Publicação
Influence of the modification of asphalt mixtures on their behaviour at low temperatures
| Resumo: | The national regulations have been replaced by European regulations in the several countries of the European Community.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. |
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| Autores principais: | Dias, Ana Paula Rocha da Costa |
| Assunto: | Baixas temperaturas Betume modificado com polímeros (PMB) Estireno-butadieno-estireno (SBS) Stone mastic asphalt (SMA) Norma europeia Desempenho das misturas betuminosas Low-temperature Polymer modified binder (PMB) Styrene-butadiene-styrene (SBS) European standard Asphalt mixture performance |
| Ano: | 2020 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | 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. |
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