Rural roads play a crucial role in the economic and social development of societies, linking rural communities to education, health services and markets. During the last decade, considerable efforts have been made to evaluate the benefits of rural road investment in developing countries. Although outputs of these studies have led to a global rethinking of traditional road appraisal methods, limited attempts have been made to integrate these findings to the rural road management process. For the sustainable management of rural roads, social, institutional, technical, economic and environmental aspects should be considered under a long term perspective. The current practice in developing countries is that only some of these key sustainable aspects are being considered in the management process. In addition, rural roads maintenance management is commonly performed under a short term basis, not considering the life cycle costs and benefits in the economic analysis and project prioritization. Available management tools and studies have essentially focused their efforts on improving technical and economic aspects of low-volume roads. Whereas, the common practice observed in face of limited resources and lack of technical skills is that decisions are made under a political short term perspective. This research is directed at the development of an applied and practical system for the sustainable management of rural road networks in developing countries. The approach considers the development of all components required by the proposed management system and their integration into a practical and easy-to-use computer tool. To achieve this goal a sustainable framework for rural roads management was first developed, where system components and modules were defined. A network level condition evaluation methodology was selected and validated. Long term condition performance models were calibrated from the probabilistic analysis of field data. Optimal maintenance standards were developed under a cost-effectiveness approach. A long term prioritization procedure was developed to account for sustainable aspects of rural roads in the management process. A computer tool was finally developed to integrate the system components and display them in a friendly interface for potential users. The tool was programed in Visual Basic, considering Microsoft Excel interface. The computer tool considers the four system components: Input Data, System Modules, Network Analysis Interface and Output Data. System Modules include Condition Performance Module, Network Maintenance Module and Long Term Prioritization Module. For each of the system components and modules a separate worksheet has been included in the computer tool. The tool is centered on the Network Analysis Interface, which interacts with the other three system components. The user enters network data in the Input Data interface and may adjust information in System Modules considered if the network under study has differences to predefined conditions of. Adjustments to System Modules can be performed by the user, however it is advised that prior calibration is required for the successful analysis of the network. The management system was applied and validated in two rural road networks in developing countries located in Chile and Paraguay. Sensitivity analysis was carried out to assess the impacts of input parameters in the performance of developed system. As a result of the research an adaptable and adoptable sustainable management system for rural networks was developed to assist local road agencies in developing countries.

Tropical regions have extensive networks of unpaved roads which can be the largest contributor of sediment loading within a watershed in terms of both sediment generation and delivery. A number of erosion and sediment prediction models have been developed for unpaved roads and applied across a wide range of locations. However, little work has been devoted to the comparison of these models or to their application in tropical environments. A 13 square kilometer mixed land use watershed in Eastern Brazil was used as a case study area for model application and comparison. Models chosen for evaluation were WEPP: Road, SEDMODL, and STJ-EROS. To determine the applicability of these models to the case study watershed, a classification system was developed to score road segments according to sediment production and delivery potential. Field observations provided data for the input parameters of the models as well as to identify which road segments appear to be high contributors of sediment within the watershed. These road segments were compared with the segments estimated by the models to have high sediment yields. The models identified less than 50% of those roads categorized by field observation as having high erosion potential. WEPP: Road matched more closely to the field observations than SEDMODL and STJ-EROS. To be useful tools for watershed management in the tropics, a unified method for calculating sediment delivery is needed as well as an adjustment to model input parameters so that they better reflect conditions in tropical watersheds. / Master of Science

Master of Science / Department of Civil Engineering / Dunja Peric / The purpose of this research was to investigate the effects of drying on the strength gain of masonry sand stabilized with a co-product from wood pulping called calcium lignosulfonate. Lignin is an amorphous polymer found in plant cell walls. It provides protection against disease and allows the transport of water and nutrients. Adhesive properties of lignin generated interest in adding its modifications to soils as means to prevent erosion from wind and vehicle traffic on unpaved roads. Lignin has the potential to become a more sustainable alternative to traditional stabilizers because its source is renewable and abundant, and its toxicity is negligible. Extensive testing has recently been completed to quantify the stress-strain relationships and Mohr-Coulomb strength parameters of sand- calcium lignosulfonate-water (S-CaL-W) mixes at early age (Bartley, 2011). The experimental program consisted of performing Standard Proctor Tests to determine maximum densities and optimum moisture contents for mixes having different gravimetric lignin contents and direct shear tests on selected sample configurations. Based on these results, it was decided to conduct shear strength testing of the samples containing 4%, 6% and 9% of calcium lignosulfonate after they had been exposed to air drying. To this end, responses of the selected sample configurations to drying at 71° F and 27% relative humidity were measured to determine the target water contents for shear strength testing. Drying curves were obtained by plotting the measured water content or water to CaL ratio versus the elapsed time. Drying times for shear strength were chosen based on how long it took the moisture contents to decrease by specified levels. The available results of direct shear tests show that drying significantly increases both the cohesion and the friction angle of the S-CaL-W mixes with respect to the early age cohesion and friction angle. In addition to the direct shear test program a laboratory compaction test was conducted on CaL and water only, thus providing the maximum dry density of CaL and the corresponding optimum water to CaL ratio. It is also noted that relative humidity was discovered to be the limiting factor in the strength gain of S-CaL-W mixes. The reasons behind its sensitivity to water are due to the presence of HPLC sugars within the calcium lignosulfonate structure. These sugars hold the water through the chemical interaction of the sugars with hydrogen ions and water molecules.

