Tuesday, about 4 pm, I painted the concrete walkway that leads up to a rental that I am about to rent. I didn't water wash/scrub the floor because of the time of the day and I was running out of it. Big mistake. I painted with about 1/4 of a can of paint that was leftover from the same job 2 years prior. It looked perfect when I finished. The next morning and all day long, we had downpouring rain. Sure enough, by the afternoon, the paint was bubbling in places and is now fully peeling. What do I do now?
Try to scrape it all off and then roll on a bonding agent and then use paint that's specifically for concrete. If you are near a real paint store (not big box) they will have all the info and products you need