Evaluation of Rutting Performance on Hot Mix Asphalt Modified - PDF

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                    UNIVERSITI TEKNOLOGI MALAYSIA

  DECLARATION OF THESIS / UNDERGRADUATE PROJECT PAPER AND
                          COPYRIGHT


    Author’s full name : TAN FIE CHEN

    Date of birth             : 03 JANUARY 1986

    Title                     : EVALUATION OF RUTTING PERFORMANCE

                                  ON HOT MIX ASPHALT MODIFIED WITH

                                  PLASTIC BOTTLES


 Academic Session             :      2008/2009

     I declare that this thesis is classified as:

         CONFIDENTIAL                (Contains confidential information under the
                                     Official Secret Act 1972)*

         RESTRICTED                  (Contains restricted information as specified by
                                     the organisation where research was done)*

         OPEN ACCESS                 I agree that my thesis to be published as online
                                     open access (full text)

     I acknowledged that Universiti Teknologi Malaysia reserves the right as
     follows:

            1. The thesis is the property of Universiti Teknologi Malaysia.
            2. The Library of Universiti Teknologi Malaysia has the right to make
               copies for the purpose of research only.
            3. The Library has the right to make copies of the thesis for academic
               exchange.

                                                             Certified by:




             SIGNATURE                                  SIGNATURE OF SUPERVISOR

            860103-04-5042                           TN. HJ. CHE ROS BIN ISMAIL
 (NEW IC NO. /PASSPORT NO.)                                 NAME OF SUPERVISOR


 Date:      30th APRIL 2009                         Date:    30th APRIL 2009


NOTES    : *If the thesis is CONFIDENTIAL or RESTRICTED, please attach with the
            letter from the organization with period and reasons for confidentiality
            or restriction.
                                                                                                     ii




              “I/We* hereby declare that I/we* have read this thesis and in
            my/our* opinion this thesis is sufficient in terms of scope and
                quality for the award of the degree of Bachelor/Master/
                    Engineering Doctorate/Doctor of Philosophy of
                                   Civil Engineering




       Signature                    :    .........................................................
       Name of Supervisor           :      TN. HJ. CHE ROS BIN ISMAIL
       Date                         :




* Delete as necessary
EVALUATION OF RUTTING PERFORMANCE ON HOT MIX ASPHALT
             MODIFIED WITH PLASTIC BOTTLES




                         TAN FIE CHEN




              A report submitted in partial fulfillment
         of the requirements for the award of the degree of
                   Bachelor in Civil Engineering




                   Faculty of Civil Engineering
                  Universiti Teknologi Malaysia




                           APRIL 2009
                                                                                      ii




I declare that this report entitled “Evaluation of Rutting Performance on Hot Mix
Asphalt Modified with Plastic Bottles” is the result of my own research except as
cited in the references. The report has not been accepted for any degree and is not
concurrently submitted in candidature of any other degree.




               Signature      :      ..……………………..
               Name           :         Tan Fie Chen
               Date           :      ……………………….
                               iii




        Dedicated to
my beloved mother and father
                                                                                  iv




                            ACKNOWLEDGEMENT




       In this column of acknowledgement, firstly I thank God for a smooth and
successful process of preparing this report. Secondly, I wish to express my sincere
gratitude particularly to my supervisor, Hj. Che Ros Bin Ismail for his patience and
kind guidance throughout the period of laboratory work and report writing. Without
the attention and dedicated guidance from my supervisor, this report would not be
successfully completed.


       I am also very thankful to the team of highway laboratory technicians, Mr.
Suhaimi, Mr. Sahak, Mr. Ahmad Adin, Mr. Rahman and Mr. Azman for their
assistance in lending helping hand in the time of needs. In additional, I wish to
extend my sincere gratitude to my best friend, course mates, and others who have
provided assistance at various occasions. I am grateful to my parent for continuous
and faithful support.


