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The continuous investigation into the mechanical properties and rehabilitation management of existing pavements is vital for the sustainability and efficiency of transportation systems. The Mississippi Department of Transportation (MDOT) database, containing over 40 million records, necessitates modernized decision-making models that align with current design methods and materials. In collaboration with the University of Mississippi, MDOT's pavement management program aimed to update outdated Markov transition matrices with advanced Artificial Neural Networks (ANNs). This four-year project focuses on dynamic sequential ANNs to develop performance prediction models for flexible, rigid, and composite pavements, utilizing extensive distress data. Initial results for flexible pavements showed promising outcomes, with robust statistical accuracy measures for rigid pavements (JCP and CRCP) and composite pavements, although further data and calibration are recommended. The developed models, accessible through a user-friendly interface, are expected to improve the prioritization of maintenance and rehabilitation resources, achieving significant time and cost savings while enhancing the overall efficiency of MDOT's pavement management practices.

The objectives of this research were to 1) provide the first step for the implementation of ME design for flexible pavements in Florida by comparing the 93 Method to the ME Design Method, 2) predict distresses to observed distresses of the PMED Version 2.6, and 3) provide recommendations for Florida-specific input parameters for the PMED Version 2.6.

Asphalt pavement thickness design, for both new and overlay scenarios, has been evolving since the 1960’s from empirical to mechanistic-empirical design frameworks. Regardless of the design methodology, the fundamental goal of thickness design has been to determine the optimum cross-section to achieve the desired performance under the prevailing conditions (i.e., traffic, climate and materials). Central to that effort has been the calibration of design systems to accurately predict pavement deterioration over time. While calibration can be effective in developing more accurate predictions and, therefore, optimizing cross-sections, most design systems do not have a maximum thickness built into the procedure, which can yield unreasonably thick cross-sections. Figure 1.1 shows a simple example, developed with the AASHTO 1993 Design Guide, where the Asphalt Concrete (AC) layer thickness is plotted against the design traffic, expressed in terms of Equivalent Single Axle Loads (ESALs). Clearly, the AC layer thickness increases indefinitely with traffic to overly thick sections that are likely overdesigned and impractical to build. This problem also exists with mechanistic-empirical design approaches such as the Mechanistic-Empirical Pavement Design Guide (AASHTO, 2008). Each design approach is simply a set of mechanistic and empirical equations that yield recommended design thicknesses given a set of material, structural, traffic, and climate inputs and leaves it to the designer, or written policy, to decide when it is sufficiently thick.

This research project conducted a local verification to assess the accuracy of globally calibrated Pavement ME Design distress and smoothness models for asphalt pavements in Alabama. Pavement sections included LTPP test sections in Alabama and neighboring states, as well as sections tested at the NCAT Test Track. Results showed significant bias in the rutting prediction model for both LTPP and NCAT Test Track sections. The PMED software underpredicted fatigue cracking percentages for general LTPP pavement sections while overpredicting fatigue cracking percentages for NCAT Test Track pavement sections. The IRI prediction model also exhibited significant bias, indicating higher predicted values than measured values. Based on the findings, local calibration of the PMED performance models is essential for accurate predictions under Alabama conditions. Other implementation activities may include validation with independent datasets and training on Pavement ME Design. This project highlights the importance of local verification and calibration to improve prediction accuracy, ensuring more reliable and cost-effective pavement structures.

Objective: This research presents a novel multi-criteria methodology that allows evaluating two asphalt materials used in the paving sector, aiming to provide guidelines for selecting a material under a sustainable profile. This methodological tool allows evaluating characteristics and indicators associated with the behavior of an asphalt mixture in an integrated and consistent way as well as with environmental impact. Methodology: A sustainability parameter associated with the study of two materials from the paving sector was obtained. The main characteristics of a hot asphalt mixture and a cold mixture under the same contour conditions were evaluated. Regarding the multi-criteria model, the concept of decision theory was taken, supported by the MIVES methodology and the utility function, thus allowing to evaluate and compare the indicators proposed for this analysis case. Results: The sustainability index was obtained for the two materials studied. The cold asphalt mixture obtained a value of 0,76, representing an overall better performance in the three axes analyzed (environmental, economic, and operation). On the other hand, the hot mixture obtained an index of 0,57, a value inherent to a less positive response than the cold mixture. Conclusions: The developed methodology allowed for the incorporation of variables and indicators of different units of measurement and diverse nature. Obtaining a sustainability index in asphalt materials represents a significant advance in the application of multi-criteria methodologies., Objetivo: Esta investigación presenta una novedosa metodología multicriterio que permite evaluar dos materiales asfálticos utilizados en el sector de la pavimentación, en aras de aportar directrices al momento de seleccionar un material bajo un perfil sostenible. Esta herramienta metodológica permite evaluar características e indicadores asociados al comportamiento de una mezcla asfáltica de forma integrada, consistente y con impacto medioambiental. Metodología: Se obtuvo un parámetro de sostenibilidad asociado al estudio de dos materiales del sector de la pavimentación. Se evaluaron las principales características de una mezcla asfáltica en caliente y una mezcla fría bajo las mismas condiciones de contorno. Con respecto al modelo multicriterio, se tomó el concepto de teoría de la decisión, con apoyo de la metodología MIVES y la función de utilidad, permitiendo evaluar y comparar los indicadores propuestos para este caso de análisis. Resultados: Se obtuvo el índice de sostenibilidad para los dos materiales estudiados. La mezcla asfáltica fría obtuvo un valor de 0,76, representando de forma global un mejor desempeño en los tres ejes analizados (medioambiental, económico y de operación). Por otro lado, la mezcla en caliente obtuvo un índice de 0,57, valor inherente a una respuesta menos positiva que la mezcla fría. Conclusiones: La metodología desarrollada permitió incorporar variables e indicadores con unidades de medición distintas y de naturaleza diversa. La obtención de un índice de sostenibilidad en materiales asfálticos supone un avance significativo en la aplicación de metodologías multicriterio.

