Physically Based Model for Predicting the Susceptibility of Asphalt Pavements to Moisture-induced Damage PDF Download
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Author: Rashid Kamel Abu Al-Rub
Publisher:
ISBN:
Category : Finite element method
Languages : en
Pages : 57
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Book Description
Author: Rashid Kamel Abu Al-Rub
Publisher:
ISBN:
Category : Finite element method
Languages : en
Pages : 57
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Book Description
Author: Maryam Shakiba
Publisher:
ISBN:
Category :
Languages : en
Pages :
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The presence and flow of moisture degrade engineering properties of asphalt concrete as part of thermodynamic, chemical, physical, and mechanical processes. This detrimental effect is referred to as moisture damage. The aim of this dissertation is the development of physically based constitutive relationships along with a computational tool for the fundamental analysis of combined mechanical and moisture induced damage of asphalt concrete. Such a tool can greatly contribute to an improved material selection procedure and give insight into the various damage inducing mechanisms in asphalt concrete. In this dissertation, thermo-hygro-mechanical constitutive relationships are developed based on the principle of virtual power and laws of thermodynamics in order to simulate moisture-induced damage of asphalt concrete. An evolution function is proposed to consider the detrimental effect of moisture diffusion and presence inside the material. The effect of pore water pressure is incorporated using Biot's coefficient. The Continuum Damage Mechanics (CDM) theory is extended to Continuum Moisture-Mechanical Damage Mechanics (CMMDM) to incorporate the moisture degradation effect and couple it to the mechanical response of asphalt concrete. The proposed moisture damage constitutive relationships are implemented in the Pavement Analysis using Nonlinear Damage Approach (PANDA) finite element (FE) package to model the moisture damage effect on the complex environmental-mechanical response of asphalt concrete. The developed constitutive relationship and framework are validated over different loading scenarios and a range of experimental measurements. The developed constitutive relationship and framework are applied to simulate pavement performance. The focus is on investigating the effects of various moisture conditioning periods on permanent deformation (rutting) and fatigue damage of asphalt pavements. The constitutive and computational models are used to develop a framework for the simulation of the effect of moisture on the microstructural response of asphalt concrete. This framework explicitly incorporates the material microstructural distribution and properties. The developed framework is used to perform two-dimensional (2D) and three-dimensional (3D) micromechanical simulations in order to study and investigate the capability of the proposed constitutive relationships to predict the microstructural response of asphalt concrete under combined effect of moisture diffusion and mechanical loading. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151963
Author: Silvia Caro Spinel
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The deleterious effect of moisture on the structural integrity of asphalt mixtures has been recognized as one of the main causes of early deterioration of asphalt pavements. This phenomenon, usually referred to as moisture damage, is defined as the progressive loss of structural integrity of the mixture that is primarily caused by the presence of moisture in liquid or vapor state. Moisture damage is associated with the development of different physical, mechanical, and chemical processes occurring within the microstructure of the mixture at different intensities and rates. Although there have been important advancements in identifying and characterizing this phenomenon, there is still a lack of understanding of the damage mechanisms occurring at the microscopic level. This situation has motivated the research work reported in this dissertation. The main objective of this dissertation is to formulate and apply a numerical micromechanical model of moisture-induced damage in asphalt mixtures. The model focuses on coupling the effects of moisture diffusion-one of the three main modes of moisture transport within asphalt mixtures-with the mechanical performance of the microstructure. Specifically, the model aims to account for the effect of moisture diffusion on the degradation of the viscoelastic bulk matrix of the mixture (i.e., cohesive degradation) and on the gradual deterioration of the adhesive bonds between the aggregates and the asphalt matrix (i.e., adhesive degradation). The micromechanical model was applied to study the role of some physical and mechanical properties of the constitutive phases of the mixtures on the susceptibility of the mixture to moisture damage. The results from this analysis suggest that the diffusion coefficients of the asphalt matrix and aggregates, as well as the bond strength of the aggregate-matrix interface, have the most influence on the moisture susceptibility of the mixtures. The micromechanical model was further used to investigate the influence of the void phase of asphalt mixtures on the generation of moisture-related deterioration processes. Two different probabilistic-based approaches were used to accomplish this objective. In the first approach, a volumetric distribution of air void sizes measured using X-Ray Computed Tomography in a dense-graded asphalt mixture was used to generate probable void structures in a microstructure of an asphalt mixture. In the second approach, a stochastic modeling technique based on random field theory was used to generate probable air void distributions of the mixture. In this second approach, the influence of the air void was accounted for by taking the physical and mechanical properties of the asphalt matrix dependent on probable void distributions. Although both approaches take into consideration the characteristics of the air void phase on the mechanical response of the mixtures subjected to moist environments, the former explicitly introduces the air phase within the microstructure while the latter indirectly includes its effects by modifying the material properties of the bulk matrix. The results from these simulations demonstrated that the amount, variability and location of air voids are decisive in determining the moisture-dependent performance of asphalt mixtures. The results from this dissertation provide new information on the kinetics of moisture damage mechanisms in asphalt mixtures. In particular, the results obtained from applying the micromechanical model permitted identification of the relative influence of the characteristics of the constitutive phases of a mixture on its moisture-related mechanical performance. This information can be used as part of design methodologies of asphalt mixtures, and/or as an input in life-cycle analysis models and maintenance programs of road infrastructure.
