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- Permeable pavements – green infrastructures as a flood mitigation measurePublication . Afonso, Márcia Isabel Lopes; Almeida, Marisa S. Dinis; Fael, Cristina Maria SenaPermeable asphalt pavements have been one of the solutions used to increase the permeability of road pavements given the growing urbanization and climate change. The high porosity and permeability of surface layers with PA (porous asphalt) mixtures allows the water infiltration and, consequently, reduces superficial runoff and contributes to the recharge of underground aquifers. However, the infiltration capacity may be impaired by clogged pores with sediments. The double layer porous asphalt (DLPA) was developed to mitigate this effect. This is a key issue in the pavements’ service life. Information on the clogging processes in these layers is not yet well characterized. The study was carried out using a rainfall simulator in order to generate design storm events with a known intensity and duration. The experimental methodology adopted took into account different phases of evaluation of the infiltration capacity with two clogging cycles (500 and 1000 g m-2). The DLPA infiltration capacity was evaluated in the different phases after different precipitation events (100, 200 and 300 mm h-1). The results showed that, in general, the double layer porous asphalt has the capacity to drain the water, even after clogging and with lower voids content. The infiltration capacity was partially restored when subjected to simple maintenance.
- Repensar os pavimentos urbanos face ao impacto das mudanças climáticasPublication . Fael, Cristina Maria Sena; Almeida, Marisa S. Dinis; Afonso, MárciaAs alterações climáticas, nomeadamente as mudanças dos padrões de precipitação, têm sofrido uma forte aceleração e a tendência é que se tornem mais frequentes e intensos acarretando riscos como inundações e secas. Fazem-se sentir ao nível da qualidade da água superficial e subterrânea, na biodiversidade e ecossistemas territoriais e dos solos para agricultura. Os pavimentos betuminosos permeáveis, pelas suas propriedades de elevada permeabilidade e porosidade, apresentam-se eficazes no que diz respeito à redução da taxa de escoamento superficial e ao aumento da infiltração da água para o solo.
- Characterization of the Skid Resistance and Mean Texture Depth in a Permeable Asphalt PavementPublication . Afonso, Márcia Isabel Lopes; Almeida, Marisa S. Dinis; Fael, Cristina Maria SenaRoad pavements need a deep characterization of the surface layer, with which the vehicles have direct contact and, therefore, must provide security to the users. The use of permeable asphalt pavements (PAP) with porous layers has provide obvious advantages in reducing runoff and the rainwater infiltration into the soil or for storage. However, the study of the interaction between the pavement surface layer and the tire rubber requires additional tests in terms of texture and friction, since they are important parameters for the design, construction, management, maintenance and roads safety. Considering the application of a PAP in a parking lot, the study objective was to characterize in the field the pavement surface in terms of mean texture depth (MTD) and skid resistance (Pendulum test value, PTV). The methods used were the volumetric technique by the patch test and the pendulum test, according to EN 13036-1 and EN 13036-4, respectively. The double layer porous asphalt (DLPA) at the surface is characterized by having a structure with high voids content that led to results of clearly rougher macrotexture and good skid resistance. The normalized limit values were met, however, a very strong correlation between MTD and PTV was not observed. A comparison was also made with porous surfaces of other studies and it was found that porous asphalt has a good behaviour at the start of construction which may tend to improve in the long term. From the study, it is concluded that the PAP presents good performance of the surface layer, providing road safety to users.
- Pavimentos Betuminosos PermeáveisPublication . Almeida, Marisa S. Dinis; Afonso, Márcia Isabel Lopes; Fael, Cristina Maria SenaAs alterações climáticas têm conduzido a padrões de precipitação mais elevados e frequentes, causando um aumento instantâneo das águas pluviais que acarretam riscos como inundações.
