Energy harvesting technologies have drawn much attention as an alternative power source of roadway accessories in different scales. Piezoelectric energy harvesting consisting of PZT piezoceramic disks sealed in a protective package is developed in this work to harness the deformation energy of pavement induced by traveling vehicles and generate electrical energy. Six energy harvesters are fabricated and installed at the weigh station on I-81 at Troutville, VA to perform on-site evaluation. The electrical performance of the installed harvesters is evaluated by measuring the output voltage and current generated under real traffic. Instant and average power outputs are calculated from the measured waveforms of output voltage and current. The analysis of the testing results shows that the electrical productivity of the energy harvesters are highly relevant to the axle configuration and magnitude of passing vehicles. The energy transmission efficiency of the energy harvester is also assessed. / Ph. D.

Geosynthetic reinforcement was utilized in the construction of eighteen laboratory flexible pavement test sections. The test sections were designed to simulate a low- traffic volume secondary road built over a weak subgrade. Three types of geosynthetics were used: two types of woven geotextiles; and a geogrid. The test sections were constructed, cyclically loaded, and the resulting data were collected and analyzed. The performance of reinforced test sections was compared to that of unreinforced sections to estimate any improvement due to the reinforcement. The test sections were loaded dynamically at a frequency of 0.5 Hz using a computer controlled loading system. The loading system imparted a force of 9,000 Ibs (40 kN) to the pavement surface. The load was transn1itted to the pavement surface by a 12 in (30.54 cm) diameter rigid steel plate, which approximated a dual tire load from an 18 kip (80 kN) truck axle. Both the forces applied to the steel load plate and the deflections of the pavement surface were monitored using a computer-controlled data acquisition system. The deflection of the pavement surface was measured using an array of LVDTs. An analysis and comparison of the cumulative displacement of the pavement surface due to the number of applied loads was performed for the test sections. Load induced dynamiC and cumulative vertical earth pressures within the subgrade were monitored, analyzed, and compared for a series of reinforced and unreinforced test sections. Composite section stiffness was calculated and compared among test sections with similar subgrade CBR values. / Master of Science

The Mechanistic Empirical Pavement Design Guide (MEPDG) developed by the National Cooperative Highway Research Program (NCHRP) project 1-37A, is a very powerful tool for the design and analysis of pavements. The designer utilizes an iterative process to select design parameters and predict performance, if the performance is not acceptable they must change design parameters until an acceptable design is achieved. The design process has more than 100 input parameters across many areas, including, climatic conditions, material properties for each layer of the pavement, and information about the truck traffic anticipated. Many of these parameters are known to have insignificant influence on the predicted performance During the development of this procedure, input parameter sensitivity analysis varied a single input parameter while holding other parameters constant, which does not allow for the interaction between specific variables across the entire parameter space. A portion of this research identified a methodology of global sensitivity analysis of the procedure using random sampling techniques across the entire input parameter space. This analysis was used to select the most influential input parameters which could be used in a streamlined design process. This streamlined method has been developed using Multiple Adaptive Regression Splines (MARS) to develop predictive models derived from a series of actual pavement design solutions from the design software provided by NCHRP. Two different model structures have been developed, one being a series of models which predict pavement distress (rutting, fatigue cracking, faulting and IRI), the second being a forward solution to predict a pavement thickness given a desired level of distress. These thickness prediction models could be developed for any subset of MEPDG solutions desired, such as typical designs within a given state or climatic zone. These solutions could then be modeled with the MARS process to produce am “Efficient Design Solution” of pavement thickness and performance predictions. The procedure developed has the potential to significantly improve the efficiency of pavement designers by allowing them to look at many different design scenarios prior to selecting a design for final analysis.

