Here is a paper discussing masons taking an oath to commit human sacrifice in construction, usually a woman with child, for which they will receive money:

Almost forgot to mention, it's a "legend"

....ballad...."Mason Clement’s Wife" or the "The Walled-In Wife," ....the wife to be sacrificed will not be walled-in alive, but first burnt, while afterwards her ashes will be mixed with the mortar, and used for the sustainability and durability of the walls.

Because we made an oath, an oath that we’ll build up

The first wife who will arrive

We shall catch her and we shall throw her into the fire

And we shall mix her ashes into the mortar

And only this way will the walls stand

And we shall receive our reward of gold and silver

Consequently, the burning of the wife’s body at the construction site emphasizes even more the identification of the cornerstone with the altar.

One common feature....is the person sacrificed i.e. the woman, in most of them the woman being with child.

Source: http://archive.is/vsRtW

The Romans mixed ashes, as well as blood, and (horse)hair into their concrete:

https://www.shelbymaterials.com/blog/romans-concrete-reinforcing-fibers/