
ii)
To investigate water absorption capacity
of stabilized laterite block samples at 5%, 15%, and 25% cement stabilization,
and
iii)
To assess the resistance to abrasion of stabilized
laterite block samples at 5%, 15% and 25% cement stabilization.
1.4 RESEARCH
QUESTIONS
The
research questions are;
i)
What are the compressive strengths of
stabilized laterite block samples at 5%, 15% and 25% cement stabilization?
ii)
What is the water absorption of
stabilized laterite block n at 5%, 15% and 25% cement stabilization?
iii)
What is the resistance to abrasion of
stabilized laterite block samples at 5%, 15% and 25% cement stabilization?
1.5 SIGNIFICANCE
OF THE STUDY
This
study has the following significance;
It shows the compressive strengths of
stabilized laterite blocks at 5%, 15% and 25% cement stabilization. This helps
in finding out if there is any significant difference in the compressive
strength at the various degrees of stabilization. This will aid decision making
when making stabilized bricks as it will inform what percentage of cement will
be needed to achieve a specific compressive strength.
The study finds out the water absorption
of stabilized laterite blocks at 5%, 15% and 25% cement stabilization. This
helps in finding out if there is any relationship between the degree of stabilization
and the water absorption capacity of stabilized laterite blocks. This will be
helpful when making stabilized bricks as it will inform what percentage of
cement will be needed to achieve certain degrees of water absorption.
It tells the resistance to abrasion of
stabilized laterite blocks at 5%, 15% and 25% cement stabilization. This helps
in finding out if there is any significant difference in the resistance to
abrasion at the various degrees of stabilization. This will aid decision making
when making stabilized bricks as it will inform what percentage of cement will
be needed to make the stabilized blocks resistant to abrasion.
1.6 SCOPE
AND LIMITATION
This
study will focus on making various laterite block samples with cement
stabilization at 5%, 15%, and 25%. The samples are cured and then made to
undergo laboratory tests to determine their compressive strengths, water
absorption capacity and resistance to abrasion. The laterite block samples will
be made from laterite clay sourced from Ogun state, Nigeria.
1.7 DEFINITION
OF KEY TERMS
ADOBE
- A Spanish word often used in
English (and French) to refer to a mud brick. This technique consists of
moulding laterite bricks without compaction and allowing them to dry in the
sun, hence their also being commonly known as laterite blocks.
CEMENT
- A mixture of limestone and clay
heated at a temperature of About 15000C after which gypsum would be added and
the resulting mix ground to a fine powder. It is indeed the addition of gypsum
that prolongs the setting of limestone and clay when in use.
COMPACTION
- This is a mechanical process aimed
at increasing the density of the material, thereby reducing porosity as well as
its characteristics. It also reduces its susceptibility to water.
COMPRESSED
LATERITE BRICKS - This
refers to the tampering of laterite in a mould where it is compressed using a
press.
GYPSUM
- This is a term used to refer to a
soft mineral called hydrated calcium sulphate which is the source of plaster of
Paris and other plasters. It is produced by heating gypsum rock to about 1700
C. At this temperature, about 75 percent of crystallization water would have
been driven off, leaving a white powder. This powdery substance gets hard after
mixing with water and settles over a short period of time.
HYDRATED
LIME - The
production of hydrated lime is carried out in two stages. The first stage
requires the calcination of limestone in a kiln at about 9000 C. At this stage,
carbon dioxide will be expelled and quick lime (calcium oxide) will be
produced. Second stage involves slaking or hydrating quick lime with a certain
volume of water which causes the production of hydrated lime (calcium
hydroxide).
LATERITE
- This is a term that is used to
refer to formation of soil, particularly clay and silt, by weathering of rocks
especially in a tropical climate, composed mainly of iron and aluminum
hydroxides. It is the term used to describe all the reddish residual and
non-residual tropically weathered soils formed from decomposed rocks through clays.
LIME
- This is a term used to refer to a
white caustic earth (calcium oxide, quicklime, caustic lime) which is got by
calcining calcium hydroxide (slaked lime) got by adding water to quicklime.
OPTIMAL
MOISTURE CONTENT - This
is defined as the moisture or water content at which a specified amount of
compaction would produce the maximum dry density.
SOIL
STABILISATION - This
is a term that refers to the process of obtaining a better quality soil by
improving the characteristics of the local soil in order to create a perfectly
suited material for construction works. It assists in reducing the volume of
the spaces between the solid particles thereby reducing its porosity.
STABILISERS
- These are complementary additions
of products intended to enhance the qualities of the earth materials further,
and above all, guarantee that the properties will endure over time. They are
also referred to as stabilizing agents.
STABILISED
LATERITE - Refers
to the mixture of sandy clay, water and a given quantity of stabilizing agents
such as lime, cement, bitumen emulsions etc. These stabilizers increase water
resistance. Mostly used for making walls, bricks etc.
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