Thesis (M.S.)--University of Nevada, Reno, 2007. / "December, 2007." Includes bibliographical references (leaves 63-66). Online version available on the World Wide Web.

Thesis (Ph.D.) - Carleton University, 2005. / Includes bibliographical references (p. 250-267). Also available in electronic format on the Internet.

Chip and scrub seal treatments are common pavement preservation practices that use asphalt emulsions. Their performance has been studied for several years, yet many questions remain. The primary thesis objective was to study near surface behaviors of flexible pavements that are candidates for seal treatments. This study investigated the ability of the bending beam rheometer (BBR) to detect pavement surface changes due to the application of asphalt emulsion. Estimated stiffness and m-value data was recorded for three asphalt concrete mixtures using mixture beams approximately 120 mm long by 12 mm wide by 7.7 mm thick sawn from the surface of asphalt specimens. One mixture was plant mixed and laboratory compacted, while the other two were field-aged mixtures. This study gauges effect of treating specimens with emulsions commonly used in Mississippi in conditioned and unconditioned states.

No description available.

No description available.

Dissertation (PhD)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The use of foamed bitumen and bitumen emulsion as binders for use in road rehabilitation is gaining favour globally. High-level road facilities through to unpaved roads requiring attention are being treated with these binders due to environmental, economic and practical benefits in the use of cold bituminous mixes. In addition, static and mobile plant with the capability of performing stabilisation using bitumenemulsion and foamed bitumen has become commercially available and widely utilised, as a result of development in recycling technology and lapse in patent rights on foam nozzles. An understanding of the behaviour and failure mechanisms of these cold mixes, as well as sound guidelines for the mix design procedures of cold mixes, especially foamed bitumen, and design guidelines for pavements structures incorporating these materials, are lacking however. Mix designs are carried out primarily on the basis of experience and pavement designs are empirically based. The main objective of this dissertation is to address the need for a fundamental understanding of foamed bitumen and foamed bitumen mixes, and in so doing to develop techniques for adjudicating mixes, optimising their composition and rationalising their design both as mixes and as layers in road pavements. At the same time the exploration of new applications for foamed bitumen and the possibilities for progressive related technology, is a priority. To commence, this study includes an appraisal of most of the literature available on foamed bitumen. This is followed by a fundamental investigation of the colloidal mass of foam that is produced when small quantities of cold water are added to hot bitumen. Factors influencing the quality of the foam are identified and a Foam Index is developed for characterisation and optimisation of the foam. The spatial composition of a cold foamed bitumen mix, including Interaction of the foam with moist mineral aggregate, is also addressed in this dissertation. In particular, the stiffening of the filler mastic using foamed bitumen as binder is analysed. Techniques of optimising the sand type and content in the mix are also developed and guidelines for desired aggregate structures for foam treatment are established. The temperature of the mineral aggregate has been shown to have a profound influence on the behaviour and performance of a foamed bitumen mix. This has been selected as a focal area of further investigation and the research has lead to the development of a new process called "The half-warm foamed bitumen treatment process" that can produce mixes with almost the quality of hot mix asphalt with up to 40% less energy consumption. Other processes developed in this research include the use of cold mix asphaltic blocks for construction of road pavements in developing areas. This technology enhances the use of a high labour component in road construction in an economically competitive manner. The dissertation provides details for mix design and construction of the cold mix blocks. Finally, the study includes models for the performance prediction of foamed bitumen mixes. In particular, foamed mixes that exhibit stress-dependent behaviour have been investigated and models established on the basis of triaxial testing and accelerated pavement testing for the prediction of permanent deformation of such layers under repeated loading. Practical applications of the research findings are summarised in Appendix F. This includes: • methods for optimisation of the foamed bitumen properties, • guidelines for the selection of the ideal aggregate structure for cold foamed mixes, • procedures for carrying