The Experts below are selected from a list of 13347 Experts worldwide ranked by ideXlab platform

Lubinda F Walubita - One of the best experts on this subject based on the ideXlab platform.

  • relating asphalt binder Elastic Recovery properties to hma cracking and fracture properties
    Construction and Building Materials, 2016
    Co-Authors: Jun Zhang, Lubinda F Walubita, Abu N M Faruk, Pravat Karki, Irina Holleran
    Abstract:

    Abstract Cracking in HMA pavements reduces the long-term durability of HMA pavements and undesirably increases the costs of road maintenance. Asphalt binder as one of major constituents of HMA plays an important role in the HMA cracking performance. Previous studies have indicated that higher Elastic Recovery of asphalt binder was favored to resist fatigue cracking. This study was undertaken to further investigate the relationships between the asphalt binder Elastic Recovery (ER) properties and the HMA cracking resistance and fracture properties, measured in the laboratory. The ER test (or ductility test) and MSCR test were used to measure and quantify the asphalt binder ER properties. Similarly, the OT and IDT tests were used to measure and quantify the HMA cracking resistance (cycles to crack failure) and fracture properties (tensile strength, fracture energy [FE], and FE Index), respectively. The test results indicated that HMA mixes with high ER properties (⩾59%) showed superior fracture properties and better laboratory cracking resistance performance, i.e., higher FE Index values (>1.0) and more load cycles to crack failure (>500 OT cycles), respectively. By contrast, no definitive performance trends were found for the HMA mixes with low ER properties (

  • relating asphalt binder Elastic Recovery properties to hma crack modeling and fatigue life prediction
    Construction and Building Materials, 2016
    Co-Authors: Jun Zhang, Geoffrey S Simate, Sang Ick Lee, Lubinda F Walubita
    Abstract:

    Abstract Fatigue cracking is one of the major distresses occurring in hot-mix asphalt (HMA) pavements, which is a consequence of accumulation of damage under repeated load applications and changes in the environmental conditions. HMA is predominantly composed of aggregates and asphalt binder, where the latter plays a significant role in the HMA fatigue performance. The Elastic Recovery of asphalt binders is one of the characteristic properties that are hypothesized to play a significant role in the fatigue cracking resistance of HMA pavements. In this study, the relationships between the asphalt binder Elastic Recovery properties and the HMA fatigue performance were comparatively investigated. Two asphalt binder tests, namely the Elastic Recovery (ER) and multiple stress creep Recovery (MSCR) tests were conducted to comparatively characterize the asphalt binder Elastic Recovery properties in the laboratory, and their results were then correlated to the predicted HMA fatigue life based on the TxME modeling software, which was subsequently validated with other laboratory test results and field performance data. Eleven typical Texas HMA mixes collected from different construction sites were used for the study. Overall, the results indicated that HMA mixes with high asphalt binder Elastic Recovery properties (⩾59%) exhibited better cracking resistance potential with long predicted fatigue life (>150 months), which was also consistent with other studies and field performance observations. For mixes with low Elastic Recovery properties (

R Schirrer - One of the best experts on this subject based on the ideXlab platform.

  • The ploughing friction: analytical model with Elastic Recovery for a conical tip with a blunted spherical extremity
    Tribology Letters, 2006
    Co-Authors: S Lafaye, C. Gauthier, R Schirrer
    Abstract:

    The current analytical models are insufficient to describe the ploughing part of the friction coefficient when there is Elastic Recovery at the rear part of the contact after passage of a moving tip. A solution for the case of a perfectly conical tip was proposed recently. This paper presents a model to describe the ploughing friction for a perfectly spherical tip and then develops this analysis for the case of a conical tip with a blunted spherical extremity. The major difficulty resides in taking into account the shape of the contact area in relation to the Elastic, elastoplastic or plastic behaviour of the contact.

