This research aims to deepen knowledge on geomaterials used in building operations of a very impo... more This research aims to deepen knowledge on geomaterials used in building operations of a very important monumental complex belonging to the "Porta Mediana" necropolis the archeological site of Cuma. The entire site counts 70 mausoleums among which, the one named "Sphinx complex" or A63, is particularly important. For its realization several geomaterials have been used. Analytical results were carried out from several techniques such as optical microscopy, microchemical and mineralogical-petrographical analysis, scanning electron microscopy with EDS and X-ray powder diffraction. This approach allows to clarify the provenance of natural geomaterials and also the technological processes involved in the production of artificial geomaterials (mortars, plasters, cocciopesto). Phlegrean tuffs, due to their easy workability and good mechanical features, were used mainly for masonries and for decorative function (a bas-relief of a "sphinx" for example). As far as...
Wastes produced from geomaterials working processes represent a cost to dump and can have a remar... more Wastes produced from geomaterials working processes represent a cost to dump and can have a remarkable environmental impact. In this light it is clear the importance of scientific researches finalized to the reuse of this wastes as raw material for other industrial purposes. During this research, sawing and polishing wastes from granitic rocks and ceramics were considered. Dimension stones working processes generate muds amounts of 25% in weight of the raw material while the grès tiles ones about 50.000 metric tons/year only for Italy (ANPA, 2002). This muds reveal a low abrasive (SiC) and steel filings amount (1-2%), so CER 010410/13 and 10129 are the corresponding European codes for this kind of wastes. Nowadays only a small part of this muds are reused even if there is a lot of scientific literature about this matter. This research prove that ceramic muds chemical composition both with the presence of some SiC percentages cause the expansion of the material after thermical treatm...
A Roman luxury villa (1 century BC) was discovered in the town of Positano, in the Sorrento penin... more A Roman luxury villa (1 century BC) was discovered in the town of Positano, in the Sorrento peninsula (Campania region, southern Italy). Despite being more than 20 km away from Vesuvius, the villa was buried under almost overall 20 meters (total thickness) of pyclastic materials of the Plinian eruption of 79 AD, which destroyed Pompeii and Herculaneum towns. The exceptional level of conservation of this residential complex is due to the peculiar burial process, which determined the excellent state of preservation of both the fresco decorations (Fourth Style) and all other artefacts (masonries, plasters, tiles, furnishing remains, wooden elements, kitchenware, glazed oil lamps, bronze vessels and other metallic findings, etc.). This study presents the results of a multi-analytical archaeometric analysis of plasters, fresco pigments and roof tiles, aimed at identifying their mineralogical and petrographic nature and the provenance of raw materials. Constraints to the geoarchaeological...
Roman mortars from a mausoleum (named D46b) belonging to the archaeological site of Porta Mediana... more Roman mortars from a mausoleum (named D46b) belonging to the archaeological site of Porta Mediana necropolis, in Cuma (Naples, Southern Italy) have been studied by means of petrographic, mineralogical and micro-chemical analyses. The aim of this research is to fill the knowledge gap regarding mortar-based materials used in Roman age within this wide archaeological site. Two typologies of mortars (bedding and coating) were collected from mausoleum's masonry. They were lime-based with addition of pozzolanic materials, according to Vitruvius' recipe. Raw materials, such as volcanic sand and limestones, mainly from local sources, were preferentially used as aggregate, both for great availability and good properties. As regard production techniques, the multi-layer feature of the coating mortars, once again shows the great knowledge of the building art. Each layer is the result of a precise choice, as shown by the differences both in texture and petrographic features. Data from d...
This paper focuses on the authigenic mineralization processes acting on "Tufo Rosso a Scorie... more This paper focuses on the authigenic mineralization processes acting on "Tufo Rosso a Scorie Nere" (TRS), i.e. one of the main pyroclastic units of the Vico stratovolcano (Latium, Italy). The pyroclastic deposits appear in general massive and made of "black vitreous vesiculated juvenile scoriae", immersed in an ashy matrix lithified after zeolitization processes. The main minerals are chabazite and phillipsite, and the zeolitic content is locally variable, reaching 68 % wt. Zeolites grow replacing both amorphous fraction and pre-existing phases, occurring inside both matrix and scoriae. Concerning scoriae, zeolitization moves from the rim to the core of the scoriaceous fragment as a function of (a) temperature of the fluids and (b) permeability (primary or secondary). Composition of parental fresh glass and that of zeolitized rocks is compatible with trachyte chemistry, lightly undersaturated in SiO 2 , and the alteration processes modified the parental rock chem...
