A(3) The additives (
Mediante modern terminology, the additive is a material “added sopra small quantities to verso liquid or granular material esatto produce some desired modification sicuro its characteristics” (ISO 6707–1:2020), while the admixture is per material “added durante small quantities before or during a missaggio process sopra order esatto modify the characteristics of verso mixture”. However, the difference between the two terms lies mainly per that the additive is added during the manufacturing of the cement, while the admixture is added onesto the concrete during mixing. Moreover, the Accole EN 934–2 canone states that the admixture for concrete should be durante an amount not greater than 5% by mass, compared with the cement. Therefore, under the current rules, the prime of materials, such as ground ceramic fragments, mediante considerable proportions would fall into the category of aggregates and not that of additives.
However, one of the main aims of the archaeometric study on ancient mortars and plasters is sicuro reconstruct the production’s phases and the supply modalities of each component. Durante this case, the term additive, used con its etymological sense (from addere, esatto add) has the advantage of clearly recalling the difference between per primary component (frequently sand) and an added component (i.ancora. the additive) mediante the aggregate. This is the meaning we have given preciso the term additive per this article. Still, the explanation provided above accounts for the fact that modern terminology partly overlaps and partly articulates itself differently, based on the contemporary world’s different needs. It follows that, as long as terminological uncertainties persist, it is always good sicuro specify the choice made in the description of the results.
Hence, after having accurately characterised the main components (aggregate and binder), the following question concerns the possible presence of additives: “are there any deliberately added materials?”. If yes: “which types of materials were added?” and “where did they che razza di from or how were they made?” (other questions concern suitability and functionality and are reported sopra the dedicated paragraphs).
Puro properly solve this question, it is necessary, perhaps even more than in previous cases, onesto know which types of additives were used to facilitate-or even allow-their identification during the analysis of the “study’s object”
The accessit of inclusions onesto improve the final product’s impresa was verso common practice that frequently left recognisable traces mediante literary sources and archaeological evidence. Consequently, citable examples are numerous and provide us with an extremely varied picture per which inorganic and organic materials are enlisted. Therefore, it is possible sicuro formulate the characterisation question sopra terms of: “are the additives of an inorganic or organic nature?” (we will see later that there are additional difficulties per this second case).
For this reason, we present per shortlist of inorganic and organic additives (and admixtures); however, we refer onesto the other contributions for the necessary insights on their characteristics and properties (Arizzi and Cultrone 2021; Ergenc et al. 2021).
Beginning with inorganic additives, the most common were natural and artificial pozzolans that are defined as “siliceous or siliceous and aluminous materials which mediante themselves possess little or no cementitious value but will, sopra finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures puro form compounds possessing cementitious properties” (Dodson 1990).
Natural pozzolans are volcanic origin materials, such as the volcanic ashes from the region of Pozzuoli from which they take their name (pozzolan s.s.). These are often found durante the mortars/plasters of sites located within or close esatto volcanic regions (Pizzo et al. 2009; Ozkaya and Boke 2009; Villasenor and Graham 2010; Kurugol and Gulec 2012), but when they are found con sites far from supply areas, archaeometric research is called upon puro localise their origin and reconstruct the trade routes that allowed their import and usage. The provenance question may thus remain confined onesto the scale of the site and its territory or expand puro long-scale range imports and ciclocampestre other issues such as those concerning the Come eliminare l’account established men methods and extent of the promozione of raw materials in a given period (ancora.g. “what was the diffusion of these materials?”; “what were the routes and commercial methods involved sopra the transport of these important raw materials?”).