ABSTRACT
High cost of cement has caused serious impact on housing delivery due to increase in
energy costs and high demand which attracted many research interests in sourcing other
alternatives cheaper materials. The use of rice husk powder in composites cement system
was investigated. Paste of neat and blended Portland cement with 5%, 10%. 15%, 20%,
25%, 30%, 35%, 40%, 45%, 50%, and 55% rice husk powder were cured in air under the
same temperature and humidity condition. Compressive strength of the various mix
proportions at 28 days were determined using standard compressive strengths testing
machine. The hydration products of the high percentage replacement composite cement
pastes were identified by x-ray diffraction analysis and compared with those made from
100% ordinary Portland cement pastes. Results indicate that only lower percentage
replacement level such as 5% and10% rice husk powder contained the required amounts
of silica which aided the hydration process producing samples with compressive
strengths of 19.72N/mm2 and11.57N/mm2when compared with control sample with
33.33N/mm2. However, result of the x-ray diffraction analysis showed that the observed
hydration products were mostly as expected due to the high replacement levels but the
degree to which crystal phases were identified in one of the samples was unusual. The
unusual behavior may be due to the fact that the calcium hydroxide initially formed was
consumed during the curing period confirming the important pozzolanic reactions of the
rice husk powder at such high replacement.
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TABLE OF CONTENTS
CHAPTER 1: INTRODUCTION …………………………………………………………………………. 1
Statement of the Problem ……………………………………………………………………………………. 2
Aim of the Research ………………………………………………………………………………………….. 3
Objectives ………………………………………………………………………………………………………… 3
Scope ……………………………………………………………………………………………………………………….. 3
Significance of the Research ……………………………………………………………………………….. 3
Delimitation of the Study. …………………………………………………………………………………… 3
Limitation of the Study. ……………………………………………………………………………………… 4
Research Questions/Hypothesis …………………………………………………………………………… 4
Basic Assumptions ……………………………………………………………………………………………. 4
CHAPTER 2: LITERATURE REVIEW ……………………………………………………………….. 5
Origin of Cement ………………………………………………………………………………………………. 5
Ceramics and Glasses ………………………………………………………………………………………… 6
Ordinary Portland Cements …………………………………………………………………………………. 7
Difference Types of Portland cements…………………………………………………………………… 8
The Manufacture of Ordinary Portland Cements ………………………………………………………… .9
Hydration of Portland Cements …………………………………………………………………………. 10
Composite Cement System ……………………………………………………………………………….. 11
Pozzolana ………………………………………………………………………………………………………. 12
Rice Husk ………………………………………………………………………………………………………. 13
Mixing Methods for Concrete ……………………………………………………………………………. 14
Types of Mixers ………………………………………………………………………………………………. 15
Curing Condition …………………………………………………………………………………………….. 15
Microstructural Analysis …………………………………………………………………………………… 16
Compressive Strengths……………………………………………………………………………………… 16
X-Ray Diffraction (XRD) …………………………………………………………………………………. 17
Crystal Structure and Chemical bonds…………………………………………………………………. 19
Relevant Works on Rice Husk-OPC Composites. …………………………………………………. 19
CHAPTER 3: MATERIALS AND METHODS …………………………………………………… 22
Materials and Methods ……………………………………………………………………………………… 22
Preparation of Rice husk powder ……………………………………………………………………… 22
Production of Specemens ………………………………………………………………………………….. 23
Casting and Compacting of the Concrete …………………………………………………………….. 23
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Compressive Strength Test ……………………………………………………………………………….. 25
X-Ray Diffraction Analysis ………………………………………………………………………………. 26
CHAPTER 4: RESULTS AND DISCUSSION …………………………………………………….. 28
Results of Compressive Strength Test …………………………………………………………………. 28
Results of X-Ray Diffraction Analysis ………………………………………………………………… 29
Discussions …………………………………………………………………………………………………….. 31
Compressive Strength ………………………………………………………………………………………. 31
X-Ray Diffraction Analysis (X.R.D) …………………………………………………………………… 31
CHAPTER 5: SUMMARY,CONCLUSION AND RECOMMENDATION ……………….. 33
Summary ……………………………………………………………………………………………………….. 33
Conclusion……………………………………………………………………………………………………… 33
Recommendation …………………………………………………………………………………………….. 33
REFERENCES ……………………………………………………………………………………………….. 35
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LIST OF TABLES
Table
3.1 Design …………………………………………………………………………………………………………. 24
4.1Compressive Strength of Rice Husk Cement Samples …………………………………………… 28
4.2 Observed Crystals (phases) in the X-Ray Diffraction Spectrum Peak ……………………… 29
4.3 Corresponding Lattice Parameters of the Crystals (Phases) ………………………………….. 30
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CHAPTER ONE
1.0 Introduction
Portland cement is the essential binding agent in cement composite systems, which in turn
is the most commonly used construction material worldwide due to its many advantages
including lower relative price, durability and other properties. (Escalante and
Sharp,2004). Its cost is increasing due to the increase in energy cost and high demand of
the product. However, to meet this demand other alternative cheaper materials are being
sourced. (Escalante and Sharp,2004 ).
