Concrete motorway sections - why?

[TTmonkey]

Why are some small parts of the Motorway system surfaced with concrete, as apposed to the majority of the motorways being laid with tarmac?

Is there a technical reason why some small stretches are concrete? Its harsh, noisy, usually bumpy. And I suspect grip levels are less. Its probably harder to lay also, so why is there some sections that are always concrete?


Always wondered why.

[andy-xr]

M42 to M40

Shudder

I used to drive that section a lot and hate it

[KTF]

I suspect its cheaper and/or deemed to be in an area where the noise it generates is less of an issue.

[Matt UK]

I think it is more durable to heavy loads.

[littleredrooster]

IIRC, it was a 1960s experiment. The M6 throught Lancs and Staffs used to be concrete sections with expansion strips and it seemed to be un-wear-outable, but lethal in the wet or snow; water settles on the surface and has nowhere to go.

Edited by littleredrooster on Friday 4th October 16:11

[MarJay]

Concrete lasts twice as long and costs half as much as asphalt, but it makes more noise so it can't be put near residential areas.

[XAF]

It's also used in areas that may be susceptible to subsidence. Tarmac and hardcore will 'bend' and sag more than concrete. Some roads are made in concrete the covered in a thin veneer of Tarmac to reduce noise near residential areas. Both of these factors resulted in the patchwork that is the A1/M1 link road near Leeds

[hidetheelephants]

Concrete was cheap and quick to lay, which was deemed a 'good idea' when the UK was building her M-way network. The problem is that it's a bit ste as a road surface and almost impossible to repair once it starts falling to bits, so you have to rip it up and start again; IIRC attempts to just lay asphalt over the top failed quickly and spectacularly in some instances.

[droopsnoot]

andy-xr said:

M42 to M40

Shudder

Not just me then. The start of the A50 heading east out of Stoke is pretty bad, but the section of M42 just before the M40 turn-off seriously had me wondering whether I had two punctures.

[harlowhammer]

Flipping A12 so noisy

[jagracer]

When the A20 Swanley bypass was first laid in the 60s they put ripples in the concrete, presumably to get rid of water and it was so noisy the local residents couldn't sleep. It had to be relaid shortly after but It's still concrete and still noisy.

[DonkeyApple]

hidetheelephants said:

Concrete was cheap and quick to lay, which was deemed a 'good idea' when the UK was building her M-way network. The problem is that it's a bit ste as a road surface and almost impossible to repair once it starts falling to bits, so you have to rip it up and start again; IIRC attempts to just lay asphalt over the top failed quickly and spectacularly in some instances.

Wasn't there also a Cold War military aspect when the motorways were built that meant they would also be core arteries for movement when the Russians landed and so needed to be able to handle tank transports?

I think that nowadays it is used in special situations to do with either compression situations or where steel is involved?

[skyrover]

Well laid quality concrete is superior to asphalt in many areas such as durability and grip.

I emphasis the "well laid" part

[Dogwatch]

Motorways were built by different contractors each doing a length. Some contracts were won by contractors who bid on the basis of doing their 'bit' in concrete. Other contractors specified tarmac.

No mystery really.

[Chris Stott]

M42 is a POS... the surface is absolute ste

[saaby93]

skyrover said:

Well laid quality concrete is superior to asphalt in many areas such as durability and grip.

I emphasis the "well laid" part

Isnt it that concrete tends to stay flat, Tarmac formed into parallel depressions where HGV wheels run causing tramlines and standing water/ice

[clarkey540i]

I have to say that concrete roads seem to be in much better condition than tarmac ones. I suspect that this is because concrete is less porous, preventing potholes forming from water expansion in winter.

[Huff]

OTOH concrete road surfaces tend to beome a bit too polished, and settle unevenly ('thump, thump, thump, thump...') whereas tarmac doesn't - the bitumen binding component wears down faster than the rough stone, so remains grippier for longer.

I seem to recall (hating) the M11 when it was all conc simply because the wear-ruts in lane 1 were profound. Then again, at the time I had a powered-up Mini with some interesting geometry...

[B17NNS]

droopsnoot said:

The start of the A50 heading east out of Stoke is pretty bad

Stoke (Blythe Bridge) to Uttoxter, like one long bloody rumble strip. Not an old road either, built in the 80's I seem to remember.

[mrtwisty]

B17NNS said:

Stoke (Blythe Bridge) to Uttoxter, like one long bloody rumble strip. Not an old road either, built in the 80's I seem to remember.

Yep, bloody deafening at high speed!