This study aims to compare the structural contribution of the granular base layer stabilized with type I Portland cement versus CSS-1H cationic asphalt emulsion on roads of the Micaela Bastidas housing complex, whose area corresponds to Enlace I, II, III, IV Stage and in UPIS Villa Hermosa, Veintiséis de Octubre district, department of Piura, province of Piura. As part of the analysis, laboratory tests were carried out on the granular material extracted from the Bastian quarry, in order to obtain the characteristics of the base material. In such a way, that for the comparative evaluation of the structural contribution of the granular base, the calculation of the design for flexible pavements was executed according to the AASHTO 93 method; according to the road manual section soils and pavements, stabilized with Portland cement type I, cationic asphalt emulsion CSS-1H and without stabilization. The results obtained indicated that according to the estimated dosages at 3%, 5% and 7% of cement addition and the asphalt emulsion improves the conditions of the granular base material. In conclusion, according to the evaluation of the structural contribution, type I Portland cement is the stabilizing agent with the best behavior, even in very low dosages, which translates into pavements of competent thicknesses in construction practice, Este estudio tiene como objetivo comparar el aporte estructural de la capa base granular estabilizada con cemento Portland tipo I versus emulsión asfáltica catiónica CSS-1H en vías del conjunto habitacional Micaela Bastidas, cuya área corresponde a Enlace I, II, III, IV Etapa y en la UPIS Villa Hermosa, distrito Veintiséis de Octubre del departamento de Piura, provincia de Piura. Como parte del análisis se realizaron ensayos de laboratorio al material granular extraídos de la cantera Bastian, con el fin de obtener las características del material base. De tal manera, que para la evaluación comparativa del aporte estructural de la base granular se ejecutó el cálculo del diseño para pavimentos flexibles de acuerdo con el método AASHTO 93; según el manual de carreteras sección suelos y pavimentos, estabilizados con cemento Portland tipo I, emulsión asfáltica catiónica de rotura lenta CSS-1H y sin estabilizar. Los resultados obtenidos indicaron que según las dosificaciones estimadas al 3%, 5% y 7% de adición de cemento y la emulsión asfáltica mejora las condiciones del material base granular. En conclusión, la evaluación del aporte estructural el cemento Portland tipo I es el agente estabilizador de mejor comportamiento, incluso en dosificaciones muy bajas, lo cual se traduce en pavimentos de espesores competentes en la práctica constructiva

This research project is the first step toward Mechanistic-Empirical (ME) Design implementation for flexible pavements in Florida. The Florida Department of Transportation currently uses the American Association of State Highway and Transportation Officials 93 Method for flexible pavement design and is considering changing to the Pavement ME Design Method (PMED) in the future. Before implementation, the PMED must undergo a series of analyses, calibrations, and validation. First, the research team performed PMED sensitivity analysis to determine which failure models are most relevant to Florida using global inputs. After that, the research team evaluated pavement distresses using the Florida-specific parameters. Lastly, the research team developed a work plan that covered the locally based steps for the PMED calibrations and implementation for Florida. Version 2.6 or higher should be used with local calibration of the ME Design Method for flexible pavements. The Version 2.6 and higher versions include an improved top-down cracking model. The omission of the top-down cracking model in the previous versions was the primary reason for delaying implementation of the PMED for flexible pavements in Florida in past years. Implementation is recommended to be delayed until the roadmap Phases 1 and 2 are completed.

It is well established that both traffic-related loading and environmental conditions influence the structural behaviour of pavements. Pavement design methods aim to consider the effect of traffic loading and environmental variables on pavement structure, foresee their changes during the lifetime of the pavement and predict the resulting distresses and pavement life. Newer models are required to further advance the development of pavement design methods. Validations using reliable and representative data are required prior to incorporating these models in pavement design methods. The impact of environmental factors such as temperature, moisture content and freeze-thaw cycles on pavement behaviour have been examined in this doctoral thesis. Furthermore, the impact of increased loading by new long heavy vehicles on low-volume roads subjected to large variations of the environmental conditions has been investigated. The findings presented in this thesis have been based on field data collected on roads that have been and currently are in day-to-day operation. The collected data on mechanical response, temperature, moisture and frost was used to validate models on mechanical behaviour and thermal behaviour, as well as the effect of their interaction in pavement structures. The models developed and validated in this study are aimed to be integrated into a new mechanistic-empirical pavement design framework that is currently under development in Sweden. The work done for this thesis is presented hereby in the form of 5 papers and a short summary part. This thesis is a continuation of a licentiate thesis previously published at KTH Royal Institute of Technology. Part of the material published in the licentiate thesis has been included in this doctoral thesis., Det är väl känt att både belastning från trafik och klimat påverkar vägars strukturella beteende. Strukturella dimensioneringsmetoder för vägar tar hänsyn till båda dessa belastningar och förutser deras inverkan på nedbrytningsförloppet under dimensioneringsperioden. Nya metoder och modeller är under utveckling som syftar till att utöka och förbättra förutsägelserna av vägars tillståndsförändringar och därmed nedbrytningsprocessen. Dessa modeller behöver valideras mot uppmätta data innan de börjar användas i allmänna dimensioneringsprogram. Denna doktorsavhandling undersöker påverkan av klimatfaktorer så som temperatur, fukt och frys-tö cyklar på vägars strukturella beteende. Dessutom har det undersökts hur långa och tungt lastade fordon påverkar tunna vägkonstruktioner vid olika klimatförhållanden. Avhandlingens slutsatser baseras på jämförelser av fullskaliga försök med tunga fordon som används på vägnätet i dag med beräkningar. Insamlad last- och töjningsdata från sensorer i vägkroppen som belastas med tung trafik samt vägtemperatur, fukt och frost har använts för att validera modeller för att beräkna den uppmätta mekanistiska samt termiska responsen i vägar. De modeller som har utvecklas och validerats har inkluderats i en ny mekanistisk – empirisk vägdimensioneringsmetodik som är under utveckling i Sverige. Resultaten presenteras här i fem artiklar samt i en kort sammanfattande del. Doktorsavhandlingen är en fortsättning av en Licentiatavhandling som tidigare har publicerats vid KTH. Delar av det arbetet är även inkluderat i denna avhandling.

