Дисертації з теми "Polymer-modified binder"

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.

Polymers are added to asphalt binders primarily to stiffen the binder at higher temperatures and thus to protect the pavement against rutting at summertime temperatures early in the pavement's life. Also, it has been noted that polymers typically increase the ductility of a binder and that some polymer-asphalt combinations are especially effective. Furthermore, it is hypothesized that enhancing a binder's ductility, and maintaining this enhancement with binder oxidative aging, contributes to enhanced binder durability in pavements. However, polymer-asphalt interactions and how they might contribute to improved binder performance is not well understood. The goal of this work was to probe the relationship of polymer morphology on asphalt binder rheology and mixture durability. Experiments were conducted on asphalt mixtures and binders, and as a function of oxidative aging. PFC mixtures, which are an open mixture designed to allow enhanced water drainage, were of specific interest. These mixtures were tested for Cantabro Loss, an indicator of a mixture's likelihood of failure by raveling. Asphalt binders were tested using dynamic shear rheometry (DSR), which provided the DSR function, (G' /η'/G'), a measure of binder stiffness that includes both the elastic modulus and the flow viscosity), ductility (used to measure the elongation a binder could withstand before failure), gel permeation chromatography (GPC), used to estimate the relative amount of polymer) and fluorescence microscopy (used to image the polymer morphology in the asphalt binder). From these data, relationships were assessed between binder morphology and binder rheology and between binder rheology and mixture durability, all as a function of binder oxidative aging. Polymer morphology related to ductility enhancement. Polymer morphology related to a change in the DSR function, relative to the amount of polymer, as measured by the polymer GPC peak height. Cantabro loss correlated to the DSR function (R2=0.963). The overall conclusion is that polymer morphology, as indicated by fluorescence microscopy, relates to both the rheological properties of the binder and the Cantabro loss of the mixture. These relationships should yield a better understanding of polymer modification, increased mixture durability (decreased raveling) and improved rheological properties (DSR function and ductility).

Orientador: Wagner dos Santos Oliveira
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: Este trabalho apresenta resultados o estudo de pesquisa e desenvolvimento de misturas de polímeros em cimento asfáltico de petróleo. O asfalto é um excelente material aglutinante utilizado na construção de rodovias e vias urbanas, entretanto o aumento do número de veículos comerciais e da carga transportada por eixo tem levado a deteriorização prematura dos pavimentos. Os resultados obtidos mostram que o polímero do tipo estireno-butadieno-estireno quando incorporado ao asfalto traz melhoria nas propriedades físico-químicas e desempenho, sobretudo quando em contato com cargas pesadas, em climas quentes, tornando-o resistente à deformação permanente, pela preservação de sua flexibilidade e elasticidade. A incorporação de 4% polímero tipo estirenobutadieno-estireno ao asfalto resultou na melhoria de suas propriedades, principalmente a resistência ao envelhecimento, aumento no ponto de amolecimento, ganho de recuperação elástica. O asfalto modificado é uma boa solução, pois embora aumente os custos iniciais do produto, resulta em um ótimo custo benefício, reduzindo a necessidade de manutenção das rodovias ou vias urbanas ao longo dos anos
Abstract: This paper presents laboratorial research results comprising developing project of polymer mixtures in petroleum asphalt cement. The asphalt is an excellent binding material used in the highway constructions and unban roads, however the increase of the commercial vehicles number and the load transported by axle have led to the premature pavements failure. The laboratory outcomes obtained show that the SBS polymer, which is embedded to the asphalt, brings improvement in the physico - chemical properties and performance mainly for its good performance under heavy loads in hot climates becoming resistant to the permanent deformation, but maintaining the flexibility as the asphaltic concrete providing elasticity. The SBS polymer is a good solution, although it increases the initial costs of the product, however with a great costeffective regarding the maintenance of the highways or unban roads over the years
Mestrado
Ciencia e Tecnologia de Materiais
Mestre em Engenharia Química

