Mortars and plasters—how to manage mortars and plasters conservation
01 Nov 2021-Archaeological and Anthropological Sciences (Springer Berlin Heidelberg)-Vol. 13, Iss: 11, pp 1-20
TL;DR: The use of mortars and plasters has been widespread in many cultures for thousands of years and these materials are found in the vast majority of built cultural heritage as mentioned in this paper, and they play a crucial role in the preservation of immovable heritage and must be taken into consideration when conserving historical buildings.
Abstract: The use of mortars and plasters has been widespread in many cultures for thousands of years and these materials are found in the vast majority of built cultural heritage. They play a crucial role in the preservation of immovable heritage and must be taken into great consideration when conserving historical buildings. Plasters and mortars have been extensively studied from a chemical and mineralogical point of view. The main causes and mechanisms of damage and deterioration are understood and various methods and materials have been developed for their preservation. Treatment development, testing and evaluation in the laboratory, under controlled conditions, has produced a high level of knowledge. However, there is a divergence between the results of academic-scientific studies and practice in the field. Laboratory studies typically tackle only a few variables at the time and the results cannot always be directly applied to address the complex problems that restorers face in their daily work practice. In addition, in situ conservation-restoration is extremely challenging because many of large number of variables involved cannot be controlled or modified. Following a description of the ideal “value-based” conservation process, this compilation work discusses aspects related to understanding deterioration mechanisms and planning of preventive and remedial interventions in a way that may be useful to update conservators-restorers on the status of scientific research in this field, and to guide conservation-scientists to identify unresolved issues, which require future research efforts.
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TL;DR: In this article, a review of the most widely accepted analytical techniques and physical-mechanical tests used in the characterisation of historic mortars and plasters is presented, paying special attention to aspects relating to the chemical, mineralogical and petrographic investigation of the calcium silicate and aluminate hydrated phases that may indicate the use of one or other hydraulic binder.
Abstract: Mortars are heterogeneous building materials whose raw materials, manufacturing processes and application conditions have evolved continuously throughout history. The fact that apparently small changes in the components or dosages of mortars can affect their overall performance in the masonry makes the study of historic mortars a complex task that needs to be tackled via a multidisciplinary approach, with the support of complementary analytical techniques from the field of chemistry, mineralogy, physics and engineering, among others. This review is intended to be a useful tool for researchers working in the field of archaeology and/or cultural heritage conservation, as it offers a complete overview of the most widely accepted analytical techniques and physical-mechanical tests used in the characterisation of historic mortars and plasters. Although the methods described here are common to both air-hardening and hydraulic mortars, we focus above all on the latter, paying special attention to aspects relating to the chemical, mineralogical and petrographic investigation of the calcium silicate and aluminate hydrated phases that may indicate the use of one or other hydraulic binder in historic mortars, all this taking into account and discussing the practical aspects, drawbacks and limitations of each technique. European standards for the study of mortars are also addressed in this paper.
33 citations
TL;DR: A broad and critical overview of current discussions on the potential uses and the characterization of pigments in pre-history, with a special focus on prehistoric rock art, can be found in this paper.
Abstract: This paper offers a broad and critical overview of current discussions on the potential uses and the characterization of pigments in prehistory, with a special focus on prehistoric rock art. Today, analytical approaches to pigments and paints allow us to go beyond the identification of the elemental and molecular composition of these archaeological remains, to explore also raw material procurement, transformation and use strategies of interest to investigate the technological and socio-cultural practices of prehistoric artists and their change over space and time. The paper also summarizes the palette of prehistoric artists, as well as the techniques and analytical strategies used to date to characterize prehistoric pigments and paints (colours, raw materials, binders and recipes) used in prehistoric rock art.
29 citations
TL;DR: The history of cinnabar from its first uses in burials to modern oils on canvas can be summarized in this paper, with a brief introduction on mercury and contamination issues.
