Driveway Crack with Void

[69_sportsroof]

Hi all, I had a landscaper come out to give me a quote on some small stuff, and he ended up pointing out a problem that's been forming...

There is a ~1/8" crack in my driveway all the way across. He pointed out from the side that you could see the dirt had been eroded, and then he dug a small hole to the side and was able to put an entire shovel handle under the driveway under the crack. My guess is that the heavy rains we get here in Florida worked their way down through the crack and are washing the dirt away.

My main question is what is the best way to replace this dirt that's missing under the driveway. Second question is what product would you recommend for filling the crack to stop this from reoccurring?

 

[risc]

This is going to sound stupid but the pink hard foam insulation. When you do the math the PSI isn't very high, the foam is incompressible and waterproof.

 

[Dr Stan]

My main question is what is the best way to replace this dirt that's missing under the driveway. Second question is what product would you recommend for filling the crack to stop this from reoccurring?

The only way to repair this problem is to install a new driveway. If you attempt to stuff anything under the existing one, including dirt, you'll still have voids underneath and it will subside/crack above the voids.

On edit: One could use radar to find the voids, drill holes through the driveway and pump in a filler material such as concrete or expanding foam. However I would expect this method to be the most expensive.

I'm somewhat familiar with FL soil as I lived there. Essentially you have nothing but sand under the DW. It shifts around plus as the aquifer drops the ground above will give way. This is why FL has so many foundation repair companies.

Dig it out, then dig out 12 to 18 inches of soil below the bottom of the new DW. Fill with dense grade or shell and compact it as hard as you can get. Then pour the DW using screen or rebar and have fiberglass added to the mix.

 

[Bondo]

Ayuh,.... Call a contractor with a mud pump,....

Flowable fill can be pumped into the void, or concrete,....

 

[zeeway]

I had the same problem about 15 years ago. I dug out the side a little for better access. Then I shoveled/poked in about five bags of dry concrete mix (as much as it could hold). I did not add any water...I just counted on the ground moisture to harden the mix. So about two years ago, I had a two foot section of that driveway removed to do pavers, and the contractor encountered a very thick chunk of concrete from my repair job. He also found a sprinkler head, still active but clogged from the concrete, under the slab that had caused the original problem.