Dissertations / Theses on the topic 'Bitumen'

Le but de ce travail est d’étudier le potentiel d’un bitume naturel (BN) extrait en Albanie pour la production des bitumes durs (BD) et des enrobés à module élevé (EME). Pour la production des BD, différentes techniques de raffinage du pétrole existent. Néanmoins, avec certains bruts pétroliers il est impossible de les fabriquer. De plus, les BD de raffinerie comportent souvent des défauts qui limitent leurs applications. Ces raisons, couplées à des questions d’approvisionnement, conduisent à chercher des méthodes de substitution. Dans ce contexte, il est intéressant d’utiliser des BN. Cette étude a montré que le BN d’Albanie donne des BD et des EME en conformité avec la Normalisation Européenne, résistants au vieillissement et performants aux basses températures. Un dosage adéquat permet de formuler des matériaux d’une dureté désirée en réponse des exigences techniques des applications routières visées tout en facilitant la gestion des stocks de bitumes dans les centrales d’enrobages
The aim of this thesis is to study the potential of a natural bitumen (NB) mined in Albania in the production of hard bitumens (HB) and that of high modulus asphalt concrete (HMAC). Various petroleum refining techniques are available for the production of HB. Nevertheless, this is impossible with some crude oils. In addition, HB from refineries often present shortcomings which limit their applications. These reasons, coupled with practical issues related to HB supply, motivate the research of alternative methods. In this industrial context it is interesting to use NB. This study has shown that the Albanian NB provides HB and HMAC in accordance with European Standards, resistant to aging and relatively performant at low temperatures. The proper dosage of this NB allows the formulation of materials of desired properties, in response to the technical requirements of the considered road applications, facilitating in this way the use of bitumen stocks in asphalt concrete production plants

In the oil sand industry, bitumen is separated from sands by aerating the heavy oil so that it can float out of a flotation vessel, leaving the unaerated sands behind. A bubble-against-plate apparatus equipped with a high-speed camera has been developed to record the optical interference patterns of the wetting films formed on a flat surface and subsequently obtain the temporal and spatial profiles of the films offline using the Reynolds lubrication theory. The technique has been used to study the interaction mechanisms between air bubbles and bitumen. It has been found that the film thinning kinetics increases in the order of asphaltene, bitumen, and maltene, and that the kinetics increases sharply with increasing temperature. In addition to obtaining kinetic information, the temporal and spatial profiles of the wetting films have been used to derive appropriate hydrodynamic information that can be used to determine the disjoining pressures (∏) in the wetting films. The results obtained in the present work show that ∏ < 0 for maltene and bitumen, while ∏ > 0 for asphaltene at temperatures in the range of 22 to 80 °C. The disjoining pressure data have been analyzed by considering the contributions from the hydrophobic and steric forces in addition to the classical DLVO forces. It has been found that the hydrophobic force increases with increasing temperature, which corroborates well with contact angle data. Dynamic contact angle measurements show that air bubbles attach on bitumen with relatively small contact angles initially but increase sharply to >90° . The extent and the kinetics of contact angle change increase sharply with increasing temperature. These findings suggest that the primary role of temperature may be to increase iii bitumen hydrophobicity and hence hydrophobic force, which is the driving force for bubblebitumen interaction. A thermodynamic analysis carried out on the basis of the Frumkin-Derjaguin isotherm suggests that the disjoining pressure will remain positive (and hence no flotation) until the hydrophobic force becomes strong enough (due to temperature increase) to overcome the positive disjoining pressure created during the course of bitumen liberation.
Ph. D.

La construction des routes avec des techniques d'enrobage à chaud (T=160 °C) implique une consommation d'énergie fossile et des rejets de gaz à effet de serre importants. Une production plus écologique du bitume nécessite de diminuer les températures d'enrobage en conservant les propriétés mécaniques des enrobés ainsi obtenus. Le développement de techniques permettant de réduire les températures est donc un enjeu majeur de l'industrie routière. Dans ce travail, nous avons joué à la fois sur la composition et le procédé pour moduler les propriétés du bitume et atteindre l’objectif fixé.Nous avons décomposé le bitume en ses différentes fractions en utilisant des techniques de séparation asphaltènes/maltènes à l'aide d'un alcane (pentane et heptane). Nous avons formulé des bitumes à différentes proportions et natures d'asphaltènes en introduisant des protocoles de préparation originaux. A l’aide de techniques de caractérisation variées telles que la rhéologie, la diffusion des rayons X ou encore des techniques de microscopies et d'analyses thermiques, nous avons déterminéles rôles des différentes fractions du bitume. Nous avons ainsi montré l'impact important des asphaltènes, mais également des fractions que nous avons qualifiées « d'intermédiaires », sur les comportements rhéologiques. Enfin, nous avons élaboré des objets coeur-écorce, composés d’une écorce rigide, non collante, riche en asphaltènes et d’un coeur mou, riche en maltènes. Ces objets sont particulièrement intéressants pour le transport du bitume à température ambiante
The classic manufacture of hot mix asphalt for road construction is associated with a high consumption of fossil fuels and a high level of emissions of greenhouse gases into the atmosphere. A cleaner production of bitumen requires lowering the manufacturing temperature of these products without impoverishing their level of mechanical performances. The development of technologies that enable temperature reduction had thus become a major objective in the field of road engineering. In this work, we are playing on both composition and process in order to control the final properties of the material and propose an interesting way to reduce temperature during transportation. We have been interested in the different fractions composing the bitumen. We have there by employed a separation technique with alkane (heptane and pentane) to segregate the maltenes and asphaltenes. We could therefore realize diverse reconstituted bitumen using original protocols. Using various characterization techniques (such as rheology, X-ray scattering, optic, electronic and atomic force microscopy, infrared spectroscopy, thermal analysis...), we get insight into the effect of asphaltenes content and nature on bitumen properties. Our results show the huge impact of asphaltenes and other fractions called "intermediate fractions" on bitumen rheological properties. Finally, we propose an innovative processing of bitumen via the elaboration of core/shell objects composed of a rigid, nonsticky and asphaltenes-rich corona and a soft maltenes-rich core. These objects are very interesting for transporting bitumen at ambient temperature

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 'foam mix'. The following tests were conducted: • The response of stiffness modulus behaviour in the foam mix produced at different levels of mixing moisture content and cement content under dry and wet conditions was measured to study the mixing moisture content (MMC) in foam mix design. • 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. • 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. • 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. • 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.

Le recyclage des matériaux routiers constitue une voie de développement durable qui présente des bénéfices en termes de consommation d’énergie et de ressources non renouvelables. Pour mieux prédire les propriétés finales de ces matériaux, la compréhension des phénomènes de mélange intervenant lors de la fabrication des enrobés à chaud et à tiède en centrale d’enrobage est indispensable. L’objectif de la thèse est donc de comprendre et d’identifier les facteurs influençant les phénomènes de mouillage, de remobilisation et de miscibilité des liants bitumineux. Pour cela, la démarche d’étude choisie consiste à étudier les interactions locales entre les constituants organiques et inorganiques du mélange selon une approche physico-chimique aux interfaces et interphases. Concernant le mouillage, des indicateurs ont été sélectionnés pour suivre son évolution à l’interface bitume/roche polie. L’influence du vieillissement du liant a aussi été prise en compte. La viscosité et le taux d’asphaltènes des bitumes ainsi que la composition de surface du substrat minéral influencent la qualité de mouillage. Les résultats ont montré que les évolutions étaient régies par un modèle applicable aux surfaces polies, poreuses et chimiquement hétérogènes. La remobilisation du liant vieilli (à température réduite) par le liant d’apport (chauffé à 160°C) a été étudiée à l’interface et à l’interphase sur des échantillons « bitume d’apport/bitume vieilli ». A l’interface, le temps d’étalement est influencé linéairement par la viscosité du liant vieilli. Concernant l’interphase, l’analyse des échantillons bitumineux a montré qu’une diminution de l’écart de températures entre les liants conduit à un meilleur mélange. Des méthodologies ont été développées pour suivre la migration du liant vieilli au moyen de techniques comme la micro fluorescence X, la microscopie infrarouge en mode ATR et en mode d’imagerie ATR. La microscopie infrarouge en mode d’imagerie ATR est particulièrement adaptée pour étudier la remobilisation du bitume vieilli à l’aide de la fonction carbonyle qui résulte de l’oxydation du bitume et traduit son état de vieillissement. Les résultats ont permis de déterminer les paramètres influents tels que la viscosité et la nature du liant vieilli ainsi que l’effet bénéfique d’un produit « régénérant » sur la remobilisation. L’effet d’une énergie d’agitation mécanique améliore également le mélange des liants. Concernant les résultats obtenus par micro fluorescence X, des éléments métalliques entrant dans la composition du bitume ont été choisis comme traceurs internes pour suivre la migration d’un liant. Des hypothèses ont été proposées pour expliquer les différences de migration des traceurs observées. Enfin, l’ensemble des méthodologies développées à l’échelle des liants a été appliqué à l’étude des produits routiers incorporant des granulats neufs et vieillis. Les résultats montrent une cohérence entre les tendances observées à l’échelle microscopique et macroscopique. Le procédé de fabrication à chaud favorise la remobilisation tandis que l’augmentation du taux d’agrégats d’enrobé le freine. L’augmentation du taux d’agrégats réduit également l’homogénéité du mélange bitumineux fabriqué qui a été évaluée au travers de la répartition spatiale de la fonction carbonyle, obtenue par un traitement statistique des cartographies chimiques par microscopie infrarouge
In the road industry, the main challenge is to produce warm-mix asphalt mixtures while incorporating high rates of reclaimed asphalt, which come from the deconstruction of old pavement. However, the combination of recycling and the reduction of mix manufacture temperatures (warm mixes) raises technical issues about performance and durability of final pavement materials. In order to better predict final properties of these recycled materials, it is also necessary to understand phenomena occurring during the manufacture of recycled asphalt mixtures in the plant. The objectives of the PhD thesis are to understand and identify factors impacting wetting, remobilization and miscibility phenomena existing between organic and inorganic constituents of the bituminous mixture happening during the manufacturing step. The selected experimental approach consists in studying materials interactions according to a physicochemical approach at interfaces and interphases.Concerning wetting mechanisms at the “bitumen/aggregate” interface, some indicators were selected to assess wetting evolutions on a polished mineral slide. The binder ageing influence has also been studied. The bitumen viscosity and asphaltene content influence the wetting quality as well as the surface composition of the mineral substrate. Results have shown that “bitumen/aggregate” wetting evolutions were governed by a model associated to polished, porous and chemically heterogeneous surfaces.Remobilization of the aged binder (at a lower temperature) by the virgin one (heated at 160°C) has been studied at the interface and at the interphase of “aged binder/virgin binder “samples. At the bituminous interface, the spreading time is linearly influenced by the aged binder viscosity. At the bituminous interphase, bituminous sample analysis has shown that a reduction in the binders temperature difference leads to a better blend. Methodologies have been developed to monitor the aged binder migration using techniques such as X-ray micro fluorescence, infrared microscopy in ATR mode and in imaging ATR mode. Infrared microscopy in imaging ATR mode is a suitable technique to monitor the aged binder migration coupled to the carbonyl function marker resulting from the bitumen oxidation and ageing. Results have identified influent parameters corresponding to the aged binder viscosity and chemical composition, as well as the beneficial effect of a rejuvenator on remobilization. The effect of mechanical agitation energy also improves the binders blend. Concerning X-ray micro fluorescence results, binders remobilization has been assessed by the migration of metals which are involved in the bitumen internal composition. Some hypotheses have been proposed to explain observed migration differences of studied markers.Finally, all customized binder-scale methodologies have been applied to the study of road products incorporating virgin aggregates and reclaimed asphalt pavement. Results have shown similarities between observed trends at the microscopic and macroscopic scales. The hot manufacturing process promotes remobilization while the increase in the reclaimed asphalt rate limits it. The increase in the reclaimed asphalt rate also reduces the asphalt mixture homogeneity degree which has been evaluated through the carbonyl function spatial distribution, obtained by a chemical mappings statistical treatment