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
O desenvolvimento de novas metodologias no campo da engenharia rodoviÃria tem sido uma preocupaÃÃo, visando à melhoria da qualidade das vias pavimentadas, tornando-as mais seguras e resistentes. Algumas inovaÃÃes introduzidas nesta Ãrea tem sido praticadas com a aplicaÃÃo de ligantes asfÃlticos (LAs) modificados, que tem demonstrado melhorar o desempenho destes, contribuindo para a reduÃÃo da formaÃÃo das trilhas de roda e das trincas tÃrmicas. Neste estudo, o ligante asfÃltico (LA) brasileiro oriundo do Campo Fazenda Alegre foi modificado por copolÃmero de etileno e acetato de vinila (EVA) virgem, resÃduo da indÃstria de calÃados (EVAR) e fibra de coco (FC). Aditivos, como o lÃquido da castanha de caju (LCC) e o Ãleo extensor (OE) foram utilizados para melhorar a compatibilidade da mistura. O polÃmero e os aditivos foram caracterizados atravÃs de espectroscopia no infravermelho, termogravimetria e calorimetria exploratÃria diferencial. A avaliaÃÃo dos espectros FTIR dos ligantes apÃs envelhecimento simulado em estufa RTFOT, mostraram que os ligantes modificados com EVAR e EVA/FC foram mais resistentes ao processo oxidativo, provavelmente, devido à presenÃa de aditivos, como o carbonato de cÃlcio, na composiÃÃo do resÃduo. As curvas termogravimÃtricas dos LAs modificados apresentaram comportamento semelhante ao ligante puro. As propriedades reolÃgicas tambÃm foram avaliadas atravÃs de ensaios em: viscosÃmetro e reÃmetro de cisalhamento dinÃmico (DSR). O envelhecimento, de maneira geral, provoca aumento da rigidez e da viscosidade, porÃm as curvas mestras indicaram que o efeito do envelhecimento à mais expressivo nas temperaturas intermediÃrias a altas, e aumentaram a elasticidade ao longo do espectro de frequÃncias. A viscosidade zero shear (ZSV) obtida pelos modelos de Cross e Williamson apresentou-se mais elevada do que o modelo de Carreau. AlÃm disso, as imagens obtidas no microscÃpio de forÃa atÃmica (MFA) mostraram que o polÃmero EVA intumesceu devido à absorÃÃo de fraÃÃo aromÃtica do ligante, rompendo a estabilidade coloidal. Assim sendo, a adiÃÃo do Ãleo extensor preveniu a separaÃÃo de fases. Para o ligante modificado com EVAR, a mistura apresentou boa estabilidade à estocagem somente apÃs adiÃÃo de Ãleo extensor. A presenÃa do LCC e OE mostrou melhorar a susceptibilidade tÃrmica dos ligantes modificados.
The development of new methodologies in the field of road engineering has been a concern, aimed to the improvement of the quality of paved roads making them safer and more durable. Some innovations introduced in this area have been practiced with the application of modified asphalt binder (AB), demonstrated to improve asphalt binder performance, contributing to the reduction of the formation of wheel tracks and of thermal cracking. In this study, the Brazilian asphalt binder from Fazenda Alegre oil reserve was modified by virgin ethylene vinyl acetate copolymer (EVA), residue of the industry of footwears (EVAR) and coir fiber (CF). Additives, such as the cashew nut shell liquid (CNSL) and extensor oil (EO) were used to improve the compatibility of the mixture. The polymer and additives were characterized by means of infrared spectroscopy, termogravimetry and diferencial scanning calorimetry. The evaluation of the spectra FTIR of the binders after simulated aging in RTFOT, showed that the modified binders with EVAR and EVA/FC were more resistant to oxidative hardening, probably due to the presence of the additive, in the composition of the residue, such as the calcium carbonate. The termogravimetry curves of the modified ABs presented behavior similar to the pure binder. The rheological properties were also evaluated by tests with the viscometer and the dynamic shear rheometer (DSR). In general, ageing causes an increase in stiffness and viscosity, however the master curves indicated that the effect of aging is most significant in the intermediate to high temperatures and increases the elasticity along the spectrum of frequencies. The zero shear viscosity (ZSV) obtained by the models of Cross and Williamson was higher than the Carreau model. In addition atomic force microscopy (AFM) images were obtained in the showed that the EVA polymer sweeling suggest that part of the maltenic fraction of the binder was absorbed by the polymer. For the binder modified with EVAR, the mixture showed good stability only after the addition of the extensor oil. The presence of CNSL and EO improved the thermal susceptibility of the modified binders.