out cold mix design in the laboratory (including mixing, compaction and curing), • procedures for manufacturing half-warm foamed mixes in the laboratory, • methods for manufacturing cold mix blocks, and • pavement design methods for road structures incorporating foamed mix layers. Appendix G outlines statistical techniques that are relevant to the design of experiments in pavement engineering including examples of applications of these procedures. The techniques are applied selectively in the relevant chapters of the dissertation. / AFRIKAANSE OPSOMMING: Die gebruik van skuim bitumen en bitumen emulsie as bindmidel in pad rehabilitasie begin groter voorkeur wêreldwyd geniet. Van hoë vlak padfasiliteite tot ongeplaveide paaie wat aandag benodig, word met hierdie binders behandel vanweë die omgewings-, ekonomiese en praktiese voordele wat hierdie koue bitumen mengsels inhou. Voorts is statiese en mobiele masjinerie wat die vermoë het om stabilisasie in die gebruik van bitumenemulsie en skuimbitumen te bewerkstellig, in die handel verkrygbaar. Dit word algemeen gebruik as 'n uitvloeisel van ontwikkelings in herwinningstegnologie en die verslapping van patenteregte op skuim sproeikoppe. 'n Leemte bestaan in die begrip van die gedrags- en swigtingsmeganismes van hierdie koue mengsels, asook goeie riglyne vir die mengselontwerp van koue mengsels en in besonder skuimbitumen, en ontwerpriglyne vir plaveisel strukture waar hierdie materiaal geinkorporeer is. Mengselontwerpe word hoofsaaklik uitgevoer op grond van ondervinding, terwyl plaveiselontwerpe empiries gebaseer is. Die hoofdoel van die verhandeling is om die behoefte vir 'n fundamentele begrip van skuim bitumen en skuimbitumen mengsels aan te spreek, en daardeur tegnieke te ontwikkel vir die be-oordeling van mengsels, optimsering van hul samestelling en rasionalisering van hulontwerp vir beide mengsels en plaveisellae. Terselfdertyd is die ondersoek na nuwe toepassings van skuim bitumen en die moontlikhede van nuwe tegnologie 'n prioriteit. As beginpunt sluit hierdie studie 'n waardeskatting van die meeste literatuur beskikbaar op skuim bitumen in. Dit word gevolg deur 'n basiese ondersoek na die kolloidale massa van skuim wat geproduseer word wanneer klein hoeveelhede koue water by warm bitumen gevoeg word. Faktore wat die gehalte van die skuim beinvloed word uitgewys en 'n Skuim Indeks is ontwikkel vir die karakterisering en optimisering van die skuim. Die ruimtelike samestelling van 'n koue bitumen mengsel, wat die interaksie van die skuim met vogtige minerale samevoegings (aggregate) insluit, word ook aangespreek. Besondere aandag word gewy aan die verharding van die vuiler mastiekgom wat gebruik word as bitumen binder. Tegnieke om die sandtipe en inhoud van die mengsel te optimiseer is ontwikkel en riglyne vir die verlangde samevoegingstrukture (aggregate strukture) vir skuimbehandeling is opgestel. Daar is bevind dat die temperatuur van die minerale aggregaat 'n duidelike invloed op die gedrag en verrigting van 'n skuimbitumen mengsel het. Dit is gekies as In fokuspunt vir verdere studie en die navorsingswerk daarop het gelei tot die ontwikkeling van In nuwe proses wat "Die half-warm skuim bitumen behandelings proses" genoem word. Hierdie proses produseer mengsels wat byna gelykstaande is aan die gehalte van warm gemengde asfalt, maar met tot 40% minder energie verbruik. Ander prosesse wat met dié navorsing ontwikkel is, sluit koue gemengde asfaltiese blokke in, wat gebruik word in die konstruksie van padplaveisel in ontwikkelende gebiede. Hierdie tegnologie bevorder die ekonomiese gebruik van 'n hoë arbeidskomponent in padkonstruksie. Die studie stel besonderhede vir die mengselontwerp en konstruksie vir koue gemengde blokke voor. Laastens sluit die studie modelle in vir die werkverrigtingsvoorspelling van skuimbitumen mengsels. Op basis van drie-assige proewe in die laboratorium en versnelde belasting van paaie is modelle ontwikkel vir skuim bitumen mengsels wat spanningsafhanklike gedrag vertoon (die sogenaamde "granulêre" groep) om die permanente deformasie in die lae as gevolg van herhaalde verkeersbelasting te voorspel. 'n Opsomming van al die praktiese toepassings van die ontwikkelings van die navorsing word in Appendix F verskaf. Dit sluit in: • optimesering van die eienskappe van skuimbitumen, • riglyne vir gewenste samestelling van aggregaat in skuimbitumen mengsels, • ontwerp metodes vir koue skuimbitumen mengsels in die laboratorium (meng, verdigting en curing), • produksie metodes vir half-warme mensels in die laboratorium, • produksie metodes vir blokke wat met koue mengsels gemaak word, en • plaveiselontwerp metodes van strukture wat skuimbitumen lae inkorporeer. Appendix G gee 'n oorsig van statistiese tegnieke wat relevant is vir die ontwerp van eksperimente, insluitend voorbeelde van toepassings van die prosedures in plaveiselingenieurswese. Die tegnieke word selektief toegepas in die relevante hoofstukke van die verhandeling.