Pavement performance models play a vital role in any pavement management system. The Regional Government of Biscay (RGB) (Spain) manages a 1200 km road network and conducts pavement data collections, including the International Roughness Index (IRI) values. The aim of the paper is to develop an IRI performance model for two-lane roads with flexible pavement until the first maintenance and/or rehabilitation activity is performed. Due to the huge amount of available information, a deterministic model was selected. A literature review of deterministic models showed that, apart from age and traffic volumes, the pavement structure is a key factor. Therefore, it was decided to analyze the only road stretches whose entire pavement section was known (surface layer + base + subbase). Various variables related to age, traffic volumes and employed materials were introduced as possible factors. The multiple linear regression model with the highest coefficient of determination and all the variables significant included the real pavement age, the cumulated heavy traffic and the total thickness of bituminous layers. As the material employed in the surface layer could affect roughness progression, a qualitative variable was introduced to consider various surface materials. The model improved its accuracy, indicating that the surface layer material is also an influencing factor on IRI evolution.

The use of bases treated with hydraulic binders or asphalt binders has become a common solution in the construction of pavement bases or sub-bases due to the need to achieve high performance, and also because of the increment of the repetitions and magnitudes of loads in transportation. The treatment with additives provides greater resistance and behavior to the pavement layers over time. A granular material was selected with the purpose of evaluating the effectiveness of one of these treatments. This material did not meet the requirements of a road subbase because of its high plasticity. A cationic asphalt emulsion was incorporated to this granular material in order to check the variations that this treatment could experience regarding its resistance in the laboratory. Finally, good results were obtained with this treatment. An increase in resistance to CBR after immersion and conserved resistance were observed. The modifications produced after the treatments, are also shown by comparing a conventional flexible structure and a structure with a stabilized sub-base layer with an emulsion instead of a non-agglomerate traditional subbase, using an empirical-mechanistic procedure of AASTHO Design Guide., La utilización de bases tratadas con conglomerantes hidráulicos o ligantes asfálticos, se ha convertido en una solución habitual en la construcción de bases o subbases de pavimentos, por la necesidad de alcanzar altas prestaciones, debido al incremento de las repeticiones y magnitudes de las cargas del transporte automotor. El tratamiento con aditivos proporciona a las capas del pavimento una mayor resistencia y comportamiento en el tiempo. Con el propósito de evaluar la efectividad de uno de estos tratamientos, se seleccionó un material granular que no cumple con las exigencias de una subbase de carreteras debido a su alta plasticidad, para incorporarle una emulsión asfáltica catiónica y comprobar la variación que experimenta en sus prestaciones, en el laboratorio. Con el tratamiento se han alcanzado buenos resultados, incrementando la resistencia a CBR tras inmersión y en la resistencia conservada. Se muestran también las modificaciones que trae el uso de estos tratamientos en el comportamiento de una estructura de pavimento en la que se ha concebido una capa de subbase estabilizada con emulsión, en lugar de una subbase tradicional no aglomerada, utilizando para ello el procedimiento empírico-mecanicista de la Guía de Diseño AASTHO (American Association of State Highway and Transportation Officials).

Tato diplomová práce se zabývá využitím upravených vysokopecních strusek v recyklovaných stmelených směsích konstrukčních vrstev pozemních komunikací. Teoretická část shrnuje poznatky o technologii recyklace za studena a věnuje se alternativním zdrojům hydraulických pojiv v podobě vysokopecních strusek. V experimentální části je popsána výroba jednotlivých stmelených směsí včetně vyhotovení zkušebních těles a postupy provedených laboratorních zkoušek. V závěru jsou shrnuty a porovnány vyhodnocené výsledky experimentálních zkoušek., This master thesis deals with the use of treated blast furnace slags in cold recycled stabilized mixtures for structural pavement layers. The theoretical part summarizes the existing knowledge about cold recycling technology and deals with alternative sources of hydraulic binders in the form of blast furnace slags. The experimentalsection describes the production of individual bonded mixtures,including the preparation of test specimens and performed laboratory test procedures. In conclusion, the evaluated results of experimental tests are summarized and compared., Dopravní fakulta Jana Pernera, Uchazeč prezentoval komisi hlavní výsledky a závěry své diplomové práce. Po prezentaci diplomové práce zodpověděl dotazy vedoucího a připomínky oponenta diplomové práce (uvedeny v posudcích práce). V diskusi o diplomové práci podrobně zodpověděl všechny dotazy členů komise., Dokončená práce s úspěšnou obhajobou

The load capacity of goods vehicles is a critical variable in calculating transport costs. In Europe, the Council Directive 96/53/EC establishes the maximum weight and dimensions of goods vehicles in international traffic but also allows that any Member State authorises the movement of vehicles that fail to comply with these weights and dimensions within its territory. For this reason, some countries have used this power to introduce internal regulations regarding the maximum transport capacity. A case of particular interest discussed in this article is the vehicle with five axles (two tractor axles and 3-axle semitrailer), which is only allowed a maximum weight of 40 t by the Directive above. While some countries allow a maximum weight of 44 t when circulating within their territories, the limitation in Spain has been established by the Council Directive 96/53/EC of 25 July 1996 40 t, although this restriction is often discussed by the different agents related to the transport of goods by road. Therefore, this paper analyses the effect of T2S3 vehicles loaded with 42 t and 44 t on sections of flexible and semi-rigid pavements of the Spanish road network, to provide information about the impacts of the modification of the regulations on capacity., Peer Reviewed, Postprint (published version)

