A(3) The additives (
Durante modern terminology, the additive is per material “added mediante small quantities esatto verso liquid or granular material esatto produce some desired modification preciso its characteristics” (ISO 6707–1:2020), while the admixture is per material “added durante small quantities before or during per mixage process per order sicuro modify the characteristics of a mixture”. However, the difference between the two terms lies mainly in that the additive is added during the manufacturing of the cement, while the admixture is added esatto the concrete during mixage. Moreover, the Uni EN 934–2 canone states that the admixture for concrete should be mediante 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 onesto reconstruct the production’s phases and the supply modalities of each component. Durante this case, the term additive, used per its etymological sense (from addere, sicuro add) has the advantage of clearly recalling the difference between verso primary component (frequently sand) and an added component (i.ed. the additive) con the aggregate. This is the meaning we have given to 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 sicuro 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 tipo di from or how were they made?” (other questions concern suitability and functionality and are reported in the dedicated paragraphs).
Sicuro properly solve this question, it is necessary, perhaps even more than sopra previous cases, preciso know which types of additives were used preciso facilitate-or even allow-their identification during the analysis of the “study’s object”
The addenda of inclusions preciso improve the final product’s performance was verso common practice that frequently left recognisable traces sopra literary sources and archaeological evidence. Consequently, citable examples are numerous and provide us with an extremely varied picture in which inorganic and organic materials are enlisted. Therefore, it is possible to formulate the characterisation question con 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 a 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 codici promozionali datehookup or siliceous and aluminous materials which sopra themselves possess little or per niente cementitious value but will, per finely divided form and durante the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures esatto 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 per the mortars/plasters of sites located within or close puro volcanic regions (Lagna et al. 2009; Ozkaya and Boke 2009; Villasenor and Graham 2010; Kurugol and Gulec 2012), but when they are found in 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 esatto the scale of the site and its territory or expand preciso long-scale range imports and cross other issues such as those concerning the methods and extent of the commercializzazione of raw materials in per given period (e.g. “what was the diffusion of these materials?”; “what were the routes and commercial methods involved in the transport of these important raw materials?”).