1,720,977 research outputs found
Non-invasive analysis of soluble salts. Preliminary results on the case study of Casa di Diana Mithreum (Archaeological site of Ostia Antica - Italy)
No full textThe knowledge of materials and microenvironment has a fundamental role on the preservation of Cultural Heritage. Thermohygrometric conditions as well as a direct contact with water are surely a cause of direct or indirect, i.e. as carrier of soluble salts, of degradation.
A new method for a non-invasive analysis of soluble salts (Japanese paper or cellulose pulp) [1], even if already under study, was applied to a wall of the Casa di Diana Mithreum (Archaeological site of Ostia Antica - Italy) and compared with the method currently in use, invasive and relatively dated (UNI 11087/2003). The proposed method only differs from the above cited UNI in the sampling procedure that, further, is not clearly described there. According to the ruled method, Ionic Chromatography (IC) and conductivity measures were performed on the samples while further pH and redox measures were done together with a characterization of materials (bricks and mortar) by Optical Microscopy in polarized light (MOP) and X-ray diffraction (XRD).
Results coming from a microclimatic campaign are object of a paper ready to be submitted for publication while here we present those regarding the soluble salts analysis together with the material characterization; obviously a correlation between all data will be looked for in a next future
The influence of environmental parameters in the biocolonization of the Mithraeum in the roman masonry of casa di Diana (Ostia Antica, Italy)
No full textA MICROCLIMATE STUDY ON HYPOGEA ENVIRONMENTS OF ANCIENT ROMAN BUILDING
No full textRoman hypogea, vernacular settlements or crypts, are underground places characterised by specific and unique challenges (RH < 90% and almost constant temperature throughout the whole year) related to their relative isolation from the outdoor environment. These sites often require adequate monitoring tools providing complete environmental information in order to carry out appropriate strategies for scheduling routine maintenance and designing suitable layouts for their preservation.
In this work we present the results of a carefully planned thermo-hygrometric monitoring campaign conducted in a peculiar Roman building (130 CE), the "Casa di Diana" Mithraeum, sited in Ostia Antica (archaeological site, Rome-Italy), with the aim of characterising the indoor environment as the structure suffers of several conservation problems (biocolonisation, efflorescences, evaporating and condensing cycle for wall-building materials).
The campaign involving multipoint continuous measurement was carefully planned to better describe this micro-clime. In addition to underground environmental data available in literature, we have also performed, as a checkpoint control, a thermo-hygrometric monitoring campaign in the "Terme di Mitra" Hypogeum, a few meters from the "Casa di Diana".The recorded data was analysed by multivariate statistical and chemometric analyses.
The results brought to light the presence of different microclimates (three areas) within a single Mithraeum: a room(pre-Mithraeum) and an area (Mithraeum: 2-4m) present a thermo-hygrometric environmental behaviour in accordance with a semi-confined environment, another area (Mithraeum: 1-2 m) behaves accordingly with underground environments (although it cannot be described as such), and the last area (Mithraeum: 0-1 m) where was recording RH values close to saturation (96-99%), associated with non-ventilated areas where the rising damp is "held" and not dispersed, describing an own micro-clime, comparable to a "small greenhouse".
This study has allowed to identify some critical areas in view of planning future conservation solutions, without exporting the artefacts kept inside. (C) 2016 Elsevier B.V. All rights reserved
An innovative multidisciplinary methodology to evaluate the conservation state of cultural sites as a whole: “Casa di Diana" (Ostia Antica, Italy)
Full text linkArchaeological sites, perceived as open museums, are particularly complicated to study because of the extensive number of environmental stressors affecting their conservation state. Diagnostic methodologies can easily omit some of them, causing irreparable and inestimable damages to these sites.
In this sense, multidisciplinary studies seem to constitute the most suitable approach to understand the decaying processes that occur. Up until now, these types of studies have been applied within local programmes, leading to loss of strategic output, risk of duplication and reduction in the international competitiveness of the research.
