FOAMED BITUMEN STABILISED SANDSTONE AGGREGATES By Roslinah HAJI ABDUL KARIM Thesis submitted to the University of Nottingham for the degree of Doctor of Philosophy February 2015 ABSTRACT Roads form a key element for the expansion of economy and development of a country. As with most countries, Brunei Darussalam has been facing a rapid development to meet the economic growth that requires an efficient road network. Therefore, the scarcity of conventional road aggregates in Brunei Darussalam means that the country has a strong dependence on imported aggregates from overseas to construct quality roads. Further restrictions on local road specifications make it almost impossible to include low quality granular materials. The study reported in this thesis was undertaken on the basis that the dependence on overseas resources is not a viable long- term solution. The research task has been, therefore, to ascertain the quality of local sandstones for road construction and then to propose means to upgrade their performance quality for optimum utilisation in cost effective applications. This study focused on the road base layer since that is where most aggregate is used. The approach used for this study was to identify the common rock in Brunei Darussalam and review the candidate treatment methods. A weighted matrix for these candidate treatment methods was constructed to determine the overall ranking with selected key criteria on the basis of the local climatic condition, construction preferences and traditions. From the reviews, Foamed bitumen was selected as a feasible treatment method that can improve the sandstone characteristics under local conditions. Three curing conditions were adopted in this study, simulating extreme field conditions in Brunei Darussalam, to characterise the mechanical properties of foamed bitumen stabilised sandstone mixtures, termed (cid:181)(cid:73)(cid:82)(cid:68)(cid:80)(cid:3)(cid:80)(cid:76)(cid:91)(cid:182)(cid:17)(cid:3)(cid:55)(cid:75)e following tests were conducted: (cid:131) The response of stiffness modulus behaviour in the foam mix produced at different levels of mixing moisture content and i cement content under dry and wet conditions was measured to study the mixing moisture content (MMC) in foam mix design. (cid:131) A humid curing study was performed to indicate the short term stiffness of foam mixes in order to aid in the prediction of the delay necessary before a road comprising these foam mixes could be opened to traffic, and to determine how curing time and moisture content affect the development of stiffness modulus with and without cement. (cid:131) A preliminary investigation was carried out into the potential of coir fibres as a reinforcement agent in the foam mix, measuring its effect on stiffness modulus, tensile strength and permanent deformation. (cid:131) Being sensitive to moisture, the climatic durability of foam mix was further assessed by studying the effect of dry/wet cycles on the stiffness modulus incorporating other additives such as hydrated lime and pre-blended bitumen with wet fix. (cid:131) Microscopic analysis has been undertaken as a guide to characterise the microstructure of the foam mix incorporating additives such as cement and coir fibres in order to support the laboratory findings. The laboratory results confirmed that the stiffness behaviour of the foam mix could be influenced by the amount of MMC, cement content and humidity of the environment. It was found that the foam mix with 1% cement (by mass of dried aggregates) at MMC, 70% of OMC, produced a durable mixture with a high stiffness modulus value in both dry and wet conditions as well as when subjected to the effect of alternate dry and wet cycles. The investigation on the potential of coir fibre to reinforce the foam mix indicated that the fibre did help to prevent large cracks in the foam mixes but unfortunately the reinforced foam mixes were easily damaged under a wet environment. ii ACKNOWLEDGEMENT Foremost, I would to express my deepest appreciation to my supervisor, Professor Andrew Dawson for his generous contribution of time, immense knowledge and guidance to keep me going for the entire duration of my study. My deepest thank you to Dr Alessandra Carrera whose advice and insights in the early year of the study has positively contributed to the research and she never hesitated to review my work from time to time when needed. I would like to express my sincere gratitude to Dr Hussein Khalid and Dr Nick Thom for allowing me to exhibit and communicate the significance of my research