Roads melting

[obi_waynne]

There are a couple of roads down near me that are melting in this hot weather.

The M25 had a stretch closed a few weeks ago due to it melting.

Surely they don't have this problem on the roads through the Nevada desert and death valley?

Do you have melting roads where you are?

 

[old-git]

No, they don't, becasue they use a binder that is suitable for the prevailing conditions, ie always hot.

The problem in the UK is the temperature range, -10 and below to +30 and above. If you specify a bitumen mix that is still pliable at -10 it will melt above 25 or so. If you use a bitumen that doesn't melt at 30 it will crack at -10 or below!

Therefore we tend to use a mix that works 99.9% of the time - meaning there is a chance of melting once every 3 years but doesn't become brittle below -10 which is a far more common occurance.

If you specify too wide a temperature range you compromise the matrerial strength and longevity.

Nothing is ever as simple as politicians, taxi drivers and the uninformed think it is

 

[st24]

No, they don't, becasue they use a binder that is suitable for the prevailing conditions, ie always hot.

The problem in the UK is the temperature range, -10 and below to +30 and above. If you specify a bitumen mix that is still pliable at -10 it will melt above 25 or so. If you use a bitumen that doesn't melt at 30 it will crack at -10 or below!

Therefore we tend to use a mix that works 99.9% of the time - meaning there is a chance of melting once every 3 years but doesn't become brittle below -10 which is a far more common occurance.

If you specify too wide a temperature range you compromise the matrerial strength and longevity.

Nothing is ever as simple as politicians, taxi drivers and the uninformed think it is

Thanks for clearing that up then

 

[old-git]

No problem. Always glad to help on subjects I know a little bit about

 

[T9 man]

No problem. Always glad to help on subjects I know a little bit about

Ok, answer this one for me please OG

Earlier today while outside the Tower Bridge attractions I stood at the pedestrian crossing waiting to cross the road along with our tourist friends.
Now the traffic lights went red and the pedestrian lights went green - so far so good! Then I noticed that the audible beeping sound from the lights stopped exactly as we all reached halfway onto the pedestrian island. Which meant that the final half of the journey across the road was completed in silence but with the pedestrian lights now switched off before it eventually went to red once we got to the other side of the road :blink:

Never really noticed this before OG, but I would have thought that at least for the visually impaired the audible beeps would stay on until the full crossing of the road was accomplished. Is this not a safety infringement OG? :blink:

 

[old-git]

Doesn't sound right, but after 2 bottles of wine who the frick cares?

Maybe the beeping stopping means get your arse in gear, you slow fookers, or you will be squashed.

It's been a stressful day that the wine has helped to numb, so I apologise if I have been harsh - I will try again tomorrow when sober.

Love and peace to all

 

[T9 man]

Take care and sleep well OG

 

[old-git]

Take care and sleep well og

zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

 

[obi_waynne]

I would have assumed that the beeping is a signal "safe to cross" so when it stops there is not enough time to get across the road.

 

[Twamgl3]

I would have assumed that the beeping is a signal "safe to cross" so when it stops there is not enough time to get across the road.

Yep.

And I know that because I used to maintain them and had a hand in programming them a few years back.

 

[Twamgl3]

Not the one's in London, admittedly, but they are all designed to the same specs.

 

[old-git]

I would have assumed that the beeping is a signal "safe to cross" so when it stops there is not enough time to get across the road.

When the beeping stops it means there isn't time to get across if you haven't already started. There is a delay between the beeping stopping and the lights changing to allow pedestrians to complete their journey in safety.

If I remember correctly, there is a system whereby movement detection equipment monitors the crossing and does not let the lights change until it is clear.

 

[turbonutter69]

Not all are like that og... Only the newer ones.

If I remember correctly, there is a system whereby movement detection equipment monitors the crossing and does not let the lights change until it is clear.

 

[old-git]

Not all are like that og... Only the newer ones.

When I retired 3 years ago they were fairly new and the idea was to gradually upgrade all crossings when budgets permitted so I guess it will take some time.

 

[turbonutter69]

Yeah they've replaced a lot round here. They've been out a while but as you say funds will be a big issue.
All the newly installed ones will be of that type though.

When I retired 3 years ago they were fairly new and the idea was to gradually upgrade all crossings when budgets permitted so I guess it will take some time.