In road industry, the construction of asphalt concrete layers is a dynamic process that, if not p... more In road industry, the construction of asphalt concrete layers is a dynamic process that, if not properly done, will lead to problems compromising the pavement performance. One of the most common problems is poor compaction leading to air-void volume above the maximum acceptable. This study discusses the impact of compaction/density deficiencies and presents an innovative model to calculate the asphalt pavement service-life loss in a simple and objective way, and in line with the road construction managers needs to calculate price penalty for contractors. The model was optimized for dense graded asphalt concrete, that typically has a maximum acceptable air-void volume between 4% and 7%.
The pavement surface condition assessment is a critical component for a proper pavement managemen... more The pavement surface condition assessment is a critical component for a proper pavement management system as well as for pavement rehabilitation design. A number of devices were developed to automatically record surface distresses in a continuous survey mode, but the software required for automatic distress identification remains a big challenge. In this study, a new method named PICture Unsupervised Classification with Human Analysis (PICUCHA) is proposed to circumvent many of the limitations of existing approaches, based on a combination of human and artificial intelligence. It was designed from scratch to be capable to identify sealed and unsealed cracks, potholes, patches, different types of pavements and others. The self-learning algorithms do not use any distresses predefinition and can process images taken by cameras with different brands, technologies and resolution. This study describes some key aspects of the new method and provides examples in which PICUCHA was tested in real conditions showing accuracy up to 96.9% in image pattern detection and classification.
All pavements infer rolling resistance. Heavy trucks are influenced by the deformation, the inter... more All pavements infer rolling resistance. Heavy trucks are influenced by the deformation, the internal damping, and non-elastic behavior of the pavement materials involved. Earlier studies have been addressing the pavement type, the material type and various stages of compaction. In par with manufacturing and house construction, sustainable pavements are now becoming a requirement from authorities. There are advanced computer programs to assess the greenhouse gasemissions from construction, but less emphasis have been set on the user stage. Hence, it is important to access calculable parameters of energy losses that will occur during use. The present paper addresses some of the input parameters needed to assess rolling resistance losses for pavements in general and new flexible pavements in particular, by using neural network techniques. The results can be used for the decision-making in either bidding processes or strategic planning.
Some major roads in Sweden are being designed to carry a higher vehicle load of 74 metric tons. T... more Some major roads in Sweden are being designed to carry a higher vehicle load of 74 metric tons. This is almost 25% higher than the previous maximum legal load. There is no change of the maximum 10 ton axle load, and the 11.5 ton driving axle. Thus, in the elastic world, the change would not incur any changes in the pavement design, as the number of equivalent axle loads will remain the same, provided the freight levels are the same. However, the experience from a previous change of the legal loads showed clearly that sub base layers tended to deform at a faster rate. Hence, the specifications for sub base layer materials were changed with tougher criteria for the gradation curve. The present paper compiles experience from a failed mining truck road to address issues that may affect specifications for unbound materials.
The PICture Unsupervised Classification with Human Analysis (PICUCHA) refers to a hybrid human-ar... more The PICture Unsupervised Classification with Human Analysis (PICUCHA) refers to a hybrid human-artificial intelligence methodology for pavement distresses assessment. It combines the human flexibility to recognize patterns and features in images with the neural network ability to expand such recognition to large volumes of images. In this study, the PICUCHA performance was tested with images taken with area-scan cameras and flash light illumination over a pavement with dark textures. These images are particularly challenging for the analysis because of the lens distortion and non-homogeneous illumination, generating artificial joints that happened at random positions inside the image cells. The chosen images were previously analyzed by other software without success because of the dark coluor. The PICUCHA algorithms could analyze the images with no noticeable problem and without any image pre-processing, such as contrast or brightness adjustments. Because of the special procedure used by the pavement engineer for the key patterns description, the distresses detection accuracy of the PICUCHA for the particular image set could reach 100%.
