ANCIENT ROMAN MORTARS: MIX DESIGN, MINERALOGICAL COMPOSITION AND MINEROGENETIC SECONDARY PROCESSES

Aim of this study is the characterization of ancient Roman mortars collected in a) Piscina Mirabilis, b) Terme di Baia, c) Villa del Capo (commonly called Bagni della Regina Giovanna) and d) Villa del Pezzolo sites. All investigated location are placed in two important geological, archaeological and historical areas of Campania Region: Campi Flegrei and Sorrento Peninsula. Goals of this research project were: a) to improve the knowledge of Roman construction techniques by means of detailed microstructural and compositional examination of 1) cementitious binding matrix and 2) aggregates, to point out both mortars’ mix-design and provenance of raw materials, along with b) the study of secondary minerogenetic processes and c) comparing the obtained results with the modern mortars. Thanks to the permission by Superintendence of Archeological Heritage of Campania, it was possible to take out small, non-invasive, and representative samples of mortars. The collected samples were used for an integrated analytical program using multiple methodologies such as: optical microscopy (OM) on thin sections, X-ray powder diffraction (XRPD), scanning electron microscopy analysis (SEM), energy-dispersion X-ray spectroscopy (EDS), X-ray fluorescence (XRF), thermal analyses (TGA-DTA) and mercury intrusion porosimetry (MIP). This research activity was performed in collaboration with CTG (Group Technical Center) of Italcementi Hidelberg Group at Bergamo (Italy). Results have shown that building materials used in studied archaeological sites had a local provenance, and are very well consistent with the surrounding geological setting. A relevant characteristic detected in all samples is the evident hydraulicity of these mortars, as shown by the reaction rims of pozzolanic materials; this feature is supported by the Hydraulicity Index and thermal analyses investigations. Extremely interesting is composition of cementitious binding matrix characterized by various products of reaction, including amorphous gel-C-A-S-H, calcite, tobermorite (Piscina Mirabilis samples) and hydrocalumite (Villa del Capo samples). In particular, these two late secondary minerogenetic products refine fill pore space and thus enhancing bonding in pumice clasts. The difference between ancient Roman mortars and modern hydraulic mortar was mainly related to porosity

New Insights of Historical Mortars Beyond Pompei: The Example of Villa del Pezzolo, Sorrento Peninsula

The topic of this study is the archaeometric characterization of mortars from Villa del Pezzolo, a Roman Villa located in Seiano (Napoli-Campania, Italy), dated between the 1st century B.C. and the 3rd century A.D. Mortars were analyzed by means of a multi-analytical approach (polarized optical microscopy, X-ray powder diffraction, scanning electron microscopy and energy-dispersed spectrometry, thermal analyses and mercury intrusion porosimetry) according to existing recommendations. Analytical results evidenced the use of local geomaterials composed of sedimentary and volcanic aggregates in the mix design and confirmed the three distinct building phases identified by archaeologists. Volcanic tuff fragments, identified in the 1st building phase can be ascribed to Campanian Ignimbrite formation, widely cropping out in the Sorrento Peninsula, as confirmed by the presence of glassy shards, partially devitrified and replaced by authigenic feldspar, a typical feature of welded grey ignimbrite lithofacies (WGI). Volcanic aggregates in samples of the 2nd and 3rd building phases show, instead, the presence of leucite-bearing volcanic scoriae and garnet crystal fragments related to Somma-Vesuvius products. Study of these mortars allowed us to: (1) understand the production technologies; (2) highlight use of materials with hydraulic behavior, such as volcanic and fictile fragments; (3) confirm the three building phases from compositional features of mortars and (4) highlight the change over time of the volcanic aggregate for mortars mix-design

New Insights of Historical Mortars Beyond Pompei: The Example of Villa del Pezzolo, Sorrento Peninsula

