Publicações

The ballast mechanical behavior is one of most important aspects governing the performance and safety conditionsof railway track lines. Usually comprised of natural crushed rock, the research for alternative ballastmaterials becomes interesting both environmentally and economically. This paper presents a comparison betweenaggregates of steel slag and granite by means of monotonic and cyclic triaxial tests carried out on scaleddown ballast specimens. The monotonic triaxial tests were conducted at three different confining pressures tofailure and to critical state. The long-term cyclic tests (at least 106 cycles) were conducted in two stress pathscompatible with heavy haul loadings. The results showed that the steel slag aggregate has higher values ofstrength parameters compared to the granite aggregate and better long-term deformability behavior, expressedby lower degradation and particle breakage and a faster tendency for stabilization the permanent deformation.

The ballast railway layer is one of the main applications of crushed rocks in civil engineering. Environmentalconcerns have influenced the use of by-products and recycled materials as alternatives to the exploitation of new quarries. One of the main industrial by-products available near railways is steel furnace slag. Mechanical tests performed by monotonic and cyclic triaxial loading showed that this material can perform better than a granite aggregate traditionally used in the ballast layer. The work presented in this paper intends to be a contribution explaining the influence of the individual particles

Railway infrastructure managers run dedicated inspection vehicles to monitor the geometric quality of the track (among other aspects) to detect irregularities and ensure safe running conditions of railway lines, in accordance with specific regulations. Unfortunately, these inspections disturb the normal traffic operation, especially in networks with intense traffic; are generally carried out only a few times per year; and, consequently, do not provide prompt identification of critical situations. Considering the recent developments and cost reduction in sensing capabilities of smartphones, the authors present an approach to use these technologies to perform constant acceleration measurements inside in-service trains to complement the assessment of the structural performance and geometrical degradation of the tracks. Cross-correlation values above 0.85 were obtained between the standard deviations of the longitudinal level and the experimental vertical accelerations measured on-board a passenger train on an 11-km railway stretch. ,e results showed that the approach can be used to identify critical situations that affect the performance of the track, regarding passenger comfort, degradation rates, and risk of derailment. It may comprise a low-cost and crowdsourced complement to the general current practice of track geometric inspection by dedicated vehicles and contribute to an earlier detection of track malfunctions, consequently, to a more efficient maintenance planning and infrastructure management.

The selection and use of technical parameters and performance indicators plays an essential role in thepavement management process. It is known that if more parameters are used, a more accurate evaluationof pavement condition is achieved, improving the choice of maintenance and rehabilitation interventions.However, one of the most expensive activities of the pavement management process is data collection.Accordingly, it is necessary to find a balance between the data collected and the real needs of the process.This paper presents a new approach for the development of pavement condition indicators using a machinelearning algorithm named regularised regression with lasso. The present discussion is supported by a casestudy, which compares the proposed method with current practice for the description of the condition of aPortuguese motorway. The results suggest that the application of machine learning methods can improvethe accuracy of pavement condition indicators when less data are available, contributing to achieve abalance between the needed data and information obtained.

Transition zones to bridges and other structures are critical locations in railway tracks that frequently evidencepoor long-term performance. Under sleeper pads (USPs) are reported to reduce ballast degradation and controlthe vertical stiffness of the track, which suggests that USPs can contribute to mitigating the frequent negativeeffects associated with transitions zones. Aiming at understanding in greater depth the influence of USPs on thedynamic behaviour of transition zones and at improving the design of such railway structures, the authors havedeveloped an extensive experimental and numerical study. 3-D FEM models using state-of-the-art numericalapproaches were successfully calibrated and validated using experimental measurements. Simulations supportedprevious findings, highlighting the potential benefit of USPs and pointing to the need to careful designing of theresilient properties of USPs and their arrangement along transition zones, so as to avoid introducing abruptvariations in track vertical stiffness.

Ballast aggregate is a natural material widely used in railway lines. Its mechanical properties and particle geometry are meticulously defined using well-established standards and characterisation procedures. Though extensively validated, these procedures have some limitations: they are operator dependent; only provide major particle dimensions; do not inform on surface colour; nor allow for advanced particle wear analysis or particle-based simulations. This work presents a cost-efficient photogrammetry method for 3D reconstruction of ballast particles, as an alternative to the significantly expensive laser scanning. It produces digital models of equivalent or higher quality, allowing for advanced and automated particle geometry analyses. Particle meshes produced here are shared among researchers.

