i've got a slate flagstone walkway that's missing some large pieces of slate. it looks like it was laid in a mortar bed and pointed with a half inch gap. i'm looking to repair the parts of the walkway that have missing pieces of slate. i've purchased enough slate and cut them to fit in the vacant areas. i've jackhammered out the mortar bed and am ready to set the new pieces of slate in the holes i've made. MY QUESTION IS: what type of mortar should i use to set the slate in? i want this job to last for a while and be strong enough for fairly heavy traffic. i have some type s mortar, will this do the trick? thanks for any suggestions.
-chris