I removed a 5'x5'x4" slab of sidewalk, in one piece (still sore), to repair a water line. I now want to return the slab as it was. The slab was originally poured over 4 inches of pea gravel. The bottom of the slab is of course very uneven and pitted and uneven thickness: 3" to 5" thick in spots. I am not sure what to put down over the pea gravel to receive the old slab so as to get a good level fit. I have leveled the pea gravel down about 1.5 inches below where it was and planned to pour 1.5 inches of concrete then drop the slab back in place. I am concerned about:
1) Gravel or viscosity in the new concrete preventing the slab from settling down to grade.
- Should I use some type of grout instead of concrete.
2) Not being able to apply enough pressure to get the slab down into the fresh concrete to grade.
- Is there some type of vibrating device either beneath the slab or on it that will work the slab down to grade?
What ever advice you can offer I'd appreciate.