Tarmac? You mean 'hazardous waste'
Sir, As a jobbing highway engineer, road characteristics researcher and lapsed geologist (who may even have been tutored at one stage by our revered Editor) I must point out to the authors of the
feature 'Cracking up in Lincolnshire' that using words like “tarmacadam” in any report to a highway department will produce shudders and shakes.
'Tarmacadam' is a term for a specific grading of granular material bound with...tar. Tar is a coal-tar derivative, packed full of polycyclic aromatic hydrocarbons (PAHs) - a hazardous waste that is exceptionally difficult to dispose of (and expensive with it).
If you do not know whether a road surface is an asphaltic concrete (not a cement-bound concrete) or a dense bituminous macadam, or indeed a horrid nasty nasty evil tarmacadam, just call it a 'bound layer'.
If you suspect tar, let the highway team know as soon as possible, as a late discovery could have a significant impact on the road building process: a quick test with a PAKMarker pen or spray with rule it out (hopefully).
There still is a lot of tar bound up in old roads but it is not ubiquitous, so “bound layer” and a photo or “asphaltic layer” or “bituminous layer” and the same all float my boat. Yes I know asphalt sits in lakes and caught mammoth and sabre-toothed tigers, and that bitumen is oil derived, but we won’t get picky!
Tar but no tar, thanks!