Thesis: M.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1975 / Bibliography: leaf 95. / M.S. / M.S. Massachusetts Institute of Technology, Department of Civil Engineering

This thesis presents a study on the strength properties of the different pervious pavement systems installed at the Stormwater Management Academy field laboratory at University of Central Florida (UCF), Orlando. The strength tests were performed both in the laboratory and in the field. Laboratory testing was conducted to determine the compressive strength and flexural strength of the various pavement surfaces. Evaluation of field pavement performance was performed by comparing the deflection basins using the Falling Weight Deflectometer test on pervious concrete and porous asphalt with conventional impervious concrete and asphalt pavements of similar layer profile and thickness, respectively. From literature and previous work at the academy, it is evident that pervious pavements should not be used to withstand heavy traffic loading. They are mostly used in low traffic volume areas such as parking lots, driveways, walkways and some sub-divisional roads. This research studied the compressive strength and flexural moduli. Also it investigated the relationship between the compressive strength and void ratio, unit weight and volume by carrying out laboratory testing of different pervious pavements such as pervious concrete, porous asphalt, recycled rubber tires, recycled glass and porous aggregate. Different sizes of cylinders and beams were cast in place molds for these laboratory tests. Furthermore, the in-situ resilient moduli of the twenty four pavement sections in our research driveway were back calculated with Modulus 6.0 (Liu, et al., 2001) computer program. The calculated deflection basins were compared to the results obtained from a well known computer program called KENPAVE (Huang, 2004). The design of the requisite pavement layer thickness design was performed by doing hand calculations using American Association of State Highway Transportation Officials (AASHTO) method for flexible and rigid pavements and utilizing a Texas Transportation Institute (TTI) computer software known as FPS 19W (Liu, et al., 2006). The structural number for flexible pavements were calculated and tabulated for two different reliability levels (90% and 95%). Traffic loading was estimated in the absence of actual traffic count measurement devices at the field test site. Based on the laboratory testing, the maximum compressive strength of the cored pervious concrete was about 1730 psi. Backcalculated pervious concrete and porous asphalt moduli values were within the specified range discussed in literature. The in-situ modulus of elasticity range for pervious concrete is found to be 740 - 1350 ksi, for porous asphalt 300 - 1100 ksi, for permeable pavers 45 - 320 ksi, for recycled rubber tire 20 - 230 ksi, recycled glass pavement 850 ksi and porous aggregate 150 ksi. For low volume traffic loading, the minimum layer thickness was calculated for rigid pavements and it is presented in this study. In conclusion, this research summarizes the result of laboratory and field testing performed at the University of Central Florida Stormwater Management Academy Research laboratory to determine the strength related properties of pervious pavement systems.

No description available.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2007. / Mozambique is investing heavily in rehabilitating and upgrading the current roadway infrastructure. Investigation by the Mozambican roads authority found that some consulting engineers and contractors were not familiar with Mozambican conditions and materials. The World Bank sponsored a research project to support the roadway infrastructure preservation and maintenance efforts. The thesis work presented forms an integral part of the work conducted by the World Bank project research team. The objective of the thesis is to characterise cement stabilized sand bases in Mozambique under Accelerated Pavement Testing (APT) in terms of stiffness and deflection responses under load trafficking. This work forms the basis for developing guidelines for a mechanistic-empirical design method for Mozambican conditions and materials. Reported findings from initial MMLS3 testing conducted for the World Bank project were used to scope the full-scale research study and provided guidelines for the selection and construction of full scale test sections on natural subgrade. The APT presented encompass full-scale pavement testing including wet trafficking cycles to emulate environmental effects.