- Desempenho de misturas recicladas temperadasPublication . Almeida, Marisa S. Dinis; Afonso, Márcia Isabel Lopes; Duarte, MartaUm dos principais desafios que a sociedade enfrenta nos dias de hoje são as preocupações com o meio ambiente sendo um dos objetivos mais procurado a diminuição do consumo de combustíveis fósseis e das emissões para a atmosfera.
- Estudo do desempenho de misturas betuminosas com incorporação de fibras celulósicasPublication . Afonso, Márcia Isabel Lopes; Maia, Maria; Almeida, Marisa S. Dinis; Martinho, Fernando; Fael, Cristina Maria SenaAs administrações de estradas em todo o mundo têm tomado consciência da importância do estudo das misturas betuminosas a aplicar nas camadas superficiais dos pavimentos rodoviários, face à necessidade de aumentar a durabilidade e o desempenho mecânico e funcional dos pavimentos. O principal objetivo deste estudo é avaliar o comportamento de quatro tipos de misturas, duas misturas drenantes e duas misturas densas. Foi, ainda, avaliada a influência da incorporação de fibras celulósicas aditivadas, com vista a melhorar a adesividade entre os agregados e o ligante. As fibras, de dois tipos distintos, irão contribuir para evitar a perda de ligante por escorrência, aumentar a afinidade entre agregado e betume e aumentar a resistência à deformação permanente.
- Afinidade entre Agregado e BetumePublication . Almeida, Marisa S. Dinis; Maia, Maria; Martinho, FernandoAs administrações de estradas um pouco por todo o mundo têm tomado consciência da importância de alargar o ciclo de vida dos materiais constituintes das diferentes camadas dos pavimentos rodoviários. O principal objetivo é aumentar a durabilidade os pavimentos pois quanto maior a vida útil, menos recursos serão gastos na sua conservação e reabilitação.
- Fluxing as a new tool for bitumen rheological characterization and the use of time-concentration shift factor (a c )Publication . Zoorob, Salah E.; Mturi, Georges A.; Sangiorgi, Cesare; Almeida, Marisa S. Dinis; Habib, Noor ZainabThe concept of temperature shift factor (aT) as defined by Doolittle, relating the free volume of a vis-coelastic material at the current and reference states is briefly examined together with the resultantWilliam-Landel-Ferry equation. This paper highlights the fact that change in free volume arise not onlyfrom temperature variations but can also result from the absorption of solvents and thus a generalizedDoolittle relation may also be applied to a solvent concentration shift factor (ac). To validate this concept,a small scale laboratory investigation was carried out by blending 40/60 penetration grade bitumen withvarious proportions of one type of cooking oil and conducting dynamic shear rheometer frequencysweeps at a range of temperatures. By applying time-concentration superposition to each flux content,it was possible to shift horizontally (ac) each set of complex modulus data measured at each test temper-ature, so that all sets superimpose onto the master curve of the base bitumen at a preselected referencetemperature. A direct relationship between conventional time-temperature shift and the proposed time-concentration shift factors was thus demonstrated using a sample of penetration grade bitumen and onetype of vegetable oil. Further experimentation with other bitumen-flux combinations is necessary priorto recommending general adoption of the proposed tool.
