Gyratory compaction
- A hot specimen receives an axial load while the mould rotates at a controlled angle, combining compression and shear.
- Height or density recorded against gyrations describes how the mixture densifies and helps compare workability.
Applications
- The procedure can support volumetric mix design and quality control, as well as produce specimens for other tests.
- Mass, mould geometry, temperature, pressure, speed, and angle must match the applicable method.
Wheel tracking
- A wheel applies repeated loading to a slab or specimen conditioned at a controlled temperature; the movement accelerates a traffic-like action.
- Rutting depth is measured against passes. Conditioning medium, wheel, and load depend on the chosen procedure.
Interpretation and cautions
- Compare curves and final values only with the specified geometry, temperature, load, and acceptance criteria; do not mix protocols.
- Check parallelism, uniform compaction, and conditioning. Cracks or unrepresentative voids can distort the measured rut.
Density, voids, and permanent deformation
- Compacted relative density: ρb = Mdry/Vbulk; Gmb = ρb/ρw. Air voids: Va = 100 · (1 − Gmb/Gmm), with Gmm measured for the same mixture.
- Density as a percentage of Gmm can be written C = 100 · Gmb/Gmm. Do not confuse it with a percentage of a different reference maximum density.
- Plot Gmb or specimen height against gyration count; use Nini, Ndes, or Nmax only when defined by the design specification.
- In wheel tracking, report rut depth Rd in mm against cycles or passes. The rate WTS = (Rd,2 − Rd,1)/(N2 − N1) is comparable only when the method’s cycle window and definition match.
Educational reference guide. Check the current standard, calculation assumptions, and project specification before applying a procedure or acceptance criterion.