Mechanical Mixture Simulation Devices for Determining and Calibrating Internal Angle of Gyration in Superpave Gyratory Compactor

2006 ◽  
Vol 1970 (1) ◽  
pp. 99-105
Author(s):  
R. Michael Anderson ◽  
Kevin D. Hall ◽  
Michael Huner
Keyword(s):  
Mechanical Mixture ◽  
Superpave Gyratory Compactor ◽  
Internal Angle

Establishment of the Precision of a Rapid-Angle Measurement Device for Superpave Gyratory Compactors

2005 ◽  
Vol 1929 (1) ◽  
pp. 97-103
Author(s):  
Kevin D. Hall ◽  
Tamara Easley
Keyword(s):  
Hot Mix Asphalt ◽  
Angle Measurement ◽  
Study Data ◽  
Interlaboratory Study ◽  
Measurement Device ◽  
Superpave Gyratory Compactor ◽  
Internal Angle ◽  
Dynamic Angle

Superpave® hot-mix asphalt (HMA) specimens are compacted in the laboratory with the Superpave gyratory compactor (SGC) through pressure and an applied angle of gyration. The original compaction specification for the SGC requires the angle of gyration to be 22 ± 0.35 mrad (1.25 ± 0.02 degrees), measured externally to the compaction mold. Questions concerning the ability of different compactors to produce HMA specimens of the same mix with the same density led to the development of the dynamic angle validation (DAV) kit, which measures the angle of gyration internally (on the inside of the mold). The DAV procedure requires the use of HMA to measure the internal angle of gyration. Because of practical limitations of performing measurements with HMA and questions concerning the “proper” HMA mix to use in the measurements, a device–-the rapid-angle measurement (RAM)–-was introduced to simulate effectively the load placed on the SGC by an HMA specimen. An interlaboratory study was conducted in accordance with ASTM E691-99 to establish the precision of the internal angle measurement provided by the RAM. A total of 11 RAM units and five SGC models were included in the study. On the basis of the study data, estimates were developed of both repeatability (within lab) and reproducibility (between lab) for the RAM device for all five SGC models. It is recommended that all devices with the reported ability to measure internal angle of gyration be subjected to a similar interlaboratory study to compare devices on an equal basis.

Structure and properties of gas-dynamic coatings and evaluation of their use in sliding friction pairs

2020 ◽  
pp. 260-266
Author(s):  
V.E. Arkhipov ◽  
T.I. Murav’eva ◽  
M.S. Pugachev ◽  
O.O. Shcherbakova
Keyword(s):  
Aluminum Oxide ◽  
Sliding Friction ◽  
Metal Layer ◽  
Structural Phase ◽  
Mechanical Mixture ◽  
Structural Factors ◽  
Coating Structure ◽  
Corundum Structure ◽  
Deposited Metal ◽  
Copper Zinc

The problems of changes in the coating structure depending on the composition of the sprayed mechanical mixture using copper particles and mixture of copper and zinc particles (" brass") and the effect of structural factors on the tribological properties of the deposited metal layer are considered. The results of X-ray structural, phase, chemical and durometric analyzes, as well as tribological testing of coatings are presented. It is found that structure with hardness of ≈102.7 HV is formed in the coating from mechanical mixture of particles of copper and aluminum oxide (corundum). Numerous pores are observed in the structure of the deposited metal layer, the main size of which does not exceed 2 μm. In the coating from mechanical mixture of particles copper, zinc and aluminum oxide (corundum), structure is formed based on copper with hardness of ≈106.5 HV, zinc — ≈49.7 HV, intermetallic compounds (γ- and ε-phases) — ≈168.7 HV, the mass fraction of which is 62.0, 7.9 and 24.2 %, respectively. Both coatings can be used in sliding friction pairs.

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