       Last, but not the least, I would like to acknowledge each and every person
who have contributed to the success of this report, whether directly or indirectly.
May God bless you in your life journey.
                                                                                       v




                                     ABSTRACT




       Plastic is everywhere in today’s lifestyles. Plastic is now used as packaging
material for a whole range of consumer products in addition to carbonated beverages.
Although Polyethylene Terephthlate (PET) is very useful for us but the disposal of
the waste plastic bottles in large quantities has been a problem and is of great
concern, particularly in our country. One of the solutions to the disposal of plastic
bottles is recycling the plastic bottles into useful products. Re-cycled PET from
drinking bottles may be useful in asphaltic (bituminous) pavements, resulting in
reduced permanent deformation in the form of rutting of the pavement surfacing.
The aim of this study is to evaluate the rut resistance of PET as polymer additives to
asphalt concrete. The objectives also include determining the maximum percentage
of PET as bitumen modifier and comparison the PET modified HMA with
conventional HMA in term of rut resistance. The tests include the determination of
penetration index, Marshall test and three wheel immersion tracking test.            The
maximum plastic content was 7.5% and the optimum bitumen content (OBC) for
ordinary mix was 5.3% while the OBC for PET modified mix was 5.2%. From the
three wheel immersion tracking test, it can be said that PET modified bituminous
binders provide better resistance against permanent deformations due to their low rut
depth and it also contributes to recirculation of plastic wastes as well as to protection
of the environment.
                                                                                vi




                                   ABSTRAK




       Plastik terdapat di mana-mana dalam gaya hidup masa kini. Pada masa kini,
plastik digunakan sebagai bahan pembungkusan untuk semua barangan penguna
terutamanya minuman berkarbonat.      Walaupun Polyethylene Terephthlate (PET)
sangat berguna kepada kita tetapi masalah pembuangan botol plastik dalam kuantiti
yang banyak mendatangkan masalah alam sekitar terutamanya di negara kita. Salah
satu jalan penyelesaian masalah pembuangan botol plastik adalah dengan
menggunakan semula bahan buangan tersebut untuk sesuatu yang lebih berfaedah.
PET kitar semula daripada botol plastik mungkin mendatangkan kebaikan dalam
turapan asfal, seperti mengurangkan kesan perpalohan pada permukaan turapan.
Tujuan kajian ini dijalankan adalah untuk menguji kesan penggunaan PET sebagai
bahan tambah dalam konkrit asfal terhadap perpalohan. Objektif kajian ini adalah
untuk mendapatkan peratus maksimum PET sebagai bahan tambah bitumen dan
pembandingan rintangan perpalohan antara HMA terubahsuai PET dengan HMA
biasa. Ujikaji yang dijalankan ialah penentuan indeks penusukan, ujikaji Marshall,
dan ujikaji jejak tiga roda. kandungan maksimum plastik ialah 7.5% dan kandungan
bitumen optimum untuk campuran biasa adalah 5.3% manakala kandungan bitumen
optimum untuk campuran terubahsuai PET adalah 5.2%. Dari ujikaji jejak tiga roda,
didapati campuran PET ubahsuai mempunyai rintangan yang baik terhadap
perpalohan kerana mempunyai kedalaman perpalohan yang rendah dan ia juga
membolehkan pengitaran plastik untuk memelihara alam sekitar.
                                                              vii




                       TABLE OF CONTENT




CHAPTER                           TITLE                    PAGE


          DECLARATION                                         ii
          DEDICATION                                          iii
          ACKNOWLEDGEMENT                                     iv
          ABSTRACT                                            v
          ABSTRAK                                             vi
          TABLE OF CONTENTS                                   vii
          LIST OF TABLES                                      xii
          LIST OF FIGURES                                    xiv
          LIST OF ABBREVIATIONS                              xvi
          LIST OF APPENDICES                                xviii


  1       INTRODUCTION                                        1
          1.1   General                                       1
          1.2   Problem Statement                             2
          1.3   Objectives of the Study                       3
          1.4   Scope of the Study                            3
          1.5   Importance of the Study                       4


  2       LITERATURE REVIEW                                   5
          2.1   Introduction                                  5
          2.2   Hot Mix Asphalt                               6
                2.2.1 Introduction                            6
                2.2.2 Basic Materials in Hot Mix Asphalt      7
                       2.2.2.1 Aggregate                      7
                                                              viii

