This thesis investigates the impact of precipitation on the UK motorway network, with the aim of determining how speed, flow and accidents are affected. Climate change impact assessments require detailed information regarding the impact of weather in the current (baseline) climate and so this thesis seeks to address gaps in knowledge of current precipitation impacts to better inform future climate impact assessments. This thesis demonstrates that whilst precipitation does impact on traffic speeds, there is no universal significant single factor relationship. Indeed, a key threshold is identified at 0 mm hr-1 – the fastest speeds occur when there is no precipitation and speeds immediately decrease at the onset of precipitation. More detailed findings indicate the impact can be detected in both speed and maximum flow across much of the network as well as a downward reduction in the overall speed – flow relationship. In addition to speed flow, the impact of precipitation on road traffic accidents was also investigated. Fifteen percent of accidents in the UK occur in wet weather. Precipitation related accidents are shown to have a prolonged impact on the road network and can continue to cause a decrease in traffic speed and flow for up to three hours afterwards. With increased instances of heavy precipitation predicted as a result of climate change, these findings highlight the subsequent impact on journey speeds, travel times, traffic flows and the associated economic costs.

The author of this thesis deals with the issues of real time traffic management in junction areas and bottleneck sections on mainline railways in the event of service disturbances. A systematic methodology is proposed for modelling and solving real time train rescheduling problems in junction areas and bottleneck sections, including train re-sequencing and train re-timing. A formal mathematical model, the Junction Rescheduling Model (JRM) is proposed, based on a Mixed Integer Programming (MIP) to minimise a Weighted Average Delay (WAD). An innovative algorithm based on Differential Evolution algorithm, named DE_JRM is proposed for solving real time train rescheduling problems formulated with JRM. The performance of the algorithm DE_JRM has been evaluated with a stochastic method based on Monte-Carlo simulation methodology. The evaluation results show a good performance for both flyover and flat junctions compared with First Come First Served (FCFS) and a conventional ARS strategy. The author also extends the proposed methodology, including JRM and the algorithm DE_JRM, to model and solve real time train rescheduling problems for bottleneck sections of railway networks. Finally, an integrated system architecture for the traffic management and train control is introduced for system implementation of the proposed methodology of train rescheduling in junction areas and bottleneck sections on mainline railways.

Fundamental differences exist in soil types formed under temperate and tropical climatic conditions. Consequently, their use for road pavement design will require different approaches and standards. The absence of a systematic approach in addressing tropical pavement design requirements and the use of temperate design standards for tropical countries has led to early failure of road pavements in Ghana and other tropical countries. However, few studies have been carried out on developing standards based on field studies to determine key design parameters to address challenges of tropical pavement design. The aim of this research is to evolve a rational approach using mechanistic-empirical principles to design pavements for tropical laterite soils. The main objectives were therefore to determine the key pavement design parameters for Ghana through empirical studies as well as carry out technical and economic analysis to establish optimum designs for the various climatic zones of Ghana.

