MODIFICATION AND CHARACTERIZATION OF THE

NIGERIA NATURAL BITUMEN

BY

AKINRINSA, SAMUEL DAMILARE

(162237)

PROJECT REPORT SUBMITTED TO

DEPARTMENT OF CHEMICAL ENGINEERING,

FACULTY OF ENGINEERING AND TECHNOLOGY,
LADOKE AKINTOLA UNIVERSITY OF TECHNOLOGY.
OGBOMOSO, OYO STATE, NIGERIA

IN PARTIAL FULFILMENT OF THE REQUIREMENTS

FOR THE AWARD OF DEGREE OF BACHELOR OF
TECHNOLOGY (B. TECH) IN CHEMICAL
ENGINEERING

JUNE 2023
 CERTIFICATION
This is to certify that this project report on “Modification and

Characterization of the Nigeria Natural Bitumen” submitted by AKINRINSA,

SAMUEL DAMILARE (Matric Number: 162237), was carried out at the Department

of Chemical Engineering, Faculty of Engineering and Technology, Ladoke Akintola

University of Technology, Ogbomosho.

__________________________ ______________________

Supervisor Date

Dr. AArinkoola, B.Tech, M.Sc., Ph.D.

Associate Professor

Department of Chemical Engineering

Ladoke Akintola University of Technology

Ogbomoso, Nigeria.

ii
 ATTESTATION
I hereby attest that this research was carried out in the Department of Chemical

Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.

__________________________ ______________________

Ag. Head of Department Date

Dr. Ajayi, B.Tech, M.Sc., Ph.D.

Associate Professor

Department of Chemical Engineering

Ladoke Akintola University of Technology

Ogbomoso, Nigeria.

iii
 DEDICATION
This project report is dedicated to Almighty God the uncreated creator of all

creations. Also, to my loving parent Elder Rufus Akinrinsa and Deaconess Janet

Akinrinsa for their tireless effort towards my education.

iv
 ACKNOWLEDGEMENTS
My gratitude goes to God Almighty for His enduring grace and mercies,

provision and wisdom in the course of this research. I would like to extend my deepest

appreciation to my project supervisor, Professor T.O. Salawudeen and co-supervisors;

Dr. A.O. Arinkoola, Dr. K. K. Salam and Dr Mrs. Jimoh, for their unwavering support

and expert guidance. Their valuable insights, constructive feedback, and continuous

encouragement have played a significant role in shaping this project. May the good God

bless you.

I would also like to thank my ever-capable Head of Department, Dr. Mrs. Ajani,

for her support and word of encouragement since she has been appointed as the Head of

the Department. Thank you and God bless you. To all Chemical Engineering lecturers

and staff, I say a very big thank you for your valuable input and suggestions. Your

knowledge and expertise have greatly contributed to the quality and depth of this

project.

I would like to acknowledge the help and cooperation of my project mates

specifically Adediji Quadri and my fellow research assistant Akanji Saheed Ayobami,

for providing the necessary resources and assistance throughout the project. Their

cooperation and willingness to share their knowledge have been instrumental in the

successful completion of this endeavor.

I am grateful to my parents (Elder Rufus Akinrinsa and Deaconess Janet

Akinrinsa), my siblings (Akinrinsa David, Akinrinsa Timileyin, Akinrinsa Damilola)

and my friends (Oyelade Aduragbemi, Omotoye Oluwatosin, Ajakaye Oluwatobiloba,

Samson Michael) for their constant encouragement and support. Their belief in me has

v
been a constant source of motivation, and I am truly thankful for their presence in my

life.

Lastly, I would like to thank all those individuals who have directly or indirectly

contributed to this project but may not be mentioned explicitly. Your support and

encouragement have been invaluable, and I deeply appreciate your contribution.

vi
 ABSTRACT
Bitumen is a material used in many engineering applications, especially in

flexible highway pavements and due to its viscoelastic and thermoplastic properties,

bitumen behaves like an elastic solid at low temperatures or under rapid loading and

like a viscous fluid at high temperatures or under slow loading. Previous research on

Nigeria's natural bitumen deposits has revealed that many of the deposits are great

construction materials, while others that aren't so good in their original state can be

modified to provide suitable road construction materials. This research investigated the

modification and characterization of Nigeria natural bitumen for different applications.

Bitumen was obtained from four different locations; Agbabu (5°45 ‘N and 7°00

‘E), Loda (6°65 ‘N and 4°88 ‘E), Abigi (6°68 ‘N and 4°31 ‘E), Sunbare (6°71 ‘N and

4°36 ‘E). Only bitumen obtained from Agbabu was pure because it was drawn from a

well while the other samples were tar sands. The solvent extraction technique was used

to extract bitumen from the tar sand using petroleum ether. The modification process

was done by first fluidizing the bitumen to about 120 °C and then adding the polymer

(polypropylene) to it and mixing at a rate of 1200 rpm for 1 hr till it reaches a

temperature of about 160 – 170 °C. The raw bitumen and modified samples were

characterized using EDX, SEM, TG curve and FTIR to determine their elemental

composition, morphological characterization, thermal stability and functional group of

their compound. Rheological test was also carried out to know the penetration point of

the raw and modified bitumen.

The EDX analysis for the raw bitumen showed that Abigi and Sunbare have

more metal composition than that of the Loda and Agbabu sample but carbon has the

highest weight percent in all the four sample. The TG curve showed that Loda raw

bitumen has the highest thermal stability because its losses lesser weight during the test.

vii
The penetration test showed that Loda sample in its unmodified state has the lowest

penetration point (51.24 mm) when compare to the rest. And from the penetration test

that was done for the Agbabu raw and modified bitumen, it was observed that

modifying Agbabu bitumen with polypropylene decreases its penetration point from

51.27 mm to 40.50 mm.

From the four samples, only Agbabu sample has been really worked upon, but

from this research work, it could be seen that Loda sample has more thermal stability

and better penetration point when compare to the other. Using more materials for its

modification will enhance better characteristics of this sample.

viii
 TABLE OF CONTENTS
Contents Pages

Title page i

CERTIFICATION ii

ATTESTATION iii

DEDICATION iv

ACKNOWLEDGEMENTS v

ABSTRACT vii

TABLE OF CONTENTS ix

LIST OF TABLES xiii

LIST OF FIGURES xiv

LIST OF PLATES xv

LIST OF ABBREVIATIONS xvi

CHAPTER ONE 1

INTRODUCTION 1

1.1 Background of Study 1

1.2 Statement of the Problem 2

1.3 Justification 3

1.4 Aim and Objectives 3

1.5 Scope of Study 4

CHAPTER TWO 5

LITERATURE REVIEW 5

2.1 Tar Sand 5

2.1.1 Properties of Nigeria Tar Sand 8

2.2 History of Bitumen 8

ix
2.3 The Nigeria Bitumen 12

2.4 Bitumen Sources 13

2.4.1 Mineral pitch 13

2.4.2 Petroleum pitch 13

2.5 Uses of Bitumen 13

2.5.1 Agriculture 13

2.5.2 Buildings and industrial paving 14

2.5.3 Hydraulics and erosion control 14

2.5.4 Industrial 14

2.5.5 Railways 14

2.5.6 Recreation 15

2.6 Composition of Bitumen 15

2.6.1 Asphaltene 15

2.6.2 Malthenes (also called petrolenes) 16

2.7 Properties of Bitumen 17

2.7.1 Adhesion 17

2.7.2 Resistance to water 17

2.7.3 Hardness 17

2.7.4 Viscosity and flow 18

2.7.5 Softening point 18

2.7.6 Ductility 19

2.7.7 Specific gravity 19

2.7.8 Durability 19

2.7.9 Versatility 19

2.7.10 Strength 19

x
2.8 Bitumen Modification 20

2.9 Polymer Modification of Bitumen 23

CHAPTER THREE 26

RESEARCH METHODOLOGY 26

3.1 Materials 26

3.2 Equipment and Apparatus 26

3.3 Reagents 26

3.4 Instruments 26

3.5 Methods 29

3.5.1 Sample Procurement and Location 29

3.5.2 Extraction and Purification of Bitumen from Tar Sand 32

3.6 Procedure for physical and mechanical test for the bitumen samples 34

3.6.1 Procedure for Viscosity 34

3.6.2 Procedure for Softening Point 34

3.6.3 Procedure for Ductility Test 35

3.6.4 Procedure for Penetration Test 36

3.6.5 Determination of Flash Point 38

3.6.6 Determination of Cloud Point 38

3.6.6 Determination of the Pour Point of the Bitumen 39

3.7 Characterization of the Nigeria Natural bitumen 39

3.7.1 Thermogravimetric Analysis (TGA) 39

3.7.2 Fourier Transform Infrared (FTIR) Spectroscopy 39

3.7.3 Differential scanning calorimetry (DSC) 40

3.7.4 SEM (Scanning Electron Microscopy). 40

3.7.5 Conventional physical test methods 40

xi
3.8 Modification of the Bitumen 41

3.9 Experimental design for bitumen modification 44

CHAPTER FOUR 46

RESULTS AND DISCUSSION 46

4.1 Energy-Dispersive X-ray (EDX) 46

4.2 SEM (Scanning Electron Microscopy). 60

4.3 Thermogravimetric Analysis (TGA) 62

4.4 Fourier Transfer Infrared (FTIR) spectroscopy 66

4.5 Differential scanning calorimetry (DSC) 80

4.6 Penetration Test of Agbabu Natural Bitumen Modified with Polypropylene

82

4.7 Physical and mechanical tests for Agbabu Natural Bitumen (ANB) modified

with butyl acrylate (BA) and poly(styrene-co-butadiene) (PSCB) 85

CHAPTER FIVE 90

CONCLUSIONS AND RECOMMENDATIONS 90

5.1 Conclusions 90

5.2 Recommendation 90

REFERENCES 92

xii
 LIST OF TABLES
Tables Titles Pages
2. 1 Oil composition of Nigeria tar sand 9
2. 2 Chemical composition of Nigeria tar sand. 10
2. 3 Metal composition of Nigeria tar sand 11
2. 4 The common types of modifiers are listed below 22

