Practical Engineering
4 HN recommenders · recommended in 5 months, 2021–2024
9:34 · 2.7M views · Oct 29, 2018
Practical Engineering compares modern concrete with that of the Roman Empire, covering modern techniques like roller compacted concrete and water-reducing admixtures. It explains the tradeoffs of Roman construction versus reinforced concrete.
HN recommends it as a clear, balanced answer to claims that Roman concrete was better than ours.
6 comments from Hacker News
Here's a good video on the use and tradeoffs of Roman concrete engineering: this video TL;DW: whereas modern construction uses rebar as a way to keep concrete from fracturing under tensile stress, the Romans made their constructions enormous so that the weight of the structure itself would compress the material and keep it from failing from tensile stress. Their monuments weren't built huge just because it cool, but also because it was practical. But large concrete constructions are both expensive and take years and years to cure, and depending on your concrete chemistry the strongest mixtures can also be much more difficult to work with.
> Same goes for roman concrete. We know far more about concrete than the Romans did. We just don't bother to engineer everything to last forever, because that costs money and has little point to it a lot of the time. Yes, some buildings are works of art, but many things just have a function to fulfill, which is often temporary. Nobody is sad that the millions of mass-made soviet residential crappy buildings aren't still as good as new. If they were made to a better standard they'd still be ugly cookie cutter things. Practical Engineering has a good video on Roman concrete this video
The civil engineering-oriented channel Practical Engineering has a pretty good video on Roman concrete vs. modern. this video The primary tldw; is the fact modern concrete uses steel rebar for tensile strength, whereas the Romans relied on architectural techniques to minimize tensile forces on their structures. Steel rebar is the primary route through which concrete deteriorates.
Concrete without rebar lacks tensile strength, and Roman concrete is no different. When using materials with insufficient tensile strength, you're severely restricted in the kinds of structures you can build. That's why Roman buildings used so many domes and arches, and why they were massive . Practical Engineering has a good video about it: this video
I agree with your general point that we are in no way inherently superior to our ancestors, but Roman concrete, Damacus steel, and Greek fire are inferior to what we have today to accomplish the same things. Practical Engineering on Roman concrete. The TL;DR is that we are far more advanced. this video We do know how to make Damascus steel: [LINK] This fellow says we don't know how to make the historical Greek fire but acknowledges we can make identical substances: [LINK] We could build the Great Pyramid today using modern methods in 5 years using 2000 workers and $5 billion USD vs historical 20 years and 10s of thousands of workers: [LINK]