Neste trabalho são estudados os principais parâmetros do projeto estrutural de pavimentos rodoviários e de pisos industriais de concreto. Faz-se um levantamento bibliográfico, apresentando as características estruturais de diversos tipos de pavimentos rígidos. São discutidas as ações diretas e as indiretas em pavimentos de concreto e analisadas as formas de consideração das forças aplicadas. São apresentados modelos para representação da fundação, do pavimento e dos materiais. É feito um resumo da teoria de Westergaard, para determinação de tensões devidas ao tráfego, e da teoria de Bradbury, para determinação de tensões devidas ao empenamento. O comportamento dos pavimentos rígidos sob diversas configurações de carregamento são analisadas com auxílio de software com base no método dos elementos finitos. Apresentam-se os métodos indicados pelo DNER para determinação da espessura de pavimentos de concreto simples. São discutidas equações para determinação da área de aço para combate à retração e desenvolvido um procedimento para dimensionamento da armadura de flexão, com base na revisão da NB-1. São analisados os mecanismos de formação de fissuras e a importância das juntas. São apresentadas equações para dimensionamento das barras de transferência e das barras de ligação e analisada a influência da eficiência da junta nos esforços das placas. São desenvolvidos exemplos numéricos sobre dimensionamento de pavimentos de concreto simples e de concreto armado, e sobre detalhamento das juntas / In this work are studied the main parameters of the structural project of concrete highway and industrial pavements. A bibliographical rising is made presenting the structural characteristics of several types of rigid pavements. Direct and indirect actions in the concrete pavements are discussed and the procedures of load consideration are analyzed. Models for represent the foundation, the pavement and the materials are showed. A summary of Westergaard’s theory for determination of stresses owed to the traffic and of Bradbury’s theory for determination of stresses owed to the curling is presented. The behavior of rigid pavements under several loading configurations is analyzed, with a software based on finite elements method. The thickness design methods for concrete pavement indicated by DNER are presented and discussed. The equation for determination of shrinkage reinforcement is showed and a procedure for design of positive steel is developed, based on the brazilian code. The cracking mechanism and the importance of joints are analyzed. Design equations for dowels and tie bars are studied. Numeric design examples are developed for plain concrete pavements, for reinforced concrete pavement, and for design of the joints

Although evidence is mounting that asphalt binder oxidizes in pavements, and that oxidation and subsequent hardening of asphalt binder has a profound effect on pavement durability, important implementation issues remain to be better understood. Quantitative assessment of asphalt binder oxidation for a given pavement is a very important, but complex issue. In this dissertation, a fundamentals-based oxygen transport and reaction model was developed to assess quantitative asphalt binder oxidation in pavements. In this model, oxygen transport and reaction were described mathematically as two interlinked steps: 1) diffusion and/or flow of oxygen from the atmosphere above the pavement into the interconnected air voids in the pavement; and 2) diffusion of oxygen from those air voids into the adjoining asphalt-aggregate matrix where it reacts with the asphalt binder. Because such a model calculation depends extensively on accurately representing pavement temperature, understanding oxygen diffusivity in asphalt binders and mastics, and characterizing air voids in pavements, these key model elements were studied in turn. Hourly pavement temperatures were calculated with an improved one-dimensional heat transfer model, coupled with methods to obtain model-required climate data from available databases and optimization of site-specific pavement parameters nationwide; oxygen diffusivity in binders was determined based on laboratory oxidation experiments in binder films of known reaction kinetics by comparing the oxidation rates at the binder surface and at a solid-binder interface at the film depth. The effect of aggregate filler on oxygen diffusivity also was quantified, and air voids in pavements were characterized using X-ray computed tomography (X-ray CT) and image processing techniques. From these imaging techniques, three pavement air void properties, radius of each air void (r), number of air voids (N), and average shell distance between two air voids (rNFB) were obtained to use as model inputs in the asphalt binder oxidation model. Then, by incorporating these model element improvements into the oxygen transport and reaction model, asphalt binder oxidation rates for a number of Texas and Minnesota pavements were calculated. In parallel, field oxidation rates were measured for these corresponding pavement sites and compared to the model calculations. In general, there was a close match between the model calculations and field measurements, suggesting that the model captures the most critical elements that affect asphalt binder oxidation in pavements. This model will be used to estimate the rate of asphalt binder oxidation in pavements as a first step to predicting pavement performance, and ultimately, to improve pavement design protocols and pavement maintenance scheduling.