3. 1 Equipment and their function 27

4. 1 Elemental composition of Agbabu natural bitumen 47

4. 2 Elemental composition of Loda bitumen 50
4. 3 Elemental composition of Abigi bitumen 53
4. 4 Elemental composition of Sunbare bitumen 56
4. 5 Elemental composition of investigated four bitumen samples. 59
4. 6 Decomposition Temperature 65
4. 7 Infrared Absorption Peaks of Purified ANB 68
4. 8 Infrared Absorption Peaks of Purified Sunbare Natural Bitumen 71
4. 9 Infrared Absorption Peaks of Purified Loda Natural Bitumen 74
4. 10 Infrared Absorption Peaks of Purified Abigi Natural Bitumen 77
4. 11 Penetration test for the saw samples 83
4. 12 Penetration test for polymer (Polypropylene) modified Agbabu
Bitumen 84
4. 13 Agbabu Bitumen Modified with Butyl Acrylate 86
4. 14 Agbabu Bitumen Modified with Poly(styrene-co-butadiene) 87

xiii
 LIST OF FIGURES
Figures Titles pages
3. 1 The workflow for the research 45

4. 1 Graphical Representation of Elemental composition of Agbabu natural

bitumen 48
4. 2 Graphical Representation of Elemental composition of Loda bitumen 51
4. 3 Graphical Representation of Elemental composition of Abigi bitumen 54
4. 4 Graphical Representation of Elemental composition of Abigi bitumen 57
4. 5 Thermogravimetric Analysis of the Nigeria Natural Bitumen 64
4. 6 Fourier Transform Infrared Spectrocopy of Agbabu Natural Bitumen 67
4. 7 Fourier Transform Infrared Spectrocopy of Sunbare Natural Bitumen 70
4. 8 Fourier Transform Infrared Spectrocopy of Loda Natural Bitumen 73
4. 9 Fourier Transform Infrared Spectrocopy of Abigi Natural Bitumen 76
4. 10 Fourier Transform Infrared Spectrocopy of the four Natural Bitumen
Location 79
4. 11 DSC analysis of four bitumen samples 81

xiv
 LIST OF PLATES
Plates Titles Pages
2. 1 Pictorial Representation of Tar sand deposit 6
2. 2 Tar Sand 7

3.1 Petroleum Ether bottle sample 28

3. 2 Loda tar sand sample deposit 30
3. 3 Abigi tar sand sample deposit 30
3. 4 Sunbare tar sand sample 31
3. 5 Purification Process of Bitumen 33
3. 6 Modification Process of Bitumen 43
3. 7 SEM Images of natural bitumen samples obtained from (a) Abigi, (b)
Loda, (c) Agbabu and (d) Sunbare. 61

xv
 LIST OF ABBREVIATIONS

TGA Thermogravimetric Analysis

SEM Scanning Electron Microscopy
FTIR Fourier Transform Infrared
DSC Differential Scanning Calorimeter
EDX Energy Dispersive X-ray
ANB Agbabu Natural Bitumen
PSCB Poly(styrene-co-butadiene)
BA Butyl Acrylate
PP Polypropylene

xvi
 CHAPTER ONE

INTRODUCTION
1.1 Background of Study

Bitumen is a petroleum liquid or semiliquid that is sticky, black, and highly

viscous. It is a pitch-like substance that can be found in natural deposits or as a refined

product. It has an API viscosity of 8° to 10°. It has a density of 1.0 to 1.18 kg/m 3, is

insoluble in water, has a boiling point of more than 300 °C, a melting point of 54-173
(Alhassan et al., 2020)
°C, and a flash point of more than 200 °C . Bitumen is a largely

insoluble adhesive and waterproofing material generated from crude oil or found in

natural asphalt that is totally or nearly completely soluble in toluene and viscous or

nearly solid at ambient temperatures.

It is widely known that bitumen's original characteristics, as well as bitumen

crude oil characteristics, are significantly dependent on its production and processing

procedures. Bitumen characteristics can be improved using good crude oils and

adequate distillation methods. Bitumen yields are often higher with heavier crude oil.

As a result, having

a thorough understanding of bitumen qualities from several perspectives is

critical. This knowledge becomes even more crucial when challenges in the production

and use of bituminous materials, such as phase discontinuities, mal-dispersion, and

instability with polymers/additives, make it difficult to produce and apply bituminous

(Porto et al., 2019)
materials. .

Bitumen is one of the earliest engineering materials known to mankind. It has

been used for thousands of years as a sealant, preservative, and pavement binder, among

other things. Refined bitumen was first manufactured in the United States in the early

1900s by refining crude oil. Since then, global bitumen usage has risen quickly, with the

1
majority of it being utilized in road construction. Global bitumen consumption is

currently over 102 million tonnes per year, with 85 percent of that used in various types
(Zhu et al., 2014)
of pavements .

Nigeria is ranked 6th (in a list of top 10 countries) in bitumen (and heavy oil)

deposits, followed by Madagascar, the United Kingdom, China, and Azerbaijan, with

Canada, Venezuela, Kazakhstan, Russia, and the United States taking the lead. Nigeria

is the second-largest country with bitumen deposits, after Venezuela, with an

approximated reserve of 42 billion barrels of oil found in cretaceous ferruginous

sediments extending over about 120km from Ogun state, across Ondo state to the

margin of Edo state. Bitumen can be refined into commercial products such as gasoline,

fuel oil, and asphalt after being turned to liquid. Bitumen is found in large amounts

worldwide but in exceptionally large quantities in Canada and Venezuela

(Zhu et al., 2014)
.

The most well-known location of bitumen activity in the belt is Ondo State,

which has offices of the Nigerian Bitumen Development Project in Akure and Ore.

Outcrop, rich sands, lean sands, shales, and heavy crudes have all been recognized as

various bitumen-impregnated hydrocarbon types of occurrences within the Nigerian

bitumen belt, from topsoil downwards from location to site. Nigerian tar sand has a

bitumen concentration of roughly 20% by weight on average. The regions of Idiobilayo,

Foriku, Agbabu, Okitipupa, and Aiyibi in Ondo State have very rich natural bitumen

reserves. Bitumen, water, and various mineral impurities make up tar sands in general.

Tar sands classified as good or medium quality contain 5–10 percent bitumen by
(Alhassan et al., 2020)
weight. .

2
1.2 Statement of the Problem

Previous research on Nigeria's natural bitumen deposits has revealed that many

of the deposits are great construction materials, while others that aren't so good in their

original state can be modified to provide suitable road construction materials. This

research will be undertaken on the materials in order to properly characterize them and
(Munera et al., 2014)
develop construction specifications . In most parts of the world,

packaging constitutes as much as one-third of the nonindustrial waste stream and the

recycling rate is still very low. In this sense, the use of waste packaging plastics for

replacing virgin polymers as a modifier is a worthy concept, which may result in greater
(Zhu et al., 2014)
cost savings .

Bitumen can be used in a number of areas besides road works. The possibility of

using the natural bitumen in the other areas would be examined.

1.3 Justification

Bitumen possesses adequate performance characteristics, but increasing the high

temperature performance can sometimes lessen the low temperature performance

(Wang et al., 2019)
properties of the bitumen . This research will help to counter this

effect with the use of polymeric and nano materials which are cost effective and readily

available. Also, this research work needs to be carried out as soon as possible so that the

Nigeria natural bitumen lying in waste can be explore, modified and characterized for

adequate use.

1.4 Aim and Objectives

The aim of this study is to evaluate the modification and characterization of

Nigeria natural bitumen. To achieve this aim, the following objectives would be taken

into consideration:

3
 i. Procurement and location of bitumen and Tar sand from different area (Agbabu,

Abigi, Sunbare and Loda) in Nigeria for SEM, EDX, FTIR and TG analysis.

ii. Purification of Nigeria bitumen and Tar sand using solvent techniques method and

rheological characterization

iii. Polymeric modification of the Nigeria bitumen and characterization

1.5 Scope of Study

This research is limited to the use of bitumen collected in Agbabu, Sunbare,

Loda and Abigi. The method of extraction of bitumen from the Nigeria tar sand is the

solvent extraction techniques. The modifiers used are Butyl Acrylate, Polypropylene

(PP), Ethylene-Vinyl-Acetate (EVA), Poly(styrene-co-butadiene), Polyethylene and

nano materials.

4
 CHAPTER TWO

LITERATURE REVIEW
2.1 Tar Sand

Tar sand is made up of a mixture of bitumen (approximately 10-20 percent

bitumen) and mineral matter (sands, clays, and 4-6 % water). Tar sand is comparable to

light crude in composition. Due to a lack of cap rock, they are thought to have

originated via biodegradation and water-washing of light crude. A similar technique is

said to have produced the Nigerian Tar Sand. Tar sands are impregnated sands that

create liquid hydrocarbon mixes that require additional processing beyond mechanical

blending to become final petroleum products. Nigerian bitumen deposits were

previously known as tar sands, but are now recognized as oil sands. Oil sands are

deposits of bitumen, a sticky oil that must be treated rigorously before it can be refined
(Spirov et al., 2013)
into gasoline, kerosene, and other fuels .

Bitumen makes up around 20% of the oil sands in Nigeria, with mineral matter

accounting for 76% of the total, including clay and sand, and water accounting for 4%.

Tar sand is a sedimentary rock that includes bitumen or other heavy petroleum that

cannot be collected using traditional petroleum-recovery methods in its natural state.

This is usually true for oils with a gravity of less than 12 °API. The largest world

deposits are in Canada, Venezuela, Madagascar, USA, and Russia.Because of its high
(Akinyemi et al., 2013)
viscosity, recovering bitumen from tar sand is a tough task. .

Tar sands are sedimentary rocks (consolidated or unconsolidated) containing

bitumen (solid or semisolid hydrocarbons) or other heavy petroleum that cannot be

collected using standard petroleum recovery technologies in their natural condition.

5
Plate 2.1 shows a pictorial representation of tar sand deposit while Plate 2.2 show a

typical tar sand.

Plate 2. 1 Pictorial Representation of Tar sand deposit

Source: Schindler et al., 2010

6
Plate 2. 2 Tar Sand
Source:
https://response.restoration.noaa.gov/sites/default/files/images/13/
bitumen-tar-sands_govt-alberta-canada.jpg)

7
 Technically, tar sand is not a mixture of tar and sand, as the name suggests,

because tar is a viscous liquid with adhesive qualities that is obtained by destructive

distillation of coal, wood, shale, and other materials, and such an origin for tar in tar
(Ogiriki, et al., 2018)
sands is rarely mentioned. .

2.1.1 Properties of Nigeria Tar Sand

Oil sand (tar sand) consists of an initiate mixture of bitumen, water, quart sand
(Porto et al., 2019)
and clays and other minerals which is either oil or water wet. . Table

2.1, Table 2.2 and Table 2.3 shows the oil, chemical and metal composition of the

Nigeria natural bitumen.

2.2 History of Bitumen

The Sumerians called it esir, the Akkadians called it iddu, and the Arabs of Iraq

called it sayali, zift, or qar, it is more commonly known in English as "bitumen" or

"asphalt"—that thick, dark liquid that you immediately associate with the smell of

freshly laid pavement and which was the first petroleum product ever used by humans

(Zayn Bilkadi, 2006).

Bitumen was widely employed by the Sumerians, Assyrians, and many other

ancient civilizations. The discovery of bituminous stones in France in 1712 marked the

beginning of the current bitumen industry. At the time, bitumen was simply spread as a

clod on the surface of local roads, and it was rubbed and cemented under heavy traffic.

This technique was very successful, and soon after, improvements such as powdering

and warming the material before use were made. The asphalt was then tightened and

cemented by slamming and flattening it, resulting in compressed rock asphalt, which

was utilized on European streets. Such streets were more durable, healthier, more
(Porto et al., 2019)
intriguing than earthy roads .