Este trabalho apresenta alguns resultados de pesquisa laboratorial compreendendo projeto de dosagem, comportamento mecânico da mistura SMA (Stone Matrix Asphalt - Matriz Pétrea Asfáltica), bem como, aspectos executivos relacionados ao desenvolvimento de um trecho experimental em SMA para revestimento de pavimentos. Os resultados de laboratório obtidos mostram que o SMA é um revestimento asfáltico que pode apresentar bom desempenho sob cargas pesadas em climas quentes, pois estas misturas são muito resistentes à deformação permanente, mas preservam a flexibilidade como os concretos asfálticos densos. O SMA é uma solução bem conhecida para tráfego pesado na Europa e mais recentemente na América do Norte. O SMA também tem sido empregado para aumento de aderência em pista molhada e para redução de ruído.
This research presents laboratory test results of mixture design, mechanical behavior of SMA (Stone Matrix Asphalt), as well as some construction aspects regarding to development of Brazilian road trial section as a new bituminous surface course to pavement construction or maintenance.The laboratory results show that SMA can perform very well in hot climate under heavy load conditions due to the mixture to be very resistant against permanent deformation but still flexible like dense asphalt concrete. The SMA is a well Known solution for heavy traffic in Europe and, more recently, in North America. The SMA is also employed to increase the adherence in wet conditions and for noise reduction.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The study in question has researched the chemical and rheological properties of pure asphalt binder in Manaus (CAP 50/70-REMAN), and when modified with agents: synthetic polymer - a styrene-butadiene copolymer (SBS), natural fiber of fruits rind of Couepia edulis (Prance) (FCC) and antioxidant additive - fat Virola surinamensis - ucuúba (GU), aiming to bring benefits to the asphalt used in the region, as from the oxidative stress and heat, as well as a better performance of asphalt mixtures used in the process champion. Were determinate the properties of degradation and stabilization by thermal analysis - Termogravimetira (TG) and Differential Scanning Calorimetry (DSC), rheology, through Rheometer Dynamic Shear (Shear Rheometer Dynamical - DSR) under the parameters established in the specifications SUPERPAVE the aging process by thermoxidized (RTFOT) beyond the traditional characterization advocated by the National Petroleum Agency - ANP. The addition of modifying agents affected the physical, chemical and rheological properties, the main results: reduction in penetration rate, increase in softening point, good thermal stability and miscibility with the CAP, a significant increase in G* at low frequencies and decrease in tan δ, and the elevation of viscosity for the modified binders, but less pronounced by the presence of additive (GU).
comercializado em Manaus (CAP 50/70-REMAN), e quando modificado com os agentes: polímero sintético - copolímero de estireno e butadieno (SBS), fibra natural oriunda da casca da castanha de cutia (FCC) - Couepia edulis (Prance) e com aditivo antioxidante - gordura de Virola surinamensis ucuúba (GU), visando trazer benefícios ao asfalto utilizado na região, quanto ao efeito oxidativo e térmico, bem como quanto a um melhor desempenho das misturas asfálticas empregadas nas vias manauaras. Foram determinadas as propriedades de degradação e estabilização, pela análise térmica Termogravimetira (TG) e Calorimetria Exploratória Diferencial (DSC), o comportamento reológico, por meio do Reômetro de Cisalhamento dinâmico (Dynamical Shear Rheometer - DSR) segundo os parâmetros estabelecidos nas especificações SUPERPAVE, o envelhecimento pelo processo termoxidativo (RTFOT) além da caracterização tradicional preconizada pela Agência Nacional de Petróleo ANP. A adição de agentes modificadores afetou as propriedades físicas, químicas e reológicas, tendo como principais resultados: redução nos índice de penetração, aumento no ponto de amolecimento, boa estabilidade térmica e miscibilidade com o CAP, aumento significativo no G* em baixas freqüências e diminuição na tan δ, além da elevação da viscosidade para os ligantes modificados, porém menos pronunciada pela presença de aditivo (GU).

