Proposta di un nuovo protocollo comune per la diagnosi, l'analisi dei depositi inorganici ed il consolidamento del legno archeologico imbibito in Cina ed in Italia.

Progetto comune di ricerca

Responsabili di progetto: Nicola Macchioni, Dawa Shen
Accordo: CINA - CACH - Chinese Academy of Cultural Heritage
Bando: CNR/CACH triennio 2019-2021 2019-2021
Dipartimento: Scienze bio-agroalimentari
Area tematica: Scienze bio-agroalimentari
Stato del progetto: Nuovo

Proposta di ricerca

In the last three years, the joint research group from CNR-CACH did some basic research and technology exchange on waterlogged archaeological wood conservation. On site investigation was conducted. The group members visited more than 10 museums, institutes and archaeological sites related to archaeological wood conservation both in Italy and China. Three symposia were hold in Italy and China separately. The conservation technologies used in China and Italy were discussed and compared in detail. The related standards in Italy and Europe were translated into Chinese and Chinese standards were translated into English. Some wood samples were analyzed and two papers were published.
Based on the work of the ongoing bilateral project, current situation of waterlogged archaeological wood conservation are summarized both in Italy and China.
In recent years, with the development of conservation of marine archaeological wood in China, CACH set up the systematic methods for inorganic deposit analysis, including ion chromatography, X ray fluorescence, X ray diffraction, Scanning Electron Microscopy-Energy Dispersive Spectroscopy, and Inductively coupled plasma spectrometry etc. In Italy, there is little research about the inorganic deposit in archaeological wood, and there are no related systematic methods.
For the aspect of conservation (including consolidation and dehydration), PEG, Kauramin, vacuum freeze drying are usually used in Europe, especially the PEG methods are used and deeply all over Europe. In recent years, some new materials have been tested including trehalose, and sucralose, also sugar alcohols methods are progressively diffusing in Italy. In China, many methods and materials were tested, including PEG, sugar, sugar alcohol, poly alcohol and glyoxal. But, both in China and Italy, when evaluating the efficiency of consolidation and dehydration, there are only few indexes such as dimensional stability and moisture absorption which are used, at laboratory level. Also, there are no broadly accepted criteria to adopt a new consolidant when treating waterlogged archaeological wood. The status and the performances of treated wood is not yet fully described.
Following what emerged from the previous successful bilateral project that ends this year, it is considered necessary to move on to a second phase of joint commitment in research activities on three fields in which the development of common activities seems to be crucial:
- Diagnosis and characterisation of the material (analysis of the inorganic material present), considering a common starting point the Italian standard UNI 11205:2007, that would drive to the insertion of new qualitative and quantitative analytical methodologies of inorganic compounds (EDAX, XRF, ICP mass); improvement of FTIR methodologies for the quantitative analysis of organic compounds (cell wall residual composition). In addition to this, also non-conventional methodologies to assess the mechanical properties of waterlogged wood (e.g. Dynamic Mechanical Analysis DMA) could be of interest, as well as the dating of artefacts by means of methods that are well-established in dry or waterlogged contexts, such as dendrochronology or radiocarbon analysis. From a dendrochronological point of view, this could be a good opportunity to establish long reference chronologies. On the other hand, while in the project these techniques will be considered, their introduction as standard methods will be considered after an attentive analysis of competences involving other Chinese laboratories potentially interested in their use.
- Development of pre-treatment methodologies for artefacts, treatment that will prepare the findings to consolidation. The consolidation carried out without taking this phase into account may in fact lead to subsequent problems on the consolidated objects, due to the interaction between archaeological wood-inorganic fraction-consolidant. The project will consider spreading the experience developed in China to the Italian partner, adopting the diagnostic techniques and methodologies described in the previous point to characterise wood subjected to pre-treatment phase. Only the methods not affecting original characteristics of wood will be proposed as common protocols.
- The development of new consolidating products for archaeological wood, together with the related consolidation protocols, is becoming more important, considering that currently used products (such as PEGs and Kauramin) seems to evidence some technical inconveniences whereas sugar alcohols could have problems of commercial availability in the next future. Equally an important delivery will be the development of a common protocol for the control of the effectiveness of the intervention; for this purpose, samples will be selected and exchanged to carry out the same protocol in different laboratories. Some consolidants products that seem worth of a common trying in their effectiveness are glyoxal and low environmental impact consolidants, such as proteins (e.g. keratin) and crystalline nanocellulose. This work will allow defining the general characteristics that a newly introduced consolidant must possess to be considered suitable for the treatment of archaeological wood.
In CACH, some scientific instruments such XRD, XRF, SEM-EDS, ICP could be used in the inorganic deposit analysis. At IVALSA, optical microscopy and wood sampling system could be used in anatomical observation, FT-IR could be used in degradation characterization, and DMA could be used in the evaluation of consolidation. Still in IVALSA, a tree-ring measurement station (LINTAB) could be used for analysing tree rings and constructing tree-ring series. Both laboratories have facilities to characterise the efficiency of consolidated wood (climatic chambers, creep-related aspects, long-term emissions etc.).

Obiettivi della ricerca

Waterlogged wood samples from 1-2 typical archaeological sites will be selected, then sampling, analysis, desalination, de-ironing (or preliminary metals removal), consolidation and dehydration experiments will be carried out in both laboratories, and characterisation protocols will be drafted, including:
1. Samples will be analyzed anatomically, physically and chemically previous to any treatment. Samples will be dated through dendrochronology and C14 methods. Decay characters of wood samples from Italy and China will be compared and diagnostic protocol will be drafted.
2. Analysis of the inorganic deposits in wood samples will be analyzed and removed. A pre-standard for desalination/deironing will be drafted, and the characteristics of woods evaluated again and compared with those preliminary to treatments for inorganic deposits. The most successful protocols will be used for amending the Italian National standard UNI 11206:2007.
3. Samples consolidation with common protocol in both laboratories and dehydrated; the various treated samples will be analysed to assess the conservation efficacy (scanning before and after treatment to assess the shape and volume variations, observing at SEM, chemical analyses aimed at assessing the state of preservation and emissions, creep-related aspects after treatments etc.); then a protocol for consolidation and dehydration will be drafted.
Amending of existing standard, formulating pre-standard and publishing scientific papers.

Ultimo aggiornamento: 09/05/2025