<HTML>Hi sandy and Anthony,
I had to drag out an old chemistry book to finally run down my confusion here, but it did the job... at least for some of the confusion ;-) I must first address the portland cement issue... my understanding of Davidovits is that it is the "zeolite" that is the natural cement that binds "such stones as sandstone, puddingstone, and fossil-shell limestone" (pg.69), and that his geopolmerization is a way to produce synthetic zeolite. Zeolites (as well as feldspar) are three dimensional silicon-oxygen networks in which a portion of the tetravalent silicon is replaced by trivalent aluminum. Note the lack of a lime component at this point. Also note the similarity in elements of portland cement which is a powdered calcium "aluminosilicate". This is not to say that lime does not come into play in making his geopolymers... but it seems to be the silicon/aluminum interaction of the zeolite that gives it the "geopolymeric" distinction. I emphasize this because he writes "This ancient mortar is far superior to cements used in construction today. The modern portland cement used to repair ancient Egyptian monuments has cracked and degraded in only about fifty years." (pg.68) He emphasizes a distinction between his geopolmers and portland cement. Even if one questions his conclusions, one has to keep in mind that this is a Phd. chemist who believes he recognizes the ability for the AEs (priests) to have been knowledgeable alchemists... with an excellent grasp of the locally available "chemicals"... even including availability to arsenic minerals "needed to produce rapid hydraulic setting in large concrete blocks." Please note that I am not trying to promote the geopolymer theory... I am simply questioning whether we are certain we are not once again short changing the AEs... even if the pyramids are not geopolymer, are we also then saying they supposedly did not have geopolymer knowledge? Not the point to some here... but to those searching for all the truths, shouldn't it be worthy of proper evaluation? Btw, good points on down about the structural integrity of "geopolymer" using shell aggregate and no huge compression pressures. Don't have a clue what the responses for those questions would be!!! Thanks guys.
Litz</HTML>
