What it is called, by market
One concept, four markets. Where a name means something else locally, the card says so rather than leaving you to find out on site.
United Statesyours
Close, not identicalasphalt
also blacktop, hot mix asphalt, HMA
In American usage "asphalt" names both the BINDER and the finished mix, which is the reverse of British usage where bitumen is the binder and asphalt the mix.
Canada
Close, not identicalasphalt
also blacktop
As the United States, with the same double duty: asphalt is both the binder and the laid material depending on context.
United Kingdom
Same word, different thingasphalt
also tarmac, bitumen macadam, blacktop
"Tarmac" is a trade name for a tar-bound material that is essentially no longer laid — modern surfacing is bitumen-bound — so the everyday British word names the wrong binder.
Australia
Same word, different thingasphalt
also bitumen, hotmix
Australian site usage often calls the finished surface "bitumen", which in British and technical usage is the BINDER rather than the mix — the same word doing a different job.
The governing standard, by market
United States
ASTM D6926 / Superpave
Asphalt mixture design and specimen preparation.
United Kingdom
BS EN 13108
Bituminous mixtures — material specifications.
Calculators for this
Each works in either measurement system, and the terminology on the page follows whichever market you have selected.
Frequently asked questions
- Is tarmac the same as asphalt?
- Not technically, and the difference is the binder. Tarmac is short for tarmacadam — crushed stone bound with TAR, a by-product of coal processing — and it is a genuine historic material that has been almost entirely replaced by bitumen-bound mixtures, because tar is a petroleum-free by-product that became scarce and carries health concerns. What is laid on a British drive or road today is asphalt: the same aggregate idea with a bitumen binder. The word survives in everyday speech, in airport tarmac, and as a trade name, so a client asking for tarmac and a contractor quoting asphalt are describing the same work — but a specification that says tar means something a supplier cannot deliver.
- What is the difference between bitumen and asphalt?
- In British and technical usage, bitumen is the BINDER — the black viscous material that holds the aggregate together — and asphalt is the finished mixture of binder and aggregate. In American usage "asphalt" does both jobs: asphalt cement is the binder, and asphalt or hot mix asphalt is the laid material, with context distinguishing them. Australian site usage adds a third pattern, calling the finished surface bitumen. None of these is wrong within its own market, and all three appear in documents that cross markets — so a specification naming a grade of bitumen and one naming a grade of asphalt may be talking about the same property or about two different layers of the same construction.
- Does the surfacing come in one layer?
- Rarely, and the layer names are another place the markets diverge. A bound surfacing is normally built in courses: a thicker, coarser lower layer that carries the load and a thinner, finer upper layer that provides the running surface and the texture. British practice calls them binder course and surface course, with a base beneath; American practice names a base course, an intermediate or binder course and a wearing or surface course. The materials, the aggregate sizes and the compaction requirements differ by layer, so a thickness quoted without saying which course it refers to is ambiguous — and a drive laid as one thick layer of surface-course material is a different construction from one laid properly in two.