Abstract: This article summarises the history of cinnabar, from its first uses in burials to modern oils on canvas. After a brief introduction on mercury and contamination issues, the article gets to the heart of the topic. First, mercury-based minerals significant for studying pigments, i.e. cinnabar, metacinnabar, hypercinnabar and calomel, are presented. Structural information and properties precede an overview of the geographic distribution of cinnabar deposits. The following section addresses the multiple uses of cinnabar, divided into funerary use, decorative use, lustre and Chinese lacquer production. The use of cinnabar for writing (ink), medicine and cosmetics is briefly described, and a shortlist of uncommon finds is further provided. The following section approaches inherent but less known topics such as cinnabar procurement, trade, production technology, application and alteration. An entire section is dedicated to calomel before concluding with an overview of the analytical methods for the characterisation and provenance investigation of cinnabar.
29 citations
TL;DR: In this article, a review of copper-based pigments used in ancient and mediaeval works of art, especially in wall paintings and/or related polychromed decorations or statues, is presented.
Abstract: Since antiquity, various copper-containing substances have been used as green and blue pigments. Their exceptional diversity, reflecting their various chemical and phase composition, chemical stability as well as their origin, makes their correct identification challenging. The review focuses on copper-based pigments used in ancient and mediaeval works of art, especially in wall paintings and/or related polychromed decorations or statues—siliceous copper pigments (Egyptian blue and green, Han blue and purple, chrysocolla), copper carbonates (azurite, malachite, blue and green verditers), copper chlorides (atacamite-group, cumengeite, calumetite), copper sulphates (posnjakite, brochantite) and—to a lesser extent—copper acetates (verdigris) and other organometallics. Particular attention is given to the necessity of the detailed study of accompanying phases which can serve as useful indicators of natural and/or artificial origin of copper pigments. Factors affecting the stability of copper pigments in wall paintings—salt attack, oxalic acid, alkalinity and heat—are overviewed. A suitable analytical approach based on complemental combination of in situ and laboratory analyses for proper identification and differentiation of copper pigments is proposed.
28 citations
TL;DR: The use of organic colourants in wall paintings has been given little attention in the past, perhaps on the assumption that they were rarely used by ancient artists as discussed by the authors, however, recent diagnostic studies brought evidence that their use was not fragmentary; on the contrary, there seems to be continuity in the centuries, at least with regard to the most widely used such as madder, Tyrian purple and indigo.
Abstract: The present contribution deals with the use of organic colourants in wall paintings, polychrome pottery and painted stone artworks, i.e. painted artworks on inorganic supports. The term organic colourants is referred to the chemical nature of these compounds but not to the way of application; therefore, organic colourants can be dyes, lakes or pigments. The use of organic colourants in wall paintings has been given little attention in the past, perhaps on the assumption that they were rarely used by ancient artists. Recent diagnostic studies, however, brought evidence that their use was not fragmentary; on the contrary, there seems to be continuity in the centuries, at least with regard to the most widely used such as madder, Tyrian purple and indigo. Sources, alteration phenomena, identification methods and analytical evidence is given for the main organic colourants with concern to red, yellow, green, purple and blue hues. Drawbacks and issues are discussed with concern to the identification techniques.
26 citations
References
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TL;DR: In this article, a little of how interest in ionic liquids grew and developed is shown.
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307 citations
TL;DR: In this article, optical microscopy is also used for damage diagnosis of degraded historic mortars and for the study of the interfacial zone, the bonding and possible reaction rims between aggregates, bricks or stone and the mortar.
282 citations
Book•
14 Dec 2004
TL;DR: A representative list of sources for the theory of scientific conservation can be found in this article, where a survey of the main sources of criticism can be seen in Section 2.1.
Abstract: Classical conservation theories (from Ruskin to Brandi) are characterized by their close adherence to Truth. These theories are currently dominant, but criticism and new alternatives are developing and gaining momentum. Three crucial notions in classical theories have been criticised: reversibility, universality and objectivity (including objective determination of damage and the notion of scientific conservation). As a result of these criticisms, emerging contemporary theory of conservation has substituted the notion of function, use or value of the conservation object for that of Truth. A representative list of sources is discussed.
231 citations