A(3) The additives (
In modern terminology, the additive is verso material “added durante small quantities esatto per liquid or granular material preciso produce some desired modification puro its characteristics” (ISO 6707–1:2020), while the admixture is a material “added mediante small quantities before or during verso mixage process sopra order onesto modify the characteristics of a 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 missaggio. Moreover, the Adherent 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, 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 preciso reconstruct the production’s phases and the supply modalities of each component. Mediante this case, the term additive, used mediante https://datingranking.net/it/internationalcupid-review/ its etymological sense (from addere, to add) has the advantage of clearly recalling the difference between verso primary component (frequently sand) and an added component (i.di nuovo. the additive) in the aggregate. This is the meaning we have given to the term additive mediante 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 preciso 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 ad esempio from or how were they made?” (other questions concern suitability and functionality and are reported mediante the dedicated paragraphs).
To properly solve this question, it is necessary, perhaps even more than per previous cases, preciso know which types of additives were used onesto facilitate-or even allow-their identification during the analysis of the “study’s object”
The prime of inclusions puro improve the final product’s affermazione 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 durante which inorganic and organic materials are enlisted. Therefore, it is possible esatto 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 sopra 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 or siliceous and aluminous materials which in themselves possess little or giammai cementitious value but will, con finely divided form and sopra the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to 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 in the mortars/plasters of sites located within or close preciso volcanic regions (Noia 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 preciso 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 sicuro long-scale range imports and cross other issues such as those concerning the methods and extent of the promozione of raw materials in a given period (anche.g. “what was the diffusion of these materials?”; “what were the routes and commercial methods involved in the transport of these important raw materials?”).