My concrete driveway is about 16 years old and has undergone some settling. At the street, the last slabs are a couple of inches below the level of the concrete curb; the rest of the slabs are not so bad, but still in need of leveling. None of the slabs is cracked (except at the deliberate score lines at the edge of each slab).
Last night a contractor came out to bid on the job. I’m familiar with the basic concept: bore a hole in the slab, pump something through that hole to raise up the slab to the desired height, then seal the hole. I had thought it was some kind of cement/concrete mix, but this guy told me that most contractors use a sand/lime slurry that tends not to spread well, and also tends to wash away over time; according to him, those contractors typically offer a 1-year warranty on their work.
Instead of sand/lime, this guy claims they pump some kind of pea-gravel mix under the slab. He says it spreads better to provide more even support under the slab (prevents cracking), and doesn’t wash away over time like the sand/lime slurry. They offer a 5-year warranty, provided the gaps between the slabs are properly sealed (they recommend a sealant, but don’t require me to buy it from them or have them install it).
A second contractor showed up this morning. He uses a lime slurry, because he claims that pea-gravel mix doesn’t spread/distribute as well as the lime slurry. Further contrary to the first guy’s claim, this second contractor offers a four-year warranty on his lime slurry job.
I am waiting until I get bids from a couple of other potential contractors. Meanwhile, can anyone here fill me in on anything I ought to know about this process? Good/bad experiences? Is there a real difference in durability or slab support between the lime fill and the pea-gravel fill?