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Asphalt binders play a key role in the resistance of the asphalt mixture to failure by rutting, fatigue cracking and low-temperature cracking. With respect to rutting, the multiple stress creep and recovery (MSCR) test has been taken by researchers worldwide as an interesting alternative to estimate the susceptibility of the material to the accumulation of permanent strain (Jnr – nonrecoverable creep compliance) and the level of its elastic response (R – percent recovery), as well as its stress sensitivity and degree of nonlinearity (Jnr, diff – percent difference in nonrecoverable compliances). In addition to these parameters, the four-element Burgers model has been commonly used in the literature to fit the repeated creep data obtained in this test. The present study utilized the MSCR test to analyze the creeprecovery behavior of asphalt binders modified with polyphosphoric acid (AC+PPA, PG 76-xx) and Elvaloy® terpolymer combined with PPA (AC+Elvaloy+PPA, PG 76-xx) at high pavement temperatures ranging from 52 to 76°C. A recent test protocol standardized by AASHTO (T350-14) was followed in the experiments, and rheological modeling of the data was made based on a seven-step procedure previously described elsewhere. Substantial increases in R and considerable decreases in Jnr are observed in the binder after the addition of PPA or a combination of Elvaloy® terpolymer and PPA, which can be translated into higher elastic responses (R values) and a much lower rutting potential in the field (Jnr values). This is especially remarkable for the AC+Elvaloy+PPA, which showed the best outcomes in the MSCR test, a high level of elasticity at the aforementioned pavement temperatures and a fairly low stress sensitivity. On the other hand, the parameter GV (viscous component of the creep stiffness) obtained from the Burgers model ranked the AC+PPA as the most rut resistant formulation at temperatures no greater than 58°C. Despite the fact that the results of the AC+PPA in the MSCR test are not as promising as the ones of the AC+Elvaloy+PPA, this formulation may be taken as an option to replace the base material on roads and highways with higher traffic levels and/or lower vehicle speeds, provided that the pavement temperatures are not higher than 64°C.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES ANP/Petrobrás Transport on highways, mainly on asphalt pavement, is crucial for many countries around the globe, being relevant to the economic and social contexts of a country. Another key factor is the mechanical behaviour of asphalt mixtures, result of the materials used, traffic and weather corrosion, amongst other conditions, and is directly linked to its on-field performance, being expressed, by the mechanical properties acquired, through scientific in lab studies. It is of the highest priority the knowledge of the behaviour of the mixtures used for the sizing and specification of the pavement layers, for them to be used properly on State-run roads. It is considered that permanent deformation phenomenon is a key effect found in asphaltic pavements. In this way, this research aims to evaluate asphaltic mixtures utilized on the field, with different aggregates and asphalt binders, as well as several grain size ranges recommended by the road agencies that oversee the state highways (DAER and DNIT), seeking to understand how its characteristics act on resisting the permanent deformation phenomenon. Furthermore, it presents relationships between the scales: binder; mixture and; track. To carry out the study, eight mixtures were collected and evaluated the mechanical behaviour of these mixtures through lab and field examination, focusing on permanent deformation, as defined on the study Flow Number, Hamburg Test and the binders by the Multiple Stress Creep Recover study. In addition, the stretches of road were monitored to evaluate permanent deformation of the layers. With the analysis of the results, it was possible to verify the modified binders by polymer and rubber demonstrated a satisfactory performance on permanent deformation when compared to conventional binders. The stiffness of asphaltic mixtures under high temperatures is a predictor of huge importance by the permanent deformation performance, on a relation of strength gain with respect to rutting, as of gain of stiffness. It was verified that the stiffness behaviour of asphaltic mixtures under high temperatures is directly related to the stiffness of the asphaltic binders, on field, suggesting the performance against permanent deformation is strongly connected to the behaviour of the binder-scale. Der Verkehr auf Kraftfahrstraßen ist nicht nur für viele Länder weltweit von