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Implementation And Validation Of The Viscoelastic Continuum Damage Theory For Asphalt Mixture And Pavement Analysis In Brazil
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Book Synopsis Implementation and Validation of the Viscoelastic Continuum Damage Theory for Asphalt Mixture and Pavement Analysis in Brazil by : Luis Alberto Herrmann do Nascimento
Download or read book Implementation and Validation of the Viscoelastic Continuum Damage Theory for Asphalt Mixture and Pavement Analysis in Brazil written by Luis Alberto Herrmann do Nascimento and published by . This book was released on 2015 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fatigue Performance Evaluation of WesTrack Asphalt Mixtures Using Viscoelastic Continuum Damage Approach by : Y. Richard Kim
Download or read book Fatigue Performance Evaluation of WesTrack Asphalt Mixtures Using Viscoelastic Continuum Damage Approach written by Y. Richard Kim and published by . This book was released on 2002 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction -- Objectives and summary -- Theoretical background -- Test methods -- Materials and specimen fabrication -- Uniaxial testing -- Determination of viscoelastic properties from IDT test -- Development of a simple performance test and validation -- Conclusions and recommendations -- Implementation and technology transfer plan -- References -- Appendices.
Book Synopsis Evaluation of Asphalt Binder and Asphalt Mixture Healing Based on Visco-Elastic Continuum Damage Theory by : Amirmohammad Bahadori
Download or read book Evaluation of Asphalt Binder and Asphalt Mixture Healing Based on Visco-Elastic Continuum Damage Theory written by Amirmohammad Bahadori and published by . This book was released on 2020 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue cracking of asphalt pavements is one of the main distresses that reduces the serviceability of roads. The prediction of fatigue cracking in pavements is carried out using laboratory tests and mechanistic models. However, such predictions usually underestimate observed field performance. Their inability to suitably account for the self-healing capability of asphalt pavements is one of the key sources of the variation. This study presents a novel test method and a healing index based on Visco-Elastic Continuum Damage (VECD) theory to quantify the self-healing capacity of asphalt binders and mixes. The proposed asphalt binder healing test is a modification of the conventional Linear Amplitude Sweep (LAS) test, which not only considers the effect of rest periods but also minimizes the number of specimens required for the comprehensive analysis.A healing index based on released pseudo strain energy was developed to quantify the healing of asphalt binder and mixes. The analyses of healing indices for asphalt binders show that softer binders have better healing capacity at low damage levels. On the other hand, binders with higher performance grade have better healing capacity at higher damage levels. An increase in rest period duration was found to increase the healing index of asphalt binder. But the sensitivity of the healing index to the duration of rest periods decreased with damage accumulation. Studies conducted on the surface energy and intrinsic healing parameters of asphalt binder showed that the non-polar Lifshitz0́3van der Waals component of the surface energy correlated well with the healing of asphalt binder.In addition, stress-controlled fatigue tests with rest periods were used to study the healing of asphalt mixtures. The results showed that an increase in temperature and rest period duration enhanced the healing of asphalt mixes. Finally, the rest period, temperature, material integrity level, and surface energy of the asphalt binder were used to develop a phenomenological-based healing prediction model. It was verified on the healing results of a sample mix. The results of the statistical analysis of the variables demonstrated that the temperature had the highest effect on the healing of asphalt mixes.
Book Synopsis Fatigue Evaluation of Asphalt Mixtures Using Dissipated Energy and Viscoelastic Continuum Damage Approaches by :
Download or read book Fatigue Evaluation of Asphalt Mixtures Using Dissipated Energy and Viscoelastic Continuum Damage Approaches written by and published by . This book was released on 2004 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mechanisms of Cracking and Debonding in Asphalt and Composite Pavements by : William G. Buttlar
Download or read book Mechanisms of Cracking and Debonding in Asphalt and Composite Pavements written by William G. Buttlar and published by Springer. This book was released on 2018-05-26 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Premature cracking in asphalt pavements and overlays continues to shorten pavement lifecycles and creates significant economic and environmental burden. In response, RILEM Technical Committee TC 241-MCD on Mechanisms of Cracking and Debonding in Asphalt and Composite Pavements has conducted a State-of-the-Art Review (STAR), as detailed in this comprehensive book. Cutting-edge research performed by RILEM members and their international partners is presented, along with summaries of open research questions and recommendations for future research. This book is organized according to the theme areas of TC 241-MCD - i.e., fracture in the asphalt bulk material, interface debonding behaviour, and advanced measurement systems. This STAR is expected to serve as a long term reference for researchers and practitioners, as it contributes to a deeper fundamental understanding of the mechanisms behind cracking and debonding in asphalt concrete and composite pavement systems.
