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Fatigue Performance Evaluation Of Westrack Asphalt Mixtures Using Viscoelastic Continuum Damage Approach
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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 Fatigue Performance Evaluation of WesTrack Asphalt Mixtures Based on Viscoelastic Analysis of Indirect Tensile Test by : Hafiang Wen
Download or read book Fatigue Performance Evaluation of WesTrack Asphalt Mixtures Based on Viscoelastic Analysis of Indirect Tensile Test written by Hafiang Wen and published by . This book was released on 2001 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: Indirect tensile test, Simple performance test, Asphalt concrete, WesTrack, Viscoelastic.
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 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 Fatigue Performance Prediction of North Carolina Mixtures Using Simplified Viscoelastic Continuum Damage Model by : Tian Hou
Download or read book Fatigue Performance Prediction of North Carolina Mixtures Using Simplified Viscoelastic Continuum Damage Model written by Tian Hou and published by . This book was released on 2009 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: viscoelastic continuum damage, simplified model, fatigue, asphalt.
Book Synopsis Fatigue Performance Prediction of North Carolina Mixtures Using Simplified Viscoelastic Continuum Damage Model by :
Download or read book Fatigue Performance Prediction of North Carolina Mixtures Using Simplified Viscoelastic Continuum Damage Model written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue performance modeling is one the major topics in asphalt concrete modeling work. Currently the only standard fatigue test available for asphalt concrete mixtures is the flexural bending fatigue test, AASHTO T-321. There are several issues associated with flexural fatigue testing, the most important of which are the stress state is not uniform but varies over the depth of the specimen and equipment for fabricating beam specimens is not widely available. Viscoelastic continuum damage (VECD) fatigue testing is a promising alternative to flexural fatigue testing. Different researchers have successfully applied the VECD model to asphalt concrete mixtures using constant crosshead rate direct tension test. However, due to the load level limitation of the new coming Asphalt Mixture Performance Tester (AMPT) testing equipment, there is an immediate need to develop a model that can characterize fatigue performance quickly using cyclic test data. In this study, a simplified viscoelastic continuum damage model developed at NCSU is applied to various North Carolina mixtures, which are used in the NCDOT HWY-2007-7 MEPDG local calibration project. It is shown that the simplified VECD model can predict fatigue tests fairly accurately under various temperature conditions and strain levels. It is also shown that the model can be further utilized to simulate both the strain controlled direct tension fatigue test and the traditional beam fatigue test. In this thesis, simulation results are presented. Conclusions regarding the applicability of the new model are advanced as well as suggestions for further work.
Book Synopsis Development of a Simplified Fatigue Test and Analysis Procedure Using a Viscoelastic, Continuum Damage Model and Its Implementation to WesTrack Mixtures by : Jo Sias Daniel
Download or read book Development of a Simplified Fatigue Test and Analysis Procedure Using a Viscoelastic, Continuum Damage Model and Its Implementation to WesTrack Mixtures written by Jo Sias Daniel and published by . This book was released on 2001 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evaluating Mode of Loading Effect and Laboratory Fatigue Performance of Asphalt Concrete Using Viscoelastic Continuum Damage Mechanics by : Aravind Krishna Swamy
Download or read book Evaluating Mode of Loading Effect and Laboratory Fatigue Performance of Asphalt Concrete Using Viscoelastic Continuum Damage Mechanics written by Aravind Krishna Swamy and published by . This book was released on 2011 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Microdamage Healing in Asphalt and Asphalt Concrete by : Robert L. Lytton
Download or read book Microdamage Healing in Asphalt and Asphalt Concrete written by Robert L. Lytton and published by . This book was released on 2001 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Fatigue Life Characterization of Superpave Mixtures at the Virginia Smart Road by : Imad L. Al-Qadi
Download or read book Fatigue Life Characterization of Superpave Mixtures at the Virginia Smart Road written by Imad L. Al-Qadi and published by . This book was released on 2005 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laboratory fatigue testing was performed on six Superpave HMA mixtures in use at the Virginia Smart Road. Evaluation of the applied strain and resulting fatigue life was performed to fit regressions to predict the fatigue performance of each mixture. Differences in fatigue performance due to field and laboratory production and compaction methods were investigated. Also, in-situ mixtures were compared to mixtures produced accurately from the job mix formula to determine if changes occurring between the laboratory and batch plant significantly affected fatigue life. Results from the fatigue evaluation allowed verification of several hypotheses related to mixture production and compaction and fatigue performance. It was determined that location within the pavement surface, such as inner or outer wheelpath or center-of-lane, did not significantly affect laboratory fatigue test results, although the location will have significant effects on in-situ fatigue life. Also the orientation of samples cut from an in-situ pavement (parallel or perpendicular to the direction of traffic) had only a minor effect on the laboratory fatigue life, because the variability inherent in the pavement due to material variability is greater than the variability induced by compaction. Fatigue life of laboratory-compacted samples was