The thermal conductivities of foamed polymer based materials are much lower thermal conductivity values than unfoamed polymeric materials. Especially, thermal conductivity values of foamed polymers with closed-cell structure decreases to 0.03 W/m.K. The reinforcement of foamed polymeric materials by mixing with bitumen lowers the raw material cost. The main objective of this study is to make a new thermal insulation material with low thermal conductance. In this study, the effects of concentration of calcium carbonate as inorganic filler and the effects of cross-linking on the properties foamed and unfoamed ethylene-vinyl acetate (EVA) copolymer based bituminous blends and composites were investigated. Applications such as thermal, mechanical characteristics of foamed and unfoamed EVA based bituminous composites were investigated. Foamed EVA based bituminous composites were prepared by using Brabender Plastic Coder, PLV 151. Mixing was made at 120 º
C at 60 rpm for 15 minutes. The prepared blends were molded by a technique called Hand Lay-up Self-expanding Batch Molding (HLUSEBM) which was firstly applied by our group. The molding temperature was 170 º
C at which chemical blowing agent and cross-linking agent decomposes. According to test results, at moderate chemical blowing agent and EVA content, the best closed-cell structure with high porosity and low thermal conductivity values were obtained. The compressive properties of foamed polymer based bituminous composites (FPBBCs) increase with increasing CBA and EVA content. With increasing calcium carbonate and EVA concentration, the porosity of FPBBCs increases but thermal conductivity of them decreases. On the other hand, with increasing filler content but with decreasing EVA concentration elastic modulus of FPBBCs increases but elastic recovery decreases.

Although foamed bitumen has been widely applied in pavement construction some of its aspects are still not yet understood. In this study, some of these aspects including: effects of the foaming process on binder chemistry, characterization of foamed bitumen and development of a rational method to optimize foam characteristics, evaluation of aggregate particle coating within foamed bitumen treated materials, and development of a gyratory compaction procedure for laterite gravels treated with foamed bitumen were addressed. The effects of the foaming process on bitumen chemistry were investigated using Fourier transform infrared spectroscopy techniques. Also, foam characteristics of three binders were established and a rational method to optimize foam characteristics proposed. Aggregate particle coating with foamed bitumen was studied using the concepts of surface energy and Rice density. In addition a gyratory laboratory compaction procedure for laterite gravels treated with foamed bitumen was established using the modified locking concept. Infrared techniques have shown that foaming does not cause any changes in the binder chemistry, suggesting that foaming may be a physical process. Further, foam characteristics are greatly influenced by binder viscosity. Also, the equiviscous temperature seems to produce foam with optimum foam characteristics. Rice density results showed that aggregate size fraction, binder expansion ratio and viscosity influenced aggregate particle coating. Surface energy results revealed that foamed bitumen exhibited better coating attributes than neat bitumen. A new compaction procedure for laterite gravels treated with foamed bitumen based on the modified locking point was developed.
QC 20110427

Moisture damage of the asphalt mixture is defined as the loss of strength, stiffness and durability due to the presence of moisture (in a liquid or vapour state) leading to adhesive failure at the aggregate-bitumen interface and/or the cohesive failure within the bitumen or bitumen-filler mastic. The presence of moisture can accelerate the distress of asphalt pavement in several different modes, such as rutting, fatigue cracking, thermal cracking and the formation of potholes. In the field, the moisture damage normally happens first at the interface of two pavement layers or at the bottom of pavement layers and develops gradually upward. Once moisture has come into contact and interacted with the asphalt mixture, moisture damage could be developed by the following mechanisms: detachment, displacement, spontaneous emulsification, pore pressure, and hydraulic scour. It should be mentioned that moisture damage is not limited to only one mechanism but is the result of a combination of several mechanisms. As mentioned previously, the common modes of moisture damage of asphalt mixtures are a loss of adhesion between the aggregate and bitumen and/or a loss of cohesion in the mixture. Among these two failures, the adhesive failure is recognised as the main mode of moisture damage. Hence, the physico-chemical interactions between aggregates and bitumen in the presence of moisture are believed to partially govern the moisture sensitivity of asphalt mixtures, which can also affect the serviceability, performance and durability of the asphalt pavement. This thesis describes the work that was carried out with regard to the moisture damage evaluation of aggregate-bitumen bonds through different procedures. The fundamental properties of the individual material such as the chemical composition and rheological properties of bitumen, moisture absorption, surface morphology and mineralogical composition of aggregates were first characterised. Two types of equipment, namely the dynamic contact angle (DCA) analyser and dynamic vapour sorption (DVS) system were used for determining the surface energy of the bitumen and aggregates, respectively. The obtained surface energy results were then combined thermodynamically to determine the work of adhesion between aggregate and bitumen, and the reduction in the adhesive properties if water is introduced into the system. Three established mechanical tests consisting of the standard peel test, Pneumatic Adhesion Tensile Testing Instrument (PATTI) test and a pull off test were developed and redesigned to make sure that these tests are practical, reliable and feasible to measure the bonding strength of aggregate-bitumen combined specimens. The composite substrate peel test (CSPT) was developed to prepare composite substrates using crushed coarse aggregates as a more practical replacement for the aggregate substrates prepared from aggregate boulders. Finally, the moisture damage results from mechanical tests and thermodynamic results were compared and correlated with the basic physico-chemical properties of the original materials. The results showed that in the dry condition, all techniques used in this research, including the mechanical tests and the surface energy tests led to similar results, with bitumen rather than aggregates dominating the bonding properties of aggregate-bitumen systems. After moisture conditioning, the four mechanical tests, including standard peel test, CSPT, PATTI test and pull-off test showed similar moisture sensitivity ranking and failure surface results demonstrating the good correlation between these four tests. In addition, based on the comparison conducted, the four mechanical tests are all considered to be reliable to evaluate the moisture sensitivity of different aggregate-bitumen systems. However, based on the aggregates considered in this research, the moisture sensitivity parameters obtained from the surface energy tests are suggested unreliable to evaluate the moisture sensitivity of aggregate-bitumen systems.

Baigiamojo magistro darbo tikslas – ištirti Lietuvos automobilių keliams naudojamų bitumų savybes ir bitumo kiekio įtaką asfalto kokybės rodikliams. Naudojantis eksperimentinių dangų konstrukcijų bandomojo ruožo tyrimų duomenimis, atlikta viršutiniojo asfalto sluoksnio kokybės rodiklių analizė. Atlikus šių duomenų analizę, nustatytas bitumo kiekio ir mišinio fizikinių – mechaninių rodiklių tarpusavio koreliacinis ryšys. Pagal VĮ „Problematikos“ laboratorijoje atliktus bitumų tyrimų duomenis, nustatyta bitumo savybių rodiklių sietis. Tyrimų medžiaga apdorota statistiniu paketu „Statistica“. Pateiktos sunormintos bitumo kiekio ir fizikinių – mechaninių rodiklių vertės, atliktas bitumų kokybės rodiklių vertinimas. Pateiktos išvados ir rekomendacijos.
The main aim of this Master work is to analyse quality parameters of asphalt pavement and quality indicators of bitumen use for Lithuanian Roads. Using the results of the research on experimental pavement structures the quality parameters of the top layer of asphalt was analyzed. The analysis of the data allowed the correlation between the bitumen content and asphalt mixture physical and mechanical indices to be determined. Using the results of the research on „Problematika“ laboratory allowed the correlation between bitumen properties parameters. The research material was processed by means of the statistical software package „Statistica“. Standartized bitumen content and asphalt mixture physical and mechanical indices, bitumen quality indicators were valued. The conclusions and recommendations are provided.

Three bitumen-hosted ore deposits from Peru, Argentina and Chile are described. These deposits (now abandoned) contain diverse mineral assemblages and were mined for vanadium (Minasragra, Peru), uranium (Cerro Huemul, Argentina) and copper (Copiapó, Chile). Highly integrated geological and geochemical studies have enabled the construction of paragenetic sequences and genetic models for these deposits. The Minasragra deposit was a bitumen-hosted vanadium orebody located within the Central Peruvian Andes. It was characterised by a highly unusual and world-unique mineral assemblage which included the vanadium sulphide mineral, patronite. Paragenesis is divided into four distinct phases and deposit genesis is linked to the extreme alteration of an in situ vanadium and sulphur-rich bitumen vein catalyzed by the intrusion of a high-level dyke suite. Cerro Huemul is a bitumen-hosted sandstone-type U-Cu deposit located within continental facies in the Neuquén Basin. Petrographic studies of bitumens and ore species coupled with fluid inclusion analysis enable reconstruction of fluid flow through this sandstone unit. Mineralization is divided into three paragenetic stages and is integrated into a regional and deposit-specific genetic model for ore deposition. The Copiapó study focuses on an extensive andesite lava horizon of Lower Cretaceous age which contains a diverse suite of copper sulphide minerals in intimate association with solid bitumen. Petrographic studies of ore and bitumen species enable the construction of paragenetic sequence which is divided into three mineralizing stages. All three bitumen-ore deposits formed due to the presence of solid bitumen and each case study investigates the role that bitumen played in the mineralizing process. Collectively these studies provide detailed insight into mineralization processes at bitumen-hosted ore deposits and highlight the versatility of bitumens to economically-concentrate a wide range of metals and minerals. A synopsis of the formation of all bitumen-type deposits (solid bitumen veins and bitumen-hosted ore bodies) is presented and ideas regarding the potential of mineral exploration for organo-metallic deposits within the Andean Cordillera are outlined.