The railway track system is a crucial infrastructure for the transportation of people and goods in modern societies. With the increase in railway traffic, the availability of the track for monitoring and maintenance purposes is becoming significantly reduced. Therefore, continuous non-destructive monitoring tools for track diagnoses take on even greater importance. In this context, Ground Penetrating Radar (GPR) technique results yield valuable information on track condition, mainly in the identification of the degradation of its physical and mechanical characteristics caused by subsurface malfunctions. Nevertheless, the application of GPR to assess the ballast condition is a challenging task because the material electromagnetic properties are sensitive to both the ballast grading and water content. This work presents a novel approach, fast and practical for surveying and analysing long sections of transport infrastructure, based mainly on expedite frequency domain analysis of the GPR signal. Examples are presented with the identification of track events, ballast interventions and potential locations of malfunctions. The approach, developed to identify changes in the track infrastructure, allows for a user-friendly visualisation of the track condition, even for GPR non-professionals such as railways engineers, and may further be used to correlate with track geometric parameters. It aims to automatically detect sudden variations in the GPR signals, obtained with successive surveys over long stretches of railway lines, thus providing valuable information in asset management activities of infrastructure managers.

The authors present a numerical study on railway track subgrade reinforcement using short soil-binder columns through injection, below the ballast layer. A 3D FEM program developed in MATLAB that considers the dynamic train

Sudden changes in the structural and geotechnical properties of railway tracks along its course are normally associated with subgrade stiffness transitions, differential settlements and, ultimately, hanging sleepers that reduce the performance of the railway system. This paper aims at analysing and quantifying the impact of such situations, particularly cut-fill transitions combined with the presence of culverts, on the train-track system response. A cut-fill transition on a buried culvert is used as case study for which track geometry and stiffness evaluation data were available. A numerical model, considering the coupled train-track interaction, was developed using a 3D FEM dynamic analysis tool that was further improved here with a mixed implicit-explicit time integration scheme. The results suggest that the faster degradation rates typically found at similar locations are mostly related to the development of early permanent deformations in the subgrade layers, rather than to sudden stiffness transitions, which then aggravate the problem by causing important dynamic amplifications in the train-track interaction. Therefore, numerical approaches similar to the one presented herein can be valuable tools for designers and railway infrastructure managers in order to anticipate and mitigate such negative effects at these locations.

Soil improvement with hydraulic binders is currently used in practice because of the advantages of using the local soil enhancing its geotechnical properties. However, environmental issues related to quicklime applications and carbon-dioxide emissions associated to Portland cement production encouraged the development of new binders. In this work, alkaline-activated cement (AAC) synthetized by fly ash and an alkaline solution was used to stabilize silty sand. The behavior of the treated soil was evaluated performing tests on a physical model and the results were compared to laboratory data to define its compaction, strength, and stiffness properties. Those tests include nuclear density gauge measurements, light falling weight deflectometer tests, and plate load tests, whereas unconfined compression tests with unload

São apresentados resultados de ensaios triaxiais monotônicos e cíclicos conduzidos em corpos de prova de 150 mm de diâmetro por 300 mm de altura, em escala reduzida numa proporção de 1:2,5 em relação à granulometria de lastro padrão AREMA nº 24. Analisou-se um agregado de escória de aciaria quimicamente inerte comparativamente a um agregado de granito, relativamente à resistência e à deformabilidade. Os ensaios cíclicos foram conduzidos em dois escalões de carga de 500.000 ciclos, sendo cada escalão compatível com o carregamento imposto por vias do tipo heavy haul (32,5 toneladas/eixo e 40 toneladas/eixo). Os resultados mostraram que o agregado de escória de aciaria apresentou parâmetros de resistência superiores comparativamente ao agregado de granito e um melhor comportamento quanto à deformabilidade, expresso por maiores valores de módulo de resiliência, menores índices de quebra e degradação de partículas e uma maior tendência de estabilização das deformações permanentes, fenômeno conhecido como shakedown.