The increase and change in traffic loading in recent years has resulted in the introduction of a new range of high performance asphalt binders. These new binders known as modified asphalt binders, have a more complex behavior than traditional binders. A review of the current mathematical models shows that most of them suffer from different drawbacks that make them inadequate for their intended application. To describe the behavior of straight and modified binders in the thermorheologically simple linear viscoelastic region, two models are proposed. Models to characterize the absolute value of the complex shear modulus (|G*|) and the phase angle (d) were developed using the matching function approach and validated by an experimental program. The dynamic mechanical properties of two typical paving grade binders and three modified binders were tested at intermediate and high service temperatures. Short-term and long-term aging were simulated by the rolling thin film oven test and the pressure aging vessel test, respectively. A dynamic shear rheometer with parallel plate configuration was used to conduct the dynamic mechanical tests at frequencies between 0.06 to 188.5 rad/sec and temperatures ranging from 5 to 75°C. Prior to the frequency sweeps, strain sweeps were performed to establish the linear viscoelastic region. Results indicated a strong susceptibility to the defined strain at intermediate temperatures; however, strain susceptibility was less pronounced at high temperatures. Frequency sweeps were then conducted at a constant strain corresponding to greater than 95% of the initial complex shear modulus as established by AASHTO TP5 for straight asphalts. The Time-Temperature Superposition Principle was used to construct the master curves. The shift factors were determined based on the complex shear modulus master curves and verified for the phase angle, storage shear modulus and loss shear modulus.

After construction of the master curves, non-linear regression was used to fit the proposed models to the experimental data. Comparison between the measured and predicted values indicated a good agreement for frequencies higher than 10^-5 rad/sec. The phase angle model was found to adequately describe unmodified binder with a small percentage of errors (less than 6%). On the other hand, the phase angle model was found unable to simulate the plateau region observed for polymer-modified binders. However, the error in this case was found to be relatively small (from zero to 10%).

The ability of the models to estimate other viscoelastic functions, e.g. storage shear modulus (G'), loss shear modulus (G"), and relaxation spectrum (H(t)), was found to be adequate.
Master of Science

Current mathematical models, developed on straight asphalt binders, are inadequate to characterize the frequency dependence of response of polymer-modified asphalt binders. In an earlier study at Virginia Tech, mathematical models were developed to predict the storage and loss shear moduli of polymer-modified binders. However the model developed for the loss shear moduli is limited at high frequency (G" less than or equal to 10^7.5 Pa). This thesis presents a statistical modeling of loss shear modulus of polymer (random copolymers and thermoplastic block copolymers) modified binder. Data from dynamic mechanical analysis on modified binders, at temperatures between 5 and 75°C and frequencies ranging from 0.06 to 0188.5 rad/s, were reduced to dynamic master curves of moduli, and used to develop the model. Twenty-one polymer-binder blends prepared and tested earlier at Virginia Tech where included in the study. Realistic characterization of loss shear moduli values was obtained using the Gompertz statistical model. The model was validated by using mean square error of prediction (MSEP) in which a second set of frequency data was input in the model to obtain the moduli values, which were compared to the measured data of the second set. Although this model was successfully tested for shear loss modulus prediction of polymer-modified binders, caution should be exercised when it is applied, as such a model should be able to predict the storage modulus for a known phase angle.
Master of Science

O uso de asfaltos modificados com polímeros tem crescido significativamente nas últimas décadas em função do aumento da densidade de tráfego, da carga por eixo nos veículos e da pressão dos pneus. Estes ligantes proporcionam o aumento a vida útil e a redução do custo de manutenção das rodovias. Os polímeros mais utilizados na modificação de asfalto são os copolímeros em bloco de estireno-butadienoestireno. Esta tese avaliou os efeitos de diferentes agentes compatibilizantes (óleos) e agentes de ligação no comportamento reológico de misturas asfálticas modificadas com copolímeros de estireno-butadieno-estireno, bem como a influência da sua estrutura, se linear ou radial. Para isto foram realizados análises convencionais e testes em reômetro de cisalhamento dinâmico. Os dados obtidos permitiram evidenciar a eficácia do óleo de xisto como agente compatibilizante, proporcionando excelente dispersão do polímero na matriz asfáltica e estabilidade a estocagem a altas temperaturas. Este óleo apresenta-se como uma opção tecnicamente viável para o óleo aromático atualmente em uso no mercado. Foi também verificado que o uso de enxofre como agente de ligação tem um efeito altamente positivo nas propriedades do ligante modificado, com significativa redução da tan ō, da deformação após aplicação de cargas cíclicas e elevação do módulo complexo, o que contribui para obtenção de pavimentos com maior resistência a deformação e ao trincamento por fadiga.
The use of polymer modified asphalts has grown significantly in the last decades due to the increase in traffic density, axle loading in vehicles and tyre pressure. These binders favor the increase of pavement life and the reduction of its maintenancement costs. The most used polymer for asphalt modification is styrene-butadiene-styrene blocked copolymers. This thesis evaluated the effects of different compatibilizers and crosslinkers on rheological behavior of styrene-butadiene-styrene copolymer modified asphalt binders, as well as the influence of its structure, linear or radial. Binder’s characteristics were determined by conventional analysis and tests in dinamic shear rheometer. Data obtained provided evidence of the positive effect of sulfur as crosslinker in modified binders properties, with high tan ō reduction, complex modulus increase and deformation reduction after application of cyclic loads, characteristics that turn possible the existence of pavements with greater rutting and fatigue resistance. It was also verified the shale oil efficacy as a compatibilizer agent, providing an excellent polymer dispersion inside asphalt matrix and a stable storage binder at high temperatures. This oil can be considered as a technical available option to aromatic oil presently in use at pavement industry.