                2.2.2.2 Asphalt Binder                        8
                2.2.2.3 Mineral Filler                        8
      2.2.3 Gradation Specification for Asphaltic Concrete    9
2.3   Rutting                                                 10
      2.3.1 Introduction                                      10
      2.3.2 Cause of Rutting                                  10
      2.3.3 Mechanism of Rutting                              11
      2.3.4 Example of Others Tests Related to Rutting        12
                2.3.4.1 Georgia Loaded Wheel Tester           12
                2.3.4.2 Asphalt Pavement Analyzer             13
                2.3.4.3 Hamburg Wheel-Tracking Device         14
                2.3.4.4 Superfos Construction Rut Tester      15
                2.3.4.5 LCPC (French) Wheel Tracker           15
                2.3.4.6 Purdue University Laboratory Wheel
                       Tracking Device                        16
                2.3.4.7 Model Mobile Load Simulator (MMLS3)   17


2.4   Polymer Modified Asphalt                                18
      2.4.1 Introduction                                      18
      2.4.2 The Purpose of Asphalt Modification               19
      2.4.3 Binder Modification                               19
      2.4.4 Types of Asphalt Modifiers                        20
      2.4.5 The Ideal Modified Binder                         22
2.5   Waste Material-Polyethylene Terephthalate               23
      2.5.1 Introduction                                      23
      2.5.2 Waste Product as Materials in Highway
                Construction                                  23
                2.5.2.1 Polyethylene Terephthalate (PET)      23
2.6   Polymer Characteristic                                  24
2.7   Compaction                                              25
      2.7.1 Introduction                                      25
      2.7.1 Factor Affecting Compaction                       25
2.8   Three Wheels Immersion Tracking Machine                 25
      2.8.1 Introduction                                      26
                                                               ix

           2.8.2 Wheel Tracking Apparatus                     26
    2.9    Past Performance of Modified HMA Towards Rutting   27


3   METHODOLOGY                                               29
    3.1    Introduction                                       29
    3.2    Laboratory Test Procedure                          30
    3.3    Information Collection                             32
    3.4    Material Collection                                32
    3.5    Sieve Analysis                                     32
           3.5.1 Introduction                                 32
           3.5.2 Procedures of Sieve Analysis                 33
    3.6    Blending of Specimen                               34
    3.7    Penetration Test                                   35
    3.8    Softening Point                                    36
    3.9    Penetration Index                                  37
    3.10   Marshall Test                                      38
           3.10.1 Preparation of Compacted Specimen           39
           3.10.2 Determination of Bulk Specific Gravity
                  of the Specimen                             40
           3.10.3 Marshall Stability and Flow Test            41
           3.10.4 Theoretical Maximum Specific Gravity        42
           3.10.5 Analyzing Marshall Tests Results            43
           3.10.6 Determination of Optimum Bitumen
                  Content at Variation Plastic Content        44
    3.11   Mixing of Specimens                                46
           3.11.1 Introduction                                46
           3.11.2 Method of Sample Mixing                     46
    3.12   Compaction                                         47
    3.13   Three Wheel Immersion Tracking Test                48
           3.13.1 Introduction                                48
           3.13.2 Procedure of the Three-Wheel Immersion
                  Tracking Machine Test                       48
    3.14   Data Analysis                                      49
                                                                x

4   RESULT AND DATA ANALYSIS                                   51
    4.1   Introduction                                         51
    4.2   Sieve Analysis and Aggregate Distribution            52
    4.3   Bitumen Test                                         52
          4.3.1 Penetration Test                               52
          4.3.2 Softening Point Test                           53
          4.3.3 Penetration Index                              54
                 4.3.3.1 Maximum Plastic Content               55
    4.4   Specific Gravity of Bitumen                          55
    4.5   Theoretical Maximum Specific Gravity                 56
    4.6   Marshall Test Analysis                               56
          4.6.1 Optimum Bitumen Content                        57
                 4.6.1.1 Control Sample                        57
                 4.6.1.2 AC14 with 2.5% of PET Added           58
                 4.6.1.3 AC14 with 5.0% of PET Added           58
                 4.6.1.4 AC14 with 7.5% of PET Added           59
                 4.6.1.5 Conclusion of Variations Plastic
                    Content Added                              60
    4.7   Result of Three Wheels Immersion Tracking Test       60
          4.7.1 Introduction                                   60
          4.7.2 Analysis of the Three Wheels Immersion
                 Tracking Test                                 62
                 4.7.2.1 Conventional Sample                   62
                 4.7.2.2 PET Modified AC14                     63
                 4.7.2.3 Conclusion of Three Wheel Immersion
                         Tracking Test                         64
    4.8   Result of Degree of Compaction                       65