An accurate and regular survey of the road surface distresses is a key factor for pavement rehabi... more An accurate and regular survey of the road surface distresses is a key factor for pavement rehabilitation design and management, allowing public managers to maximize the value of the continuously limited budgets for road improvements and maintenance. Manual pavement distress surveys are labor-intensive, expensive and unsafe for highly-trafficked highways. Over the years, automated surveys using various hardware devices have been developed and improved for pavement field data collection to solve the problems associated with manual surveys. However, the reliable distress detection software and the data analysis remain challenging. This study focused on the analysis of a newly-developed pavement distress classification algorithm, called the PICture Unsupervised Classification with Human Analysis (PICUCHA) method, particularly the impact of image resolutions on its classification accuracy. The results show that a non-linear relationship exists between the classification accuracy and the image resolution, suggesting that images with a resolution around 1.24 mm/pixel may provide the optimal classification accuracy when using the PICUCHA method. The findings of this study can help to improve more effective uses of the specialize software for pavement distress classification, to support decision makers to choose cameras according to their budgets and desired survey accuracy, and to evaluate how existing cameras will perform if used with PICUCHA.
All pavements contribute to the rolling resistance of vehicles. For passenger cars, the pavement ... more All pavements contribute to the rolling resistance of vehicles. For passenger cars, the pavement influence is limited to the surface properties, but heavy trucks are influenced by the deformation, the internal damping, and non-elastic behavior of the pavement materials involved. Previous studies have been addressing the pavement type, the material type and various stages of compaction. Recently, even the effects of curling slabs on rolling resistance was assessed. As sustainable pavements are now becoming a requirement from road authorities, it is important to have access to calculable parameters of energy losses during use, and not only from construction. The present paper addresses some of the input parameters needed to assess rolling resistance losses for pavements in general and rigid pavements in particular, by using neural network techniques. The results can be used for the decision-making in either bidding processes or strategic planning.
Artificial intelligence (AI) is a group of techniques that have quite a potential to be applied t... more Artificial intelligence (AI) is a group of techniques that have quite a potential to be applied to pavement engineering and management. In this study, we developed a practical, flexible and out of the box approach to apply genetic algorithms to optimizing the budget allocation and the road maintenance strategy selection for a road network. The aim is to provide an alternative to existing software and better fit the requirements of an important number of pavement managers. To meet the objectives, a new indicator, named Road Global Value Index (RGVI), was created to contemplate the pavement condition, the traffic and the economic and political importance for each and every road section. This paper describes the approach and its components by an example confirming that genetic algorithms are very effective for the intended purpose.
The “Santa Catarina Rural” is a Program co-funded by The World Bank for improvements on 1300 km o... more The “Santa Catarina Rural” is a Program co-funded by The World Bank for improvements on 1300 km of low volume rural roads on Southern Brazil. The pioneer project under the program was on the municipality of Santa Rosa de Lima, where the greenhouse gas (GHG) emissions resulting from the road improvement activities as well as the regular traffic were assessed on an experimental basis using the CarbonROAD software application. Here, we show details of the CarbonROAD software application and the construction emissions assessment procedure as well as the mitigating effect of the plants used for compensation. It was found that most of the emissions come from the road improvement work. This includes earthworks, fuel for motor graders, bulldozers and other machines, and materials and gravel extraction, industrialization and transportation, etc. Only a smaller portion comprises regular road traffic. The accumulated emission balance shows that the carbon absorption is larger than construction emissions after just 15 months. The potential for price appraisal of the generated carbon credits is explored.
On 2008 was published (Salini et al, 2008) the guidelines to use an artificial intelligence based... more On 2008 was published (Salini et al, 2008) the guidelines to use an artificial intelligence based approach to create high quality models to asphalt pavements, surpassing most of the well know problems and limitations of the current empiric and empiricmechanistic approaches. This paper describe part of this new approach called INTELLIPave, with focus in show how to totally unknown variables are considered in the model in an implicit way, regardless its nature or complexity, and how the failure criteria is used aside, and no longer inside, of the model.