- Hydraulic Conductivity of the Permeable Asphalt Pavement – Laboratory vs In Situ TestPublication . Afonso, Márcia Isabel Lopes; Santos, Tiago Silva; Fael, Cristina Maria Sena; Almeida, Marisa S.DinisPermeable asphalt pavements (PAP) are a key measure for mitigating the climate change effects in urban areas. Cities are becoming increasingly dense and have large areas of waterproofing due to the excessive construction of buildings and highways that prevent the rainwater drainage into the soil. Recently, the PAP study with a double layer porous asphalt (DLPA) has been an alternative to the use of a porous asphalt single layer (PA), with recognized advantages in increasing water infiltration and, consequently, in decreasing surface runoff. It was developed in field a PAP of small dimensions to assess its capacity to respond to floods. The purpose of this study is to evaluate the hydraulic conductivity (K) of the DLPA applied on the PAP, both in laboratory conditions and in field conditions, and verify the representativeness of the laboratory results in relation to the results obtained in situ. In laboratory terms, the LCS permeameter was used, which evaluates the vertical and horizontal hydraulic conductivity, both in specimens produced in the laboratory and in cores extracted in situ. In the field, the LCS permeameter and the falling head permeameter were used to measure the hydraulic conductivity and the relative hydraulic conductivity (HC), respectively. The laboratory tests were performed according to Standards EN 12697-19 and NLT 327 and the in situ tests according to Standards EN 12697-40 and NLT 327. It was verified that the specimens produced in the laboratory of the two porous layers showed values of K (vertical and horizontal) lower than those obtained in the field cores, both for the individual layers PA and for the DLPA. Thus, it was found that the study in controlled environment differs in terms of results. This divergence justified the need to perform a field study in order to perceive the actual performance of the PAP surface layer. This study was characterized by the values of K (m/s) and HC (s-1), from which it was not possible to obtain a relation. From this study it was concluded that the measuring methods of the hydraulic conductivity in the laboratory were close to the behaviour of the same in situ, however its evaluation under real conditions is always essential.
- Permeable asphalt pavement as a measure of urban green infrastructure in the extreme events mitigationPublication . Afonso, Márcia Isabel Lopes; Fael, Cristina Maria Sena; Almeida, Marisa S. DinisPopulation growth in cities has led to an increase in the infrastructures construction, including buildings and roadways. This aspect leads directly to the soils waterproofing. In turn, changes in precipitation patterns are developing into higher and more frequent intensities. Thus, these two conjugated aspects decrease the rainwater infiltration into soils and increase the volume of surface runoff. The practice of green and sustainable urban solutions has encouraged research in these areas. The porous asphalt pavement, as a green infrastructure, is part of practical solutions set to address urban challenges related to land use and adaptation to climate change. In this field, permeable pavements with porous asphalt mixtures (PA) have several advantages in terms of reducing the runoff generated by the floods. The porous structure of these pavements, compared to a conventional asphalt pavement, allows the rainwater infiltration in the subsoil, and consequently, the water quality improvement. This green infrastructure solution can be applied in cities, particularly in streets or parking lots to mitigate the floods effects. Over the years, the pores of these pavements can be filled by sediment, reducing their function in the rainwater infiltration. Thus, double layer porous asphalt (DLPA) was developed to mitigate the clogging effect and facilitate the water infiltration into the lower layers. This study intends to deepen the knowledge of the performance of DLPA when subjected to clogging. The experimental methodology consisted on four evaluation phases of the DLPA infiltration capacity submitted to three precipitation events (100, 200 and 300 mm/h) in each phase. The evaluation first phase determined the behavior after DLPA construction. In phases two and three, two 500 g/m2 clogging cycles were performed, totaling a 1000 g/m2 final simulation. Sand with gradation accented in fine particles was used as clogging material. In the last phase, the DLPA was subjected to simple sweeping and vacuuming maintenance. A precipitation simulator, type sprinkler, capable of simulating the real precipitation was developed for this purpose. The main conclusions show that the DLPA has the capacity to drain the water, even after two clogging cycles. The infiltration results of flows lead to an efficient performance of the DPLA in the surface runoff attenuation, since this was not observed in any of the evaluation phases, even at intensities of 200 and 300 mm/h, simulating intense precipitation events. The infiltration capacity under clogging conditions decreased about 7% on average in the three intensities relative to the initial performance that is after construction. However, this was restored when subjected to simple maintenance, recovering the DLPA hydraulic functionality. In summary, the study proved the efficacy of using a DLPA when it retains thicker surface sediments and limits the fine sediments entry to the remaining layers. At the same time, it is guaranteed the rainwater infiltration and the surface runoff reduction and is therefore a viable solution to put into practice in permeable pavements.