Tamacadam

[BertiWooster]

I've seen workmen laying new tarmacadam on roads , when it's raining .

Why doesn't the water affect the tarmacadam ?

[Broken__stoned]

it does Bertie, it makes it wet

[wildwood]

Tacmac is much denser than water so will not mix with it. The temperature is much more important.

[craft1948]

I used to love watching the old steamrollers....

[Broken__stoned]

What The Funicular lol i never had you down for 'easily pleased' crafty

:

[ttfn]

so did I as child craft - always called them 'rolling steams' much to mother's amusement.

[chas2008]

i think im right in saying theres also a certain amount of oil in it and its laid hot so as it dries/rollered it cures

[B00]

I love the smell of newly tarmacced roads.

[jomifl]

why would it? Tarmac doesn't get washed off the road when it rains.

[jomifl]

Its not the density that stops the tar in tarmac from mixing with the water, the molecules that make up tar are hydrophobic a bit like the oils on a duck's feathers.

[gordyagusta]

Tarmacadam is normally 20mm - 6 mm bitumen coated aggregate heated to over 160 degrees centigrade. Then deposited into the back of a tipper wagon which has an insulated body to maintain the heat in the mix. Bitumen as a natural occuring oil based material and is proportionately much more denser than water thus repelling any rain water and the heat built up in the mix helps to evaporate any surface water during the laying of the Tarmacadam.

[scotman]

Joss

I remember when I was a lad watching roads being laid. Any sign of rain and everything stopped.
New methods are possibly the reason why roads in Edinburgh seem to last about 6 months now.

[BertiWooster]

Is the tarmac used on roads of better quality to what's used - on your drive , for example ?
Drives made from tarmac always seem to break up more easily / quickly