Book Synopsis Viscoelastic Properties of Asphalts Based on Penetration and Softening Point by : Boris Radovskiy
Download or read book Viscoelastic Properties of Asphalts Based on Penetration and Softening Point written by Boris Radovskiy and published by Springer. This book was released on 2017-11-11 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work deals with conventional and new relationships between various viscoelastic properties of road bitumen, determined under different test modes, such as constant stress, constant deformation or cyclic load. Approximate formulas have been derived for prediction of the rheological properties of asphalt based on its standard parameters such as penetration and softening point. The work is intended for researchers and engineers in road paving industry. It may be also of interest for teachers and Civil Engineering students.
Book Synopsis 8th RILEM International Conference on Mechanisms of Cracking and Debonding in Pavements by : Armelle Chabot
Download or read book 8th RILEM International Conference on Mechanisms of Cracking and Debonding in Pavements written by Armelle Chabot and published by Springer. This book was released on 2016-05-25 with total page 735 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest advances in research to analyze mechanical damage and its detection in multilayer systems. The contents are linked to the Rilem TC241 - MCD scientific activities and the proceedings of the 8th RILEM International Conference on Mechanisms of Cracking and Debonding in Pavements (MCD2016). MCD2016 was hosted by Ifsttar and took place in Nantes, France, on June 7-9, 2016. In their lifetime, pavements undergo degradation due to different mechanisms of which cracking is among the most important ones. The damage and the fracture behavior of all its material layers as well as interfaces must be understood. In that field, the research activities aims to develop a deeper fundamental understanding of the mechanisms responsible for cracking and debonding in asphalt concrete and composite (e.g. asphalt overlays placed on PCC or thin cement concrete overlay placed on asphalt layer) pavement systems.
Book Synopsis Improving the Sustainability of Asphalt Pavements Through Developing a Predictive Model with Fundamental Material Properties by : Rashid Kamel Abu Al-Rub
Download or read book Improving the Sustainability of Asphalt Pavements Through Developing a Predictive Model with Fundamental Material Properties written by Rashid Kamel Abu Al-Rub and published by . This book was released on 2009 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study presents the numerical implementation and validation of general constitutive relationships for describing the nonlinear behavior of asphalt concrete mixes. These constitutive relationships incorporate nonlinear viscoelasticity and viscoplasticity to predict the recoverable and irrecoverable responses, respectively. The nonlinear viscoelastic deformation is modeled using Schapery's model; while the irrecoverable component is represented using Perzyna's viscoplasticity theory with an extended Drucker-Prager yield surface and plastic potential that is modified to capture the distinction between the compressive and extension behavior of asphalt mixes. The nonlinear viscoelastic and viscoplastic model is represented in a numerical formulation and implemented in a finite element (FE) code using a recursive-iterative algorithm for nonlinear viscoelasticity and the radial return algorithm for viscoplasticity. Then, the model is used to analyze the nonlinear viscoelastic and viscoplastic behavior of asphalt mixtures subjected to single creep recovery tests at different stress levels and temperatures. This experimental analysis includes the separation of the viscoelastic and viscoplastic strain components. Based on this separation, a systematic procedure is presented for the identification of the material parameters associated with the nonlinear viscoelastic and viscoplastic constitutive equations. Finally, the model is applied and verified against a set of creep-recovery tests on hot mix asphalt at different stress levels and temperatures.
