Yes it can be substituted with lime mortar.
Slaked lime mortars have been used for thousands of years whereas the use of cement in construction is relatively recent. The vast majority of buildings in this country dating pre 1910 would have been made using lime mortar to lay the bricks, render the outside and plaster for the inside, either directly to the walls or on to wooden laths. There are many examples of these traditional methods going back hundreds of years that are perfectly sound.
Have you ever seen Charminar? This beautiful structure is constructed with lime mortar in 1591, it is still functioning (even today 1000’s of people climb it & its still standing without any damage).
I don’t know how many of you know about charminar but i guess most of know The Colosseum. The formula for this Roman structure also starts with limestone builders burned it to produce quicklime and then added water to create a paste.