The smell of fresh tar in the evening

[nowster]

A side road local to me has recently been taken down to the base layer (loose stones) and been completely remade. Unusually the council has specified Hot Rolled Asphalt (HRA) instead of the more usual Stone Mastic Asphalt (SMA).

Here's your pin-up shot.

[M19]

Looks lovely and smooth and should last at least twice as long as that horrible SMA stuff.

And by using SMA over the last couple of decades we wonder why we have a pothole crisis?

I think the answer is obvious.

[KeithW]

Same thing is happening near to me on Stokesley Road , Marton-In-Cleveland , they have basically taken it back to the sublayer and have closed the road overnight to lay a new surface.

[fras]

Looks lovely and smooth and should last at least twice as long as that horrible SMA stuff.

And by using SMA over the last couple of decades we wonder why we have a pothole crisis?

I think the answer is obvious.

Yet the Germans, who invented SMA, manage well with it as anybody who has driven in Germany knows. Their roads are like billiard tables and potholes very rare. It has to be something to do with how we produce SMA. Maybe the Germans need to show us how.
Of course, HRA does last and last. There are some heavily trafficked roads, (HGVs et al) near me that were surfaced with HRA well over 30 years ago and are only now needing attention. I suspect it is councils that seem to think they don't need any highways engineers and can leave it all to the contractors.
Have read here: -
https://web.archive.org/web/20160304085 ... nance.com/
The site is no longer maintained and updated, as I suspect Mr Summers has either died or given up in disgust.

[skiddaw05]

HRA can be prone to rutting though, whereas the stiffer SMA tends to keep its shape better.

I've mentioned elsewhere that Highways England (to the best of my knowledge) don't use the German SMA spec instead opting for a spec with a lower binder content due to concerns about the (initial) lack of skid resistance of a more binder rich product. But this also makes it less durable which leads to the problems of the surface breaking up and creating potholes.

Another issue which has lead to various highways authorities choosing SMA over HRA is a practical one - the machine needed to lay the chippings into the HRA is wider than the paver so this can lead to the road having to be closed whereas with SMA (which doesn't need a chipping machine) the work could be done under single way working with the road kept open, depending on the width of the road of course.

[fras]

The lack of grip for vehicles when SMA has just been laid caused a row in Ireland, where the roads are rather more subject to rain than elsewhere. (Irish weather forecast "Its raining" or, "its going to rain"). This experience and no doubt elsewhere for new SMA users seems to have caused a change to use of less binder, (the bitumen !). I do wonder how the Germans get over this characteristic. Maybe they have some sort of scraper device that runs over the new surface to put some grip into it. Whilst I've been to Germany very regularly since 2008, I have yet to see a German road gang at work laying SMA.

[Bendo]

Probably like anything really, do a decent job and it will last. Do a rubbish job and it won't. Halton Council had the A557 Watkinson Way done with dreaded surface dressing a few years back and it seems to have been done to a decent standard and is still fine. On the flip side they did Lunt's Heath road 6 months ago and must have had it done as cheaply as possible as it's already come up in lots of places and is just a mess now.

[CallumParry]

I will always swear by HRA as the best surface however I know some hate it but some areas of the SRN i'd welcome back concrete as a more rigid hard wearing surface.

[ABB125]

I will always swear by HRA as the best surface however I know some hate it but some areas of the SRN i'd welcome back concrete as a more rigid hard wearing surface.

Has anything come of the trials Highways England were supposedly carrying out to improve/make quieter concrete surfaces (possibly using some sort of grinding technique that is commonplace in the USA)?

[Conekicker]

Mmmmm the smell of hot bitumen - lovely.

[DavidB]

I was in Ireland in June 2005 when the southern section of the M50 opened and a couple of days later I drove on it. It was a warm evening, I had the window down and the sweet smell of new tarmac was amazing.

[skiddaw05]

Mmmmm the smell of hot bitumen - lovely.

Rivalled only the the aroma of fresh thermoplastic!

[traffic-light-man]

Mmmmm the smell of hot bitumen - lovely.

Rivalled only the the aroma of fresh thermoplastic!

I was on site the other day while the white lining was going down and that was a good smell that I don't think I'd particularly noticed before. Not sure it quite beats fresh asphalt for me, though.

[yen_powell]

The hissing noise of light rain onto a freshly laid road as the water boils off. Like rice crispies!!