Thesis (MEng)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Flexible pavement designers have a choice of two wearing course: either asphalt concrete or surfacing seals. The latter have been widely used by several countries as their preferred wearing course over other methods, especially countries with a limited number of average inhabitants per square kilometre. Moreover, the surfacing seals were identified as an efficient cost effective road preventive maintenance technique. Surfacing seals in New Zealand, South Africa and Australia cover about 65%, 80% and 90% of their surfaced road networks respectively. The preference of surfacing seals is due to their competitive initial cost and ease of construction. In South Africa, the life expectancy of surfacing seals varies between 8 and 12 years with an average of 10 years. This has not been the case in a number of surfacing seals constructed in winter, especially when the night recorded temperature is below 10oC. The dominant failure mechanism is ravelling (chip loss) soon after construction due to traffic loading. This chip loss is linked to the poor adhesion bond development rate in the bitumen-aggregate system during winter adverse conditions. In order to address the issue of premature chip loss the need for the development of a robust adhesion test method was identified. For that purpose, recently, researchers in the bitumen industry developed the Bitumen Bond Strength test method. This method was used in this study. This study intends to contribute to the understanding of binder-aggregate adhesion bond development for winter surfacing seals using the BBS test. Binder type, precoat type and conditioning, aggregate type and curing time are amongst the factors influencing winter seals adhesion bond performance. An experimental matrix involving three types of binder, two types of aggregate, four different precoating fluids, two precoat conditionings and two binder-curing times were then developed and investigated. Winter weather parameters affecting adhesion properties were also taken into consideration during the course of the investigation. Throughout the test, the procedure described in AASHTO TP 91-11 was followed. However, in order to enhance the control of the binder application temperature, a new method for hot applied binder sample preparation was developed as part of this study. The findings show that there is a significant difference between adhesion properties of the hot applied binders (70/100 and S-E1) and the emulsion (SC-E1). In most of the cases, the hot applied binders performed better than the emulsion. The failure mode observed was found to be linked to the condition of the precoating. The influence of the precoat type and conditioning, and effect of binder curing time were significantly highlighted. The use of a dry precoat benefited the adhesion bond strength up to around 50% relatively to the corresponding non-precoated combination. However, a decrement in the bond strength due to precoating of up to 28.7% was also observed. A statistical analysis using ANOVA did not illustrate any statistical significant effect of the aggregate type. The interaction effects analysis using ANOVA revealed the aggregate type interacting with precoat type to be the most influential interaction at level two. The precoat conditioning implication to the adhesion development rate, which influences the time for opening to traffic after construction, was illustrated. Insightful aspects on the compatibility between the binder type and precoat type and conditioning during the aggregate precoating practices and on the time for opening to traffic are highlighted. Finally, the repeatability analysis proved the BBS test to be a repeatable testing method with caution. Recommendations for further studies that could support the conclusions drawn in this study were provided.
AFRIKAANSE OPSOMMING: Buigbare plaveiselontwerpers het 'n keuse van twee deklae: óf Asfalt of oppervlak seëls. Laasgenoemde word algemeen gebruik deur verskeie lande as hul voorkeur deklaag, veral die lande met beperkte aantal gemiddelde inwoners per vierkante kilometer. Verder, is die seëls geïdentifiseer as 'n doeltreffende koste-effektiewe deklaag tegniek. Oppervlakseëls in Nieu-Seeland, Suid-Afrika en Australië dek ongeveer 65%, 80% en 90% van hul padnetwerke onderskeidelik. Die seëls se voorkeur is te danke aan hul mededingende aanvanklike koste en eenvoudige vorm van die konstruksie. In Suid-Afrika wissel die seël se lewensverwagting tussen 8 en 12 jaar met 'n gemiddeld van 10 jaar. Dit is egter nie die geval van 'n aantal seëls wat in die winter gebou word nie, veral wanneer die aangetekende nagtemperatuur onder 10o C daal nie. Die dominante swigtingsmeganisme is stroping (klipverlies) kort na konstruksie. Hierdie klipverlies is gekoppel aan die power kleef-ontwikkeling van bitumen gedurende die winter. Ten einde die probleem van voortydige klipverlies aan te spreek het die behoefte vir die ontwikkeling van 'n robuuste toetsmetode ontstaan. Om hierdie rede het navorsers onlangs in die bitumenbedryf die “BBS toetsmetode” ontwikkel en is dié toetsmetode in hierdie studie gebruik. Hierdie studie beoog om by te dra tot die begrip van bindmiddel-klip kleefontwikkeling vir die winter seëls dmv die BBS toets. Die faktore, insluitend maar nie beperk tot bindmiddeltipe, voorafdekking (“PRECOAT”) -tipe en kondisionering, aggregaattipe en kuurtyd beïnvloed winter seëls se kleefeienskappe. 'n Eksperimentele matriks met drie tipes bindmiddels, twee tipes aggregate, vier verskillende voorafdekking-vloeistowwe, twee voorafdekking kondisionering en twee bindmiddel kuurtye is toe ontwikkel en ondersoek. Winter weer parameters wat kleefeienskappe beïnvloed is ook in ag geneem tydens die verloop van die ondersoek. Regdeur die studie is die prosedure AASHTO TP 91-11 gevolg, maar ten einde die beheer van die bindmiddel spuittemperatuur te verbeter, is ‘n nuwe metode vir warmspuit-bindmonsters voorbereiding ontwikkel as deel van hierdie studie. Die bevindinge toon dat daar 'n beduidende verskil tussen die kleefeienskappe van die warm aangewende bindmiddels (70/100 en S-E1) en die emulsie (SC-E1) is. In die meeste van die gevalle het die warmspuit-bindmiddels beter as emulsie gevaar. Daar is gevind dat die swigtingsmeganisme verbind word met die toestand van die voorafdekking. Die invloed van voorafdekkingtipe, kondisionering, en die effek van bindmiddelkuurtyd is duidelik uitgelig. Die gebruik van droë voorafdekking het die kleefkrag tot sowat 50% verhoog relatief tot die ooreenstemmende onbedekte klipkombinasie. Daar is egter ook ‘n verlaging van die kleefkrag weens voorafdekking gevind van tot so hoog soos 28,7 persent. Die statistiese ontleding met behulp van ANOVA het geen statisties beduidende effek van die verksillende aggregaattipe te vore gebring nie. Die interaksie-effek analise, met behulp van ANOVA, het wel die interaksie met voorafdekkingtipe met aggregaat die mees invloedryke bevestig. Die voorafdekking kondisioneering het ver rykende kleefkrag implikasies bloot gelê, wat die tyd vir die opening van die verkeer na konstruksie beïnvloed. Insigwekkende aspekte oor die versoenbaarheid tussen die bindmiddeltipe, voorafdekkingtipe, kondisionering, voorafdekkingpraktyk en tyd tot opening vir verkeer word uitgelig. Ten slotte, die herhaalbaarheidsanalise het die BBS toets as 'n herhaalbare toetsmetode met omsigtigheid bewys. Daar is aanbevelings tot verdere studies, wat uit die gevolgtrekking gekom het, gemaak.

La ricerca riguarda lo studio delle modifiche indotte dalla diffusione di acqua e umidità nelle pavimentazioni stradali con riferimento ai materiali bituminosi. Lo scopo è stato quello di analizzare le implicazioni che si sviluppano a livello chimico e reologico in vari bitumi. In questo progetto oltre alla fase sperimentale, è stato utilizzato un software per la simulazione agli elementi finiti. Per quanto concerne la fase di laboratorio, è stato sviluppato un nuovo protocollo di condizionamento. Tre diversi bitumi sono stati soggetti alla diffusione di acqua in forma liquida o vapore, a determinate condizioni ambientali e per svariati intervalli temporali. Grazie a l’utilizzo di due camere climatiche il condizionamento è stato realizzato in modo uniforme a precisi valori temperatura e umidità mantenuti stabili. I materiali analizzati: un bitume soft, uno hard, ed infine uno modificato con l’aggiunta di polimeri. Il dispositivo FTIR-ATR è stato utilizzato per la caratterizzazione chimica, mentre il comportamento reologico è stato analizzato tramite test eseguiti con il DSR. Le avanzate tecnologie presenti nel laboratorio della TU Delft hanno consentito di ottenere notevoli risultati. L’analisi è stata condotta con l’obiettivo di evidenziare i diversi cambiamenti indotti dalla diffusione di acqua liquida o vapore e per analizzare l’influenza della temperatura, del tipo del bitume e dell’incremento del tempo di condizionamento. Una analisi analoga è stata condotta parallelamente, con lo scopo di investigare la correlazione tra il processo di invecchiamento e la diffusione di umidità. Infine, la simulazione agli elementi finiti è stata sviluppata tramite il software CAPA-3D per analizzare il comportamento del bitume in periodi più estesi di diffusione di umidità. Inoltre, il comportamento dei bitumi è stato studiato anche in presenza di particelle di riempitivo. Particelle granitiche e calcaree sono state aggiunte ai bitumi in differenti percentuali.

The main goal of this dissertation is to develop simple and accurate models for thetransient monotonic and cyclic deformation behaviour of bitumen and asphalt mixes. The first part of this dissertation is concerned with an experimental and theoreticalinvestigation of the deformation behaviour of bitumen. The second part is concernedwith the deformation of bituminous mixes. A brief description of the main literature on composition, structure and mechanicalbehaviour of pure and polymer-modified bitumens is presented in chapter 2.An extensive experimental study comprising of monotonic, continuous cyclic andpulse loading tensile experiments for two pure and two polymer-modified bitumensis detailed in chapter 3. Based on these experimental findings a simple constitutivephenomenological model including the effects of rate dependent recovery is proposedfor bitumen. Comparisons between experiments and model predictions are presentedwith good agreement. The spherical indentation behaviour of bitumen under monotonic and cyclic loadingconditions is studied in chapter 4. A simple extension to the power-law indentationmodel of Bower et al. (1993) is proposed for bitumen with good agreement withexperimental results. Chapter 5 presents a review of the main research on continuum and micro-mechanicalmodels for the deformation behaviour of bituminous mixes. An extensive experimental investigation of the monotonic and cyclic compressivedeformation behaviour of bituminous mixes with varying volume fractions of aggregate,for uniaxial and triaxial conditions, is described in chapters 6 and 7, respectively. An extension to the phenomenological model proposed for bitumen is proposed forthese mixes. The predictions of the model are compared with the experimental resultswith good agreement. In chapter 8, a micro-mechanical constitutive model for the deformation behaviourof asphalt is assembled using micro-mechanical theories and experimental observations. The model predictions are compared with uniaxial and triaxial experimentalresults, showing reasonably good agreement. Finally, conclusions and recommendations for future work are presented in chapter 9.

The thesis examines challenges and opportunities for the Canadian oil sands industry in the three most important markets: the USA, currently the sole export destination, and the European Union and China, the two largest potential consumers of highly carbon-intensive Canadian bitumen. Gradually falling demand for oil imports and increasing carbon consciousness in the American market threaten to impose constraints on the further development of Alberta`s oil sands and prompt the industry to look for alternative export destinations. Energy security concerns in the European Union amid the crisis in Ukraine, and in China due to political instability in the Middle East trump environmental policies of the two jurisdictions and present an opportunity for the Canadian bitumen industry to tap into these markets. However, the current infrastructure constraints stemming from formidable public opposition to the construction of new oil pipelines render Canada unable to capitalize on this opportunity. The long-term future of Alberta`s oil sands is therefore far from certain.
Arts, Faculty of
Political Science, Department of
Graduate

The rheology of oil sand slurries was investigated under different physicochemical conditions in an attempt to establish a correlation between bitumen liberation and slurry rheology. Synthetic mixtures of bitumen with fine quartz of varying bitumen content, as well as actual oil sand ores, were used in all the tests. All rheological measurements were conducted using a rotational viscometer connected to a fixture specifically designed for testing settling suspensions. The results showed that for both synthetic mixtures and actual oil sand ores the viscosity of the slurries decreases with increasing bitumen liberation. It was found that at low bitumen contents (0 and 1 wt%) the pH of the slurries was the most important parameter that controlled the rheology of synthetic quartz-bitumen slurries. At higher bitumen contents (5 and 10 wt%), it was a combination of high temperature and high pH that gave the lowest viscosities and yield stresses of the model mixtures. The overall results were discussed in terms of aggregation-dispersion phenomena between bitumen and mineral particles. The effect of salts such as NaCl, CaCl₂ and KCl on the rheology of synthetic mixtures was found to be small compared to the effects of pH and temperature. Experiments performed on slurries where bitumen was added as an emulsion (no attachment to solids) showed that viscosity was significantly lower compared to a suspension in which bitumen coated the solid particles. Humic acids were tested also in slurries of synthetic bitumen-quartz mixtures at 10 wt% bitumen showing that they produce an important improvement in rheology when they are added at dosages of 100 g/t or higher. These observations on synthetic ores could qualitatively be used to predict the rheology data for slurries of four actual oil sand ores. In this case, it was also found that the content of very fine particles (% fraction finer than 3 microns) was the most significant variable that clearly correlated with the viscosity of the oil sand ore slurries.

