The Experts below are selected from a list of 795 Experts worldwide ranked by ideXlab platform
Kuno Kaufmann - One of the best experts on this subject based on the ideXlab platform.
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1 Compaction Monitoring Using Intelligent Soil Compactors
2015Co-Authors: Roland Dr. Anderegg, Dominik A. Von Felten, Kuno KaufmannAbstract:The nonlinear vibrations of dynamic soil Compactors are taken as the basis for feedback control systems for intelligent compaction. According to the achieved compaction, the parameters of the soil compactor are continuously changed. The vibratory roller measures permanently the stiffness of the subgrade. In conjunction with GPS-data, this measurement can be used as a QA/QC tool. The stiffness data are directly correlated to plate bearing test. In practice, the intelligent compaction ensures that the compaction job is completed in a minimum number of passes, the result is monitored and the compaction energy is automatically adjusted while measuring the soil stiffness
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Compaction Monitoring Using Intelligent Soil Compactors
GeoCongress 2006, 2006Co-Authors: Roland Dr. Anderegg, Dominik A. Von Felten, Kuno KaufmannAbstract:The nonlinear vibrations of dynamic soil Compactors are taken as the basis for feedback control systems for intelligent compaction. According to the achieved compaction, the parameters of the soil compactor are continuously changed. The vibratory roller measures the stiffness of the subgrade. In conjunction with GPS-data, this measurement can be used as a QA/QC tool. The stiffness data are directly correlated to plate bearing test. In practice, the intelligent compaction ensures that the compaction job is completed in a minimum number of passes, the result is monitored and the compaction energy is automatically adjusted while measuring the soil stiffness.
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Intelligent Compaction with Vibratory Rollers: Feedback Control Systems in Automatic Compaction and Compaction Control
Transportation Research Record, 2004Co-Authors: Roland Anderegg, Kuno KaufmannAbstract:Dynamic Compactors with parameters that adjust automatically to the condition of the subgrade form the basis for intelligent compaction. Dynamic soil Compactors create nonlinear vibrations, and the typical characteristics of these vibrations are taken as the basis for the feedback control system for intelligent compaction. With the model of the machine and the soil as the starting point, the periodic loss of contact between the drum and the subgrade is postulated to be the main nonlinear effect. This nonlinearity leads to near periodic and subharmonic vibration phenomena, and it can bring about unstable drum dynamics. The machine behavior can be investigated with the help of the chaos theory. Feedback control systems for rollers are based on the results from the theory of nonlinear oscillations, and they allow optimal compaction performance thanks to continuous adjustment to the compaction status. Starting with large amplitudes and low frequencies, the automatic control system ensures a good depth effect....
Henrique Borges Miranda - One of the best experts on this subject based on the ideXlab platform.
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influence of laboratory aggregate compaction method on the particle packing of stone mastic asphalt
Construction and Building Materials, 2020Co-Authors: Henrique Borges Miranda, Fatima Alexandra Batista, M L Antunes, Jose NevesAbstract:Abstract The type of aggregates and their packing characteristics under compaction are key factors for the design of asphalt mixtures with improved performance, namely, with respect to resistance to permanent deformation. A good example is Stone Mastic Asphalt (SMA), known by its stone–on–stone structure. In the U.S.A., the aggregate particles packing characteristics in a SMA, specially the stone–on–stone effect, are normally assessed using the “manually dry–rodded” method. However, this method may not be representative of field aggregate particle packing conditions, which may compromise the SMA performance. This article presents new findings regarding aggregate laboratory compaction methods to optimise the coarse aggregate structure in a SMA. Particle breakage, bulk density, air voids (compacted & uncompacted skeleton) in the aggregate / coarse aggregate were assessed for existing methods as well as for new methods using existing Compactors, but with different procedures and/or specific devices, e.g. Proctor hammer. The assessed methods were: (1) “non–compaction”; (2) “manually dry–rodded” method; (3) established Proctor compaction; (4) modified Proctor compaction (light and heavy compaction) and (5) steel roller compaction. The 2 latter “new methods” aimed at mechanically simulating the dry-rodded method and the effect of field Compactors, respectively. The results highlight that the new laboratory compaction methods developed with Proctor and steel roller compactor, provide a particle packing that is more representative of the field conditions, comparatively to other aggregate compaction methods.
Jose Neves - One of the best experts on this subject based on the ideXlab platform.
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influence of laboratory aggregate compaction method on the particle packing of stone mastic asphalt
Construction and Building Materials, 2020Co-Authors: Henrique Borges Miranda, Fatima Alexandra Batista, M L Antunes, Jose NevesAbstract:Abstract The type of aggregates and their packing characteristics under compaction are key factors for the design of asphalt mixtures with improved performance, namely, with respect to resistance to permanent deformation. A good example is Stone Mastic Asphalt (SMA), known by its stone–on–stone structure. In the U.S.A., the aggregate particles packing characteristics in a SMA, specially the stone–on–stone effect, are normally assessed using the “manually dry–rodded” method. However, this method may not be representative of field aggregate particle packing conditions, which may compromise the SMA performance. This article presents new findings regarding aggregate laboratory compaction methods to optimise the coarse aggregate structure in a SMA. Particle breakage, bulk density, air voids (compacted & uncompacted skeleton) in the aggregate / coarse aggregate were assessed for existing methods as well as for new methods using existing Compactors, but with different procedures and/or specific devices, e.g. Proctor hammer. The assessed methods were: (1) “non–compaction”; (2) “manually dry–rodded” method; (3) established Proctor compaction; (4) modified Proctor compaction (light and heavy compaction) and (5) steel roller compaction. The 2 latter “new methods” aimed at mechanically simulating the dry-rodded method and the effect of field Compactors, respectively. The results highlight that the new laboratory compaction methods developed with Proctor and steel roller compactor, provide a particle packing that is more representative of the field conditions, comparatively to other aggregate compaction methods.