findings in more effective way. I extend my gratitude to the two former Directors of Roads, Ismail Jaafar, who believes so much in me and, Amer Hishamuddin Zakaria, for putting their trust in me to pursue my study. Sponsorship by the Government of Brunei Darussalam is gratefully acknowledged and my appreciation goes to the Brunei High Commission (Recruitment and Training Section) who were responsible to provide the necessities during my stay in the United Kingdom. Special thank you and deepest appreciation go to the current Director of Roads, Kok On Yee, to whom I am indebted for his continuous motivational words that fuel my determination and perseverance through the difficult times. This thesis work was also made possible by the great assistance of the laboratory technicians, Richard Blakemore, Martyn Barrett, Richard iii Meehan, Nancy Hodge, Lawrence Pont. Jon Watson and Michael Winfield for facilitating and supporting my laboratory works as needed. I am very thankful for the cooperation and assistance rendered by Nigel Neate, for helping on the SEM and the Rock Mechanic Laboratory technicians for their kind help. I gratefully acknowledged the Craig Yr Hesg Quarry for supplying the sandstone aggregates and Total Bitumen Company for its kind support to provide Bitumen throughout the research study period. My eternal love goes to my parents for their devotions in providing good education since the early age; my father who has been the greatest role in shaping my educational path; my mother who has been unconditionally patient and my greatest soul through my years of hardship. Special thank you to all of my family members, my dear sisters and brother for taking care of mum and dad whilst I was away; my dearest Uncle and family for always being there every now and then; my dear late brother-in-law who was a very attentive brother; and the others for their supports particularly through the difficult times. My thank you goes to all my friends who have given the invaluable support and advice through the journey. iv DECLARATION The research reported in this thesis was conducted at the Nottingham Transportation Engineering Centre (NTEC), School of Civil Engineering, University of Nottingham. I declare that the research study is my own and has not been submitted for a degree in another university. Roslinah HAJI ABDUL KARIM The University of Nottingham United Kingdom February 2015 v CONTENTS LIST OF FIGURES xvii LIST OF TABLES xxvii CHAPTER 1 INTRODUCTION 1 1.1 BACKGROUND 1 1.2 PROBLEM STATEMENT 3 1.3 NEED FOR RESEARCH 6 1.4 AIM AND OBJECTIVES 6 1.5 RESEARCH METHODOLOGY 7 1.6 RESEARCH BENEFITS 9 1.7 THESIS LAYOUT 10 CHAPTER 2 REVIEW OF RELEVANT LITERATURE 14 2.1 INTRODUCTION 14 2.2 CLIMATIC CONDITIONS 14 2.3 GEOLOGICAL FEATURES 18 2.3.1 Geology 19 2.3.2 Mineral Resources 21 2.3.3 Geological formations in Temburong District 22 vi 2.3.4 Aggregate Resources 23 2.3.5 Aggregate Statistics Data 26 2.4 ROAD CONSTRUCTION AND DESIGN PRACTICE 30 2.4.1 Pavement Specifications 30 2.4.2 Pavement Design 31 2.4.3 Flexible Pavement configuration 34 2.4.4 Classification of Road 35 2.4.5 Road Length Statistics and Construction Practise 36 2.4.7 Pavement Stabilisation Practise 39 2.5 SUMMARY 40 CHAPTER 3 EVALUATION OF CANDIDATE STABILISATION METHODS 43 3.1 INTRODUCTION 43 3.2 REVIEW OF CANDIDATE STABILISATION METHODS OR AGENTS 44 3.2.1 Mechanical Bonding 44 3.2.2 Cementitious Bonding 47 3.2.3 Bituminous Bonding 48 3.2.4 Polymer Bonding 50 vii 3.2.5 Summary of the Binders 50 3.3 RANKING EVALUATION OF CANDIDATE STABILISATION METHODS OR AGENTS 52 3.3.1 Weighted Matrix 53 3.3.2 Descriptions of Criteria 56 3.4 SCORES AND RANKING 62 CHAPTER 4 REVIEW OF FOAMED BITUMEN MIXTURE 66 4.1 INTRODUCTION 66 4.2 MIX DESIGN CRITERIA FOR FOAMED BITUMEN MIXTURE 66 4.2.1 Granular Materials 67 4.2.2 Foamed Bitumen Binder Content 68 4.2.3 Characteristics of Foamed Bitumen 68 4.2.4 Mixing Moisture Content 71 4.2.5 Other Factors 73 4.3 MECHANICAL PERFORMANCE OF FOAMED BITUMEN MIXTURES 75 4.3.1 Stiffness Modulus 77 4.3.2 Fatigue 81 4.3.3 Permanent Deformation 83 viii 4.4 MOISTURE DAMAGE 85 4.4.1 Aggregate-Bitumen Interactions 87 4.4.2 Treatment in Current Practise 88 4.4.3 Coir Fibres as Reinforcment in Road Materials 89 4.5 FAILURES OF FOAMED BITUMEN APPLICATION 91 4.6 SUMMARY 91 CHAPTER 5 ANALYSIS OF MATERIALS 94 5.1 INTRODUCTION 94 5.2 AGGREGATES 94 5.2.1 Selection 95 5.2.2 Gradation 100 5.2.3 Compaction Methods 105 5.3 BITUMEN 111 5.2.1 Selection 111 5.2.2 Circulated Neat Bitumen and Foamed Bitumen 113 5.3 ADDITIVES 115 5.3.1 Cement 116 5.3.2 Coir Fibres 117 ix