iii
STUDY ON AGEING PROCESS OF POLYMER MODIFIED
BITUMEN
NURUL ‘IZZATI BT AB RAHIM
Thesis submitted in fulfillment of the requirements
for the award of the degree of
Bachelor of Chemical Engineering in Chemical Engineering
Faculty Of Chemical & Natural Resources Engineering
UNIVERSITI MALAYSIA PAHANG
JUNE 2012
viii
ABSTRACT
Bitumen is a very complex combination of organic compound and contain
high proportion of hydrocarbons with high carbon numbers. The main application of
bitumen is in road industry because of its good adhesion to mineral aggregates and its
physical properties. The major failure modes using only bitumen in the road
construction are rutting, cracking and ageing. In cold climates, cracking in pavements
may be an extensive problem. Low temperature cracking is caused by thermally
induced tensile stresses exceeding the tensile strength of the pavement material. By
modified the bitumen using polymer which is Ethylene Vinyl Acetate (EVA) is an
alternative to increase the physical and chemical properties of 80/100 bitumen due to
short term ageing effect. The sample of polymer modified bitumen is prepared using
Toluene as a solvent to bind the polymer with bitumen. The sample then undergoes the
short term ageing process using Thin Film Oven (TFO) before being characterized
using FTIR, Softening Point test, penetrometer, viscometer and TGA. Experimental
results showed that increasing EVA content in the bitumen will reduce the quality of
the bitumen grade, but will improve the performance of bitumen on the environment.
Therefore, the best EVA content to be brought together with bitumen is 2-4%.
ix
ABSTRAK
Bitumen adalah kombinasi yang sangat kompleks terdiri daripada bahan
organik dan mengandungi sebahagian besar hidrokarbon dengan bilangan karbon yang
tinggi. Penggunaan utama bitumen adalah dalam industri penghasilan jalan raya kerana
mempunyai fungsi lekatan yang baik terhadap agregat mineral. Punca kegagalan utama
yang menggunakan bitumen sebagai bahan utama dalam pembinaan jalan raya adalah
keretakan dan penuaan. Keretakan ketika suhu iklim rendah disebabkan oleh tegangan
terma didorong oleh penekanan melebihi kekuatan tegangan bahan turapan. Pengolahan
bitumen menggunakan polimer iaitu Ethylene Vinyl Acetate (EVA) ialah satu alternatif
untuk meningkatkan sifat fizikal dan kimia bitumen grade 80/100 akibat kesan penuaan
jangka pendek. Sampel bitumen yang diolah bersama polimer disediakan menggunakan
Toluene sebagai pelarut untuk menyatukan polimer dan bitumen. Sampel kemudiannya
menjalani proses jangka pendek penuaan menggunakan Thin Film Oven (TFO)
sebelum dianalisis dengan menggunakan FTIR, Analisis Softening point, penetrometer,
Viskometer dan TGA. Hasil uji kaji menujukkan bahawa semakin banyak kandungan
EVA di dalam bitumen akan mengurangkan kualiti grade bitumen tersebut tetapi akan
meningkatkan ketahanan bitumen terhadap persekitaran. Oleh yang demikian,
kandungan EVA yang terbaik untuk disatukan bersama dengan bitumen adalah 2-4%.