In the transport infrastructures context, the support layershave a fundamental role in the degradation of the track condition,both in structural aspects and in terms of fouling of the materialsthat comprise them. Particularly in the field of railway research,ballast is the key element, and its fouling leads to trackdeterioration. Thus, the main focus of this work is based on theevaluation of the ballast fouling using Ground Penetrating Radar(GPR). In order to determine the applicability of the method on theevaluation of railway characteristics, laboratory samples andmeasurements carried out in situ, on sections of two railways inoperation were analysed. In both cases the different ballast foulinglevels were evaluated, using specialized software for this approach(temporal analysis); and then comparing these results with resultsof a frequency analysis in an automatic calculation program. Thispaper presents the possibilities of testing with GPR equipment byanalysing an electromagnetic wave, in the temporal and frequencydomain for the purpose of investigating the level of degradation ofa railway track. Some recommendations are also made regardingthe use of this method, adding the need for future developments inan attempt to reduce the number of destructive tests still practicednowadays.

The top granular layers of railway tracks, including ballast and sub-ballast, are essentially resilient structures, where the deformation imposed by one passing train is mostly recovered elastically, with only a very small part being permanent non-recoverable deformation. These residual deformations however accumulate over the hundreds of thousands of axle

Este artigo discute o comportamento mecânico do lastro ferroviário de escória de aciaria de forno de arcoelétrico, com base em resultados de ensaios triaxiais monotônicos, os quais foram obtidos no âmbito de uma investigação mais abrangente, que tem como objetivo avaliar o potencial de aplicação destas escórias, na forma de agregados britados, em lastro de vias-férreas. Nesta primeira fase, os objetivos foram avaliar a capacidade de este material proporcionar estabilidade mecânica à via-férrea, bem como situar os valores limites de tensão a aplicar em ensaios triaxiais de carga cíclica, relativamente à tensão deviatórica de rutura, a serem realizados numa etapa posterior. Nos ensaios até agora realizados foram utilizadas amostras de lastro em escala reduzida, obtidas pela técnica de decalagem por graduação paralela da curva de distribuição granulométrica de lastro padrão AREMA n. 24. Os resultados, obtidos em provetes de 150 mm de diâmetro por 300 mm de altura, sugerem tratar-se de um material com boas características mecânicas, expressas, nomeadamente, por elevados valores do módulo de deformabilidade, E, do ângulo de resistência ao cisalhamento, Øp, e do parâmetro de estado crítico, M.

A utilização de materiais alternativos, nomeadamente subprodutos industriais e materiais reciclados, na construção de infraestruturas de transporte e de obras geotécnicas, tem vindo a ser promovida por todo o mundo. Para garantir que a aplicação desses materiais é feita de forma eficiente, cumprindo os requisitos técnicos e ambientais das obras onde são utilizados, têm sido realizados diversos estudos e desenvolvidas especificações técnicas. No entanto, atendendo a que, na maioria das situações, as aplicações de alguns destes materiais são relativamente recentes, existe ainda pouca informação relativa ao desempenho a longo prazo das infraestruturas onde foram utilizados, nomeadamente no que se relaciona com o respetivo comportamento estrutural. Neste trabalho apresentam-se alguns resultados relativos à caracterização doagregado siderúrgico inerte para construção (ASIC), processado a partir das escórias de aciaria de fornode arco elétrico da Siderurgia Nacional, e à evolução das características de superfície e do comportamentoestrutural de um trecho experimental construído em 2007 num troço de estrada em Portugal, no qual foiutilizado ASIC em aterro e em diversas camadas do pavimento. A inspeção visual, os resultados dos ensaiosmecânicos realizados e o valor dos assentamentos medidos em marcas superficiais, no âmbito de umacampanha de monitorização levada a cabo em 2017, cerca de dez anos após a entrada em serviço doreferido trecho, permitem concluir que o pavimento existente na zona onde se aplicou ASIC como materialde construção encontra-se, em geral, em melhor estado e exibe um melhor comportamento estrutural,quando se compara com as zonas adjacentes que foram construídas com materiais naturais. Em termos deassentamentos máximos do aterro, não se observaram diferenças significativas quando se compararam aszonas com ASIC com as zonas adjacentes.

