white exec wrote: ↑
22 Aug 2017, 08:52
Potholes are virtually unknown here in Spain, despite temperature extremes (and rainfall in the north) that exceed anything found in Britain. Occasional patch repairs seem to last indefinitely, and don't fall out soon after they're put in.
Tell me that the tarmac in the UK isn't substandard stuff, eagerly sold and agreed on by all the manufacturers - a fabulous and incessant source of income from cash-strapped local authorities. I've watched Spanish road repair guys at work, and I can tell you their level of preparation and skill is nothing special, but I'm guessing the black stuff is. One for the Public Accounts Committee, maybe.
It's the same in New Zealand Chris - there are the odd potholes here and there but nothing like the epidemic proportions in Scotland - which are large both in size and in numbers.
I know that salt and freezing cycles often get the blame but I don't buy it. It's got to be a combination of the material used and the propensity to always just "patch patch patch" until you have patches on patches, rather than just rip up the top few inches and re-lay it wholesale.
Here in Scotland at least the roads get dug up constantly to lay pipes with no apparent communication between different interested parties such as water, sewage, gas, cable TV or electricity companies. No sooner is one conduit buried with a patch of seal and another strip is being cut out by a digger for something else nearby. Soon enough the roads (and the pavements!) look like they have been strip mined and hastily filled in.
All of these joins in the surface must surely work loose with the constant application of force by heavy vehicles, and once there is a small crack that water can get into and freeze the crack will expand. But I hasten to point out that these freezing cycles can only get a foothold if the surface is broken to begin with, the water can't magically get below the surface of a smooth piece of road!
Another possible factor is poor drainage causing subsidence leading to cracking. Again, road drainage is really poor here in Scotland. There is no split camber on most roads, (with a slight peak in the middle to help get the water to both sides) no troughs at the side of the road to help channel water along into the storm water gratings, and when it does find its way to them they are blocked and overflowing. In my area I see the same drains flooding out onto the road every time it rains more than a smidgen - year after year. Nothing ever gets done about it.
Contrast this to the roads in New Zealand - nearly all roads are apexed with a slight rise along the white line and a definite slope towards the gutter on either side to prevent build up of standing water on the road surface, the curb is much higher than UK curbs with a trough line depression along the edge of the road, together forming a very effective water channel along the edge of the road, and the storm water drains seem to have a much greater capacity.
It rains less frequently in NZ but there is about twice the monthly rainfall in mm so when it does rain it rains at least 4x harder than the drizzle we get in the UK, and is sometimes a tropical downpour, and yet the storm water drains on the side of the road rarely get overwhelmed.
The road surface itself is almost always bitumen tarmac rather than the hard stuff they seem to use here in the UK. Ironically this can be a problem in summer as it's not unknown for the bitumen to become sticky on a very hot summer day!
I would have thought bitumen tarmac would be ideal here in the UK with slightly cooler temperatures, and I have seen it used in some places like new stretches of motorway like the new M8, but it is rarely used on city streets where potholes are a menace.
Finally in NZ there seems to be a mentality of just rip it up and resurface it rather than just wait and let it crumble and then grudgingly fill potholes with patches as cheap as you can. I remember the main road near where I used to live was ripped up and completely resurfaced 3 times in about 10 years that I lived in the area, and each time they did it the surface of the road seemed fine to me before they started replacing it! They would replace a section about 500 metres long at a time and get it all done in a couple of weeks and without too much disruption to traffic. Pretty proactive really.
And in cases where there was significant construction work being done to lay new pipes etc there might be a temporary patch on for a few weeks but like clockwork a road gang with a roller etc would come along and resurface the entire road width along the affected area rather than leave it as patches.
Like a lot of other urban decay, you'll only ever get high quality roads if you are proactive about maintaining them and replacing them rather than being reactionary and waiting until you get complaints from motorists who are breaking wheels on potholes...
Many roads in the UK are unfortunately at what I would consider 3rd world standards... it does vary a lot with area though - some more northern parts of Scotland towards the Highlands do seem to have much nicer road surfaces than around my bit...