The topic of this study is the archaeometric characterization of mortars from Villa del Pezzolo, a Roman Villa located in Seiano (Napoli-Campania, Italy), dated between the 1st century B.C. and the 3rd century A.D. Mortars were analyzed by means of a multi-analytical approach (polarized optical microscopy, X-ray powder diffraction, scanning electron microscopy and energy-dispersed spectrometry, thermal analyses and mercury intrusion porosimetry) according to existing recommendations. Analytical results evidenced the use of local geomaterials composed of sedimentary and volcanic aggregates in the mix design and confirmed the three distinct building phases identified by archaeologists. Volcanic tuff fragments, identified in the 1st building phase can be ascribed to Campanian Ignimbrite formation, widely cropping out in the Sorrento Peninsula, as confirmed by the presence of glassy shards, partially devitrified and replaced by authigenic feldspar, a typical feature of welded grey ignimbrite lithofacies (WGI). Volcanic aggregates in samples of the 2nd and 3rd building phases show, instead, the presence of leucite-bearing volcanic scoriae and garnet crystal fragments related to Somma-Vesuvius products. Study of these mortars allowed us to: (1) understand the production technologies; (2) highlight use of materials with hydraulic behavior, such as volcanic and fictile fragments; (3) confirm the three building phases from compositional features of mortars and (4) highlight the change over time of the volcanic aggregate for mortars mix-design

Ancient Roman Mortars from Villa del Capo di Sorrento: A Multi-Analytical Approach to Define Microstructural and Compositional Features

This research provides a characterization of ancient Roman mortars from “Villa del Capo di Sorrento” (commonly known as “Villa di Pollio Felice” or “Bagni della Regina Giovanna”). A deepened analysis of cementitious binding matrix and aggregates was conducted with the aims of determining possible sources of raw materials and the mix recipe, and to evaluate the minerogenetic secondary processes. Twenty samples taken from the Villa were investigated by means of a multi-analytical approach, including polarized optical microscopy on thin sections, X-ray powder diffraction, scanning electron microscopy analysis, energy dispersed spectrometry, simultaneous thermal analyses, and mercury intrusion porosimetry. Bedding mortars were made with slaked lime mixed with volcanic materials, whereas coating mortars were made adding to previous recipe as ceramic fragments. All samples were classified as hydraulic mortars. Cementitious binding matrix was characterized by gel-like C-A-S-H, calcite, hydrocalumite, and gypsum, deriving from lime/pozzolanic material. Geomaterials used for mortar production had a local origin. Pozzolanic materials, such as volcanic fragments, scoriae, pumice, and crystal fragments derived from both pyroclastic rocks of the Campi Flegrei district and from rocks of the Somma-Vesuvio complex; porosity test suggest that the products related to minerogenetic secondary processes, make mortars more resistant

Lime and Cement Plasters from 20th Century Buildings: Raw Materials and Relations between Mineralogical–Petrographic Characteristics and Chemical–Physical Compatibility with the Limestone Substrate

This paper deals with the “modern” plaster mortars based on air lime, hydraulic lime, and cement used between the 1950s and 1990s of the last century, taking, as a case study, a historical building of the Cagliari city whose foundations and ground floor are cut into in-situ limestone. Different plaster layers (i.e., arriccio and intonachino, paint), applied on the excavated limestone walls, were collected from cave-room. All samples were analysed by optical and electron (SEM-EDS) microscopy and X-ray diffractometry (XRD) in order to define their microstructures, textures and compositional features. In addition, real and bulk density, water and helium open porosity, water absorption kinetic, and saturation index were measured. By microscopic imaging analyses, the binder/aggregate ratio as vol.% was determined. Results revealed that cement mortars, composed mainly of C-S-H, C-A-H, and C-F-H phases, given their high hydraulicity, low open porosity, and a rigid behaviour, showed a good chemical but not physical–mechanical adherence, as they were often found detached from the substrate and frequently loaded with salt efflorescence. On the contrary, the hydraulic lime-based mortars, characterised by a binder composed of C-S-H and C-A-H phases and calcite derived from the portlandite carbonation, showed a greater affinity with limestone substrate and other plasters. Thus, they are more suitable to be used as a repair mortar, showing a long durability on the time. The thin air lime-based plasters (intonachino) showed a good adhesion to the substrate, exerting their coating function better than the harder, cement-based mortars. Lime-based wall paints have a good chemical adhesion and adaptability to the irregular surface of the substrate, due to low thickness of lime paint layers (<1 mm) that confers an elastic physical behaviour