O Brasil, sendo um país com dimensões continentais, necessita de uma infraestrutura rodoviária que proporcione deslocamentos com conforto e segurança aos seus usuários, bem como transporte eficiente de insumos. Somente através da adequada gerência de pavimentos é possível realizar medidas corretivas nos momentos apropriados, assegurando a manutenção de um nível satisfatório de serventia. Os modelos de previsão de desempenho são ferramentas imprescindíveis na gerência de pavimentos, já que permitem estimar o momento (ou volume de tráfego equivalente) do surgimento de defeitos e programar a realização de serviços de manutenção. A pesquisa relatada nesta dissertação está inserida no projeto Rede Temática do Asfalto, incentivado pela PETROBRAS, e teve por objetivo avaliar o desempenho de dois trechos da rodovia federal BR-290/RS, dando ênfase à análise da influência da variação do lençol freático na deflexão medida no topo deste pavimento. Dando continuidade a estudos anteriores, foram calibradas linhas de tendência propostas para a rodovia em monitoramento, através de levantamentos de deflexões, deformações permanentes, de defeitos superficiais e textura. Ademais, controlou-se a variação da profundidade do lençol freático, através da instalação de um medidor de nível de água no trecho I da BR-290/RS e analisou-se a dependência do módulo de resiliência do solo de subleito em função da umidade de compactação, com ciclos de umedecimento e secagem. Os resultados dos levantamentos demonstraram que os trechos monitorados da BR-290/RS continuam em degradação, com afundamentos nas trilhas de roda e irregularidade longitudinal bastante elevados, sugerindo que intervenções já deveriam ter sido feitas. De forma diferente, a aderência pneu-pavimento e as deflexões apresentam valores aceitáveis. Nos ensaios laboratoriais observou-se que os solos compactados no ramo seco, ou que sofreram ciclos de secagem, apresentaram valores mais elevados de módulo de resiliência do que aqueles compactados no ramo úmido, ou que sofreram ciclos de umedecimento. Os módulos de resiliência mostraram-se quase independentes do estado de tensões e os modelos k-θ apresentaram escassa significância. Por fim, a análise realizada com o software Everstress 5.0 indicou que a oscilação da umidade no subleito influencia nas deflexões do pavimento. Como esperado, quanto maior a umidade, maiores as deflexões. / Brazil, as a country with continental dimensions, needs a road infrastructure that provides comfort and safety to its users, as well as efficient transport of goods. Only through proper pavement management, rehabilitation measures may be taken at appropriate times, ensuring a satisfactory level of serviceability being maintained. Performance models are essential tools in the management of pavements since they allow estimating the time (or equivalent traffic volume) of appearance of distresses and scheduling maintenance services. The research reported in this dissertation is part of the Asphalt Thematic Network project, funded by PETROBRAS, and aimed to evaluate the performance of two sections of federal highway BR-290/RS, with emphasis on the analysis of the influence of the water table variation on deflections measured on the top of this pavement. Continuing previous studies, trend lines were calibrated for pavements under monitoring, through surveys of deflections, permanent deformations, surface distresses and texture. In addition, the variation of the water table depth was controlled by the installation of a water level meter on the section I of BR-290/RS, and the dependence of the resilience module of the subgrade soil was analyzed in function of the compaction water content, with wetting and drying cycles. The results of the surveys showed that the monitored sections of the BR-290/RS continue to deteriorate, with values of rutting and roughness quite high, suggesting that interventions should have already been done. Conversely, the tire-pavement friction and the deflections present acceptable values. In the laboratory tests, it was observed that the soils compacted in the dry branch of the compaction curve, or that underwent drying cycles, presented higher values of resilient modulus than those compacted in the wet branch, or that underwent cycles of wetting. The resilient modules were almost independent of the stress state and the k-θ models presented little significance. Finally, the analysis performed with the software Everstress 5.0 indicated that the oscillation of the humidity in the subgrade influences the deflections of the pavement. As expected, the higher the humidity, the greater the deflections.

Este trabalho contém relato e discussão sobre atividades e resultados obtidos durante uma tentativa para mostrar que pressiômetros e ensaios \"in situ\" podem ser úteis ao estudo de tensões e deformações de solos utilizados na construção de sub-base de pavimentos flexíveis. Verificaram-se condições para aceitar a hipótese: \"os módulos de elasticidade, estimados a partir de manuseio sobre dados obtidos através de levantamentos em campo com uso de pressiômetros PENCEL, poderão ser utilizados para estudo da relação entre tensões e deformações de solos granulares de sub-bases de pavimentos flexíveis\" - isso foi efetuado usando conceitos e estimativas de módulo de resiliência. Para isso, descreveram-se equipamentos e métodos de ensaio triaxiais com repetições de aplicações de cargas, para estimativa de módulos de resiliência, e, processos para levantamento de dados com o pressiômetro \"in situ\" nas sub-bases de pavimentos. Os dados usados foram obtidos nas rodovias BR 230 Rodovia Transamazônica e PB 055 Sapé a Guarabira, estado da Paraíba, Brasil. Estudos sobre a interseção de intervalos de confiança indicaram que, para o intervalo de tensões em sub-bases de pavimentos, as estimativas de módulos de elasticidade a partir de ensaios em campo com o uso de pressiômetros podem ser de mesma ordem de grandeza que os valores obtidos a partir de ensaios triaxiais em laboratório. / In this work it was described and discussed the actions and the results obtained in activities to show that pressuremeters and \"in situ\" test should be useful to study stress and strains of soils used on building flexible pavement sub-base. lt was verified some conditions to accept the hypothesis \"the elasticity modulus estimated from data obtained from PENCEL pressuremeter data field surveying should be used to study granular soils stress and strain in the flexible pavement sub-bases\" - this was done using the resilient modulus concepts and surveying. lt was also described methods and equipment applied to dynamic triaxial tests, and the process used to survey field data using the pressuremeter to estimate the resilient modulus. The data was obtained in sub-bases from the BR 230 The Transzamazonic Highway and PB 055 The Sape to Guarabira Highway, located in the State of Paraiba, Brazil. lt was showed that the confidence intervals intersections among the elasticity modulus obtained from pressuremeter data field surveying and laboratory triaxial tests should have the same level of values.

