I have a slate patio that was installed the year the house was built (1940) very charming. The slate is ~ 1 inch thick and is inbedded in a cement slap that is 12 inched thich or more. Some of the slate is curmbling. What can I do to fix this? The slate is rough cut and the gap from one piece of slate to the next is 1-2 inces apart, so I can't just removed the cumbling pieces and install a new piece. This is leaving deep pockeds for water and ice to form, a tripping hazard and is starting to look bad. Please help. Is there some kind of material that can be colorized and poored into these areas? HELP

You could remove the slate and pour in colored concrete mix. QuickCrete makes coloring dyes for concrete. Color it to look like slate. Use a sand or mortar mix instead of a concrete mix.