In soil stabilisation, the use of alternative products to lime or cement has been proposed. Howev... more In soil stabilisation, the use of alternative products to lime or cement has been proposed. However, the effects of these additives, of various origins, on soil behaviour and stabilizing mechanisms are not well understood. Thus, the aim of this paper is to characterize the modification of the mechanical behaviour and microstructure of two soils after treatment with one of those product, a vinyl based copolymer. After treatment, both materials were compacted up to their maximum dry density. The mechanical behaviour of the materials as a function of the curing conditions, suction and water content was first determined. In a second step, the alteration of the microstructure by the treatment product was assessed. The results showed that the treatment permitted to significantly improve the strength of the tested soils. Moreover, the efficiency of the product increases when the soil is dried. However, the Young modulus is not significantly modified by the treatment. Microstructural reorga...
Natural stones have represented one of the main building materials since ancient times. In recent... more Natural stones have represented one of the main building materials since ancient times. In recent decades, a worsening in degradation phenomena related mostly to environmental pollution was observed, threatening their conservation. The present work is focused on the minero-petrographic and geochemical characterization of black crust (BC) samples taken from the historical center of Naples, after selecting two pilot monumental areas. The latter were chosen based on their historical importance, type of material, state of preservation and position in the urban context (i.e., high vehicular traffic area, limited traffic area, industrial area, etc.). The building materials used and their interaction with environmental pollutions were studied comparing the results obtained by means of different analytical techniques such as polarized light Optical Microscopy (OM), scanning electron microscopy with energy dispersion system (SEM-EDS), X-ray powder diffraction (XRPD) and laser ablation couple...
Rendiconti Online della Società Geologica Italiana
This research is part of the PON (Programma Operativo Nazionale) SINAPSIS (SIstema NAzionale Prot... more This research is part of the PON (Programma Operativo Nazionale) SINAPSIS (SIstema NAzionale Protezione SIti Sensibili), an interdisciplinary project combining archaeological and archaeometric methods. This paper focuses on frescoes from one of the 70 funeral monuments belonging to "Porta Mediana" Necropolis, a very interesting archaeological context located in Cuma, dating back to the first half of the 3rd century BCE. The study provided detailed information on pigments and colors acquired both on untreated and treated (restored) frescoes. Portable colorimetry and chemical-mineralogical (Raman spectroscopy and X-ray powder diffraction-XRPD, respectively) analyses were performed in situ and on collected samples in order to: 1) identify pigments, raw materials and provenance, 2) point out possiblecolor changes caused by conservative treatments and/or weathering. The identified palette is typical of the Roman period; it includes both single and mixtures of two or more pigments to obtain particular hues. Moreover, the identified raw materials, such as red and yellow ochres, green frit and Egyptian blue, clearly highlighted the choice to use raw materials from local sources. The use of expensive coloring materials also suggests that the mausoleum belonged to a family or a group of people with a high social status.
Aim of this study is the characterisation of ancient Roman mortars collected in Piscina Mirabilis... more Aim of this study is the characterisation of ancient Roman mortars collected in Piscina Mirabilis, located in the important geological, archaeological and historical area of the Campania Region (southern Italy): the Campi Flegrei. Goals of this research were (a) improving knowledge of Roman construction techniques by means of detailed microstructural and compositional examination of cementitious binding matrix and aggregates, to point out both mortar mix-design and provenance of raw materials, (b) the study of secondary minerogenetic processes and (c) comparison with modern mortars. Thanks to the permission by the former Soprintendenza Archeologia della Campania (authority of the archaeological heritage) current “Parco Archeologico dei Campi Flegrei”, it was possible to collect small, non-invasive, but representative samples of mortars. Samples were studied by combined 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), simultaneous thermal analyses (STA) and mercury intrusion porosimetry (MIP). Results showed that local geomaterials were used in this archaeological site, as they are well consistent with the surrounding geological setting. A relevant characteristic is the hydraulicity of these mortars shown by the reaction rims of pozzolanic materials. Composition of the cementitious binding matrix is characterized by various products of reaction, including amorphous C-A-S-H gel, calcite and Al-tobermorite. Results also highlighted that porosity represents the main difference between ancient Roman mortars and modern hydraulic ones.