8
 Table 2. 1 Oil composition of Nigeria tar sand

Element Composition(%)

Water 5

Bitumen 10

Sand particles 70

Fines (clay-minerals) 15

Source: (Porto et al., 2019)

9
 Table 2. 2 Chemical composition of Nigeria tar sand.

Element Composition (%)

Carbon 85

Hydrogen 10.7

Nitrogen 0.5

Oxygen 1.7

Source: (Porto et al., 2019)

10
 Table 2. 3 Metal composition of Nigeria tar sand

Element Composition (ppm)

Vanadium 35

Nickel 33

Source: (Porto et al., 2019)

11
 The only disadvantage was that they were flimsy, volatile, and slick under high

traffic. In 1843, the first bitumen reformation took place. In Europe, bitumen refinement

project experiments began in the 1930s, and in North America, the use of Neoprene

Latex as a bitumen modifier began in the 1950s. In order to better understand the

behavior of modified bitumen with various types of natural and synthetic rubbers, the

first experimental modified bitumen roads were built in France in 1963

(Honarmand et al., 2019)
.

In the late 1970s, Europe outperformed the United States when it came to

bitumen refining. One of the reasons was the requirement that European contractors

provide a guarantee for the pavement's durability and shelf life, which would have

reduced the cost of the road's lifespan while increasing initial costs. In the United States,

the relatively high initial cost of performing rehabilitated asphalt had limited its use.

New polymers introduced by European technology in the mid-1980s enhanced

(Honarmand et al., 2019)
polymeric bitumen consumption in the United States. .

2.3 The Nigeria Bitumen

Bitumen was discovered first in Nigeria around the 1900s, with its exploration
(Christina Milos, 2015)
beginning particularly in 1905 . Bitumen is one of the richly

deposited mineral resources in Nigeria, just like crude oil, it is found in Ondo, Lagos,

Ogun, and Edo State. In Ondo State, where a larger deposit of bitumen is, the state

government is advocating on behalf of its people for the exploration of this mineral in

the state. From the government's view, its development can help reduce the

environmental degradation which is caused by the spilling of the bitumen on the

farmlands and rivers, and as well will create not only employment for the people of the

state and the nation at large but will also lure prominent local and international investors
(Adedimila, 2004)
.
12
 In as much as the mineral resources can richly serve as an alternative to crude oil

which has declined over the years, it is good to know also about the implications

involved in the mining as it can lead to deforestation and likely affect most parts of Irele

Local Government Area of Ondo State, where the bitumen deposits occur in huge

quantity. This location is recorded as the largest deposit of bitumen in Africa and the

second-largest deposit in the world. Recently, a technical and economic evaluation of

Bitumen in the southwestern region of Nigeria was conducted, and it was observed that

it contains oil which accounts for more than 13 to 16 billion barrels of oil
(Ogiriki, et al., 2018)
.

2.4 Bitumen Sources

2.4.1 Mineral pitch

Natural bitumen is the dark substance that remains when volatile crude oil

components are evaporated in the earth's interior over time and under conditions like

high temperature and pressure. This kind of pitch is typically a blend of bitumen and
(Honarmand et al., 2019)
mineral elements and is not always pure .

2.4.2 Petroleum pitch

Crude oil is refined in distillation towers to produce oil pitch. In actuality, pure

oil pitch is what is left at the bottom of the distillation tower over 380°C. By adjusting

the temperature and pressure inside the distillation tower, bitumen with various degrees
(Honarmand et al., 2019)
of stiffness for various road applications can be produced. .

2.5 Uses of Bitumen

2.5.1 Agriculture
Disinfectants, fence post coating, mulches, mulching paper, paved barn floors,

barnyards, feed platforms, Protecting tanks, vats protection for concrete structures, tree
(Shaqe, 2015)
paints (protective) .

13
2.5.2 Buildings and industrial paving
Water and moisture barriers (above and below ground),floor compositions, tiles,

coverings, insulating fabrics, papers Step treads, building papers, caulking compounds,

cement waterproofing compounds, glass wool compositions, insulating fabrics, felts,

papers, joint filler compounds, laminated roofing shingles, liquid roof coatings, plastic

cements, shingles, acoustical blocks, compositions, damp-proofing coatings, insulating

board, fabrics, masonry coatings, plaster boards, putty, sound proofing, stucco base,

wallboard, air-drying paints, varnishes, Artificial timber, ebonised timber, Insulating

(Shaqe, 2015)
paints, plumbing, pipes, treated awnings, Canal linings, sealants .

2.5.3 Hydraulics and erosion control

Catchment areas, basins, dam groutings, dam linings, protection, dyke

protection, ditch linings, drainage gutters, structures, embankment protection groynes,

jetties, levee protection, mattresses for levee and bank protection, membrane linings,

waterproofing, reservoir linings, revetments, sand dune stabilization, sewage lagoons,

oxidation ponds, swimming pools, waste ponds, water barriers, backed felts
(Shaqe, 2015)
.

2.5.4 Industrial
Conduit insulation, lamination Insulating boards, paint compositions, pipe

wrapping, panel boards, underseal, battery boxes, carbons, electrical insulating

compounds, tapes, wire coatings, junction box compound, Moulded conduits, black

grease, buffing compounds, cable splicing compound, embalming, etching

compositions, extenders, explosives, lap cement, plasticizers, preservatives

(Shaqe, 2015)
.

14
2.5.5 Railways
Ballast treatment, dust laying, paved ballast, sub-ballast, paved crossings, freight
(Shaqe, 2015)
yards, station platforms .

2.5.6 Recreation
Dance pavilions, drive-in movies, gymnasiums, sport arenas, playgrounds,

school yards, race tracks, running tracks, skating rinks, swimming and wading pools,

tennis courts, handball courts, synthetic playing fields and running track surfaces.
(Shaqe, 2015)
.

2.6 Composition of Bitumen

A very large number of molecular species that differ greatly in polarity and
(Hung et al., 2019)
molecular weight make up bitumen . It is challenging to make a

precise geographical generalization since elemental research reveals that bitumen

composition is predominantly influenced by the source of its crude oil. The major

components of bitumen, according to numerous reports, are carbon, which ranges from

80 to 88 wt%, and hydrogen, which ranges from 8 to 11 wt%. The following

heteroatoms and transition metal atoms are also typically present: sulfur (0 to 9 wt%),

nitrogen (0 to 2 wt%), oxygen (0 to 2 wt%), vanadium up to 2000 ppm, and nickel up to

200 ppm. Bitumen contains complex mixture of several chemical compounds which

make chemical characterization difficult. Due to this reason, simpler methodology is

(Porto et al., 2019)
used to obtain bitumen which allow two constituents to be identify .

2.6.1 Asphaltene
Asphaltenes are amorphous brown/black solids with particle sizes ranging from

5 to 30 m at room temperature. They are insoluble in n-heptane but soluble in toluene.

Their percentage in bitumen ranges from 5 to 25 percent. In the form of complexes like

metallo-porphyrins with long aliphatic chains (up to 30 carbon atoms) and pyrrolic and

15
pyridinic rings, asphaltene contains oxygen, nitrogen, sulfur, and heavy metals (V, Ni,

etc.). Asphaltene molecules are composed of fused aromatic rings, most likely between

4 and 10 units, along with some aliphatic chains as ring substituents. This is proven by

UV-fluorescence spectroscopy, Fourier transform infrared spectroscopy, X-ray raman

(Porto et al., 2019)
spectroscopy, and NMR spectroscopy .

2.6.2 Malthenes (also called petrolenes)

Maltenes are divided into three groups: saturate, aromatic, and resin. These

three groups—along with asphaltene—are collectively referred to as the bituminous

SARA fraction.

2.6.2.1 Saturates
Bitumen's saturated components generally make about 0 to 15 weight percent of

the total fraction. Saturates are complicated mixes of polyalkyl structures from a

chemical perspective, and FTIR measurements reveal that straight chain paraffins

predominate in these mixtures. Long-chain paraffins are more abundant in the saturated

fractions from blown bitumen than they are in straight-run bitumen. Pure aliphatics

make up the majority of the saturate portion (linear and cyclic). Because the saturate

fraction is the lightest part of the maltenes and the latter are a liquid portion of bitumen

that are complemented by solid asphaltenes, a drop in the complex shear modulus and

an increase in the phase angle of bitumen are predicted as the concentration of saturates
(Porto et al., 2019)
rises .

2.6.2.2 Resins
Dark brown solid (or semi-solid) substances known as resins with particles that

range in size from 1 to 5 nm, are soluble in n-heptane, and are physically and

chemically identical to asphaltenes with the exception of having a lower molar mass.

Resins can occasionally be more polar than asphaltenes but have less condensed

16
aromatic rings. They are present in amounts between 30 and 45 wt%. Although their

polar nature improves the bitumen's adhesive capabilities, their main function is as

dispersants for the mutually insoluble asphaltene macromolecular structures and oils.

Resins accumulate oxygen molecules during bitumen oxidation, which increases how

close their structural makeup is to that of asphaltenes. The resins' asphaltene ratios have
(Porto et al., 2019)
a significant role in determining the bitumen properties .

2.6.2.3 Aromatics
Low molecular weight aromatic chemicals are found in aromatic oils, which are

dark brown, viscous liquids. Their molar mass ranges from 300 to 2000 g/mol, and they

feature an aromatic ring structure with a mildly condensed carbon skeleton. The

majority of bitumen (40–65%) is made up of aromatic oils. Compared to high molecular

weight hydrocarbons, they have a high solvent power. They are regarded as the
(Porto et al., 2019)
bitumen's plasticizing agents, together with saturated oils .

2.7 Properties of Bitumen

2.7.1 Adhesion
All of the components are joined together by bitumen's adhesive quality without

experiencing any positive or negative alterations to their characteristics. Depending on

the surface's characteristics, bitumen has the capacity to stick to a solid surface in a fluid

condition. Water on the surface will keep things from sticking

(Oliviero Rossi et al., 2015)
.

2.7.2 Resistance to water

Bitumen can act as a reliable sealant since it is insoluble in water. Bitumen

resists water. Minuscule amounts of inorganic salts in the bitumen or filler may
(Oliviero Rossi et al., 2015)
occasionally absorb water under certain circumstances .

17
2.7.3 Hardness
The penetration test, which measures the depth of penetration of a weighted

needle in bitumen after a specific period at a particular temperature, is used to determine

the hardness of bitumen. At a temperature of 77 °F, a weight of 100 g is typically

applied for 5 seconds. Hardness is determined by the penetration. Hard coating asphalt

typically yields 10 results, roofing asphalt 15 to 40 results, and water proofing bitumen

100 outcomes or more. The majority of the time, industrial applications employ grades

with penetrations more than 40 for building roads. Only industrial applications employ

grades with penetrations lower than 40. Lower grades, such 60/70, are utilized in hotter
(Oliviero Rossi et al., 2015)
climates .

2.7.4 Viscosity and flow

When bitumen is processed and applied at high temperatures as well as when it

is used at moderate temperatures, its viscosity or flow qualities are crucial. Temperature

and stress levels have a significant impact on the flow characteristics of bitumen.

Hardening is a symptom of bitumen degradation, or loss of its favorable characteristics.

As a result, the softening point temperature and coefficient of thermal expansion rise,
(Oliviero Rossi et al., 2015)
but adhesive and flow characteristics decline .