In recent history Moldova was a Soviet Republic, but gained independence in 1990 with the demise ... more In recent history Moldova was a Soviet Republic, but gained independence in 1990 with the demise of the Soviet Union. Thus, the young republic inherited a road net work and its management by Soviet ways of thinking. There have been several internationally funded projects in recent years to encourage transportation and the economy of the road sector. Modern bridge and pavement management systems are naturally an efficient tool in this effort as is asset management. Within the framework of the Design and Implementation of Road Maintenance Reform, a couple of reports were prepared by a consultancy team on Asset Valuation and Pavement Management Systems. In the present paper some of the findings leading to a Moldovan Asset Valuation method as well as Pavement Management Systems are presented. An important factor for success is a wholeheartedly participation of the people to use the systems. The team focused on informing about possible methods for an evaluation and then collaborated upon a suitable method for the country. After going through the various methods for depreciation and new evaluation, a method was chosen were the asset for a given road was a function of a survey, mostly relying on the structural value. Class limits were selected after a previously made evaluation and practical aspects. Hence, the value of an object is based on the degree of degradation between new and the salvage value. The salvage value is depending on the road type. Road types in higher road categories with bound layers have a lower salvage value in relative terms; as the earth preparation works in relation to the cost of the pavement is lower.
The objective of this work is to characterize the structural and mechanical behavior of asphalt m... more The objective of this work is to characterize the structural and mechanical behavior of asphalt mixtures, when some recycled rubber is added. The basic asphalt mixture is the one commonly used in asphalt pavement and the recycled rubber comes from used tires. The research methodology used make possible to optimize the rubber addition so that the structural behavior of resulting asphalts mixture is improved when compared to the basic mixture without rubber. The study investigates the effects of the addition of crumb tire rubber in asphalt concrete mixtures. The process of incorporation of rubber is similar to the aggregate-rubber process (dry), but seeking the asphalt-rubber process (wet). The study optimizes the asphalt binder and rubber contents with the aid of the Marshall method. The mixture performance is evaluated with the indirect tensile strength, resilient modulus and fatigue tests on Marshall samples. The pavement design simulation with the experimental mixture shows advantages compared to the conventional mixture.
O presente trabalho apresenta uma pequena revisão do estado da técnica com relação às metodologia... more O presente trabalho apresenta uma pequena revisão do estado da técnica com relação às metodologias de avaliação da capacidade estrutural dos pavimentos betuminosos a partir dos dados deflectométricos e metodologias de cálculo do raio do arco circular que descreve a bacia de deflexão. Também é apresentado o “Método Salini”, elaborado por este autor, que permite o cálculo da deformação específica de tração na fibra inferior na camada betuminosa a partir da análise da geometria da bacia de deflexão.
Este trabalho apresenta um programa de pesquisa que tem por objetivo caracterizar o comportamento... more Este trabalho apresenta um programa de pesquisa que tem por objetivo caracterizar o comportamento da mistura asfáltica (empregada em pavimentação viária) quando esta recebe a adição de borracha reciclada de pneus usados. A pesquisa a ser desenvolvida visa qualificar e quantificar o desempenho da mistura asfáltica quando a borracha reciclada é adicionada, utilizando para isso os ensaios tradicionais e trabalhando com as seguintes variáveis: quantidade e granulometria da borracha, temperatura de usinagem da mistura e emprego de aditivos. O resultado final esperado é uma mistura asfáltica com características superiores àquelas observadas em misturas convencionais e com um custo bastante reduzido quando comparado ao de misturas polimerizadas (modificadas) com o uso de polímeros virgens. Além da melhoria da qualidade técnica das misturas asfálticas esta reciclagem também amenizará o impacto ambiental do descarte dos pneus.
The Salini Method was published in 1999 as a simple but scientific way to calculate the strains i... more The Salini Method was published in 1999 as a simple but scientific way to calculate the strains in the last fibre in the asphalt layer from deflections measured with Benkelman Beam, FWD/HWD or any similar equipment. These strains are critical to estimate the service-life for new and existent asphalt pavements. As the pavement works under flexion, with a compressed and a tractioned area, to improve the accuracy the "neutral line position" is now introduced as variable and the method called "Salini Method 2004". The method is available as scientific publication and freeware software.
O estudo investiga os efeitos da adição de borracha de pneus em misturas de concreto asfáltico. A... more O estudo investiga os efeitos da adição de borracha de pneus em misturas de concreto asfáltico. A reação da borracha com o ligante asfáltico foi observada através do microscópio. O processo de incorporação da borracha é similar ao processo “borracha-agregado” (seco), mas buscando-se as características do processo “asfalto-borracha” (úmido). O estudo otimizou as quantidades ótimas de asfalto e borracha com a ajuda do Método Marshall. O desempenho da mistura foi avaliado através da resistência à tração por compressão diametral, módulo de resiliência e vida de fadiga por carga repetitiva em corpos de prova Marshall.O dimensionamento simulado demonstrou as vantagens da mistura experimental (com borracha) comparativamente com a mistura convencional (sem borracha).