Biomass waste has been recognised as a promising, renewable source for future transport fuels. With 1.7 million hectares of pine plantation forests and 12 million cubic meters of annual residue produced by sawmills and the pulp and paper industries, New Zealand presents a prime location where utilisation of these resources can take the next step towards creating a more environmentally friendly future. In this research, the process of fast pyrolysis was investigated using a laboratoryscale, nitrogen-blown fluidised bed pyrolyser at CRL Energy. This equipment can process 1–1.5 kg/h of woody biomass in a temperature range of 450–550°C. The purpose of this rig was to determine the impact of various processing parameters on bio-oil yields. Next, the pyrolysis liquids (bio-oil and tar) were processed downstream into bio-bitumen. Pyrolysis experiments were carried out on Pinus Radiata and Eucalyptus Nitens residue sawdust from sawmills and bark feedstock. The properties of the collected products, including pyrolysis liquids (bio-oil and tar), gas and solid bio-chars, were measured under different operational conditions. Further analysis was also performed to determine pH, volatile content, chemical composition and calorific values of the products. The ultimate goal for this project was to develop a feasible, advanced fast-pyrolysis system for a bio-bitumen production plant using various biomass feedstocks. Additionally, a design for a bio-bitumen production plant was developed, and techno-economic analysis was conducted on a number of plant production yield cases and bio-bitumen manufacture ratios.

in heated penetration and oxidised grade bitumen storage tanks in the USA, a number of suggestions were made concerning the possible presence of components of the fire triangle. If such conditions exist, then the need for inerting tanks held above certain storage temperatures can be demonstrated. Current practice relating to the handling and storage of bitumens in the UK has been examined, and measurements made at refineries, Quarries and other installations storing bitumen under elevated temperatures. This has been supplemented by the building of small scale replicas in the laboratory so that conditions in full scale tanks could be simulated. This enabled generation of flammability and gas concentration data for a variety of bitumens. A thorough investigation of bitumens and their associated coke-like deposits has been made. Flash and autoignition points have been determined, While a range of thermal analysis techniques have been employed to determine the pqssible existence of exothermic decomposition reactions. Inter alia gas Chromatography/mass spectrometry and infrared analysis techniques has enabled a detailed study to be made of the decomposition products evolved from bitumens and deposits on heating. Scanning electron microscopy and the use of a micro-combustion technique has provided information on the elemental composition. The physical properties of penetration value, -softening point, viscosity and thermal conductivity have also been determined for bitumens. It has been found that current UK practice may, in some cases, permit two sides of the fire triangle to exist in non-inerted tanks. The presence of a third component, an ignition source has not yet been substantiated. Flammable atmospheres can exist in storage tanks at the currently . recommended maximum storage temperatures. This is particularly the case with the oxidised grade bitumens which eXhibit high values of %LEL at these temperatures.

Bitumen emulsion mixtures, or cold mix, offers certain advantages over hot bituminous road mixtures in terms of potential cost savings, environmental factors, energy savings and easing of logistical difficulties inherent with hot mix. For these reasons, they are currently used in a number of regions including the United States of America, Continental Europe, Scandinavia, Southern Africa and Australia. However, cold mix has not been seriously evaluated or utilized in the UK until comparatively recently. This is due to the slow rate at which it builds strength or cures and its susceptibility to rainfall, particularly during this curing period. The overall aim of this research was, therefore, to study the behaviour of cold mix in terms of mechanical properties and the mechanisms involved in emulsion breaking and mixture curing to gain an insight into how performance may be improved. Mechanical properties were shown to be affected by a number of parameters, including binder grade, void content, curing time and additives such as cement. Fatigue tests showed that without cement, the performance in-situ of cold mix would be very poor. Pavement design calculations revealed that, with cement, emulsion mixtures could be expected to perform similarly to equivalent hot mix. Field trials have indicated that cold mix can be manufactured using conventional hot mix plant and laid using similar techniques. However, problems are still to be overcome in terms of the control of mixture composition and laying in adverse weather conditions. Fundamental tests have shown that emulsion droplet coalescence (which is an essential part of the curing process) was affected by pressure, bitumen type, emulsifier level, cement and temperature and that cement can cause emulsion charges to become more positive (or less negative) but other parameters had no effect on charge. It was also proved that cement can cause bitumen emulsion to set completely and that the residual binder has an increased viscosity compared with unmodified binder. This was shown to be due to the formation of a composite bitumen cement binder.

Au cours de cette thèse, de nouvelles méthodes d’analyse thermique et de traitement des données applicables à l’étude et la caractérisation de produits pétroliers complexes, ont été proposées, afin de mieux caractériser les bitumes. Le bitume, sous-produit de l’industrie pétrolière, est un matériau complexe dont les propriétés et la composition changent au gré des cocktails de pétroles bruts ou des procédés de raffinage. Une connaissance approfondie des propriétés de chaque bitume est donc nécessaire. Les tests mécaniques normés utilisés aujourd’hui pour caractériser le bitume sont insuffisants. Afin de pallier ce problème les techniques de DSC avancées ont été exploitées. Ce travail a porté principalement sur l’étude des trois phénomènes pouvant être observés au cours du chauffage des bitumes: la transition vitreuse, la cristallisation et la fusion. La première partie de ce travail a été consacrée à l’étude de ces trois phénomènes sur des molécules modèles, la diéthanolamine et la triéthanolamine. L’intérêt de la perturbation stochastique de température (TOPEM®) réside notamment dans la possibilité de séparer certains phénomènes se produisant sur un même domaine de températures. La méthodologie développée a ensuite été appliquée aux bitumes afin de mettre en évidence des corrélations entre données DSC (fraction cristallisable, température de transition vitreuse, température et enthalpie de fusion) et données mécaniques. Il a été montré également que la calorimétrie ultra-rapide permet de séparer certains phénomènes grâce à une approche différente mais complémentaire à la perturbation stochastique de température TOPEM®
This thesis tackled new methods of thermal analysis and data treatment applicable to the study and characterization of complex petroleum products. The objective was to better characterize bitumen, which, as a by-product of petroleum industry, is a complex material. Its properties and composition are not set and change according to the cocktails of crude oils or to the refining processes. Thorough knowledge of the properties of asphalt is thus necessary to be able to use them in the best conditions. The standardized mechanical tests used today to characterize the asphalt are insufficient. To compensate for this problem, the techniques of advanced DSC were exploited. This work concerned mainly the study of three phenomena which can be observed during the heating of asphalts: glass transition, crystallization, and melting. The first part of this work was dedicated to the study of these three phenomena on model molecules _ the diethanolamine and the triethanolamine _ as they were presenting thermal events in a range of temperatures similar to the one of bitumen. The interest of the stochastic temperature perturbation (TOPEM®) lies in particular in the possibility of separating some phenomena occurring on the same range of temperatures. Thus, thanks to this method, glass transition can be analyzed independently of the enthalpic relaxation or of the crystallization. The developed methodology was then applied to bitumen so as to highlight correlations between DSC data and mechanical data . It was also shown that the ultra-fast calorimetry enables to separate some phenomena thanks to a different but complementary approach of stochastic temperature perturbation TOPEM®

Instrumented indentation testing was used to determine viscoelastic properties of bitumen, i.e. shear relaxation modulus. Review of previous studied reveals that indentation testing technique has been drawing increasing attempts in investigations of binder material mechanical properties. Various properties of bitumen, e.g. elastic, viscoelastic, have been successfully determined by indentation testing at different scales and test conditions. The response of bitumen to indentation was studied extensively under a wide range of test parameters such as temperature, loading rate, indenter geometry, etc. This experimental tool was also applied to asphalt cements grading and microstructure study. However, there have been limited numbers of studies at macro levels with the use of spherical indenters to characterize bitumen properties. This motivated the present study. Spherical indentations have been performed with balls of different curvature radii at -5 oC. Load – displacement curves have been measured and used to determine the relaxation moduli of the studied bitumen. Repeatability of the measurements has been evaluated. Obtained results were compared with the observations from DSR relaxation test. The influence of the measurement scale and load level on the results of instrumented indentation testing has been investigated. It has been found that instrumented indentation was able to characterize accurately the viscoelastic behavior of bitumen which can be described by Prony series and agrees well with the results from DSR tests. Nevertheless, the elastic solution failed to produce a proper description of bitumen response during loading phase.

The project was informed by non-rational modes of perception which explored the matrix of dream, imagination, my body and the viewer. The material from this matrix was brought together and translated into artworks through the use of every day materials, techniques and procedures. The resulting artwork offered an experience in the form of an installation which included projected images, aural landscapes, tactile surfaces and spatial constructions.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The research conducted in this study forms part of the Phase II process of the Bitumen Stabilized Materials (BSMs) Guideline improvement initiative. The initiative aims to address areas of concern in the cold mix design procedures for BSMs. Current road rehabilitation using the bitumen stabilization process requires testing of representative specimens as means to evaluate pavement performance over time. In order to adequately acquire specimens representative of field conditions, it is necessary to condition the materials in a process called curing. Although curing procedures have been standard in many countries on different continents, the protocols are varied and an acceptable procedure is currently not available. In order to develop an acceptable curing protocol for BSMs, both field and laboratory environments were investigated. Considering that curing takes time in the field, production of representative samples intended for laboratory testing must undergo accelerated curing in the laboratory. Given the complexities involved in achieving close correlations between field and laboratory environments, the research strived to reconcile field and laboratory material behaviour. In particular, the main objective of the research was to unify the curing protocol for BSMs, with the standardization of the curing protocol being top priority. In this study, laboratory results have confirmed that the different natures of curing mechanisms inherent in a BSM-foam and BSM-emulsion contribute to irreconcilable material behaviour(s). Results have confirmed that curing of BSM-foam is largely a function of water repulsion, with the addition of active filler dominating material performance almost immediately. Unlike BSM-foam, curing of BSM-emulsion is both a function of the breaking of emulsion during the initial phase and the gradual release of moisture with time. In this instance, BSM-emulsion material performance resembled active filler influences past the breaking of the emulsion cycle. Consequently, given the observed differences regarding material behaviour(s), the unification of the curing protocol for BSMs has not been successful. In terms of accommodation of active filler in the final curing protocol for BSMs, findings in this research have revealed that active filler’s tendency to absorb moisture in the initial stages requires longer curing time to help extract the absorbed moisture during the curing process. Although the use of active filler has an impact on curing, its inclusion in a BSM does not justify its extension in the curing time as cementation is not one of the desired properties of these materials. BSMs are primarily desirable for their flexibility in pavement structures. For this reason, active filler was omitted in the final curing protocol due to reasons of simplifying the mix design process. In conclusion, different curing protocols were tested and developed to help produce reconcilable material behaviour in both the field and laboratory environments. Through the reconciliation of key material properties such as the resilient modulus, long term equilibrium moisture conditions and shear parameters, an acceptable standardized curing protocol for BSM-foam and BSMemulsion intended for application in industrial laboratories across South Africa was successfully developed.
AFRIKAANSE OPSOMMING: Die navorsing tydens hierdie studie gedoen, vorm deel van die Tweede fase van die Bitumen Gestabiliseerde Materiale Riglyne verbeteringsinisiatief. Die inisiatief het ten doel om areas van bekommernis in die kouemengsel-ontwerp-prosedures vir Bitumen Gestabiliseerde Materiale aan te spreek. Huidige padrehabilitasie wat gebruik maak van die Bitumen Gestabiliseerde Materiale proses, vereis toetsing van verteenwoordigende monsters om sodoende plaveiselgedrag oor ‘n tydperk te evalueer. Materiale moet deur die verouderingsproses gekondisioneer word, om sodoende monsters te verkry wat akkuraat verteenwoordigend van veldtoestande is. Alhoewel verouderingsprosesse in meeste lande - op verskillende kontinente - gestandariseerd is, is die protokol verskillend en ‘n aanvaarbare prosedure is nie tans beskikbaar nie. Beide veld- en laboratoriumomgewings is ondersoek, om sodoende ‘n aanvaarbare verouderings-protokol vir Bitumen Gestabiliseerde Materiale te ontwikkel. Wanneer in ag geneem word dat veroudering in die veld tydrowend is, moet vervaardiging van verteenwoordigende monsters vir laboratoriumgebruik versnelde veroudering in die laboratoruim ondergaan. Gegee die kompleksiteite betrokke om goeie korrelasie tussen velden laboratoriumomgewings te verkry, het die navorsing daarna gestreef om die veld- en laboratoriummateriaalgedrag te verenig. Die hoofdoel van die navorsing was om die verouderingsprotokol vir Bitumen Gestabiliseerde Materiale te verenig met die stardaardisering van die verouderingsprotokol as top prioriteit. In hierdie studie het laboratorium resultate bevestig dat die verskillende aard van voorbereidings- meganismes inherent in BSM-skuim en BSM-emulsie bydra tot onversoenbare materiaalgedrag. Resultate het bevestig dat voorbereiding van BSM-skuim ’n funksie van waterrepulsie het en met die byvoeging van aktiewe vullers dominieer dit die materiaalgedrag byna onmiddelik. Anders as BSM-skuim is die voorbereiding van BSM-emulsie beide ’n funksie vir die breek van emulsie tydens die begin fase en die geleidelike vrystelling van vog oor tyd. In hierdie geval het BSM-emulsie se materiaalgedrag die invloed van aktiewe vuller getoon nadat die emulsie gebreek het. Gevolglik, weens die waargenome verskille rakende materiaalgedrag is die vereniging van die voorbereidings- protokols vir BSMs nie suksesvol nie. In terme van inagneming van aktiewe vullers in die finale voorbereidingsprotokol vir BSM’s, is deur navorsing bevind dat aktiewe vullers neig se neiging om vog te absorbeer in die beginstadia dit benodig dus ‘n langer verouderingstyd vir die ontrekking van die geabsorbeerde vog. Hoewel die gebruik van aktiewe vullers ’n impak het op die voorbereiding, reverdig dit nie die verlenging van die verouderingstyd vir die insluiting daarvan in BSM nie, siende dat sementering nie een van die gewenste eienskappe van hierdie materiaal is nie. BSMs word hoofsaaklik verkies vir sy buigsaamheid in paveiselsturkture. Om die mengselontwerp prosesse te vereenvoudig, was aktiewe vullers dus weggelaat in die finale voorbereidingsprotokol. Ter afsluiting was verskeie voorbereidings protokolle getoets en ontwikkel om te help met die vervaardiging van versoenbare materaalgedrag in beide veld-en-laboratoriumomgewings. Deur die versoening van kern materiaal eienskappe soos die elastisiteitsmodulus, lang termynewewigvog kondisies en skuifparameters, is ’n aanvaarbare gestandariseerde voorbereidingsprotokol vir BSM-skuim en BSM-emulsie bedoel vir aanwending in industriele laboratoriums regoor Suid Afrika suksesvol ontwikkel.