A degradação das vias-férreas é um aspeto intrínseco do seu comportamento. Para proceder à reabilitaçãoestrutural da via, de forma a garantir o nível de desempenho exigido, por vezes recorre-se a técnicas demelhoramento do solo da respetiva subestrutura. O objetivo deste estudo é avaliar o comportamentoestrutural da via-férrea quando a subestrutura é reforçada com colunas de solo-ligante. Nesse sentido,foram desenvolvidos modelos numéricos tridimensionais por diferenças finitas, que permitiram realizarestudos paramétricos relativos à influência do diâmetro e disposição das colunas e da posição de carga, naresposta estrutural da via-férrea. Para além disso, foram considerados para a camada de balastro doismodelos diferentes de comportamento do material e, no final, comparados os resultados dessas análises.Os resultados dos estudos mostraram que, ao implementar colunas de solo-ligante, as tensões verticaissão direcionadas para as colunas, sendo evidente o encaminhamento das cargas. Em geral, isso resulta naredução da tensão vertical nas camadas superiores da subestrutura, de acordo com o que se pretende coma aplicação desta técnica de reforço. Em termos de deslocamentos verticais (deflexões), a consideração docomportamento elástico linear da camada de balastro conduziu a resultados semelhantes aos obtidos nomodelo elástico não linear. No entanto, em termos de tensões verticais, os resultados da abordagem nãolinear evidenciaram menores concentrações de tensões nas colunas, quando comparado com o queacontece na abordagem elástica linear. Este comportamento poderá estar relacionado com o facto de omódulo de Young atribuído à camada de balastro na abordagem linear ter sido ligeiramente sobrestimado,o que sugere a necessidade de trabalhos futuros em termos de calibração daquele parâmetro.

Track stiffness and track deflection measurements are fundamental to understand the track behaviour and the causes that lead to its underperformance, and ultimately its failure (Berggren, 2009; Puzavac et al., 2012). Although in recent years several techniques and methods have emerged to evaluate and quantify the track support modulus, most of them are difficult to implement (Kerr, 2000) and only perform well at limited speeds, around 60 km/h (INNOTRACK, 2008). Therefore, such procedures may cause disruptions and disturbances in the normal traffic and involve high costs for the railway managers (Berggren et al., 2014). Most of these techniques require the deduction of the axle loads during train passage - a procedure that may lead to divergent interpretations. A recent work by Le Pen et al. (2016) proposes a new method that analyses the measurements in the frequency domain and does not require the measurement of the axle loads of the trains. Because the number of reported applications of this method is still very limited, though some promising results have already been obtained, it is important to keep improving its understanding. Therefore, to obtain more insight into the limitations and strengths of this approach, the authors have applied the abovementioned method to a set of track measurements obtained in earlier experimental works. This work focuses on the conclusions drawn during the application of the method to transition zones in railway tracks. In previous studies, this method seems to have only been applied to railway tracks on low stiffness soils and at sites without abrupt differences in vertical stiffness. The novelty of this study lies on its application to a wide range of track support conditions, including Under Sleeper Pads (thus different vertical stiffness levels), and different types of trains such as high-speed services, regular passenger trains and freight trains.

Due to the necessity to transport each time more a bigger material amount, especially commodities, in the last years, the railways have developed cost effective strategies to increase capacity based on the axle loading increase. This, constitute a challenge for managers as the track can be saturated or even technically unsuitable for the unforeseen efforts that the components will be subjected provoking damage and causing track deterioration. As a result of traffic accumulation, railway components are affected by induced stresses provoking degradation of geometry over time. This, occurs either through partial geometry loss or through the development of specific damage to the component. To reduce the degradation impact, different maintenance methods are used. Tamping is a common procedure to restore geometry while grinding is used to partially eliminate rail roughness. The different maintenance types are performed according to different strategies. In the active approach, maintenance is executed according to pre-determined values for accumulated transported materials, while in the reactive strategy, a value for a structural or geometric parameter is used to determine when maintenance should be performed. Therefore, problems related to the degradation of railways subjected to high loads (larger than 22.5 tons/axle), entail a specific case. These loads attain values of approximately 40 tons/axle, as in the case of railways used for transporting commodities. In a heavy haul scenario, the higher load values lead to extra forces on the track elements that may cause excessive damage, hence causing faster eneral track deterioration. The preview of the evolution of the track structural and geometric parameters over time including the maintenances can provide basis for an analysis regarding its costs, being this, of paramount importance in an analysis concerning a certain implementation (e.g. load increase).