Simple unpaved roads consist of a layer of coarse granular material placed directly onto the surface of weak or compressible ground. It is thought that the construction of such roads can be considerably improved by the incorporation of a geogrid at the base of the granular fill layer. Geogrids are a type of geotextile, distinguished by their relatively large aperture size. Laying out a geogrid on the surface of the ground before placing the fill layer may in many cases allow a reduced thickness of fill material to be used, and may also substantially increase the load required to cause a complete failure of the system. No generally accepted design method exists for the construction of reinforced unpaved roads, due to the complex mechanisms which govern deformations in the system. The primary aim of this dissertation was to investigate the performance, in such a construction, of a particular geogrid, namely Tensar, manufactured by Netlon Ltd. A detailed model study into failure mechanisms was undertaken using laboratory apparatus constructed to conduct work at 1/4 full scale. Simple plane-strain, monotonic footing tests were carried out on systems consisting of a fill layer compacted onto a consolidated clay subgrade, both with and without the incorporation of a model grid at their interface. The testing technique included a comprehensive study of photographs taken of marker movements in the clay through the transparent sides of the test-box during tests. The relevant failure mechanisms associated with reinforced and unreinforced systems were established. In addition the significance of shear stresses acting at the subgrade surface was recognised and a concept whereby the appropriate subgrade bearing capacity factor is related to these shear stresses was developed. The modelling techniques adopted in this work obviated the need for a centrifuge.

The purpose of this study is to obtain an insight into the mechanisms by which a geosynthetic membrane influences the performance of a plane strain and an axisymmetric two-layer soil system, where the reinforcement is incorporated either into a layer of fill, or at the interface of a layer of fill overlying clay subgrade. New axisymmetric membrane and interface element formulations are developed and incorporated in to an existing large strain finite element code. A linear elastic model of behaviour is used for the membrane material and an elastic-perfectly frictional model, based on the Mohr-Coulomb yield function, is implemented for the interface. These new formulations both take account of large global displacement and rotation effects, although the interface element is constrained to small relative displacements, and are checked against small and large strain closed form test problems. The finite element equations are based on an Updated Lagrangian description of deformation. Plane strain finite element investigations into the significance of the resolution and relative size of the finite element mesh, and the differences between large and small strain analyses, are undertaken. For typical unreinforced and reinforced plane strain and axisymmetric two- layer soil systems a detailed analysis is presented of the soil displacements, strains, stresses, principal stress directions, mobilised fill friction angles and the stresses on the underside of the footing. A series of plane strain and some axisymmetric parametric studies of the various material properties is conducted, to assess the influences and relative importance of those variables to the performance of the two-layer soil system under monotonic loading. The study considers various reinforcement lengths and stiffnesses, fill depths and strengths, and different clay strengths. The mechanisms of reinforcement are identified through careful examination of the footing load-displacement response, the reinforcement tension and the stresses and displacements at the interfaces with the surrounding soil. A comparative study is also undertaken between the results obtained by the finite element model and those predicted by a plane strain and axisymmetric limit equilibrium design method. The effects of including a low friction membrane within an oil storage tank base, as secondary containment against oil leakage, are investigated by a series of axisymmetric finite element analyses.

A series of finite element predictions of the behaviour of a reinforced unpaved road consisting of a layer of fill compacted on top of a clay subgrade with rough, thin reinforcement placed at the interface, is described in this thesis. These numerical solutions are obtained using a large strain finite element formulation that is based on the displacement method, and are restricted to the case of plane strain, monotonic loading. Separate elements are used to model the soil and reinforcement. In the finite element formulation, an Eulerian description of deformation is adopted and the Jaumann stress rate is used in the soil constitutive equations. Elastic perfectly-plastic soil models are used which are based on the von Mises yield function for cohesive soil and the Matsuoka criterion for frictional material. Emphasis is placed on obtaining new closed form solutions to parts of calculations that are performed numerically in many existing finite element formulations. The solution algorithm is based on a "Modified Euler Scheme". The computer implementation of the formulation is checked against an extensive series of test problems with known closed form solutions. These include the analysis of finite deformation of a single element of material and the calculation of small strain collapse loads. Finite cavity expansion is also studied. This numerical formulation is used to perform back analyses of a series of reinforced unpaved road model tests. The reinforcement tensions, and the stresses at the interface with the surrounding soil, are calculated using the numerical model and discussed with a view to identifying the mechanisms of reinforcement. Two existing analytical design models of the reinforced unpaved road are described and critically reviewed in the light of the finite element results.