Soil stabilisation is one of the most common techniques used to mitigate the undesirable properties of soft soils such as low compressive strength and high compressibility. Cement is the most commonly used binder for soil improvement applications in the UK and worldwide due to its high strength performance. However, its manufacture is energy intensive and expensive, contributing approximately 7% of global carbon dioxide (CO2) emissions. Therefore, the search for alternative raw materials, such as waste and by-products, is becoming critical in order to develop cost effective and more environmentally friendly binders to replace cement and reduce its negative environmental impact. Blended waste material fly ashes have been identified as promising alternatives to traditional binders (cement CEM-I) in different construction industries including ground improvement. The reuse of waste material fly ashes such as waste paper sludge ash (WPSA), palm oil fuel ash (POFA) and rice husk ash (RHA) has many advantages, specifically in terms of eliminating the cost of their transportation and eventual landfill, their continuous supply and the negligible, or zero, cost of production. This research project details the process of the development of a new cementitious binder, produced by blending cement-free WPSA, POFA and RHA under physico-chemical activation using flue gas desulphurisation (FGD) gypsum, for use in soft soil stabilisation. The effects of different binders produced from unary (WPSA), binary (WPSA and POFA) and ternary (WPSA, POFA and RHA) blended mixtures, along with ground and FGD gypsum activated ternary mixtures, on the geotechnical properties of soft soils, were extensively investigated. Comparisons of Atterberg limits, strength (unconfined compressive strength (UCS)), compressibility characteristics and durability (wetting-drying cycles effect) of untreated soil and soil stabilised with the optimum unary, binary, ternary and activated ternary mixtures and a reference cement treated soil, have been carried out. An investigation of the microstructural and mineralogical composition of the newly developed binder, in comparison to those of the reference cement, was also carried out using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) imaging and energy dispersive X-ray (EDX) spectroscopy analysis. The results indicate that the soil stabilised with the ternary mixture activated by FGD gypsum (T+FGD), had the greatest compressive strength, compressibility and durability improvement; the performance of the newly developed cementitious binder was comparable to that of the reference cement. This binder comprises 8% WPSA + 2% POFA + 2% RHA activated with 5% of FGD, by the total mass of binder. The addition of FGD gypsum has been observed to enhance the pozzolanic reaction, leading to improved geotechnical properties; mainly UCS which increased over time of curing and exceeded that for the soil treated with reference cement, after 180 days. The results obtained from XRD analysis, SEM testing and EDX analysis revealed the formation of hydrated cementitious products represented by calcium silicate hydrates (C-S-H), Portlandite (CH) and ettringite. The formation of these hydrates reveals the developments gained in the geotechnical properties of the treated soil. A solid, coherent and compacted soil structure was achieved after using T+FGD, as confirmed by the formation of C-S-H, CH and ettringite. Therefore, a new, Cost effect, eco-friendly and sustainable cementitious binder has been successfully developed and can be used with confidence for soft soil stabilisation, as a 100% replacement of conventional cement.