Nodules and chert layers in the Ichtyolitic Limestones Formation of Civita of Pietraroja (Southern Apennines, Italy). A genetical model

The present paper concerns the study of the silicization&nbsp;processes occurring in the “Ichthyolitic Limestone”&nbsp;outcropping at the Civita of Pietraroja (Benevento), in the&nbsp;Matese Mountains. (Southern Apennines, Italy). PreviousAuthors provided descriptions of these deposits, without&nbsp;proposing a specific genetic model. Different types of cherts&nbsp;were observed, sampled, and studied in optical microsocopy,&nbsp;characterizing their sedimentological features, the containedmicrofauna, and their state of conservation. Observations&nbsp;confirm that silicization is penecontemporary to the&nbsp;sedimentation of the fine-grained lagoonal limestones.&nbsp;Specifically, to explain silicization processes in limestones, thefollowing paleo-environmental context of the Pietraroja&nbsp;lagoon, and the surrounding areas, must be taken into&nbsp;account: a first source of primary silica may have been located&nbsp;in the emerged areas overlooking the lagoon, wherecarbonate weathering processes, leading to the formation of&nbsp;bauxites, had probably begun. This leaded to the accumulation&nbsp;of residual materials (including siliceous ones). The “Orbitolina&nbsp;Level of the Campania” too, derived at least in part from the&nbsp;accumulation of pyroclastic materials, slightly older than the&nbsp;"Ichthyolitic Limestones" and cropping out in the area in the&nbsp;uppermost Aptian-lower Albian, could be regarded as an&nbsp;additional source of primary silica. The richness in silica of this&nbsp;neritic-lagoon environment could consistently have supported&nbsp;the development of siliceous sponge colonies, whose spicules, originally consisting of Opal A,&nbsp;are often very abundant in lagoonal sediments. According to the described conditions, a&nbsp;mixing zone between fresh meteoric and continental waters and lagoonal marine waters, was&nbsp;very likely present in the sediments bordering the lagoon and within it. In accordance with a&nbsp;previously proposed model, the dissolution of sponge spicules (Opal A, biogenic silica), and&nbsp;the reprecipitation of silica phases as colloidal gels within the carbonatic sediments could give&nbsp;rise to silicizations in the form of nodules and layers.Il lavoro prende in considerazione le silicizzazioni presenti nei “Calcari ad Ittioliti” affioranti alla&nbsp;Civita di Pietraroja (Benevento), nel Matese orientale (Appennino Meridionale, Italia).&nbsp;Precedenti Autori ne hanno fornito descrizioni, senza però proporre uno specifico modello&nbsp;genetico. Le diverse tipologie di selce osservate sono state campionate e studiate in sezione&nbsp;sottile, caratterizzandone le litologie sedimentarie, le microfaune e le loro condizioni di&nbsp;conservazione. Le osservazioni conferm&nbsp;individuate come fonti primarie di silice le aree emerse prospicienti dove, con ogni probabilità,&nbsp;erano iniziati i processi di “weathering” dei carbonati che condurranno alla formazione di&nbsp;bauxiti, con accumulo di materiali residuali, tra cui quelli silicei. Il “Livello a Orbitoline della&nbsp;Campania”, in parte a matrice piroclastica, poco più antico dei Calcari ad Ittioliti, ed&nbsp;evidentemente affiorante o subaffiorante nell’area nell’Aptiano terminale - Albiano basale,poteva costituire una ulteriore fonte di silice primaria nei terreni a contorno della laguna. La&nbsp;ricchezza in silice di tale ambiente neritico-lagunare poteva pertanto favorire lo sviluppo di&nbsp;colonie di spugne silicee, le cui spicole, originariamente costituite da opale A, sono&nbsp;abbondantissime nei sedimenti lagunari dei Calcari ad Ittioliti di Pietraroia.&nbsp;Nelle condizioni descritte, una zona di mixing tra acque dolci meteoriche e continentali e&nbsp;acque marine lagunari, era certamente presente nei sedimenti a contorno della laguna e nella&nbsp;laguna stessa. In essa potevano avvenire i processi di soluzione della silice biogenica (opale-A)&nbsp;derivata dalle spicole di spugne e la riprecipitazione di essa in forma di gel colloidali nei&nbsp;sedimenti carbonatici, formando noduli e letti di selce sui fondali lagunari