found to be greater than fatigue life of field-compacted samples; additionally, the variability of the laboratory compacted mixture was found to be less than that of the field-compacted samples. However, it was also found that batch-plant production significantly reduces specimen variability as compared to small-batch laboratory production when the same laboratory compaction is used on both specimen sets. Finally, for Smart Road mixtures produced according to the job mix formula, the use of polymer-modified binder or stone matrix asphalt was shown to increase the expected fatigue life. However, results for all mixes indicated that fatigue resistance rankings might change depending on the applied strain level. This study contributes to the understanding of the factors involved in fatigue performance of asphalt mixtures. Considering that approximately 95% of Virginia's interstate and primary roadways incorporate asphalt surface mixtures, and that fatigue is a leading cause of deterioration, gains in the understanding of fatigue processes and prevention have great potential payoff by improving both the mixture and pavement design practices.
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 Development of a New Fatigue Performance Test Using the Hamburg Wheel Tracking Device by : Ali Sahraei Joubani
Download or read book Development of a New Fatigue Performance Test Using the Hamburg Wheel Tracking Device written by Ali Sahraei Joubani and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of this study was to develop a new test that would be simple to conduct and analyze for evaluating resistance of asphalt mixtures to fatigue cracking. For this purpose, a piece of equipment known as the Hamburg Wheel Tracking Test (HWTT) was used. HWTT has been widely accepted as a reasonable and reliable test to evaluate the rutting and moisture damage performance of asphalt mixtures but its use for evaluating fatigue resistance of asphalt mixtures is relatively a new concept. Its use as a fatigue test is advantages over current laboratory fatigue tests because of the possibility of considering various underlying support layers when the specimen is subjected to repeated loading. Ability to assess the asphalt mixture fatigue resistance in a layered system under repeated loading and in a laboratory environment provides the opportunity to integrate material design and pavement structural design for optimum performance. In addition, this test is practically feasible as a routine test method in terms of reliability, equipment availability, and data processing efficiency. The tests were conducted on a two-layer structure with the asphalt concrete slab as the top layer and the neoprene or an unbound aggregate base as the underlying layer. Based on the numerical analysis, a width of 6 inches was selected as the optimum width for this study. However, the experiment also included the 4-inch width for comparison. The thickness of the slab was selected at three levels: 1.0, 1.5, and 2.0 inches, with the 1.5-inch thickness being the main thickness applied to most of the slabs. In an asphalt pavement structure, the surface layer is often designed at a thickness of 1.5 to 2.0 inches. These tests were based on strain amplitude growth corresponding to three defined stages during the test (Early, Middle, Late). The impact of several factors on the test results was investigated. Those factors included the slab width and thickness, the underlying support type and condition, temperature of the test, the speed of tracking, and the type of asphalt mixture. The experiment showed that as the slab thickness become smaller, the strain amplitude and its corresponding growth rate become larger, exhibiting a relatively higher rate of fatigue damage. Using the unbound aggregate base proved to be challenging because of difficulty in achieving a smooth, even surface. A smooth surface was required to ensure proper bond of the gauges and collection of the data. Using synthetic rubber neoprene provided a smooth base and delivered a more reliable dataset compared to the aggregate base in this study. As expected, temperature played a significant role in the experiment, as a higher initial strain amplitude was observed at elevated temperatures. A higher strain and increased strain growth rate were observed at lower loading speeds. After determining the appropriate dimensions, temperature, and underlying support, tests were conducted on six different asphalt mixes. Strain development was monitored at the bottom of the slab for each mix. From the data collected, a new fatigue life model was developed to evaluate the fatigue performance of asphalt pavements when tested under the conditions explored in this research. The fatigue life in this model is defined as the number of HWTT load cycles at which the strain amplitude doubles, or equivalently, when the stiffness is reduced to half. This determination is made under the premise that the test operates in stress control mode. It was found that the rate of growth in strain amplitude during the test increased considerably when the binder content in the mix was decreased, validating the importance of ensuring adequate binder content in the asphalt mix. The SMA mixture demonstrated a higher rate of strain amplitude increase compared to the dense-graded mixtures. The mix with 35% RAP content and a PG 64-22 binder delivered lower growth in strain amplitude compared with other mixes. The IDEAL-CT test was also performed to draw comparisons. However, based on the outcomes, it showed no correlation with the results of the newly developed fatigue test. Based on the growth of strain amplitude throughout the test, a fatigue life model was developed. The fatigue life can be determined using this model, based on the number of cycles, with a criterion of either a 50% reduction in stiffness or a doubling of the strain amplitude. Finally, a numerical model was developed, and the observed strain response demonstrated that this model is capable of predicting both the type of response and the magnitude of strain amplitude with relative accuracy.