The mechanisms by which a geogrid acts to reinforce a granular layer over a soft clay were investigated with reference to trafficking of unpaved roads. The research involved a programme of physical testing at both model and full scale. Model tests were carried out for monotonic and cyclic loading of a dual footing on to a layer of granular material that was compacted over a consolidated kaolin sample. The tests were made in conditions of plane strain at a quarter scale, and included a scaled geogrid at the base of the granular layer. Measurements of footing load, displacements and photographic observations through a perspex front face to the test box were used to identify the reinforcing actions of the geogrid. A virtual work procedure was adopted in analysis of the results for both unreinforced and reinforced layers. The procedure accounts for lateral restraint of the subgrade and a membrane action in the reinforced tests, and allows a comparison of the cyclic test results with an equivalent monotonic bearing capacity. Load tests were also made on footing plates at full scale, involving a similar arrangement of compacted granular layers over prepared London clay and including a high strength polymer geogrid. Examination of the test results allowed a qualitative assessment of the model performance and the reinforcing mechanisms attributed to the geogrid.

The aim of the work was to assess and evaluate the historical development of road networks from the view of their projection in a comprehensive land adjustment. For this purpose, three cadastral areas, that represent a wide range of natural conditions, were chosen. Historical stages, in which the road network has been captured, were determined and studied in detail. To create an overview of the unpaved roads, evaluation criteria, by which individual areas were selected and compared in the chosen historical stages, were designed. On the basis of the results, the turning points of unpaved roads development were determined and their causes were described. The accomplished analysis of the road network in particular historical periods gives a clear overview in development of unpaved roads and arrangement of individual land lines. Historical image of unpaved road network, as an integrated complex, can be used only as inspirational material within the plan projection. This material has to be revised according to current legislation requirements, standards and wishes of landowners.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-04-30T14:00:58Z No. of bitstreams: 2 Tese - Alisson Neves Harmyans Moreira - 2018.pdf: 21405657 bytes, checksum: 4b00145f027dd4633e7297ae895827dc (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-04-30T14:03:19Z (GMT) No. of bitstreams: 2 Tese - Alisson Neves Harmyans Moreira - 2018.pdf: 21405657 bytes, checksum: 4b00145f027dd4633e7297ae895827dc (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-04-30T14:03:19Z (GMT). No. of bitstreams: 2 Tese - Alisson Neves Harmyans Moreira - 2018.pdf: 21405657 bytes, checksum: 4b00145f027dd4633e7297ae895827dc (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-04-12 / Unpaved roads are important access routes to urban centers, serving to facilitate the traffic of vehicles for socioeconomic purposes. In order to ensure the flow of goods produced and the transport of people, it is necessary that this road network has adaptations in order to prevent them from becoming channels and, consequently, erosion processes. In this sense, it is necessary to elaborate planning practices for the conservation of these roads. By means of field surveys and geomorphological databases, this study aimed to recommend and quantify the drainage devices for the sub-basin of the Olaria stream with the aid of a Geographic Information System (GIS), as well as to compare these with recommended devices from the Estradas model. The drainage devices used in the study were energy drains in the drainage channel and energy dissipaters in ditches. The recommendation of the drainage devices through the GIS were from geomorphometric and soil matrix databases. These data support the modeling, together with the geometric elements of the roads and the physical-water data of the soils of the beds and adjacencies. It was used data of reliefs from the image of the Topodata project, with accuracy and vertical precision of 5,529 m and 2,217 m, respectively. These results met the Class A Cartographic Accuracy Standard (PEC) for the representation of altimetric data in the 1:50.000 scale. Regarding the morphometric data of the segments, 90% of the slopes were compatible between the reference values of the GPS Geodesic receiver and the tested values of Topodata, thus obtaining the same recommendations for spines with water outlets. For the 50.1 km of unpaved roads in the subbasin of the Olaria stream, the GIS showed that only 12.1% of the segments did not require springs with water exits. It was recommended 953 water bars with outlets and 83 energy dissipaters in ditches. It was noted that the incompatibilities in the recommendations are related to the variables involved. Therefore, the geometric tracing and the excessive recommendations of these drainage devices by the GIS show that criteria such as relief and the soils were ignored in the implantation of the unpaved roads. / As estradas não pavimentadas são importantes vias de acessos aos centros urbanos, servindo para facilitar o tráfego de veículos para fins socioeconômicos. Para assegurar o fluxo de bens produzidos e o transporte de pessoas é necessário que essa rede viária tenha adequações a fim de evitar que se transformem em canais e, consequentemente, ocorram processos erosivos. Nesse sentido, é necessária a elaboração de práticas de planejamento para a conservação dessas vias. Por meio de pesquisas de campo e bases de dados geomorfológicas, este estudo teve como objetivo recomendar e a quantificar os dispositivos de drenagem para a sub-bacia do córrego Olaria com o auxílio de um Sistema de Informação Geográfica (SIG), bem como comparar estes dados com os dispositivos recomendados a partir do modelo Estradas. Os dispositivos de drenagem utilizados no estudo foram os dissipadores de energia em canal de drenagem e as lombadas com saídas d’água. A recomendação dos dispositivos de drenagem por meio do SIG foram a partir de bases de dados matriciais geomorfométricas e de solos. Estes dados subsidiaram a modelagem, juntamente com os elementos geométricos das estradas e os dados físico-hídricos dos solos dos leitos e adjacências. Utilizou-se dados de relevos a partir da imagem do projeto Topodata, com acurácia e precisão vertical de 5,529 m e 2,217m, respectivamente. Esses resultados atenderam a classe A do Padrão de Exatidão Cartográfica (PEC) para a representação de dados altimétricos na escala de 1:50.000. No que tange aos dados morfométricos dos segmentos, 90% das declividades foram compatíveis entre os valores de referência do receptor GPS Geodésico e os valores testados do Topodata, obtendo assim, as mesmas recomendações para as lombadas com saídas d’água. Para os 50,1 km de estradas não pavimentadas na sub-bacia do córrego Olaria, o SIG evidenciou que apenas 12,1% dos segmentos não necessitaram de lombadas com saídas d’água. Foram recomendadas 953 lombadas com saídas d’água e 83 dissipadores de energia em sarjetas. Notou-se que as incompatibilidades nas recomendações estão relacionadas as variáveis envolvidas. Por conseguinte, o traçado geométrico e o excesso de recomendações desses dispositivos de drenagem pelo SIG evidenciam que critérios como o relevo e os solos foram ignorados na implantação das estradas não pavimentadas.

