A(3) The additives (
Per modern terminology, the additive is a material “added per small quantities to verso liquid or granular material onesto produce some desired modification to its characteristics” (ISO 6707–1:2020), while the admixture is per material “added mediante small quantities before or during per mixing process mediante order esatto modify the characteristics of per mixture”. However, the difference between the two terms lies mainly sopra that the additive is added during the manufacturing of the cement, while the admixture is added sicuro the concrete during mixing. Moreover, the Accouple EN 934–2 norma states that the admixture for concrete should be in an amount not greater than 5% by mass, compared with the cement. Therefore, under the current rules, the addenda 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 onesto reconstruct the production’s phases and the supply modalities of each component. Durante this case, the term additive, used mediante its etymological sense (from addere, puro add) has the advantage of clearly recalling the difference between per primary component (frequently sand) and an added component (i.e. the additive) sopra the aggregate. This is the meaning we have given esatto 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 Esempi di profilo fcn chat different needs. It follows that, as long as terminological uncertainties persist, it is always good puro specify the choice made mediante 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 come from or how were they made?” (other questions concern suitability and functionality and are reported con the dedicated paragraphs).
Preciso properly solve this question, it is necessary, perhaps even more than in previous cases, esatto know which types of additives were used sicuro facilitate-or even allow-their identification during the analysis of the “study’s object”
The addition of inclusions esatto improve the final product’s esibizione was a common practice that frequently left recognisable traces durante 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 sicuro 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 sopra this second case).
For this reason, we present per 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 no cementitious value but will, sopra finely divided form and mediante 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 mediante the mortars/plasters of sites located within or close preciso volcanic regions (Peli et al. 2009; Ozkaya and Boke 2009; Villasenor and Graham 2010; Kurugol and Gulec 2012), but when they are found sopra sites far from supply areas, archaeometric research is called upon to 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 ciclocross 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 durante the transport of these important raw materials?”).