The reinforcement of railway track foundations, through injection of binders, without theneed of removal of track components (i.e. rails, sleepers and ballast) has many advantages compared totraditional approaches, which normally are more complex, costly and strongly affect train operations. Tocontribute to a deeper understanding of issues associated with soil-binder column reinforcements, numericalstudies were developed to analyse and compare different column layouts and to assess the effect ofsuch reinforcements on the dynamic train-track interaction. To that aim, two three-dimensional numericalprograms were used. Aspects of the train-track interaction and values of stresses and displacementson the track and trackbed layers are analysed and discussed. The results suggest that in similar problemsof track platforms with uneven track stiffness, it is important to take into account the non-linear elasticbehaviour of the ballast to obtain a more accurate three-dimensional load distribution.

Nowadays, there is a strong pressure to use industrial byproducts and recycled materials in civil engineering works. In Portugal, for example, several studies have been carried out with the aim of demonstrating that some industrial byproducts exhibit good mechanical properties and can be used instead of natural materials, providing technical and economic advantages without environmental and public health risks (Fortunato and Pardo de Santayana, 2007). One of these materials is the

This case study refers to the first significant experience with asphalt rubber, manufactured by the wetprocess, applied on a full scale rehabilitation project in Portugal. It concerns the application of a gapgradedasphalt rubber wearing course in the rehabilitation of the pavement of National road stretchesEN 104 between Azurara and Trofa and EN 105 between Travagem and Santo Tirso. / O presente caso de estudo refere-se à primeira experiência relevante, em Portugal, na qual seutilizaram misturas com betume modificado com borracha reciclada de pneus na reabilitação deestradas nacionais. Diz respeito, em particular, à aplicação de misturas betuminosas rugosas combetume modificado com borracha em camadas de desgaste, no âmbito da reabilitação do pavimento deum troço da estrada nacional EN 104, entre Azurara e Trofa, e da estrada nacional EN 105, entreTravagem e Santo Tirso.

This case study refers to a successful application of an asphalt rubber wearing course in the frame ofthe rehabilitation of the pavement of the National Road EN 14 between

This case study refers to plant hot mix recycling works in the frame of the rehabilitation of a stretch ofthe motorway A1, located in the centre of Portugal.It concerns the use of 20% - 25% of Reclaimed Asphalt in the production of two different asphaltconcrete mixtures for application in binder courses. / O presente caso de estudo refere-se ao fabrico e aplicação de misturas betuminosas recicladas a quenteem central, num troço da auto-estrada A1 localizado no centro do País. Neste caso, foram utilizadas nofabrico de duas misturas diferentes, uma Mistura Betuminosa Densa e um Betão BetuminosoSubjacente à Camada Drenante, respectivamente, cerca de 20 % e 25 % de misturas betuminosasrecuperadas.

This case study refers to the first known application of RAP in the production of hot mix asphaltconcrete in Portugal. It concerns the application of a plant hot mix recycled asphalt concrete as abinder course in a national road stretch located in the North of Portugal. / O presente caso de estudo refere-se à primeira obra realizada em Portugal, na qual se procedeu àreutilização de materiais betuminosos fresados na reabilitação de um pavimento flexível de um trechode uma estrada nacional (EN105), situada no Norte do País. Os materiais fresados foram reciclados emcentral mediante a incorporação de novos materiais, e posteriormente utilizados em camadas deregularização.

