we know a lot more about roman concrete now that they have studied the materials from aqueducts and the pantheon. has anything we've learned made it to the field?Well it hasn't been all that long ago (historically speaking) since they rediscovered concrete in 1756.....With Portland Cement coming along in 1824......It had been lost since around 480 with the split of the Roman Empire.
The Invention of Concrete: A Complete History
Concrete has a long history. Since its discovery over many thousands of years, concrete has evolved, adapted to change, been lost to dark ages, and rediscovered again. Concrete has proven itself to be…concretequestions.com
and, i do not believe that the gothic masons deliberately mixed human blood in their mortar. accidents happen on any large project, the cathedrals were the largest scale urban construction project ever in a feudal age of castles.