Barsoum is good at getting publicity, the author of the article is not good at researching what he's writing.
To quote a geologist friend:
The original geopolymer crowd seemed to have a whole litany of colloquial explanations for natural geological features... crossbedding was packing & settling lines that formed as the cement was pored/packed into the molds, solution vugs were air bubbles in the cement, or if all else failed the offending masonry was just a replacement block of natural limestone that was used to repair damage, etc. etc. This was coming from people who claimed through petrographic and X-ray analysis that there was a whole array of exotic minerals in the limestone that when other qualified researchers looked at the same specimen could not find any of them. What they did find was typical of a natural limestone (as well as an ancient whitewash coating on one of the surfaces) with bedding lamella and a calcite veinlet in the bulk limestone. When this was pointed out it was declared by the geopolymer crowd that the qualified researchers did not understand the geopolymer theory properly, they did not know how to analyze the samples properly, they were part of a demeaning stand against the geopolymer researchers and their scientific theory, etc. Here is a summary of the analysis against the geological claims of geopolymer theory:
7mb Pdf file:
http://www.cmc-concrete.com/CMC%20Publications/2007,%20The%20Great%20Pyramid%20Debate,%2029th%20ICMA.pdf
Jana, D. (2007) The Great Pyramid Debate: Evidence from detailed petrographic examinations of casing stones from the Great Pyramid of Khufu, a natural limestone from Tura, and a man-made (geopolymeric) limestone. Proceedings of the Twenty-Ninth Conference on Cement Microscopy Quebec City, PQ, Canada May 20 -24, 207-266.