Was on the NJ parkway and was wondering, why it’s not smooth. The roads pavement kept alternating between a smooth asphalt to a rougher substance, probably concrete. Maybe I’m using the wrong term but I’m curious.
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Asphalt is commonly used to patch over damaged sections of concrete roads. Up north this happens more often because the freeze/thaw cycle is really hard on them. I suspect that’s what you’re seeing
All I know is that old material that was a light tan color with the grooves in it was super sturdy and that stuff would last decades. I’m pretty sure it was much more expensive and now they’re using this cheaper asphalt that’s much more prone to giant potholes. “They don’t make ‘em like they used to”.
Edit: Yep, did some research and looks like it’s called rigid pavement. Says the maintenance costs are much lower and it’s much more durable but it’s super expensive to initially install.
I think this is your answer. Cheapskate government trying to save a few bucks so in a lot of areas you’ll see regular asphalt pavement when they have to re-do sections of highways and interstates and the old rigid pavement in the areas that haven’t been redone yet.
It depends on the nature of the roadway (highway or interstate for instance), but generally speaking they’re a cooperative effort between different levels of government and as such different municipalities/counties/states will use different contracts among different entities who themselves may use different materials. And in a lot of cases, the materials may be more suited to their environment (or just cheaper).
High pressure concrete is used on areas where a lot of weight is exerted and asphalt warps in the heat under pressure creating ruts in the road. It is also common at red lights and bus stops on highly traveled surface streets.
Different sections are built or resurfaced at different times, according to the specifications at the time of the project.
Concrete and asphalt are both used for different types of roads.
Asphalt is the most common and is that dark color. It is cheap and 100% recyclable. (You can literally just heat it up and re-pour it.) It is however not too durable.
Concrete is very expensive and it takes days to cure, but it is strong. You usually use it in cities or interstates with high traffic. Those are the light gray roads.
I imagine what you’re describing is concrete road, but it is damaged. They probably filled in the gaps with asphalt instead of concrete. This is because asphalt is way cheaper and can be poured and dry in less than a day. Concrete has to chemically cure and the road would be closed for days.
concrete roadways are very expensive and their somewhat longer time between servicing almost never justifies itself. there’s almost always a tangible reason. probably because there’s something under the road. asphalt doesn’t support itself. the asphalt is a couple inches thick, but the worked earth goes several feet down.
in areas where you can’t do that, concrete is a popular option. water is a common enough problem. if the local utilities can’t go full depth, you can get bands of concrete roadway where they cross.
I’m in Florida, the freeways roads here change material (into concrete) when it’s elevated, so going over a road or water.
[Example](https://goo.gl/maps/AYow8BnPbT1t9fN16)
You giving an example would also be helpful.
They also use different materials for controlling the heating/cooling effect. Concrete (and asphalt) react to the weather. When it gets cold it shrinks, when it gets hot it expands. All road construction takes this into account. If you allow the road to all shrink and grow as one unit you get all kinds of crushing, flaking, splitting problems. Ever seen asphalt with crevices in it? That’s what happened.
The larger the mass the more these forces act on it and the stronger they are. So you isolate. That 3 mile stretch of asphalt at the bottom of the hill is going to turn into black soup after a hot summer and then rip apart when it gets really cold this winter. If we cut half mile chunks out of it, replace those with concrete or a bridge even here and there, we can make sure that the overall forces acting on the road mass are confined to sections of it, those forces will be less strong as there’s less of it. And next time a chunk of asphalt or concrete goes bad we can just patch it, instead of having to cut the entire section out.
Concrete/cement will crack and ‘gravel’. Because it is too hard and brittle.
Asphalt will crack and buckle. Because it is too soft and gel-like.
By using the right material in the right situation or even the right combination of them, you reduce road maintenance, wear and tear on cars and tires and can influence traffic speed, visibility conditions, and so much more.
Grooved pavement is another solution to similar problems. It is designed to shed heat, flex with heating/cooling cycles, reduce breaking and cracking and to make people do the right speed. But it beats up tires and car frames a little bit extra so you only want to use it when there aren’t better, more economic options. You’ll often see it on roads leading into mountains or other places just on the edge of ‘civilization’ because it has to be maintained a lot less than ‘normal’. Places where it is difficult, annoying or most importantly expensive to get a road repair crew.
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