D-99 Can Neutron Diffraction Contribute to Elucidating How the Great Pyramids of Giza Were Built?

Abstract

How the Great Pyramids of Giza were built has remained an enduring mystery. In the mid1980s, Davidovits [1] proposed that the stones used to build the pyramids were, instead of being quarried, cast in situ using granular limestone aggregate and an alkali alumino-silicate-based binder. Hard evidence for this idea, however, remained elusive. In a recent publication, Barsoum and coworkers compared a number of pyramid limestone samples with six different limestone samples from possible quarries in the vicinity of the pyramids by means of scanning and transmission electron microscopy [2]. The pyramid samples contained microconstituents with appreciable amounts of Si in combination with elements, such as Ca and Mg, in ratios that do not exist in any of the potential natural limestone sources. The intimate proximity of the microconstituents suggests that at some time these elements had been together in a solution. Furthermore, contrary to the natural limestone aggregates, the microconstituents with chemistries reminiscent of calcite and dolomite—not known to hydrate in nature—were hydrated in the pyramid samples. Apart from its implications for Egyptology, studying these materials also provides insight into an ancient geopolymer concrete that might evolve into an affordable, environmentally friendly and durable building material. In this presentation we will report preliminary results of an investigation of the same samples by neutron diffraction utilizing the HIPPO instrument at LANSCE. These experiments complement the spatially resolved electron diffraction experiments with bulk qualitative and quantitative phase analysis, and texture.