Book Synopsis Viscoelastic Analysis and Fatigue Characterization of Bituminous Materials in Two Length Scales Under the Influene of Aging by : Santosh Reddy Kommidi
Download or read book Viscoelastic Analysis and Fatigue Characterization of Bituminous Materials in Two Length Scales Under the Influene of Aging written by Santosh Reddy Kommidi and published by . This book was released on 2017 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue cracking in asphalt concrete (AC) is of immense importance to pavement design and analysis because it is one of the most important forms of distress that can lead to structural failure in pavement. Once started, these types of cracks can be combined with other environmental factors leading to detrimental effects such as faster rates of pavement deterioration and shortened pavement life and functionality. Currently AASHTO TP101, also known as linear amplitude sweep (LAS) specification, is being widely used to evaluate the ability of an asphalt binder to resist fatigue. The LAS method, although mechanistic in its approach, has certain drawbacks. First, the test is performed on an aged 2-mm thick binder sample, which in reality may never exist in the AC where there is a varying non-uniform thickness of the binder across the components of the AC. Secondly, the test methodology predicts an increased fatigue resistance at lower strain levels of load when the binder ages. This is in contrast to the general belief among researchers that aging is one of the primary contributors to the acceleration of pavement cracking. This study aims to evaluate fatigue resistance in a more realistic approach that is more likely to exist in AC by incorporating sand asphalt mixtures. First, the linear viscoelastic properties of binder and sand asphalt mixture samples were evaluated to obtain the material properties under the influence of aging. Later, the fatigue tests on the sand asphalt mixture were investigated to understand the influence of a thin film of binder on the fatigue resistance. It was observed that based energy dissipation criterion for the binder evaluated a reasonable estimate for fatigue damage at relatively lower temperatures, but was limited to capture the influence of aging. Moreover, it was observed that fatigue testing on a binder at an intermediate temperature of 25 °C could cause edge effects to dominate as seen in the plateau regime for the phase angle in the time sweep tests. In order to overcome the edge effects in the binder LAS tests, the sand asphalt mixture testing was used for analyzing the binder fatigue resistance. Sand asphalt mixture testing could capture the microcracking and macrocracking phases more distinctively when compared to binder testing. In the case of pressure aging vessel (PAV) aged samples, it was observed that the macrocracking phase disappeared and was replaced by sudden changes in the material properties, indicating that the PAV aged mixture was more susceptible to fatigue cracking. By using the simplified viscoelastic continuum damage approach, the fatigue resistance of the binder and sand asphalt mixture was evaluated. The sand asphalt mixture testing was better to capture the influence of aging and changes in the microstructure during fatigue in comparison to binder fatigue tests..
Book Synopsis Prediction of Thermal Cracking in Asphalt Pavements Using Simplified Viscoelastic Continuum Damage Theory by : Behrooz Keshavarzi
Download or read book Prediction of Thermal Cracking in Asphalt Pavements Using Simplified Viscoelastic Continuum Damage Theory written by Behrooz Keshavarzi and published by . This book was released on 2019 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Viscoelastic, Fatigue Damage, and Permanent Deformation Characterization of High Rap Bituminous Mixtures Using Fine Aggregate Matrix (FAM) by : Hesamaddin Nabizadeh
Download or read book Viscoelastic, Fatigue Damage, and Permanent Deformation Characterization of High Rap Bituminous Mixtures Using Fine Aggregate Matrix (FAM) written by Hesamaddin Nabizadeh and published by . This book was released on 2015 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: Performance characteristics of bituminous mixtures play the most influential role in designing flexible pavement. These asphaltic mixtures can be considered as heterogeneous mixtures which composed of two primary components: fine aggregate matrix (FAM) phase and aggregate phase. The FAM phase acts as a critical phase in evaluating the performance characteristics including viscoelastic, fatigue damage, and permanent deformation characteristics of entire asphalt mixtures. This study evaluates the viscoelastic, fatigue damage and permanent deformation characteristics of bituminous mixtures containing 65% reclaimed asphalt pavement (RAP) by performing oscillatory torsional shear tests of cylindrical bars of FAM using a dynamic mechanical analyzer. Moreover, this study investigates a linkage between performance characteristics of asphalt concrete (AC) mixture and its corresponding FAM phase. To meet the objectives of this study, laboratory tests were performed for several FAM mixtures with 65% reclaimed asphalt pavement and different types of rejuvenators and one warm mix asphalt (WMA) additive. Test results were then analyzed using viscoelastic theories and fatigue prediction models based on continuum damage mechanics. Furthermore, obtained laboratory test results were compared with corresponding test results of asphalt concrete mixtures. The test results indicated that rejuvenators change properties and performance behavior related to fatigue damage and permanent deformation of high reclaimed asphalt pavement mixtures. In addition, test results of FAM phase were generally linked well with asphalt concrete mixture test results, and they vividly depicted that FAM phase could provide core information to predict the behavior of the asphalt concrete mixture.
