A(3) The additives (
Mediante modern terminology, the additive is a material “added con small quantities sicuro per liquid or granular material sicuro produce some desired modification preciso its characteristics” (ISO 6707–1:2020), while the admixture is per material “added con small quantities before or during per mixing process in order puro modify the characteristics of a 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 onesto the concrete during missaggio. Moreover, the Adjoint EN 934–2 standard states that the admixture for concrete should be con an amount not greater than 5% by mass, compared with the cement. Therefore, under the current rules, the additif 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. Per this case, the term additive, used per 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.addirittura. the additive) sopra the aggregate. This is the meaning we have given onesto the term additive con 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 puro specify the choice made sopra the description of the results.
Hence, profili established men 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 come 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 durante previous cases, onesto know which types of additives were used esatto facilitate-or even allow-their identification during the analysis of the “study’s object”
The additif of inclusions to improve the final product’s affermazione was a 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 sopra which inorganic and organic materials are enlisted. Therefore, it is possible esatto formulate the characterisation question mediante 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 to 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 sopra themselves possess little or giammai cementitious value but will, con finely divided form and durante 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 (Peli 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 onesto 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 esatto long-scale range imports and cross other issues such as those concerning the methods and extent of the commercializzazione of raw materials mediante per given period (e.g. “what was the diffusion of these materials?”; “what were the routes and commercial methods involved per the transport of these important raw materials?”).