Thesis (MScEng)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: This research investigates the flexibility and the performance properties of bitumen stabilised materials under the influence of mix variables. The laboratory testing consisted of two main phases. During the first phase (mix design), the strength and the flexibility of the mixes were assessed through ITS (Indirect Tensile Strength), UCS (Unconfined Compressive Strength), displacement at break, strain at break and fracture energy. The second phase consisted of a series of triaxial tests done to assess the performance properties (shear strength: cohesion and angle of internal friction; and stiffness: resilient modulus) of the mixes. The mineral aggregates used in this study were milled from different locations of the R35, near Bethal. This was a blend of granular material (dolerite, from various locations of the existing base and subbase layer of the R35) and Reclaimed Asphalt (RA) milled from the existing surfacing. During the mix design phase, two types of bituminous binders were used (bitumen emulsion and foamed bitumen) at bitumen content ranges of 2%, 2.4% and 2.8% each. Two types of active filler were used separately and in combination at a proportion of 1% and 2%. Finally, specimens were tested in wet and dry conditions for each mix combination. During the triaxial testing phase, only the optimum bitumen content of 2.4% was used, both for bitumen emulsion and foamed bitumen, with only cement as active filler in a proportion 1% and 2%. The specimens were tested at different ranges of densities and saturation levels. The flexibility of the mix was assessed through the fracture energy, the strain and the displacement at break parameters. An analysis of variance (ANOVA) was conducted on the data to assess the significance of experimental variables on this property. This property was found to be very sensitive to bitumen and cement content added to the mix. When assessing the combined effect and the significance of the variables on the flexibility of the mixes, it was found that fracture energy is mostly influenced by the cement content, followed by the bitumen content, then the type of treatment and finally the testing condition. However, the level of significance was not in the same order for the other two parameters (displacement and strain at break). It was also found that the combined effect of some independent variables (cement content + testing condition, type of treatment + cement content + bitumen content) had a significant effect on the fracture energy and the strain at break respectively. From the ITS and UCS tests, an increase in strength was noticed with the increase of cement content. On the other hand, the increase in bitumen content led to a decrease in strength of the material. The statistical analysis on the ITS and UCS values show that the independent variable with the most significant effect on the ITS is the cement content, followed by the testing conditions, then the bitumen content and finally the type of treatment. The combined effect of cement content + bitumen content was found to be significant both for ITS and UCS. In the second phase triaxial tests were performed in order to evaluate the performance properties of the mixes. It was found that the increase of the active filler content significantly improves the shear strength of the material. It was also found that at a fixed cement content, specimens tested at low density and/or high level of saturation show low shear strength. The Mr-θ model was used to model the resilient modulus of the mixes and the model coefficients used to evaluate the effect of experimental variables on the resilient modulus. It was found that the resilient modulus of the mixes increases as the bulk stress increases. This confirms the stress dependent behaviour of bitumen stabilised materials. The analysis show that increasing the percentage of active fillers content results in a significant increase in the resilient modulus values. An increase in relative density also resulted in an increase in the resilient modulus of the mixes, while the opposite effect was observed with the increased of the saturation level. Besides the engineering properties and the mechanical test parameters, other parameters such as the Tensile Strength Ratio (TSR) was calculated in order to evaluate the moisture sensitivity of the mixes. Weakening due to moisture was found to be more predominant in the mixes with less active filler. In addition, bitumen emulsion mixes were found to have a better resistance to moisture weakening effects compared to foamed bitumen. In addition, a comparison between the rapid curing and the accelerated curing was done. Higher ITS and UCS results were obtained for specimens cured using long term curing compared to specimens cured using the accelerated curing method. In conclusion, flexibility is an important property of bitumen road construction material (bitumen stabilised material include) however, it is not an easy property to measure. Although, displacement/strain at break and fracture energy from ITS and UCS were able to give us some indications on the main factors governing the flexibility of bitumen stabilised materials (the bitumen and active filler content), more accurate and adequate tests are required to evaluate the parameter.
AFRIKAANSE OPSOMMING: Die buigsaamheid en gedragseienskappe van bitumen gestabiliseerde materiale was getoets om sodoende die invloed van verskeie mengselveranderlikes te evalueer. Die ondersoek het uit twee fases bestaan. Tydens die eerste fase (mengfase) is die sterkte en buigsaamheid deur middel van indirekte treksterkte toetse (ITS), onbegrensde druksterkte toetse (UCS), verplasing – en vervorming by breekpunt sowel as breek-energie toetse gedoen en ondersoek. Die tweede fase het bestaan uit ʼn reeks drie-assige triaksiaal toetse. Triaksiaaltoetse is uitgevoer om die gedragseienskappe soos die skuifsterkte, kohesie, hoek van interne wrywing, styfheid en weerstand modulus te ondersoek. Die gemaalde mineraal-aggregaat wat in hierdie ondersoek gebruik is, was verkry op verskeie areas van die R35, geleë naby Bethal. Die materiaal is ʼn mengsel van granulêre materiaal (van die bestaande kroonlaag en stutlaag van die pad) en herwonne asfalt (RA). Tydens die mengontwerp fase is twee tipes bitumen gebruik naamlik bitumenemulsie en skuimbitumen in hoeveelhede van 2%, 2.4% en 2.8%. Twee tipes aktiewe vulstof (hoeveelhede van onderskeidelik 1% en 2%) was saam met elk van die verskeie bitumen-hoeveelhede gebruik. Proefstukke van elk van hierdie mengsel kombinasies is onder beide nat en droë kondisies getoets. Tydens die tweede fase, is slegs die optimum binder inhoud (2.4%) gebruik vir beide emulsie- en skuimbitumen, gekombineer met 1% en 2% aktiewe vulstof. Proefstukke was getoets by ʼn reeks van verskillende digthede en versadigingvlakke. Die buigsaamheid was ondersoek deur middel van breek-energie, vervorming en die verplasing by breekpunt. ʼn Analise van variasie (ANOVA) is uitgevoer op die toetsdata om sodoende die te evalueer of die veranderlikes beduidend is ten opsigte van buigsaamheid. Daar is gevind dat die buigsaamheideienskap sensitief is vir beide bitumen en sement inhoud. Met assessering van die gekombineerde effek en betekenis van die veranderlikes op die buigsaamheid van die mengsels, is daar gevind dat die hoogste beduidende veranderlike t.o.v breek-energie die sement inhoud is, gevolg deur die bitumeninhoud, tipe behandeling en laastens die toetskondisie. Die orde van belangrikheid verskil vir die ander twee parameters (verplasing en vervorming by breekpunt). Daar is ook gevind dat die gekombineerde effek van sommige veranderlikes (sement inhoud en toets kondisie, tipe behandeling en sement inhoud tesame met bitumen inhoud) ook beduidend was t.o.v breek-energie en vervorming by breekpunt. Vanuit die ITS en UCS toetse was daar ʼn toename in sterkte waargeneem soos die sementinhoud toeneem. Aan die anderkant, het ʼn toename in bitumeninhoud ‘n afname in sterkte veroorsaak. Die statistiese analise van ITS en UCS resultate, toon dat die grootste beduidende onafhanklike t.o.v ITS waardes ook die sement inhoud was, gevolg deur toets kondisies die grootste effek, bitumen inhoud en die tipe behandeling. Die gekombineerde effek van sementinhoud en bitumeninhoud, was betekenisvol vir beide ITS en UCS. Drie-assige triaksiaaltoetse was uitgevoer om die gedragseienskappe van die mengsels te evalueer. Daar is gevind dat die toename in sement inhoud, die skuif sterkte van die materiaal grootliks verbeter. By ʼn konstante sementinhoud, wys toetsresultate van proefstukke wat getoets is by lae digthede en hoë vlakke van versadiging, lae skuif sterkte. Die Mr – θ model was gebruik om die veerkragsmodulus van die mengsels te moduleer en die modelkoëffisiënte is gebruik om die effek van eksperimentele veranderlikes op die weerstand modulus te evalueer. Met toename in die omhullende spanning is ‘n toename in die veerkragsmodulus waargeneem, wat bevestig dat die gedrag van bitumen gestabiliseerde materiale spannings afhanklik is. ʼn Toename in die sement en relatiewe digtheid het ʼn merkwaardige toename in die veerkragsmodulus tot gevolg gehad, terwyl die teenoorgestelde waargeneem is met toename in versadigingsvlakke. Buiten die ingenieurseienskap en meganiese toetsfaktore, is ander faktore (soos die trekspanning verhouding) bereken om die vogsensitiwiteit van die mengsels te evalueer. Mengsels met laer sement inhoud het groter verswakking ervaar met blootstelling aan water. Bitumenemulsie proefstukke toon beter weerstand teen water as skuimbitumen. Vergelyking tussen versnelde en korttermyn nabehandelingsprosedure van proefstukke, toon hoër ITS en UCS waardes vir die versnelde nabehandelingsprosedure prosedure. Buigsaamheid is ‘n belangrike eienskap van bitumen in padkonstruksie materiale (insluitend bitumen gestabiliseerde materiale), maar word moeilik gemeet. Alhoewel verplasing/vervorming by breekpunt en breek energie, bepaal vanaf ITS en UCS, ‘n indikasie toon van die hooffaktore (binder en sement) wat buigsaamheid van bitumen gestabiliseerde materiaal beïnvloed, word meer akkurate toetse benodig om die eienskap te ondersoek.

Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: The increasing awareness of climate change causes a growing interest in pavement rehabilitation. Pavement rehabilitation by in-situ stabilisation with bitumen reduces the extraction of natural aggregate resources while enhancing flexibility and durability properties, which lowers maintenance costs over the design-life of the pavement structure. Incorporating Bitumen Stabilised Materials (BSMs) into a pavement structure can therefore have economic and environmental benefits, but more research is needed to fully understand the behaviour and potential of these materials. Stabilising materials with bitumen provides useful properties to pavement layers. The “TG2 2nd Edition, Bitumen Stabilised Materials” was published by the Academy of South Africa in May 2009, which provides a good understanding of the usage of Bitumen Stabilised Materials (BSMs). However, the shrinkage and flexible behaviour of these materials are still not fully understood and therefore more research on these materials is needed. The aim of this project is thus to determine the shrinkage and flexible behaviour of BSMs to incorporate these behavioural types in the revised design method for flexible pavements in the SAPDM. In addition, the influence of several additives on the shrinkage and flexible behaviour of BSMs have been evaluated to get an improved understanding of these properties. The additives included cement (1% and 2% content) and both bitumen emulsion (0.9% and 2.4% content) and foamed bitumen (only 2.4% content). Two linear shrinkage testing methods have been designed to test the shrinkage potential of BSMs, including a beam testing method and a cylindrical testing method. Based on the usage of the shrinkage measurements the applicable method can be used to determine the shrinkage potential of a BSM. The flexibility is a more complex property and was tested using a simple monotonic beam test. The strain-at-break parameter obtained from this test provided an indication of the material flexibility. Slight differences in the trends were observed between beam and cylindrical shrinkage due to specimen geometry, exposed surface area and shrinkage testing direction. Beam specimens initially show swelling when bitumen is added to the mixture and shrinks thereafter. Cylindrical specimens on the other hand show initial shrinkage followed by a slight length increase, where after shrinkage continues. The additives had the same influence on the shrinkage for both the beam and cylindrical specimens. Although all shrinkage measurements were small, an increase in bitumen reduced shrinkage and an increase in cement increased shrinkage. Stabilisation with foamed bitumen rather than bitumen emulsion proved to show less shrinkage, but only in combination with 2% cement. The strain-at-break, dissipated energy and material stiffness calculated from the monotonic beam tests provided a good indication of the flexibility behaviour of BSMs. Higher bitumen content increased the flexibility potential and an increase in cement decreased the flexibility potential of BSMs. This project has provided good insight on both the shrinkage and flexibility behaviour of BSMs, which can be used in the revised copy of the SAPDM. Increased bitumen contents decreases the shrinkage potential and increases the flexibility of a BSM. Increased cement contents on the other hand, increases shrinkage and decreases flexibility of BSMs. The correct combination of cement and bitumen in a BSM can thus provide a material with the wanted flexibility while keeping the shrinkage to a minimum.
AFRIKAANSE OPSOMMING: Die toenemende bewustheid van klimaatsverandering veroorsaak toenemende belangstelling in die rehabilitasie van plaveisels. Plaveisel rehabilitasie deur in-veld stabilisasie met bitumen verminder die ontginning van natuurlike hulpbronne, terwyl die verbetering van buigsaamheid en duursaamheid eienskappe die onderhoudskoste verlaag oor die ontwerp-lewe van die plaveiselstruktuur. Die inkorporasie van Bitumen Gestabiliseerde Materiale (BGM) in 'n plaveisel struktuur kan dus omgewings en ekonomiese voordele inhou. Meer navorsing word wel benodig om die gedrag van hierdie materiale beter te verstaan. Die stabilisering van materiale met bitumen verskaf nuttige eienskappe aan 'n plaveisellaag. Die "TG2 2de Uitgawe, Bitumen Gestabiliseerde Materiale" is gepubliseer deur die Akademie van Suid-Afrika in Mei 2009 en verskaf 'n goeie begrip van Bitumen Gestabiliseerde Materiale (BGM). Die krimpings en buigsaamheid gedrag van die materiaal word wel nog nie ten volle verstaan nie en daarom word meer navorsing oor hierdie materiaal benodig. Die doel van hierdie projek is dus om die krimpings gedrag sowel as die buigsaamheid gedrag van 'n BGM te bepaal en sodoende die kennis te gebruik in die hersiende ontwerp metode vir buigsame plaveisels in die SAPDM. Die invloed van verskeie bymiddels op die krimpings en buigsaamheid gedrag van 'n BGM is ook geëvalueer om 'n beter begrip van hierdie eienskappe te verkry. Die bymiddels sluit sement in (1% en 2% inhoud) asook beide emulsie bitumen (0,9% en 2,4% inhoud) en skuim bitumen (slegs 2.4% inhoud). Twee lineêre krimpings toets metodes was ontwerp om die krimping potensiaal van BGM's te bepaal, wat 'n balk toets metode en 'n silindriese toets metode insluit. Die metode wat gebruik sal word om die krimping van 'n BGM te bepaal moet baseer word op die toepassing waarvoor die krimpings resultate gebruik gaan word. Die buigsaamheid is 'n meer komplekse eienskap en was getoets met behulp van 'n eenvoudige monotoniese balk toets. Die spanning-by-breekpunt waardes wat verkry was vanuit die balktoetse, het 'n goeie aanduiding van die buigsaamheid van die materiaal verskaf. Klein verskille in krimpingstendense tussen balk en silindriese proefstukke is opgemerk tydens die projek en is veroorsaak deur die geometrie van die proefstuk, die blotgestelde oppervlakte asook die rigting van kimp toetsing. Balk proefstukke toon aanvanklike swelling wanneer bitumen bygevoeg is, gevolg deur krimping. Silindriese proefstukke aan die ander kant toon aanvanklike krimping gevolg deur 'n effense toename in lengte, waarna krimping weer plaasvind. Die bymiddles het dieselfde invloed op die krimping van beide die balk en silindriese proefstukke. Alhoewel al die krimpingswaardes baie klein was, het 'n toename in bitumen 'n vermindering in krimping voortgebring en 'n toename in sement het 'n toename in krimping voortgebring. Stabilisasie met skuim bitumen in plaas van emulsie bitumen toon verlaagde krimping, maar slegs in kombinasie met 2% sement. Die spanning-by-breekpunt, verkose energie en materiaal styfheid wat bereken is vanaf die monotoniese balk toets resultate, het 'n goeie aanduiding van die buigsaamheid gedrag van BGM's verskaf. 'n Hoër bitumen inhoud verhoog die buigsaamheid potensiaal van BGM‟s terwyl 'n toename in sement die buigsaamheid potensiaal van BGM's verlaag. Hierdie projek bied goeie insigte vir beide die krimpings en buigsaamheid gedrag van BGM's, wat in die hersiende ontwerp metode van die SAPDM gebruik kan word. Verhoogde bitumen inhoud verminder die krimping potensiaal en verhoog die buigsaamheid van 'n BGM. Verhoogde sement inhoud aan die ander kant, verhoog krimping en verminder buigsaamheid van BGM's. Die korrekte kombinasie van sement en bitumen in 'n BGM kan dus 'n materiaal produseer met die gewenste buigsaamheidseienskappe en terselfde tyd die krimping tot 'n minimum beperk.

Like in any modern civilization, roads in Iceland have an important role in thedaily lives of inhabitants. Consequently, road quality is of equal importance, butIcelandic roads have shown problems when surface dressing is used where itlooks decent after being paved during summer but then deforming pretty rapidlyafter being hit by elements of winter. Roads in Sweden however, do not seem tohave the same problem.The aim of this study is to minimize this road deformation by examining surfacedressing and aggregates. The Icelandic climate is also a factor to this problemsince the humidity is comparatively high, summers are cool, winters are mild andthe climate is overall challenging. Furthermore, winter thaws are distinctivecharacteristic of the Icelandic weather, which increases strain on the asphalt.An experiment was conducted where the adhesion of surface dressing that iscommon in Sweden was tested with two different aggregates by Vialit plateshock test method. First it was tested with Swedish granite and then withIcelandic basalt. The results from the aggregates were compared where theadhesion with the granite was stronger than with the basalt.Previous study have found that by choosing binder and aggregate that have highadhesivity at low temperature reduces the risk of surface dressing defects,especially when paving takes place in the early and late summer season. Whenchoosing aggregates for road construction the main criteria is cost, thereforeaggregates that are used usually reflect the local geology because transportingaggregates for significant distances is expensive. Concluding from theexperiment, it is not recommended to use the basalt with the Swedish surfacedressing in practice now due to the lesser adhesion compared to the granite.However further research on the asphalt mix with the Swedish surface dressingand the basalt should be conducted.

When an asphalt pavement is subjected to repeated traffic loads punctuated by rest periods, the acquisition of damage is interrupted by molecular relaxation and healing: the restoration of continuity across fractured interfaces. The healing effect is responsible for improved fatigue performance at high temperatures and dominates the laboratory-to-field shift factor in design. The mechanism of healing is not well understood, however. To describe this process, myriad investigations are collated with healing in high polymers, but neglect microstructural changes due to the damage processes that precipitate fracture. Yet, the remnants of deformation drive healing phenomena. An enhanced knowledge of healing and the effect of fracture could allow for the direct application of laboratory fatigue in pavement performance prediction. This thesis develops an understanding of the interrelation between binder structure and crack healing, using electron microscopy and mechanical analyses. Cryogenic microscopy indicates that the bulk is amorphous: phase separation in the form of bi-continuous or discrete structure is catalysed by surface effects including composition-dependent short-range interactions and thermal gradients. Environmental microscopy shows that the creation of a free surface during fracture perturbs the bulk solubility continuum, which stimulates phase separation in the form of interconnected fibrils. This system is sensitive to molecular scission and precludes healing by spatial interference and by reduced potential interaction. Rheological tests confirm the space-bound character of the microstructure and emphasise the requirement for an efficient method to quantify healing. Vialit pendulum tests validate the use of cohesive energy for this purpose and define the effect of fracture temperature: the capacity for healing is reduced by rupture of glassy fractions. Although susceptible to high variability, the outcome of direct tension testing confirms the involvement of crystallisable materials and the reduced proliferation of interfacial molecular interaction due to main-chain scission.

