Chemical and physical characterization of mortars and plasters from a Coptic paternoster: new excavation in the temple of Ptolemy XII, Sheikh Hamad, Athribis, Sohag, Egypt

Abstract

The present study focuses on the compositional characterization of mortars and plasters from a Coptic paternoster excavated in the temple of Ptolemy XII, Sheikh Hamad, Athribis, Sohag, Egypt. A physiochemical study using analytical techniques such as USB microscope XRPD, FTIR, DTA and SEM.EDX was carried out.

This characterization study, on one hand made characterization of the physical characteristics and chemical composition of joint mortars and different plasters used in this period as well as wall bricks and pottery water pipes; on the other hand, the developments of the hydraulic mortars or plasters of this period were discovered.

All analytical methods indicated that the brick joint mortar and whitish plaster layers made of calcite (lime) with the addition of quartz (sand) and sometimes brick gravels, while the reddish plaster layers consist of calcite (lime) with quartz (sand) and brick dust which was used as natural pozzolanic additive and that make the plasters more suitable for their use as water tank external plasters.

The most important result related to the internal dark grayish plaster layer sample of the big upper tank  is the detection of calcite, hedenbergite, quartz and hatrurite  which confirms the hydraulicity of the lime plaster.