tflfb wrote:

I have to replaced the concrete expansion joint a couple of times in my
driveway where it meets the street.

Its made of a asphalt material, but it rots away over the years.

What is I remove the asphalt and instead of using that again, I use this
spray foam they use to insulate, it comes in a spray can dries in a few
mins.

Thanks Tom.

I've had good results using backer rod and then sealing with
[self-leveling] polyurethane caulk.

BTW, I believe the quality of the backer rod from building supply store
is better than that sold in big box stores.