  • Elastic Recovery of a scratch in a polymeric surface experiments and analysis
    Tribology International, 2001
    Co-Authors: Christian Gauthier, S Lafaye, R Schirrer
    Abstract:

    A scratch may be regarded as a tangential indentation. Hence standard indentation laws can be used to analyse the geometry of the scratches left by a moving tip on the surface of a viscoElastic viscoplastic body such as a commercial grade of cast polymethylmethacrylate (PMMA). This paper presents experimental results and an analysis of the Elastic Recovery of a scratch after contact with a tip. The experimental data were obtained with a new scratch apparatus fitted with a built-in microscope, which allows in situ analysis of the contact area and the groove left on the surface. The Elastic plastic total penetration depth hep is split into its plastic part hp and Elastic part he. In the case of full plasticity around the tip during scratching, which for an Elastic plastic material implies a sufficiently high value of the contact strain, the Elastic law describes the depth relaxation and experimental data agree with the analysis. In the case of a purely Elastic response of the material, corresponding to low values of the contact strain, the rear contact radius is equal to the front contact radius. At intermediate levels of strain, an analysis of the Elastic Recovery must take into account the contribution of the plastic term to the Elastic plastic response of the material.  2001 Elsevier Science Ltd. All rights reserved.

Jun Zhang - One of the best experts on this subject based on the ideXlab platform.

  • relating asphalt binder Elastic Recovery properties to hma cracking and fracture properties
    Construction and Building Materials, 2016
    Co-Authors: Jun Zhang, Lubinda F Walubita, Abu N M Faruk, Pravat Karki, Irina Holleran
    Abstract:

    Abstract Cracking in HMA pavements reduces the long-term durability of HMA pavements and undesirably increases the costs of road maintenance. Asphalt binder as one of major constituents of HMA plays an important role in the HMA cracking performance. Previous studies have indicated that higher Elastic Recovery of asphalt binder was favored to resist fatigue cracking. This study was undertaken to further investigate the relationships between the asphalt binder Elastic Recovery (ER) properties and the HMA cracking resistance and fracture properties, measured in the laboratory. The ER test (or ductility test) and MSCR test were used to measure and quantify the asphalt binder ER properties. Similarly, the OT and IDT tests were used to measure and quantify the HMA cracking resistance (cycles to crack failure) and fracture properties (tensile strength, fracture energy [FE], and FE Index), respectively. The test results indicated that HMA mixes with high ER properties (⩾59%) showed superior fracture properties and better laboratory cracking resistance performance, i.e., higher FE Index values (>1.0) and more load cycles to crack failure (>500 OT cycles), respectively. By contrast, no definitive performance trends were found for the HMA mixes with low ER properties (

  • relating asphalt binder Elastic Recovery properties to hma crack modeling and fatigue life prediction
    Construction and Building Materials, 2016
    Co-Authors: Jun Zhang, Geoffrey S Simate, Sang Ick Lee, Lubinda F Walubita
    Abstract:

    Abstract Fatigue cracking is one of the major distresses occurring in hot-mix asphalt (HMA) pavements, which is a consequence of accumulation of damage under repeated load applications and changes in the environmental conditions. HMA is predominantly composed of aggregates and asphalt binder, where the latter plays a significant role in the HMA fatigue performance. The Elastic Recovery of asphalt binders is one of the characteristic properties that are hypothesized to play a significant role in the fatigue cracking resistance of HMA pavements. In this study, the relationships between the asphalt binder Elastic Recovery properties and the HMA fatigue performance were comparatively investigated. Two asphalt binder tests, namely the Elastic Recovery (ER) and multiple stress creep Recovery (MSCR) tests were conducted to comparatively characterize the asphalt binder Elastic Recovery properties in the laboratory, and their results were then correlated to the predicted HMA fatigue life based on the TxME modeling software, which was subsequently validated with other laboratory test results and field performance data. Eleven typical Texas HMA mixes collected from different construction sites were used for the study. Overall, the results indicated that HMA mixes with high asphalt binder Elastic Recovery properties (⩾59%) exhibited better cracking resistance potential with long predicted fatigue life (>150 months), which was also consistent with other studies and field performance observations. For mixes with low Elastic Recovery properties (

Richard L Weaver - One of the best experts on this subject based on the ideXlab platform.