Society has gripped the concept of road transport and has utilised it for social, personal and economic gain. Amidst the apparent benefits, a number of concerns exist around the dangers, congestion, and monetary loss associated with vehicular transport. To counteract this, the introduction of driverless vehicles is being discussed by manufacturers and the Government. Whilst there are a number of apparent benefits, there is an overwhelming need to consider public perception and acceptance of autonomous vehicles. This research study therefore investigates the aforementioned, analysing and presenting the major issues and concerns related to their uptake. An interview and focus group based approach was adopted for this research, using the Charmaz (2006) constructivist grounded theory methodology. Interviews were conducted with a range of stakeholders and the results of the study detailed that the environment the vehicle and user operate in presents associated issues influencing perceptions, and that technology acceptance is strongly influenced by levels of Motivation in Intention, Acceptance/Usage and Control. Furthermore, acceptance is perceived differently by various stakeholder groups, each with their individual concerns and speculations. The discussion of the study considers the gathered perception to ascertain how best to introduce autonomous vehicles to the public market, highlighting and satisfying the current implications of doing so. This study highlights the need for further research in this discipline, based on the identification of many knowledge gaps. Further work is discussed and recommended in order to combat the limitations and opportunities identified within this thesis.

Este trabalho de pesquisa foi realizado na busca de melhor entendimento do comportamento estrutural de pavimentos de concreto no que tange a transferência de carga em juntas, de quais os fatores que influenciam essa transferência de esforços nas juntas e a determinação, em caráter preliminar, de como as condições climáticas vigentes na área tropical dos estudos afeta o fenômeno. Para a realização dos experimentos foi empregada a pista experimental USP/FAPESP, construída em 1999, e até então não empregada para a determinação dos efeitos de transferência de cargas em juntas com e sem barra de transferência de carga. Paralelamente, para retroanalisar os parâmetros de transferência de carga, foram necessárias a avaliação e a análise estrutural de respostas a carregamentos dinâmicos das placas de concreto da pista experimental, possibilitando a determinação de diversos parâmetros em jogo, em especial, do módulo de elasticidade de concretos e do módulo de reação do subleito. Os estudos permitiram determinar que a ausência de barras de transferência de cargas em juntas transversais torna menos eficiente tal transferência além de apresentar nesse caso forte dependência da temperatura do concreto. Em juntas com barras de transferência de carga, para qualquer época do ano, a transferência de cargas é sempre igual ou superior a 90%, aproximadamente, independentemente da geometria das placas. Não existindo tais dispositivos o valor da transferência de cargas variou de 60 a 75%. Não foram observadas dependências importantes quanto a diferentes níveis de carregamento durante os testes, bem como para espessuras de placas de concreto, em placas com barras de transferência. Observou-se, também, embora em escala inferior ao que se narra na literatura passada, que o módulo de reação do subleito para carga de borda é maior que aquele para carga de centro. As faixas de valores de módulos de elasticidade para concretos de placas e para concretos compactados com rolo em sub-bases coincidiram com as faixas de valores encontrados em laboratório com medidas efetuadas na época da construção dos pavimentos. O processo de retroanálise com o programa ISLAB2000 mostrou-se um recurso valioso para a parametrização dos pavimentos de concreto estudados. / This research was proposed aiming an in deep study of the mechanism of load transfer across concrete pavement joints including the analysis of which factors influence such load transfers with special regards to the climate factors as concrete temperature. The concrete pavements under study were built in 1999 as a research supported by FAPESP, whose experimental sections has not been used before for such a goal. Backcalculation techniques were employed to analyze deflection data collected with FWD tests over the slabs and it was possible to define values for the test sections materials parameters like concrete modulus of elasticity and the modulus of subgrade reaction. Tests detected loss of load transfer efficiency on the dependence of concrete temperature for non dowelled joints. For dowelled joints, whatever the season of the year or period of the day, joint load transfer efficiency was at least 90% approximately. However, without dowels, efficiency ranged from 60 to 75%. No expressive dependence on the load level was observed during tests, as well as on the slab thicknesses, for cases of dowelled joints. It was observed the increase in the value of the modulus of subgrade reaction when loads were applied in joint position, although not so expressive as sometimes described in the literature. Ranges for concrete and rolled compacted concrete modulus of elasticity resulted similar to former values got from the construction period in laboratory. Therefore, backcalculation procedures using ISLAB2000 software is understood as a valuable tool for concrete slab characterization.

