Use Top N Bond.
https://www.lowes.com/pd/Sakrete-Top-N-Bond-20-lbs-Vinyl-Concrete-Patch/3059093
Other places probably sell it too. I’ve used on several projects, including a worse looking garage apron. It has held up great for nearly 3 years so far.
I used this procedure:
1. Scrub the area clean. Power wash if you have one, hand scrub if not. Rinse well. Light wire brush area and clean out cracks and any loose pieces (I had several deep cracks and a couple small broken areas). Rinse again. Let dry overnight. Blow or brush out any remaining debris.
2. Mix small amount of Top N Bond. Start with about quarter cup of water in small container and add mix till just bit thinner than peanut butter. (As you get used to working with it you might want to use bigger batch, but remember it sets up quicker than you think.) Wet cracks with sponge or old paint brush so damp, not puddled. Fill cracks to top, popcycle sticks and fingers work best. If you have broken areas, use same method but only fill in about 1/2 inch deep at a time, allowing to dry between (see package directions). Let dry overnight before step 3. If you have no cracks or broken areas, skip this step.
3. Run masking/painters tape across length of the apron about middle of garage door, so if door were closed tape is not visible. Starting with about 1 cup of water, mix a thin batch of Top N Bond, so it’s about like a thick paint. Work with small batches. Again, get apron damp but no puddles. Using a stiff brush (I used one similar to this:
https://www.amazon.com/dp/B004HXNWV0/?tag=atomicindus08-20 ) brush a thin coat across apron. As it starts to set up you can use a damp sponge or chip brush to texture the surface. Note this can spatter if you’re not careful, so either cover up or move stuff like cars and be ready to rinse off your driveway. Remove the painters tape after you’re happy with the look, but before the coating is dry. Use damp sponge or brush to smooth the edge.
I’ll try to post some pictures later.