Tem-se verificado, na prática, que a falta de drenagem subsuperficial é um dos principais fatores de deterioração precoce dos pavimentos. Ainda, verifica-se que são relativamente poucos os procedimentos de dimensionamento e modelos de análise de previsão de desempenho que consideram efetivamente o efeito deletério da drenagem na vida útil dos pavimentos. No entanto, observa-se que pesquisas e experiências estrangeiras não estabeleceram ainda uma correlação quantitativa confiável entre a presença dos dispositivos de drenagem e o desempenho dos mesmos. No trabalho foi realizada análise de sensibilidade dos modelos da AASHTO (versão de 1993) e HDM-4, considerados os mais difundidos na atualidade. Os modelos empregam coeficientes de drenagem para a consideração dos efeitos danosos da presença de água livre no interior de estruturas de pavimentos rígidos e flexíveis. Teoricamente, verificou-se que os modelos são sensitivos quanto à influência das condições de drenagem no desempenho dos pavimentos. Foram analisados dados reais de certa malha viária no interior do estado de São Paulo e verificou-se, na prática, que os pavimentos flexíveis sem acostamento pavimentado, ou seja, com condições precárias de drenagem, têm apresentado desempenho inferior quando comparados com estruturas dotadas de acostamentos pavimentados mais impermeáveis. Constatou-se a dificuldade de se adotar os coeficientes de drenagem nos modelos analisados, apesar da grande importância da fixação adequada no dimensionamento. Comenta-se no trabalho que, além da existência de dispositivos de drenagem subsuperficial, é necessário checar a sua continuidade e capacidade hidráulica ao longo de todo o sistema. Sugerem-se procedimentos para o dimensionamento hidráulico do sistema de drenagem de pavimentos e a necessidade de se considerar a avaliação econômica ao longo de um período, de acordo com o desempenho esperado do pavimento (LCCA - Life Cycle Cost Analysis) quando da definição da concepção de pavimentos rodoviários drenantes, principalmente quando submetidos a tráfego pesado e em condições climáticas desfavoráveis. / There has been verified, in practice, that the absence of pavement drainage is one of the main factors of early degradation of pavements. More, there are few procedures of design and performance analysis that effectively consider the damage of water during the design period. However, foreign experiments and researches do not establish a reliable correlation between the construction of pavement drainage features and pavement performance. In this text, there has been analyzed the AASHTO (version of 1993) and HDM-4 models, considered the most spread out in the present time. These models consider the damage effects of free water inside flexible or rigid pavement structures. Theoretically, it was verified that the models are sensitive about the influence of the conditions of draining in the pavement performance. It had been analyzed real data of certain roadway network in the interior of the state of São Paulo and it was verified, in practical, that the flexible pavements without paved shoulder, that is, with precarious conditions of drainage, have presented lower performance when compared with structures endowed with paved shoulders more impermeable. It was evidenced the difficulty of adopting the drainage coefficients in the analyzed models, although the great importance of the setting adjusted in the design. It is commented that, beyond the existence of devices of subsurface draining, is necessary to check its continuity and hydraulical capacity throughout the system. It\'s suggested procedures for the hydraulical design of the pavement drainage system and the necessity of considering the economic evaluation throughout a period, in accordance with the waited performance (LCCA - Life Cycle Cost Analysis) when the definition of the conception of road pavements, mainly when submitted the heavy traffic and in unfavorable climatic conditions.

Flexible or asphalt pavements constitute nearly 94% of the 2.7 million miles of existing roadways in the United States. In a typical rehabilitation project, the existing asphalt pavement is milled up to a prescribed depth for removing the near surface distresses such as excessive cracking and rutting, and a new overlay is placed. The average time between resurfacing projects varies depending on the level of pavement deterioration which is significantly accelerated when poor subgrade conditions are encountered. The use of geosynthetic reinforcement within the new asphalt overlay is often perceived as a mitigation strategy that can delay the onset and propagation of reflection cracking, and also control the rutting and differential settlement. However, some mixed reviews about the performance of the geosynthetic reinforced overlays have been reported in the literature. In Phase I of this study, a laboratory investigation was conducted for evaluating the flexural fatigue behavior, permanent deformation response, and fracture characteristics of geogrid reinforced asphalt beam specimens made from a typical overlay material. The laboratory specimens included geogrid as a single-layer inclusion either at the bottom third depth or at the mid height, and as double-layer inclusion, with geogrid placed both at the bottom third and at the middle of the beam. In Phase II, a case study involving geogrid reinforced overlay constructed over a deteriorated pavement underlain by soft subgrade in southeastern Florida was numerically simulated. It was found that the geogrid reinforcement significantly improved the fatigue and fracture properties of the asphalt beams compared to unreinforced specimens. Results from numerical simulation demonstrated that the double reinforced overlay resulted in the minimum tensile stress at the bottom of the asphalt layer (reducing the cracking potential) and minimum vertical strain on the top of the subgrade (reducing the rutting potential), compared to unreinforced or bottom-third reinforced overlays. Accordingly, it is concluded that the double layer reinforcement of asphalt overlays with an appropriate geosynthetic product can be beneficial for the performance and long term preservation of the pavement system when soft soils are encountered. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