x
TABLE OF CONTENTS
Page
SUPERVISOR’S DECLARATION ii
STUDENT’S DECLARATION iii
ACKNOWLEDGMENTS iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES xiv
LIST OF FIGURES xv
LIST OF SYMBOLS xvi
LIST OF ABBREVIATIONS xvii
CHAPTER 1 INTRODUCTION
1.1 Background of Study 1
1.2 Problem statement 2
1.3 Objective of study 3
1.4 Scope of study 3
1.5 Significant of study 4
xi
CHAPTER2 LITERATURE REVIEW
2.1 Bitumen 5
2.1.1 Overview Of Bitumen 5
2.1.2 Application Of Bitumen 6
2.1.3 Properties Of Bitumen 7
2.1.4 Types And Structures Of Bitumen 8
2.2 Polymer 9
2.2.1 Type Of Polymer 9
2.3 Polymer Modified Bitumen 10
2.3.1 Overview Of Polymer Modified Bitumen 10
2.3.2 Interaction Between Polymer And Bitumen 11
2.3.3 Properties Of Polymer Modified Bitumen Using
Ethylene Vinyl Acetate (EVA) 13
2.4 Ageing For Polymer Modified Bitumen 14
2.4.1 Overview Of Ageing Mechanisms 14
2.4.2 Method Of Ageing Process 14
2.4.3 Effect Of Functional Group 15
2.5 Characterization of PMB 16
2.5.1 Fourier Transform Infrared Spectroscopy (FT-IR) 16
2.5.2 Thermagravimetric Analysis (TGA) 16
CHAPTER3 METHODOLOGY
3.1 Introduction 17
3.2 Material 17
3.2.1 Bitumen 17
3.2.2 Ethylene Vinyl Acetate 18
3.2.3 Toluene 19
3.3 Equipment 19
3.3.1 Fourier Transform Infrared Spectroscopy 19
xii
3.3.2 Thin Film Oven 20
3.3.3 Penetrometer 21
3.2.4 Thermogravimetric Analysis(TGA) 22
3.4 Method Of Research 23
3.4.1 Preparation Of Polymer Modified Bitumen 23
3.4.2 Standard Ageing Procedure 25
3.4.3 Analysis Sample 26
3.4.3.1 FTIR Analysis 26
3.4.3.2 Softening Point 26
3.4.3.3 TGA 27
3.5 Research Design 28
CHAPTER4 RESULT AND DISCUSSION
4.1 Introduction 29
4.2 Characterize of PMP on Physical Properties 29
4.2.1 Penetrometer Test 29
4.2.2 Softening Point 31
4.2.3 Penetration Index 33
4.3 Characterize Of PMB On Chemical Properties 34
4.3.1 Fourier Transform Infrared Spectrometry
(FTIR) Analysis 34
4.3.2 TGA Analysis 41
CHAPTER5 CONCLUSION AND RECOMMENDATION
5.1 Conclusion 44
5.2 Recommendation 45
LIST OF REFERENCES 46
APPENDIX 48
xiv
LIST OF TABLES
Table No. Title Page
2.1 Properties PMB using EVA as a polymer 13
3.1 Properties Bitumen 80/100 17
3.2 Properties of EVA 18
3.3 Properties of Toluene 19
4.1 Result on Penetration Test 30
4.2 The value of softening point for each percent EVA in bitumen 31
4.3 The PI before and after ageing process for PMB sample 33
4.4 Wave number (cm–1
) of dominant peak obtained from absorption
spectra and the intensity before ageing 36
4.5 Wave number (cm–1
) of dominant peak obtained from absorption
spectra and the intensity after ageing 39
4.6 TGA result for PMB sample with different EVA content 43
xv
LIST OF FIGURES
Figure No. Title Page
2.1 Global Bitumen Use 6
2.2 Example of broad chemical types present in bitumen 8
2.3 The Microstructure Of Polymer Modified Bitumen 12
2.4 Effect of ageing in bitumen FTIT spectrogram 15
3.1 Thin Film Oven 20
3.2 Penetrometer 21
3.3 Thermogravimetric analysis 22
3.4 Procedure on preparing polymer modified bitumen 24
3.5 Procedure on standard ageing of Polymer Modified Bitumen 25
3.6 Flow diagram of research design 28
4.1 Graft on Penetration Value Versus Percentage of EVA in Bitumen 30
4.2 Graph on Temperature of Softening Point Versus Percentage of EVA
Content 32
4.3 FT-IR wavelength before ageing 35
4.4 FT-IR wavelength after ageing 38
4.5 TGA analysis result 42
xvi
LIST OF SYMBOLS
% Percentage
°C Degree Celsius
xvii
LIST OF ABBREVIATIONS
cm centimeter
cm-1
per centimeter
EVA Ethylene Vinyl Acetate
FT-IR Fourier Transform Infrared Spectrometry
IDT Initial Decomposition Temperature
h hour
L litre
MDT Maximum Decomposition Temperature
mg miligram
ml mililiter
mm milimeter
PI Penetration Index
PMB Polymer Modified Bitumen
rpm revolution per minutes
TFO Thin Film Oven
TGA Thermogravimetric
i
ABSTRACT
Bitumen is a very complex combination of organic compound and contain high
proportion of hydrocarbons with high carbon numbers. The main application of bitumen is in
road industry because of its good adhesion to mineral aggregates and its physical properties. The
major failure modes using only bitumen in the road construction are rutting, cracking and ageing.