2.7.5 Softening point

This characteristic enables us to determine if a given bitumen may be utilized at

a specific location; specifically, the softening point value must be greater than the

pavement temperature in order to prevent the bitumen existing in the layer from

softening and leaking out. The steel ball's known depth into the bitumen when the test

assembly is heated at a given pace is known as the softening point. Typically, the test

involves allowing a (3/8) in diameter, 3.5 gm-weight steel ball to pass through a (5/8) in

diameter, 1/4 in-thick disk of bitumen inside a brass ring. At a rate of 9 °F per minute,

18
the entire assembly is heated. For coating grade asphalts, typical values would be 240

°F, for roofing asphalt 140 °F to 220 °F, and for bituminous water proofing material as
(Oliviero Rossi et al., 2015)
low as 115 °F .

2.7.6 Ductility
To find out how much bitumen will stretch at temperatures below its softening

point, a ductility test is performed. In a tester set to 77 °F, a briquette with a 1in 2 cross

section is put. Depending on the kind of bitumen, ductility values might range from 0 to

over 150. The film and coating would properly form if ductility were present
(Oliviero Rossi et al., 2015)
.

2.7.7 Specific gravity

A binder's specific gravity has no bearing on how it behaves. However, mix
(Oliviero Rossi et al., 2015)
design still need its worth. At 27oC, the property is decided .

2.7.8 Durability
The phrase "bitumen durability" describes a material's long-term resistance to

oxidative hardening in the field. Although all bitumen in service hardens with time due

to reaction. With oxygen present in the air, rapid hardening rates (poor durability) can

cause surface failure, early embrittlement of the binder, and chip and crack loss. If

properly cared for over the course of the pavement's life, bitumen can last up to twenty
(Oliviero Rossi et al., 2015)
years .

2.7.9 Versatility
Because of bitumen's thermoplastic properties and adaptability, it is quite simple

to employ in various applications. As it liquefies when heated, making the operation

simpler, then hardens in a solid mass when cooled, it may be distributed easily
(Oliviero Rossi et al., 2015)
throughout the underlying pavement layers .

19
2.7.10 Strength
Although bitumen or asphalt also plays a crucial function in dispersing the

traffic loads to the layers below, coarse aggregates are the principal load-bearing
(Oliviero Rossi et al., 2015)
component of a pavement .

2.8 Bitumen Modification

Pure/virgin bitumen possess adequate performance characteristics, but

increasing the high temperature performance can sometimes lessen the low temperature

performance properties of the bitumen. The development of steps to counter this effect

has been the incentive that has driven the early stages of the development of polymer

modified bitumen (PMB) for use in roads. Modified bitumen is bitumen whose

properties have been changed by the use of a chemical agent that, when added to the

original bitumen, alters its chemical structure and physical and/or mechanical properties
(Shaqe, 2015)
.

There is a complex relation between bitumen chemical structure, bituminous

colloid structure, and its physical and rheological properties. Any material which

changes the chemical structure of bitumen consequently changes the properties of

bitumen, and as a result, it can be a modifier. Ideally, modified bitumen has more

adhesion than pure bitumen and lower thermal sensitivity in the range of service

temperatures and sufficient viscosity at execution temperature. In addition, its

sensitivity to the time of loading is low, and its strength to plastic deformation, fatigue,

and cryogenic cracks is high. Eventually, its properties after aging are good for
. (Honarmand et al., 2019)
execution and service .

One of the prime roles of many bitumen modifiers is to increase the resistance of

the asphalt to deformation at high road temperatures without adversely affecting the

20
properties of the bitumen or asphalt at other temperatures. This is achieved by one of

the two following methods, both of which result in a reduction in the permanent strain.

The first approach is to stiffen the bitumen so that the total visco-elastic response of the

asphalt is reduced. The second approach is to increase the elastic component of the

bitumen, thereby reducing the viscous component. Increasing the stiffness of the

bitumen is also likely to increase the dynamic stiffness of the asphalt. This will improve

the load spreading capability of the material, increase the structural strength and

lengthen the expected service life of the pavement. Alternatively, it may be possible to

achieve the same structural strength but with a thinner layer. Increasing the elastic

component of the bitumen will improve the flexibility of the asphalt. This is important
(Shaqe, 2015)
where high tensile strains are induced . The different types of modifiers

and their examples are shown in Table 2.4

21
Table 2. 4 The common types of modifiers are listed below
Type Examples Abbreviation

Thermoplastic elastomers - Styrene–butadiene elastomer SBE

- Styrene–butadiene–styrene SBS
elastomer (linear or radial)
- Styrene–butadiene rubber SBR
- Styrene–isoprene–styrene SIS
- Styrene–ethylene–butadiene– SEBS
styrene elastomer

Latex - Natural rubber NR

Thermoplastic polymers - Ethylene–vinyl acetate EVA
- Ethylene–methyl acrylate EMA
- Ethylene–butyl acrylate EBA
- Atactic polypropylene APP
- Polyethylene PE
- Polypropylene PP
- Polyvinyl chloride PVC
- Polystyrene PS
Thermosetting polymers - Epoxy resin
- Polyurethane resin PU
- Acrylic resin
- Phenolic resin
Chemical modifiers - Sulfur S
- Phosphoric acid, polyphosphoric PA, PPA
acid
- Sulfonic acid, sulfuric acid
- Carboxylic anhydrides or acid
esters
- Dibenzoyl peroxide
- Silanes
- Organic or inorganic sulfides
- Urea
Recycled materials - Crumb rubber, plastics
Fibers - Lignin
- Cellulose
- Alumino-magnesium silicate
- Glass fibres
- Asbestos
- Polyester
- Polypropylene PP
Natural asphalts - Trinidad Lake Asphalt TLA
- Gilsonite
- Rock asphalt
Reactive polymers - Random terpolymer of ethylene,
acrylic ester and glycidyl
methacrylate

22
 - Maleic anhydride-grafted
styrene–butadiene–styrene
copolymer

Source: (Shaqe, 2015)

2.9 Polymer Modification of Bitumen

Polymers are macromolecules synthesized through chemical reaction between

smaller molecules (monomers) to form long chains. The physical properties of the

resulting polymer are determined by the chemical structure of the monomers and by

their sequence inside the polymer. A combination of two different monomers that can

be in a random or block arrangement gives a so-called copolymer. Polymers include a

broad range of modifiers with elastomers and plastomers being the most commonly-
(Porto et al., 2019)
used types. .

By adding polymers, the chain of small molecules is repeated, and as a result,

the pavement performance improves. Polymer-modified bitumen increases strength

against rutting and fatigue and cryogenic cracks and reduces damask and thermal

sensitivity. So, polymer-modified bitumen are used successfully in places with high

stress such as intersections, airports, truck weighing areas, and race routes. The positive

properties of polymeric bitumen include increase of elastic recovery, viscosity,

(Honarmand et al., 2019)
softening point, adhesion, and flexibility. .

Polyethylene, polypropylene, polyvinylchloride, polystyrene and ethylene–vinyl

acetate (EVA) copolymer are the main non-rubber thermoplastic polymers that have

been examined in recent decades. As thermoplastic polymers, they are characterized by

softening on heating and hardening on cooling. These polymers tend to influence the

penetration more than the softening point properties when added to bitumen, which is

the opposite tendency of thermoplastic elastomers. Polyolefins have been used for the

23
modification of bitumen due to their relatively low cost and the benefits that they

induce.

The light components of bitumen are usually absorbed by the polyolefins. A bi-

phasic morphological structure is formed (i.e. the polyolefin is dispersed in the bitumen

matrix). As the concentration of the polymer increases, phase inversion phenomena

occur, leading to a polymer matrix that can be detected in higher concentration

polyolefin modified bitumen formulations. In addition to this, the regular and long

chains of polyolefin materials have a tendency to pack closely and crystallize, which

leads to a lack of interaction between the bitumen and the polyolefin and causes

instability of the modified bitumen. The compatibility of polyolefins with bitumen is

usually found to be very poor because of the non-polar nature of the polyolefin

materials. (Fawcett and McNally, 2000; Yousefi, 2003)

Polymer-modified bitumens (PmBs) are produced by the mechanical mixing or

chemical reactions of a bitumen and one or more polymer in a percentage usually

ranging from 3% to 10%, relatively to the weight of bitumen. In the first case, the

mixtures are said to be simple, because no chemical reactions occur between the two

partners in the system. In this case, the polymer is considered as a filler which gives

specific properties to the mixture. In the second case, the mixtures are said to be

complex, because chemical reactions or some other interaction occurs between the two
(Porto et al., 2019)
partners in the system. .

EVA copolymers, as thermoplastic materials, has a random structure produced by

the copolymerization of ethylene and vinyl acetate. EVA copolymers with a low vinyl

acetate content possess properties similar to low density polyethylene. As the level of

vinyl acetate increases, the properties of the copolymer alter, which may induce changes

24
in the properties of the bitumen. The properties of EVA copolymers are classified by

molecular weight and vinyl acetate content as follows.

Molecular weight: Standard practice for EVAs is to measure the melt flow index

(MFI), a viscosity test that is inversely related to the polymer molecular weight: the

higher the MFI, the lower the molecular weight and viscosity. This is analogous to the

penetration test for bitumen: the higher the penetration, the lower the average molecular

weight and viscosity of the bitumen.

Vinyl acetate content: Regular polyethylene segments of the EVA chain pack

closely together and form so-called ‘crystalline’ regions, and can be represented

graphically, showing the main effects of vinyl acetate species on the properties of a

bitumen. At the same time, the bulky vinyl acetate groups disrupt this closely packed

arrangement to give ‘non-crystalline’ or ‘amorphous rubbery’ regions. The crystalline

regions are relatively stiff, and have a considerable reinforcing effect whereas the

amorphous regions are rubbery. Obviously, the more vinyl acetate groups present (or

the higher the vinyl acetate content), the higher the proportion of rubbery regions will
(Luo et al., 2011)
be, and, conversely, the lower the proportion of crystalline regions .

A wide range of EVA copolymers is available, specified by both the MFI and the

vinyl acetate content. EVA copolymers are easily dispersed and have good

compatibility with bitumen. They are thermally stable at the temperatures at which

asphalt is normally mixed. However, during static storage, some separation between the

polymer and bitumen may occur, and it is therefore recommended that the blended
(Shaqe, 2015)
product should be thoroughly mixed before use .

25
 CHAPTER THREE

RESEARCH METHODOLOGY
3.1 Materials

The following materials were used for this research work; Pure Natural

Bitumen, Tar sand (bitumen containing some materials such as sand, clay, etc.),

Polyethylene, Polypropylene, Butyl Acrylate, Poly (Styrene-co-Butadiene), Poly

(ethylene-co-vinyl-acetate), Kerosene, Petrol (PMS).

3.2 Equipment and Apparatus

Equipment and apparatus used for this research work are beakers (25ml, 50ml,

100ml, 250ml and 500ml), measuring cylinder (25ml and100ml), conical flask, sample

bottles, oven, magnetic stirrer, high shear mixer (RWD50), microwave, multi-

thermometer (MEXTECH), precision weighing balance, tin container, plastic

containers, iron bucket, iron sponge, gloves, penetrometer (intelligent asphalt

penetration tester) moving die rheometer and compressor. Table 3.1 shows some the

various equipment used and their function.

