Let me correct several points, some of which have already been pointed out by other posters:
1) Davies, who is an excellent scholar and shouldn't have to be associated with bizarre out of context fundamentally broken articles like the one linked from the summary, says that construction of public concrete buildings was a political tool used by Pompey and Julius in an escalating bid for political power. She points out that this was a factor in the end of the Roman REPUBLIC because Julius and later Augustus eventually collected enough power to bring about the establishment of the Roman EMPIRE. So while TFS, and indeed the terrible article in the ridiculously trashy "International Business Times," state that concrete led to the downfall of the empire, their source instead says that concrete was one of many factors that led to the FORMATION of the empire. In otherwords, TFS and TFA both state exactly the opposite of what the source stated.
2) This statement about concrete contributing to the founding of the Roman Empire has been present in high school textbooks for at least a hundred years. It's not news.
3) The real news that prompted the article is also misrepresented. French scholars recently published a paper pointing out that the level of lead in Roman drinking water wouldn't have had significant side effects. Both TFS and TFA state that the previous theory on the fall of the Roman Empire was that it was due to lead poisoning. This isn't even remotely accurate. Yes, crackpots have published claims that lead poisoning led to degenerate Romans. In no way has it ever, not even for a moment, been accepted by scholars as "the cause" of the Roman Empire's fall. There is no single cause of the fall of the Roman Empire. It wasn't an asteroid or aliens or disease - it lasted for a ridiculously long time and eventually fell apart over the course of about 1500 years. The number of scholars who believed that the Roman Empire "fell" because of lead poisoning was similar to the number of paleontologists who believe the dinosaurs died out because of Noah's flood.
It's too bad that the simple debunking of this crackpot theory in the study published by the French team was reported in the International Business Times by such an unintelligent reporter, and even worse that Slashdot picked the story up without recognizing the inaccuracies that any 8 year old with a 100 IQ would be able to detect.
A couple months ago Slashdot went through a transition. It became useless for awhile because every article was flooded with complaints about the new site design, but I think that there was a simultaneous shift toward poorer editing and lower quality story submissions. Maybe the cleverer Slashdot posters did what I have and mostly stopped paying attention. I've spent 10 years laughing at the people who post about how Slashdot declined since the good old days, but recent evidence shows that the decline is real and undoubtable. Perhaps the editors suffer from lead poisoning.