[Abstract] The structural failure of a flexible pavement occurs when the accumulated fatigue damage produced by all the vehicles that have passed over each section exceeds a certain threshold. For this reason, the service life of pavement can be predicted in terms of the damage caused by the passage of a single standard axle and the expected evolution of traffic intensity (measured in equivalent standard axles) over time. In turn, the damage caused by the passage of an axle depends on the vertical load exerted by the wheels on the pavement surface, as given by the technical standard in application, and the depths and mechanical characteristics of the layers that compose the pavement section. In all standards currently in application, the unevenness of the road surface is disregarded. Therefore, no dynamic effects are taken into consideration and the vertical load is simply given in terms of the static weight carried by the standard axle. However, it is obvious that the road profile deteriorates over time, and it has been shown that the increase in the pavement roughness, when considered, gives rise to important dynamic effects that may lead to a dramatic fall in the expected structural service life. In this paper, we present a mathematical formulation for the fatigue analysis of flexible pavements that includes the effects of dynamic axle loading. A pavement deterioration model simulates the sustained growth of the IRI (International Roughness Index) over time. Time is discretized in successive time steps. For each time step, a road surface generation model provides a profile that renders the adequate value of the IRI. A QHV (Quarter Heavy Vehicle) model provides the dynamic amplification function for the loads exerted on the road surface along a virtual ride. This function is conveniently averaged, what gives the value of the so-called effective dynamic load amplification factor (DLA); this is the ratio between the effective dynamic loading and the static loading a

Diplomová práce je zaměřena na analýzu možností využití georadaru pro detekci konstrukčních vrstev netuhých vozovek na pozemních komunikacích. V teoretické části jsou popsány základní vlastnosti, metody práce a nastavení GPR. V praktické části se práce věnuje sérii experimentálních měření na laboratorních vzorcích, testovacím úseku a v neposlední řádě měření na vybraném úseku silnice II/322 Dašice. Součástí diplomové práce je vyhodnocení jednotlivých měření v laboratoři VVCD, stanovení rychlosti šíření a relativní permitivity na materiálech v IBC kontejnerech. Praktická část je ukončena měřením v in-situ, vyhodnocením získaných dat a následné porovnání s převzatými daty od Správy a údržby silnic Pardubického kraje. Na základě rešerše z literatury a vlastních zkušeností z měření byla vypracována analýza možností využití GPR pro detekci konstrukčních vrstev netuhých vozovek pozemních komunikací., The diploma thesis is focused on the analysis of the possibilities of georadar utilization for detection of structural layers of flexible pavements on roads. The work focuses on the basic features. In the practical part, the thesis deals with a series of experimental measurements on laboratory samples, the test section on a selected section of road. The aim of the practical part is to evaluate individual measurements in the VVCD laboratory, to determine the rate of propagation velocity and relative permitivity of materials in IBC containers. Practical part is completed by in-situ measurement, evaluation of acquired data and subsequent comparison with taken over data. Based on a literature search and own measurement experience, the analysis of the possibilities of using GPR for the detection of structural layers of flexible pavements was developer., Dopravní fakulta Jana Pernera, Uchazeč prezentoval komisi hlavní výsledky a závěry své diplomové práce. Po prezentaci diplomové práce zodpověděl dotazy vedoucího a připomínky oponenta diplomové práce (uvedeny v posudcích práce). V diskusi o diplomové práci podrobně zodpověděl všechny dotazy členů komise.

The main objective of this project consists in estimate a value of wheel wander representative of Costa Rican roadways, which could be used for pavements design and testing. In order to achieve the objective, wheel wander was measured and computed in 6 different stations with similar characteristics located in national routes from the Great Metropolitan Area of Costa Rica. Wheel wander is the scatter of vehicles along the length of the lane. Drivers usually follow a normal distribution pattern. In the wheel paths that most drivers follow, traffic load will be higher causing rutting in the pavement. Therefore, in roadways where wheel wander is high, the traffic load is distributed along the lane width, increasing the design life. For each station only the outer lane, the closest to the camera, was used. These stations are located in National Route 3, National Route 2, National Route 202, National Route 32, National Route 39 and National Route 108. These routes were chosen because of their high truck traffic volume. In each station, a camera was placed roadside. Also lines were drawn covering more than the half of the lane cross section. The position of both heavy and light vehicles was measured. Standard deviation and confidence interval for variance equations were used to determine the wheel wander. Results show that the mean and 95% confidence interval of wheel wander is drastically higher that the value of 10 cm used by the LanammeUCR for accelerated pavements testing., El objetivo del proyecto consiste en determinar un valor de desplazamiento lateral que sea representativo para carreteras urbanas de Costa Rica, que pueda ser utilizado para el diseño y simulación del deterioro de pavimentos. Para esto se realizó un cálculo del desplazamiento lateral en 6 diferentes estaciones ubicadas en rutas nacionales dentro del Gran Área Metropolitana de Costa Rica con características similares.El desplazamiento lateral es la dispersión de los vehículos en el ancho del carril, estos usualmente tienen una distribución de tipo normal. En los puntos en los que transitan más vehículos hay mayor deterioro del pavimento, por lo tanto, entre mayor es el desplazamiento lateral los vehículos se distribuyen más en el carril y el daño al pavimento es menor.Las estaciones donde se realizaron las mediciones se ubican en la Ruta Nacional 3, Ruta Nacional 2, Ruta Nacional 202, Ruta Nacional 32, Ruta Nacional 39 y Ruta Nacional 108. Los cuales fueron seleccionados por tener un alto porcentaje de vehículos pesados. En cada estación se colocó una cámara y se trazaron líneas para medir la posición transversal en el carril de los vehículos que transitaban en el sitio, tanto livianos y pesados.Se calculó el desplazamiento lateral utilizando la ecuación de la desviación estándar de los datos de la posición de los vehículos, y el intervalo de confianza utilizando la ecuación del intervalo de confianza de la desviación estándar. Los resultados muestran el valor obtenido es significativamente mayor que el valor de desplazamiento lateral de 10 cm utilizado por el LanammeUCR para los ensayos de simulación del deterioro de pavimentos.