Este trabalho contém relato e discussão sobre atividades e resultados obtidos durante uma tentativa para mostrar que pressiômetros e ensaios \"in situ\" podem ser úteis ao estudo de tensões e deformações de solos utilizados na construção de sub-base de pavimentos flexíveis. Verificaram-se condições para aceitar a hipótese: \"os módulos de elasticidade, estimados a partir de manuseio sobre dados obtidos através de levantamentos em campo com uso de pressiômetros PENCEL, poderão ser utilizados para estudo da relação entre tensões e deformações de solos granulares de sub-bases de pavimentos flexíveis\" - isso foi efetuado usando conceitos e estimativas de módulo de resiliência. Para isso, descreveram-se equipamentos e métodos de ensaio triaxiais com repetições de aplicações de cargas, para estimativa de módulos de resiliência, e, processos para levantamento de dados com o pressiômetro \"in situ\" nas sub-bases de pavimentos. Os dados usados foram obtidos nas rodovias BR 230 Rodovia Transamazônica e PB 055 Sapé a Guarabira, estado da Paraíba, Brasil. Estudos sobre a interseção de intervalos de confiança indicaram que, para o intervalo de tensões em sub-bases de pavimentos, as estimativas de módulos de elasticidade a partir de ensaios em campo com o uso de pressiômetros podem ser de mesma ordem de grandeza que os valores obtidos a partir de ensaios triaxiais em laboratório. / In this work it was described and discussed the actions and the results obtained in activities to show that pressuremeters and \"in situ\" test should be useful to study stress and strains of soils used on building flexible pavement sub-base. lt was verified some conditions to accept the hypothesis \"the elasticity modulus estimated from data obtained from PENCEL pressuremeter data field surveying should be used to study granular soils stress and strain in the flexible pavement sub-bases\" - this was done using the resilient modulus concepts and surveying. lt was also described methods and equipment applied to dynamic triaxial tests, and the process used to survey field data using the pressuremeter to estimate the resilient modulus. The data was obtained in sub-bases from the BR 230 The Transzamazonic Highway and PB 055 The Sape to Guarabira Highway, located in the State of Paraiba, Brazil. lt was showed that the confidence intervals intersections among the elasticity modulus obtained from pressuremeter data field surveying and laboratory triaxial tests should have the same level of values.

In 1987, Congress authorized a 5 year $150 million dollar research program called the Strategic Highway Research Program (SHRP). SHRP was divided into four major areas, including the asphalt research program. The asphalt research program was divided into six major research contracts, one such contract, SHRP-003A was called Performance Related Testing and Measuring of Asphalt Aggregate Interaction and Mixtures. Oregon State University performed the portion of this contract related to the development and validation of accelerated test procedures for aging, low temperature cracking, and moisture sensitivity of asphalt-aggreagte mixtures. This thesis contains five independent papers that discuss elements of the development, validation, and or implementation of these accelerated test procedures. In the first paper, the relationship between field performance and laboratory aging properties of asphalt-aggregate mixtures is discussed, including the relative importance of asphalt binder and aggregate type on the amount of aging experience. Based on this work recommended aging procedures are presented to simulate different environmental conditions and pavement age. The second paper makes use of the large body of resilient modulus data conducted as part of the SHRP research effort to compare data obtain in the diametral and the triaxial mode. It is not possible to give a relationship between triaxial and diametral resilient modulus, without describing specimen geometry and other test conditions. The third paper discusses the effect of aging on the thermal cracking properties of asphalt-aggregate mixtures. The temperature at which aging occurs affects the way cold temperature fracture properties change with time. Low temperatures result in quenching of the aging process, while high temperatures result in continued aging. The fourth paper discusses work conducted in association with the Oregon Department of Transportation to extend the environmental conditioning system (ECS) test procedure for moisture assessment to open graded mixtures. Comparison in the ECS of mixtures with and without anti-strip agents added indicates that they don't always decrease moisture damage potential. The final paper presents a discussion of asphalt chemistry and its relationship to asphalt-aggregate mixture performance. Using the SHRP asphalt model, aging and low temperature performance data collected at Oregon State University is explained. / Graduation date: 1995