Materials of natural origin such as volcanic ash (VA) or industrial by product, like
granulated blast furnace slag (GBFS) and pulverized fuel ash (PFA) have been widely
used as partial replacement of Portland cement in concrete construction (Escalante and
Sharp, 2004). Similarly, an agricultural waste rice husk has been described as a pozzolana
with promising cementing properties when used with Portland cement. (Amjad and
Abdul, 2004).
The advantages of these replacement materials are improved technical properties, lower
cost and a reduction of waste accumulation. For instance, replacement of 5% of the
aforementioned materials can provide a decrease of about 75×106 tons of CO2. (Escalante
and Sharp, 2004).
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The idea of adding pozzolana to Portland cement or Portland cement concrete is widely
practiced because it does not only reduce cost and conserves energy, but decreases the
heat of hydration, increases compressive strength and durability. (Amjad and Abdul,
2004).
The introduction of replacement materials in Portland cement produces additional
complexity to the chemical reactions developed during hydration of the composite
cements. (Escalante and Sharp, 2004). It has been observed that both latent hydraulic and
pozzolanic materials participate in the overall hydration process and in the development
of microstructure. The dominant product of these reactions is C – S – H gel, which is
principally responsible for the mechanical properties of the hydrated cement. C – S – H
gel is generated by the interaction of the replacement materials with Portlandite (CH),
liberated during the hydration of the alite and belite present in the cement (Escalante and
Sharp, 2004).It is evident from many studies that variation in curing condition affects
pozzolanic reactivity of the composite cement. (Amjad and Abdul, 2004). However, little
or no attention has been paid to investigate how composite cement systems react at
fluctuating weather conditions of Zaria.
1.1 Statement of the Problem
Cement consumption is generally considered as an indicator of the growth of the Gross
National product (GNP) of a country. In Nigeria, it is estimated that the demand for
cement is about 18 million tones annually used mainly in the construction and building
industries. (Dadu,2008). While local production for the past 10 years is between 2.5 to
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6.5 million tones annually. However, to meet this demand an alternative and cheaper
material is desirable.
Rice-husk, a pozzolanic materials and agricultural waste are land filled and burnt in open
piles which is not environmentally friendly. An easy and efficient way of utilizing this
waste is by using it with cement to serve the construction and building industries.
1.2 Aim of the Research
The study aims at investigating the compressive strength and identifying the crystal
phases of the composites.
1.3 Objectives
1. Determining the compressive strength of the composite by using standard compressive
strength testing machine.
2. Identifying the crystal phases of the hydration products by x-ray diffraction analysis.
1.4 Scope
The scope of the study embraces the crystal phase identification of the composite cement
and the determination of its compressive strength.
1.5 Significance of the Research
The result obtained from this research will advance and possibly open new frontiers of
knowledge in the production of cement composites by utilizing local raw materials. If
implemented, it would amount to saving cost on procurement of construction materials
like cement and also will help in controlling environmental problems that are associated
with the
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burning of waste in rice production.
1.6 Delimitation of the Study
The investigation is delimited to production of composites from mixture of ordinary
Portland cement with rice husk powder.
1.7 Limitation of the Study
Some of the problems encountered in carrying out the study were lack of some research
facilities like;
1. Differential Thermal Analyzer: For examining the heat change during hydration
of the cement paste.
2. Scanning Electron Microscope: This is useful in the study and characterization of
the composite.
1.8 Research Question/Hypothesis
1. What are the crystalline phases of the composites and their relative proportion?
2. What are the measures of the compressive strength of the composites?
1.9 Basic Assumptions
a. That the crystalline phases and their relative proportions would comply with the
International Centre for Diffraction Data (ICDD) standards.
b. That the compressive strength achievable through mixing method would yield
satisfactory results.
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