ABSTRACT
The research was conducted to study the possibility of utilizing the waste
bricks abundantly available in most parts of Gwer-West Local Government Area of
Benue State, particularly Naka, the Local Government capital, as coarse aggregates
in structural concrete. Trial mixes were prepared using the crushed burnt bricks
known also as brick bats as coarse aggregates only, mixture of crushed bricks and
river washed gravel as well as using river washed gravel from River Benue only at
varying water-cement ratios. Cubes of concrete were prepared and tested to study
the compressive strength. The results indicate that the concrete having brick bats as
aggregates may be termed medium light weight concrete having a density between
2000-2200 kg/m3. Use of broken bricks as coarse aggregate for structural concrete
is recommended when natural aggregates are not easily available, high strength of
concrete is not required and the bearing capacity of the soil is low. Finally
Scheffe’s second degree polynomial was used to obtain a model for predicting the
compressive strength of gravel-crushed burnt bricks concrete.
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TABLE OF CONTENTS
Title page – – – – – – – – – – ii
Approval – – – – – – – – – – iii
Dedication – – – – – – – – – – iv
Acknowledgment – – – – – – – – – v
Table of Content – – – – – – – – – vii
List of Tables – – – – – – – – – x
List of Figures – – – – – – – – – x
Abstract – – – – – – – – – – xiii
Chapter One – – – – – – – – – 1
1.0 Introduction- – – – – – – – – 1
1.1 Research Background – – – – – – – 1
1.2 Research Problem – – – – – – – – 2
1.3 Significance – – – – – – – – – 2
1.4 Aim and Objectives – – – – – – – 3
1.5 Scope and Limitations- – – – – – – – 4
viii
Chapter Two – – – – – – – – – 5
2.0 Literature Review – – – – – – – – 5
2.1 Concrete- – – – – – – – – – 5
2.2 Cement – – – – – – – – – 6
2.3 Aggregates – – – – – – – – – 7
2.3.1 Classification of Aggregates – – – – – – 8
2.3.2 Crushed burnt bricks in Concrete – – – – – 9
2.4 Water cement ratio- – – – – – – – 11
2.5 Mix Design and Optimization – – – – – – 13
Chapter Three – – – – – – – – – 14
3.0 Materials and Methods – – – – – – – 14
3.1 Materials – – – – – – – – – 14
3.2 Methods – – – – – – – – 14
3.2.1 Sources of Data – – – – – – – – 14
3.2.2 Auxiliary Tests – – – – – – – – – 14
3.2.3 Concrete Mix Design – – – – – – – 15
ix
3.3 Model Derivation – – – – – – – – 15
Chapter Four – – – – – – – – – 23
4.0 Results, Model and Discussion – – – – – – 23
4.1 Specific Gravity (SG) – – – – – – 23
4.2 Aggregate Impact Value (AIV) – – – – – – 23
4.3 Aggregate Crushing Value (ACV) – – – – 24
4.4 Aggregate Water Absorption (AWA) – – – – – 24
4.5 Particle Size Distribution – – – – – – – 25
4.6 Slump – – – – – – – – – 28
4.7 Compressive Strength – – – – – – – 29
4.8 Model Verification- – – – – – – – 35
Chapter Five – – – – – – – – – 39
5.0 Conclusions and Recommendations – – – – – 39
5.1 Conclusions – – – – – – – – – 39
5.2 Recommendations – – – – – – – – 39
References – – – – – – – – – – 40
x
Appendix – – – – – – – – – – 45
CHAPTER ONE
1.0 INTRODUCTION
1.1 RESEARCH BACKGROUND
Concrete is a versatile engineering material consisting of cementing substance,
aggregates, water and often controlled amount of entrained air. It is initially a
plastic, workable mixture which can be moulded into a wide variety of shapes
when wet. The strength is developed from the hydration reaction between cement
and water. The products, mainly calcium silicates, calcium aluminates and calcium
hydroxide are relatively insoluble which bind the aggregate in a hardened matrix.
Concrete is considerably stronger in compression than in tension. For structures
required to carry only compressive loads such as massive gravity dams and heavy
foundations, reinforcement is not required and the concrete is consequently called
plain concrete. When the structure is to be subjected to tensile stresses, steel bars
are embedded in the concrete.
The requisite quantities of material for a given grade of concrete are usually
obtained from mix design. The constituent materials, when properly batched and
thoroughly mixed, set through the process of hydration and harden into a mass of
concrete capable of resisting compressive stresses. The extent to which a given
concrete resists the compressive stresses to which it is subjected depends largely
on the compressive strength of the concrete which in turn depends on the quality of
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the concrete. Since seventy five per cent of concrete is made up of aggregates, its
types, quality and general properties determine the quality of concrete (Neville,
1995, Troxel et al, 1968).
1.2 RESEARCH PROBLEM
Concrete is one of the most widely used construction materials. The raw
material from which it is prepared: cement, aggregates and water affect both the
quality and cost of construction. Aggregates are usually cheaper than cement and
constitute over 70% of the volume of concrete. The availability and proximity of
aggregate to the construction site also affect the cost of construction.
At present, the most commonly used coarse aggregates for concrete production
in Benue State of Nigeria is river washed gravel due mainly to the presence of
River Benue and its deposits. But these are not readily available in some local
government areas which are not serviced by the river. Thus the cost of transporting
gravel to the areas outside the catchment of the river tends to increase the cost of
construction even at relatively low labour. This necessitates the use of alternative
coarse aggregates which are locally obtained. One such coarse aggregate is crushed
burnt bricks obtained from the production of burnt bricks (Maher, 1987).
1.3 SIGNIFICANCE
In many countries, the need for locally manufactured building materials can
hardly be overemphasized because there is an imbalance between the demands for
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housing and expensive conventional building materials coupled with the depletion
of traditional building materials. To address this situation, attention has been
focused on low – cost alternative building materials (Agbede and Manasseh, 2008
and Waziri et al, 2011).
This research is therefore important as it tries to compare the compressive
strength of concrete made with the conventional gravel and crushed burnt bricks as
coarse aggregates.
1.4 AIM AND OBJECTIVES
This research is aimed at finding out whether crushed burnt bricks can be
substituted for gravel as coarse aggregates in the production of concrete. The
objectives include:
i. To determine the compressive strength of concrete with gravel and crushed
burnt bricks or brick bats as coarse aggregates.
ii. To determine the optimum mix ratio.
iii. To compare the compressive strength of concrete with gravel and crushed
burnt bricks as coarse aggregates.
iv. To determine the effect of partial substitution of gravel with crushed burnt
bricks as coarse aggregates on the compressive strength of concrete.
v. To develop a model for predicting the compressive strength of gravelcrushed
burnt brick concrete.
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1.5 SCOPE AND LIMITATIONS
This research is carried out on crushed burnt bricks produced from Naka,
Benue State and river washed gravel from River Benue as coarse aggregates. The
investigation is limited to the workability and compressive strengths of concrete
cubes made from different mixes of sand, gravel and/or crushed burnt bricks,
Benue Cement and water. The study does not cover the temperature at which burnt
bricks will give optimum strength; neither does it cover the effect of admixtures on
the compressive strength of crushed burnt bricks-concrete.
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