Thesis (PhD)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The dissertation presents a design procedure for HMA mixes based on probabilistic and volumetric approaches, hereafter referred to as PAVDAM. Central to PAVDAM is the use of an analytical model for estimating the voids in the mineral aggregate (VMA) of asphalt mixes. Validation of the mix design procedure was done through accelerated pavement testing (APT) with the Model Mobile Load Simulator (MMLS3) at the National Center for Asphalt Technology (NCAT) test track in Opelika, Alabama. In addition, the semi-circular bending (SCB) test was evaluated to serve as an analysis tool to augment the proposed mix design procedure. Non-linear finite element analyses using a quasi-isotropic material model were done using the CAPA-3D finite element system developed at the Technical University of Delft in the Netherlands to better characterise the tensile strength properties of specimens tested with the SCB. PAVDAM is partly based on performance related and analytical procedures such as the Stategic Highway Research Program (SHRP) Superpave and the Belgium Road Research Centre (BRRC) design method. The mix design system was developed based on gyratory compaction procedures. In this regard, the criteria relating gyratory compaction to design traffic as specified in Superpave are used. PAVDAM differs from other mix design methods in that a probabilistic approach is used to account for the variabilities associated with mixture components and properties during the manufacturing stage. It serves as a subset of the volumetric optimisation stage of the mix design process. The development of an analytical model to estimate the VMA of an asphalt mix was the central theme of the dissertation. The analytical model developed is based on modified Aim and Toufar (MAT) packing models developed under SHRP research and used in the concrete industry. The MAT packing models are based on the theory underlying the packing of monosized spheres and the combination of successive binary systems. These models were further refined for use in the asphalt industry. A probabilistic procedure based on the BRRC PRADO packing model is used to account for the influence of size ratio of the successive monosized binary systems. The result was a model that allows an estimation of the VMA of a mix from the gradation of the mix, the voids in the filler and the porosities of the individual aggregate fractions making up the mix. Research was undertaken to couple VMA estimates with gyratory compaction levels. This allowed estimates to be made of the optimum binder contents of mixes for different design traffic levels. The VMA of a mix is difficult to estimate accurately since it is difficult to quantify the factors influencing VMA such as gradation, particle shape, angularity, texture and rugosity. Furthermore, the influence of binder content and compaction must be taken into account. The MAT packing model underestimates the VMA of mixes compared to measured values. For this reason it is necessary to calibrate the model to allow more accurate estimations. More sophisticated models are required to more accurately estimate the VMA of mixes. It is recommended that the development of these be explored further. Asphaltic materials are inherently heterogeneous and there are a large number of factors that influence their volumetric properties. Because of this, Monte Carlo simulation techniques are used in PAVDAM to evaluate the combined effect of the variabilities of significant material properties. The dissertation expands on the different variabilities and the effects of variability on mixture volumetrics and mix design verification. The dissertation outlines the algorithms and procedures used in PAVDAM to estimate the binder content of a mix. In order to validate the PAVDAM model, analyses were done to determine the reliability of specific NCAT MMLS3 test section mixes in terms of densification in the field. A comparison of PAVDAM estimated and field binder contents allowed a ranking of the reliabilities of the different section mixes in terms of field densification at the design traffic level. This ranking compared favourably with