The ancient Egyptians used cement-like materials since at least 2,500 BC. A long-standing and controversial modern hypothesis about the construction of the pyramids suggests that at least some of the stone block were cast in place rather than quarried, carved and moved to their final location.
Wonderful! I know what the MIT guys were investigating. I have treasured my copy of The Pyramids: An Enigma Solved, by the geochemist, Joseph Davidovits, for years. I particularly love this argument:
The limestone in the pyramids at Giza is 20% less dense than the limestone from the nearby quarries where it came from, Egyptologists say there must be still-undiscovered secret rooms and passages in the pyramids to account for this.
Prof. Davidovits simply comments (I paraphrase) "Everyone who has ever poured concrete knows about air bubbles."
Also see a more recent paper (which I just discovered)