Abstract

The Imperial Temple in Antiochia Ad Cragum is estimated to be first constructed at the end of 2nd or start of 3rd century, the time of the Severan dynasty. However, archaeological evidence also suggests that there were interventions during the Byzantine era, with burials over the temple platform, a wine press on the northern side, and walls constructed perpendicular to the temple on the southern side, use of which are unidentified. There is also a retaining wall in the back of the temple that holds the earth against erosion from the hill on the back, but it is curiously close to the Temple if built as part of original construction. The goal of this study is to investigate the authors’ hypotheses of a multi-phase use and to identify which elements found on the site may be contemporary to each other by comparing the composition of mortar samples collected from different areas, supplemented by a geoarchaeological investigation. Five samples of mortar from the various areas around the temple were collected and tested using three methods: X-ray diffraction (XRD), Scanning Electron Microscope (SEM), X-ray fluorescence (XRF) and thin section petrographic analyses. While all mortar samples include similar locally sourced hydrated lime and sand mixtures, three distinct construction styles are identified in the visual analysis of the building elements, the mortar analyses, and the geoarchaeological investigations. One sample from the walls of the wine press pool includes fibers. The unique interdisciplinary work utilizing both material analyses and geoarchaeology strengthens the conclusions that can be drawn from individual fields of study and provides more support for the hypotheses of the phased destruction and changing use of the monument.

Abstract

The history of the South African construction industry dates as far back as the Castle of Good Hope (1666), Slave Lodge (1679), Robben Island (1700), Union Buildings (1913), memorials and cathedrals, among many others. These structures represent the political, slavery, liberation and religious history of South Africa and its development throughout the years, while also contributing towards economic growth through tourism. Historical buildings stand out from the rest of the modern constructions as they portray marvellous architectural designs and unique materials used for their construction. However, due to ageing and environmental conditions, they often show critical signs of deterioration, which threaten the existence of some. In attempts to rescue these national treasures, the use of Portland cement, which is considered incompatible with the original materials, has become a common practice, not only in South Africa but abroad. To avoid disparity in materials during repair of historic structures, original material characterization is therefore recommended. This paper investigates the effects of Portland cement used on the repairs of historical masonries of the Castle of Good Hope, Cape Town and buildings on Robben Island, in South Africa. The mortar samples were collected from the Castle and analyzed using the techniques such as the visual investigation, cohesion test, microscopic and titration test. It is observed that the original lime- based mortars are not compatible with the Portland cement produced mortars. It was evident on the masonry, as the repairs are repelling from the original surfaces on these two structures.