5   CONCLUSION AND RECOMMENDATION                              66
    5.1   Introduction                                         66
    5.2   Objective’s Evaluation                               66
          5.2.1 First objective: To determine the maximum
                 percentage of PET as bitumen modifier         67
          5.2.2 Second objective: To compare modified
                                                                      xi

                         HMA with PET and conventional HMA in
                         term of rut resistance                      67
            5.3    Conclusion                                        68
            5.4    Recommendation                                    69


REFERENCES                                                           70
Appendices A – H                                                75 - 105
                                                                             xii




                             LIST OF TABLES




TABLE NO.                            TITLE                                 PAGE


2.1         Gradation Limit for Asphaltic Concrete (JKR, 2005)               9

2.2         Generic types of asphalt modifiers currently used for paving
            Applications                                                     21

3.1         Gradation Limit for Asphaltic Concrete (JKR, 2005)               35

3.2         Minimum sample size requirement for Theoretical Maximum
            Specific Gravity (ASTM D 2041)                                   42

3.3         Group of Variation OBC with Variation Plastic Content            44

3.4         Test and Analysis Parameters for Asphaltic concrete (JKR, 2005) 45

3.5         Sample table for data recording and calculation                  49

4.1         Summary of PI Result                                             54

4.2         The Marshall Mix Design                                          56

4.3         Summary of Marshall Result for Control Sample                    57

4.4         Summary of Marshall Result for AC14 with 2.5% of PET Added       58

4.5         Summary of Marshall Result for AC14 with 5.0% of PET Added       59

4.6         Summary of Marshall Result for AC14 with 7.5% of PET Added       59

4.7         Optimum Bitumen Content of Variation PET Content                 60

4.8         Summary of Three Wheels Immersion Test                           61

4.9         Summary of Air Voids                                             63

4.10        Summary of test result                                           65
                                         xiii

4.11   Summary of Degree of Compaction   65
                                                                             xiv




                              LIST OF FIGURES




FIGURE NO.                             TITLE                               PAGE


2.1          Effect of Wheel Loading Repetitions on Permanent
             Deformation Profile (after Eisenmann and Hilmer 1987)           11

2.2          Georgia Loaded Wheel Tester (GLWT)                              13

2.3          Asphalt Pavement Analyzer (APA)                                 14

2.4          Hamburg Wheel Tracking Device (HWTD)                            14

2.5          Superfos Construction Rut Tester (SCRT)                         15

2.6          LCPC (French) Wheel Tracker (FRT)                               16

2.7          Purdue University Laboratory Wheel Tracking Device
             (PURWheel)                                                      17

2.8          Model Mobile Load Simulator (MMLS3)                             18

2.9          Temperature susceptibility of an ideal thermoplastic binder
             (Usmani, 1997)                                                  22

3.1          Flow of test to be conducted                                    31

3.2          Sieve Shaker                                                    34

3.3          Penetration Test Equipment                                      36

3.4          Nomograph for bitumen penetration index                         38

3.5          Bituminous Laboratory Mixer                                     47

3.6          Three Wheel Tracking Immersion Machine                          49

4.1          Penetration Test Result                                         53

4.2          Softening point Test Result                                     54
                                                          xv



4.3   Maximum Plastic Content                             55

4.4   Rut Depth for Control Sample and Modified AC14      61

4.5   Rutting Rate for Control Sample and Modified AC14   62
                                                                          xvi