3.3 Reagents

The only reagent used for this research work is petroleum ether/spirit and the
sample is shown in Plate 3.1

3.4 Instruments

Fourier-transform infrared (FTIR) spectrometer, Thermogravimetric Analyzer

(TGA), Scanning Electron Microscope (SEM), Energy-Dispersive X-ray (EDX), DSC.

26
 Table 3. 1 Equipment and their function
Equipment Function

Measuring cylinder Used to measure the quantity of solvent

needed

Weighing balance To measure the weight of material used

Tin container Used to keep the purified tar sand and

bitumen

Beakers Bitumen is placed in them for heating

Plastic container Some are used for keeping bitumen and

to transfer bitumen for characterization
while others are used in mixing tar sand
and solvent

Stirrer Used for mixing tar sand and solvent

Oven For heating the purified tar sand

containing solvent

XRD Used for quantitative analysis. To

determine the thickness, roughness and
density of bitumen

FTIR Used in polymer science to determine

molecular structure of substance

TGA Used to characterize materials by

measuring their change in mass as a
function of temperature

SEM Produces image that provide

information on topography,
morphology and composition

EDX Used to analyze the elemental

composition of solid surface

27
Plate 3.1 Petroleum Ether bottle sample
Source: Author’s Camera, 2023

28
3.5 Methods

3.5.1 Sample Procurement and Location

Bitumen and tar sand was obtained from (4) different location which are Lagos

axis, Ogun axis, Ondo axis and Edo axis. Pure natural bitumen was collected from one

of the wells sunk by the Nigeria Bitumen Corporation (NBC) located opposite Saint

Stephen’s Primary School, Agbabu, Ondo State (Longitude 3°45ˈE and 5°45ˈE and

latitudes 6°00ˈN and 7°00ˈN). Two of the three tar sand samples that was used was

collected from two different locations in Ijebu, Ogun State; Abigi (Latitude 6.68 °N and

Longitude 4.31 °E), Sunbare (Latitude 6.71°N and Longitude 4.36 °E), and the last

sample was collected from Loda (Latitudes 6°65ˈN and Longitudes 4°88ˈE) in Ondo

State. The tar sand sample was collected from the surface of the ground from the vast
(Ndicho, et al., 2011; Ogiriki, et al., 2018; Olabemiwo et al., 2016).
tar sands outcrops.

Plate 3.2 – Plate 3.4 show the pictorial representation of the three tar sands deposit

in Nigeria, which is from Loda, Abigi and Sunbare.

29
Plate 3. 2 Loda tar sand sample deposit
Source: Author’s Camera, 2023

Plate 3. 3 Abigi tar sand sample deposit

Source: Author’s Camera, 2023

30
Plate 3. 4 Sunbare tar sand sample
Source: Author’s Camera, 2023

31
3.5.2 Extraction and Purification of Bitumen from Tar Sand
The obtained tar sand samples was in a solid compact form. It was difficult to

work with the tar sand samples in this form therefore, the samples were crushed into

smaller sizes. The solvent extraction technique was used to separate the bitumen from

other composition contained in the tar sand, using petroleum ether as the solvent. The

tar sand was soaked in the solvent in a container and stirred to obtain homogenous

mixing of the particles and then make to saturate for 24 hours.

The bitumen was at the top of the solution while sand and other particles settle

below the bitumen and the bitumen was then decanted. The extracted bitumen (which

contains bitumen and petroleum ether) was purified by heating it in an oven at a

temperature of 100 °C for about 1 hour to remove the petroleum ether and also to
(Spirov et al., 2013).
reduce the moisture content of the bitumen Plate 3.5 show the

pictorial representation of the extraction and purification process.

32
Plate 3. 5 Purification Process of Bitumen
Source: Author’s Camera, 2023

33
3.6 Procedure for physical and mechanical test for the bitumen samples

3.6.1 Procedure for Viscosity

The sample was poured into a container (beaker, conical flask or test tube),

spindle (either Spindle 1, 2, 3 or 4 depending on the thickness of the sample) was

attached to the viscometer and then inserted into the sample, till the marked point on the

spindle, making sure the spindle was not touching the container vessel. The experiment

was run at specific time (seconds) for each sample. The RPM (speed rate), Spindle

Number, Temperature, %Torque and Viscosity reading @mPascal were noted and

recorded after each run for each sample.

3.6.2 Procedure for Softening Point

3.6.2.1 Sample preparation

Take bitumen sample in a vessel and heat to a temperature of 75- 100 above

its approximate softening point. Allow the bitumen to melt until it is converted

completely into a liquid state. Stir the bitumen if necessary, so that it is melted

completely and is free from air bubbles and water. If the need arises, filter it through 1s

sieve 30. Prepare a mixture of glyceride and dextrine in equal proportion. Mix it well.

Then coat the square of the metal or glass plate. This prevents the bitumen from sticking

to the plate.

Heat the rings to approximately same temperature as that of the molten

bitumen and place them on the glass or metal place coated with the mixture of glycine

and dextrine. Pour the molten bitumen in the rings carefully till the rings are slightly

filled above the top level. Allow the rings to cool at room temperature in air for

30minutes. Cut the excess bitumen in the surface with the help of hot, straight edged

putty knife or spatula and level the top surface.

34
3.6.2.2 Testing the specimen
Fill the water bath with freshly boiled distill water to such a height that the water

level remains 50mm above the upper surface of the rings. Maintain this water bath at 5-

degree temperature. Fix the rings filled with bitumen to the ball guide. Assemble the

rings in the support frame. Place the rings fixed to the support frame in the support

frame in the water bath at 5 degree for 15minutes. Cool the steal ball to a temperature of

5 degree. Place a steel ball on top of the ring guide of the rings attached to the support

with the help of forceps. Place this assembly in a glass beaker filled with distilled water

to such a height that the water level is at least 50mm above the top surface of the ball.

Put the beaker on the hotplate and adjust the stirrer.

Insert the thermometer too. Allow the beaker to be heated at a uniform rate of

5+-0.5degree per minute. The rate can be adjusted with the help of energy regulator. Stir

the water continuously to ensure that the water is heated uniformly. Continue the

heating till the bitumen filled in the rings soften and the ball placed on it start to move

down owing to its own height. Note the temperature when each of the balls touches the

bottom plate while sinking from the thermometer.

3.6.3 Procedure for Ductility Test

3.6.3.1 Sample preparation

Take the bitumen sample in a beaker and heat it to a temperature of 75-100

degree above its approximate boiling point. Allow the bitumen to melt until it is

converted completely into a liquid state. Prepare a mixture of Glycine and Dextrin in

equal proportions. Mix it well. Then coat the surface of the brass plate and the interior

of the sides of the briquette mould. This prevents the bitumen from stickling to the

mould. Fix the sides clip over the base plate and tighten the screw of the clip with the

help of a screwdriver.

35
 Pour the melted bitumen into the briquette mould until they are fall. Allow the

mould to cool at room temperature in the air for about 30-40minutes. Place the whole

assembly with brass plate and mould in a water bath which is maintained at 27 oC for

about 30 minutes. Cut the excess bitumen on the surface with the help of a hot, straight

– edged knife or spatula and level the top surface. The dimension of the briquette thus

formed is exactly 1sq cm.

3.6.3.2 Testing the specimen

Place the brass plate along with mould containing the specimen again in the

water bath at 27oC for 85-95 minutes. Remove the briquette from the base plate,

unscrew the clips and remove the sides of the briquette. Attach the assembly of bitumen

sample with a base plate with the help of the rings of the pins to the pins or hooks in the

ductility machine. One clip of the mould is attached to the fixed part of the ductility

machine. Tighten the screw of the clips of the mould with the help of a screwdriver.

Check the pointer of the ductility machine is at Zero (or note the down the initial

reading of the ductility machine). Switch on the ductility machine and adjust the gear so

that the movable part moves at the speed of 50mm/minute. (the pull rate of machine as

to be maintained 50mm/min). Thus, the two clips are pulled apart horizontally at

uniform speed until the briquette specimen ruptures. Measure the distance between the

clips at the time of rupture of the specimen.

3.6.4 Procedure for Penetration Test

3.6.4.1 Sample Preparation

Take the bitumen sample in a beaker and heat it to a temperature of above

approximate softening point. For tars and pitches, it is heated up to 60 °C while bitumen

is heated up to 90 °C. Allowed the bitumen to melt until it achieves a pouring

consistency. Keep stirring the sample so that the sample is homogenous and free from

36
air bubble and water. Pour the melted bitumen into the container at 35 mm depth until it

is filled up to a depth of 10 mm more than expected penetration. Place the container on

a transger dish and allow it to cool in the atmosphere at a temperature in between 15 °C

– 30 °C for 1.5 - 2.0 hours when a 45 mm deep container is used.

Place the whole assembly with the container and transfer the dish to a water

bath, which is maintained at 25 +/- 0.1 °C for about 1.5 - 2.0 hours when a 35 mm deep

container is used. The time period is reduced to 1.0 - 1.5 hours when 45 mm deep

container is used. When cut back the bitumen or digboi type bitumen is to be tested, the

residue left after the distillation process is used for this test

3.6.4.2 Testing the Specimen

Remove the transfer dish from the water bath and fill the water from the water

bath in the dish to such a depth that the container is covered completely. Place the

sample container in this transfer dish and place this assembly under the penetration

needle on the penetrometer. Clean the needle with cotton dabbed in benzene and allow

it to dry. Load the needle to the specified weight. Adjust the needle so that its tip just

touches the surface of the bitumen sample. Finely adjust the needle by raising the

platform slightly with the help of adjusting the screw.

Check the contact of the needle to the surface of bitumen by observing the image

of the needle reflected by the surface of the material. Clamp the needle in this position.

Load the needle holder with a weight such that the total moving weight is equal to 100

+/- 0.25gramma.

Moving weight = Weight of Needle + Weight of Carrier + Super Imposed Weight.

Note than the initial reading of the dial of the penetrometer or bring down the

pointer to zero. In a standard penetrometer, release the needle for exactly 5 seconds by

pressing the knob. Measure the time with the help of a stop watch. In an automatic

37
penetrometer, release the needle for exactly 5 seconds by pressing the start button.

Rotate the knob on the dial and note than the final reading from the dial as the

penetration value is one-tenth of a millimeter. Clean the needle with benzene after every

test and allow it to dry. Take at least 3 penetration values on the surface of the sample

(for a sample with penetration value > 25mm, leave the needle in the sample and use

another needle to take another reading so that the sample is not disturbed).

Distance between the two-test point not </= 10mm

Distance between the test point and the side of the dish not </= 10mm

Take out the average of the three values and note it as the penetration value of

the sample. If the penetration ratio is to be determined, carry out the entire test

procedure at 4oC, tolerance of 0.1oC can be allowed. In this test, take out the total

weight on the penetration needle = 200+/-0.25gramms. Increase the time penetration to

60 seconds.

