Stabiliser picks for Australian ground conditions: a practical guide for WR machine operators
Stabiliser picks take a different kind of punishment to milling picks. Where cold milling machines cut through relatively consistent asphalt at controlled depths, stabilisers work through subgrade material that can include clay, gravel, rock, lime, and bitumen emulsio often in the same pass, and often in conditions that vary significantly from one project to the next. Getting the right pick for your ground conditions makes a real difference to wear life and cost per kilometre.
Shank compatibility: 22mm and the HT11 and HT22 holder systems
PPA’s stabiliser picks use a 22mm shank, compatible with both the HT11 and HT22 quick-change toolholder systems found on Wirtgen WR series machines. If you’re unsure which holder system your drum runs, send us your machine model and we’ll confirm compatibility before you order. PPA stocks two 22mm picks covering standard and heavy duty stabilisation conditions.
PPA6HS/22 standard conditions
The PPA6HS/22 carries 30.8g of virgin tungsten carbide with a pointed tip geometry. It’s the standard pick for most stabilisation and cold recycling work cutting efficiently through road base, granular subgrade, lime-treated material, and bitumen emulsion mixes in typical conditions. For the majority of Australian stabilisation projects on granular or clay subgrades, this is the right pick.
PPARZZ22/22 heavy duty conditions
The PPARZZ22/22 carries 50g of tungsten carbide in a larger flat top tip configuration more than 30% greater carbide wear resistance than the PPA6HS/22. It’s built for high-power machines working in abrasive conditions: rocky or gravelly subgrade, calcrete, highly weathered rock, and material with significant hard inclusions. If your projects involve the kind of ground conditions common in the Pilbara or Goldfields, the PPARZZ22/22 is the right choice.
Australian ground conditions and pick selection.
Australia’s geology varies significantly across regions, and Western Australia in particular presents a wide range of stabilisation challenges. Understanding what you’re cutting through is as important as knowing your machine spec.
Coastal plains: Perth metro and surrounds
The Perth coastal plain is dominated by deep, permeable Bassendean and Spearwood sands. These cohesionless granular subgrades offer good drainage but lack shear strength and can rut under load. Stabilisation typically involves bitumen emulsion or foamed bitumen mixed in-situ to bind the granular material. In these conditions the PPA6HS/22 performs well, the material is abrasive but not particularly hard, and the pointed tip cuts efficiently through emulsion-treated sand.
Wheatbelt and inland regions
Expansive, highly plastic clays dominate the Wheatbelt and much of inland WA. These soils shrink significantly when dry and swell when wet, causing volumetric instability and pavement heave. Lime stabilisation is the primary treatment quicklime is mixed in to cause a cation exchange that flocculates the clay particles, reducing plasticity and increasing bearing capacity. Projects in these areas typically follow Main Roads WA Specification 515 for in-situ stabilisation. Pick wear in lime-treated clay is generally moderate the PPA6HS/22 handles this application well.
Pilbara, Goldfields, and hard rock regions
Iron-rich residual soils, calcrete, and highly weathered rock characterise much of the Pilbara and Goldfields. These materials are significantly harder and more abrasive than coastal or clay subgrades, and stabilisation for heavy haulage roads in these regions puts much higher demands on picks. The PPARZZ22/22 is the appropriate choice here the additional carbide mass and flat top geometry handle the impact and abrasion loading better than a standard pointed tip pick in these conditions.
Quick reference: which pick for which conditions
- Standard stabilisation, granular or clay subgrade, coastal or inland WA → PPA6HS/22
- Lime stabilisation, Wheatbelt or rural clay subgrade → PPA6HS/22
- Rocky, calcrete, or highly abrasive subgrade, Pilbara or Goldfields → PPARZZ22/22
- High-power machine in tough mixed ground conditions → PPARZZ22/22
Not sure which pick suits your project? Send us your machine model and a description of the material you’re working through and we’ll give you a straight answer.
PPA picks are aftermarket products and are not manufactured by or affiliated with Wirtgen or any OEM. Always verify shank diameter and holder specifications match your machine before ordering.
