bas-relief in tomb of block mouldingSlide_0042_FullPhoto of ceiling in Pyramid Chamber

The Pyramids were not built with carved large blocks of limestone transported from a distant quarry by a huge number of slaves (an impossible task in the construction time of 20years for the Great Pyramid). The blocks were actually poured on site into molds as shown in the above wall painting from a tomb dating to around the same time as the pyramids. The poured material was like a concrete or mortar made up of an aggregate and a binder which was mixed with water and set over time. The matrix limestone (CaCO3 which contains fossils) came from a young soft deposit in a close-by wadi. The binder was a geopolymer material made from Natron (sodium carbonate-NaCO3), lime (CaO ), wood ash (contains some KOH) and kaolin clays. The mixture of Natron and lime with water gives calcium carbonate (CaCO3) and caustic soda (NaOH) which in turn reacts with the clay. The material sets and strengthens over a few days so the mold can be stripped and more adjoining blocks poured. As the material dries it becomes indistinguishable from natural limestone. The Great Pyramid had a veneer of polished marble slabs which did come from a distant quarry. The slabs were held in place over the blocks by a mortar which can be identified by chemical analyses as different from the marble slabs and the molded limestone blocks.
The builder of the Pyramids was Imhotep. Imhotep (…Imhotep) was not only one of the first recognised Civil Engineers but also one of the first (and great) chemical engineers (the first was probably the person who discovered Cupellation to separate silver from lead around 5000BC).

The Wiki entry about Imhotep mentions he was Maker of Vases in Chief. Look at this vase

Egyptian Cast Gneiss Vase

No one could carve this even today with diamond tipped tools. It has been molded from a thin sheet of geopolymer bonded material with the edges gently folded over. It was then probably fired at a low temperature (around 300C) to set.

2 thoughts on “Pyramids

  1. Nicely done. It reminds me that I need to get back to trying my hand at making some of that geopolymer stuff 😉

    BTW “craved large blocks” perhaps CARved ? (Feel free to delete this line once noted).

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