Sammanfattning på svenska: Målet med projektet var att utveckla ett system av disperserade bindemedel för non-wovenindustrin som inte förutsätter omfattande förändringar i befintliga processer. Bindemedlet ska vara biobaserat, bionedbrytbart och endast bestå av byggstenar som är matkontaktsgodkända av FDA och BFR. Ett disperserat system möjliggör en hög torrhalt tillsammans med en låg viskositet som i kombination med stor anpassningsbarhet kan konkurrera med fossila bindemedel på marknaden. Denna studie behandlar användande och modifiering av vattenlösliga biopolymerer för utveckling av ett disperserat system med förmågan att binda samman fibrer i ett non-wovenmaterial. Flertal analytiska metoder och observationer används, som Fourier transform infraröd spektroskopi (FTIR), laddningsdensitet, viskositet och optisk mikroskopi, för att mäta framgången av konceptet. Olika modifieringar och ympningsstrategier användes under projektet och deras inverkan på biopolymerer diskuteras.
The aim of the project was to develop a dispersed binder as a drop-in solution for non-woven industry. The binder should be bio-based, biodegradable and consist only of FDA and BFR food contact approved components. A dispersed system enables the binder to have a high solid content while having a low viscosity. This feature, in combination with a binder with tunable properties, can be a competitive alternative for the fossil-based binders in the market.  This study focuses on the use and modification of biopolymers with binding capacity to form a dispersed system from water-soluble biopolymers. The success of the reaction was evaluated by using a multitude of analytical methods and observation, such as Fourier transform infrared spectroscopy (FTIR), charge distribution and viscosity measurements. Several modification strategies and grafting agents were used and their impact on the biopolymer is discussed.

Este trabalho teve como objetivo avaliar as vantagens ou desvantagens de utilizar-se asfalto modificado com polímero em misturas densas com seixo rolado como agregado graúdo. Para o experimento foram moldados setenta e cinco corpos-de-prova com asfalto convencional (CAP-40) e setenta e cinco corpos-de-prova com asfalto modificado (BETUFLEX B 65/60) e avaliados à luz dos ensaios Marshall, fluência por compressão uniaxial estática à 40ºC, resistência à tração por compressão diametral e módulo de resiliência por compressão diametral à 25ºC. Os resultados dos ensaios Marshall e de resistência à tração acusaram um melhor desempenho das misturas com asfalto modificado. As relações MR/'sigma tal' encontradas para ambas as misturas sugerem, a princípio, um melhor comportamento para as misturas modificadas. Os resultados dos ensaios de fluência por compressão uniaxial estática, no que tange à deformação elástica, detectou também uma performance superior das misturas com asfalto modificado em três teores de ligante dos cinco teores analisados, entretanto, para as demais propriedades, deformação total, deformação viscoplástica e módulo de fluência as misturas com asfalto convencional sairam-se melhor.
This research intends to analyze the advantages of hot-mix asphalt mixtures composed by polymer modified binder and gravel in relation to those made with conventional binder. To achieve the objective, there were compacted seventy five specimens with conventional binder and seventy five specimens with SBS polymer modified binder (BETUFLEX B 65/60) and were performed Marshall tests, static creep (40oC) tests, indirect tensile strength tests and resilient modulus by indirect tensile (25oC) tests. The results of Marshall and tensile strength tests showed a better performance of the polymer modified asphalt mixes than that presented by the conventional asphalt ones. The results from the relation of resilient modulus by indirect tensile and indirect tensile strength tests probably showed that the modified asphalt mixes have the best performance. The elastic strains from static creep tests also showed a better performance of the polymer modified mixes in three of the five binder contents, however, the others properties from static creep tests like as total strain, viscoplastic strain and creep modulus showed that the conventional asphalt mixes have the best performance.

