EVs causing potholes ?

[The Natural Philosopher]

What do you think that f****ng black shit is, then?

[The Natural Philosopher]

Tar IS bitumen.

That's why its called TARMAC.

[The Natural Philosopher]

Well I have never heard that distinction made.

To me 'Tar' is a generic cover all term for extremely thick hydrocarbons. There is no such place as the Athabasca Bitumen sands. They are called the Athabasca *Tar* sands. And they are made of bitumen, or tar.

If you want coal derived hydrocarbons that is *coal tar*. The reason it's called *coal* tar is to distinguish it from *oil* tar...

Tar is a generic word.

[The Natural Philosopher]

I assume you meant switched away from coal tar..

IIRC asphalt is a mixture of tar and ballast...although that apparently is strictly 'asphalt concrete'

Anyway its a side issue. The point is that many minor roads are not made with massive substrates.

[Clive Arthur]

It's a common mistake. Don't beat yourself up to much.

<snipped irrelevant diversionary waffle>

Of course it /can/ be, as are many words used by the layman. However, when pontificating ("MOT type 1, blinded with sand and a inch or two of gravel and tar on top") in a semi-technical newsgroup it's best to be accurate.

[Colin Bignell]

There are, however, differences between coal tar and bitumen that affect their suitability for road surfacing. Coal tar has a higher melting point, but bitumen and bitumen based asphalt give better grip for rubber tyres.

[Colin Bignell]

A reason to visit your GP :-)

[The Natural Philosopher]

It *is* accurate. Tar is not 'coal tar'

[Clive Arthur]

You see, when I queried the common but incorrect use of 'tar' in the context of road construction, what most people (even Speed, sort of, grudgingly) would say something along the lines of, "I didn't know that, interesting."

But a TurNiP can never admit error. Either, like a true Black Knight, he must argue to the bitter end, losing limb after limb, or quietly slink off, never to mention the subject again.

This correspondence is now closed.

[Fredxx]

Coal tar is a tar. Tar includes a wider group of similar products.

>

[The Natural Philosopher]

No, it isn't. I have provided clear evidence that 'tar;' is used generically to apply to any heavy non volatile hydrocarbon.

[The Natural Philosopher]

I am sure there are various differences.

It is however not germane to the issue of how a minor urban or rural UK road is typically constructed.

Many of these are not 'new builds' at all - they are layer upon layer of history..

Back in the 1950s there were many untarred roads. Essentially simply some sort of crushed stone base with sometimes a gravel top.

These got a tar and gravel topping applied at some stage, and that is essentially all they are.

Good enough for horses and carts, and light motor vehicles.

[charles]

but not for the sort of vehicles that turn up at building sites ;-(

[#Paul]

Wikipedia has this:

The fourth power law (also known as the fourth power rule) states that the greater the axle load of a vehicle, the stress on the road caused by the motor vehicle increases in proportion to the fourth power of the axle load. This law was discovered in the course of a series of scientific experiments in the United States in the late 1950s and was decisive for the development of standard construction methods in road construction.[1]

#Paul

[The Natural Philosopher]

Yes. Contact pressure has nothing to do with road deformation.

As usual people are introducing red herrings to distract from the real issue

[Rod Speed]

I didnt say that. I actually said that the turnip was not making a distinction between tar and bitumen and he has now said that very explicity.

He was not making an error, just not making a distinction between tar and bitumen. Even our road engineers do that too, calling it a tar seal when in fact bitumen is used.

Nope.

[Max Demian]

OK. So what is "pitch"?

[Jeff Layman]

From

:"In the early 1970s, when the UK market switched to coal tar, asphalt became a much less popular product and the Government of Trinidad and Tobago took ownership of the asphalt extraction business in 1978."

On the other hand, from

:"However, since the 1970s, when natural gas succeeded town gas, bitumen has completely overtaken the use of coal tar in these applications."

I assume the latter, as you proposed, is in fact correct.

The terminology seems to be quite confused, but this seems useful:

No doubt about that! The geniuses round here, while repairing potholes, managed to remove the drainage ditches at the side of one road. So although the potholes are no longer a problem, the road floods easily in heavy rain.

[Tim Streater]

Well it would have to have done, given that coal tar was a by-product of gas production until natural gas started to be used. In fact quite a lot of chemical feedstock came from such gas production.

[The Natural Philosopher]

It's the frequency of a tone.:-) And a place where sports are played.

"Pitch is a viscoelastic polymer which can be natural or manufactured, derived from petroleum, coal tar, or plants. Pitch produced from petroleum may be called bitumen or asphalt, while plant-derived pitch, a resin, is known as rosin in its solid form. Tar is sometimes used interchangeably with pitch, but generally refers to a more liquid substance derived from coal production, including coal tar, or from plants, as in pine tar.

In short the whole thing is a minefield with both pitch and tar being generic terms, whereas asphalt and bitumen are specifically petroleum products