Evaluation of Asphalt Binder and Asphalt Mixture Healing Based on Visco-Elastic Continuum Damage Theory
Evaluation of Asphalt Binder and Asphalt Mixture Healing Based on Visco-Elastic Continuum Damage Theory

Author: Amirmohammad Bahadori

Publisher:

Published: 2020

Total Pages: 137

ISBN-13:

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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.

Fatigue Performance Evaluation of WesTrack Asphalt Mixtures Using Viscoelastic Continuum Damage Approach
Fatigue Performance Evaluation of WesTrack Asphalt Mixtures Using Viscoelastic Continuum Damage Approach

Author: Y. Richard Kim

Publisher:

Published: 2002

Total Pages: 258

ISBN-13:

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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.

Fracture Properties and Fatigue Cracking Resistance of Asphalt Binders
Fracture Properties and Fatigue Cracking Resistance of Asphalt Binders

Author: Arash Motamed

Publisher:

Published: 2012

Total Pages: 72

ISBN-13:

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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.

Fracture and Viscoelastic Properties of Asphalt Binders During Fatigue and Rest Periods
Fracture and Viscoelastic Properties of Asphalt Binders During Fatigue and Rest Periods

Author: Shihui Shen

Publisher:

Published: 2014

Total Pages: 10

ISBN-13:

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Viscoelastic asphalt binder plays an important role in bonding individual aggregate particles and contributes to the durability and stability of asphalt pavement. When asphalt binder is subjected to cyclic loading, deformation and fracture may develop simultaneously within it, leading to the deterioration of material properties and eventually fatigue failure. Research has found that some degree of recovery may develop if rest periods are applied after fatigue deterioration. However, it is not clear whether such recovery is caused by fracture healing, viscoelastic recovery, or both. This paper presents an analysis to differentiate the contributions of fracture healing and viscoelastic recovery to the asphalt binder during rest periods. It also evaluates the damage caused by deformation and fracture during a fatigue process. It is found that viscoelastic recovery plays an important role in the instant increase in the dynamic shear modulus at the beginning of the rest period. The effect of fracture healing on dynamic shear modulus recovery is more dominant in the long term. A healing index is developed based only on the fracture healing of asphalt binder, excluding the effect of viscoelastic recovery. It can be used to evaluate the true healing properties of different asphalt binders.

Long and Deep Tunnels
Long and Deep Tunnels

Author: Vittorio Guglielmetti

Publisher: CRC Press

Published: 2016-04-15

Total Pages: 1336

ISBN-13: 0415558549

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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.

Bituminous Mixtures and Pavements VI
Bituminous Mixtures and Pavements VI

Author: A. Nikolaides

Publisher: CRC Press

Published: 2015-07-28

Total Pages: 884

ISBN-13: 1315668165

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Bituminous Mixtures and Pavements contains 113 accepted papers from the 6th International ConferenceBituminous Mixtures and Pavements (6th ICONFBMP, Thessaloniki, Greece, 10-12 June 2015). The 6th ICONFBMP is organized every four years by the Highway Engineering Laboratory of the Aristotle University of Thessaloniki, Greece, in conjunction with

Proceedings of the RILEM International Symposium on Bituminous Materials
Proceedings of the RILEM International Symposium on Bituminous Materials

Author: Hervé Di Benedetto

Publisher: Springer Nature

Published: 2021-09-25

Total Pages: 1806

ISBN-13: 3030464555

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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.