This case study refers to an application of cold in situ recycling of an old asphalt pavement usingbitumen emulsion.The rehabilitation works were performed in 2 phases: The first phase consisted in recycling theexisting asphalt and granular layers up to 120 mm deep and application of a slurry surfacing. Thesecond phase consisted in placing an asphalt cold mix binder course and a new slurry surfacing. / O presente caso de estudo refere-se à aplicação de misturas betuminosas recicladas a frio

This case study refers to a successful application of cold in situ recycling of asphalt layers from aheavily cracked pavement using bitumen emulsion.A new hot mix asphalt binder course and a new wearing course were placed on the recycled layer. / O presente caso de estudo refere-se a uma aplicação bem sucedida de reciclagem a frio

The use of alternative materials, in particular industrial by-products and waste materials, in the construction oftransport infrastructures and geotechnical works, has been promoted across the world. Nonetheless, considering that, in most situations, the application of some of these materials is fairly recent, little information is available on the long-term performance of the infrastructures in which they were used. This work mentions some characteristics of the Inert Steel Aggregate for Construction (ISAC). It presents some results related to the evolution in the surface characteristics and the structural behaviour of a field trial built on a road section in Portugal. ISAC was used in the embankments and pavement layers. The visual inspection, the results of the mechanical tests performed, and the values of the settlements measured on the surface markings about ten years after the section is open to traffic led to conclude that the pavement in the zone where ISAC was used as a construction material is, in general, in a better condition and presents better structural performance than the adjacent areas built with natural materials. The embankment's maximum settlements in the areas with ISAC were similar to the ones observed in the adjacent areas.

Railway tracks may be perceived as simple physical structures, but in fact they entail a significant level of complexity as refers to the assessment and prediction of their transient and long-term behaviors. These mostly result from the intrinsic characteristics of their components and of the dynamic interaction with the suc-cessive passing trains at different speeds and with different loading characteris-tics. The railway industry

A via férrea balastrada é uma estrutura relativamente simples, mas exibe um comportamento complexo, nomeadamente devido às distintas solicitações dinâmicas a que está sujeita, e à forma como se comportam e interagem os seus diversos elementos. O método dos elementos finitos é particularmente adequado à análise do funcionamento destas estruturas, possibilitando a modelação das ações e a utilização de modelos constitutivos avançados para os diversos materiais que constituem o sistema, permitindo considerar a variação das características físicas e geométricas no espaço. Neste capítulo descreve-se e demonstra-se a aplicação de uma ferramenta de modelação numérica tridimensional, concebida especificamente para o cálculo da resposta dinâmica da via-férrea, cujo desenvolvimento, ao longo dos últimos anos, tem tido a contribuição dos autores. Para além da apresentação e validação da ferramenta de modelação, são apresentados estudos relativos à análise do comportamento da via em situações particulares.

A utilização de machine learning tem despertado a curiosidade e o interesse do meio académico e empresarial. Com efeito, a aplicação de machine learning, baseada em técnicas capazes de aprender com os dados, tem sido efetuada com sucesso em diversos contextos. Este sucesso é particularmente evidente nas áreas que utilizam grandes volumes de dados e que procuram obter informação que permita alimentar modelos de previsão.Na área dos Transportes, para além da resolução de questões relacionadas com a mobilidade, é expectável que a aplicação de técnicas de machine learning venha a ser cada vez mais frequente em questões relacionadas com a gestão de infraestruturas, em particular no estabelecimento de modelos de previsão do comportamento.Neste capítulo procura-se evidenciar o potencial da aplicação de machine learning em sistemas de gestão de pavimentos, através da descrição de alguns dos trabalhos desenvolvidos pelos autores neste domínio, essencialmente relacionados com a aplicação de machine learning no desenvolvimento de modelos de previsão do desempenho dos pavimentos, uma das temáticas essenciais dos sistemas de gestão de pavimentos.

Este artigo apresenta uma etapa de uma pesquisa mais abrangente que está em andamento na Universidade do Porto, no âmbito do grupo de pesquisa Construct-Geo, que visa avaliar os aspectos geomecânicos de materiais alternativos para uso como camada de lastro em vias férreas do tipo heavy haul. São apresentados resultados de ensaios triaxiais monotônicos e cíclicos conduzidos em corpos de prova de 150 mm de diâmetro por 300 mm de altura, em escala reduzida numa proporção de 1:2,5 em relação à granulometriade lastro padrão AREMA N. 24. Analisou-se um agregado de escória de aciaria, quimicamente e ambientalmente, inerte comparativamente a um agregado de granito, relativamente à resistência e à deformabilidade. Os ensaios cíclicos foram conduzidos em dois escalões de carga de 500.000 ciclos, sendo cada escalão compatível com o carregamento imposto por vias do tipo heavy haul com, respectivamente,32,5 toneladas/eixo e 40 toneladas/eixo. Os resultados mostraram que o lastro de escória de aciaria apresentou parâmetros de resistência superiores comparativamente ao lastro de granito e um melhor comportamento quanto à deformabilidade, expresso por maiores valores de módulo de resiliência, menoresíndices de quebra e degradação de partículas e uma maior tendência de estabilização das deformações plásticas, fenômeno conhecido como shakedown e que também foi investigado.