3.6.5 Determination of Flash Point

The flash point of the bitumen was determined according to the ASTM D 93

open cup method. The cup was filled with a sample of the bitumen up to the mark

(75ml) and the cup was heated with a bunsen burner maintaining a small open flame

from an external supply of natural gas. Periodically, the flame was passed over the

surface of the bitumen. When the flash temperature\ was reached the surface of the

bitumen caught fire. The temperature (at the moment) was noted and recorded as the

flash point temperature.

3.6.6 Determination of Cloud Point

The cloud point of the bitumen was determined according to the ASTM D 5773

method. The cloud point is a measure of the temperature at which components in the oil

38
begin to solidify out of the solution. A test tube with a thermometer inserted in it, was

filled with a sample of the bitumen. The oil was cooled at 2 °C/min rate and

continuously monitored until a white cloud appeared on the bulb of thermometer. The

temperature that corresponds to the first formation of a cloud in the oil was recorded.

3.6.6 Determination of the Pour Point of the Bitumen

The pour point of the bitumen was determined according to the ASTM D 97-96a

method. A sample of the bitumen in a capillary tube was solidified; thereafter, it was

attached to a thermometer and inserted into a gradually heating beaker of water. The

temperature at which the sample started moving in the capillary tube was recorded.

3.7 Characterization of the Nigeria Natural bitumen

3.7.1 Thermogravimetric Analysis (TGA)

Thermogravimetry is one of the thermal analysis methods. The weight of the

selected test sample was measured as a function of temperature or time at which the

sample is exposed to heat. The test sample tends to lose weight due to debonding of the

structural chains as a result to degraded components. Contrarily, its weight could

increase because of a reaction with gas which occurs during heating and better known as

oxidative ageing. The data for thermogravimetric (TGA) analysis is expressed as a

percentage change in weight as a function of the temperature which form the TG curve.

In this study, thermal analyses were performed to determine the unmodified and

modified thermal behavior of the bitumen. TGA was performed to observe any changes

in the decomposition curves which are caused by the addition of the polymer (butyl
(Khairuddin et al., 2019).
acrylate) additives to the bitumen

39
3.7.2 Fourier Transform Infrared (FTIR) Spectroscopy

Infrared spectroscopy was used to identify and quantify the chemical functional

groups of the modified bitumen for wavenumbers ranging from 400 cm−1 to 4000

cm−1. All spectra were analyzed to determine the changes in the chemical composition

through oxidative ageing in which the carbonyl and sulfoxide groups were analyzed.
(Khairuddin et al., 2019)
. The unmodified and modified samples formed at room

temperature were directly placed under the infrared spectrometer probe. The number of

scans was 64 times and the resolution was 4 cm.

3.7.3 Differential scanning calorimetry (DSC)

Differential scanning calorimetry (DSC) was used to measure the endothermic

heat release thermograms of the unmodified and modified bitumen. A DSC 823e

(Switzerland Mettler-Toledo) was used for these tests using an argon atmosphere to

blanket the samples, the heating rate was 10 °C/min, the temperature range was from -
(Fang et al., 2014).
50 to 230 °C

3.7.4 SEM (Scanning Electron Microscopy).

With a resolution of 4.0 nm, the high performance, variable pressure scanning

electron microscope (PHENOM pro-X) will be used to examine the microscopic

structure of both natural and modified bitumen. Its computer-controlled five-axis stage

is located inside a specimen chamber that has a 0.5kg maximum weight capacity. All of

the instrument's usual automated features—focus, stigmator, gun saturation, gun

(Mazumder et al., 2018)
alignment, contrast, and brightness—are automated .

3.7.5 Conventional physical test methods

In addition to the chemical analysis, test procedures capturing the bitumen's

physical characteristics will be conducted. These include common test procedures such

determining the needle penetration and the softening point (ring-and-ball). The

40
penetration index will be determine using the softening point and needle penetration
(Nizamuddin et al., 2020)
.

3.8 Modification of the Bitumen

Polymer modification of bitumen is the incorporation of polymers in bitumen by

mechanical mixing or chemical reaction. In these research work, various polymers such

as plastomers (e.g. polyethylene (PE), polypropylene (PP), and ethylene– vinyl acetate

(EVA)) and thermoplastic elastomers (e.g. styrene–butadiene–styrene (SBS), and

styrene–isoprene–styrene (SIS)) will be used for modification. Although none of these

were initially designed for bitumen modification. These polymers were reported to lead

to some improved properties of bitumen, such as higher stiffness at high temperatures,

higher cracking resistance at low temperatures, better moisture resistance or longer

(Zhu et al., 2014)
fatigue life .

Polyethylene (PE) is a Polyolefinic Plastomer (also known as thermoplastic),

which can be found in three forms; low-density polyethylene (LDPE), high-density

polyethylene (HDPE), and linear low-density polyethylene (LLDPE). The use of

Polyolefin polymers as modifiers generally increases the bitumen stiffness and a good

rutting resistance. Polyethylene is gotten from low-density domestic waste PE carry

bag. Polymer-bitumen blend will be prepared using a conventional mechanical mixer

where a defined amount of bitumen was heated up to 135ºC in a blending vessel in

(Shallsuku, 2018)
order to obtain a bitumen fluid enough to be easily stirred .

Mass of the bitumen used will be 5% weight of the polymer used. LDPE was

added to the purified bitumen at 170°C using a high-speed stirrer rotating at 3500 rpm,

and blending was done for a period of 20 minutes to obtain a homogenous binder. This

temperature ensured that both, polymers and bitumen were always above their softening

41
point temperature. Temperature, mixing speed and blending time were chosen

according to conditions reported by previous researchers. However, mixing speed and

blending time have not been standardized and different researchers have used various
(Zhu et al., 2014).
mixing conditions to obtain similar result.

To begin with, 500 g of the base bitumen was placed in the iron container and

heated to 190 C. This material was then sheared using a FLUKO FM300 high shear

emulsifier. The shear mixer’s speed was maintained at 1200 rpm, as 20 g of the WPE

particles was added into the base bitumen over 5 min, with continuous shearing of the

mixture. The temperature was maintained at 190 °C during this process and the mixture

was sheared for 30 min, the preparation of sample 1 was completed

(Olabemiwo et al., 2015)
. This is shown in plate 3.6.

42
Plate 3. 6 Modification Process of Bitumen
Source: Author’s Camera, 2023

43
 Using this general procedure, we proceeded to prepare three additional

samples. Samples 2–4 were obtained at the shearing temperature of 190 °C, using

shearing times of 1, 1.5 and 2 h, respectively. Samples 5–8 were obtained at the

shearing temperature of 170 °C and a shear time of 0.5, 1, 1.5 and 2 h and 9–12 samples

were obtained at the shearing temperature of 150 °C with a shear time of 0.5, 1, 1.5 and

2 h. In each preparation process, modified bitumen samples were all swelled for 10 min
(Fang et al., 2014)
after each half hour of shearing .

3.9 Experimental design for bitumen modification

The general workflow adopted in the course of this study is summarized in
Figure 3.1

44
 Sample collection

Sample purification

Characterization (FTIR, SEM,

TGA)

Physical properties
determination using standard
Methods

Design of Experiment for

Polymeric Modification using
Polystyrene- co-butadiene (PCB)

Optimization study

Figure 3. 1 The workflow for the research

45
 CHAPTER FOUR

RESULTS AND DISCUSSION

4.1 Energy-Dispersive X-ray (EDX)

EDX proves to be a valuable resource in examining the essential elemental

attributes of bitumen. Table 4.1 illustrates that the primary mineral components found in

Agbabu natural bitumen are carbon (93.95%), oxygen (2.31%), sulfur (0.83%), and

iridium (2.92%). The results were similar to the one obtained by

El-Shorbagy et al., 2019
. The percentage weight of the sigma bond is also shown in Table 4.1together with

the atomic weight percent. Fig. 4.1 shows the graphical representation of the elemental

composition of the Agbabu natural bitumen as depicted in the Energy Dispersive X-ray.

The results show that Ir is the only metal component present in Agbabu natural bitumen.

46
Table 4. 1 Elemental composition of Agbabu natural bitumen

Element Wt% Wt% Sigma Atomic %

C 93.95 0.22 97.69

O 2.31 0.19 1.8

S 0.83 0.03 0.32

Ir 2.92 0.13 0.19

47
Figure 4. 1 Graphical Representation of Elemental composition of Agbabu
natural bitumen

48
 Table 4.2 show the main mineral phases for Loda bitumen which are C

(88.42%), O (10.15 bitumen %), S (1.17%), and Ir (bitumen 0.26%). The percentage

weight of the sigma bond is also shown in the Table together with the atomic weight

percent. Fig. 4.2 shows the graphical representation of the elemental composition of the

Loda natural bitumen as depicted in the Energy Dispersive X-ray. The results show that

Ca is the only metal component present in Loda sample.

49
Table 4. 2 Elemental composition of Loda bitumen

Element Wt% Wt% Sigma Atomic %

C 88.42 0.66 91.57

O 10.15 0.66 7.89

S 1.17 0.09 0.45

Ca 0.26 0.07 0.08

50
Figure 4. 2 Graphical Representation of Elemental composition of Loda
bitumen

51
 The main mineral phases found in Abigi bitumen are shown in Table 4.3, and

they are carbon (83.98%), oxygen (8.53%), aluminum (2.61%), silicon (2.88%), sulfur

(1.2%), and iron (0.81 percent ). The table also includes data on atomic weight % and

sigma bond weight percentage. Additionally, using Energy Dispersive X-ray analysis,

Fig. 4.3 illustrates the constituent makeup of Abigi bitumen. The results show that the

Abigi sample, which contains aluminum (Al), silicon (Si), and iron (Fe) in its

composition, has a greater metal composition than Agbabu and Loda bitumen.

52
Table 4. 3 Elemental composition of Abigi bitumen

Element Wt% Wt% Sigma Atomic %

C 83.98 0.65 89.92

O 8.53 0.64 6.86

Al 2.61 0.12 1.25

Si 2.88 0.12 1.32

S 1.2 0.09 0.48

Fe 0.81 0.17 0.19

53
Figure 4. 3 Graphical Representation of Elemental composition of Abigi
bitumen

54
 The main mineral phases found in Sunbare bitumen are shown in Table 4.4.

They are carbon (82.98%), oxygen (7.92%), aluminum (3.41%), silicon (3.9%), sulfur

(1.22%), and titanium (0.57 percent). The table also includes information on atomic

weight % and sigma bond weight percentage. Additionally, using Energy Dispersive X-

ray analysis, Fig. 4.4 presents the constituent makeup of Sunbare bitumen in a visual

manner. The results show that the Sunbare sample's composition closely reflects that of

Abigi bitumen. Due to the fact that both samples are situated along the same axis, the

Ogun axis, this similarity can be explained.