                   LIST OF ABBREVIATIONS




AASHTO     -   American Association of State Highway and Transportation
               Officials
AC         -   Asphaltic Concrete Wearing Course
APA        -   Asphalt Pavement Analyzer
ASTM       -   American Society for Testing and Material
FRT        -   French Rutting Tester
GLWT       -   Georgia Loaded Wheel Tester
HMA        -   Hot Mix Asphalt
HWTD       -   Hamburg Wheel Tracking Device
JKR        -   Jabatan Kerja Raya
MMLS3      -   Model Mobile Load Simulator
MRP        -   Malaysia Rock Product Sdn. Bhd.
OBC        -   Optimun Bitumen/Binder Content
P          -   Penetration
PET        -   Polyethylene Terepthalate
PI         -   Penetration Index
PURWheel   -   Purdue University Laboratory Wheel Tracking Device
SCRT       -   Superfos Construction Rut Tester
SG         -   Specific Gravity
SGagg      -   Aggregate’s Specific Gravity
SGbit      -   Bitumen’s Specific Gravity
SGmax      -   Maximum Specific Gravity
SP         -   Softening Point
UTM        -   Universiti Teknologi Malaysia
VFB        -   Voids Filled with Bitumen
VIM        -   Voids in the Mix
%Agg       -   Percentage of Aggregate
                                         xvii

%Air Void   -   Percentage of Air Void
%bit        -   Percentage of bitumen
                                                                 xviii




                         LIST OF APPENDICES




APPENDIX                          TITLE                         PAGE


A1         Distribution of Mass Aggregate for Control Sample
           AC14 Mixture at Optimum Bitumen Content 5.3%            76

A2         Distribution of Mass Aggregate for AC14 Mixture at
           Optimum Bitumen Content 5.2% and Maximum Plastic
           Content 7.5%                                            77

B1         Bitumen Consistency Test Result                         78

B2a-B2e    Nomograph for Bitumen Penetration Index              79-83

C          Theoretical Maximum Specific Gravity                    84

D1-D4      Marshall Test Result                                 85-96

E1a        Three Wheels Immersion Tracking Machine’s Result
           for Control Sample                                      95

E1b        Rutting Rate for Control Sample                         95

E2a        Three Wheels Immersion Tracking Machine’s Result
           for AC14 with Maximum Plastic Content                   98

E2b        Rutting Rate for Modified AC14                          99

F          Degree of Compaction                                  100

G1         Air Voids Content                                      101

G2         Examples Calculation of the Air Void Contents
           in Control Sample                                      102

G3         Examples Calculation of the Air Void Contents in
           PET Modified Sample                                    101

H1         Marshall Samples                                       103
                                           xix



H2   Bulk Specific Gravity                103

H3   Marshall Stability and Flow Test     103

H4   Preparation of Rutting Sample        104

H5   Compaction of Rutting Sample         104

H6   Conducting Rutting Test              105

H7   Rutting Samples                      105

H8   Determination Degree of Compaction   105
                                      CHAPTER 1




                                 INTRODUCTION




1.1    General


       In recent years, the amount of waste plastic bottles being generated had
becomes a serious problem to our environment. Polyethylene Terephthalate (PET)
plastic is now used as a packaging material for a whole range of consumer products
in addition to carbonated beverages. Although PET is very useful for us but the
disposal of the waste plastic bottles in large quantities has been a problem and is of
great concern, particularly in our country.


       One of the solutions to the disposal of plastic bottles is recycling the plastic
bottles into useful products.     According to Flynn (1993), re-cycled PET from
drinking bottles may be useful in asphaltic (bituminous) pavements, resulting in
reduced permanent deformation in the form of rutting and reduced low - temperature
cracking of the pavement surfacing.


       Besides, asphalt concrete mixtures have been exposed to greater stresses
because of the increasing traffic volumes, truck traffic and higher tire pressures. One
of the most common forms of distress of asphalt concrete pavements is rutting
(permanent deformation). Rutting is the defined as the progressive accumulation of
permanent deformation of each layer of the pavement structure under repetitive
loading (Balghunaim et al., 1988).
                                                                                     2

       It has been possible to improve the performance of bituminous mixes used in
the surfacing course of road pavements. The addition of polymers typically increases
the stiffness of the bitumen and improves its temperature susceptibility. Increased
stiffness improves the rutting resistance of the mixture in hot climates and allows the
use of relatively softer base bitumen, which in turn, provides better low temperature
performance (Awwad and Shbeeb, 2007).