There is a growing interest for the use of mechanistic procedures and analytical methods in the design and evaluation of pavement structure rather than empirical design procedures. The mechanistic procedures rely on predicting pavement response under traffic and environmental loading (i.e., stress, strain, and deflection) and relating these responses to pavement field performance. A research program has been developed at the Center for Pavement and Transportation Technology (CPATT) test track to investigate the impact of traffic and environmental parameters on flexible pavement response. This unique facility, located in a climate with seasonal freeze/thaw events, is equipped with an internet accessible data acquisition system capable of reading and recording sensors using a high sampling rate. A series of controlled loading tests were performed to investigate pavement dynamic response due to various loading configurations. Environmental factors and pavement performance were monitored over a two-year period. Analyses were performed using the two dimensional program MichPave to predict pavement responses. The dynamic modulus test was chosen to determine viscoelastic properties of Hot Mix Asphalt (HMA) material. A three-step procedure was implemented to simplify the incorporation of laboratory determined viscoelastic properties of HMA into the finite element (FE) model. The FE model predictions were compared with field measured pavement response. Field test results showed that pavement fully recovers after each wheel pass. Wheel wander and asphalt mid-depth temperature changes were found to have significant impact on asphalt longitudinal strain. Wheel wander of 16 cm reduced asphalt longitudinal strains by 36 percent and daily temperature fluctuations can double the asphalt longitudinal strain. Results from laboratory dynamic modulus tests found that Hot Laid 3 (HL3) dynamic modulus is an exponential function of the test temperature when loading frequency is constant, and that the HL3 dynamic modulus is a non-linear function of the loading frequency when the test temperature is constant. Results from field controlled wheel load tests found that HL3 asphalt longitudinal strain is an exponential function of asphalt mid-depth temperature when the truck speed and wheel loading are constant. This indicated that the laboratory measured dynamic modulus is inversely proportional to the field measured asphalt longitudinal strain. Results from MichPave finite element program demonstrated that a good agreement between field measured asphalt longitudinal strain and MichPave prediction exists when field represented dynamic modulus is used as HMA properties. Results from environmental monitoring found that soil moisture content and subgrade resilient modulus changes in the pavement structure have a strong correlation and can be divided into three distinct Seasonal Zones. Temperature data showed that the pavement structure went through several freeze-thaw cycles during the winter months. Daily asphalt longitudinal strain fluctuations were found to be correlated with daily temperature changes and asphalt longitudinal strain fluctuations as high as 650m/m were recorded. The accumulation of irrecoverable asphalt longitudinal strain was observed during spring and summer months and irrecoverable asphalt longitudinal strain as high as 2338m/m was recorded.

There is a growing interest for the use of mechanistic procedures and analytical methods in the design and evaluation of pavement structure rather than empirical design procedures. The mechanistic procedures rely on predicting pavement response under traffic and environmental loading (i.e., stress, strain, and deflection) and relating these responses to pavement field performance. A research program has been developed at the Center for Pavement and Transportation Technology (CPATT) test track to investigate the impact of traffic and environmental parameters on flexible pavement response. This unique facility, located in a climate with seasonal freeze/thaw events, is equipped with an internet accessible data acquisition system capable of reading and recording sensors using a high sampling rate. A series of controlled loading tests were performed to investigate pavement dynamic response due to various loading configurations. Environmental factors and pavement performance were monitored over a two-year period. Analyses were performed using the two dimensional program MichPave to predict pavement responses. The dynamic modulus test was chosen to determine viscoelastic properties of Hot Mix Asphalt (HMA) material. A three-step procedure was implemented to simplify the incorporation of laboratory determined viscoelastic properties of HMA into the finite element (FE) model. The FE model predictions were compared with field measured pavement response. Field test results showed that pavement fully recovers after each wheel pass. Wheel wander and asphalt mid-depth temperature changes were found to have significant impact on asphalt longitudinal strain. Wheel wander of 16 cm reduced asphalt longitudinal strains by 36 percent and daily temperature fluctuations can double the asphalt longitudinal strain. Results from laboratory dynamic modulus tests found that Hot Laid 3 (HL3) dynamic modulus is an exponential function of the test temperature when loading frequency is constant, and that the HL3 dynamic modulus is a non-linear function of the loading frequency when the test temperature is constant. Results from field controlled wheel load tests found that HL3 asphalt longitudinal strain is an exponential function of asphalt mid-depth temperature when the truck speed and wheel loading are constant. This indicated that the laboratory measured dynamic modulus is inversely proportional to the field measured asphalt longitudinal strain. Results from MichPave finite element program demonstrated that a good agreement between field measured asphalt longitudinal strain and MichPave prediction exists when field represented dynamic modulus is used as HMA properties. Results from environmental monitoring found that soil moisture content and subgrade resilient modulus changes in the pavement structure have a strong correlation and can be divided into three distinct Seasonal Zones. Temperature data showed that the pavement structure went through several freeze-thaw cycles during the winter months. Daily asphalt longitudinal strain fluctuations were found to be correlated with daily temperature changes and asphalt longitudinal strain fluctuations as high as 650m/m were recorded. The accumulation of irrecoverable asphalt longitudinal strain was observed during spring and summer months and irrecoverable asphalt longitudinal strain as high as 2338m/m was recorded.

