How do I reinforce where I cut concrete out?

[ITSANSS]

Hey, ya'll. I had some major cracks in my slab in my garage that I cut out yesterday. I'm getting new garage doors and I had to remove a section directly underneath one of the doors to make the work possible. The old door was buckled from the concrete being so uneven. While I had the equipment rented, I also cut out some cracks that was letting water flow directly into my garage when it rained.

Question being....now that I have these spots cut out, what do I need to do to reinforce the new concrete? These spots are hardly wide enough to even get a drill in there to tap into the sides of the existing concrete. Just wondering what my best option will be here. The heaviest thing that will ever be driven on this concrete is a 1/2 ton pickup truck.

Thanks!


http://i1210.photobucket.com/albums/cc415/bbar1988/IMG_4351_1.jpg

http://i1210.photobucket.com/albums/cc415/bbar1988/IMG_4350.jpg

http://i1210.photobucket.com/albums/cc415/bbar1988/IMG_4346_1.jpg

http://i1210.photobucket.com/albums/cc415/bbar1988/IMG_4348_1.jpg

http://i1210.photobucket.com/albums/cc415/bbar1988/IMG_4347_1.jpg

 

[LXCam]

I would have suggested to make those area wide enough to dowel them with rebar. But at this point I'd roughen the edge, clean it big time and use a latex cement glue on the edge as well as in your patch mix and fill them

And sorry, I didn't open the pictures so maybe someone else will have a better idear.

 

[Bondo]

Ayuh,... That appears to be an extremely thin slab,.....

 

[ddawg16]

I agree with the above.....those holes should have been larger so you could drill holes for dowels...I see you have issues with the ramp at the front of the garage....those sections are going to shift relative to each other...

 

[ITSANSS]

Damn. Guess I should have asked these questions BEFORE I did the work. In the case of putting in dowels, I'd have to re-rent the equipment at ~$120 plus getting more help, plus finding a day to do it, plus delaying my garage doors install, plus aggravating the neighbors with all the noise. SOB!!

 

[ddawg16]

Use a hammer drill with a long bit....drill at an angle......then make dowels long enough to overlap with one on the other side....bend them down so they are below the surface by at least 1.5"....wire them together....pour your concrete.

 

[ddawg16]

Forgot to add....#4 rebar will work just fine.....and you can bend it....

 

[ITSANSS]

ddawg,

I will definitely give that a try! What size drill bit fits the #4 rebar? What spacing should I use between bars? How much penetration into the existing concrete should I try to obtain?

The existing concrete is approximately 4" thick. Thicker than that in spots and a little thinner in others, but average 4".

Thanks so much, ya'll

 

[DC73]

In addition to the rebar suggestions, use a concrete bonding adhesive on the existing concrete.

http://www.homedepot.com/p/SikaLate...hesive-and-Acrylic-Fortifier-187782/202521398

I would also consider using the fiber reinforced concrete. It's only a couple dollars per bag more than the regular mix and is good insurance.

http://www.homedepot.com/p/Quikrete-80-lb-Crack-Resistant-Concrete-100680/100318448

DC

 

[rsanter]

Those areas are not big enough. The bigger the chunk the more stable it will be. 12" wide is about the minimum and 18"-24" is better.
And you need to both pin them to the slam next to it as well as you may want to undercut under the slab next to it by just a little.

Bob

 

[doctordirt]

Answering your question, #4 rebar is 1/2"