Este trabalho teve por objetivo o desempenho de misturas asfálticas densas utilizando um ligante convencional (CAP-20) e o mesmo ligante modificado com polímeros tipo SBS, produzido sob o nome comercial de BETUFLEX B 65/60, através dos ensaios Marshall, fluência por compressão uniaxial estática e dinâmica, resistência à tração por compressão diametral e módulo resiliente pro compressão diametral dinâmica, em misturas compactadas com uma mesma faixa granulométrica e diferentes teores de ligantes. O ensaio Marshall apresentou, para as misturas preparadas com asfalto modificado, valores maiores de estabilidade para a maioria dos teores, apesar de valores elevados de fluência em todos os teores analisados. Os resultados de deformação do ensaio de fluência por compressão uniaxial não distinguiram claramente o efeito da adição de polímeros em misturas asfálticas, ao contrário do observado no ensaio dinâmico, onde as deformações foram consideravelmente menores para a maioria dos teores analisados. Os resultados do ensaio de resistência à tração por compressão diametral mostram um desempenho superior da mistura modificada. O ensaio de módulo resiliente por compressão diametral dinâmica indicou, à temperatura de 25ºC, valores menores para a mistura com asfalto modificado, não sendo notada, entretanto, uma diferenciação de desempenho nas temperaturas de 5ºC e 40ºC. A modelação matemática das curvas de fluência e de recuperação às equações constitutivas de alguns modelos visco-elásticos básicos detectou uma diferenciação entre os valores de alguns elementos constitutivos, tanto do ensaio dinâmico, quanto do estático.
The purpose of this study is to evaluate the performance of asphalt mixes using conventional binder and the same binder modified with SBS polymer (Betuflex B 65/60) based on Marshall test, static and dynamic creep tests, indirect tensile strength test and resilient modulus by indirect tensile test, with the same granulometric composition and different binders contents. In Marshall test, polymer modified asphalt mixes presented better stability performance than conventional asphalt mixes in most of binders contents, despite of the higher flow values obtained for all binders contents. The static creep test results indicated that this test does not clearly distinguish the effect of polymer in asphalt mixes while the results of dynamic creep test indicated the opposite, i. e., polymer modified asphalt mixes deformations are smaller for most of the asphalt binders contents studied. The indirect tensile strength test results showed a better performance of modified asphalt. The results of resilient modulus by indirect tensile test at 25°C showed smaller values for modified asphalt, while the results at 5ºC and 40ºC did not show differences between the asphalt mixes. The mathematics modelling of the creep and recovering curves according to constitutive equations of some basic visco- elastic models showed a difference between the values of some constitutive elements in both cases, dynamic and static tests.

