A(3) The additives (

Per modern terminology, the additive is verso material “added per small quantities esatto verso liquid or granular material onesto produce some desired modification onesto its characteristics” (ISO 6707–1:2020), while the admixture is verso material “added per small quantities before or during verso missaggio process in order sicuro modify the characteristics of per mixture”. However, the difference between the two terms lies mainly con that the additive is added during the manufacturing of the cement, while the admixture is added esatto the concrete during mixage. Moreover, the Adouci EN 934–2 norma states that the admixture for concrete should be sopra an amount not greater than 5% by mass, compared with the cement. Therefore, under the current rules, the accessit of materials, such as ground ceramic fragments, durante 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 onesto reconstruct the production’s phases and the supply modalities of each component. In this case, the term additive, used con its etymological sense (from addere, onesto add) has the advantage of clearly recalling the difference between a primary component (frequently sand) and an added component (i.e. the additive) con the aggregate. This is the meaning we have given sicuro the term additive sopra 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 to specify the choice made sopra 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 from or how were they made?” (other questions concern suitability and functionality and are reported sopra the dedicated paragraphs).

To properly solve this question, it is necessary, perhaps even more than in previous cases, puro know which types of additives were used onesto facilitate-or even allow-their identification during the analysis of the “study’s object”

The adjonction of inclusions esatto improve the final product’s prova 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 preciso formulate the characterisation question in terms of: “are the additives of an inorganic or organic nature?” (we will see later that there are additional difficulties durante this second case).

For this reason, we present verso shortlist of inorganic and organic additives (and admixtures); however, we refer puro 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 con themselves possess little or in nessun caso cementitious value but will, durante finely divided form and sopra the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds quiz jdate 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 sopra the mortars/plasters of sites located within or close to volcanic regions (Noia et al. 2009; Ozkaya and Boke 2009; Villasenor and Graham 2010; Kurugol and Gulec 2012), but when they are found mediante sites far from supply areas, archaeometric research is called upon sicuro localise their origin and reconstruct the trade routes that allowed their import and usage. The provenance question may thus remain confined puro the scale of the site and its territory or expand to long-scale range imports and ciclocross other issues such as those concerning the methods and extent of the marketing of raw materials per a given period (e.g. “what was the diffusion of these materials?”; “what were the routes and commercial methods involved mediante the transport of these important raw materials?”).