The aim of this research was to evaluate the mechanical behavior of natural asphalt by making samples at ambient temperature. It was made a material characterization testing, using quantitative extraction of bitumen to know the asphalt content in the material. Then, it was proceeded to fabricate samples with pure natural asphalt in the gyratory compactor, and finally, samples were assayed by indirect tensile strength test in dry and wet conditions to know the viability of its use in tertiary roads without being subjected to high temperatures in manufacturing and mixing. The main result is evidence that the specimens fabricated at room temperature have very low resistance, so it is necessary to test the addition of stone aggregates at the same temperature and asphalt emulsions., El objetivo de esta investigación fue evaluar el comportamiento mecánico del asfalto natural por medio de la fabricación de muestras a temperatura ambiente. En primera instancia se realizó la caracterización del material con el ensayo de extracción cuantitativa del asfalto y así conocer el contenido de asfalto presente en el material, luego se procedió a fabricar muestras con la asfaltita pura en el compactador giratorio y por último se ejecutó sobre éstas el ensayo de Resistencia a Tracción Indirecta, RTI, en estado seco y en estado húmedo, para así conocer la viabilidad de su uso en vías terciarias, sin tener que someterla a altas temperaturas de fabricación y mezclado. Como resultado principal se evidencia que las probetas fabricadas a temperatura ambiente presentan resistencias muy bajas, por lo cual es necesario probar con la adición de agregados pétreos a la misma temperatura y emulsiones asfálticas.

The need for pavement preservation is widely recognized by transportation agencies. Over the past few years, the Maryland State Highway Administration (MDSHA) has made significant advancements in developing guidelines for pavement preservation in Maryland. The Pavement and Geotechnical Division (PAGD) within MDSHA has developed a pavement preservation guide that will assist in determining the "right fix for the right road at the right time" when used in conjunction with network-level and project-specific data. This guide was developed based on review of state-of-the-practice literature pertaining to pavement preservation, past experiences and the resource base of MDSHA pavement engineers. Step-by-step instructions on determining treatment options were developed through the use of flow charts, decision trees and treatment tables. At the end of the step-by-step process, there will be many viable treatment options available for consideration. In addition, various treatment options are also defined, along with information regarding treatment cost, advantages, disadvantages and other items. These options, along with the use of good judgment, common sense and research of current best practices help facilitate good decision-making. The ultimate selection of a preservation strategy by the District is based on the most cost-effective engineering design considering cost, practicality of construction, and benefit in terms of life extension. This paper presents an overview of the guide as of December 2014. Updates are made to this guide as new paving technologies emerge, and as feedback about performance of treatments is available. Efforts are also underway to integrate this guide into the pavement management optimization analysis.

Presently work is exposed a methodology that allows to carry out an intervention proposal with regard to the rehabilitation of the pavement, as well as the determination of the reinforcement thickness, starting from the parameters of the deflection bowl.They are obtained, on the base of the structures regulated in the norm of SATCC, 2001 (Southern Africa Transport and Communications Commission), and the use of the computation program JULEA, the corresponding answer surfaces starting from the indexes of the deflection, what allows to formulate the mathematical expressions to estimate the module and the condition of each one of the layers of the structure of the pavement and the equation for the calculation of the thickness reinforcement.The results of the methodology are shown applied in a study case, where they are carried out confirmations of the deflection with the Benkelman beam and the use of the Falling Weight Deflectometer (FWD), being verified the validity of the proposed procedure that increase the speed in the obtaining of the results of the diagnosis and rehabilitation solutions., Se expone una propuesta metodológica para la evaluación de pavimentos flexibles, de interés en los proyectos de rehabilitación de carreteras; En esa dirección se muestra un procedimiento para el diagnóstico y propuesta de solución de rehabilitación del pavimento, a partir de los parámetros del cuenco de deflexión.Se obtienen, sobre la base de las estructuras reglamentadas en la norma SATCC, 2001 (Southern Africa Transport and Communications Commission), y el uso del programa de computación JULEA las correspondientes superficies de respuesta a partir de los índices del cuenco de deflexión, lo que permite formular las expresiones matemáticas para estimar el módulo de la subrasante, la condición de cada una de las capas de la estructura del pavimento y la ecuación para el cálculo del espesor de refuerzo.Se muestran los resultados de la metodología aplicada en un caso de estudio, donde se realizan mediciones del cuenco de deflexión con la viga Benkelman y el uso del deflectómetro de impacto (FWD por sus siglas en inglés) verificándose la validez del procedimiento propuesto el cual incrementa la rapidez en la obtención de los resultados del diagnóstico y soluciones de rehabilitación.Palabras clave: pavimentos flexibles, cuenco de deflexión, rehabilitación de carreteras.