Dissertação de mestrado em Urban Engineering
Asphalt binders used in road pavements basically age in two phases, the short-term aging and the long-term aging. Short-term aging occurs in binders due to mixing, transporting, placing, and compaction of asphalt mixtures, while long-term aging occurs in situ during the lifetime of the pavement. The effect of short-term and long-term aging on the binder reveals in its chemical structure, mainly by increasing the rate of oxidation, and in its physical or rheological properties by hardening. The main aim of this work was the study of the short-term aging, especially addressing the assessment of polymer modified asphalt binders. In fact, these binders are being increasingly used, but the evolution of their properties during aging is still not well known. A 35/50 penetration grade unmodified bitumen (B1), a 70/100 penetration grade Ethylene Vinyl Acetate (EVA)-modified bitumen (PmB1), and a 70/100 penetration grade High-Density Polyethylene (HDPE)-modified bitumen (PmB2) were aged applying two different methods. In one method, the binders were exposed to 75-min in RTFOT testing (binder aging). In the other method, the binders were used to produce asphalt mixture samples, and the aged binders were recovered (short-term aging of the mixture and binder recovery) after mechanical testing of samples. The rheological properties of all binders were assessed for each one of their states, namely unaged, after-RTFOT aging, and after-recovery aging. These rheological measurements after RTFOT aging obviously indicated an increase in the binders’ stiffness. However, the rheological results after-recovery appeared to be unreasonable. Hence, the binders PmB1 and PmB2 were also subjected to DSC testing trying to explain these unexpected results. DSC analysis indicated that the polymers were absent from PmBs after recovery process. Yet, the FTIR analysis had demonstrated that the recovered bituminous parts of PmBs were indeed aged chemically when the mixtures were produced and compacted.
Os ligantes betuminosos utilizados na pavimentação de estradas envelhecem basicamente de duas formas, a curto prazo e a longo prazo. O envelhecimento de curto prazo ocorre nos ligantes devido à produção, transporte, colocação e compactação das misturas betuminosas, enquanto o envelhecimento a longo prazo ocorre in situ durante o período de vida do pavimento. O efeito do envelhecimento do ligante a curto e a longo prazo revela-se na sua estrutura química, principalmente através do aumento da taxa de oxidação, e nas suas propriedades físicas ou reológicas pelo aumento da rigidez. O objetivo deste trabalho foi o estudo do envelhecimento a curto prazo, e será especialmente orientado para a avaliação de ligantes betuminosos modificados com polímeros. De facto, estes ligantes têm vindo a ser cada vez mais utilizados, mas ainda não se conhece bem a evolução das suas propriedades durante o envelhecimento. Um betume não modificado de penetração 35/50 (B1), um betume de penetração 70/100 modificado com EVA (PmB1), e um betume de penetração 70/100 modificado com PEAD (PmB2) foram envelhecidos aplicando dois procedimentos diferentes. Num dos procedimentos os ligantes foram expostos a 75-min no ensaio de RTFOT (envelhecimento do ligante). No outro método, os ligantes foram usados para a produzir amostras de mistura betuminosa, recuperando-se os ligantes envelhecidos (envelhecimento a curto prazo da mistura e recuperação do ligante) depois de realizados ensaios mecânicos. Para todos os ligantes, foram determinadas as propriedades reológicas de cada um dos seus estados: não envelhecido, envelhecido por RTFOT e recuperado após envelhecimento. Estes ensaios reológicos indicam obviamente um aumento na rigidez devido ao envelhecimento por RTFOT. No entanto, os resultados reológicos após recuperação apresentaram-se pouco coerentes. Daí, os ligantes PmB1 e PmB2 foram também sujeitas a ensaios de DSC de modo a tentar esclarecer estes resultados inesperados. A análise dos resultados de DSC indicou a ausência dos polímeros nos ligantes betuminosos modificados com polímero após o processo de recuperação. No entanto, a análise dos resultados FTIR demonstraram que as frações betuminosas recuperadas dos ligantes modificados foram efetivamente envelhecidas quimicamente quando as misturas foram produzidas e compactadas.
Fundação para a Ciência e a Tecnologia (FCT) - Project FCOMP 01 0124 FEDER 020335 (PTDC/ECM/119179/2010).
FEDER funds through the Operational Competitiveness Program COMPETE

碩士
高苑科技大學
土木工程研究所
96
Taiwan is located in the subtropical area. Because the weather conditions of much rain and high temperature the face of road is easy to worn out and full of cracks. In addition, the busy transportation makes the rut even worse. In order to reduce the damage of road surface, adding high polymer in the asphalt to change its guality is a must. Thus the asphaltic perceptive to warmth and strength can be increased. And the performance of shop front can be improved as well. For finding better guality of asphalt, this reserch is designed to compare the physical property, mechanics nature and rheology behavior before and after adding. At last a highly safisfied high polymer material-MPE is selected. Further more, we probe into the nature under its different content. And its better content is evaluated. Nature experiments respectively include physical property test, mechanics nature test, rheology appearace test and emanation test. Its physical characteristics are presented by means of needle malleability, proportion, and viscid degree; mechanics mechanism by toughness test and rheology behavior by dynamic shear rheometer(DSR). Finally emanation test is used to measure the stability of heat it stores. The experiment concludes adding high polymer material contributes to strengthen the asphalt basis and improving the perceptive to warmth. And the ideal content of MPE to better asphalt quality is between 8% and 10%.