  • slow dynamic Elastic Recovery in unconsolidated metal structures
    Physical Review E, 2020
    Co-Authors: John Y Yoritomo, Richard L Weaver
    Abstract:

    Slow dynamic nonlinearity is widely observed in brittle materials with complex heterogeneous or cracked microstructures. It is seen in rocks, concrete, and cracked glass blocks. Unconsolidated structures show the behavior as well: aggregates of glass beads under pressure and a single glass bead confined between two glass plates. A defining feature is the loss of stiffness after a mechanical conditioning, followed by a logarithmic-in-time Recovery. Materials observed to exhibit slow dynamics are sufficiently different in microstructure, chemical composition, and scale (ranging from the laboratory to the seismological) to suggest some kind of universality. There lacks a full theoretical understanding of the universality in general and the log(time) Recovery in particular. One suspicion has been that the phenomenon is associated with glassy grain boundaries and microcracking. Seminal studies were focused on sandstones and other natural rocks, but in recent years other experimental venues have been introduced with which to inform theory. Here, we present measurements on some simple metallic systems: an unconsolidated aggregate of aluminum beads under a confining pressure, an aluminum bead confined between two aluminum plates, and a steel bead confined between steel plates. Ultrasonic waves are used as probes of the systems, and changes are assessed with coda wave interferometry. Three different methods of low-frequency conditioning are applied; all reveal slow dynamic nonlinearities. Results imply that glassy microstructures and cracking do not play essential roles, as they would appear to be absent in our systems.

S Lafaye - One of the best experts on this subject based on the ideXlab platform.

  • The ploughing friction: analytical model with Elastic Recovery for a conical tip with a blunted spherical extremity
    Tribology Letters, 2006
    Co-Authors: S Lafaye, C. Gauthier, R Schirrer
    Abstract:

    The current analytical models are insufficient to describe the ploughing part of the friction coefficient when there is Elastic Recovery at the rear part of the contact after passage of a moving tip. A solution for the case of a perfectly conical tip was proposed recently. This paper presents a model to describe the ploughing friction for a perfectly spherical tip and then develops this analysis for the case of a conical tip with a blunted spherical extremity. The major difficulty resides in taking into account the shape of the contact area in relation to the Elastic, elastoplastic or plastic behaviour of the contact.

  • Elastic Recovery of a scratch in a polymeric surface experiments and analysis
    Tribology International, 2001
    Co-Authors: Christian Gauthier, S Lafaye, R Schirrer
    Abstract:

    A scratch may be regarded as a tangential indentation. Hence standard indentation laws can be used to analyse the geometry of the scratches left by a moving tip on the surface of a viscoElastic viscoplastic body such as a commercial grade of cast polymethylmethacrylate (PMMA). This paper presents experimental results and an analysis of the Elastic Recovery of a scratch after contact with a tip. The experimental data were obtained with a new scratch apparatus fitted with a built-in microscope, which allows in situ analysis of the contact area and the groove left on the surface. The Elastic plastic total penetration depth hep is split into its plastic part hp and Elastic part he. In the case of full plasticity around the tip during scratching, which for an Elastic plastic material implies a sufficiently high value of the contact strain, the Elastic law describes the depth relaxation and experimental data agree with the analysis. In the case of a purely Elastic response of the material, corresponding to low values of the contact strain, the rear contact radius is equal to the front contact radius. At intermediate levels of strain, an analysis of the Elastic Recovery must take into account the contribution of the plastic term to the Elastic plastic response of the material.  2001 Elsevier Science Ltd. All rights reserved.