Este artigo é uma tradução para o português do original publicado pelos mesmos autores e intitulado "Study of Recycled Tyre Rubber in Asphalt Concrete Mixtures" (2000)
Modelling the service life for asphalt pavements is widely made with base on empirical methods, d... more Modelling the service life for asphalt pavements is widely made with base on empirical methods, developed half-century ago, with poor results. The new reality of the XXI century, with high construction costs, environmental restrictions and growing volumes of vehicles in the highways, enforce the shift to a new level of quality and accuracy to predict the service life of the pavements. This paper presents some insights either theoretical or experimental into a making from the ground, of an approach to predict and model the asphalt pavement behaviour using soft computing tools and, at the same time, create a way to accumulate the knowledge in this engineering field. The knowledge about the asphalt pavement life cycle is organized in a hierarchical way in order to be reused in a formal way, leading to an evolutionary process of adaptation and construction (Neves et al. 2007).
The study investigates the effects of the addition of crumb tyre rubber in asphalt concrete mixtu... more The study investigates the effects of the addition of crumb tyre rubber in asphalt concrete mixtures. The reaction of crumb rubber in the asphalt binder is observed through a microscope. The process of incorporation of rubber is similar to the aggregate-rubber process (dry), but seeking the asphalt-rubber process (wet). The study optimises the asphalt binder and rubber contents with the aid of the Marshall method. The mixture performance is evaluated with the indirect tensile strength, resilient modulus and fatigue tests on Marshall samples. The pavement design simulation with the experimental mixture shows advantages compared to the conventional mixture.
After the implementation of the AASHTO Road Test many researches have been carried out regarding ... more After the implementation of the AASHTO Road Test many researches have been carried out regarding material and pavement performance, both in laboratory and in situ. Many methods for pavement evaluation and design were obtained based on empirical or empirical-mechanistic approaches. Nowadays, these methods are used in pavement analysis and design supported by a set of shift factors that consider the variables which were not included in their definitions. At the present time, the development of economical electronic sensors has made possible a successful full-scale instrumentation of pavements that include a set of variables which were not considered in the past. This paper focuses on reporting the instrumentation selected for a full scale research in Portugal led by the University of Minho, and some basic and limited considerations to collect relevant data for pavement modelling. The instrumentation includes monitoring environmental conditions (rainfall, air temperature, solar and UV radiations, and wind), pavement characteristics (temperature, moisture and groundwater level), pavement response (displacement, tensile and compression strains, deformations and pressures) and vehicle characteristics (type, axle configuration, tire type and pressure, speed, weight by axle at high speed and the transversal wandering). The definition of the instrumentation for pavement response was based on conventional pavement analysis using numerical modelling in which the sensors position may ensure reliable measurements. External parameters evaluation, such as tire pressure and tire pattern, is included by sample-collection.
In road industry, the construction of asphalt concrete layers is a dynamic process that, if not p... more In road industry, the construction of asphalt concrete layers is a dynamic process that, if not properly done, will lead to problems compromising the pavement performance. One of the most common problems is poor compaction leading to air-void volume above the maximum acceptable. This study discusses the impact of compaction/density deficiencies and presents an innovative model to calculate the asphalt pavement service-life loss in a simple and objective way, and in line with the road construction managers needs to calculate price penalty for contractors. The model was optimized for dense graded asphalt concrete, that typically has a maximum acceptable air-void volume between 4% and 7%.
The pavement surface condition assessment is a critical component for a proper pavement managemen... more The pavement surface condition assessment is a critical component for a proper pavement management system as well as for pavement rehabilitation design. A number of devices were developed to automatically record surface distresses in a continuous survey mode, but the software required for automatic distress identification remains a big challenge. In this study, a new method named PICture Unsupervised Classification with Human Analysis (PICUCHA) is proposed to circumvent many of the limitations of existing approaches, based on a combination of human and artificial intelligence. It was designed from scratch to be capable to identify sealed and unsealed cracks, potholes, patches, different types of pavements and others. The self-learning algorithms do not use any distresses predefinition and can process images taken by cameras with different brands, technologies and resolution. This study describes some key aspects of the new method and provides examples in which PICUCHA was tested in real conditions showing accuracy up to 96.9% in image pattern detection and classification.
