A(3) The additives (
Durante modern terminology, the additive is verso material “added durante small quantities preciso verso liquid or granular material esatto produce some desired modification preciso its characteristics” (ISO 6707–1:2020), while the admixture is a material “added sopra small quantities before or during per mixing process sopra order onesto modify the characteristics of verso 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 mixing. Moreover, the Adjoint 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 prime of materials, such as ground ceramic fragments, con 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 esatto reconstruct the production’s phases and the supply modalities of each component. Durante this case, the term additive, used sopra 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.ancora. the additive) sopra the aggregate. This is the meaning we have given puro 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 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 tipo di from or how were they made?” (other questions concern suitability and functionality and are reported sopra the dedicated paragraphs).
Esatto properly solve this question, it is necessary, perhaps even more than durante previous cases, to know which types of additives were used preciso facilitate-or even allow-their identification during the analysis of the “study’s object”
The addition of inclusions esatto improve the final product’s successo was verso common practice that frequently left recognisable traces in 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 onesto formulate the characterisation question per terms of: “are the additives of an inorganic or organic nature?” (we will see later that there are additional difficulties mediante 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 in nessun caso cementitious value but will, in finely divided form and durante 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 per the mortars/plasters of sites located within or close preciso volcanic regions (Barba 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 https://datingranking.net/it/fitness-singles-review/ question may thus remain confined esatto 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 commercializzazione of raw materials mediante verso given period (addirittura.g. “what was the diffusion of these materials?”; “what were the routes and commercial methods involved mediante the transport of these important raw materials?”).