I would guess that the mechanism of action is that water gets through the cracks and erodes the underlayment.
In my experience, both.
Set aside for one moment this new roller, the reality is that road paving is not exact science, and - even if it was - it is largely executed badly.
Paving (and before paving the underneath layers) are more like "cooking" than everything else.
It is not like you have the right recipe, good ingredients and follow "instructions" accurately you can replicate some dishes.
Usually (of course it greatly depends in local uses and materials available) the first mistake is under-calculating the thickness and consistence of the bottom layers (gravel, sand, quarried rubble, sometimes mixed with cement or lime).
The second one (again usually, not always) is inadequate protection from running water (be it coming from rain or from the soil).
Then it comes the exact composition of the asphalt, the (right or wrong) type and quantity of bitumen, the temperature at which it is mixed, transported and layered, the amount of compacting, etc., etc.
In the last 20 years or so some great betterings have come from the use of reinforcing layers, both in the underpavement (woven or non-woven geotextiles) and in the asphalt itself (geogrids, usually plastic).
Whilst geogrids in asphalt are rather costly (both as material and additional work to lay them), high strength geotextiles are relatively cheap and it is surprising how - still today - they are not widely and universally used.
Both however are only good for highways and roads outside the city, as the benefit of these textiles is to spread as much as possible any dynamic action provoked by heavy traffic and loads onto the widest possible surface, but in urban contexts the surface (and up to 1-1.5 m depth) is "ruined" by every kind of duct, pipe, cable and other services, often re-cut (over and over) for maintenance/repair/replacement.
You can impact road surface wear by tweaking any of these variables. They all affected the surface, there is no single cause.
Back 35 or 40 years ago, Phillips petroleum was promoting a paving material that supposedly solved this problem. Where is it?
There may be single causes, we just need them all to marry single solutions.
Also, asphalt isn't solid, it get thinner when the sun is high, deforming every time a car runs over it in the summer.
South of south America, more or less equivalent to Florida: no freezing during winter and not that hot during summer, but everytime there's many rainy days, holes will appear. Get few days of hot sun and the roads will deform a bit, specially where trucks and buses run over.
Are you calling North America "America", and then go on and call Florida "south America", as if there isn't such a place in the world as South America? I do not approve of this North America-centric view of the world at all.
Depending on the geography class you took, and where, there might not be a "South America". Some countries just call the whole continent America:
Most North Americans are taught that there are 7 continents: Asia, Africa, North America, South America, Antarctica, Europe and Australia/Oceania. In some textbooks, North and South America are combined into "America" and/or Europe and Asia are combined into "Eurasia", for a grant total of 6 or even 5.
I do not approve of your 7-continent view of the World, as if it was the only one.
Culturally? Really? What's so different culturally between Colombia, Argentina, Paraguay, Chile, and say, Panama, Nicaragua, Guatemala Costa Rica to warrant each set belonging to another continent?
Sometimes languages use the same name for different things, and people can trivially disambiguate from context.
"In the southern part of South America, more or less equivalent to Florida", probably referring to the southeast side of that continent.
This map indicates that areas of Argentina's, Uruguay's, Paraguay's, and southern Brazil's climates would fit the description of "more or less equivalent to Florida": https://upload.wikimedia.org/wikipedia/commons/1/1e/World_K%...
The southern part of South America, a similar distance from the equator as Florida.
I don't approve of getting upset over turns of phrase online. Principle of charity.
Well, that might be true for people living in the US but, and I might be going out on a limb here, it might not be so true for others.
And for a comment referencing Florida, is it charitable to apply something for continents to your stated interpretation? Principle of charity says not.
Specifically who refers to America/Americans in English as meaning "People who live on the continents in North and South America"? Lets hear names not an allusion to "others".
I'm only aware of a rather vocal minority of South American students recently getting angry at the term America being attributed to citizens of the USA. But its really no different from my aforementioned Mexico example in Spanish. Their category error is trying to redefine America from its shorteneed form for USA, to some super continent association of "America". But it goes against a lot of existing usage in not only English, but other languages. [1]
I respect that you have a position here, but frankly its a silly way to try to redefine the word America as its been spoken in English for a long time to refer to a super continent of both North and South America.
Example Portuguese, America refers to the USA, and to both Continents, aka like in English have to figure out the context: http://www.wordreference.com/enpt/america
French, pretty much the same, only the continent is generally called out separately as continent américain: http://www.wordreference.com/enfr/america
German, closer to French/English here but separate in that they tend to refer to the "americas" as north middle and south america, which is in many ways more appropo: https://dict.leo.org/englisch-deutsch/america
Japanese, i'm not as qualified with my 3 months of learning japanese to comment on this but given the Kanji in use they're already separated: https://jisho.org/search/america
Etc...
Also are you saying that all of the societies and engineering societies such as The American Society of Engineers should be required to change their name as they don't allow people from Canada, Central America, and South America to join? At a certain point I just can't find this position on the word America to make sense. Its just a weird thing to die by the sword on.
USA is a terrible name, it could equally apply to any country, Canada say, in the American continent formed from multiple states.
It is wrong to call societies only for USAmericans "The American ...". The whole thing supports the idea that the only Americans worth bothering with are USian, it's extremely pompous and self-agrandising.
You should get a proper name.
Perhaps if things work out in Korea they'll call themselves the United States of Asia ...
Re Mexico, there's no continent called Mexico, no ambiguity or appearance of narcissism attaches to not using the full title. It's not at all equivalent.
America is not a continent, its two continental plates roughly separted at Panama via the Carribbean plate. Can you point me to a recording of someone using this terminology in real life? USAamerican is pronounced as ooh sa American or what? I can't see this catching on. Or oooh ess ian either. I doubt the Canadians want to get lumped in as Americans even under this nouveau definition.
> USA is a terrible name, it could equally apply to any country, Canada say, in the American continent formed from multiple states.
But it isn't that at all, which segues into:
> Re Mexico, there's no continent called Mexico, no ambiguity or appearance of narcissism attaches to not using the full title. It's not at all equivalent.
I was using that as a parallel in that we don't call mexico by its republic name.
Words can have multiple disparate meanings, America tends to have indicated a shortening of The United States of America. Do you believe citizens of this country can't name themselves?
You also conveniently omitted what english speaking region you are from so I can't follow up on how wide spread your version of things is/n't.
"USAmerican" - like U.S.A but with American replacing the A. Variations expected.
>America tends to have indicated a shortening of The United States of America //
To people who assume that it's the only place in America that anyone would talk about.
>Do you believe citizens of this country can't name themselves? //
How many current citizens chose that name; I'll go with none. If you asked the question "what should we name our union of states, one of several unions of states in America" I'd hope most intelligent people would think something other than USA was best.
I'm from the UK (which has a lot of stupid naming too, but that doesn't make USA a sensible name, bad naming elsewhere doesn't make this naming better). But for the purposes of this conversation that probably just counts as "not America" by which will be meant "not USA". /s
/rant
> I respect that you have a position here
Thank you. I appreciate you saying so.
> but frankly its a silly way
Yes, I was being silly. But only because if you bundle South America and North America and then go on to call the south of that super-continent "Florida", well, a globalist such as myself has to object.
Fair enough, but it read more as being willfully obtuse if anything.
It seems that 1ms after a clean paved road is down, someone in another dept is plotting to tear it up to get at their utility, then hire 2 guys with a shovel to do a very halfassed patch job afterwards, which either is heaved up high or sunk down low. The halfassed patch will become a pothole for the next 10 years of repatching it badly over and over again.