55
Table 4. 4 Elemental composition of Sunbare bitumen

Element Wt% Wt% Sigma Atomic %

C 82.98 0.73 89.51

O 7.92 0.72 6.41

Al 3.41 0.16 1.64

Si 3.9 0.17 1.8

S 1.22 0.12 0.49

Ti 0.57 0.15 0.15

56
Figure 4. 4 Graphical Representation of Elemental composition of Abigi
bitumen

57
 Based on the data, it is clear that sulfur, which makes up 1.22 weight percent of

the heteroatoms in the samples from Abigi and Sunbare, is the most common

heteroatom. However, Loda has a little lower carbon concentration of 95.07 weight

percent than Agbabu, which predominantly consists of hydrocarbons and has a high

carbon content of 97.67 weight percent.

58
Table 4. 5 Elemental composition of investigated four bitumen samples.

Wt%

Element Abigi Loda Agbabu Subare

C 83.98 95.07 97.69 82.98

O 8.53 4.07 1.8 7.92

Al 2.61 - - 3.41

Si 2.88 - - 3.9

S 1.2 0.61 0.32 1.22

Fe 0.81 - - -

Ir 0.25 0.19 -

Ti - - - 0.57

59
 (a) (b)

(c) (d)

4.2 SEM (Scanning Electron Microscopy).

Scanning electron microscopy (SEM) pictures of the four materials taken in their

natural form are shown in Plate 3.7. SEM was used to analyze the microstructure of the

bitumen samples and determine how well the polymer (PCB) dispersed after being

added to the bitumen. It is clear from the graphic that all of the bitumen samples have

viscoelastic characteristics, with unique surface features that differ between the samples.

Plate 3. 7 SEM Images of natural bitumen samples obtained from (a)

Abigi, (b) Loda, (c) Agbabu and (d) Sunbare.

60
4.3 Thermogravimetric Analysis (TGA)

When materials decompose or react with gaseous environments while being

heated, thermogravimetric analysis (TGA), a useful technique for doing thermal

analysis, provides important insights. TGA displays a curve that shows the amount of

weight lost by the samples at each stage of weight change, representing weight loss as a

function of temperature. The inherent characteristics of the material and specific

temperature ranges completely determine the amount of weight loss in TGA

(Nizamuddin et al., 2020).

The thermogravimetric analysis (TGA) curves for four unprocessed bitumen

samples are shown in Figure 4.5. Table 4.6 analyzes the decomposition of each sample

and shows the proportion of mass that is still present as the temperature rises. While

Agbabu and Loda bitumen samples have decomposition points at 113 °C and 110 °C,

respectively, the Abigi and Sunbare samples demonstrate a separate decomposition

point at 122 °C. These materials' unaltered, unprocessed status is what is responsible for

the rapid breakdown seen in them. Notably, the weight profiles of the Abigi and

Sunbare samples are similar, possibly as a result of their shared axis location or shared

properties.

Results from Fig. 4.5 suggest that the Abigi and Sunbare bitumen has lost more

weight during the test than Agbabu and Loda bitumen. This suggests that Loda bitumen

had lesser evaporation and higher thermal stability against heat than the remaining

sample. The TGA curve illustrates that the major weight loss for the four bitumen

samples takes place in the temperature range of 200 °C and 480 °C and slow

decomposition started between 480 °C and 710 °C near the horizontal plateau, which

indicate no further loss of mass. The mass loss at 200-480 °C is attributed to the

61
volatilization of light components of bitumen such as aromatics and saturates as well as

to the degradation of large molecules of asphalt in this temperature range

(Zhang et al., 2012).

The test circumstances have an impact on a number of variables, including the

initial and final temperatures of each thermal event seen in the TGA curves. These

variables include the rate of heating, the testing environment, the properties of the

sample, and the sample's form. The temperature for these events rises as the heating rate

is increased, delaying the arrival of thermal equilibrium. The degree of weight change in

a material during the heating process is determined by its natural qualities and occurs

within a certain temperature range.

62
 120

LODA
100
Abigi
Agbabu
80 Sunbare
weight (%)

60

40

20

0
0 100 200 300 400 500 600 700 800
Temperature (°C)

Figure 4. 5 Thermogravimetric Analysis of the Nigeria Natural Bitumen

63
Table 4. 6 Decomposition Temperature
Samples Sharp decomposition Initial Final decomposition

Temperature (°C) decomposition Temperature (°C)

Temperature (°C)

Abigi 122 177 502

Sunbare 122 177 502

Agbabu 113 170 487

Loda 111 164 489

64
4.4 Fourier Transfer Infrared (FTIR) spectroscopy

A cutting-edge tool frequently used for compound analysis, specifically to

ascertain their structure, is the spectrophotometer. This device can identify substances

based on their behavior in the infrared part of the spectrum. The Fourier Transform

Infrared (FTIR) spectrum is typically acquired from thin film samples, which are

typically thinner than 50 m. Similar to a unique fingerprint, each functional group inside

a molecule exhibits vibrational behavior at a particular wavelength. As a result, a table

listing various functional groups and their corresponding wavelengths can be used to

determine which functional groups are present in additives, pure bitumen, and bitumen

with additives. Because of their interactions with one another, each functional group

vibrates at a particular wave number in a compound.

Figs. 4.6 – 4.19 shows the transmittance values for different wavelengths for the

Abigi, Sunbare, Agbabu and Loda bitumen. The Fourier Transform Infrared (FTIR)

spectrum of neat ANB was recorded in the range of 4000-400 cm -1 as shown in Figure

4.7. Unmodified ANB has absorption peaks at 2922 cm -1, 2855 cm-1 ,1615 cm-1, 1457

cm-1, 1378 cm-1, and peaks in the region 875 cm -1, 817 cm-1, and 747 cm-1 appear as

shoulder. Assignment of functional groups in agbabu bitumen is based on some

(Olabemiwo et al., 2016)
previous studies and shown in Table 4.7 .

65
 Agbabu
120

100

80
Transmittance (%)

60 Agbabu %T

40

20

0
200 700 1200 1700 2200 2700 3200 3700 4200
wavenumber (cm-1)

Figure 4. 6 Fourier Transform Infrared Spectrocopy of Agbabu Natural

Bitumen

66
Table 4. 7 Infrared Absorption Peaks of Purified ANB
Peak (cm-1) Bond/functional group

2922 H-C-H asymmetric stretch of alkanes

2855 H-C-H symmetric stretch of alkanes

1615 C=C Stretching of alkenes

1457 C-H bending of alkanes

1378 N-O stretching of nitro groups

875 C-C stretching of alkanes

817 C-C stretching of alkanes

747 C-C stretching of alkanes

67
 The Fourier Transform Infrared (FTIR) spectrum of Sunbare were recorded in

the range of 4000-400 cm-1 as shown in Figure 4.7. Unmodified Sunbare bitumen

sample has absorption peaks at 3695 cm-1, 2923 cm-1, 2857 cm-1, 1457 cm-1, 1378 cm-1,

1097 cm-1, 1032 cm-1, 914 cm-1, 753 cm-1, 697 cm-1, 537 cm-1, 470 cm-1, and 429 cm-1.

Assignment of functional groups in Sunbare bitumen is based on some previous studies

(Olabemiwo et al., 2016)
and shown in Table 4.8 .

68
 120 Sunbare
100

80
Transmittance (%)

60 Sunbare %T

40

20

0
200 1200 2200 3200 4200
Wavenumber (cm-1)

Figure 4. 7 Fourier Transform Infrared Spectrocopy of Sunbare Natural

Bitumen

69
Table 4. 8 Infrared Absorption Peaks of Purified Sunbare Natural Bitumen
Peak (cm-1) Bond/functional group

2923 H-C-H asymmetric stretch of alkanes

2857 H-C-H symmetric stretch of alkanes

1457 C-H bending of alkanes

1378 N-O stretching of nitro groups

1097 C-C stretching of alkanes

1032 C-C stretching of alkanes

914 C-C stretching of alkanes

753 C-C stretching of alkanes

697 C-C stretching of alkanes

537 C-C stretching of alkanes

470 C-C stretching of alkanes

429 C-C stretching of alkanes

70
 The Fourier Transform Infrared (FTIR) spectrum of Loda bitumen was recorded

in the range of 4000-400 cm -1 as shown in Figure 4.8. Unmodified Loda bitumen has

absorption peaks at 2925 cm-1, 2857 cm-1 ,1707 cm-1, 1615 cm-1, 1458 cm-1, and 1378

cm-1. Assignment of functional groups in Loda bitumen is based on some previous

(Olabemiwo et al., 2016)
studies and shown in Table 4.9 .

71
 LODA
120

100

80
Transmittance (%)

60 LODA %T

40

20

0
200 700 1200 1700 2200 2700 3200 3700 4200
wavenumber (cm-1)

Figure 4. 8 Fourier Transform Infrared Spectrocopy of Loda Natural Bitumen

72
Table 4. 9 Infrared Absorption Peaks of Purified Loda Natural Bitumen
Peak (cm-1) Bond/functional group

3403

2925 H-C-H asymmetric stretch of alkanes

2857 H-C-H symmetric stretch of alkanes

1707 C=C Stretching of alkenes

1615 C=C Stretching of alkenes

1458 C-H bending of alkanes

1378 N-O stretching of nitro groups

73
 The Fourier Transform Infrared (FTIR) spectrum of Abigi was recorded in the

range of 4000-400 cm-1 as shown in Figure 4.9. Unmodified Abigi has absorption peaks

at 3696 cm-1, 2924 cm-1, 2855 cm-1 ,1708 cm-1, 1617 cm-1, 1458 cm-1, 1377 cm-1, 1094

cm-1, 1032 cm-1, 915 cm-1, 751 cm-1, 696 cm-1. Assignment of functional groups in Abigi

bitumen is based on some previous studies and shown in Table 4.10

(Olabemiwo et al., 2016)
.

74
 120 Abigi
100

80
Transmittance (%)

60
Abigi %T

40

20

0
200 700 1200 1700 2200 2700 3200 3700 4200
wavenumber (cm-1)

Figure 4. 9 Fourier Transform Infrared Spectrocopy of Abigi Natural Bitumen

75
Table 4. 10 Infrared Absorption Peaks of Purified Abigi Natural Bitumen
Peak (cm-1) Bond/functional group

3696

2924 H-C-H asymmetric stretch of alkanes

2855 H-C-H symmetric stretch of alkanes

1708 C=C Stretching of alkenes

1617 C=C Stretching of alkenes

1458 C-H bending of alkanes

1377 N-O stretching of nitro groups

1094 C-C stretching of alkanes

1032 C-C stretching of alkanes

915 C-C stretching of alkanes

751 C-C stretching of alkanes

696 C-C stretching of alkanes

539 C-C stretching of alkanes

468 C-C stretching of alkanes

460 C-C stretching of alkanes

76
 The presence of shoulders around 868 cm -1, 815 cm-1, and 744 cm-1 as observed

in Agbabu, Loda and more conspicuously in Sunbare and Abigi may be due to aromatic

bending C-H modes and these correspond to C-H bend in aromatics.

77
 120

100

80

Sunbare
60 Agbabu
Loda
40 Abigi

20

0
0 500 1000 1500 2000 2500 3000 3500 4000 4500

Figure 4. 10 Fourier Transform Infrared Spectrocopy of the four Natural

Bitumen Location

78
4.5 Differential scanning calorimetry (DSC)

A TA Instruments DSC Q2000 calorimeter was used to perform differential

scanning calorimetry (DSC) measurements while a nitrogen environment was present.

