Tese de Doutoramento em Engenharia Civil - Vias de Comunicação ; O Brasil é um país que possui o sistema de transporte terrestre apoiado essencialmente em rodovias. A idade avançada dos pavimentos rodoviários brasileiros e o eminente crescimento do tráfego e da acção das cargas de roda cada vez mais intensas, têm levado os pavimentos flexíveis a um acelerado processo de deterioração no qual o uso de técnicas d...
A restauração de pavimentos flexíveis trincados através da execução de uma camada de reforço ou da fresagem parcial do revestimento existente e a colocação de uma camada asfáltica convencional são soluções frequentemente adotadas pelos órgãos rodoviários brasileiros. No entanto, tal prática tem mostrado que nem sempre o objetivo proposto é alcançado, uma vez que a camada executada não atinge a vida de projeto p...
A observação do desempenho de pavimentos em serviço tem demonstrado que a utilização de misturas asfálticas com asfalto-borracha em camadas de revestimentos apresentam um comportamento estrutural superior quanto à fadiga e à deformação permanente comparativamente às misturas convencionais. Considerando a crescente aplicação deste tipo de misturas asfálticas no Brasil, neste trabalho foram realizados, em laborat...
Permanent deformation or rutting, one of the most important distresses inflexible pavements, has long been a problem in asphalt mixtures. Throughout the years, researchers have used different test methods lo estimate the performance of asphalt mixtures in relation to rutting. One of the alternatives to reduce permanent deformation in asphalt pavement layers is through the use of mixtures produced with asphalt r...
Asphalt rubber mixtures are one of the most promising techniques to extend the service of asphalt pavement overlays. Asphalt rubber binder is composed of crumb rubber from reclaimed tires and conventional asphalt. The asphalt rubber binder can be obtained through wet process in two different systems: tire rubber-modified asphalt binder (produced at industrial plants and continuous blending (produced in asphalt ...
Fatigue resistance is used in the analysis and design of pavements to predict their life cycle. It is evaluated through time consuming laboratory tests, mainly when performed at very low strain levels. At low strain levels the testing time can last more than one day. Due to the heterogeneity of the material, a large number of samples are tested during days or weeks. The results of fatigue tests are expressed in...
The fatigue resistance of asphalt mixtures is calculated through laboratory tests which require some time depending on the strain level applied to the specimen. For very low strain levels, identical to the one installed in the pavement of this study, one test may last more than one week depending on the testing frequency. The time needed for the development of the fatigue law may last longer. The number of spec...
Pavement layers are characterized by basic material properties, among which the stiffness modulus and the Poisson ratio assume a preponderant importance in linear elastic anal-ysis. The stiffness modulus is usually assessed through samples extracted from a pavement or prepared in laboratory. The number of specimens used to calculate the stiffness modulus of an asphalt mixture plays an important role in the prec...
The fatigue performance of asphalt mixtures is used to predict pavement life to control the cracking in the asphalt layers. The design of an asphalt pavement is usually made for a specific temperature, what is intended to represent the pavement behaviour throughout a whole year. For damage analysis during a year, along which the pavement temperature constant-ly varies, it is necessary to calculate the fatigue p...
The majority of Brazilian roadpavements consistsof thin pavement structures unable to resist the damage caused by heavy loads and an increasing traffic demand. The main structural distress modes found in Brazilians asphalt layers is fatigue cracking. One of the prom-ising techniques to improve the pavement performance is through asphalt rubber mixtures, which make use of crumb rubber from scrap tires to modify ...
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