I have a concrete garage floor that is cracking near the apron entry at the overhead door. I'd like to understand how to repair this problem and if it's a project I can handle as a DIY-savvy person with zero concrete experience.
The garage floor is actually poured on top of a precast slab underneath (plastic sheeting between) which is the ceiling of a room below. That sub-slab ends right where the full-length crack is shown which explains why it had cracked there. This floor is a gravel/fiber concrete mix at a thickness of approximately 1.5 inches (at the cracking, anyway). The width of the crack is generally 1/2-inch with a few wider areas. The depth of the crack varies from 1.5 to 4+ inches because the substrate is eroding.
There are also 3 larger chunks of concrete (shown in the center of the picture) that have cracked all the way around and thus are lose...and I imagine should be removed and replaced with new material.
How should this be repaired and with what materials?
I've received a few suggestions from the home store but I couldn't tell if they really knew their stuff or just wanted me to buy stuff:
- Use quick-setting cement plus bonding adhesive to repair the large voids from the broken/missing concrete.
- Fill the crack to a reasonable depth with sand/backer rod and then apply a self-leveling caulking or concrete crack filler.
- Or, use non-shrink precision grout in the crack.