Master of Science / Department of Biological & Agricultural Engineering / Ronaldo G. Maghirang / Large cattle feedlots emit considerable amounts of particulate matter (PM), including TSP (total suspended particulates), PM[subscript]10 (PM with equivalent aerodynamic diameter of 10 μm or less), and PM[subscript]2.5 (PM with equivalent aerodynamic diameter of 2.5 μm or less). Particulate emissions result from pen surface disturbance by cattle hoof action, vehicle traffic on unpaved roads and alleyways, and wind erosion. Research is needed to determine concentrations of various size fractions, size distribution, and emission rates from various sources in feedlots. This research was conducted to measure particle size distribution using laser diffraction method and estimate emissions from unpaved roads and wind erosion. Particle size distribution and concentrations of PM[subscript]10 and PM[subscript]2.5 at a commercial cattle feedlot in Kansas (Feedlot 1) were measured over a 2-yr period. The feedlot had a capacity of 30,000 head and total pen area of 50 ha and was equipped with a sprinkler system for dust control. Collocated low-volume samplers for TSP, PM[subscript]10, and PM[subscript]2.5 were used to measure concentrations of TSP, PM[subscript]10, and PM[subscript]2.5 at the upwind and downwind edges of the feedlot. Dust samples that were collected by TSP samplers were analyzed with a laser diffraction analyzer to determine particle size distribution. Particle size distribution at the downwind edge of the feedlot was also measured with micro-orifice uniform deposit impactor (MOUDI). The laser diffraction method and MOUDI did not differ significantly in mean geometric mean diameter (13.7 vs. 13.0 μm) but differed in mean geometric standard deviation (2.9 vs. 2.3). From laser diffraction and TSP data, PM[subscript]10 and PM[subscript]2.5 concentrations were also calculated and were not significantly different from those measured by low-volume PM[subscript]10 and PM[subscript]2.5 samplers (122 vs. 131 μg/m[superscript]3 for PM[subscript]10; 26 vs. 35 μg/m[superscript]3 for PM[subscript]2.5). Both PM[subscript]10 and PM[subscript]2.5 fractions decreased as pen surface moisture contents increased, while the PM[subscript]2.5/PM[subscript]10 ratio did not change much with pen surface moisture content. Published emission models were used to estimate PM[subscript]10 emissions from unpaved roads and wind erosion at Feedlot 1 and another nearby feedlot (Feedlot 2). Feedlot 2 had a capacity of 30,000 head, total pen surface area of 59 ha, and used water trucks for dust control. Estimated PM[subscript]10 emissions from unpaved roads and wind erosion were less than 20% of total PM[subscript]10 emissions obtained from inverse dispersion modeling. Further research is needed to establish the applicability of published emission estimation models for cattle feedlots.