Potholes: the cause

[661-Pete]

Well the BBC has been quick to come up with an in-depth explanation as to why the new spate of potholes have appeared:
http://news.bbc.co.uk/2/hi/uk_news/magazine/8453969.stm
Fair enough. But I have a different theory. It is that the road - paradoxically - overheats when someone gets stuck in the snow and spins their wheel uselessly for minutes at a time. Overheating means the tar melts - and - pothole! Does this sound plausible to you - as an alternative?

Whatever ... I was a bit disappointed by a feature on BBC local news last night, going into the plight of motorists who have dented their supa-dupa alloy wheels on potholes. And not a word of mention of cyclists or other vulnerable users. A dented wheel is - well a dented wheel, a few tens or hundreds of pounds spent on repairs. A dented cyclist is - well it could be months of pain, crippling injuries and off the bike indefinitely.

 

[Norm]

Overheating means the tar melts - and - pothole! Does this sound plausible to you - as an alternative?

Not at all, I'm afraid.

The tyre will only be spinning if it is on snow or ice. Almost as soon as it touches tarmac, it will stop spinning. If there was any heat involved, the tyre would melt and shred, or at least smoke significantly, long before the tarmac got hot enough to melt.

To melt tarmac would require temperatures well over 50c. That would need more rubber than you would get in one tyre.

Completely impossible, IMO.

But I completely agree with the second half.

 

[gaz]

looks like the bbc got it spot on with how potholes are made.

 

[rogersavery]

to get heat you need friction

if you had friction you would not be stuck

 

[Tollers]

Also worth noting that HGV accelerate potholes too. Especially on thin tarmac and patches.

 

[psmiffy]

Not at all plausible - Most potholes in the road are repeat business

Previous pothole was probably repaired using a cut back black pothole repair - not as good as the hot equivalent - water gets into the surface and freezes - heaves - heaves enough times and traffic starts to degrade the patch until it totally fails

New potholes a similar process happens - black part of road gets time expired - subgrade gets overstressed - movement - then cracking - water gets in - get pumping when its warm - frost heave when its cold - black starts to disintegrate - pothole appears

A bit simplistic - but roads only last a certain amount ogf time - if they are not properly maintained then ..................

 

[psmiffy]

And while I am on the subject

A lot of urban potholes are the result of poor infilling of trenches formed by service utilities - electricity, water, gas etc

installing services neccitates digging a trench - damages the sub -grade and unless the subgrade is replaced properly it will fail quite quickly - get movement - cracking - water in - surface starts to deteriorate etc. etc

 

[Trevrev]

There's no getting around it. Thats deffo how potholes are caused.
Thats why so many appear over night on very cold winters nights !!!! Spooky !!
But it's not rocket science.LOL.

 

[661-Pete]

Ah well: so my bright turns out to be a ....

I clearly remember the aftermath of 1962-63, the Big Freeze, when the roads were in a parlous state for months afterwards. It was the time when I - aged 12-13 - first did a bit of serious cycling around the countryside. I can certainly recall denting the wheels a few times (on my cheap kid's bike), though I don't remember having an 'off' due to a pothole.

But take care folks! Today we had a fresh 2" covering so I used Shanks's Pony and potholes weren't an issue - but when I get back on the bike...

 

[marinyork]

Three extremely large potholes - 6ftx3ftx1 inch have appeared on a newly surfaced A road here. Btw if you go out about 10pm at night in the winter and its one of the few areas to get a frost you can see very clearly how potholes form.

 

[psmiffy]

Three extremely large potholes - 6ftx3ftx1 inch have appeared on a newly surfaced A road here. Btw if you go out about 10pm at night in the winter and its one of the few areas to get a frost you can see very clearly how potholes form.

Poor workmanship? - what was the weather when it was resurfaced

 

[Will1985]

Looks like freeze-thaw action at work - geography lessons aged 9 IIRC.

 

[Crankarm]

Not helped by the volume of vehicles using a road pounding the surface and enlarging holes as they appear. Vehicles being driven aggressively and too close making pot holes a dangerous and sometimes unavoidable hazard .

 

[Davidc]

How they form may be interesting but how fast they get repaired wil be more interesting.

As soon as I'm on the bike again (after the thaw) I'll get logging them here:

http://www.fillthathole.org.uk/hazards/report

then at least injured cyclists have a better chance of getting compensation!

 

[marinyork]

Poor workmanship? - what was the weather when it was resurfaced

I would think poor workmanship. Road repairs have been contracted out under a PFI type scheme and had other complaints. One thing I didn't work out though was why they were resurfacing some roads the last year or so, not putting on a top layer, leaving them a few months and then putting it on (and it then wore down very quickly).