Este trabalho tem por objetivo estudar todas as parcelas de custos que envolvem os pavimentos flexíveis e rígidos durante sua vida em serviço, abordando os custos de construção, de manutenção e reabilitação e os custos de operação dos veículos. Inicialmente, tem-se a análise dos métodos utilizados para o dimensionamento dos pavimentos flexíveis e rígidos, bem como dos custos associados a diferentes procedimentos construtivos utilizados no Brasil, visando o estabelecimento dos custos de construção. Os custos de manutenção e reabilitação são determinados a partir da identificação das principais formas de deterioração dos pavimentos. Os custos de operação dos veículos, que incidem diretamente sobre os usuários e dependem, principalmente, da condição da superfície de rolamento, são calculados com base em modelos de desempenho de programas de gerência de pavimentos utilizados por organismos rodoviários brasileiros. Para uma maior abrangência da análise comparativa de pavimentos flexíveis e rígidos foi elaborada uma programação fatorial de simulações. A comparação dos custos dos pavimentos flexíveis e rígidos é proveniente da análise dos custos totais obtidos para todas as combinações de fatores intervenientes (células da matriz fatorial). Os fatores utilizados são: tipo de subleito, materiais e espessuras das camadas (métodos de dimensionamento), solicitações e volume de tráfego e estratégia de manutenção e reabilitação dos pavimentos. / This research work aims to determine and compare the total cost for both, rigid and flexible pavements. Thus, it analyzes all components of costs related to flexible and rigid pavements during their service lives, i.e., construction cost, maintenance and rehabilitation cost and users cost. For the determination of the construction cost it is considered the most used pavement design methods, as well construction procedures used in Brazil. The maintenance and rehabilitation cost is calculated based on the identification of the main distress types for both flexible and rigid pavements that occur in Brazil. The users cost, function of the pavement surface condition, is calculated from performance models used by Brazilian highway agencies. For a broader comparison of rigid and flexible pavements it is performed a factorial analysis. The main factors to be considered are: subgrade type, pavement layer material and thickness, traffic load and volume, maintenance and rehabilitation strategy. The simulations for the determination of total cost will be done for each cell of the factorial matrix, i.e., for each combination of factors.

The western and northern parts of South Florida have shallow layers of organic and plastic soils under existing roads. These roads often exhibit large amount of cracking and distortion in a short period of time. Traditional repairs are often not practical due to high costs and extended construction time. In an effort to develop rehabilitation strategies that could be strictly applied to the surface layer, a pilot test site was selected along the alignment of SR 15/US 98 in northwest Palm Beach County, where severe pavement distresses were observed due to the presence of thick organic layers. PaveTrac MT-1, GlasGrid 8501, PetroGrid 4582, and ARMI were used as promising asphalt reinforcing products in 24 experimental pavement sections, including 8 control sections without any reinforcement. A comprehensive field testing and monitoring program involving FWD, rut and ride quality measurements was conducted at the preconstruction, 6-month post-construction, and 18-month post-construction stages. Due to large variability in the sub-surface conditions, a statistics-based data analysis protocol was developed for performance evaluation and relative comparisons of the test sections and, in turn, reinforcing products. Post construction data from both 6 months and 18 months demonstrated that stiffness of reinforced sections were significantly higher than the control sections. Procedures were developed to identify and statistically quantify the benefits derived from the reinforcements only, so that the relative performance of various products could be monitored over time. Based on the field testing data available to date, a framework was developed in this study for the prediction of pavement life, which is essential for conducting a detailed Life Cycle Analysis / by Alex Lima-Arie. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

Este trabalho tem por objetivo estudar todas as parcelas de custos que envolvem os pavimentos flexíveis e rígidos durante sua vida em serviço, abordando os custos de construção, de manutenção e reabilitação e os custos de operação dos veículos. Inicialmente, tem-se a análise dos métodos utilizados para o dimensionamento dos pavimentos flexíveis e rígidos, bem como dos custos associados a diferentes procedimentos construtivos utilizados no Brasil, visando o estabelecimento dos custos de construção. Os custos de manutenção e reabilitação são determinados a partir da identificação das principais formas de deterioração dos pavimentos. Os custos de operação dos veículos, que incidem diretamente sobre os usuários e dependem, principalmente, da condição da superfície de rolamento, são calculados com base em modelos de desempenho de programas de gerência de pavimentos utilizados por organismos rodoviários brasileiros. Para uma maior abrangência da análise comparativa de pavimentos flexíveis e rígidos foi elaborada uma programação fatorial de simulações. A comparação dos custos dos pavimentos flexíveis e rígidos é proveniente da análise dos custos totais obtidos para todas as combinações de fatores intervenientes (células da matriz fatorial). Os fatores utilizados são: tipo de subleito, materiais e espessuras das camadas (métodos de dimensionamento), solicitações e volume de tráfego e estratégia de manutenção e reabilitação dos pavimentos. / This research work aims to determine and compare the total cost for both, rigid and flexible pavements. Thus, it analyzes all components of costs related to flexible and rigid pavements during their service lives, i.e., construction cost, maintenance and rehabilitation cost and users cost. For the determination of the construction cost it is considered the most used pavement design methods, as well construction procedures used in Brazil. The maintenance and rehabilitation cost is calculated based on the identification of the main distress types for both flexible and rigid pavements that occur in Brazil. The users cost, function of the pavement surface condition, is calculated from performance models used by Brazilian highway agencies. For a broader comparison of rigid and flexible pavements it is performed a factorial analysis. The main factors to be considered are: subgrade type, pavement layer material and thickness, traffic load and volume, maintenance and rehabilitation strategy. The simulations for the determination of total cost will be done for each cell of the factorial matrix, i.e., for each combination of factors.

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