The reuse of recycled materials in geotechnical works has awakened a growing interest in the last few years in Portugal. A committee (GT-VROG) within the Portuguese Geotechnical Society (SPG) was created recently for analysing the current state of this kind of use and for promoting it nationwide. As part of the activities of the group, a national survey within producers of waste materials and potential users in geotechnical works was carried out, and a national seminar was organised within the framework of the activities of the TC-3 of the ISSMGE, in order to discuss the present situation in the country and the best ways to develop the reuse of this kind of materials in geotechnical applications. The seminar had the participation of representatives of the different entities interested on the subject (producers, users, administration and research centres), as well as of invited foreign specialists from other European countries. Taking advantage of the results of these activities, the current state of the use of recycled materials in geotechnical works in Portugal is briefly presented and analysed next.

Transportation infrastructures are vital to our society. These infrastructures naturally tend to deteriorate over time. A set of activities is then required to manage existing assets in accordance with sound management principles. These activities are usually integrated into systems that manage infrastructures according to technical, social and economic aspects. This research aims to examine the potential of applying machine learning techniques to current transportation infrastructure management systems. Machine learning is an application of artificial intelligence enabling systems to automatically learn and improve from experience (data), arriving at solutions not explicitly programmed. Powered by algorithms that can learn from data, machine learning leads to efficient and effective systems that improve over time. Over the last few years, the application of machine learning has transformed several industries and could do so for transportation infrastructure as well.To achieve the research objectives, a set of studies was performed. Each of these studies had a specific objective, the set of which can be expressed as follows: to define combined performance indicators for pavement condition assessment using machine learning; to develop machine learning models for pavement performance prediction; to formulate machine learning solutions to overcome pavement data issues, such as missing data; to integrate machine learning techniques into decision support systems for pavement maintenance management. Together these studies explored the development of machine learning applications for solving some standard pavement management problems, providing insights into the application of machine learning to transportation infrastructure management systems. The studies successfully demonstrated the potential of machine learning applications for pavement management systems. It showed that machine learning is applicable to various transportation asset management problems, such as condition assessment, performance prediction, and decision support, and that it is able to outperform some of the analytical techniques currently used. Overall, this research work finds that machine learning is a promising tool for transportation infrastructure management systems.

The railway track continually degrades over its life cycle. This has negative consequences for maintenance and availability of the lines and is particularly evident at locations with abrupt changes in the track

Esta dissertação pretende ser um contributo para o desenvolvimento de uma metodologia de abordagem do problema da renovação de plataformas ferroviárias em serviço, em particular no que se refere à avaliação da capacidade de carga e técnicas de reforço. A referida metodologia foi desenvolvida com o objectivo de apoiar os projectos de renovação das vias férreas.Os principais aspectos abordados são os mecanismos que contribuem para a degradação das vias férreas, a caracterização