All pavements infer rolling resistance. Heavy trucks are influenced by the deformation, the inter... more All pavements infer rolling resistance. Heavy trucks are influenced by the deformation, the internal damping, and non-elastic behavior of the pavement materials involved. Earlier studies have been addressing the pavement type, the material type and various stages of compaction. In par with manufacturing and house construction, sustainable pavements are now becoming a requirement from authorities. There are advanced computer programs to assess the greenhouse gasemissions from construction, but less emphasis have been set on the user stage. Hence, it is important to access calculable parameters of energy losses that will occur during use. The present paper addresses some of the input parameters needed to assess rolling resistance losses for pavements in general and new flexible pavements in particular, by using neural network techniques. The results can be used for the decision-making in either bidding processes or strategic planning.
Some major roads in Sweden are being designed to carry a higher vehicle load of 74 metric tons. T... more Some major roads in Sweden are being designed to carry a higher vehicle load of 74 metric tons. This is almost 25% higher than the previous maximum legal load. There is no change of the maximum 10 ton axle load, and the 11.5 ton driving axle. Thus, in the elastic world, the change would not incur any changes in the pavement design, as the number of equivalent axle loads will remain the same, provided the freight levels are the same. However, the experience from a previous change of the legal loads showed clearly that sub base layers tended to deform at a faster rate. Hence, the specifications for sub base layer materials were changed with tougher criteria for the gradation curve. The present paper compiles experience from a failed mining truck road to address issues that may affect specifications for unbound materials.
The PICture Unsupervised Classification with Human Analysis (PICUCHA) refers to a hybrid human-ar... more The PICture Unsupervised Classification with Human Analysis (PICUCHA) refers to a hybrid human-artificial intelligence methodology for pavement distresses assessment. It combines the human flexibility to recognize patterns and features in images with the neural network ability to expand such recognition to large volumes of images. In this study, the PICUCHA performance was tested with images taken with area-scan cameras and flash light illumination over a pavement with dark textures. These images are particularly challenging for the analysis because of the lens distortion and non-homogeneous illumination, generating artificial joints that happened at random positions inside the image cells. The chosen images were previously analyzed by other software without success because of the dark coluor. The PICUCHA algorithms could analyze the images with no noticeable problem and without any image pre-processing, such as contrast or brightness adjustments. Because of the special procedure used by the pavement engineer for the key patterns description, the distresses detection accuracy of the PICUCHA for the particular image set could reach 100%.
An accurate and regular survey of the road surface distresses is a key factor for pavement rehabi... more An accurate and regular survey of the road surface distresses is a key factor for pavement rehabilitation design and management, allowing public managers to maximize the value of the continuously limited budgets for road improvements and maintenance. Manual pavement distress surveys are labor-intensive, expensive and unsafe for highly-trafficked highways. Over the years, automated surveys using various hardware devices have been developed and improved for pavement field data collection to solve the problems associated with manual surveys. However, the reliable distress detection software and the data analysis remain challenging. This study focused on the analysis of a newly-developed pavement distress classification algorithm, called the PICture Unsupervised Classification with Human Analysis (PICUCHA) method, particularly the impact of image resolutions on its classification accuracy. The results show that a non-linear relationship exists between the classification accuracy and the image resolution, suggesting that images with a resolution around 1.24 mm/pixel may provide the optimal classification accuracy when using the PICUCHA method. The findings of this study can help to improve more effective uses of the specialize software for pavement distress classification, to support decision makers to choose cameras according to their budgets and desired survey accuracy, and to evaluate how existing cameras will perform if used with PICUCHA.
All pavements contribute to the rolling resistance of vehicles. For passenger cars, the pavement ... more All pavements contribute to the rolling resistance of vehicles. For passenger cars, the pavement influence is limited to the surface properties, but heavy trucks are influenced by the deformation, the internal damping, and non-elastic behavior of the pavement materials involved. Previous studies have been addressing the pavement type, the material type and various stages of compaction. Recently, even the effects of curling slabs on rolling resistance was assessed. As sustainable pavements are now becoming a requirement from road authorities, it is important to have access to calculable parameters of energy losses during use, and not only from construction. The present paper addresses some of the input parameters needed to assess rolling resistance losses for pavements in general and rigid pavements in particular, by using neural network techniques. The results can be used for the decision-making in either bidding processes or strategic planning.
