Avaliação do comportamento de misturas betuminosas do tipo stone mastic asphalt, incorporando fibras celulosicas revestidas com cera poliolefinica
Miniatura indisponível
Data
2020
Autores
Título da revista
ISSN da revista
Título do Volume
Editora
Resumo
Nos últimos anos tem-se verificado uma crescente aplicação de misturas betuminosas
do tipo Stone Mastic Asphalt (SMA), como uma alternativa às soluções convencionais. Esta
aposta deve-se ao facto destas misturas proporcionarem ao pavimento uma maior durabilidade
e um menor custo no ciclo de vida. As misturas do tipo SMA são constituídas por agregado de
granulometria descontínua, composta por um esqueleto de agregado britado grosso e por um
mastique betuminoso rico em betume. Devido ao seu relativamente elevado conteúdo de
ligante, e por forma a evitar o seu escorrimento, são usualmente utilizados aditivos
estabilizadores. Em Portugal, os aditivos estabilizadores são, em geral, granulados de fibras de
celulose revestidas com betume, embora noutros países sejam utilizados outros tipos de aditivos
estabilizadores.
Com o objetivo de responder ao interesse/necessidade da utilização de fibras celulósicas
revestidas com cera poliolefínica, no presente trabalho avalia-se o comportamento e
desempenho das misturas betuminosas do tipo SMA contendo este tipo de fibras
comparativamente a misturas betuminosas do tipo SMA incorporando fibras de celulose
revestidas com betume. Para tal, este estudo teve por base uma empreitada de beneficiação com
a aplicação, em camada de desgaste, das misturas betuminosas do tipo SMA com incorporação
dos dois tipos de fibras celulósicas, permitindo o acompanhamento das várias etapas da obra,
bem como o estudo comparativo entre as misturas através de ensaios realizados no âmbito do
controlo de qualidade do pavimento e em campanha laboratorial.
A realização do presente trabalho permitiu concluir que, independentemente, do tipo de
revestimento das fibras celulósicas incorporadas nas misturas, os procedimentos construtivos
são idênticos, bem como são semelhantes os resultados das diversas propriedades avaliadas.
Assim, este trabalho contribuiu para a possibilidade de inclusão das fibras celulósicas revestidas
com cera poliolefínica em Caderno de Encargos, como alternativa à utilização de fibras
celulósicas revestidas com betume.
Palavras-chave: Mistura betuminosa; Stone Mastic Asphalt (SMA); fibras
celulósicas revestidas com betume; fibras celulósicas revestidas com cera poliolefínica;
formulação; desempenho; durabilidade.
In the last years there has been an increasing application of Stone Mastic Asphalt (SMA) type bituminous mixtures as an alternative to conventional solutions. This is committed with the fact that these mixtures provide the pavement with greater durability and a lower life cycle cost. These mixtures are made of aggregates with discontinuous granulometry, composed by a coarse aggregate skeleton filled with a bituminous mastic rich in bitumen. Due to its relatively high binder content and in order to avoid its draining, stabilizers are usually used. In Portugal, stabilizers incorporated in SMA mixtures are, in general, cellulose fibers coated with bitumen, although other types of stabilizers are used in other countries. In order to respond to the interest and need for the use of cellulose fibers coated with polyolefin waxes, this dissertation assesses the behavior and performance of SMA containing those fibers, in comparison with SMA incorporating cellulose fibers coated with bitumen. This study was based on a processing contract with the application, in a wearing course, of SMA incorporating the two types of cellulose fibers under consideration, allowing the monitoring of the various stages of the work, as well as the comparative study between the mixtures through tests performed in the framework of the pavement quality control and in a laboratory campaign. This study made possible to ascertain that, regardless of the type of coating of the cellulosic fibers incorporated in the SMA blends, the construction procedures are identical as well as the results of the various properties assessed. Thus, this work has contributed to the possibility of including polyolefin wax-coated cellulose fibers in the specifications as an alternative to the use of bitumen-coated cellulose fibers. Keywords: Bituminous mixture; Stone Mastic Asphalt (SMA); cellulose fibers coated with bitumen; cellulose fibers coated with polyolefin wax; mix design; performance; durability.
In the last years there has been an increasing application of Stone Mastic Asphalt (SMA) type bituminous mixtures as an alternative to conventional solutions. This is committed with the fact that these mixtures provide the pavement with greater durability and a lower life cycle cost. These mixtures are made of aggregates with discontinuous granulometry, composed by a coarse aggregate skeleton filled with a bituminous mastic rich in bitumen. Due to its relatively high binder content and in order to avoid its draining, stabilizers are usually used. In Portugal, stabilizers incorporated in SMA mixtures are, in general, cellulose fibers coated with bitumen, although other types of stabilizers are used in other countries. In order to respond to the interest and need for the use of cellulose fibers coated with polyolefin waxes, this dissertation assesses the behavior and performance of SMA containing those fibers, in comparison with SMA incorporating cellulose fibers coated with bitumen. This study was based on a processing contract with the application, in a wearing course, of SMA incorporating the two types of cellulose fibers under consideration, allowing the monitoring of the various stages of the work, as well as the comparative study between the mixtures through tests performed in the framework of the pavement quality control and in a laboratory campaign. This study made possible to ascertain that, regardless of the type of coating of the cellulosic fibers incorporated in the SMA blends, the construction procedures are identical as well as the results of the various properties assessed. Thus, this work has contributed to the possibility of including polyolefin wax-coated cellulose fibers in the specifications as an alternative to the use of bitumen-coated cellulose fibers. Keywords: Bituminous mixture; Stone Mastic Asphalt (SMA); cellulose fibers coated with bitumen; cellulose fibers coated with polyolefin wax; mix design; performance; durability.
Descrição
Orientação: Elói João Faria Figueiredo ; co-orientação: Luís Manuel Trindade Quaresma
Palavras-chave
MESTRADO EM ENGENHARIA CIVIL, ENGENHARIA CIVIL, CONSTRUÇÃO CIVIL, DURABILIDADE DE ESTRUTURAS, MISTURAS BETUMINOSAS, CIVIL ENGINEERING, CONSTRUCTION, STRUCTURAL DURABILITY, ASPHALT MIX