Ancient Roman Mortars from Villa del Capo di Sorrento: A Multi-Analytical Approach to Define Microstructural and Compositional Features

This research provides a characterization of ancient Roman mortars from “Villa del Capo diSorrento” (commonly known as “Villa di Pollio Felice” or “Bagni della Regina Giovanna”). A deepenedanalysis of cementitious binding matrix and aggregates was conducted with the aims of determiningpossible sources of raw materials and the mix recipe, and to evaluate the minerogenetic secondaryprocesses. Twenty samples taken from theVillawere investigated by means of a multi-analyticalapproach, including polarized optical microscopy on thin sections, X-ray powder diffraction, scanningelectron microscopy analysis, energy dispersed spectrometry, simultaneous thermal analyses, andmercury intrusion porosimetry. Bedding mortars were made with slaked lime mixed with volcanicmaterials, whereas coating mortars were made adding to previous recipe as ceramic fragments.All samples were classified as hydraulic mortars. Cementitious binding matrix was characterizedby gel-like C-A-S-H, calcite, hydrocalumite, and gypsum, deriving from lime/pozzolanic material.Geomaterials used for mortar production had a local origin. Pozzolanic materials, such as volcanicfragments, scoriae, pumice, and crystal fragments derived from both pyroclastic rocks of theCampiFlegreidistrict and from rocks of theSomma-Vesuviocomplex; porosity test suggest that the productsrelated to minerogenetic secondary processes, make mortars more resistant

Mineralogical and Technological Characterization of Zeolites from Basin and Range as Pozzolanic Addition of Cement

The present paper assesses petrographic, mineralogical, chemical, and technological features of different zeolitic tuff samples from various western USA districts of the Basin and Range Province containing mainly erionite, mordenite, clinoptilolite/heulandite and phillipsite. The aim of this characterization is to evaluate the pozzolanic activity of these samples according to European normative UNI-EN 196/5 (Fratini test) to program a possible use as addition for blended cements. Petrographic and mineralogical results show that the two phillipsite-bearing tuffs have a higher theoretical Cation Exchange Capacity (CEC) than the other samples; technological characterization shows a pozzolanic behavior for all the samples but higher for the tuff samples containing phillipsite, which shows a higher reactivity with CaO. All the samples could be thus advantageously employed for the preparation of blended cements, potentially reducing CO2 emissions by 70&ndash;90%

Contribution to the knowledge of ancient Roman seawater concretes:Phlegrean pozzolan adopted in the construction of the harbourat Soli-Pompeiopolis (Mersin, Turkey)

This study deals with the characterization of ancient seawater concretes from the Roman harbour of Soli-Pompeiopolis, 1st century B.C., at Mersin in Turkey, drilled by the ROMACONS (Roman Maritime Concrete Study) team in 2009. This research activity was performed in collaboration with the Laboratories Department of CTG Italcementi Group and the Earth Sciences Department of the University "Federico II" of Naples. Results confirmed that the Roman engineers extensively used coarse tuff aggregate, lime hydrated in seawater, and pozzolanic volcanic fine sand, the so-called pulvis puteolanus of Vitruvius's treatise De Architectura (1st century B.C.). The typical mineralogical association of phillipsite > chabazite > analcime, in particular points out the provenance for the tuff aggregate from the Yellow Neapolitan Tuff (NYT) formation, which is connected to the Campi Flegrei volcanic activity, dated back to 15.000 years ago. As far as the fine pozzolanic sand, of which just some scoria relics have been observed, can be ascribed to the same formation, or, probably, to the pozzolan stricto sensu pyroclastic flow from the Campi Flegrei area, as well. EDS microanalyses of different phillipsite crystals showed that the content of major alkaline and alkaline-earth metals was very close to those of phillipsite crystals from NYT, with K higher than Na and Ca, as previously reported in the literature. This fact clearly attests that zeolites were not involved in cation exchange processes within the seawater, despite of their long time curing approximately two thousand years - in the marine environment