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Abstract(s)
As problemáticas ambientais que se têm levantado nos últimos anos conduzem a um maior
cuidado com o meio ambiente. Para colmatar este facto surgiram, na indústria viária, as
misturas betuminosas com betumes temperados que se encontram dentro de um conjunto de
novas técnicas que estão a ser desenvolvidas para redução dos consumos, nomeadamente, a
poupança de energia e a emissão de gases para a atmosfera, através da diminuição da
temperatura de produção.
O principal objetivo desta dissertação é estudar o comportamento mecânico de misturas
betuminosas produzidas com betumes temperados, com e sem incorporação de material
fresado, ao nível da resistência à fadiga. Nestas misturas as temperaturas de produção são
inferiores às das misturas betuminosas tradicionais a quente.
Esta dissertação inicia com um estado de arte, onde se abordam misturas betuminosas a
quente, misturas betuminosas com betumes temperados e misturas com incorporação de
material fresado (RAP – Reclaimed Asphalt Pavement), bem como os benefícios a nível social,
ambiental e económico. Em seguida, faz-se uma breve abordagem à caracterização da
resistência à fadiga de misturas betuminosas, expondo os ensaios mais utilizados.
Posteriormente, apresenta-se a metodologia usada para a produção, em laboratório, das
misturas betuminosas com diferentes teores de betume para a determinação do teor ótimo de
ligante, através da realização de ensaios para a obtenção das propriedades fundamentais. Por
último, são realizados ensaios de caracterização, nomeadamente, o ensaio de tração indireta
em compressão diametral, o ensaio de sensibilidade à água e o ensaio de flexão em quatro
pontos para avaliação da resistência à fadiga das misturas betuminosas. No final, apresentamse
as principais conclusões do estudo e propõem-se alguns trabalhos futuros no
desenvolvimento deste.
Os resultados obtidos mostram que as misturas betuminosas com betumes temperados, com
ou sem incorporação de material fresado, apresentam um comportamento mecânico à fadiga
muito idêntico às misturas betuminosas a quente. Concluiu-se que as misturas betuminosas
temperadas têm um desempenho similar às misturas tradicionais a quente, embora careçam
de um cuidado acrescido na fase de produção e aplicação, nomeadamente, no controlo da
temperatura de compactação.
The environmental issues that have been raised over recent years have led to greater concern with the environment. To address this fact the asphalt industry has developed warm mixasphalt in the context of new technologies that are being developed to reduce energy consumption, in particular saving energy and decreasing gas emissions into the atmosphere, by lowering the mixing temperature. The aim of this dissertation is to study the mechanical behaviour of warm-mix asphalt, with and without incorporation of reclaimed asphalt pavement, at the level of fatigue resistance. In these mixtures, the mixing temperatures are lower than those of the traditional hot-mix asphalt. This dissertation begins with a state of art which addresses hot-mix asphalt, warm-mix asphalt and mixtures with incorporation of reclaimed asphalt pavement, as well as the associated social, environmental and economic benefits. Then, the fatigue resistance of asphalt mixtures is characterised, addressing the most used tests. Subsequently, the methodology used for mixing, in the laboratory, asphalt mixtures with different levels of bitumen content to determine the optimum binder content is presented, by conducting tests in order to obtain fundamental properties. Finally, characterisation tests are performed, namely the indirect tensile stiffness modulus test, the water sensitivity test, and the four point bending test in order to evaluate the fatigue resistance of the asphalt mixtures. In the end, the main conclusions of the study are presented and further research is suggested. The obtained results show that the mechanical fatigue behaviour of warm-mix asphalt, with or without addition of reclaimed asphalt pavement, is very similar to hot-mix asphalt. It was concluded that warm-mix asphalt have a similar performance to traditional hot-mix asphalt, although they require extra care in mixing and placing, in particular, with regard to the control of the compaction temperature.
The environmental issues that have been raised over recent years have led to greater concern with the environment. To address this fact the asphalt industry has developed warm mixasphalt in the context of new technologies that are being developed to reduce energy consumption, in particular saving energy and decreasing gas emissions into the atmosphere, by lowering the mixing temperature. The aim of this dissertation is to study the mechanical behaviour of warm-mix asphalt, with and without incorporation of reclaimed asphalt pavement, at the level of fatigue resistance. In these mixtures, the mixing temperatures are lower than those of the traditional hot-mix asphalt. This dissertation begins with a state of art which addresses hot-mix asphalt, warm-mix asphalt and mixtures with incorporation of reclaimed asphalt pavement, as well as the associated social, environmental and economic benefits. Then, the fatigue resistance of asphalt mixtures is characterised, addressing the most used tests. Subsequently, the methodology used for mixing, in the laboratory, asphalt mixtures with different levels of bitumen content to determine the optimum binder content is presented, by conducting tests in order to obtain fundamental properties. Finally, characterisation tests are performed, namely the indirect tensile stiffness modulus test, the water sensitivity test, and the four point bending test in order to evaluate the fatigue resistance of the asphalt mixtures. In the end, the main conclusions of the study are presented and further research is suggested. The obtained results show that the mechanical fatigue behaviour of warm-mix asphalt, with or without addition of reclaimed asphalt pavement, is very similar to hot-mix asphalt. It was concluded that warm-mix asphalt have a similar performance to traditional hot-mix asphalt, although they require extra care in mixing and placing, in particular, with regard to the control of the compaction temperature.
Description
Keywords
Betume Temperado Material Fresado Misturas Betuminosas Resistência à Fadiga