       Lastly, the additives polymer in asphalt has been shown to improve
performance of the pavement. Pavement with polymer modification exhibits greater
resistance to rutting and thermal cracking, and decreased fatigue damage, stripping
and temperature susceptibility (Robinson, 2004).




1.2    Problem Statement


       Permanent deformation, or rutting, is a primary failure mode of hot-mix
asphalt (HMA) pavements. Ruts occurring in the wearing course of asphalt concrete
seem to cause a more serious problem in pavement. This failure mode results in a
loss of serviceability of the HMA pavement, and can pose certain safety risks as well.
In consideration of increased traffic loads and in order to improve pavement
performance, polymer- modified asphalts (PMA) have been developed during the last
few decades (Whiteoak, 1990).


       In recent years, numerous waste materials result from manufacturing
operations, service industries and households.      The growth in various types of
industries together with population growth has resulted in enormous increase in
production of various types of waste materials. The creation and disposal of non-
decaying waste materials such as blast furnace slag, fly-ash, steel slag, scrap tyres,
plastics, etc. have been posing difficult problems in developed as well as in
developing countries (Schroeder, 1994). One solution to this crisis is recycling waste
into useful products.
                                                                                       3

       In addition, the use of plastic bottle as container for the soft drink and mineral
water for all brands has become a common practice all over the country. However
the disposal of the waste plastic bottles in large quantities has been a problem and is
of great concern, particularly in big cities.       To overcome this situation, the
engineering analysis was conducted to investigate the possible use of waste plastic
bottles as the modifier of hot-mix asphalt and to review the feasibility of the
recycling technology for waste PET and certain polymers added into asphalt binders
to improve the performance of asphalt concrete.


       In this study, the focuses are to determine the maximum percent Polyethylene
Terephthalate modified in the hot-mix asphalt and comparison of PET modified
HMA with conventional HMA in term of rut resistance.




1.3    Objectives of the Study


       The aim of this study is to evaluate the rutting performance on modified hot
mix asphalt with PET. In this study, the use of PET to modify asphalt mix properties
will be investigated. To achieve this aims, the study is carried out for the following
objectives:
       i.      To determine the maximum percentage of Polyethylene Terephthalate
               as bitumen modifier.
       ii.     To compare the PET modified HMA with conventional HMA in term
               of rut resistance




1.4    Scope of the Study


       The scope of study is focus on evaluation of rutting performance on hot mix
asphalt modified with plastic bottles. The mix will be prepared is AC14 (Asphaltic
Concrete for Wearing Course 14). Rutting will be evaluated using Three Wheel
Immersion Tracking Machine.
                                                                                     4

       In this study, the quantity of additives plastic bottle that will be used in hot
mix asphalt is 0%, 2.5%, 5.0%, 7.5% and 10.0% by weight of the binder (asphalt).
The rut depth of the mixtures will be evaluated by means of the Three Wheel
Immersion Tracking Machine.




1.5    Importance of the Study


       The world transportation is dynamic and it is expanding over the time. Road
defects such as rutting are one of the most dangerous forms of distress in the
pavement because it permits water to pond in the wheel path, which leads to
hydroplaning and an increase in vehicle accidents. In order to improve the service
life of the road towards the dynamic changes of the world transportation, polymer
modified asphalt has become a fact of life for the road construction industry.


       Besides, the additive Polyethylene Terephthalate in asphalt is to avoid
environmental problems resulting from plastic bottles disposal.       By using waste
polymers to modify the asphalt proved to be an ideal way, not only for solving the
pollution problem in our country, but also for improving the performance of asphalt
(Amjad et al., 1999).      From this study, we can observe the performance of
Polyethylene Terephthalate modified asphalt mix in the AC14 samples.
                                                                                    5




                                   CHAPTER 2




                             LITERATURE REVIEW




2.1    Introduction


       Asphalt pavements are composite materials consisting of interspersed
aggregates, asphalt binder, and air voids. Their constitutive behavior is defined by
interaction of these constituents. The load-carrying behavior and resulting failure of
such materials depends on many mechanisms that occur at the constituent level.


