[Right_Wing_Madman]

Why was Roman Concrete Forgotten during the Middle Ages?

Before the British Empire, the Roman Empire was the most advanced civilization in history, particularly in the fields of medicine and engineering. The Roman Empire was right on the edge of the industrial revolution, but didn't quite make it. In the middle of the second century the Romans invented prototypes of the first steam engine but did not figure out how to apply them in a factory, locomotive, or ship. Roman aversion to labor-saving devices is probably what held them back. After the breakup of the empire in the third century, it would take 1500 years for civilization to rediscover techniques and technology the Romans used.

[SunkenCiv]

[snip] Suetonius relates that an inventor approached the emperor with plans for a hoisting machine that would greatly reduce the need for manpower but was rebuffed with the reply, “I must feed my poor.” Vespasian feared the machine would exacerbate unemployment in a society already overrun by idlers and slaves. Labor saving devices such as the water wheel were not wanted and consequently were neglected until there was a significant decline in both the general population and the number of slaves late in the 4th century. But a society that does not use its inventors will eventually lose its inventors. [/snip]

Stanley David Gedzelman, The Soul of All Scenery: A History of the Sky in Art, link, see Chapter 3

http://www.sci.ccny.cuny.edu/~stan/skyart.html

https://arsendarnay.blogspot.com/2012/05/vespasian-jobs-over-machines.html

[OldWarBaby]

Brits? Romes? yeah they were pretty good but so were the pre-Egypts. We still don’t know how to build a pyramid. And numerous samples of pyramid stone show tiny sea shells. Could very well be aggregrate. And the early S. Americas knew how to mold stone either by casting or some hot process which we can’t do?

A huge factor in the demise of Roman style aggregate was the slow disappearance of slave labor to make the crushed rock. The industrial grade rock crusher hasn’t been around long. The necessary steel didn’t exist. I know of a 19th century monastery built so that the monks could pack rocks up about 3 stories then drop them to break them into aggregate. One can’t use just any old rock to make spec concrete——dense, no porosity, high compression strength, etc.