Artificial intelligence (AI) is a group of techniques that have quite a potential to be applied t... more Artificial intelligence (AI) is a group of techniques that have quite a potential to be applied to pavement engineering and management. In this study, we developed a practical, flexible and out of the box approach to apply genetic algorithms to optimizing the budget allocation and the road maintenance strategy selection for a road network. The aim is to provide an alternative to existing software and better fit the requirements of an important number of pavement managers. To meet the objectives, a new indicator, named Road Global Value Index (RGVI), was created to contemplate the pavement condition, the traffic and the economic and political importance for each and every road section. This paper describes the approach and its components by an example confirming that genetic algorithms are very effective for the intended purpose.
The “Santa Catarina Rural” is a Program co-funded by The World Bank for improvements on 1300 km o... more The “Santa Catarina Rural” is a Program co-funded by The World Bank for improvements on 1300 km of low volume rural roads on Southern Brazil. The pioneer project under the program was on the municipality of Santa Rosa de Lima, where the greenhouse gas (GHG) emissions resulting from the road improvement activities as well as the regular traffic were assessed on an experimental basis using the CarbonROAD software application. Here, we show details of the CarbonROAD software application and the construction emissions assessment procedure as well as the mitigating effect of the plants used for compensation. It was found that most of the emissions come from the road improvement work. This includes earthworks, fuel for motor graders, bulldozers and other machines, and materials and gravel extraction, industrialization and transportation, etc. Only a smaller portion comprises regular road traffic. The accumulated emission balance shows that the carbon absorption is larger than construction emissions after just 15 months. The potential for price appraisal of the generated carbon credits is explored.
On 2008 was published (Salini et al, 2008) the guidelines to use an artificial intelligence based... more On 2008 was published (Salini et al, 2008) the guidelines to use an artificial intelligence based approach to create high quality models to asphalt pavements, surpassing most of the well know problems and limitations of the current empiric and empiricmechanistic approaches. This paper describe part of this new approach called INTELLIPave, with focus in show how to totally unknown variables are considered in the model in an implicit way, regardless its nature or complexity, and how the failure criteria is used aside, and no longer inside, of the model.
In recent history Moldova was a Soviet Republic, but gained independence in 1990 with the demise ... more In recent history Moldova was a Soviet Republic, but gained independence in 1990 with the demise of the Soviet Union. Thus, the young republic inherited a road net work and its management by Soviet ways of thinking. There have been several internationally funded projects in recent years to encourage transportation and the economy of the road sector. Modern bridge and pavement management systems are naturally an efficient tool in this effort as is asset management. Within the framework of the Design and Implementation of Road Maintenance Reform, a couple of reports were prepared by a consultancy team on Asset Valuation and Pavement Management Systems. In the present paper some of the findings leading to a Moldovan Asset Valuation method as well as Pavement Management Systems are presented. An important factor for success is a wholeheartedly participation of the people to use the systems. The team focused on informing about possible methods for an evaluation and then collaborated upon a suitable method for the country. After going through the various methods for depreciation and new evaluation, a method was chosen were the asset for a given road was a function of a survey, mostly relying on the structural value. Class limits were selected after a previously made evaluation and practical aspects. Hence, the value of an object is based on the degree of degradation between new and the salvage value. The salvage value is depending on the road type. Road types in higher road categories with bound layers have a lower salvage value in relative terms; as the earth preparation works in relation to the cost of the pavement is lower.
The objective of this work is to characterize the structural and mechanical behavior of asphalt m... more The objective of this work is to characterize the structural and mechanical behavior of asphalt mixtures, when some recycled rubber is added. The basic asphalt mixture is the one commonly used in asphalt pavement and the recycled rubber comes from used tires. The research methodology used make possible to optimize the rubber addition so that the structural behavior of resulting asphalts mixture is improved when compared to the basic mixture without rubber. The study investigates the effects of the addition of crumb tire rubber in asphalt concrete mixtures. The process of incorporation of rubber is similar to the aggregate-rubber process (dry), but seeking the asphalt-rubber process (wet). The study optimizes the asphalt binder and rubber contents with the aid of the Marshall method. The mixture performance is evaluated with the indirect tensile strength, resilient modulus and fatigue tests on Marshall samples. The pavement design simulation with the experimental mixture shows advantages compared to the conventional mixture.