Despite applications of foamed bitumen technology in pavement construction in various places around the world, there are still several aspects about this technology that are not clear. In addition, knowledge on foamed bitumen technology is mainly empirical and lacks scientific basis. This study addresses some of the aspects for foamed bitumen technology such as: Investigation of any effects in binder composition during the production process for foamed bitumen; assessment of the effect of bitumen source on foamed bitumen characteristics; development of a rational method to optimise foamed bitumen characteristics and conditions; evaluation of aggregate particle coating within foamed bitumen mixes; further improvements in the mix design procedure specifically the method of compaction and optimum bitumen content determination stages are suggested.  Fourier transform infrared spectroscopy techniques were used to investigate any changes in bitumen composition after the production process of foamed bitumen. Fourier transform infrared tests were done on foamed bitumen and neat bitumen specimens for two bitumens with similar penetration grades. Foamed bitumen characteristics of three bitumens were established by producing foamed bitumen at temperatures of 150ºC up to 180ºC and foamant water contents of 1, 2, 3, 4 and 5%. From the analysis of variation of foamed bitumen characteristics (maximum expansion ratio and half-life) at different temperatures a new method based on the equi-viscous bitumen temperature to optimize foamed bitumen conditions and characteristics was proposed. Rice density and surface energy concepts were used to evaluate aggregate particle coating with foamed bitumen. A granite aggregate divided into three different size fractions and three sets of foamed bitumen produced from three bitumen penetration grades were used. A gyratory laboratory compaction procedure for laterite gravels treated with foamed bitumen was established using the modified locking concept. Three laterite gravels with different chemical composition were mixed with foamed bitumen produced from one penetration bitumen grade. The resulting mixes were compacted up to 200 gyrations and the corresponding compaction curve defined in terms of height versus number of gyrations noted. In addition, the optimum moisture content requirements at the modified locking point were determined. 3D packing theory concepts, primary aggregate structure porosity and an indirect tensile strength criteria were employed to determine optimum bitumen content for foamed bitumen mixes.  Fourier infrared techniques revealed that foaming did not cause any changes in the bitumen chemistry, implying that the foamed bitumen production process may possibly be a physical process. Characterisation of foamed bitumen produced from three bitumen penetration grades showed that foamed bitumen characteristics (maximum expansion ratio and half-life) were mainly influenced by binder viscosity rather than the source. The equi-viscous temperature seemed to provide a suitable criterion at which foamed bitumen with optimum characteristics could be produced. Rice density results showed that aggregate size fraction, binder expansion ratio and viscosity influenced aggregate particle coating. For the coarser aggregate fraction, results revealed that binder coating seemed to be mainly influenced by temperature. Whilst for fine aggregate fraction the coating was mainly influenced by surface area. Surface energy results revealed that foamed bitumen exhibited better coating attributes than neat bitumen. A new laboratory compaction procedure for laterite gravels treated with foamed bitumen based on the modified locking point was developed. The modified locking point represents the state at which maximum aggregate particle interlock occurs when mixes are compacted in the field. It is based on the iii analysis of the rate of change for the gyratory compaction curve. The compaction curve in this case is defined in terms of compaction height versus number of gyrations. Gradation analysis beyond the modified locking point showed that aggregate particle breakdown occurred. Analysis of the optimum moisture at the modified locking point revealed that the moisture conditions were less than the aggregate optimum moisture conditions. It is recommended that this point be used to determine the optimal compaction characteristics of foamed bitumen mixes.  Aggregate structure porosity and an indirect tensile strength criteria can be used to determine the bitumen content that could be used in design of foamed bitumen mixes. This would reduce the amount of resources required since the bitumen content could be estimated prior to carrying out the actual laboratory work given that the aggregate grading is known. The aggregate structure can be divided (based on 3D packing theory) into oversize, primary, and secondary structures. The primary structure is mostly responsible for carrying loads whilst the secondary structure fills the voids within the primary structure and provides support to the primary structure. The aggregate size particles constituting the primary structure are deduced as a function of standard sieve sizes using the packing theory concepts. The minimum sieve size for the primary structure is proposed as 1 mm. The oversize structure consists of aggregate particles whose size is greater than the maximum size for the primary structure. The secondary structure consists of aggregate particles whose size is below the minimum size for the primary structure. The primary aggregate structure porosity can be used to establish the starting bitumen content; the bitumen content at which this porosity is 50% is chosen as the initial bitumen content. Indirect tensile strength values corresponding to 50% primary porosity are determined as well as the bitumen contents and compared against the recommended minimum values.

QC 20161012

Des polyuréthanes thermoplastiques (TPU) contenant des segments rigides et segments souples d’architecture moléculaire variable sont synthétisés en deux étapes, dont la première fait intervenir un pré-polymère polyuréthane. La microstructure de ces polymères montre qu’une séparation de phases intervient entre segments souples et rigides selon la nature des segments utilisés. Les segments rigides peuvent s’organiser sous deux formes, l’une amorphe et l’autre organisée sous forme d’entités cristallines. La morphologie des TPU dépend de la structure chimique du segment rigide employé. L’incompatibilité entre segments souples et rigides a été mise en évidence à partir de l’analyse des paramètres de solubilité complétée des caractérisations à différentes échelles par des techniques de microscopie (électronique et AFM) et de diffusion des rayons X. Ces polyuréthanes thermoplastiques sont ensuite utilisés pour préparer des mélanges bitume –polymère. Les interactions entre segments du polymère et fractions du bitume sont étudiées en considérant les paramètres de solubilité de chacun d’eux et des mesures de gonflement afin de juger de la miscibilité entre les composés. Des huiles modèles sont employées dans le but de mimer certaines fractions huileuses du bitume, et les segments souples et rigides sont synthétisés séparément afin d’étudier les propriétés de chacune des phases en présence dans le mélange bitume – polymère. La morphologie multi-échelle des mélanges est étudiée en lien avec les propriétés rhéologiques et la structure du polymère utilisé. L’ajout de polymère dans le bitume permet de modifier les propriétés viscoélastiques du bitume au-delà de sa transition vitreuse grâce au gonflement sélectif du polymère par les fractions huileuses. Après avoir mis en évidence et analysé le gonflement sélectif grâce à la prise en considération des paramètres de solubilité et mesuré les tensions interfaciales, nous montrons que la présence d’une phase continue riche en polymère contenant des segments rigides semi-cristallins dans les mélanges conduit à retarder l’écoulement du matériau bitumineux à plus hautes températures. La composition en huile de cette phase riche en polymère dépendra de son affinité avec les fractions du bitume et donc de la structure chimique du polymère. De plus, la teneur du polymère en segments rigides semi-cristallins est aussi un levier permettant d’intervenir sur son affinité avec le bitume et par conséquent sur les propriétés rhéologiques du mélange bitume-polymère
Thermoplastic polyurethane (TPU) containing hard and soft segments with variable molecular architecture are synthesized in two steps, the first one including a polyurethane pre-polymer. The microstructure of theses polymers shows phase separation occurring between soft and hard segments according to the nature of the segments. Hard segments can organize under two forms, either amorphous or crystalline. The morphology of TPU depends on the chemical structure of the hard segment involved. Incompatibility between soft and hard segments was highlighted from solubility parameters analysis, complete with characterization at various scales with microscopy (electron and AFM) and X-ray scattering technics. Theses thermoplastic polyurethanes are used to prepare bitumen-polymer blends. Interactions between the polymer segments and bitumen fractions are studied, considering solubility parameters of each of them and swelling measurements in order to study miscibility between the compounds. Model oils are used in the aims of mimicking some oily fractions of bitumen, and soft and hard segments are separately synthesized to study properties of each phases in the bitumen-polymer mixture. Multi-scale morphology of the blends is studied in connection with rheological properties and structure of the used polymer. The addition of polymer in bitumen allows to modify viscoelastic properties of bitumen beyond its glass transition due to the selective swelling of the polymer by the oily fractions. Having highlighted and analyzed the selective swelling by considering solubility parameters and interfacial tension measurements, we show that the presence of a continuous polymer-rich phase containing semi-crystalline hard segments in the blends leads to delay the flow of the bituminous material at highest temperatures. The oil composition of this polymer-rich phase will depend on its affinity with the fractions of bitumen and thus on the chemical structure of the polymer. In addition, semi-crystalline hard segment content of the polymer is also a key parameter allowing to adjust its affinity with bitumen and consequently on rheological properties of the bitumen-polymer mixture

Nynas produces bitumen at two refineries in Sweden. The bitumen is shipped to seven depots along the swedish coast line, and from the depots special trucks handle the transportation to customers. Recently Nynas has transformed its supply chain and closed down a few depots. At the moment the company is considering a further reduction of the number of depots. In connection to these discussions an analyse of the companys distributionsystem and of possible changes is required. In this thesis an optimization model is developed that simulates Nynas distribution of bitumen from the depots to the customers. The model is used to investigate the required vehicle fleet size for a number of different scenarios, that is with different depots closed down. The question to be answered is, thus, what depots could be closed without any dramatic increase in the required vehicle fleet size? Scenarios where customers are allocated an increased storage capacity are also studied.

The distribution model that is developed is an inventory route planning problem. It is solved by column generation. Each column represents a route and is generated by a subproblem with restrictions on permitted working hours for the truck drivers. Integer solutions are generated heuristically.

Simulations that have been performed with the model reveals interesting differences concerning how the distribution is handled in different parts of Sweden. In western Sweden the transportation planning works well, but the distribution in the central parts of the country could be planned in a better way. Results from simulations also show that the depots in Norrköping and Västerås could be closed down without increasing the vehicle fleet. Probably, the existing vehicle fleet size will be sufficient even with the Kalmar-depot closed down. Nevertheless, Nynas transportation suppliers will have to purchase new vehicles if the Sandarne-depot is to be closed.

Another interesting conclusion that can be drawn from this thesis is that there is a potential for reducing the vehicle fleet size if the storage capacity is increased at a few chosen customers. A considerably small increase in the storage capacity at a few big customers that are located far from the depots will have a great effect.

This doctoral thesis consists of a literature review, presented in two papers, and another six papers describing experimental studies of the influence of different kinds of wax and polyphosporic acid on bitumen and asphalt concrete mixture properties. The literature review should give an extensive description of the field of knowledge concerning wax in bitumen. Effects of wax in crude oil, bitumen and asphalt concrete as well as test methods for studying these effects are described. Theories behind possible mechanisms are also discussed, and commercial wax as additive to bitumen for different purposes included. The experimental parts comprise laboratory studies involving totally five 160/220 penetration base bitumens from different sources, two isolated bitumen waxes, five commercial waxes and one polyphosphoric acid. Asphalt concrete slabs, containing base or modified bitumen were prepared and tested. Binder properties were evaluated using different types of laboratory equipment, such as dynamic shear rheometer (DSR), bending beam rheometer (BBR), differential scanning calorimeter (DSC), force ductilometer, as well as equipment for determining conventional parameters like penetration, softening point, viscosity, and Fraass breaking point. Fourier Transform Infrared (FTIR) spectroscopy and Thin Layer Chromatography (TLC-FID) were used for chemical characterization. The binders were aged by means of the rolling thin film oven test (RTFOT) and pressure ageing vessel (PAV) in combination. Asphalt concrete properties were evaluated at low temperatures using the tensile strain restrained specimen test (TSRST) and creep test at -25°C. Dynamic creep testing was performed at 40°C, as well as complex modulus tests between 0 and 20°C. Binder test results indicated that the magnitude and type of effect on bitumen rheology depend on the bitumen itself, type of crystallizing fraction in the bitumen and/or type and amount of additive used. Bitumen composition was found to be of decisive importance. Adding polyethylene wax or polyphosphoric acid, especially to a non-waxy 160/220 penetration grade bitumen, showed no or positive effects on the rheological behaviour at low temperatures (decrease in stiffness) as well as medium and high temperatures (increase in complex modulus and decrease in phase angle). However, the corresponding positive effects could not be shown in dynamic creep testing (at 40°C) of asphalt concrete mixtures containing these modified binders. Adding FT-paraffin decreased the physical hardening index for all bitumens. Also polyethylene wax and montan wax showed this effect for some bitumens. Slack wax showed a large increasing effect on physical hardening, and polyphosphoric acid none or a minor negative effect. No correlation between physical hardening index (PHI) and wax content by DSC was found in this study, involving both natural bitumen wax and commercial wax. Addition of the commercial waxes used showed no or marginally positive influence on bitumen ageing properties for the bitumens and test conditions used. Comparing asphalt mixture test results to the corresponding binder test results, the effects on asphalt mixtures from adding commercial wax or polyphosphoric acid were less evident. Significant binder physical hardening by BBR could not be confirmed by TSRST.
QC 20101006