In cold climates, cracking in pavements may be an extensive problem. Low temperature cracking
is caused by thermally induced tensile stresses exceeding the tensile strength of the pavement
material. By modified the bitumen using polymer which is Ethylene Vinyl Acetate (EVA) is an
alternative to increase the physical and chemical properties of 80/100 bitumen due to short term
ageing effect. The sample of polymer modified bitumen is prepared using Toluene as a solvent to
bind the polymer with bitumen. The sample then undergoes the short term ageing process using
Thin Film Oven (TFO) before being characterized using FTIR, microstructure analysis,
penetrometer, viscometer and TGA. The increasing of EVA content in bitumen will increase the
viscosity of sample and will reduced the value of penetration.
1
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF STUDY
Bitumen are commonly uses especially in road industry because of their good
adhesion to mineral aggregates and their physical properties (Luo & Chen, 2010).
However, during the last decade increase in axle loads, heavy traffic, severe climatic
conditions and construction failures led to a need to enhance the properties of the base
bitumens. Consequently, the properties of bitumen need to be improved with regard to
performance-related properties such as resistance to permanent deformation, low
temperature cracking, wear, stripping and ageing (Mouillet et al., 2008).
Bitumen is one of the fossil organic material that produce from the bottom of the
vacuum distillation columns in the crude oil refineries (Kebritchi et al., 2010). It’s that will
evolves with time , due to ageing process. It also thermoplastic material and have
important limitations due to their temperature sensitivity (Lamontagne et al., 2001) . Using
bitumen in the construction of asphalt pavements for more than a century will affect many
aspects of road performance (Mouillet et al., 2008).
The specific performance enhancers have been investigated such as polymers in
order to obtain the improved bitumen characteristic and properties. Plenty of polymer can
be used in the preparation of polymer-modifies emulsion such as Ethylene Vinyl Acetate
(EVA), Styrene Butadiene Rubber (SBR) latex, Styrene Butadiene Styrene (SBS),
Polychloroprene latex and natural rubber latex. Using the polymer modified bitumen
2
emulsion present a safer and more environmental friendly binder for enhancing the
properties of roads ( Forbes et al, 2001).
1.2 PROBLEM STATEMENT
The major failure modes using only bitumen in the road construction are rutting,
cracking and ageing. In cold climates, cracking in pavements may be an extensive
problem. Low temperature cracking is caused by thermally induced tensile stresses
exceeding the tensile strength of the pavement material. The degree of cracking may be
influenced by many types of factors, such as material, structure and environmental factors.
For example, mixture of a bitumen need to be flexible at high and low temperature. This to
prevent pavement cracking and rutting (Mouillet et al., 2008).
Bitumen ageing is one of the principle factor causing the deterioration of road
pavements (e.g. Cracking, rutting and the road moisture will damage). Ageing is a very
complex process in conventional bitumens and the complexity increases when polymer
modified bitumens are involved. This ageing is cause by the oxidation process where the
oxygen from the surrounding air .Moreover ageing also causes by the temperature and the
changing of the weather (Lu & Isacsson, 2000).
