A performance test in which a steel wheel carrying about 158 pounds rolls back and forth over compacted mix specimens submerged in hot water, commonly 50 C, for up to 20,000 passes. The rut depth at the end shows resistance to permanent deformation, and a sudden steepening of the rut curve, the stripping inflection point, reveals moisture damage. Agencies set pass limits, often 12.5 mm of rut at a pass count tied to binder grade.
Hamburg hit 12.5 at 14,000 passes, mix needs anti-strip or a stiffer binder before it goes on the interstate.
Also heard as
- Hamburg
- HWTT
- Hamburg wheel tracker
Related terms
Rutting
Channel-shaped depressions that form in the wheel paths as the pavement deforms under repeated loads.
Stripping
Loss of the binder's bond to the aggregate surface, caused by moisture working into the mix.
TSR
Tensile strength ratio: a moisture-damage test comparing the strength of soaked mix specimens to dry ones.
Puck
Lab slang for a compacted cylindrical mix specimen, especially one made in the gyratory compactor.