       During the past several years many states experienced problems with amount
and severity of permanent deformation in hot mix asphalt pavements. This problem
with permanent deformation, or rutting, was attributed to an increase in truck tire
pressures, axle loads, and volume of traffic (Brown and Cross, 1992).


       Besides, traffic loading repetitions effect on hot mix asphalt (HMA) cause
permanent deformation (rutting) that is considered being one of the most important
pavement distresses. The use of modifiers to improve the performance of asphalt and
aggregate mixtures has been employed in the highway industry from almost the first
use of hot mix asphalt. Modifiers take many different forms. Many modifiers change
the properties of the asphalt binder. These modifiers include: polymers, latex, and
many chemical additives (Awwad and Shbeeb, 2007)


       It is well known that the addition of certain polymer to asphalt binders can
improve the performance of road pavements.           Plastic bottle also known as
                                                                                  6

Polyethylene Terephthalate (PET) has been found to be one of the most effective
polymer additives by virtue of its low glass transition temperature and
semicrystalline (Kulog lu, 1999).       With the combination of polyethylene and
plastomer for the modified hot-mix asphalt, the rutting of the pavement under heavy
loads can be reduced. In this study, the aspect need to evaluate is hot-mix asphalt
modified with plastic bottle on rut resistance.




2.2    Hot Mix Asphalt


2.2.1 Introduction


       Asphalt pavements typically provide excellent performance and value. They
are smooth, quiet and durable. They do not require long construction times and they
are easy to maintain resulting in minimal traffic delays (Walker and Buncher, 1999).
Asphalt surfaced roads subjected to heavy traffic in hot climates may experience
early failures in the form of rutting. The rutting failures are the result of heavy
truckloads with high tire pressures and high pavement temperatures. So, by careful
selection of asphalt binder and aggregate combination will help in providing
optimum performing Hot Mix Asphalt (HMA) pavements.


       Hot mix asphalt is the most popular mix around the world. It is composed of
aggregate (both coarse and fine materials, typically a combination of different size
rock and sand) and liquid asphalt cement (AC) which binds with the aggregate. Hot-
mix asphalt is produced by heating the asphalt binder to decrease its viscosity, and
drying the aggregate to remove moisture from it prior to mixing. The components
are heated and mixed at a central plant and placed on the road using an asphalt
spreader.
                                                                                 7

2.2.2 Basic Materials in Hot Mix Asphalt


       The components of asphalt concrete include as aggregate and asphalt binder.
Mineral filler is sometimes added to hot mix asphalt concrete.




2.2.2.1 Aggregate


       According to Jabatan Kerja Raya (2005), aggregate for asphaltic concrete
shall be a mixture of coarse and fine aggregates, and mineral filler.


       Coarse aggregate shall be screened crushed hard rock, angular in shape and
free from dust, clay vegetative and other organic matter, and other deleterious
substances. The coarse aggregate conformed to physical and mechanical quality
requirements which are:
       i.      The Los Angeles Abrasion Value shall not be more than 25% (ASTM
               C 131);
       ii.     The weighted average loss of weight in the magnesium sulphate
               soundness test of 5 cycles shall not be more than 18% (AASTHO T
               104);
       iii.    The flakiness index shall not be more than 25% (MS 30);
       iv.     The water absorption shall not be more than 2% (MS 30); and
       v.      The polished stone value shall not be less than 40% for only
               applicable to aggregate for wearing course (MS 30).


       Fine aggregate shall be clean screened quarry dusts. It shall be non-plastic
and free from clay, loam, aggregation of material, vegetation and other organic
matter, and other deleterious substances. The fine aggregate conformed to physical
and mechanical quality requirements which are:
       i.      The sand equivalent of aggregate fraction passing the No. 4 (4.75mm)
               sieve shall not be less than 45% (ASTM D 2419);
       ii.     The fine aggregate angularity shall not be less than 45% (ASTM C
               1252);
                                                                                      8

       iii.    The Methylene Blue value shall not be more than 10mg/g (Ohio
               Department of Transportation Standard Test Method);
       iv.     The weighted average loss of weight in the magnesium sulphate
               soundness test of 5 cycles shall not be more than 20% (AASTHO T
               104); and
       v.      The water absorption shall not be more than 2% (MS30).




