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."

https://www.amazon.com/Pyramids-Enigma-Solved-Joseph-Davidovits/dp/0880295554

Also see a more recent paper (which I just discovered)

https://www.geopolymer.org/wp-content/uploads/pyramid_chapt1.pdf