Using the polymer modified bitumen is an alternative method in order to increase
the bitumen performance. Moreover it can improve in performance durability, mitigation
of pavement distress, and reduced life cycle costs compared to unmodified asphalt
emulsions or hot mix asphalt surface dressings (Lu & Isacsson, 2001).
3
1.3 OBJECTIVES OF STUDY
Based on the research background and problem statement described in the previous
section, the objective of this research to study the ageing process and properties of polymer
modified bitumen
1.4 SCOPE OF RESEARCH
In order to handle the above mentioned objectives, the following scopes were drawn:
a) Preparing the polymer modified bitumen using the toluene as a solvent.
b) Preparing the ageing process of polymer modified bitumen using Thin film Oven
c) The prepared polymer modified bitumen will be characterized by using FTIR ,
Softening Test, Penetrometer and TGA.
4
1.5 BENEFITS AND SIGNIFICANT OF RESEARCH
The rationale and significance of this research is to create a safer and more
environmentally friendly binder for enhancing the properties of road. Besides that the
polymer modified bitumen will offer improvement of the road performance. Using
polymer modified bitumen will help reduce maintenance and the life cycle costs of the
road.
5
5
CHAPTER 2
LITERATURE REVIEW
2.1 BITUMEN
2.1.1 Overview of bitumen
Bitumen is a very complex combination of organic compound and its contain high
proportion of hydrocarbons with high carbon numbers.Bitumen is the residual product
from distillation of crude oil in petroleum refining and produced to meet a variety of
specifications based upon physical properties. The common refining process used for
producing bitumen is straight reduction to grade from petroleum crude oil or blend.
This process is usually using atmospheric and vacuum distillation as major
equipment. Bitumen can be further processed by blowing air through it at elevated
temperatures to alter its physical properties for commercial application (Asphalt
Institute, 2011).
6
2.1.2 Application of Bitumen
According to Asphalt Institute Inc., the current world consumption of bitumen
is approximately 102 Million tonnes per year. Figure 2.1 show the percentage global
bitumen use. At least 34% from 102MT per year bitumen are use in North America,
followed by 30% had been used in Asia and pacific and at least 20% bitumen use in
European Union.
Figure 2.1: Global Bitumen use
From 102 MT/yr consumption of bitumen, 85% of all the bitumen is used as
the binder in various kind of asphalt pavements: pavements for roads, airports,
parking lots, etc. The other 10% of bitumen is used for roofing and the rest of the
bitumen , about 5% of the total is used for a variety of purposes, each very small in
volume. This sector is referred as ‘Secondary Uses’ (Asphalt Institute, 2011).
7
2.1.3 Properties of Bitumen
Bitumen is an organic liquid mixture that is highly viscous, black, sticky,
entirely soluble in carbon disulfide, and composed primarily of highly condensed
polycyclic aromatic hydrocarbons. Bitumen also known as asphalt or tar (Hirst, 2003).
Bitumen are the residual product obtain by fractional distillation of crude oil at the
bottom fraction. Bitumen one of the most complex molecules found in nature and the
one with the highest boiling point.
At ambient temperature in-situ, bitumen is solid and virtually non-volatile and
the vapor pressure of in-situ bitumen is below the limit of detection for normal
instrumentation. Normally bitumen is heated to >140 oC to become liquid to facilitate
transportation and handling (Asphalt Institute, 2011).
8
2.1.4 Types and structures of bitumen functional group
Generally the chemical composition of bitumen is similar, but with some
variation depending upon the original crude oil and on the process used during
refining and blending. Bitumen can be described as complex mixtures containing a
large number of different chemical compounds of relatively high molecular weight.