großer Bedeutung, sondern auch, hauptsächlich was Asphalttragschicht und Asphaltdecken angeht, für das Land im wirtschaftlichen und im sozialen Kontext relevant. Wichtige Punkte sind ebenso das mechanische Verhalten der Asphaltmischungen, das aus den Mischguten, den Verkehrs- und den Wetterauswirkungen entstehen, und die Leistung vor Ort, die eindeutig auf die mechanischen Eigenschaften bezogen und im wissenschatflichen Experimente im Labor zu erkennen sind. Für die Bemessung und für die Spezifikation der Asphaltschichten ist das Kenntnis des angewendeten Mischungsverhaltens auf den Kraftfahrstraßen des Bundesstaates von großer Wichtigkeit. Das Phänomen der fortdauernden Verformung liegt an einem Mangel des Asphaltbodens. In dieser Art und Weise bringt die hier dargestellte Forschung sowohl eine Evaluation der vor Ort analysierten Asphaltmischungen dar, die aus verschiedenen Asphaltaggregaten und Bindemitteln entstehen, als auch analysiert die von DAER und DNIT vorgeschlagenen Korngröße, um besser die Einwirkungen der Eigeschaften auf die Beständigkeit der konstanten und fortdauernden Verformung. Außerdem werden auch die Maßstaben Bindemittel, Mischung und Piste überprüft. Um diese Forschung durchzuführen, wurden acht Mischungen mechanischem Verhalten zufolge im Labor und vor Ort evaluiert, anhand vom Testparameter Flow Number, vom Hamburgo Test und von der Probe Multiple Stress Creep Recover. Die Strecken, wo die Asphaltmischungen angewendet waren, wurden kontrolliert, damit man eine bessere Perspektive der Verformung der Asphaltschichten bekommen konnte. Mit den Ergebnissen kann man feststellen, dass die von Polymer- und Gummibeschichtungen abgeänderten Bindemittel im Vergleich zu den konventionellen Bindemitteln eine zufriedenstellende Performance haben. Die Steifigkeit der Asphaltmischungen bei hohen Temperaturen übt einen großen Einfluss auf die Performance der fortdauernden Verformung aus, da so ein Leistungsgewinn zu erkennen ist, was die Absenkung angeht. Die Studie zeigt das Steifigkeitsverhalten der Mischungen in einem Kontext von hohen Temperaturen, der damit verbunden ist, dass die Bindemittel auch zu steifig sind. Das weist darauf hin, dass die Performance und die Leistung vor der fortdauernden Verformung mit den Bindemitteln stark verknüpft sind. O transporte em rodovias, principalmente em pavimentos asfálticos, é crucial para muitos países ao redor do mundo, assim como possui alta relevância no contexto econômico e social do País. Outro fator chave que se destaca é o comportamento mecânico destas misturas asfálticas que procede dos materiais de constituição, das ações do tráfego e do clima, entre outras condições, e está, diretamente, atrelado à performance em campo, a ser expressa pelas propriedades mecânicas adquiridas, normalmente, por meio de ensaios em laboratório. É de extrema importância para o dimensionamento e especificação das camadas dos pavimentos, o conhecimento do comportamento das misturas utilizadas, de maneira efetiva, em rodovias do Estado. Considera-se que o fenômeno da deformação permanente é um dos principais defeitos encontrados nos revestimentos asfálticos. Desta maneira, esta pesquisa propõe avaliar misturas asfálticas aplicadas em campo, com diferentes agregados e ligantes asfálticos, além de diversas faixas granulométricas recomendadas pelos órgãos rodoviários que administram as rodovias no Estado (DAER e DNIT), buscando compreender de que maneira suas distintas características influenciam frente à resistência à deformação permanente. Além disso, apresentam-se relações entre as escalas: ligante; mistura e; pista. Para realização do estudo foram coletadas oito misturas, sendo avaliadas frente ao comportamento mecânico por meio de ensaios laboratoriais e de campo, com foco na deformação permanente, no parâmetro do ensaio Flow Number, Hamburgo Test e os ligantes pelo ensaio Multiple Stress Creep Recover. Também, os trechos de aplicação das misturas asfálticas foram monitorados a fim de avaliar a deformação permanente das camadas de revestimento. Com os resultados foi possível verificar que os ligantes modificados por polímero e borracha apresentaram desempenho à deformação permanente mais satisfatórios quando comparados aos ligantes convencionais. A rigidez das misturas asfálticas em altas temperaturas é fator preditor de elevada importância no desempenho da deformação permanente, em uma relação de ganho de resistência frente ao afundamento, a partir do ganho de rigidez. Foi verificado que o comportamento de rigidez das misturas asfálticas em altas temperaturas está, intimamente, atrelado à rigidez dos ligantes asfálticos, sugerindo que o desempenho à deformação permanente, em campo, está fortemente vinculado ao comportamento da escala ligante.