This question is for anyone who knows about how our roads get paved (GZire?).  I've been to places like Tokyo, Connecticut, and just came back from a vacation that saw us in Vancouver, B.C. and Seattle where temperatures and weather conditions vary much more than they do here but yet it seems like the roads that I encountered had few if any potholes or bad cracks.  As a Mechanical Engineer, my intuition tells me that if road surfaces are exposed to more temperature extremes (not just temperature but also wet seasons / dry seasons), then roads should be in worse condition.  I'm guessing the mechanisms involve expansion and contraction cycles, viscosity changes in the asphalt, and erosion from rain - but I don't know for sure.   So why is it that the roads suck more here?  Are we using the same compounds but are unable to maintain it enough?  Or are we using cheaper compound? 

I read in the local newspaper many years ago about this.

The article stated that there are something like 12 grades of asphalt.

We use the 3rd lowest one.

The article went on to state that the "glue like stuff" used to hold the asphalt together was the difference.

Apparently, the higher the grade, the higher the cost.

The person that wrote the article then stated that they believed that Hawaii could choose to use the highest grade of asphalt, with the 30 year guarantee but the reason they don't is because it would mean the money that gets earmarked every year for road repairs would get allocated elsewhere.

I don't know how true any of the article was, I just remember it was front page news that day.

I remember that article too.  Weird stuff, like the fact that the slow-setting asphalt perferred by Hawaii for patchwork is actually water soluble, effectively guaranteeing that potholes, once filled, will have to be filled again after the next heavy rain!  Why does Hawaii prefer it?  It doesn't set up in the back of the trucks if not used quickly.

Also, a former Japanese classmate of mine had a friend who works on road construction in Japan come over for vacation and he said our construction technique is terrible. Not saying its the reason as IDK anything about road construction but it probably contributes to the problem.

I remember watching the news and they were talking about how we purchased a special pot hole machine but it's not even used because the type of asphalt needed to run the machine or something like that so it wad a huge waste of money.

Our tax dollars at work.

Back in the day...
I was on a "manhole raising" crew.
When the road got paved we would go out and raise the manholes. We had this asphalt in a bag which someone wait was like $40 a bag and we needed a little over a bag for each one. It was a cold mix "semi-permanent" Asphalt.

Well...I forgot what my point was...

This question is for anyone who knows about how our roads get paved (GZire?).  I've been to places like Tokyo, Connecticut, and just came back from a vacation that saw us in Vancouver, B.C. and Seattle where temperatures and weather conditions vary much more than they do here but yet it seems like the roads that I encountered had few if any potholes or bad cracks.  As a Mechanical Engineer, my intuition tells me that if road surfaces are exposed to more temperature extremes (not just temperature but also wet seasons / dry seasons), then roads should be in worse condition.  I'm guessing the mechanisms involve expansion and contraction cycles, viscosity changes in the asphalt, and erosion from rain - but I don't know for sure.   So why is it that the roads suck more here?  Are we using the same compounds but are unable to maintain it enough?  Or are we using cheaper compound?

I think you need to look at how the road was constructed, how it was designed, and how it is loaded in order to see what is going on.

A well constructed AC (asphaltic concrete) paving with a poor design and one that is overloaded may fail.  A poorly constructed road with a poor design, but very low loading may mean that the road remains in service for a long time...........you guys understand what I'm getting at.

Anyhow...........means of failure.  One of the common failure means in Hawaii has to due with loading and unloading the roads.  In general a "pumping" type action occurs which leads to the decay/destruction of the roadway.  Sometimes everything is built well, designed well, and loaded OK, but you can get water intrusion due to subsurface streams, etc.  Another thing that can mess up the roadway is diesel spills..........diesel will kill the binder.

So.............sorry, but you kind of have to take each failure on its own to see if it's poor design, construction, overloading, or other that is leading to the road failure.

I remember that article too.  Weird stuff, like the fact that the slow-setting asphalt perferred by Hawaii for patchwork is actually water soluble, effectively guaranteeing that potholes, once filled, will have to be filled again after the next heavy rain!  Why does Hawaii prefer it?  It doesn't set up in the back of the trucks if not used quickly.

We use cold patch to "patch" potholes.  This is opposed to the hot mix asphalt that is used for new paving.  Cold patch is meant to be a stop gap measure and is usually way under-compacted to stand up to the traffic abuse.  One other item to consider is that the patch is doo-doo.  It failed for a reason, so unless the subase is taken care of, the patch life will be less than if the base was suitable repaired. 

I referred to a "pumping" action above.  In essence what I mean by this is water gets into/underneath the patch.  You load it with cars and increase the pressure.  The tires leave the patch and the pressure decreases.  This action works to break apart the cold patch.

The patch area is also usually not prepared well enough at the edges and the feathering is not typically something that stands up well to abuse.

Again as above..........these are generalities.  You really need to look at each patch failure to see what's happening.

Hey G,

Perfect explanation!!! +1 

My first thought was that the constant higher temperatures, both from almost steady (75°?) air temperature and the sun beating down at a more direct angle (due to the lower latitude), kept the roads warmer and hence gooier* and squooshier* during a greater part of the year.

And therefore, more susceptible to damage, as opposed to the other places mentioned, where it gets colder and therefore the asphalt is harder during much of the year. 

Thus better able to stand flexing and other wear and tear over the six months that it's colder out.

That was my first thought.

Terry, 230RN

* These are highly technical terms usually used only by professional highway and traffic engineers. They are related in complex ways to the temperature-viscosity functions for the particular asphaltum grades involved.

Thank you all for your input.  I didn't see the article mentioned since I quit subscribing to the newspaper many years ago.  It sounds like that would have provided at least some background information. 

Thank you GZire for filling in the details.   It would seem that as far as the common failure mode you mentioned for Hawaii, this should be worse in places that are constantly wet and have roads that see much more traffic like downtown Seattle.   I'll have to stay longer some day and pay more attention to the various roads I travel. 

If it all comes down once again due to lack of money and/or poor prioritization on the local government's part - well, if it's going to cost so much to live we may as well get more for our money - and that means elsewhere.