Therefore, in this Joint Doctoral Thesis, a new protocol for the preservation and accessibility of the archaeological sites, based on the synergic combination of physical, geological and analytical chemistry methodologies, is presented, in order to understand the sites as a whole. The project was born in 2012 within a multidisciplinary study on Ostia Antica Mithraea, as the result of my master degree. Successively, thanks to an international cooperation (Italy-Spain) and institutional effort (National and International Research centers and Departments) it was possible to combine different disciplines developing a new analytical approach. The final aim of this approach was assess the conservation state of the building under study, pointing out the areas most at risk, resolving important issues emerged during the investigation, and identifying the origin of the decay, suggesting also possible repair tools.
The diagnostic protocol consists in a dynamic model, developed as a pyramid that includes three steps or levels that can be summarised into anamnesis (the state of art, the macroscopic observation on both environment and materials), analysis (the development of a protocol that includes the investigation actions that lead to the identification of damage’s sources) and a conservation step (the real state of conservation of the site under study). This last action also considers some suggestions for a future and global conservation and lays the “ad-hoc designing” to create a whole conservation plan. The final goal is the conservation, safeguard and “usability” of open museums or cultural sites in general, thanks to the protocol flexibility, organised in steps procedures. The base of the pyramid is built on an initial hypothesis based on the “content and container” axiom, the relationship between the environment and the materials.
In order to validate the proposed diagnostic protocol, the model has been implemented in a complex building, the “Casa di Diana” Mithraeum, a Roman masonry dated 130 CE, found in Ostia Antica (Italy), the port of the old city of Rome, obtaining a well-developed pyramid. The rising damp represents the key between all the actions successively developed, both geophysical and chemical surveys, and is the result of a synergic interaction.
Thanks to the well-planned multi-analytical procedure, the results obtained point out towards the rising damp and acids gases as the main environmental stressors. It was possible to associate the rising damp to the presence of freshwater at shallow depth, which causes the preliminary hydration phase on bricks, and the attack of the wall-building materials by the atmospheric acid gases through dry deposition mechanism. Furthermore, the results obtained by non-destructive spectroscopic analyses have led to the hypothesis that the observed yellow bricks could date back to a different historic period, for instance Byzantine, which corresponds to the last period of utilization of this house, while the red bricks derive from the Roman period.
In addition to the new protocol, each methodology is characterised by several novelty keys, obtaining in this sense, 12 research articles published/reviewed on important international journals.
Some processes of this multidisciplinary study involve an important economic effort, but the present method allows making an objective decision, through a solid analytical protocol, which has an important value in the management of Cultural Heritage
Three-dimensional electrical and seismic tomography for assessing the state of conservation of a masonry wall
No full textGeophysical non-destructive testing has been applied worldwide during last decades for understanding the inner
geometry, the constructive materials and the degree of conservation of ancient buildings affected by the ravages of time,
human interventions or natural phenomena (e.g. Polymenakos et al. 2005; Tsokas et al., 2013).
The integrated approach presented in this work encompasses the use of Electrical Resistivity Tomography (ERT) and
seismic tomography aiming to assess the current state of conservation of a Roman masonry building, named "Casa di
Diana", located at the Ostia Antica archaeological site (Rome, Italy).
Three-dimensional ERT and seismic tomography investigations were focused on an inner wall, made in opus
caementicium, prone to both rising damp and cracking phenomena, in order to reconstruct a 3D model where anomalous
zones would be highlighted. ERT dataset were inverted with the VEMI interface (De Donno & Cardarelli, 2015), while
seismic tomography inversion was performed by means of the algorithm after Cardarelli & Cerreto (2002).
