Depending on where it is, you can patch with mortar. You can purchase a "just add water" mortar mix.
Hi Les. The very nature of concrete is that it cracks. If they're structural cracks, you need to find the cause. If they're just cosmetic, fill with silcone caulk and while the caulk is wet, sprinkle cement onto caulk. When it dries, the crack will virtually disappear. Good luck.
Hi Les! Take a look at these links I have listed & see if they are helpful to you! Good luck with your project. Merry Christmas.
Take a photo to the home improvement store and ask for their advice on materials and application. They have the newest materials and application tools to do a professional job.
You can conceal it behind a painting.