With over 1.5 billion square feet of airfield pavements in its portfolio, the U.S. Air Force has a vested financial interest in refining its design, maintenance, and inspection criteria to increase the efficiency of its investment in its infrastructure. As part of its strategic pavement assessment, the Air Force is currently moving to adopt the new design method (CBR-Beta) developed by the U.S. Army Corps of Engineers (USACE) on the basis that the new methodology more accurately represents the performance of flexible airfield pavements, particularly with newer, heavier aircraft. Supporting this adoption of the new method, this research primarily focused on evaluating the current set of equivalency factors in use by the Air Force and the USACE using a meta-analysis approach. Building on this initial success, the research shifted to analyzing the life-cycle costs of the various flexible pavement design methods relative to a common design standard to eliminate the problems associated with comparing the methods each with its own assumptions and processes. Looking to further refine the predictability of the CBR-Beta method, the research analyzed the formulation of O.K. Frohlich's concentration factor. Additionally, the research assessed the possibility of expanding the empirical airfield data set with highway testing data. Ultimately, this research led to recommending new equivalency factors for stabilized layers, a new two-layer concentration factors model, an extension to CBR-Beta for highway pavements, and provides evidence to reformulate Beta as a stress-derived variable as opposed to failure-derived., The original document contains color images.

Textile Ceramic Technology (TCT) is a new material composed of ceramic units installed in a grid of steel wires. TCT application as a permeable pavement is expected to be a sustainable and aesthetic solution. In order to use TCT as a pavement, experimental research about the mechanical response of TCT placed on elastic foundations is required. The main aim of this paper is to provide the results of this experimental research. Different TCT types were tested in quasi-static and cyclic conditions. The paper presents also a numerical study and a real site application carried out to further evaluate the technology. Experimental, numerical and application results pointed out that TCT is sufficiently competent, from a mechanical point of view, to be used as a pavement for pedestrian and light traffic., Peer Reviewed, Postprint (author's final draft)

This study aims to introduce an alternative design model of unbound granular base course materials by utilising laboratory test results such as resilient modulus, permanent deformation and bearing capacity of base course materials. Current pavement designs mostly overlook all problematical behaviours of unbound granular base layers and consider only as a layer transferring traffic loads to underneath layers regardless on the unbound granular base course deteriorations. Based on the existing design protocols in Australia, there are only the design criteria of the horizontal tensile strains at the bottom of the asphalt layer and the vertical deformations occurring at the top of the subgrade. The actual performances of granular base course materials under traffic loads have been rarely accounted into the pavement design protocol. Currently, road activities are growing in terms of magnitude and frequency far beyond the past and causing the early road damages leading to major road maintenances. The study presents hypothetically the more ratiotial approach of the stress and strain distribution in a flexible pavement using the finite element method with sophisticated laboratory results. In this study, the effects of a traffic load and material attributes which they were generated when vehicle travels, hence stress and strain contributing between tires and characteristics of unbound granular pavement materials were investigated. Moreover, the alternative design model for unbound granular layers was defined in order to draw up the guideline and recommendation on the current pavement analysis and design. © Institution of Engineers Australia, 2012.

This study aims to introduce alternative design procedures for a flexible pavement base course by utilizing ultimate strength criteria with the sophisticated laboratory results of base course materials. Based on the design protocol, only the design criteria of the horizontal tension and the vertical compression occur at the bottom of the asphalt layer and at the top of the subgrade, respectively are employed. The real behavior of a base course under traffic loads has been rarely accounted into the pavement design protocol. Nowadays, traffic is growing in terms of magnitude and frequency far beyond the past causing premature deterioration in base course layers leading to major damage in pavements. The study presents theoretically a more suitable approach of stress and strain distributions in a flexible pavement using the finite element method. The effects of uniform design pressure and material attributes generated when a vehicle travels, namely the stress and strain contributions between tires and pavement layers, were investigated. Moreover, new design criteria for an unbound granular layer were defined as the ultimate strength design and the bearing capacity factor resulting from the application of the shallow foundation bearing capacity concept within the California Bearing Ratio (CBR) results.

A study was conducted on full-scale pavement test sections to assess geogrid/base reinforcement in flexible pavements representative of major highways. The experimental design, trafficking protocol, results and development of rutting models are reported herein. Accelerated trafficking was conducted with a heavy vehicle simulator on eight pavement test sections. Four test sections were reinforced with Geogrid placed at the base/subgrade interface; the other four were matching unreinforced (control) sections. Rut depths in the pavement surface as a function of applied traffic cycles were compared. Except for the thickest base and asphalt combination tested, the grid reinforcement provided benefit compared to unreinforced control sections as indicated by surface rut depth. (Four test sections reached ?failure? and four did not?traffic ceased at a set number of load cycles in these cases.) Empirical rutting models presented in NCHRP 1-37A, Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures (available from http://www.trb.org/mepdg/) were extended to account for the reinforcement. Mechanistic finite element models were calibrated using strains measured throughout the test sections. Predicted rut depths using this mechanistic-empirical approach were in reasonable agreement with measured values. For the pavement configurations of this study, Geogrid was predicted to increase the pavement life by 29 to 43 percent., The original document contains color images.

Field observations indicate that both traffic and thermal stresses affect top-down cracking performance of flexible pavements. Further evaluation of these observations will require the development and use of cracking models that can consider the effect of temperature. A rigorous analytical model was developed to assess the effect of thermal loading conditions and mixture properties on dissipated creep strain energy (DCSE) and cracking. Accumulation of DCSE in a mixture subjected to thermal stresses is much less straightforward than for load-induced stresses, and performance may be affected by the rheological aspects of the mixture other than creep. Appropriate equations were developed to calculate thermal stress development and DCSE accumulation for an asphalt mixture subjected to thermal loading cycles. Calculations performed with the resulting model showed that although top-down cracking performance in Florida was most strongly affected by traffic loading, thermal effects also affected performance. A combined system that incorporates the effect of both load- and temperature-induced damages on top-down cracking was developed and resulted in better correlation between predicted and observed top-down cracking performances., QC 20141022

A research project was initiated to identify surface roughness characteristics that influence heavy transport operatorsafety perception of the serviceability and rideability of road pavements with high levels of LWR in Victoria/Australia. The project involved conducting a subjective assessment survey to collect truck driversafety ratings of ride quality for a number of road test sections with varying roughness levels. The results of this study indicate that for the sections tested, the excitation of the low frequency vibration modes of the truck body including body roll have greater influence on truck driversafety perception of pavement rideability than the high frequency ones. However, vibrations resulting from exciting both the low and high frequency modes contribute to DWL of road pavements. The study also showed that climate and reactivity of the subgrade soil have great influence on roughness characteristics of pavement surfaces and their dynamic interaction with heavy vehicles.