that obtained from an analysis of actual densification trends monitored in the field under full-scale trafficking. Initial FEM analyses of the SCB using linear elastic isotropic modelling allowed the development of equations to characterise the tensile strength and modulus characteristics of specimens tested using the SCB. It was emphasized that these equations do not provide a realistic assessment of the strengths or moduli of asphaltic materials. The strengths and moduli of these materials are influenced by strain rates within the materials that cannot be assessed using a simple linear elastic approach. To address this, an alternative FEM analyses using CAPA-3D was undertaken. An approach was adopted to account for the influence of tensile and compressive strain rates on modulus. The analyses made use of a quasi-isotropic material model and it was shown to better characterise the tensile strengths of HMA materials using the SCB. The analyses also indicated that the tensile strengths determined using the equations initially developed based on a linear elastic approach result in strengths that are unrealistically high. It is recommended that further finite element research be done using non-linear material modelling to evaluate the very complex stress-strain conditions within an SCB specimen to better characterise fracture response. It is also recommended that the fatigue characterisation of HMA be explored based on strength tests using the SCB. PAVDAM represents a rational approach to mix design, a shift from experimental empiricism towards scientific fundamentalism. PAVDAM can be used to define the spatial composition of asphalt mixes. The influence of mix component variability may be addressed and reliability assessments of candidate gradations are possible during volumetric optimisation. Furthermore, changes in the volumetric properties of asphalt mixes may be investigated. As such, PAVDAM is a mix design management tool and can only be effective when used as part of a system that closely monitors variability and systematically refines the underlying packing model. / AFRIKAANSE OPSOMMING: Die verhandeling lewer 'n asfalt mengselontwerp metode gebaseer op statistiese en volumetriese metodes, genaamd PAVDAM. PAVDAM gebruik 'n analitise model om 'n skatting te maak van die ruimtes in die aggregaat (VMA) van asfalt mengsels. Stawing van die mengselontwerp metode is gedoen deur vesnelde plaveisel toetse met die Model Mobiele Las Simuleerder (MMLS3) op die National Center for Asphalt Technology (NCAT) se toetsbaan in Opelika, Alabama. Die Semi-Circular Bending (SCB) toets is ook geëvalueer om die voorgestelde ontwerp metode te analiseer. Nielineêre eindige element analise met gebruik van 'n kwasi-isotropiese materiaal model is gedoen met die CAPA-3D eindige element (FEM) stelselontwikkel deur die Tegniese Universitieit van Delft in Nederland om die treksterkte van monsters getoets met die SCB beter te karakteriseer. PAVDAM is deels gebaseer op gedragsverwante en analitise prosedures soos die Strategic Highway Research Program (SHRP) Superpave en die Belgium Road Research Centre (BRRC) ontwerp metodes. Die mengselontwerp stelsel is ontwikkel gebaseer op girator verdigtingsmetodes. Die girator verdigtingskriteria soos voorgeskryf in Superpave is gebruik. PAVDAM verskil van ander mengselontwerp metodes omdat daar gebruik gemaak word van statistiese metodes om die veranderlikhede geassosieer met mengsel komponente en ontwerp prosedures gedurende die vervaardigingsfase. Dit dien as 'n komponent van die volumetriese optimeringsfase van 'n mengsel ontwerp proses. Die sentrale tema van die verhandeling was die ontwikkeling van 'n analitisie model om 'n skatting te maak van die VMA van asfalt mengsels. Die analitise model wat ontwikkel is is gebaseer op gewysigde Aim and Toufar (MAT) pakkingsmodelle ontwikkel as deel van SHRP navorsing en wat gebruik word deur die betonindustrie. Die MAT pakkingsmodelle is gebaseer op die teorie van die pakking van eenvormige groote sfere en die kombinasie van binêre sisteme. Die modelle is verder ontwikkel vir gebruik in die asfaltindustrie. 