Book Synopsis Development of a Multiaxial Viscoelastoplastic Continuum Damage Model for Asphalt Mixtures by :
Download or read book Development of a Multiaxial Viscoelastoplastic Continuum Damage Model for Asphalt Mixtures written by and published by . This book was released on 2009 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Microdamage Healing in Asphalt and Asphalt Concrete: A viscoelastic continuum damage fatigue model of asphalt concrete with microdamage healing (FHWA-RD-98-144) by :
Download or read book Microdamage Healing in Asphalt and Asphalt Concrete: A viscoelastic continuum damage fatigue model of asphalt concrete with microdamage healing (FHWA-RD-98-144) written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objectives of the study were to: (1) Demonstrate that microdamage healing occurs and that it can be measured in the laboratory and in the field, (2) Confirm that the same fracture properties that control propagation of visible cracks control the propagation of microcracks, (3) Identify the asphalt constituents which influence microdamage and microdamage healing, (4) Establish appropriate correlations between microdamage and microdamage healing in the laboratory and in the field, and (5) Predict the effect of microdamage healing on pavement performance and develop the appropriate constitutive damage models that account for the effects of microdamage healing on the performance of asphalt concrete pavement layers.
Book Synopsis Evaluation of Viscoelastic Poisson's Ratio and Anisotropy of Asphalt Mixtures by : Nasser Abdullah Alanazi
Download or read book Evaluation of Viscoelastic Poisson's Ratio and Anisotropy of Asphalt Mixtures written by Nasser Abdullah Alanazi and published by . This book was released on 2016 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Poisson's Ratio (PR) of asphalt mixtures is an important input parameter in the constitutive models for pavement design and performance analysis. The design and performance analysis of asphalt pavements depend upon measuring proper material properties such as complex modulus and PR. The PR is often assumed to be time independent or it is calculated as the negative ratio of transverse to axial strains in the time domain under uniaxial loading when the time dependency is considered. This study presented and used accurate methods to calculate the viscoelastic PR under various loading conditions and demonstrated the error associated with using inaccurate methods for calculating the PR. The results of this study demonstrated that the viscoelastic PR increased with time in uniaxial unconfined tension and compression tests where shear relaxation was generally faster than dilatational relaxation. While the viscoelastic PR decreased with time in uniaxial confined compression tests where the dilatational relaxation was faster than the shear relaxation. In addition, the results demonstrated that asphalt mixtures with coarse aggregate gradations had lower viscoelastic PR compared to asphalt mixtures with finer aggregate gradations. Also, the viscoelastic PR was found to be sensitive to the aging and moisture conditions. The viscoelastic PR decreased with aging and increased with the level and time of moisture conditioning of the asphalt mixtures. Finally, the error introduced by incorrectly calculating the PR as the negative ratio of transverse to axial strains in the time domain was found to be significant in some cases while it was insignificant in others. In addition, this study explored the anisotropy of asphalt mixtures. A proper understanding of the anisotropic behavior of asphalt mixtures is needed for an accurate multiaxial characterization of asphalt mixtures under different conditions. Asphalt mixtures are subjected to various loading conditions while in service. This study tested asphalt mixture specimens subjected to hydrostatic pressure to evaluate the degree of anisotropy at various conditions. The results demonstrated that the degree of anisotropy is dependent on the mix design. Asphalt mixtures with coarse aggregate gradations were found to have higher level of anisotropy compared to mixtures with finer aggregate gradations. In addition, the degree of anisotropy increased with the increase of confining pressure and temperature. Finally, the porosity of asphalt mixture had relatively significant impact on the degree of anisotropy. The anisotropy increased with the increase of porosity. The analysis of the anisotropy using the X-ray CT and image analysis techniques confirmed that the degree of anisotropy decreases with the increase of density.
