Concrete bonding

ranger11 · Apr 30, 2016

Does any know the proper way to bond concrete? And will it hold up or will the thin concrete start cracking over time?

I want to pour another slab in front of my shop and I want to tie the new slab to the ramp that goes into my shop. Here's a rough drawing of what I want to do

hokie_yj · Apr 30, 2016

I'm certainly no pro at concrete work, but we did something like that on a few different projects where I worked a few years back. It was usually adding on to an existing slab, not a ramp, but we drilled holes into the side of the existing slab and used a two-part epoxy to hold rebar into those holes then tied the rebar in the new slab to those. I don't remember exactly how far apart we spaced them but I want to say it was every 18"-24" or so.

InittowiniT · Apr 30, 2016

Demo saw cut ramp to 4 in thickness and then drill and epoxy rbear. Any concrete thinner than two inches will crack. There are some surface fillers that won't crack but to expensive for a driveway.

stano · Apr 30, 2016

The rebar/epoxy is what I do when I have to tie slabs together. Being as its a driveway with traffic, I'd cut the existing slab right were you want to join them, even if it's just a notch that is at least 2-3" deep. That feather edge will crack out and piss you off in a short time frame.

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halcat · Apr 30, 2016

They require us to square cut the existing slab and drill holes in it but install smooth greased rods for expansion/contraction, it won't move but about a 1/4 in. If it bothers you calk it. Make sure your rods and hole fit snug. If you epoxy them make sure you go in one and a half ties the thickness or they could pop the concrete.

ibrokeit · Apr 30, 2016

Cut the concrete back with demo saw to where it's 4" thick then dowel 12"-16" pieces of rebar into it every 18" or so.

ranger11 · Apr 30, 2016

Re:

Thanks for the info.

poolman · Apr 30, 2016

ibrokeit said:
Cut the concrete back with demo saw to where it's 4" thick then dowel 12"-16" pieces of rebar into it every 18" or so.

This, I do it all the time

ranger11 · Apr 30, 2016

Re:

So I think have a problem the ramp is only 4" thick on the edges I'm assuming its 4" in the middle. I don't think I can do the dowel method. I'm thinking the whole ramp may have to come up.

mdo817 · Apr 30, 2016

Chop the ramp, dig in front of it for at least 4" to butt up to it, let the area act as an expansion joint, you will just have to poison the weeds a few times a year.

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