Results show that low resistivity and P-wave velocity values can be associated to the presence of the inner mortar,
while higher values of both parameters were observed for the existence of the outer brick component. Overall, with
reference to a previous work where a small-scale sample of a Roman masonry wall was analysed in the laboratory using
seismic tomography (Cardarelli & de Nardis, 1999), the brick part seems to be in good conditions (optimal VP=1400 m/s,
recovered VP=1300 m/s), while the low velocity values of the mortar (optimal VP=500 m/s, recovered VP=250 m/s) can
potentially represent an anomaly due to degradation phenomena. Therefore this approach can be employed to reconstruct
a 3D model of an archaeological wall in order to plan the recovery actions
Assessing the State of Conservation of a Masonry Building through the Combined Use of Electrical and Seismic Tomography
No full textAn integrated geophysical approach encompassing electrical resistivity and seismic tomography
investigations is presented in this work, for assessing the current state of conservation of a Roman
masonry building located in the Ostia Antica archaeological site (Rome, Italy), affected by rising damp
and cracking phenomena.
A preliminary three-dimensional electrical survey aims to detect the foundations and understand the range
of variation of the resistivity at the study site. High-Resolution electrical and seismic tomography lines
were later acquired on an inner wall, prone to both rising damp and cracking. The combined use of
electrical and seismic tomography allows us to obtain a high-resolution map of the wall made in opus
caementicium, where low resistivity and P-wave velocity values can be associated to the presence of the
inner mortar, while higher values are probably due to the outer brick component. Overall, with reference to
a previous laboratory work on a Roman masonry sample analysed using seismic tomography, we rate the
brick part in good conditions while the low velocity values of the mortar can potentially represent an
anomaly due to degradation processes. This approach can be employed to reconstruct a three-dimensional
model of the surveyed wall in order to plan recovery actions
Geophysical and geochemical techniques to assess the origin of rising damp of a Roman building (Ostia Antica archaeological site)
No full textA combined approach based on geophysical and geochemical analyses was carried out to determine the sources of rising damp in “Casa di Diana”, a Roman building located in the Ostia Antica archaeological site (Rome, Italy). The studied building is characterized by high humidity values (closed to saturation, > 90% RH) with significant efflorescence and sub-efflorescence phenomena on masonry walls.
Electrical Resistivity Tomography was performed both inside and outside the building to understand the geological setting, to estimate the freshwater-salt water interface, to locate building foundations and consequently, to evaluate the interaction between the structural elements and groundwater. On the other hand, local shallow groundwater was analysed for soluble salts and isotopic analysis (δ18O) to identify the origin of solutes, to isolate the main factors determining the isotopic content and to investigate the aquifer behaviour in terms of movement and distribution processes. The water samples were collected from one well and one tank sited inside and outside the house, respectively.
The geophysical inverted models, were able to detect a freshwater aquifer at the shallower depths (2–5 m) in correspondence to the Roman foundation walls (extended at depth up to 8 m), while below (8–10 m from surface) the salt water presence is likely. The chemical analysis confirmed that groundwater is slightly mineralized even though the salt concentration can be compatible with an interaction with sea salts, maybe due to the depth of the foundation walls.
Therefore, the proposed approach is suitable for understanding the causal relationship between the observed phenomena, assessing the current degree of conservation of the archaeological site and consequently planning the recovery actions
The orientation of the Mithraea in Ostia Antica
Full text linkWe conducted an investigation on the orientations and geometrical content of the Mithraea of Ostia Antica.
A geometrical CAD study based on the most reliable plans from the Archives of the Sovrintendenza Speciale
per il Colosseo, il MNR e l’Area Archeologica di Roma – Ostia Antica, aside with the identification of geometrical
and numerical schemes and associated length units, allowed us to identify the axes of the Mithraea. Then the
orientations of the axes were measured on field by means of a professional compass with ± 0.5° uncertainty.
The distribution of these measured azimuths follows the topography of the city. On the contrary, the Decumanus,
the main street of the town, presents an indubitable orientation toward the Winter Solstice Sunset.
This was ascertained by measuring the coordinates of four significant points along the street with the help of
a palmar Trimble GPS which averages 100 measures per point.
The exceptional density of Mithraea in Ostia led us to suppose that a symbolic cosmic-solar value is to be
searched in the orientation as a whole of the town itself, founded half a millennium before the first presence
of Mithraism in Rome. The Decumanus could be considered the very holder of this symbolic value with its
orientation toward the Winter Solstice Sunset, possibly making of Ostia a very special place for Mithraicism
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