Why was Roman Concrete Forgotten during the Middle Ages?
One of the mythical mysteries of history is why after the Fall of the Roman Empire was the useful technique of building with concrete forgotten? This video answers some of that.
Why is that important for Green Wizards, and in particular Green Wizards who write? With Greer's theory that we will be seeing a slow decrease in available technology and a new Dark Age in the next few centuries, ask yourself "What modern technology will the people of the future forget?" That answer can give you story ideas.
The short answer from the video is that the technique wasn't really lost but abandoned because the huge buildings that concrete was suited for stopped being built. The needs of the population and the tastes of the monied patrons who financed the construction changed. Huge stadiums that need electrical lighting and climate control will fall to the wayside in favor of older open-air stadiums which are used on good weather days only. The monsters of the current time, which are as much a product of ego and self-aggrandizement as they are of modern construction techniques will disappear for those kinds of buildings that use less.
One thing I found interesting, is the way that early Roman foundations were built, not with pouring concrete as we do now but as shallow layers. An exterior mold of bricks or cut stones was made and supported, then a layer of broken tile or stone was put in and the gaps filled with a slurry of mixed mortar. This was tamped down with wooden paddles. Once dried most of the way, another layer was put down. Given all the current concrete structures, I could see this kind of re-use becoming popular as a way to cut costs. As future Ruinmen, disassemble old buildings for their metals, the remaining concrete rubble will just sit there looking for use.
What do you think? What things will we forget?