'n Statistiese prosedure gebaseer op die BRRC se PRADO pakkingsmodel is gebruik om die invloed van groote verhouding (size ratio) van opeenvolgende binêre sisteme in ag te neem. Die gevolg was 'n model wat gebruik kan word om 'n skatting te maak van die VMA van 'n mengsel vanaf die mengsel gradering, ruimtes in die vulstof en die porositeit van die individuele aggregaat fraksies wat die mengsel saamstel. Navorsing is gedoen om die VMA te koppel aan girator verdigtingsvlakke. Die gevolg is dat skattings gemaak kan word van die optimum bindstof inhoude van mengsels vir verskillende verkeer ontwerp vlakke. Dit is moeilik om 'n akkurate skatting van die VMA van mengsels te maak omdat dit moelik is om faktore wat VMA beïnvloed te kwantifiseer, soos byvoorbeeld gradering, partikel vorm, hoekigheid en tekstuur. Die invloed van bindstof inhoud en verdigting moet ook in ag geneem word. Die MAT pakkings modelonderskat die VMA van mengsels in vergeleke met gemete waardes. Daarom is dit noodsaaklik dat die model gekalibreer word om meer akkurate skattings van mengsel VMA te maak. 'n Meer gesofistikeerde model is nodig om meer akkuraat die VMA van mengsels te skat. Dit word voorgestel dat die ontwikkeling van hierdie modelle verder ondersoek word. Asfalt materiaale is inherent heterogeen en daar is 'n groot aantal faktore wat die volumetriese einskappe van die mengsels beïnvloed. Om hierdie rede word gebruik gemaak van Monte Carlo simulasie in PAVDAM om die gekombineerde effek van veranderlikheid in ag te neem. Die verhandeling brei verder uit op verskillende veranderlikhede en die effek van veranderlikheid op die volumetriese einskappe van mengsels en die stawing van die model. Die algoritme en prosedures wat deur PAVDAM gebruik word om 'n skatting te maak van die optimum bindstof inhoud van 'n mengsel word in die verhandeling uiteengesit. Vir stawing van PAVDAM is analises gedoen om die betroubaarheid van NCAT MMLS3 toets seksies in terme van verdigting in die veld te bepaal. Vergelykings tussen PAVDAM geskatte en veld bindstof inhoude het gelei tot 'n rangorde van die betroubaarheid van die verskillende seksie mengsels in terme van verdigting in die veld onder die ontwerp vervoer. Hierdie rangorde het goed vergelyk met die wat gekry is van analise van die werklike verdigtingstendense soos in die veld gemonitor is onder volskaalse verkeer. Voorlopige FEM analise van die 8CB met gebruik van lineêr isotropiese modelering het gelei tot die ontwikkeling van vergelykings om die treksterke en styfheidseienskappe van monsters getoets met die 8CB te skat. Dit word beklemtoon dat hierdie vergelykings nie 'n realistiese skatting van die treksterkte of styfhede van asfalt materiaale gee nie. Die treksterkte en styfhede van die materiaale word beïnvloed deur verplasingstempo's binne die materiaale wat nie deur lineêr elastiese benaderings bepaal kan word nie. Om dit aan te spreek is alternatiewe FEM analise gedoen deur gebruik te maak van CAPA-3D. 'n Benadering is gevolg om die invloed van trek en druk verplasingstempo's op styfheid in ag te neem. Die analise het gebruik gemaak van 'n kwasi-isotropiese materiaal model en dit het 'n beter karakterisering van die treksterkte van asfalt mengsels tot gevolg gehad. Dit word voorgestel dat verdere eindige element navorsing gedoen word met gebruik van nie-lineêre materiaal modellering om die breekgedrag van 8CB monsters beter te kan karakteriseer. Dit word ook voorgestel dat die vermoeiings eienskappe van asfalt mengsels ondersoek word gebaseer op treksterketoetse met gebruik van die 8CB. PAVDAM is 'n rasionele benadering tot mengselontwerp, 'n paradigma skuif weg van empiriese metodes tot wetenskaplik fundamentele metodes. PAVDAM kan gebruik word om die ruimtelike samestelling van asfalt mengsels te definieer. Die invloed van veranderlikheid kan in ag geneem word en betroubaarheidsskattings van kandidaat mengsels is moontlik gedurende die volumetriese optimiseringsfase. Verder kan veranderings in die volumetriese eienskappe van mengsels ondersoek word. As sulks is PAVDAM 'n hulpmiddel vir die bestuur van mengselontwerp en kan net effektief wees wanneer dit gebruik word as deel van 'n stelsel wat die mengselveranderlikheid monitor en sistematies die onderliggende pakkings model verbeter.

