We have known about the composition of Roman Concrete for a long time, the main difference is we trade long term strength for a shorter curing time. For an excellent dissection of this recent round of "secrets technology of the ancients that our modern science only now is beginning to understand" check out this reddit thread, it has quite a few engineering students and professionals chiming in and I learned quite a bit from it. http://www.reddit.com/r/science/comments/1fohl2/berkeley_dis...
People knew about Roman concrete. According to CivE people in the thread, the problem is that volcanic ash isn't present everywhere and it sets much slower than Portland cement.
This study was paid for by a Saudi Arabian University, and as mentioned in the article, Saudi Arabia happens to have a lot of volcanic ash.
In India there is a huge demand (quite outstripping supply) for flyash bricks, made from the industrial byproduct of coal burning furnaces (which supply >50% of India's power supply). They closely resemble the properties of volcanic ash.
The supply is likely to go down even further as we transition into gas furnaces and nuclear power.
One downside of building things using flyash that people are going to be around a lot is that it increases radioactivity exposure. I'm not sure how it compares to granite though, but it can be fairly significant.
Of course ancient Roman concrete is better than what we have now. The ancient Roman concrete that wasn't better than what we have now, didn't survive to today. There was probably a wide range of random kinds of concrete, and a 2000-year experiment has told us which of those random kinds was the best.
More or less... There are Roman-era writings describing their most common method of making concrete.
What made me flabbergasted is that only NOW someone say this is news...
Seriously, if the thing was written down already 2000 years ago, why noone bothered to test?
Or they did, but other reasons made corporations not use it?
My dad is a engineer, and he told me that some old bridges here in Brazil made with such concrete are REALLY HARD to explode for some reason...
I don't know if that is the case with the bridge that Luisa Erundina tried to explode in São Paulo, but here we have a bridge that there was 4 attempts to explode by a specialized demolitions engineering company, and it barely got dented.
EDIT: of course, most common for important buildings... Poor people won't use that sort of concrete, one of the ingredients is volcanic ash, and you cannot find volcanic ash everywhere, it was probably more or less expensive.
The formula for (Roman) concrete was lost for centuries or the Romans didn't share it which also makes sense if you're a militaristic society why give away the secret to concrete?
And it's only recently the secret of Roman concrete was discovered.
Also I don't think Roman concrete is exactly the same as what we think of concrete it's not like the Romans poured it out into forms as is done today.
Realistically, it can't replace most uses of concrete. Roman concrete takes years to reach full strength. The stuff we use is close to full strength in days.
It is remarkable that with all of today's technology and advances, there are still areas to be found where we have yet to match the engineering prowess of thousands of years old civilizations.
I would not call it "engineering prowess". I would call it "experimentation" or "luck". The Roman Empire lasted 450 years, so they had plenty of time for experimentation, and it was near plenty of volcanic ash, which provided ample opportunity to luck into a good formula.
Obviously they came up with something good, and deserve credit. But to call that a triumph of Roman engineering over modern engineering? If I grew up in a land possessing an abundance of of nitrate, charcoal, and sulfur, would you proclaim how advanced my science was, if I came up with gunpowder?
Environment plays a huge role in everything, constructing superior concrete is no exception. That doesn't preclude it from being useful at the end of the day...
In this case it's not engineering prowess, however, it's just dumb luck: they had plenty of volcanic ash to work with, we don't.
Another example is Roman pottery. By sheer coincidence the clay they used was of exceptionally high quality (extremely fine particles, IIRC) so Roman pottery is extremely hard and durable, much harder and durable than we can make pottery today. Unfortunately, there was only one source of this clay (somewhere on the coast of Italy) and the Romans depleted it.
This is not news, I am not in the field and have known it for ages. So have cement makers that make specialized cement.
The immediate money will be in making a special liquid that can be sprayed in existing concrete building to make them last longer. If I'm building a 100 story tower in NYC, why spend, say x% more, when the building is likely to be sold 20 times in those 100 years? Now if I'm a state government with crumbling bridges, I'm extremely interested to make them last another 10-100 years.
They are many companies already like Penetron that have special solutions to stop water penetration. MIT, IIRC, figured out how to stop the chemical reaction in concrete, making it last a theoretical 16,000 years. http://web.mit.edu/newsoffice/2009/creep-0615.html
