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There is no mention of the mechanical performance of the concretes mentioned. That's key in what concrete is used, and some of the degradation issues. For instance, much concrete spalling is due to corrosion of the rebar. No rebar? Less spalling. But less strength too.
Furthermore, we have many other concrete mixtures besides Portland cement.
Ultra High Performance Concrete has existed for many years, and gives superb performance in many ways.
And there are even better performing concretes than UHPC, and others that release less CO2.
The driver is cost. And since the cost of Roman concrete wasn't mentioned, there's no assurance that it will replace anything.
I saw a documentary on this a few years back - apparently it has some properties that modern concrete/mortar mixes do not have in particular the hydraulic version.
However, Dr. Torch is dead on - modern concrete/mortar mixes are not limited to Portland Cement. One of my best friends makes concrete for a living and it's a whole art and science to itself for differing applications, applications with with different aggregates/mixes - fascinating subject - so to just blanket say that the Romans did it better isn't exactly true.
When reading about Roman construction projects (and the politics surrounding many of them) I always wondered about their concrete, which was so good that many of their structures still exist (as the article notes). So thank you for this article, despite whatever inadequacies it may have. I found it very interesting.
Readers may enjoy the original release on which the BW article was based, as it covers more extensively the composition and cost issues. The materials for this recipe are far more common around the world than Portland cement, readily available, as well as less demanding to produce. It all seems to add up to cheaper.