Nas últimas décadas tem vindo a verificar-se, em Portugal bem como no resto do mundo, umacentuado crescimento do volume de tráfego rodoviário e das cargas transportadas pelos veículospesados. Tem-se observado, igualmente, um aumento das exigências funcionais, relacionadas com asegurança e conforto do utente das infra-estruturas, a par das preocupações de carácter ambiental, oque conduz à necessidade de pavimentos rodoviários cada vez mais resistentes e duráveis.Consequentemente, tem-se vindo a recorrer a soluções de pavimentação que envolvem maioresespessuras de camadas betuminosas o que implica uma maior parcela de contribuição docomportamento deste tipo de materiais no desempenho das estruturas de pavimentos. Daqui decorre,entre outros aspectos, uma crescente preocupação com a deformação permanente deste tipo demateriais. Esta situação é também sentida em diversos países, nomeadamente nos países europeus,no Canadá e nos Estados Unidos da América.O presente trabalho tem como objectivo contribuir para um melhor conhecimento do comportamentoà deformação permanente de misturas betuminosas aplicadas em camadas de desgaste depavimentos rodoviários, possibilitando o estabelecimento de metodologias e de critérios de avaliação,que conduzam à selecção de materiais adequados às exigências actuais. Como principais aspectosabordados referem-se a caracterização do comportamento viscoelástico destes materiais, através daexecução e interpretação de ensaios laboratoriais com aplicação de cargas repetidas, que simulemas condições observadas in situ, e a modelação do comportamento à deformação permanente dasmisturas.É analisado o fenómeno da deformação permanente, bem como a sua forma de manifestação naestrutura do pavimento

The main objective of the COST Action 354

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As crescentes exigências impostas ao transporte ferroviário e a necessidade de o tornar num sistemade transporte mais competitivo, têm levado ao desenvolvimento de novas soluções de via-férrea.Estas novas soluções constituem inovações tecnológicas de via-férrea que diferem da via balastradatradicional na utilização de diferentes materiais e métodos construtivos. Apostam fortemente naredução da necessidade de conservação e renovação da via, o que se traduz na diminuição doscustos associados à sua operação, assim como no aumento da disponibilidade da linha.Assim, estas soluções apresentam uma melhor resposta a velocidades de circulação cada vez maiselevadas e a maiores volumes de tráfego, que tendem a conduzir a maior deterioração da via e aconsequentes maiores custos de conservação e renovação. Em comparação com a via tradicional,estas soluções podem ser mais vantajosas, no que se refere à segurança, a aspectos ambientais, àgestão da operação e a custos globais, quando se considera o ciclo de vida da infra-estrutura.Embora estas tecnologias tenham vindo a ser testadas e aplicadas em alguns países, desde há váriasdécadas, em particular no Japão, só mais recentemente diversos países demonstraram especialinteresse pela sua aplicação. Face a estas vantagens, tem-se verificado actualmente uma crescentetendência para a adopção destas novas soluções, sobretudo para as linhas de alta velocidade,particularmente na Europa e Ásia Oriental.Dentro deste contexto, e tendo em conta a previsível integração de Portugal na Rede Europeia de AltaVelocidade, desenvolveu-se o presente estudo com o objectivo de apresentar diversas soluções devia-férrea que estão disponíveis e compará-las com a solução tradicional de via balastrada.O estudo incide na descrição de concepções de via-férrea não tradicionais, como a via sem balastro ea via de apoio misto, fazendo-se especial referência às principais vantagens e desvantagens da viasem balastro, face à solução tradicional de via balastrada, e à experiência da sua aplicação.Apresenta-se ainda uma síntese da situação actual da aplicação destas novas soluções em paísesque apostaram fortemente nas redes de alta velocidade.Do estudo desenvolvido conclui-se que, para novas linhas de alta velocidade, estas soluções podemser bastante atractivas, como alternativa à via balastrada tradicional.Os autores agradecem a todas as entidades e pessoas a título individual a autorização expressa paraa publicação das ilustrações apresentadas neste estudo, encontrando-se estas devidamentereferenciadas.

The reuse of recycled materials in geotechnical works has awakened a growing interest in the last few years in Portugal. A committee (GT-VROG) within the Portuguese Geotechnical Society (SPG) was created recently for analysing the current state of this kind of use and for promoting it nationwide. As part of the activities of the group, a national survey within producers of waste materials and potential users in geotechnical works was carried out, and a national seminar was organised within the framework of the activities of the TC-3 of theISSMGE, in order to discuss the present situation in the country and the best ways to develop the reuse of this kind of materials in geotechnical applications. The seminar had the participation of representatives of the different entities interested on the subject (producers, users, administration and research centres), as well as of invited foreign specialists from other European countries. Taking advantage of the results of these activities, the current state of the use of recycled materials in geotechnical works in Portugal is presented and analysed next.

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