The present study focused on the estimation of load and non-load shares of pavement maintenance and rehabilitation expenditures. The information provides the basis for the allocation of pavement-related expenditures in a highway cost allocation study. A comprehensive database was developed in the study, and an aggregate performance approach was used based on econometric models. This approach utilizes the marginal effect of traffic loading to quantify the load and non-load shares of pavement routine maintenance and rehabilitation expenditures. The study revealed that the share of pavement damage attributable to load and non-load factors depends on several factors such as the type of improvement (routine maintenance or rehabilitation), pavement type, and other variables. For routine maintenance, the load and non-load shares were found to be 25-75 for flexible pavements, 36-64 and 60-40 for Jointed Concrete Pavements (JCP) and Continuously Reinforced Concrete (CRC) pavements, and 30-70 for composite pavements. The load and non-load fractions of rehabilitation expenditures used to repair pavement damage were found to be 30-70 for flexible pavements, 80-20 for JCP, and 40-60 for composite pavements. It is expected that the results of this study will facilitate the apportionment of pavement routine maintenance and rehabilitation expenditures in a fair and equitable manner.

As part of the Dynamic Interaction Vehicle-INfrastructure Experiment (DIVINE) established in 1992, the U.S. Department of Transportation's Federal Highway Administration agreed to conduct pavement primary response testing to establish how a pavement, and particularly a flexible, asphaltic pavement responds to dynamic loading. The rational being that if the stress and strains generated by dynamically varying loads at critical points in the pavement structure can be measured, then this will help to confirm the benefits of road friendly suspensions. This research known as Element 2 of the DIVINE project is presented in this report and includes the design, conduct, and findings of the Federal Highway Administration's research. The research performed at the Federal Highway Administration's test road in McLean, VA was conducted on an instrumented pavement trafficked by instrumented vehicles. Instantaneous strains generated by the vehicle could be directly related to the instantaneous applied loads and thus an analysis of the primary response due to dynamic loading was undertaken. Furthermore, an artificial plywood bump placed on the test pavement was used to excite different suspension modes. Analysis and results of data are included in this report.

Experimental and analytical investigations were performed to evaluate the comparative performance of pavements with and without geosynthetic stabilization. This was accomplished by the testing of a total of 18 pavement sections which could be classified into four different types: one which was constructed without geosynthetics and which served as a control, and three which were stabilized with one of two geotextiles or a geogrid. The pavement sections were constructed to model a typical secondary road in Virginia which is constructed over a silty sand subgrade material. Loading of the pavement sections was accomplished through the use of a computer-controlled pneumatic system which delivered 80 lb/in2 (552 kPa) through a rigid plate at a frequency of approximately one-half Hertz. The resulting displacement of the pavement surface was monitored by an array of linear variable displacement transducers (LVDTs). The performance of each pavement section was evaluated using the American Association of State Highway and Transportation Officials (AASHTO) flexible pavement design method. Models based on empirical and mechanistic relationships were considered. A theoretical pavement section was also analyzed to assess the influence of the stiffness of a wearing course layer. An economic study was performed to assess the potential cost benefit of geosynthetic stabilization and recommendations have been made for additional research.

Civil Engineering and Geosciences

A pavement evaluation procedure is presented for evaluating conventional flexible airfield pavements that will fail in fewer than 100 coverages. The procedure utilizes deflection data obtained from a Falling Weight Deflectometer and the age of the pavement to predict the coverages of an F-4 aircraft to failure. Procedures for correcting temperature of the asphalt pavement layer and for predicting performance of other aircraft are presented.

Part I describes the pavement analysis program DEFPAV. The development of pavement models for two sections of road is described in detail; they predict the values of transient deflection and rut depth growth. The use of the program in analyzing the effect of surface temperature on transient deflections is described. An investigation of the effect of crack propagation through a bituminous surface layer is also reported. Part II describes a method of overlay thickness selection for flexible pavements. A rational selection of bituminous overlay may be made with the aid of a transient deflection measurement and a single computational procedure which is suitable for use on a modern programmable calculation. (Author)

Seven pairs of pavement with granular bases were tested under controlled conditions. One pavement in each pair contained fabric inclusions. An improved testing facility was developed, including: (1) servo-hydraulic system for the loading carriage; (2) amplification and read-out system for pressure cells; (3) linearizing unit for strain coils; (4) transducers for measuring vertical and resilient deflection; (5) techniques for measuring in situ strain on fabric inclusions; (6) extensive use of nuclear density meter to monitor pavement and foundation materials. The following conclusions are drawn: (1) No improvement in performance resulted from fabric inclusions. (2) No consistent reduction in in-situ stresses, resilient strains, or permanent strains was observed as a result of fabric inclusion. (3) No consistent improvement in densities resulted from fabric inclusions. (4) Some slip apparently occurred between fabric and soil on those pavements which involved large deformations. The slip occurred between fabric and crushed limestone base rather than between fabric and silty-clay subgrade. (Author)

Recycling of paving materials is gaining acceptance as a means of savings in pavement reconstruction or rehabilitation. The need to conserve natural resources and increasing costs of select virgin materials have made recycling pavements economically attractive. Pavements that currently have low serviceability indices due to surface irregularities such as cracks, bumps, spalling, potholes, etc., may be broken up to meet specified granular base course gradation requirements and reused as a base for the new surface. CRREL developed a permafrost excavating attachment for heavy bulldozers and a prototype test rig was constructed. Tests were conducted on frozen soils, gravels, and ledge. In September 1976, this rig was used to pulverize a flexible street pavement in Hanover, N.H., and highway pavement test sections at a CRREL test facility. IThe resultant processed material met Corps of Engineers base course gradation requirements. The machine can process 120 square ft of pavement structure per minute to a depth of 12 inches. The most uniformly graded material was obtained at a drum speed of 15 revolutions per minute. Once the pavement is broken down from the solid mass (asphalt concrete pavement), the machine does not further break down or pulverize the aggregate. A minor amount of dust was evident during the operations.

