Mineralogical-Petrographic and Physical-Mechanical Features of the Construction Stones in Punic and Roman Temples of Antas (SW Sardinia, Italy): Provenance of the Raw Materials and Conservation State

Abstract

The Antas site (SW Sardinia, Italy) is of fundamental cultural importance because it testifies the presence of Nuragic, Punic and Roman civilizations from the second millennium to the third century BC. This work focuses on the Punic and the Roman temples and aims to define their conservation state and provenance of construction materials through their minero-petrographic and physical-mechanical characterization. In addition, artificial geomaterials used in restoration works comprising a partial anastylosis and a consolidation intervention on the monument, were investigated to evaluate the aesthetic, petrographic and petrophysical compatibility with the original materials. The results indicate that Punic builders preferred to use a porous sandstone coming from at least few kilometres away from the site. By contrast, Roman builders opted for the use of the less porous and harder local metadolostones, more difficult to quarry and to hew but promptly available in the surrounding area. The Roman temple still preserves decorative architectural elements (as the Pronao threshold and the mosaic tesserae) whose source is definitely not local, suggesting the import of these materials. As regards artificial materials, a new material was found within the Punic temple consisting of a sandstone-like rock (i.e., lime based sandy-conglomeratic geomaterial) and characterized by higher mechanical strength and lower porosity.

An Integrated Approach to Using Sheep Wool as a Fibrous Material for Enhancing Strength and Transport Properties of Concrete Composites

“…The amount of fiber in the concrete matrix could determine the air void content, affecting the concrete strength. In addition, the rise in porosity can be associated with the growth of micro-cracks in the specimen and, therefore, poor fiber–matrix bonding and lower strength [ 30 , 31 , 32 ]. Figure 6 demonstrates that fiber additions resulted in greater pore size and lower strength, indicating these internal physical changes.…”

Mining Exploration, Raw Materials and Production Technologies of Mortars in the Different Civilization Periods in Menorca Island (Spain)

“…The resistance to punching is higher than the degraded mortars based on lime and cocciopesto. This is explained by a lower open porosity of these gypsum mortars (24-39%), resulting in lower bulk density values (1.42-1.47 g/cm 3 ) and higher values of the real density (2.75-2.76 g/cm 3 ) explained by the presence of bassanite (2.73 g/cm 3 ) and above all dolomite (2.84 g/cm 3 ) and magnesite (2.98 g/cm 3 ). The porosity values are in any case quite high and even in this case it is possible that the degradation induced by the marine aerosol and the constant daily hygrometric variations (given the proximity of the sea) have led to a chemical-physical alteration of the lime-gypsum binder, although it was mainly concentrated on its surface of mortar.…”

“…Since ancient times, mineral prospecting has been a very important activity allowing the populations to recognize the georesources offered by their territories, to be used as construction materials and/or for the artefact production. Several studies, during the last sixty years, have been addressed to the determination of the provenance of raw materials, including stones [1][2][3], ceramics [4][5][6], glasses [7][8][9] and mortars [10][11][12][13][14][15].…”

“…If, on the one hand, high-value and/or rare materials were imported even from far source regions if not available on site (see for instance [16,17]), on the other hand low-value materials were mainly provided from local or nearby sources (as in the cases of [3,18,19]). However, the supply of geomaterials from local outcrops was not always so easy, as the Minerals 2022, 12, 218 2 of 33 territory sometimes did not offer suitable materials for the work to be carried out.…”

Lime and Cement Plasters from 20th Century Buildings: Raw Materials and Relations between Mineralogical–Petrographic Characteristics and Chemical–Physical Compatibility with the Limestone Substrate

“…The raw materials, the calcination technologies and the building techniques evolved in different ways from one locality to another, leading each place to obtain its own style and best practices [2]. A plethora of papers deals with historical mortars, stones, and other geomaterials, with all of their related aspects, including archaeological inferences and significance [5][6][7][8][9][10][11][12][13][14], raw materials provenance [15][16][17][18][19][20][21][22][23][24], the chemical, mineralogical and physical properties [25][26][27][28][29][30][31][32], degradation issues [33][34][35][36][37][38], and conservation/restoration techniques [39][40][41][42][43][44][45].…”