Thesis (MEng (Civil Engineering))--University of Stellenbosch, 2007. / Cold mixed asphalt concretes consist of bituminous binder, either cutback or emulsion, and aggregates that have not been heated. Cold mix asphalt is often used due to unavailability of hot mix asphalt in the vicinity of the project and also used for temporary patches. The poorer performance of the materials associated with expensive cold mixes will results in greater overall cost for patching due to increased cost of labour, equipment and traffic control. The main objective of this study was to evaluate performance of proprietary cold mix asphalts available in South Africa. Five products were used in this study, which are Roadfix, Tarfix, Much- Asphalt mix, Asphalt King and Glenpatch. Engineering properties of products were investigated, including volumetric properties, permeability and Indirect Tensile Strength. In addition, for performance properties, accelerated pavement testing using Model Mobil Load Simulator (MMLS3) was carried out. The testing was done dry at 50o C up 20,000 load repetitions. It was found out that all five products have high void contents which range between 15.1% and 23.5%. This makes these cold mix asphalts to be highly permeable. Indirect Tensile Strength values were found to be very low compared to minimum value of 800 kPa specified for Hot Mix Asphalt. Products with emulsion as binder (Asphalt King and Glenpatch) were found to be more susceptible to water damage compared to other mixes with cutback binder. MMLS3 test results showed that Asphalt King was less susceptible to rutting compared to the other four products. In general all products are very highly susceptible to rutting compared to Hot Mix Asphalt.

Thesis (MEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The use of polymer modified binders have increased drastically over the past twenty years. It is generally accepted that current empirical specification tests do not adequately characterise the improvement in binder properties when bitumen is modified with polymers. At the University of Stellenbosch, a programme was initiated to relate binder properties to asphalt mix performance. This study forms part of that programme. This study focuses on three binders and is an attempt to characterise binder properties fundamentally. The binders that were tested are: • 60/70 penetration grade bitumen • SBS modified 60/70 bitumen • Bitumen-Rubber Two rheometers were used to characterise the binder properties: • Sliding Plate Rheometer (SPR) • Dynamic Shear Rheometer (DSR) The Sliding Plate Rheometer was modified to allow testing at elevated temperatures. The modification is described in this thesis. Three types of testing were used to test the binders: • Creep tests (SPR and DSR) • Dynamic tests (Strain and Frequency Sweeps - DSR) • Flow tests (high temperature viscosity tests - DSR) The results of the tests were used to characterise differences between the binders. Shear susceptibility lines were plotted and viscosities calculated from the creep test results; Master Curves and Black Diagrams were plotted from frequency sweep results; flow test results were used to characterise high temperature behaviour. A further development in the asphalt industry is the move towards the development of performance based specifications. A programme has been initiated in this regard and this study forms part of the programme. As a step towards the development of performance based specifications filler was included in this study. BinderlFiller systems were subjected to the same test programme the binders were, to characterise the influence on binder properties of filler addition. Some of the conclusions that were drawn at the end of the study are: • Polymer modification improves binder properties related to rutting. • Filler addition does not affect binder properties negatively. • Shear rate is very important during production of asphalt mixes and construction of asphalt layers containing polymer modified binders. / AFRIKAANSE OPSOMMING: Die gebruik van polimeer gemodifiseerde bitumen het drasties toegeneem oor die afgelope twintig jaar. Dit word algemeen aanvaar dat die huidige empiriese spesifikasie toetse nie die verbetering in bindmiddeleienskappe van polimeer modifisering aanvaarbaar karakteriseer nie. 