Cost effective maintenance of pavement sections requires timely preventive maintenance and planned rehabilitation treatments. Knowledge of the increase in condition due to application of treatment and the loss of condition after treatment are essential when deciding the maintenance and rehabilitation treatments. Any error in formulating these values can cause significant changes in recommendations provided. Many researchers have developed pavement performance prediction models; however, less research has been done on the impact of treatment actions on the condition of a pavement section after treatments. The objective of the research is to develop equations, using deterministic empirical method, that predict the increase in pavement condition and rate of decrease in pavement condition after treatment actions with respect to pavement condition just before the treatment. The equations are developed for different treatments and different functional class, and surface type combination to quantify the impact of the treatment for the use in pavement management system. These equations can be used to quantify the effects of different treatments for the use in pavement management system. Numerical illustration is presented using the data from the Metropolitan Transportation Commission-Pavement Management System software developed by the Metropolitan Transportation Commission (MTC) located in Oakland, California. A relation is observed between increase in pavement condition and pavement condition just before treatment for different treatments and different functional class and surface type combination. Hence the equations to determine the trend in increase in pavement condition for different treatments and different functional class and surface type combination are developed. For rate of decrease in pavement condition, due to large variability in the data the loss of pavement condition per year could not be related to pavement condition just before treatment. Hence the equations to determine the trend in loss in pavement condition after treatment could not be developed. The developed equations can be efficiently used to predict increase in pavement condition due to application of the treatment and the loss of pavement condition after treatment.

The research presented in this thesis covers the development, calibration and verification of two thin surfaced unbound granular pavement models: one model to predict the response of a pavement to loading by the monotonic application of a single load event (Response model) and the other model to predict the accumulation of permanent deformation of the pavement when it is subjected to a large number of load applications (Performance model). The response model was developed using the finite element method and used an anisotropic stress dependent stiffness model to represent the granular and subgrade materials. The models were verified with an extensive set of stress, strain and surface deflection measurements collected at the CAPTIF facility. The calibrated models were able to predict the subsurface response of the pavement to a range of dual tyre and FWD load levels (23-72 kN). It was found that the measured stress and strain response of the pavement was different under the two loading mechanisms. It was also found that a particular response at a point in the pavement was linear with respect to load. The performance model was based on similarities observed in the performance of granular materials in both laboratory and full-scale experiments. When the specimen or pavement was showing a steady state response, it was found that the rate of accumulation of permanent deformation was related to the resilient strain. This relationship was then used to predict the deformation of CAPTIF pavements based on the outputs from the response model. The application of laboratory derived models required the use of shift functions to be able to be successfully used in replicating field measurements, this was expected given the differences in boundary conditions and loading mechanisms for the laboratory and field systems.

Neste trabalho são estudados os principais parâmetros do projeto estrutural de pavimentos rodoviários e de pisos industriais de concreto. Faz-se um levantamento bibliográfico, apresentando as características estruturais de diversos tipos de pavimentos rígidos. São discutidas as ações diretas e as indiretas em pavimentos de concreto e analisadas as formas de consideração das forças aplicadas. São apresentados modelos para representação da fundação, do pavimento e dos materiais. É feito um resumo da teoria de Westergaard, para determinação de tensões devidas ao tráfego, e da teoria de Bradbury, para determinação de tensões devidas ao empenamento. O comportamento dos pavimentos rígidos sob diversas configurações de carregamento são analisadas com auxílio de software com base no método dos elementos finitos. Apresentam-se os métodos indicados pelo DNER para determinação da espessura de pavimentos de concreto simples. São discutidas equações para determinação da área de aço para combate à retração e desenvolvido um procedimento para dimensionamento da armadura de flexão, com base na revisão da NB-1. São analisados os mecanismos de formação de fissuras e a importância das juntas. São apresentadas equações para dimensionamento das barras de transferência e das barras de ligação e analisada a influência da eficiência da junta nos esforços das placas. São desenvolvidos exemplos numéricos sobre dimensionamento de pavimentos de concreto simples e de concreto armado, e sobre detalhamento das juntas / In this work are studied the main parameters of the structural project of concrete highway and industrial pavements. A bibliographical rising is made presenting the structural characteristics of several types of rigid pavements. Direct and indirect actions in the concrete pavements are discussed and the procedures of load consideration are analyzed. Models for represent the foundation, the pavement and the materials are showed. A summary of Westergaard’s theory for determination of stresses owed to the traffic and of Bradbury’s theory for determination of stresses owed to the curling is presented. The behavior of rigid pavements under several loading configurations is analyzed, with a software based on finite elements method. The thickness design methods for concrete pavement indicated by DNER are presented and discussed. The equation for determination of shrinkage reinforcement is showed and a procedure for design of positive steel is developed, based on the brazilian code. The cracking mechanism and the importance of joints are analyzed. Design equations for dowels and tie bars are studied. Numeric design examples are developed for plain concrete pavements, for reinforced concrete pavement, and for design of the joints