| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 8.55 MB | Adobe PDF |
Authors
Abstract(s)
A sociedade enfrenta atualmente vários constrangimentos como consequência do agravamento dos fenómenos climáticos extremos, manifestados na escassez de água e nas precipitações intensas. Adicionalmente, a crescente ocupação urbana tem incrementado a impermeabilização dos solos, levando ao aumento do escoamento superficial e, consequentemente, à diminuição da infiltração, tornando as cidades mais vulneráveis às inundações. De modo a conceber práticas de resiliência adequadas e responder às atuais exigências de sustentabilidade têm sido procuradas soluções no âmbito dos Sistemas de Drenagem Urbana Sustentável, destacando-se a utilização de pavimentos permeáveis. A sua aplicação, sobretudo em zonas com baixo volume de tráfego, permite reduzir o escoamento superficial, retardando e diminuindo a probabilidade de ocorrência de picos de cheia. Apesar do conhecimento científico e técnico acerca dos pavimentos permeáveis, persistem lacunas ao nível do desempenho funcional, hidrológico e mecânico em situações de aplicação real, aspetos versados no presente trabalho.
O trabalho de investigação tem por objetivo o estudo de um pavimento betuminoso permeável desde a formulação otimizada das misturas betuminosas até à monitorização em fase de serviço. O desenvolvimento da composição das misturas betuminosas drenantes permitiu o melhoramento da sua durabilidade e desempenho com a utilização de fibras celulósicas revestidas com betume, definidas como um material sustentável, com uma percentagem máxima a incorporar na mistura de 0,5 % que possibilita a retenção do ligante. Esta solução, juntamente com a utilização de um betume modificado com polímeros, confere às misturas maior aderência entre o ligante e os agregados, proporcionando, simultaneamente, a porosidade requerida (> 16 %). A dupla camada betuminosa drenante utilizada em camada de desgaste forneceu benefícios hidrológicos substanciais com capacidade de infiltração total para intensidades de precipitação de 100, 200 e 300 mm/h. A capacidade de infiltração diminuiu em 12 % após simulação de condições de colmatação, a qual foi recuperada com uma manutenção simples. Os resultados obtidos evidenciam que as misturas betuminosas drenantes desenvolvidas em laboratório desempenham de forma eficiente o seu papel como meio de infiltração do escoamento superficial.
Em campo, a avaliação do pavimento foi realizada através da execução de troços experimentais. A monitorização destes incrementou o conhecimento acerca do desempenho do pavimento betuminoso permeável com um sistema de infiltração parcial, particularmente quando aplicado em áreas de estacionamento. Este garantiu, desde o início da construção, uma capacidade de infiltração (2x10-3 m/s) acima do valor mínimo exigido na normalização europeia (0,027x10-3 m/s), verificando-se uma diminuição progressiva ao longo do tempo resultante da colmatação. A manutenção simples da superfície do pavimento revelou-se um processo importante na durabilidade e restabelecimento da função do pavimento permeável. A análise à qualidade da água infiltrada permitiu constatar que o pavimento apresenta elevado potencial de reutilização para rega, resultado da retenção de metais pesados, cumprindo os requisitos presentes no Decreto-Lei n.º 236/98. O sistema de pavimento betuminoso permeável proposto neste estudo apresentou resultados promissores que motivam a sua aplicação não só em estacionamentos, como em estradas urbanas, permitindo a adaptação e mitigação às alterações climáticas e à urbanização densificada.
