why do the groove the payment before they re pave?

Answer 1

So the new asphalt will adhere better. A grooved surface is better than a smooth surface for that. Sort l=of the same reason you sand the old paint on something before you apply new paint over it.

Answer 2

re-grooving the pavement creates a mechanical bonding surface for the new layer of asphalt that is being applied. Without it, the new layer would crack to reveal the old layer....which will lead to huge potholes and eventual surface failure....and lots of broken suspensions.

Answer 3

it is like scoring in pottery and other stuff.
two high frictions surfaces will more likely stick together the way you want them too rather than form some other way.

with pavement, it allows the new layer to smooth over by evenly spreading across the recesses rather than clumping and causing a wavy pattern in the sidewalk. although that would be cool.

Answer 4

The asphalt needs something to adhere to thus, a coarse surface. Otherwise, it would just lift up. And also, it removes the old surface to keep the road at a certain height or thickness.

Answer 5

for the same reason they groove the tile adhesive when you lay tile. It holds better.

Answer 6

So that the new pavement will stick to the old stuff.

Answer 7

so it will stick...like sanding before you paint...