O presente trabalho apresenta uma pequena revisão do estado da técnica com relação às metodologia... more O presente trabalho apresenta uma pequena revisão do estado da técnica com relação às metodologias de avaliação da capacidade estrutural dos pavimentos betuminosos a partir dos dados deflectométricos e metodologias de cálculo do raio do arco circular que descreve a bacia de deflexão. Também é apresentado o “Método Salini”, elaborado por este autor, que permite o cálculo da deformação específica de tração na fibra inferior na camada betuminosa a partir da análise da geometria da bacia de deflexão.
Este trabalho apresenta um programa de pesquisa que tem por objetivo caracterizar o comportamento... more Este trabalho apresenta um programa de pesquisa que tem por objetivo caracterizar o comportamento da mistura asfáltica (empregada em pavimentação viária) quando esta recebe a adição de borracha reciclada de pneus usados. A pesquisa a ser desenvolvida visa qualificar e quantificar o desempenho da mistura asfáltica quando a borracha reciclada é adicionada, utilizando para isso os ensaios tradicionais e trabalhando com as seguintes variáveis: quantidade e granulometria da borracha, temperatura de usinagem da mistura e emprego de aditivos. O resultado final esperado é uma mistura asfáltica com características superiores àquelas observadas em misturas convencionais e com um custo bastante reduzido quando comparado ao de misturas polimerizadas (modificadas) com o uso de polímeros virgens. Além da melhoria da qualidade técnica das misturas asfálticas esta reciclagem também amenizará o impacto ambiental do descarte dos pneus.
The Salini Method was published in 1999 as a simple but scientific way to calculate the strains i... more The Salini Method was published in 1999 as a simple but scientific way to calculate the strains in the last fibre in the asphalt layer from deflections measured with Benkelman Beam, FWD/HWD or any similar equipment. These strains are critical to estimate the service-life for new and existent asphalt pavements. As the pavement works under flexion, with a compressed and a tractioned area, to improve the accuracy the "neutral line position" is now introduced as variable and the method called "Salini Method 2004". The method is available as scientific publication and freeware software.
O estudo investiga os efeitos da adição de borracha de pneus em misturas de concreto asfáltico. A... more O estudo investiga os efeitos da adição de borracha de pneus em misturas de concreto asfáltico. A reação da borracha com o ligante asfáltico foi observada através do microscópio. O processo de incorporação da borracha é similar ao processo “borracha-agregado” (seco), mas buscando-se as características do processo “asfalto-borracha” (úmido). O estudo otimizou as quantidades ótimas de asfalto e borracha com a ajuda do Método Marshall. O desempenho da mistura foi avaliado através da resistência à tração por compressão diametral, módulo de resiliência e vida de fadiga por carga repetitiva em corpos de prova Marshall.O dimensionamento simulado demonstrou as vantagens da mistura experimental (com borracha) comparativamente com a mistura convencional (sem borracha).
Este artigo é uma tradução para o português do original publicado pelos mesmos autores e intitulado "Study of Recycled Tyre Rubber in Asphalt Concrete Mixtures" (2000)
Modelling the service life for asphalt pavements is widely made with base on empirical methods, d... more Modelling the service life for asphalt pavements is widely made with base on empirical methods, developed half-century ago, with poor results. The new reality of the XXI century, with high construction costs, environmental restrictions and growing volumes of vehicles in the highways, enforce the shift to a new level of quality and accuracy to predict the service life of the pavements. This paper presents some insights either theoretical or experimental into a making from the ground, of an approach to predict and model the asphalt pavement behaviour using soft computing tools and, at the same time, create a way to accumulate the knowledge in this engineering field. The knowledge about the asphalt pavement life cycle is organized in a hierarchical way in order to be reused in a formal way, leading to an evolutionary process of adaptation and construction (Neves et al. 2007).