Author: Hervé Di Benedetto
Publisher: Springer Nature
ISBN: 3030464555
Category : Technology & Engineering
Languages : en
Pages : 1806
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Book Description
This volume highlights the latest advances, innovations, and applications in bituminous materials and structures and asphalt pavement technology, as presented by leading international researchers and engineers at the RILEM International Symposium on Bituminous Materials (ISBM), held in Lyon, France on December 14-16, 2020. The symposium represents a joint effort of three RILEM Technical Committees from Cluster F: 264-RAP “Asphalt Pavement Recycling”, 272-PIM “Phase and Interphase Behaviour of Bituminous Materials”, and 278-CHA “Crack-Healing of Asphalt Pavement Materials”. It covers a diverse range of topics concerning bituminous materials (bitumen, mastics, mixtures) and road, railway and airport pavement structures, including: recycling, phase and interphase behaviour, cracking and healing, modification and innovative materials, durability and environmental aspects, testing and modelling, multi-scale properties, surface characteristics, structure performance, modelling and design, non-destructive testing, back-analysis, and Life Cycle Assessment. The contributions, which were selected by means of a rigorous international peer-review process, present a wealth of exciting ideas that will open novel research directions and foster new multidisciplinary collaborations.
Author: Vittorio Guglielmetti
Publisher: CRC Press
ISBN: 0415558549
Category : Technology & Engineering
Languages : en
Pages : 1336
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Book Description
The design and construction of “long and deep” tunnels, i.e. tunnels under mountains, characterised by either considerable length and/or overburden, represent a considerable challenge. The scope of this book is not to instruct how to design and construct such tunnels but to share a method to identify the potential hazards related to the process of designing and constructing long and deep tunnels, to produce a relevant comprehensive analysis and listing, to quantify the probability and consequences, and to design proper mitigation measures and countermeasures. The design, developed using probabilistic methods, is verified during execution by means of the so called Plan for Advance of the Tunnel (PAT) method, which allows adapting the design and control parameters of the future stretches of the tunnel to the results of the stretches already finished, using the monitoring data base. Numerous criteria are given to identify the key parameters, necessary for the PAT procedure. Best practices of excavation management with the help of real time monitoring and control are also provided. Furthermore cost and time evaluation systems are analysed. Finally, contractual aspects related to construction by contract are investigated, for best development and application of models more appropriate for tunnelling-construction contracts. The work will be of interest to practising engineers, designers, consultants and students in mining, underground, tunnelling, transportation and construction engineering, as well as to foundation and geological engineers, urban planners/developers and architects.
Author: Bradley J. Bruce
Publisher:
ISBN:
Category :
Languages : en
Pages : 104
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Book Description
Many asphalt, aggregate, mineral filler and chemical additive combinations were tested for the correlation of the 'E' Modulus Test with visual assessment of the condition of the asphalt aggregate specimen and the results of other tests methods including Marshall Method, Resilient Modulus, Immersion Compression and Maximum Tensile Stress. Specimens used in conventional tests were treated in the manner prescribed by the method. Specimens for 'E' Modulus, Resilient Modulus and Maximum Tensile Stress were tested both before and after subjecting them to severe artificial conditions that were conceived as comparable to several years of natural exposure to the elements. 'E' Modulus was judged to be too inconsistent with other variables to be used as an acceptable criteria. The data suggests that Maximum Tensile Stress and Resilient Modulus tests would be valid tools for the evaluation of asphalt aggregate susceptibility to moisture damage. Immersion Compression data could be interpreted to provide information about stripping resistance and could serve to aid in the fabrication of mixes with reduced moisture susceptibility. The Marshall Method Testing provided inconsistent indications of moisture susceptibility using either flow or stability values.
Author:
Publisher:
ISBN:
Category : Asphalt concrete
Languages : en
Pages : 60
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Book Description
Author: Christopher J. DeCarlo
Publisher:
ISBN:
Category : Artificial intelligence
Languages : en
Pages :
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Book Description
The objectives of this study were to determine a suitable set of tests to use with a moisture-conditioning process and to develop a machine learning model to predict the moisture susceptibility of hot mix asphalt. Laboratory-compacted samples of 17 plant-produced mixes with known field performance were subjected to mechanical tests before and after moisture conditioning with the moisture-induced stress tester (MiST). Statistical analysis showed that seismic modulus and indirect tensile strength were effective in distinguishing the poor-performing mixes from the well-performing mixes. Principal component analysis was conducted on the test data, and a reduced set of dimensions that were capable of explaining much of the variance in the data was identified. The significant test properties were used to develop machine learning models with two supervised classification approaches. The k-nearest neighbor model was found to be very accurate in differentiating the mixes. The use of MiST conditioning, the specified physical tests, and machine learning methods is recommended for the identification of moisture-susceptible hot-mix asphalt.
Author: Kevin D. Stuart
Publisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages : 36
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Book Description
Procedures for evaluating the moisture susceptibility of asphalt mixtures were compared by performing them on mixtures having a known history of susceptibility. Data included the retained ratios, visual stripping, mechanical values (tensile strength, stability, etc.), saturation, and swell. The most promising procedures appeared to be the NCHRP 246 and NCHRP 274.
Author: Russell G. Hicks
Publisher: Transportation Research Board
ISBN: 9780309049245
Category : Technology & Engineering
Languages : en
Pages : 104
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Book Description
This synthesis will be of interest to pavement designers, construction engineers, maintenance engineers, and others interested in avoiding or limiting moisture damage in asphalt concrete. Information is provided on physical and chemical explanations for moisture damage in asphalt concrete, along with a discussion of current practices and test methods for determining or reducing the susceptibility of various asphalt concrete components and mixtures to such damage. Moisture damage in asphalt concrete is a nationwide problem which often necessitates premature replacement of highway pavement surfaces. This report of the Transportation Research Board describes the underlying physical and chemical phenomena responsible for such damage. Current test methods used to determine the susceptibility of asphalt concretes, or their constituents, to moisture damage are described and evaluated. Additionally, current practices for minimizing the potential for moisture damage are examined.