Thomas Harman - One of the best experts on this subject based on the ideXlab platform.
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Asphalt Pavements Group
2011Co-Authors: Ghazi Ai-khateeb, Chuck Paugh, Kevin Stuart, Thomas HarmanAbstract:The Superpave gyratory compactor (SGC) is used to compact asphalt specimens for mixture testing in the Superpave system. Five companies currently manufacture SGCs for use in the United States, offering a total of eight different models. Each model employs a unique method of setting, inducing, and maintaining the specified angle of gyration. Calibration systems are required for each device for the angle of gyration. All angle measurements are made externally relative to the mold and none of the calibration systems can be universally used on all of the models. The specified external angle of gyration under load (α) is 1.25 degrees, with a tolerance of ± 0.02 degrees. The Federal Highway Administration (FHWA), in partnership with the TestQuip Corporation (New Brighton, MN), developed an angle validation kit (AVK) that measures the dynamic internal angle (DIA) of gyration. The DIA accounts for equipment compliance issues, which are not apparent in measuring the external angle. Bending in the upper and lower mold platens during compact reduces the compactive effort imparted to a specimen. Differences in specimen bulk specific gravities produced by different Compactors have bee
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Target and Tolerance Study for Angle of Gyration Used in Superpave Gyratory Compactor
Transportation Research Record, 2002Co-Authors: Ghazi Ai-khateeb, Chuck Paugh, Kevin D Stuart, Thomas Harman, John D'angeloAbstract:Five companies offer eight models of the Superpave® gyratory compactor (SGC) in the United States. Each model uses a unique method of setting and inducing the specified angle of gyration. However, all angles are set externally relative to the mold and none of the manufacturer's calibration systems can be universally applied to all models. The specified external angle of gyration (α) is 1.25° FHWA, in partnership with Test Quip, Inc., developed a dynamic angle validation kit that measures the dynamic internal angle (DIA) of gyration during loading. The DIA accounts for equipment compliance issues, such as bending of the platens during compaction, which is not apparent when the angle is measured externally. Differences in specimen density produced by different Compactors have been attributed to differences in compliance. Thus, the SGC test method needs to be revised to obtain uniformity. However, it would be inappropriate to assign the external angle of 1.25° to the DIA because the internal angle is always ...
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evaluation of superpave gyratory compactor in the field management of asphalt mixes four simulation studies
Transportation Research Record, 1995Co-Authors: Thomas Harman, John Dangelo, John R BukowskiAbstract:The SHRP-SUPERPAVE Design System utilizes the SUPERPAVE Gyratory Compactor (SGC) for asphalt-mixture specimen compaction. As part of the Demonstration Project Program, the Federal Highway Administration Office of Technology Applications (FHWA-OTA) has incorporated the SGC into FHWA-OTA mobile asphalt laboratories. Simulation studies are conducted for states to demonstrate aspects of the SUPERPAVE Design System, along with the application of certain innovative concepts in field management of asphalt mixes. The use of the SGC for field management is investigated. Four production mixes are evaluated. Based on production results, tolerance limits are established for SGC acceptance parameters. FHWA-OTA-recommended SGC volumetric acceptance parameters are asphalt binder content, voids in total mix, and voids in mineral aggregate. During the studies, companion samples were taken using the standard Marshall compactor. Results indicate that the Marshall compactor cannot be used as a surrogate for the SGC. The two compaction methods do not produce equivalent specimens.
Arkady Pikovsky - One of the best experts on this subject based on the ideXlab platform.
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spreading of energy in the ding dong model
Chaos, 2012Co-Authors: S Roy, Arkady PikovskyAbstract:We study the properties of energy spreading in a lattice of elastically colliding harmonic oscillators (Ding-Dong model). We demonstrate that in the regular lattice the spreading from a localized initial state is mediated by compactons and chaotic breathers. In a disordered lattice, the compactons do not exist, and the spreading eventually stops, resulting in a finite configuration with a few chaotic spots.
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spreading of energy in the ding dong model
arXiv: Chaotic Dynamics, 2011Co-Authors: S Roy, Arkady PikovskyAbstract:We study properties of energy spreading in a lattice of elastically colliding harmonic oscillators (Ding-Dong model). We demonstrate that in the regular lattice the spreading from a localized initial state is mediated by compactons and chaotic breathers. In a disordered lattice the compactons do not exist, and the spreading eventually stops, resulting in a finite configuration with a few chaotic spots.