Similarly, I'm always impressed by how smooth the ashpalt highways in Toronto are, even though they are spiderwebbed with cracks absolutely everywhere. That's because the cracks are filled each spring with some sort of sealant. They make a regular slapping sound as the tires pass over them, but cannot be felt.
I don’t think you could do the repair with asphalt. I’m not even sure I’ve ever driven on a concrete road, as down here in New Zealand there aren’t any I don’t think.
The current repair practice is to pour tar on the asphalt road and then a coating of road gravel. It’s noisey, comes off when heavy vehicles use it, comes off with heavy usage or heavy breaking, comes off in hot sun and it’s utter trash. It’s cheap though!
you are describing an asphalt microseal over the entire road surface. they are describing sealing of cracks using asphalt "tar snakes". They address different problems.
Road resurfacing improves stopping distances and rough rides if the road is overall in ok condition. If the road has large cracks in it this does nothing
Tar snakes are used to seal cracks from water because after rain the movement of vehicles over the wet subgrade under the road creates a pumping effect that ejects subgrade material out from the cracks and causes potholes in the future.
Of course they don't add rebar to asphalt roads, that would be ridiculous. The sealant process is done manually, with some poor sod pushing a machine along each crack and injecting hot sealant which prevents further water incursion and the associated frost heave. That's partly why I'm so fascinated with it: some sections of highway are cracked everywhere, with hardly a square metre that doesn't have a crack running through it, and yet they're extremely smooth.
It's funny how other commenters on HN are telling you what it probably is, even though they might not live in Toronto.
To my knowledge, it isn't any special application of product. It's literally cheap asphalt they pour on top of cracks and potholes and pound it down lightly. The reason why it's surprisingly smooth is because a thousand plus cars have driven over it, flattening it down to road level.
> "Crews place asphalt and rake it into the pothole. Then they tamp down the asphalt and smooth it out until the road surface is improved. The job takes 15-20 minutes."
They do this because it is literally impossible to get to all of the potholes in spring. Want some neat stats?
We have the same thing on our neighborhood asphalt roads. It's a noisy day every few years when they do it. One truck idles up the road with a big air compressor and a guy walking along behind it with an air nozzle on a stick, blasting anything loose out of the crack. It's pretty loud, predictably. Then a little ways behind him comes another guy with a tank of tar filling the cracks. Every few years on an alternating schedule they put a liquid asphalt coating over the top of the whole thing.
It's not the most beautiful thing, but it's smooth.
I'm 97.92% sure they don't actually do this because it's better. It's cheaper than resurfacing -- then they drive along with a big machine that grinds off the top few inches of asphalt, crushes it up, adds tar, and puts it back down to be rolled.
