Can you get to the side of the slab and sort of dig a bit of an inspection hole? That would tell you if your slab was poured over a proper base of packed crush or not. Far too many driveways are poured over soil and you will not avoid cracks then. No matter the wire, rebar or additives. If there is no road base under your slab then I'd simply sell and let your buyers deal with it as they may. If there is road base you might price out removal and pouring of a new slab and see if it fits...I doubt it increases your sell price by enough tho. I do know that a slurry of cement and water, rolled onto a stained concrete walkway gives it a nice, uniform fresh concrete look...for a while.

LetÂs get this straight so the others reading this thread are not as confused as some seem to be; as I understand your post the $1,500 is for the demolition, removal, replacement and finishing of an entire section of the garage floor. My guess would be, (you didnÂt say) thatÂs probably a minimum of around 1.25 to 1.85 cubic yards depending on a thickness of 4 or 6" if we assumed a 10Âx10Â area, of which the area depicted, is only a small portion. And while I think that $1,500 is a bit pricey, I would doubt that anyone would do it for less then $1,000 when you consider manpower, equipment, haulage and disposal of the spoils, and time required for finishing. Two things would be helpful, a photo of the entire section of the slab and a note as to what region of the country you are located in. It is plain to see from the photo that this is not a simple crack in the concrete, or if it was it is no longer, the concrete has been undermined, there are hydraulic forces at work there. From your photo, or probably any photo for that matter it is impossible to tell to what degree the substrate of the bulk of the slab has been impacted. But letÂs assume the rest of the slab and its substrate is good, I would still not call this a smear on some patch and walk away job. I would saw cut back to uncorrupted concrete, remove the junk, and take what ever steps were necessary to firm up the effected substrate (dig it out and bring it back up with crushed stone). I would then bore and epoxy a couple dowels into the existing good concrete, apply a bonding agent to its cross-section and then pour a fresh 4000 or 5000psi mix. I know that may sound daunting, but it is not as bad as all that, for me it would be maybe a 2-hour job, the fact that I have the tools is a help. But even for anyone with rented tools I couldnÂt see you spending more then half a day at it. Of course none of this is of any use (in time) if you donÂt correct the issue that caused this problem to begin with. And by the way, a word of caution, if you do decide to smear on some patch walk away and say "you canÂt see it from my new house", then I would be sure and disclose this to the purchaser. Because if the substrate of that entire section of slab is eroded and a month later it collapses in I know my attorney would be questioning your prior knowledge. I know just enough about concrete to be dangerous, here is one of the more recent projects I worked on. http://i90.photobucket.com/albums/k269/punk_itup/5dbc0126.jpg

the garage is likely due to poor/no prep before pouring the slab. once the ground settled, the slab lost support and split. you can try concrete patch to fill the gaps, then paint or mats to cover it. i would also recommend getting a mudjacking company to come by and give you an estimate on fixing the ground under the slab. as to the drive, many companies no longer haul concrete to the landfill anymore. they actually grind it up and reuse it to make new concrete. i have seen 2 new Walgreens go up in the last year and in both cases they ground up the old parking lots and mixed that up to make new concrete for the new lot. check to see if anyone does this in your area. if not, the other option is to check and see if anyone wants the chunks for erosion control. many people here line the ditchbanks with old concrete chunks to keep them from washing out.

Some places sell 30% strength "horticultural" vinegar. I have had fairly good luck killing certain weeds in San Antonio (not Canada). There are problems with that stuff. First is it is extremely dangerous to handle. If you get any in your eyes, you are blind for months until your cornea can heal. Second, it does not always kill what you want. Third, it does seem to kill what you want to keep, so overspray is a problem with it. Fourth, you don't want to spray acid near concrete, as was mentioned. On the good side, plants that are going to die are dead and crispy in 20 minutes. Also it smells like my grandmother's salad dressing for an hour - but also don't breathe the stuff into your lungs when you spray it. But I don't think the grass in the cracks is THE problem. Giant slabs of concrete are not going to move with a few weeds. If it was brick sized paver stones, then maybe, but not slabs. What does move slabs of concrete is upheaval from frozen soil underneath. Could that be the problem? Non-engineered slabs poured over shifty clay can also break concrete over time. Also, tree roots can move or break concrete over time. Do any of these alternate ideas seem plausible?