2.2.2.2 Asphalt Binder


       The asphalt binder component of an asphalt pavement typically makes up
about 5 to 6 percent of the total asphalt mixture, and coats and binds the aggregate
particles together. Asphalt cement is used in hot mix asphalt. Liquid asphalt, which
is asphalt cement dispersed in water with the aid of an emulsifying agent or solvent,
is used as the binder in surface treatments and cold mix asphalt pavements. The
properties of binders are often improved or enhanced by using additives or modifiers
to improve adhesion (stripping resistance), flow, oxidation characteristics, and
elasticity. Modifiers include oil, filler, powders, fibres, wax, solvents, emulsifiers,
wetting agents, as well as other proprietary additives (AASTHO, 1993).




2.2.2.3 Mineral Filler


       Mineral filler consists of very fine, inert mineral matter that is added to the
hot mix asphalt to improve the density and strength of the mixture. It shall be
incorporated as part of the combined aggregate gradation and it shall be of finely
divided mineral matter of limestone such as limestone dust or hydrated lime. Not
less than 70 percent by weight shall pass 0.075 mm (No. 200) sieve. The total
amount of mineral filler shall limited such that the ratio of the combined coarse
aggregate, fine aggregate and mineral filler of final gradation passing 0.075mm sieve
of bitumen, by weight shall be in the range of 0.6 to 1.2. The mineral filler shall also
be treated as an anti-stripping agent (JKR, 2005).
                                                                                       9

2.2.3 Gradation Specification for Asphaltic Concrete


       An aggregate's particle size distribution, or gradation, is one of its most
influential characteristics. In hot-mix asphalt, gradation helps determine almost every
important property including stiffness, stability, durability, permeability, workability,
fatigue resistance, frictional resistance and resistance to moisture damage (Chen and
Liao, 2002). Gradation is usually measured by a sieve analysis. In a sieve analysis, a
sample of dry aggregate of known weight is separated through a series of sieves with
progressively smaller openings. Once separated, the weight of particles retained on
each sieve is measured and compared to the total sample weight. The information in
Table 2.1 indicates that gradation limit for the asphaltic concrete (JKR, 2005).


           Table 2.1: Gradation Limit for Asphaltic Concrete (JKR, 2005)
                    Mix Type                         Wearing Course
                 Mix Designation                          AC 14
               BS Sieve Size, mm             Percentage passing (by weight)


                       28.0
                       20.0                                 100
                       14.0                               90-100
                       10.0                                76-86
                        5.0                                50-62
                       3.35                                40-54
                       1.18                                18-34
                      0.425                                12-24
                      0.150                                6-14
                      0.075                                 4-8
                                                                                 10

2.3     Rutting


2.3.1 Introduction


        Rutting is known as longitudinal depressions, which follow the line of the
wheel paths. The deterioration of pavement due to rutting is a major problem on
heavily travelled flexible pavement specifically on climbing lanes. It is caused by
permanent deformation due to traffic loading in one or more pavement layers. It is
generally irregular and leads to decrease in riding quality. This deterioration may
occur due to lateral plastic deformations especially in high temperature in unstable
wearing course or subgrade soil (O’Flaherty, 1988).         Brown and Cross, (1989)
concluded that the phenomena of rutting are an accumulation of permanent
deformations and it is confined to the top layers of the pavement. These permanent
deformations in the wearing course layer could be developed due to densification and
plastic flow of this layer.




2.3.2 Cause of Rutting


        Permanent deformation (rutting) in asphalt pavements manifests itself as
depressions along the wheel paths as shown in Fig. 2.1. According to the National
Cooperative Highway Research Program (Witczak, 1998), permanent deformation
was selected as the most serious problem for highways and runways in the United
States among all the distresses in asphalt pavements. Fatigue cracking was rated the
second most serious problem, followed by thermal cracking.


        Deformation in hot-mix asphalt is a complex phenomenon where aggregate,
binder, and aggregate-binder interface properties control overall performance. These
properties change over time until the mix reaches the end of its design life.