The study investigates the effects of the addition of crumb tyre rubber in asphalt concrete mixtu... more The study investigates the effects of the addition of crumb tyre rubber in asphalt concrete mixtures. The reaction of crumb rubber in the asphalt binder is observed through a microscope. The process of incorporation of rubber is similar to the aggregate-rubber process (dry), but seeking the asphalt-rubber process (wet). The study optimises the asphalt binder and rubber contents with the aid of the Marshall method. The mixture performance is evaluated with the indirect tensile strength, resilient modulus and fatigue tests on Marshall samples. The pavement design simulation with the experimental mixture shows advantages compared to the conventional mixture.
After the implementation of the AASHTO Road Test many researches have been carried out regarding ... more After the implementation of the AASHTO Road Test many researches have been carried out regarding material and pavement performance, both in laboratory and in situ. Many methods for pavement evaluation and design were obtained based on empirical or empirical-mechanistic approaches. Nowadays, these methods are used in pavement analysis and design supported by a set of shift factors that consider the variables which were not included in their definitions. At the present time, the development of economical electronic sensors has made possible a successful full-scale instrumentation of pavements that include a set of variables which were not considered in the past. This paper focuses on reporting the instrumentation selected for a full scale research in Portugal led by the University of Minho, and some basic and limited considerations to collect relevant data for pavement modelling. The instrumentation includes monitoring environmental conditions (rainfall, air temperature, solar and UV radiations, and wind), pavement characteristics (temperature, moisture and groundwater level), pavement response (displacement, tensile and compression strains, deformations and pressures) and vehicle characteristics (type, axle configuration, tire type and pressure, speed, weight by axle at high speed and the transversal wandering). The definition of the instrumentation for pavement response was based on conventional pavement analysis using numerical modelling in which the sensors position may ensure reliable measurements. External parameters evaluation, such as tire pressure and tire pattern, is included by sample-collection.
O objetivo deste trabalho foi caracterizar o comportamento estrutural e mecânico das misturas asf... more O objetivo deste trabalho foi caracterizar o comportamento estrutural e mecânico das misturas asfálticas empregadas na pavimentação rodoviária quando há a incorporação de borracha reciclada de pneus usados. A metodologia empregada resultou em significativa melhoria do desempenho estrutural da mistura asfáltica com borracha quando comparada com uma mistura de referência (sem borracha). Observou-se as alterações no desempenho das misturas variando-se as quantidades de cimento asfáltico e borracha para uma mesma composição granulométrica de agregados. As misturas foram avaliadas com base no Método Marshall e resistência à tração por compressão diametral. As misturas otimizadas também foram submetidas aos ensaios especiais (módulo de resiliência e vida de fadiga). Todos os resultados dos ensaios são apresentados.
This research is focused on the development of a new methodology called INTELLIPave, where are us... more This research is focused on the development of a new methodology called INTELLIPave, where are used artificial intelligence and numerical methods for model the asphalt pavement behavior based on data collected in the field. The INTELLIPave method is fully developed, including the procedures since the data is collected until the model application to design new pavements and evaluate existing pavements; without any simplification or concession, handling the subject in full scale. The model based on INTELLIPave method is called CUIA Model. The CUIA Model é built over specialized models with data about the climate (air temperature, rainfall, et cetera) and traffic (quantity of vehicles, classification, weights, speed, et cetera) and, if available, data about the pavement structural response (stresses, strains, et cetera) can be included. For optimum results, the data must to be collected in a highway open to real traffic until the pavement fails according a chosen criteria. Among the innovations of the INTELLIPave method are: the aside failure criteria and multiple failure criteria; the Relative Pavement Damage Index (RPDI); Scientific and rational knowledge accumulation and reuse for improve of the accuracy on future modeling; Consideration of materials aging and other pavement behaviors that change in the time (asphalt binder healing/self-recovery, et cetera); Unitarian model’s parallelization to work as a single model (CUIA Model); and, Implicit consideration of unknown variables and variables without data. INTELLIPave is the first method for asphalt pavement modeling not based on empiric or empiric-mechanistic approaches.
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Papers by Reus Salini
Este artigo é uma tradução para o português do original publicado pelos mesmos autores e intitulado "Study of Recycled Tyre Rubber in Asphalt Concrete Mixtures" (2000)
Este artigo é uma tradução para o português do original publicado pelos mesmos autores e intitulado "Study of Recycled Tyre Rubber in Asphalt Concrete Mixtures" (2000)