Collete,
Here is my take. I am ok with the concept of a concrete pyramid. However, Davidovits and Morris and Barsoum have not made the scientific case.
For 20 years, Davidovits was claiming he could make a pyramid with "Kaolin Clay" as the substitute for "Pozzolanic Ash". Last year, Barsoum, who was working with Davidovits published a paper saying there was no "Kaolin Clay / Alluminum" in his samples. Hence,
Barsoum discredited the science of Davidovits. Even IF the pyramids are concrete, without the Alluminum, it is not a "Geopolymer"; it would be something else.
Since then, Barsoum has
conjectured that maybe there are other ways of creating concrete with the substances available in Giza. However, no new formula has been published or put to the test. Even IF Barsoum is right, his claim is that the upper half of the pyramids are concrete, while the lower half is carved... a signifigant change in position from Davidovits and Morris; some would call this a moving target.
Archae is an extremely knowledgeable critic on the subject. The science gets pretty complex. And Barsoums paper seems to focus on the 1% impurities in the rock, rather than the whole rock.
Until a new formula is put forth, this topic/hypothesis is probably a waste of time, as the burden of proof always lies on the theorist and not with the critic.
Rich