Dissertação de mestrado integrado em Engenharia Civil
The national regulations have been replaced by European regulations in the several countries of the European Community. This progressive uniformisation of European standards require the national companies to submit their products to standardised tests validated in Europe, but enables the development of improved products to meet the demand of new markets, thus expanding business trade. In this context, Portuguese companies can diversify their portfolio and invest in products aimed at colder regions, which in general are more prosperous. However, these regions have a climate different from the national reality, with colder and longer winters, in which our companies have little experience. When temperatures drop to significantly low levels, pavements are subjected to thermal stress and can present several distresses, such as thermal cracking. In these situations, polymers can be used as modifiers in asphalt binders to improve their properties, such as elastic recovery, cohesion and ductility. Polymers also minimize some of the problems of asphalt mixtures, such as thermal and fatigue cracking and permanent deformation. The objective of this work was to study the behaviour of asphalt mixtures at low temperatures, in particular when using modified bitumens. Thus, three binders were selected and tested in this study: a standard 50/70 penetration grade bitumen, and two polymer-modified binders (PMB) obtained adding 2.5% and 5.0% of SBS, respectively, to the 50/70 pen grade bitumen. Then, the PMBs were incorporated into SMA 11 mixtures, which were subjected to low-temperature mechanical tests based on the European Standard EN 12697-46. The materials and methods used in this work were applied to support the definition of the best future alternatives for cold climates. Some of the properties of the asphalt binders and mixtures evaluated in this work were the thermal cracking resistance, creep, elastic recovery, cohesive strength and ductility strength. Overall, it is concluded that the asphalt mixtures produced and evaluated in this work performed adequately at low temperatures, in particular those with PMB. The knowledge regarding laboratory tests at low-temperatures (EN 12697-46) and their derived conclusions will help to develop new pavement solutions for those colder climate zones.
Os regulamentos nacionais têm sido substituídos por regulamentos europeus nos vários países da comunidade europeia. Esta progressiva uniformização das normas europeias exige que as empresas nacionais submetam os seus produtos a ensaios padronizados na Europa, mas permite melhorar os produtos para responder à procura de novos mercados, expandindo o comércio das empresas. Neste contexto, as empresas portuguesas podem diversificar o seu portfólio e investir em produtos destinados a regiões mais frias, que em geral são mais prósperas. No entanto, estas regiões têm um clima muito diferente da realidade nacional, com invernos mais frios e longos, para o qual há pouca experiência. Quando as temperaturas descem para níveis muito baixos, os pavimentos são submetidos a tensão térmica e podem apresentar várias degradações, como fendilhamento térmico. Nestes casos, podem ser usados polímeros para modificar o betume e melhorar algumas das suas propriedades, como a recuperação elástica, coesão e ductilidade. Os polímeros também reduz alguns dos problemas das misturas betuminosas, como o fendillhamento térmico e por fadiga e a deformação permanente. O objetivo deste trabalho foi estudar o comportamento das misturas betuminosas a baixas temperaturas, em particular quando se utilizam betumes modificados. Assim, foram selecionados e ensaiados três ligantes neste estudo: um betume convencional com penetração 50/70 e dois betumes modificados com polímeros (PMB) obtidos pela adição de 2,5% e 5,0% de SBS, respetivamente, ao betume 50/70. Em seguida, os PMB foram então incorporados em misturas do tipo SMA 11, que foram submetidas a ensaios mecânicos a baixas temperaturas com base na norma europeia EN 12697-46. Os materiais e os métodos utilizados serviram para se definir quais as melhores alternativas futuras para climas frios. Algumas das propriedades dos ligantes e das misturas betuminosas que foram avaliadas foram a resistência ao fendilhamento térmico, fluência, recuperação elástica, força coesiva e ductilidade. Em geral, concluiu-se que as misturas betuminosas avaliadas neste trabalho tiveram um desempenho adequado a baixas temperaturas, em particular as produzidas com PMB. O conhecimento dos ensaios de laboratório a baixas temperaturas (EN 12697-46) e suas conclusões inerentes ajudarão a desenvolver novas soluções de pavimentação para as zonas climáticas mais frias.