Book Synopsis Development and Numerical Implementation of Nonlinear Viscoelastic-viscoplastic Model for Asphalt Materials by : Chien-Wei Huang
Download or read book Development and Numerical Implementation of Nonlinear Viscoelastic-viscoplastic Model for Asphalt Materials written by Chien-Wei Huang and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hot mix asphalt (HMA) is a composite material which consists of aggregates, air voids and asphalt materials. The HMA response is typically described to be viscoelastic-viscoplastic, and its response is a function of temperature, stress/strain rate, and stress/strain level. Many researches have shown that the viscoelastic response of asphalt mixtures can be nonlinear once the stress/strain value exceeds a certain threshold level. This study presents a nonlinear viscoelastic-viscoplastic model for describing the behavior of asphalt materials under various conditions. A new method is developed in this study for separating the viscoelastic response from the viscoplastic response. The first part of this study focuses on the implementation of Schapery nonlinear viscoelastic model in finite element (FE) using a user-defined material subroutine (UMAT) within the ABAQUS commercial software. The FE implementation employs the recursive-iterative integration algorithm, which can improve the convergence and save the calculating time. The verification of the nonlinear viscoelastic model is achieved by analyzing (1) the response of asphalt mixtures tested in the Simple Shear Test (SST) at several temperatures and stress levels, (2) the response of unaged and aged asphalt binders tested in the Dynamic Shear Rheometer (DSR), and (3) the response of asphalt binders in the multiple stress creep recovery test (MSCR). In the second part of this study, the nonlinear viscoelastic-viscoplastic constitutive relationship is implemented using UMAT. The viscoplastic component of the model employs Perzyna0́9s theory with Extended Drucker-Prager yield surface which is modified to account for the difference in material response under compression and extension stress states. The study includes parametric analysis to illustrate the effect of nonlinear viscoelastic parameters and viscoplastic parameters on the asphalt mix response. The capability of the model in describing the fatigue and permanent deformation distresses of asphalt pavements is illustrated using finite element simulations. The constitutive model developed in this study can describe the behavior of asphalt materials (asphalt binder, asphalt mastic and mixtures) under various testing conditions. This study also achieved the FE implementation of a nonlinear viscoelasticviscoplastic constitutive model that can simulate the fatigue and permanent deformation distresses of asphalt pavement structures.
Book Synopsis Fatigue Performance Evaluation of WesTrack Asphalt Mixtures Based on Viscoelastic Analysis of Indirect Tensile Test by :
Download or read book Fatigue Performance Evaluation of WesTrack Asphalt Mixtures Based on Viscoelastic Analysis of Indirect Tensile Test written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents the viscoelastic characterization of asphalt concrete in indirect tensile testing and the development of a simple performance test for fatigue cracking. The analytical solutions to calculate creep compliance and center strain from displacements measured on the specimen surface were developed based upon the theory of viscoelasticity. These developments were verified by 3-D finite element viscoelastic analysis and tests. A simple performance test was developed based on these solutions and work potential theory. To evaluate its validity, the indirect tensile tests were performed on WesTrack asphalt mixtures varying aggregate gradations, asphalt contents, and air void contents. Fracture energy obtained from indirect tensile strength testing and creep testing was highly correlated with field performance of these mixtures at WesTrack. A combination of indirect tensile creep and strength testing was proposed as a simple performance test for fatigue cracking. Recommendations for expanding the applicability of the simple performance test developed are provided.
Book Synopsis Viscoelastic{viscoplastic Damage Model for Asphalt Concrete by : Michael A. Graham
Download or read book Viscoelastic{viscoplastic Damage Model for Asphalt Concrete written by Michael A. Graham and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a continuum model for asphalt concrete incorporating non- linear viscoelasticity, viscoplasticity, mechanically-induced damage and moisture- induced damage. The Schapery single-integral viscoelastic model describes the nonlinear viscoelastic response. The viscoplastic model of Perzyna models the time- dependent permanent deformations, using a Drucker-Prager yield surface which is modified to depend on the third deviatoric stress invariant to include more complex dependence on state of stress. Mechanically-induced damage is modeled using continuum damage mechanics, using the same modified Drucker-Prager law to determine damage onset and growth. A novel moisture damage model is proposed, modeling moisture-induced damage using continuum damage mechanics; adhesive moisture- induced damage to the asphalt mastic-aggregate bond and moisture-induced cohesive damage to the asphalt mastic itself are treated separately. The analytical model is implemented numerically for three-dimensional and plane strain finite element analyses, and a series of simulations is presented to show the performance of the model and its implementation. Sensitivity studies are conducted for all model parameters and results due to various simulations corresponding to laboratory tests are presented. In addition to the continuum model, results are presented for a micromechanical model using the nonlinear-viscoelastic-viscoplastic-damage model for asphalt mastic and a linear elastic model for aggregates. Initial results are encouraging, showing the strength and stiffness of the mix as well as the failure mode varying with moisture loading. These initial results are provided as a an example of the model's robustness and suitability for modeling asphalt concrete at the mix scale.
