concrete repair???

[Fred Voorhees]

Hey gentlemen....the below picture is of the apron in front of my two car garage. It has developed a rather large crack/void and I want to repair it before the damaging winter freeze and thaw. As we all know, simply cleaning out the void and pouring in some new concrete will not do the trick. I have been reading up and it appears that a bonding agent applied to the existing walls of the area, plus the use of special bonding cement or concrete, even with the addition of bonding agent to the patching material will help in creating a long lasting patch job. I also intend to try to use some rebar in the repair. I don't beleive that I can drill straight down into the area below the crack. It may extend down to the bottom of the actual apron. If I can I will, but at the very least, I will be drilling some holes diagonally into the fractured side of the control joint and then inserting some appropriate rebar for the patch to latch onto. I will be prepping the rebar also to resist corrosion. I will be cleaning out all of the loose rubble and getting back to solid concrete pad.

What does everyone think of this method? Anything else to add as far as recommendations? Appreciate it fellas.

[Stephen Tashiro]

What is the width between the two cracks? I'm assuming that you will remove all the concrete between the cracks. Guessing from the photo, rebar looks like overkill to me. Did the place crack because the ground washed out from under it? If so, you should investigate the cause of that. I suppose if you conclude that you can't support the new concrete with soil and gravel, then rebar might be used to make the patch a bridge.

[Russ Filtz]

Not a concrete layer, but I would also not try and feather the new pour into the current cracking. Along the edge of the crack (to the right in your picture), I would try and chip it down so you have at least a bit of a lip there.

Also, follow the bonding agents instructions exactly. The best are epoxy based. You may have to soak the existing concrete with water for a day or so before. You also don't want too much or too little bonding agent. Look for non-shrink on the grout/mortar you use to repair. Note - You WILL NOT be able to match the existing concrete no matter how hard you try, hence the patch will be noticeable.

You may want to do this to get a clean edge (saw with concrete blade)

B. Spalled Joints:
1. Saw edge 1 inch deep and 6 inches back from the old joint.
2. Remove unsound concrete between saw cut and the joint.
3. Place wood or fiber spacer to thickness of joint at joint line.