AS 2008 · Class 170
C170 paving bitumen
The default paving grade across Victoria, Tasmania and southern NSW. Softer at low temperatures, excellent crack resistance for cool climates and lighter traffic.
From the Hume Highway to a station track in the Pilbara, bitumen holds this country together. This is the definitive Australian guide — built for engineers, contractors, councils and property owners specifying bitumen for our climate, our standards and our distances.
Bitumen is a thick, sticky, black hydrocarbon — the residue left behind when crude oil is distilled. At Australian ambient temperatures it behaves like a dense solid. Heated above 150°C, it becomes a glossy fluid capable of binding aggregate stones into the surfaces we call asphalt and sprayed seal.
Chemically, it is a colloidal system: high-molecular-weight asphaltenes dispersed through a lighter oily phase of maltenes (resins, aromatics and saturates). The ratio between these fractions determines whether a binder behaves as a flexible coat for a Tasmanian back road or a tough, deformation-resistant surface for the Bruce Highway in Far North Queensland.
“Roughly 85% of Australia's sealed road network — close to 360,000 kilometres — is bound together with bitumen.”
In Australia the words bitumen and asphalt are often used interchangeably in the field, but in tender documents and engineering specifications they are distinct: bitumen is the binder, asphalt is the engineered mixture of bitumen and mineral aggregate that becomes the road surface itself.
Australian Standard AS 2008 classifies paving bitumen by viscosity at 60°C. These are the grades you'll meet on a tender document anywhere from Hobart to Karratha.
The default paving grade across Victoria, Tasmania and southern NSW. Softer at low temperatures, excellent crack resistance for cool climates and lighter traffic.
Australia's national workhorse. Specified for hot-mix asphalt in NSW, QLD, WA and northern climates where heavy axle loads and summer heat demand a stiffer binder.
The hardest standard grade. Reserved for tropical North Queensland, the Top End and industrial pavements in Port Hedland and Gladstone where deformation under heat is the primary risk.
Bitumen blended with SBS polymers or Australian crumb rubber. Specified for the M1, M2, M5 motorways, Western Sydney Airport runways, and heavy intersections nationwide.
Microscopic bitumen droplets suspended in water. Sprayable cold, used for tack coats, micro-surfacing and seals on the long, lightly trafficked rural roads typical of regional Australia.
Bitumen thinned with kerosene-range solvents to reduce viscosity at ambient temperature. Restricted under VOC controls but still used for primer seals on unsealed pavements before sealing.
Australia is the world's biggest user of bituminous sprayed seal. The choice between a seal and an asphalt mix shapes most road decisions in this country.
Hot bitumen sprayed directly onto a prepared base, immediately covered with crushed aggregate, then rolled in. The country roads, the council back streets, the rural highways — most of Australia's sealed network is built this way.
Bitumen and graded aggregate mixed in a plant at 150–180°C, trucked to site and paved while still hot. Smoother, quieter, longer-lasting — and the obvious choice for urban arterials and high-traffic surfaces.
Australia consumes around 4.5 million tonnes of bitumen each year. Roads dominate — but a quarter shapes Australian cities in less obvious ways.
Hot-mix asphalt, sprayed seals and stabilised bases. Australia maintains around 877,000 km of road, of which roughly 360,000 km are sealed with bitumen-bound surfaces — the Hume, Pacific, Bruce, Stuart, Great Eastern and every state network in between.
Oxidised and SBS-modified torch-on membranes waterproof flat roofs across Australia — warehouses in Western Sydney, shopping centres in Melbourne, apartment buildings on the Gold Coast. Self-adhesive systems are increasingly common in residential applications.
Bituminous sheet membranes protect basements, retaining walls, bridge decks and below-ground structures from water ingress. Common across Australian commercial construction and infrastructure projects nationwide.
Polymer-modified bitumen is mandatory at major Australian airports. Western Sydney International, Brisbane's parallel runway, and resealing works at Melbourne, Perth and Cairns all rely on PMB to handle heavy aircraft loads and Australian thermal cycling.
Iron ore in the Pilbara, coal in the Bowen Basin, lithium in WA — Australian mining haul roads use heavy-duty asphalt and sprayed seal to handle the world's largest mine trucks operating in some of the world's harshest conditions.
Australia spans tropical, arid, temperate and cool-temperate zones. Pavement surface temperatures swing from below zero on a Canberra winter morning to above 70°C on a Pilbara summer afternoon. Grade selection follows the climate.
| Zone | Cities | Grade |
|---|---|---|
| Tropical | Darwin, Cairns, Townsville, Broome | C600 / A35P |
| Arid | Alice Springs, Kalgoorlie, Mt Isa | C320 / A20E |
| Subtropical | Brisbane, Gold Coast, Bundaberg | C320 / A15E |
| Temperate | Sydney, Perth, Adelaide, Newcastle | C320 |
| Cool temperate | Melbourne, Canberra, Ballarat | C170 / C320 |
| Cold | Hobart, Launceston, Alpine NSW/VIC | C170 |
Australia produces some of its bitumen at the Geelong refinery, but most is imported through specialist terminals in every mainland state. A handful of producers, modifiers and contractors dominate the supply chain.
Listed for reference only. Bitumen Australia is independent and is not affiliated with any supplier above.
Five documents govern almost every Australian bitumen specification. Anyone writing a tender or accepting delivery should know them by number.
| Property | Typical value | Notes |
|---|---|---|
| Density | 1.01 – 1.06 g/cm³ | Slightly heavier than water; sinks in standard hydrostatic testing. |
| Penetration (25°C) | 40 – 80 dmm | Depth a standard needle penetrates under 100g for 5 seconds. |
| Softening point (R&B) | 46 – 56 °C | Temperature at which a steel ball passes through a bitumen ring. |
| Viscosity (60°C) | 170 – 600 Pa·s | The defining property for the Australian C-grade classification. |
| Flash point | ≥ 250 °C | Minimum required for safe handling under AS 2008. |
| Solubility in toluene | ≥ 99.0 % | A purity check for carbene contamination. |
| Ductility (25°C) | ≥ 100 cm | Stretched at 5 cm/min before breaking. |
| Spray application temp. | 160 – 180 °C | Typical Australian sprayed-seal binder temperature at the spray bar. |
For a fossil-derived product, bitumen has unusually strong recycling credentials in Australia. Most of what comes off our roads goes back onto them.
Australia recovers virtually all asphalt milled from existing roads. Reclaimed Asphalt Pavement (RAP) is reincorporated into new mixes at typical rates of 15–30%, with leading projects exceeding 50%.
Australia generates over 50 million end-of-life tyres a year. Crumb rubber from these tyres goes into modified bitumen, supported by Tyre Stewardship Australia, and now surfaces highways in every state.
Warm-mix asphalt — produced at 110–130°C instead of 160–180°C — is increasingly specified by Australian agencies. It cuts production emissions by around a quarter while meeting the same AS 2008 binder requirements.