Unaltered bitumen is shown by the DSC trace in Figure 4.12, which exhibits a number

of endothermic transitions. Based on a literature data, there would be a glass transition

temperature centered on Tg ~ –26.2 °C, followed by two endotherms at T ~ 19.5 °C and

(Ahmedzade et al., 2014)
T ~ 55.7 C for the melting of saturates .

Most people are aware that bitumen is a complicated viscoelastic mixture made

up of oligomeric hydrocarbons with an average polymerization degree of around 10.

Additionally, it contains traces of molecules containing heteroatoms like sulfur,

nitrogen, and oxygen. Using chromatography, which divides bitumen into fractions such

saturates, resins, aromatics, and asphaltenes, or in terms of the concentration of

maltenes and asphaltenes, it is frequently possible to define the chemical composition of

bitumen. The de-asphaltenated component of bitumen is represented by maltenes. The

behavior of bitumen is typically explained by a colloidal model, which contains

asphaltenes distributed within an oleaginous maltene matrix and resin stabilization

(Ahmedzade et al., 2014)
.

At a temperature of about 96 °C to about 105 °C, there is a high increase in the

heat flow of the four bitumen samples but Agbabu sample has the highest heat flow

followed by the Loda sample. This implies that as the temperature is being increased,

the heat flow increases before being decrease which shows that the process is

endothermic.

79
 12
DSC Graph Loda
10 Sunbare
Abigi
8
Agbabu
Heat Flow (mW)

6 Abigi Smooth

0
0 50 100 150 200 250 300 350 400 450
-2
Temperature (°C)

Figure 4. 11 DSC analysis of four bitumen samples

80
4.6 Penetration Test of Agbabu Natural Bitumen Modified with Polypropylene

One of the empirical tests that is frequently performed on bitumen and bitumen

with polymer modifications under particular circumstances is the penetration test

(Farahani et al., 2017)
. It denotes consistency and is empirically connected to the

binder's flow and deformation properties (Bala et al., 2017). The results of penetration

test of unmodified bitumen of the four locations and polymer (polypropylene) modified

blends of Agbabu bitumen are shown in Table 4.11 and Table 4.12
(Murugan et al., 2020)
.

Comparing the value obtained from Agbabu raw bitumen to the modified

sample, it could be observed that the penetration value of the Agbabu bitumen was

significantly decreased by the addition of polypropylene, hence indicating that fluidity

is decreased and high-temperature consistency of bitumen is improved

(Farahani et al., 2017)
. The penetration value of neat bitumen was 51.27 (0.01 mm), which decreased to

40.50 mm. A sharp decrement in penetration values of polypropylene modified bitumen

blends confirms the hardening effect taking place due to the change in physio-chemical

properties of bitumen after modification (Habib et al., 2015). A decreased penetration

value can possibly favour the resistance of the modified binder against high

temperature-susceptible defects and rutting (Bala et al., 2017).

81
Table 4. 11 Penetration test for the saw samples

Sample Run 1 Run 2 Average

Sunbare 51.27 51.24 51.255

Lado 51.24 51.24 51.24

Agbabu 51.26 51.28 51.27

Abigi 51.27 51.26 51.265

82
Table 4. 12 Penetration test for polymer (Polypropylene) modified Agbabu
Bitumen

S/N Run 1 Run 2 Run 3 Average

1 51.75 51.27 51.24 51.42

2 40.27 38.07 39.7 39.34667
3 42.38 41.61 41.97 41.98667
4 32.31 33.8 34.07 33.39333
5 45.12 44.07 43.74 44.31
6 40.72 48.53 40.1 43.11667
7 44.75 44.46 41.86 43.69
8 37.17 38.58 38.22 37.99
9 36.49 37.01 37.32 36.94
10 34.71 34.67 34.39 34.59
11 38.52 37.05 37.73 37.76667
12 39.45 39.26 39.6 39.43667
13 42.99 42.41 42.24 42.54667
Total Average 40.50256

83
4.7 Physical and mechanical tests for Agbabu Natural Bitumen (ANB) modified
with butyl acrylate (BA) and poly(styrene-co-butadiene) (PSCB)

The temperatures at which bitumen ignites in the presence of an open flame are

known as the flash and fire points. The viscosity, loss of ductility, penetration,

softening, flash, and fire points attained for the improved ANB are shown in Tables

4.13 and 4.14. The bitumen modified with BA has an optimal flash point of 78 °C,

which is lower than the bitumen modified with PSCB, which has an optimal flash point

of 119 °C. The same is true of the fire point, which indicates that PSCB is a superior

modification to BA because it is higher than BA's fire point. The flash points produced

in the experiments are both lower than the 230 °C recommended by the American

Society for Testing and Materials (ASTM, 2010) and the British Standard Institution
(Salawudeen et al., 2020)
(BS, 2000), necessitating the use of a ternary combination .

The penetration test identifies different bitumen grades and is frequently used to

gauge bitumen consistency or hardness (Olugbenga et al., 2012). The penetration point

for virgin Agbabu bitumen is 51.27 mm, as shown in Table 4.11. These results show a

significant decrease in penetration from 51.27 mm (ANB) to 19.60 mm (ANB + BA)

and 10.30 mm (ANB + PSCB), respectively, as compared to those shown in Tables 4.13

and 4.14. This suggests that ANB alone has inadequate load-bearing capacity and might

not be able to support significant traffic loads when used in its pure natural state. The

high specific surface and good tensile properties of PSCB, however, resulted in a

considerable reduction in penetration when used as a modifier. The measured

penetration values of 10.3 for PSCB modifier were similar to the suggested penetration

grade ranges of 8.5 - 10.0 mm in ASTM and BS when the experimental findings were
(Salawudeen et al., 2020)
compared to the standards (ASTM, 2010; BS, 2000) .

84
Table 4. 13 Agbabu Bitumen Modified with Butyl Acrylate
Flash. Point Fire Point Ductility Pen. Point Soft. Point Viscosity
Run Bitumen Polymer (°C) (°C) (cm) (cm) (°C) (mpa/s)
1 96.25 3.75 66.5 80 29.8 3 70 212.55
2 94 6 69 73.5 32.2 2.82 52.5 214.05
3 94 6 - - - - - -
4 98.5 1.5 76 82 58.5 4.43 36 213.8
5 98.5 1.5 - - - - - -
6 98.5 1.5 - - - - - -
7 95.5 4.5 55 64 19.52 1.96 46.5 84.1
8 96.25 3.75 - - - - - -
9 97.375 2.625 78 81 56.8 4.58 62.5 209
10 96.25 3.75 - - - - - -
11 95.125 4.875 66.5 76 25.92 2.68 74 534.8
12 94 6 - - - - - -
13 97 3 65 71.5 28.25 0 76 213.25

86
Table 4. 14 Agbabu Bitumen Modified with Poly(styrene-co-butadiene)
Polyme Flash. Point Fire Point Ductility Pen. Point Soft. Point Viscosity
Run Bitumen r (°C) (°C) (cm) (cm) (°C) (mpa/s)
1 96.25 3.75 77.5 87 0.2 0 77 207.85
2 94 6 119 125.5 0 0 81 211.9
3 94 6 - - - - - -
4 98.5 1.5 74 82 2.7 1.03 72.5 211.05
5 98.5 1.5 - - - - - -
6 98.5 1.5 - - - - -
7 95.5 4.5 85 90 0 0 80.5 215.35
8 96.25 3.75 - - - - - -
9 97.375 2.625 80 86.5 0.4 0.02 74 213.1
10 96.25 3.75 - - - - - -
11 95.125 4.875 102 126.5 0 0 73.5 213.8
12 94 6 - - - - - -
13 97 3 72 84 0.8 0.12 77 212.85

87
 Because bitumen is viscoelastic, it cracks more easily at low temperatures.

Consequently, bitumen's ductility at low temperatures is what defines its cohesiveness.

It is a quality whose value is determined by the bitumen's grade. The ductility point of

the virgin ANB is 24.58 cm, according to Salawudeen et al. The binary mix with BA

had a favorable effect on elongation, increasing the optimal ductility point to 58.50 cm.

The optimal ductility point decreased to 2.70 cm as a result of the binary mix with

PSCB, which had a detrimental effect on elongation. This suggests that BA is a more

effective modifier to raise the ductility test ANB's permissible range

(Salawudeen et al., 2020)
.

Since the bitumen becomes fluid at the softening point, a high softening point is
Salawudeen et al., 2020
preferred (Olugbenga et al., 2012). As reported by , the virgin

ANB has a softening point of 79 °C. The results shown in Table 4.13 and Table 4.14

reveal that ANB modified with BA is softer with optimal softening point of 76 °C than

virgin bitumen and ANB modified with PSCB (81 °C). This could be related to the fact

that BA is a liquid polymer. According to ASTM and BS standards, the minimum

allowable bitumen softening point ranges are 42 – 51 ºC and 55 - 63 ºC. Lower

softening point recorded for ANB modified with BA indicate a better modifier for road

pavement while higher softening points recorded for ANB modified with PSCB indicate

higher grade for the binary mixture, which suggest that ANB with BA will be good for
(Salawudeen et al., 2020)
paving roads .

According to a viscosity test conducted on ANB modified with BA and PSCB at

29.4 °C and 30 rpm, the addition of these polymers to bitumen raises ANB's viscosity

from 150 °C to roughly 200 °C, indicating an increase in resistance to rutting and

thermal cracking at high temperatures. This might be as a result of the polymer's

interaction with the hetero atoms in bitumen, which are slightly more effective in the

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microwave irradiation and prevent the association or dissociation of molecules as

temperature changes.

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 CHAPTER FIVE

CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusions

In line with the set objectives, the following conclusion were drawn from this

research;

Purification of the Nigeria tar sand using solvent extraction techniques

(petroleum ether) produces bitumen with high purity and very easy to carry out thereby

making the modification and characterization result more reliable compare to using

other means for extraction

From the thermogravimetric analysis, it could be inferred that bitumen sample

from Loda had lesser evaporation and higher thermal stability in its raw form than those

from Agbabu, Sunbare and Abigi this is because is losses less weight during the test.

Abigi and Sunbare samples have more metal composition than Agbabu and Loda

samples. This may be due to the fact that the former samples are from the same axis

(Ogun state axis)

Modification that was done on the Agbabu natural bitumen show that there is a

significant decrease in the modified bitumen compared to the unmodified bitumen

thereby indicating that fluidity is decreased and high-temperature consistency of

bitumen is improved. A decreased penetration value can possibly favor the resistance of

the modified binder against high temperature-susceptible defects and rutting.

5.2 Recommendation

Solvent extraction techniques are a very good method of extracting bitumen

from tar sand, but devising a means to recover the solvent from the bitumen with

allowing it losing it to evaporation will be more economical. Other polymers and

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materials should be used for the modification of bitumen. Comparing the modification

characterization will help to know which is best for road pavement at different location

and those that can best be used for other application.

91
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