The molecules contain in bitumen are combinations of alkanes, cycloalkanes,
aromatics and hetromolecules (which is contain sulphur, oxygen, nitrogen and heavy
metals). The significance of molecules containing hetero-atoms in bitumen chemistry
is the ability to form molecular associations, which strongly influence the physical
properties and performance of bitumen.
Functionality of bitumen related on how molecules interact with each other or/and
with aggregate surfaces or/and other materials. Typically, bitumen contains
predominantly cyclic hydrocarbons (aromatic and/or naphthenic) and less quality of
saturated components which are mainly very low in chemical reactivity. Figure 2.2
below show the example of broad chemical types present in bitumen (Asphalt
Institute, 2011).
Figure 2.2: Example of broad chemical types present in bitumen
9
2.2 POLYMER
Polymer is molecules which consist of a long, repeating chain of smaller units that
called monomer. Polymer consist billions of atoms and have the highest molecular weight
among any molecules (Anissimov, 2011).
2.2.1 Type of Polymer
The common polymer that usually use in the bitumen modification are :
i. Plastomers
ii. Elastomers
EVA (Ethylene-Vinyl-Acetate) and PE (Polyethylene) are example of plastromers
and SBS (Styrene-Butadiene-Styrene) is the most used elastomer. Basically, plastomers
will increase the viscosity and stiffness of the bitumen while elastomers will improve the
elastic behavior of the bitumen (Rooijen et al, 2006). These type of polymers usually
provide in the form of pellets or powder which can easily diluted to the required polymer
content by blending with base bitumen by using low to high shear mixers (Sengoz et al,
2009).
10
2.3 POLYMER MODIFIED BITUMEN
2.3.1 Overview of Polymer Modified Bitumen
Polymer modified Bitumen (PMB) is relate to the process for preparation of
polymer and rubber based modified binder which is useful for the construction of roads
catering to heavy traffic and also for the formation of airfields and surfacing. It also
used as interlayer for sealing of cracks, preventive maintenance of flexible and can
delay the reflective cracking (Juno Bitumix Private Limited, 17 Oktober 2011).
Bitumen modified with polymer is a common means of providing resistance
to pavement deformation. Polymer modified bitumen emulsion is on alternative to
improve the pure bitumen performance (Mouillet et al., 2008). It also can improve
resistance in cracking which result in stronger and more durable overlays even in
extreme climatic conditions. Both elastomer and plastomer modified bitumen have
been apply successfully in situations where rutting was a problem with penetration
grade bitumen (up to alimit). However, the bitumen should not be too stiff, because that
may result in brittle asphalt mixtures, which has caused severe cracking failures with
some types of plastomer modified bitumen in practice (Rooijen et al, 2006).
When bitumen is added in a compatible elastomer (such as SBS), it will
absorb the oily fraction from bitumen which causes the polymer swell. After a while,
the swelled polymer starts to dissolve in the bitumen. This physical process takes at
least several hour and can be influenced by the production process and the use of
additives. Meanwhile Plastomersmelt at high temperature and when added to bitumen it
will appear as small droplets that are dispersed in the bitumen. The bigger the volume
of the polymer in the bitumen, the more it will affect the properties of the bitumen
(Rooijen et al, 2006).
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2.3.2 Interaction between polymer and bitumen
The result of the mutual effect of polymer and bitumen are the morphology of
polymer modified bitumen, influenced by bitumen composition, polymer nature and
ratio. Commonly, polymer is insoluble to some degree in the bitumen matrix by
resulting eventually in gross separation of both phase. These phase may become either
continuous phase or dispersed, depending on polymer nature, concentration and ability
to swell with maltene molecules (Eweed, 2011).
In general at lower polymer content the small polymer spheres swollen by
bitumen compatible fractions are spread homogeneously in a continuousbitumen phase.
By increasing polymer contain will resulting a continuous polymer phase. Figure 2.3
below show the microstructure of polymer modified bitumen which contains high
polymer content and low polymer content (Rooijen et al, 2006).
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