What does a gyratory compactor measure?
Using gyratory compactor to measure mechanical stability of asphalt mixtures.
What is GMM in asphalt?
The theoretical maximum specific gravity (Gmm) of a HMA mixture is the specific gravity excluding air voids. Thus, theoretically, if all the air voids were eliminated from an HMA sample, the combined specific gravity of the remaining aggregate and asphalt binder would be the theoretical maximum specific gravity.
Which property is most important for asphalt binder?
Durability
Typically, the most important physical properties are: Durability. Durability is a measure of how asphalt binder physical properties change with age (sometimes called age hardening). In general, as an asphalt binder ages, its viscosity increases and it becomes more stiff and brittle.
What is difference between GMM and GMB?
The difference between Gmm and Gmb is volume. The weights are identical. The difference in volume is the volume of air in the compacted HMA mixture.
How do you calculate GMM?
Gmm = maximum specific gravity of paving mixture (no air voids) Pmm = total loose mixture = 100% Ps = aggregate, percent by total weight of mixture (P1 + P2 + P3 + Pn) Pb = asphalt, percent by total weight of mixture. Gse = effective specific gravity of aggregate.
What is the binder used in asphalt?
Typical asphalt binders used in the U.S. are AC-10, AC-20, AC-30, AR-4000 and AR-8000. Viscosity grading is a better grading system but it does not test low temperature asphalt binder rheology.
What are the gyration numbers used in the Superpave Gyratory Compactor?
The Superpave gyratory compactor establishes three different gyration numbers: 1. Ninitial: The number of gyrations used as a measure of mixture compactability during construction.
What is hmhm-685 Superpave Gyratory Compactor?
HM-685 Superpave Gyratory Compactor by Pine Instruments prepares hot-mix asphalt specimens for Superpave mix design operations, and is made in the USA. A mold with asphalt specimen is gyrated on its longitudinal axis at a fixed angle while the end platens are held parallel.
What are the gyrations and compaction pressure settings on the X-ray?
Total gyrations can be selected from 0 to 999 at 30 ±0.5 gyrations per minute and 0° to 1.50° internal or external angle, with compaction pressure selectable from 200 to 999 kPa. The final specimen height is user-controlled from 0 to 200mm.
How does Superpave select its asphalt binder?
Superpave uses its own asphalt binder selection process, which is, of course, tied to the Superpave asphalt binder performance grading (PG) system and the (necessary) associated specifications. A Superpave performance-graded asphalt binder is selected based on the expected pavement temperature extremes in the area of intended use.
