When to Repair Versus Replace Concrete Slab?

Question

I am a first-time homebuyer and purchased an older home in the Northeastern US. While I've found great infomation here on my many DIY projects, I have not been able to determine whether or not my garage floor is in a "refinishable" state.

The Problem: I have zero experience with concrete, and had originally intended on doing the refinishing process myself. After scouring the internet for how-to videos, I kept noticing that most of the slabs being repaired are in much better shape than what I'm dealing with.

The garage is a concrete slab poured around cinderblocks; I've included a photo of one large problem area, which has very long, deep cracks, and pitting all over the place. The cracks are rather wide as well. The paint removal process is also taking it's toll on the slab, bringing up chunks in the weaker areas.

My Original Plan:

1. Strip the original paint/epoxy using stripper and floor scraper.
2. Clean and V-Score cracks, and remove existing patchwork.
3. Apply concrete patcher & bonding agent to cracks and problem areas.
4. Sand smooth and spread resurfacer across the entire slab.

I grew concerned over the amount of concrete patch I would need to purchase to achieve results - more than what would be considered simple patchwork.

My Questions:

1. Is this concrete slab repairable, or is it beyond it's usable life? If you could please explain how you came to that answer, I would greatly appreciate any context (i.e. When should you consider full replacement for any slab?).

Answer 1

It's done-for. Whenever you have both severe surface degradation and spider cracks there's no turning back time. No patch will hold up with so many independently-movable segments. You'd have to pour a new slab that's robust enough to span such movement.

If it didn't cause problems at the door opening you could lay paver bricks over the top. They'd do pretty well I think. That would mean doing the same out into the driveway, though.