Book Synopsis Development of a Fast and Cost-effective Asphalt Mixture Fatigue Test System by : Aksel Seitllari
Download or read book Development of a Fast and Cost-effective Asphalt Mixture Fatigue Test System written by Aksel Seitllari and published by . This book was released on 2020 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue cracking is one of the critical distress modes in asphalt pavements. Accurate prediction and evaluation of fatigue performance are crucial to extending the service life of asphalt mixtures. Naturally, laboratory testing methods for fatigue characterization are time-consuming and require sophisticated procedures. Any effort to improve the speed and quality of the information gained from laboratory fatigue tests is valuable. This research work presents the results of a study investigating the possibility of implementing a new approach to characterize asphalt mixture fatigue behavior. This new approach includes cyclic tests run on cylindrical asphalt specimens in three-point beam mode (herein referred to as three-point bending cylinder (3PBC) geometry). Timoshenko beam theory along with the viscoelastic continuum damage (VECD) theory was implemented to model the mechanical response of the specimens. An excellent correlation between the results of 3PBC tests and uniaxial push-pull fatigue tests were observed. The 3PBC setup possesses the most advantages of uniaxial push-pull tests and includes more advantages such as not requiring a saw to cut the ends of the sample, not requiring gluing operation (and the gluing jig) and the possibility of estimating Poisson's ratio from the data. The proposed 3PBC approach was evaluated through laboratory tests conducted on various asphalt mixtures with varying binder types, mix components, and volumetric properties. The approach proposed herein was validated through finite element analysis. In addition, ruggedness evaluation of the 3PBC testing approach through varying factors and their levels were investigated and presented.
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 Fracture Properties and Fatigue Cracking Resistance of Asphalt Binders by : Arash Motamed
Download or read book Fracture Properties and Fatigue Cracking Resistance of Asphalt Binders written by Arash Motamed and published by . This book was released on 2012 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several different types of modifiers are increasingly being used to improve the performance of asphalt binders or to achieve desired mixture production characteristics (e.g., Warm Mix Asphalt). However, current Superpave performance specifications do not accurately reflect the performance characteristics of these modified binders. The main objective of this study was to evaluate the inherent fatigue cracking resistance of asphalt binders in the form of a matrix with rigid particle inclusions. The underlying rationale for this approach was to subject the binders to a state of stress that is similar to the one in a full asphalt mixture. This was achieved by fabricating and testing composite specimens of the asphalt binders and glass beads with a specified gradation. Four asphalt binders with similar true temperature grades but different modifiers were used in this study. The viscoelastic and fatigue cracking characteristics of the binders were measured using the glass bead-binder composite specimens in a dynamic shear rheometer at an intermediate temperature. The results demonstrate that the four asphalt binders modified using different methods had different damage characteristics despite the fact that these four binders were rated to have a similar performance grade based on the Superpave specifications. Fatigue cracking characteristics of the glass bead-binder test specimens used in this study were qualitatively very similar to the fatigue cracking characteristics of full asphalt mixtures using the same binders. The rank order of fatigue cracking resistance for the four glass bead-binder mixtures compared reasonably well to the rank order of fatigue cracking resistance for the full asphalt mixtures that incorporated these asphalt binders.