This part of Volume II consists of DD forms 1473 for contract reports, etc., which were cited in Volume I, AD-A045 024., See also Volume 2, Part 1, AD-A0451025.

This part of Volume II consists of DD forms 1473 for Bulletins, Instruction Reports and Miscellaneous Papers cited in Volume I, AD-A045 024., See also Volume 2, Part 2, AD-A045 026.

This bibliography contains citations to reports published from 1943 through 1976 by personnel of or under contract to the Waterways Experiment Station. The reports generally relate to paving materials, construction methods and equipment, and criteria and tests for design, construction control, performance and evaluation of conventional pavements and expedient surfacings for roads and airfields. Volume I includes Part 1, a list of reports, and Part 2, indexes by subject, personal author, corporate author, and airfield and military base. Volume II includes Part 1, Report Documentation Page data (DD Form 1473) for Bulletins, Instruction Reports, and Miscellaneous Papers; and Part 2, Report Document Page data for Technical Memoranda, Technical Reports Pavement and Soil Trafficability Information Analysis Center Reports, and Contract Reports., See also Volume 2, Part-2, AD-A045 026.

A study was conducted on the performance of junctures between rigid and flexible airfield pavements constructed using present criteria. The study consisted of field inspections of 14 rigid-flexible pavement junctures at Williams AFB, Arizona, and Columbus AFB, Mississippi, and discussions of the performance of these junctures with Base Civil Engineering Office personnel. Of the 14 junctures studied, 4 have been repaired and are now in good condition, 1 is in good to fair condition, 1 is in only poor to fair condition, and 8 are in good condition. Although the junctures have performed generally well, the asphaltic concrete pavement portions have experienced some minor problems (namely, humping, transverse cracking, and surface depressions). From the problems associated with the junctures studied, it is recommended that the present design be revised slightly. A recommended revision of the design of rigid-flexible airfield pavement junctures is described. The revision involves use of expansion joints, increased thickness of the asphaltic concrete, and special rolling procedures for the asphaltic concrete binder and surface courses.

Problems encountered in the construction of road foundations and principal causes of road failure are summarized, and countermeasures are described on the basis of studies by the Swiss Union of Road Professionals and the Geotechnical Laboratory of Lausanne University. Preliminary survey procedures and the evaluation of data on the frost-susceptibility of soils, their bearing capacity, sensitivity to water, regional hydrological conditions, and freezing depths are discussed. Design specifications are given for foundations for flexible and rigid pavements in frost-susceptible soils, and data are tabulated and graphed., Draft trans. of Strasse und Verkehr (Switzerland) v44 p311-318 Jun 58.

Contents: Soil sample suite; Soil stabilization with cement; Soil stabilization with lime; Soil stabilization with asphalt; Performance benefits of stabilized pavement layers; When to use stabilization; Residual strength requirements for stabilized layers.

The purpose of this investigation was accomplished by conducting two series of full-scale tests using instrumented aircraft and both flexible and rigid instrumented runways. One series of tests was conducted during the cold period of the year when the average temperature of the top pavement layer was in the range of 35 to 55 F, while the second series was conducted during the hot period of the year when the average temperature was in the range of approximately 84 to 116 F. An instrumentation system was installed aboard the aircraft to measure and record the three components of force of each of the main gear assemblies of the aircraft., See also Volume 1, AD-A016 450.

This report describes a study designed to determine the relationship between airport runway pavement responses to static and dynamic aircraft loads. Two series of tests were conducted, one during cold weather and the other during warm weather, at the National Aviation Facilities Experimental Center Airport, Atlantic City, N.J. Both a flexible and a rigid pavement runway were instrumented to measure and record pavement responses to aircraft loads. Aircraft were instrumented for both series to measure the aircraft wheel loads transmitted to the pavement structures during normal aircraft operations. A common time code signal recorded along with the pavement response and aircraft load data provided the means for correlating the two types of data. Data were collected for the following basic aircraft modes of operation: static loading; creep-, low-, medium-, and high-speed taxi; high-speed braking; take-off rotation; touchdown; high-speed braking with reverse thrust; and turning.

A rational design procedure for flexible pavements is presented. The analysis of pavement structures is demonstrated using an improved computer program. Test tracks from other centres of research are used to test the ability of the program to predict permanent surface deformation under traffic loading. The creep characteristics of a dense bitumen macadam are analysed and a relationship suggested that links the permanent strain behavior under static and dynamic loading., See also report dated Apr 74, AD-A008 099.

A comparison of several forms of constitutive equation with permanent memory effects is made. It is shown that there exists a natural hierarchy of types whose limitations and restrictions are discussed herein. Specific results showing the limitations of use are given. The problem of modelling permanent set is briefly discussed.

This research examines a realistic approach for bituminous mix design for asphalt stabilized base courses. It concludes that the Air Force should continue using the Marshall Test Method for bituminous mixture design, but that current requirements for percent air voids in the mixture and percent voids filled with bitumen are too restrictive. It further concludes that test temperatures should be reduced from 140F for base course mixture design.