Society faces currently several constraints as a result of the extreme weather conditions worsening, manifested in water scarcity and intense rainfall. Additionally, the growing urban occupation has increased the soils sealing, leading to an increase in surface runoff and, consequently, to a decrease in water infiltration, turning cities more vulnerable to flooding. In order to conceive appropriate resilience practices and respond to current sustainability requirements, solutions have been sought within the Sustainable Urban Drainage Systems framework, given emphasis to the use of permeable pavements. Its application, mainly in areas with low traffic volume, allows the reduction of the surface runoff, delaying and decreasing the probability of flood peaks occurrence. In spite of the scientific and technical knowledge about permeable pavements, gaps persist in terms of functional, hydrological and mechanical performance in real application situations, aspects mentioned in the present work. The research work aims to study a permeable asphalt pavement from the asphalt mixtures optimized mix design to the monitoring in service phase. The porous asphalt composition development allowed the improvement of its durability and performance with the cellulosic fibres use coated with bitumen, defined as a sustainable material, with a maximum percentage to be incorporated in the mixture of 0.5 % that allows the binder retention. This solution, together with the use of a bitumen modified with polymers, gives the mixtures greater adherence between the binder and the aggregates, providing at the same time the required porosity (> 16 %). The double layer porous asphalt used in the surface layer provided substantial hydrological benefits with full infiltration capacity for rainfall intensities of 100, 200 and 300 mm/h. The infiltration capacity decreased by 12 % after clogging conditions simulation, which was recovered with a simple maintenance. The results obtained show that the porous asphalt developed in the laboratory efficiently performs its role as a means of surface runoff infiltration. In the field, the pavement assessment was carried out through the execution of experimental sections. The monitoring of these, increased knowledge about the permeable asphalt pavement performance with a partial infiltration system, particularly when applied in parking areas. This has assured, since the construction start, an infiltration capacity (2x10-3 m/s) above the minimum value required in European standardization (0.027x10-3 m/s), with a progressive decrease over time that was a result of clogging. The pavement surface simple maintenance proved to be an important process in the durability and restoration of the permeable pavement function. The infiltrated water quality analysis allowed to verify that the pavement presented a high potential for reuse in irrigation, resulting from the retention of heavy metals, accomplishing the requirements presented in the Portuguese Law-Decree No. 236/98. The permeable asphalt pavement system proposed in this study showed promising results that motivate its application not only in parking lots, but also on urban roads, allowing the adaptation and mitigation to climate change and urban densification.
Society faces currently several constraints as a result of the extreme weather conditions worsening, manifested in water scarcity and intense rainfall. Additionally, the growing urban occupation has increased the soils sealing, leading to an increase in surface runoff and, consequently, to a decrease in water infiltration, turning cities more vulnerable to flooding. In order to conceive appropriate resilience practices and respond to current sustainability requirements, solutions have been sought within the Sustainable Urban Drainage Systems framework, given emphasis to the use of permeable pavements. Its application, mainly in areas with low traffic volume, allows the reduction of the surface runoff, delaying and decreasing the probability of flood peaks occurrence. In spite of the scientific and technical knowledge about permeable pavements, gaps persist in terms of functional, hydrological and mechanical performance in real application situations, aspects mentioned in the present work. The research work aims to study a permeable asphalt pavement from the asphalt mixtures optimized mix design to the monitoring in service phase. The porous asphalt composition development allowed the improvement of its durability and performance with the cellulosic fibres use coated with bitumen, defined as a sustainable material, with a maximum percentage to be incorporated in the mixture of 0.5 % that allows the binder retention. This solution, together with the use of a bitumen modified with polymers, gives the mixtures greater adherence between the binder and the aggregates, providing at the same time the required porosity (> 16 %). The double layer porous asphalt used in the surface layer provided substantial hydrological benefits with full infiltration capacity for rainfall intensities of 100, 200 and 300 mm/h. The infiltration capacity decreased by 12 % after clogging conditions simulation, which was recovered with a simple maintenance. The results obtained show that the porous asphalt developed in the laboratory efficiently performs its role as a means of surface runoff infiltration. In the field, the pavement assessment was carried out through the execution of experimental sections. The monitoring of these, increased knowledge about the permeable asphalt pavement performance with a partial infiltration system, particularly when applied in parking areas. This has assured, since the construction start, an infiltration capacity (2x10-3 m/s) above the minimum value required in European standardization (0.027x10-3 m/s), with a progressive decrease over time that was a result of clogging. The pavement surface simple maintenance proved to be an important process in the durability and restoration of the permeable pavement function. The infiltrated water quality analysis allowed to verify that the pavement presented a high potential for reuse in irrigation, resulting from the retention of heavy metals, accomplishing the requirements presented in the Portuguese Law-Decree No. 236/98. The permeable asphalt pavement system proposed in this study showed promising results that motivate its application not only in parking lots, but also on urban roads, allowing the adaptation and mitigation to climate change and urban densification.
Description
Keywords
Mistura Betuminosa Drenante Dupla Camada Pavimento Permeável Colmatação Capacidade de Infiltração Qualidade da água