My understanding is that cement is an ingredient of concrete and is what binds together the other ingredients into the final product known as concrete.
The point I was attempting to make was, the egyptians did not make that conceptual leap, to the best of our knowledge.
They used a limestone mortar but never went so far as to add an aggregate of any kind..
They did, however, make small castings of statuary and some decorative items.
It was not until the Romans that concrete was conceived of and used in large scale projects such as architecture and other structural elements..
The Romans use of concrete involved different formulations as well..
One of their earliest known projects was the casting/pouring of concrete for fish pens.
They used a concrete containing a type of volcanic ash ( like pumice ) which allowed them to create a type of water-proof concrete.
Some of those concrete pens still exist today and are still water proof.
Some Roman construction has been shown to use wheat, cooked into a paste, and added to their mortar to make it stickier. ( Interestingly, the Chinese used a similar trick using rice paste in their mortar at about the same period in history )
Romans built St. Peter's Basilica which has a concrete dome, which was the largest free standing ( unsupported ) dome in the world well into the 19th century. ( maybe into the 20th, not sure )
Additionally, Romans used "reinforced" concrete in some projects, IIRC.
Much of their knowledge was lost, as mentioned by another FReeper earlier in the thread.
Portland cement and use of reinforced concrete would not be developed until the 20th century.