Thesis (PhD (Civil Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: In both developing and developed countries, to ensure sustained economic growth the quest for optimal roads performance is an extremely high priority. A global increase in the use of foamed bitumen and bitumen emulsion materials (BSMs) as a solution to roads maintenance, rehabilitation, and upgrading has become evident. This is driven by environmental policies aimed at conserving energy and limiting the exploitation of new borrows pits. It has therefore become imperative that BSMs are used optimally, and, in order to achieve this, practitioners need to understand the mechanisms that influence durability and long-term performance. The changes in the behaviour of materials and the failure mechanisms of BSM mixes are long-term phenomena. This implies that the study of the physicochemical and mechanical properties of the mixes is vital. Therefore, a fundamental understanding of the moisture damage and age-hardening characteristics, which are related to materials’ properties, is required. The main objective of this study is to advance BSM technology by assessing the influence of the selected materials on durability behaviour and long-term performance in all phases of application (i.e. mix design, construction, and in-service condition). This study begins with a comprehensive literature review of research dealing with the interactions of binder and mineral aggregates. The properties of bitumen (foamed bitumen or bitumen emulsion) and mineral aggregates were reviewed. This was followed by review into the colloidal behaviour of foam and emulsion and physicochemical and mechanical interaction with mineral aggregates. Factors influencing the interaction of BSMs were then identified. Finally, the fundamental theories on thermodynamics, hydrodynamics, and electrokinetics were used to describe the step-by-step process by which adhesive bonding and cohesion occur in BSMs. The mixture durability in terms of moisture damage was investigated. To achieve this aim, the physical and mechanical moisture-induced damage process was analysed. The test control parameters were established and a laboratory device to quantify these parameters designed. New moisture conditioning procedures were developed and demonstrated in this study. From the moisture induction simulation test (MIST) procedure, it became evident that pulsing water pressures into compacted and cured BSM mixes simulates the hydrodynamic effect that occurs in the field due to dynamic traffic loading. The different mix matrices typically applicable to the recycling processes – such as Hornfels-RAP and Quartzite crushed stone, stabilised with either foamed bitumen or bitumen emulsion and the addition of active filler (cement or lime) – were investigated. It was found that a new moisture-conditioning procedure using the MIST device and monotonic triaxial testing can distinguish those BSM mixes that are resistant to moisture damage from those that are less resistant. The validation of the MIST and monotonic test results was done using the APT device, which is the MMLS3 wet trafficking test. The results on both tests showed good correlations in evaluating and screening BSMs in terms of moisture susceptibility. Field temperature data was collected and a model to accurately simulate the curing of BSMs was identified and proposed for further investigation and validation. It was found from the field temperature data collected in this study that the temperature gradient on the study site varied according to the depth of the BSMs (that is, 10oC-17oC during winter and 17oC– 47oC during summer). Understanding the influence of the temperature conductivity and rate of evaporation is important for inferring moisture damage and age-hardening behaviour and proper selection of BSMs. The age-hardening behaviour of BSMs is linked to the durability properties and longterm performance of these materials. The fundamental characteristics associated with shortand long-term age hardening were investigated in this study. The short-term dimension involved assessing the age-hardening characteristics of the binder (foamed bitumen colloids and bitumen emulsion droplets) prior to the production of BSMs. The long-term study involved extracting and recovering the binder from the briquettes (made from different mixes) compacted in the laboratory and cores extracted from different field pavement sections which were in service for 8-10 years. The study found that the length of time bitumen is kept in circulation in the laboratory plant at elevated temperature (170oC–180oC) before making BSM-foam contributes to the ageing of the binder, especially after eight hours. The foaming process in itself was found not to alter the bitumen properties. It is recommended that a temperature range between 160oC- 165oC be used for the production of foamed bitumen with softer bitumen. This will not compromise its quality. In addition, the time of circulation of bitumen in laboratory plant should not be longer than three (3) hours. The rheological properties of the bitumen recovered from laboratory briquettes and cores from field pavement show that age hardening on foamed bitumen and bitumen emulsion during in-service life occurred. The ageing also seemed to be dependent on the effect of traffic, with trafficked areas (i.e. on-wheel path and inner-wheel path) experiencing more ageing than untrafficked areas (i.e. between-wheel path). However, the extraction and recovery process was found to be complex, and produce uncertain results. Although the results show that binders in BSMs undergo age hardening, its distinct behaviour in BSM performance was not obvious from the extensive tests carried out in this study. The last part of the study contains its conclusions and recommendations. The study provides an insight into fundamental material durability properties, and this will assist in improving the current procedure for selection, combining and formulation of the mix matrices for BSMs. In addition, the study provides guidelines that will enable practitioners to confidently apply a mix that is durable and long-lasting. The specific durability-related issues addressed in this study are substance for future research. This novel solution to the application of BSMs will benefit all parties involved in the development of pavement recycling technology.
AFRIKAANSE OPSOMMING: Om volgehoue ekonomiese groei te verseker in beide ontwikkelende en ontwikkelde lande, geniet die soeke na die optimale werkverrigting van paaie ’n baie hoë prioriteit. ‘n Wêreldwye toename in die gebruik van skuimbitumen en bitumen-emulsiemateriale (BSMs) as ’n oplossing vir padonderhoud, rehabilitasie en opgradering is merkbaar. Dit word meegebring deur die omgewingsbeleide wat die ontginning van nuwe leengroewe beperk en besparing van energie bevorder. Die korrekte gebruik van hierdie materiale vereis dat die meganismes wat die duursaamheid en langtermyn-werkverrigting daarvan beïnvloed, deeglik verstaan word. Die verandering in materiaalgedrag en falingsmeganismes van BSM materiale is langtermynverskynsels. Dit impliseer dat bestudering van die fisiochemiese en meganiese eienskappe van die mengsels uiters belangrik is. Dis dus voor die hand liggend hoe belangrik vogbeskadiging en verharding met tyd, wat verwant is aan materiaaleienskappe, is. Die hoofdoelwit met hierdie studie is om die vooruitgang van BSM tegnologie te versnel deur dit moontlik te maak om gekose materiale te evalueer op grond van hulle invloed op duursaamheid en langtermyn-werkverrigting in alle toepassingsfases (naamlik mengontwerp, konstruksie en dienstoestand). Hierdie studie begin met ’n uitgebreide literatuuroorsig oor fundamentele begrippe van die karakterisering van interaksie van die bindstof en die minerale-aggregate. Inligting oor bitumen (skuimbitumen en bitumen emulsies) en eienskappe van minerale aggregate is bestudeer. Dit is gevolg deur ’n studie van die fundamentele begrip van die kolloïdale gedrag van skuim en emulsie, asook fisiochemiese en meganiese interaksie met minerale aggregate. Faktore wat die interaksie van BSM-materiale beïnvloed is geïdentifiseer. Die basiese teorie van termodinamika, hidrodinamika en elektrokinetika is daarna gebruik om stap vir stap die proses en formulering van adhesie-binding en kohesie in die BSMs, wat in hierdie studie aangebied word, te beskryf. Die kwantifisering van mengsel-duursaamheid in terme van vogbeskadiging is ontwikkel. Om hierdie doel te bereik, is die fisiese en meganiese proses van beskadiging deur vogindringing geïdentifiseer. Die gekontroleerde parameters is bepaal en ’n laboratoriumapparaat is ontwerp om hierdie parameters te kwantifiseer. Nuwe vogkondisioneringsprosedures is ontwikkel en in hierdie studie gedemonstreer. Van prosedures van voggeïnduseerde sensitiwiteitstoetsing (Engels: moisture induction simulation test (MIST)) was dit duidelik dat pulsering van waterdruk in BSM materiale die hidrodinamiese effek naboots wat in die veld bestaan as gevolg van dinamiese verkeerslaste. Verskillende mengselmatrikse wat tipies is van hergebruik, soos byvoorbeeld hoornfels-hersikleerde asfalt produk (Engels: recycled asphalt product (RAP)) en vergruisde granietklip, met skuimbitumen of bitumenemulsie gestabiliseer en met byvoeging van aktiewe vulmateriaal (sement of kalksteen), is ondersoek. Daar is bevind dat nuwe vogkondisioneringsprosedures (soos bepaal deur MIST apparaat en drie-assige toets) kan onderskei tussen BSM materiale wat weerstandig is teen vogbeskadiging en dié wat minder weerstandig (vatbaar) is. Die geldigheid van die MIST en monotone toetsresultate is bepaal deur gebruik van die APT apparaat wat ’n MMLS3 nat verkeerstoets is. Die resultate van beide toetse toon goeie korrelasie in die keuring van BM materiale in terme van vogvatbaarheid. In hierdie ondersoek is veldtemperatuurdata versamel en die toepaslike model om verouderende BM lae akkuraat te simuleer is geïdentifiseer en voorgelê vir verdere ondersoek en verifikasie. Daar is uit veldtemperatuurdata bevind dat temperatuurgradiënt op die betrokke terrein gewissel het met die dikte van die BSM, naamlik 10oC-17oC gedurende die winter en 17oC-47oC gedurende die somer. Begrip vir die invloed van temperatuuroordragkoëffisiënt en verdampingstempo is belangrik by die afleiding van vogbeskadiging en verharding met ouderdom en die korrekte keuse van BSM materiale.Verouderingsverhardinggedrag van BSMs is verwant aan die duursaamheidseienskappe en langtermynwerkverrigting van hierdie materiale. Die basiese karakteristieke wat met kort- en langtermyn verouderingsverharding geassosieer word, is in hierdie studie ondersoek. Die klem op die kort termyn is geplaas op die verouderingsverhardingsgedrag van die bindstof (skuimbitumen kolloïdes en bitumen-emulsiedruppels) voordat BSMs vervaardig word. In die lang termyn evaluasie het die studie ekstraksie en herwinning van bindstof uit brikette wat in die laboratorium gekompakteer is (van verskillende mengsels) en uit kerns verkry vanaf verskeie plaveiselgedeeltes na 8-10 jaar diens ingesluit. Die ondersoek het bevind dat die tydsverloop waarin bitumen in sirkulasie gehou is by verhoogde temperatuur (170oC-180oC) in die laboratorium-aanleg voordat BSMs vervaardig is, veral indien na 8 uur, bydra tot die veroudering van die bindstof. Die skuimproses op sigself verander nie die bitumeneienskappe nie. Daar word aanbeveel dat temperature tussen die grense 160oC-165oC gehandhaaf word vir produksie van skuimbitumen met sagter bitumen sonder dat die kwaliteit benadeel word en dat die sirkulasietyd nie 2 tot 3 ure behoort te oorskry nie. Die reologiese eienskappe van die herwinde bitumen vanuit laboratoriumbrikette en kerns van plaveisels toon dat ouderdomsverharding van skuimbitumen en bitumen-emulsie tydens die diensleeftyd plaasvind. Die veroudering is skynbaar ook afhanklik van verkeerseffekte, met belaste areas (in wielspoor of binne wielspoor) wat ’n hoër mate van veroudering toon as onbelaste areas (tussen wielspore). Die ekstraksie- en herwinningsproses op sigself was egter bevind as baie kompleks met uiters onseker resultate. Dit het gelei tot onsekere gedrag in terme van ouderdomsverharding van die BSM bindmiddel (skuim of emulsie). Alhoewel resultate toon dat die bindmiddels ouderdomsverharding ondergaan het, is die BSM werkverrigting nie duidelik uit die uitgebreide toetse wat in hierdie studie uitgevoer is nie. Die laaste deel van die studie bevat gevolgtrekkings en aanbevelings. Die studie lewer insig in die fundamentele duursaamheidseienskappe van die materiaal, wat bydra tot verbetering van die huidige prosedure van seleksie, saamstelling en formulering van die mengmatriks vir BSMs. Verder voorsien dit ’n metode wat in die praktyk gebruik kan word om met vertroue duursame mengsels met lang diensbaarheidsleeftye te vervaardig. ’n Nuwe oplossing en vooruitgang in die toepassing van BSMs is daargestel tot voordeel van alle partye betrokke by die ontwikkeling van herwinningstegnologie.