'n Program is geïnisieer by die Universiteit van Stellenbosch om 'n verband te vind tussen bindmiddeleienskappe en asfaltmengseleienskappe. Hierdie studie vorm deel van die program. Hierdie werk fokus op drie bindmiddels en is 'n poging om die bindmiddeleienskappe fundamenteel te karakteriseer. Die bindmiddels wat gebruik is in hierdie werk, is: • 60/70 penetrasiegraad bitumen • SBS gemodifiseerde 60/70 bittimen • Bitumen-Rubber Twee reometers is gebruik om bindmiddeleienskappe te karakteriseer: • Glyplaat Reometer (SPR) • Dinamiese SkuifReometer (DSR) Die glyplaat reometer is aangepas om toetse by hoër temperature te doen en die aanpassing wat gemaak is word in die tesis beskryf. Drie tipes toetse is uitgevoer om die bindmiddels mee te toets: • Kruiptoetse (SPR en DSR) • Dinamiese toetse (DSR) • Vloei toetse (DSR) Die resultate van die toetse is gebruik om die verksille tussen die bindmiddels te kwalifiseer. Verskillende grafieke en figure is getrek van die resultate om die onderskeie bindmiddels te karakteriseer. Die beweging weg van empmese spesifikasies na werkverrigting gebaseerde spesifikasies in die asfalt industrie is 'n verder nuwe ontwikkeling. 'n Program is geïnisïeer ten opsigte hiervan en hierdie werk vorm deel van die program. As 'n stap in die ontwikkeling van die werkverrigting gebaseerde spesifikasies is 'n vuIler ingesluit in die toetsprogram. Bindmiddel/vuIler stelsels is onderwerp aan dieselfde toetse waaraan die bindmiddels onderwerp is om die invloed van die vuIler op die bindmiddels te karakteriseer. Sommige van die gevolgtrekkings waartoe gekom is aan die einde van die tesis, is: • Polimeer modifisering verbeter bindmiddeleienskappe met betrekking tot wielsporing. • Die toevoeging van vuIler affekteer nie die bindmiddeleienskappe negatiefnie. • Die vervormingstempo is van groot belang wanneer asfaltmengsels gemeng en lae gebou word van mengsels wat polimeer gemodifiseerde bitumen bevat.

O uso de geossintéticos em rodovias tem recebido considerável atenção nas últimas décadas. A utilização de materiais alternativos na reabilitação de pavimentos flexíveis, utilizando sistemas anti-reflexão de trincas, tem se destacado entre pesquisas acerca deste tema. A experiência internacional mostra que o uso de geotêxteis não tecidos, aliados ao ligante asfáltico, tem demonstrado bom desempenho em obras de restauração de pavimentos. No entanto, o sucesso desta técnica depende diretamente do entendimento do comportamento dos geotêxteis quando impregnados com asfalto. Neste contexto, este estudo avaliou diferentes geotêxteis não tecidos frequentemente utilizados em sistemas anti-reflexão de trincas, enfatizando o ganho de rigidez à tração e a redução da permeabilidade destes materiais após a impregnação com o ligante asfáltico. Amostras de geotêxteis não tecidos de poliéster e polipropileno foram impregnadas com emulsão asfáltica catiônica de ruptura rápida. Ensaios de tração foram realizados de acordo com a ABNT - NBR 12824/93 e os ensaios de transmissão de vapor d\'água foram conduzidos conforme as especificações da ASTM - E96M/05. Os resultados dos ensaios de tração em geotêxteis impregnados mostraram um aumento significativo dos valores de rigidez à tração para os níveis de deformação analisados. Resultados revelaram também um elevado aumento nos valores de rigidez à tração para níveis de deformação da ordem de 0,03%. Ensaios de transmissão de vapor d\'água demonstraram que a emulsão asfáltica aplicada sobre os geotêxteis permite uma drástica redução nos valores de permeabilidade normal do material, podendo transformar este sistema em uma barreira impermeável. / The use of geosynthetics in roadway systems has received considerable attention over the past decades. Paving fabrics have been used for rehabilitation of pavements to reduce propagation of cracks and to extend pavement life. In addition, the success of this technique depends directly on the understanding of the geotextiles behavior when impregnated with asphalt. I this sense, this study evaluated different nonwoven geotextiles frequently used in the anti-reflective cracking systems, focusing on initial stiffness gain and permeability reduction. Virgin and impregnated specimens of polyester and polypropylene nonwoven geotextiles were used. Cationic rapid setting emulsified asphalt (CRS) was used as asphalt binder. Wide-width tensile tests were performed in accordance with ABNT - NBR 12824/93 and water vapor transmission tests (WVT) were performed according to ASTM E96M/05. The results of tensile tests on impregnated geotextiles showed significantly increase in tensile stiffness values. Results also showed high increase in stiffness values at strain levels less than 0.03% and decrease on stiffness gains with the increase of strains. Water vapor transmission tests demonstrated that cationic asphalt emulsion applied on nonwoven geotextiles allows a drastic reduction in permeability values and may turn this system in a low permeability barrier.