Air spade excavating sidewalk/driveway base.

[Cynfawr]

Hey guys, I wanted to see if anyone had experience using an air spade to excavate to root pruning in structural/machine compacted soils?

I've been involved with some sidewalk repairs and the root pruning aspect seems to be a bit of an afterthought.

I would like to see a greater importance put on it and a higher quality of work.

The excavation of the compacted gravel/fill material under the sidewalk is probably the main struggle facing the guys trying to make good cuts on these roots.

Would an air spade be effective for this purpose? Hydrovac is too expensive and hand excavation is very labour intensive.

Would wetting the base material be helpful?

 

[oldfortyfive]

Air and water are similar in cost. Real issue is the vacuum system to get the debris out. Without a vacuum system you have a mess. One of these would be awesome: https://www.truvac.com/equipment/trxx

 

[oldfortyfive]

Found this on air vs water

 

[ATH]

It will go through the aggregate just fine. Compacted dry clay...not so much. You get some moisture in there, and you can start breaking it up with air excavation.

You don't need to move a lot of soil very far to get to a few roots most of the time.

The city doesn't already have a hydrovac truck available?

 

[Cynfawr]

Thanks for the replies, and for the document oldfortyfive! It was nice to see those pro/con lists.

The trailer mounted unit was pretty cool too!

Unfortunately there's no budget for a hydrovac truck for this work. I don't believe the city owns one, always hired in.

I'm trying to keep the cost relatively low, so wasn't thinking about the vacuum side of things. I was hoping to just put up some barriers like for stump grinding, blow away the dirt/gravel, cut roots, and backfill.

I'm aware it will be dirty work to do it this way. I just wanted to get an idea of whether the airspade would be efficient for displacing that sort of material.