The topic of this study is the archaeometric characterization of mortars from Villa del Pezzolo, ... more 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 ignim...
Abstract The Neapolitan Yellow Tuff (hereafter NYT) is definitely the building material most used... more Abstract The Neapolitan Yellow Tuff (hereafter NYT) is definitely the building material most used in the historical architecture of Naples (Southern Italy) since Greek times. The high heterogeneity of NYT, resulting from the concomitant occurrence of lithic fragments, pumices, crystals and glass cemented by crystalline or amorphous phases, the latter highly sensitive to acid environments, define a strong attitude to weathering. This research confirmed the inhomogeneous features of this volcanic formation, within the same deposit and sometimes within the same outcrop. Based on these premises, the investigation was carried out on four most representative lithofacies, according to their different textural and petrophysical features. Actually, mechanical features are governed by two concurring factors: a) the mineralogical composition; b) the texture of the rock. In the first case, the predominance of anhydrous phases (analcime + feldspar) over zeolites improves its mechanical strength. By contrast, if the mineralogical composition is constant (similar total wt.% zeolite content), the petrophysical parameters are strictly related to the texture of the rock.
ABSTRACT Industrial minerals represent an important resource for the Italian economy, both in ter... more ABSTRACT Industrial minerals represent an important resource for the Italian economy, both in terms of exploitation and transformation, especially in those sectors for which Italy holds a leadership such as ceramics and glass. Among Italian regions Campania is one of the poorest of such kind of resources although some geological formations could be advantageously exploited. An important role is played by the deposits of sedimentary zeolites linked to the activity of different volcanic districts occurring on the Neapolitan territory such as the Campanian Ignimbrite, the most important volcanic episode of the Campi Flegrei (Southern Italy), which blankets a wide area of the Campanian region. The Campanian Ignimbrite has been thoroughly investigated from a volcanological and petrographic point of view. However, little attention was devoted to the attainment of those information useful to verify the potential of the deposit as well as the interpretation of post-depositional mineral-forming processes that have affected this deposit and have led to the formation of several facies, among which the most important are characterized by intense feldspathization (grey facies) and remarkable zeolitization (yellow facies). X-ray diffraction, X-ray fluorescence, inductively coupled plasma emission spectrometry and scanning electron microscopy methods were used to thoroughly characterize the entire set of samples collected from 31 outcrops. Data so far acquired enabled to define the role played by several parameters (i.e., temperature, alkaline and alkaline-earth cations, etc.) in influencing the zeolitization process and the consequent crystallization of phillipsite, chabazite, and analcime. Feldspathization appears to have been controlled mainly by the emplacement temperature of the deposits. The proposed genetic model involves emplacement of the pyroclastic flow in a single episode, producing a deposit with an upward-decreasing temperature gradient. In this model, the central portion had a temperature insufficient to cause significant feldspathization, and the upper portion of the formation was affected by water percolation while still hot, producing progressive zeolitization. Volcano-stratigraphical parameters suggest some constrains on the maximum temperatures affecting the central portion of WGI. Thermodynamic data on zeolites constrain the maximum temperatures of the LYT unit which likely decrease upwards in the unit up to ambient conditions in CPF.
Abstract There is a growing concern on lightweight aggregates (LWA) for recycling of waste materi... more Abstract There is a growing concern on lightweight aggregates (LWA) for recycling of waste materials: this manufacturing technology is considered a flexible tool to make it possible the conversion of large amounts of residues into building products. The main challenge for this purpose is the control on the technological behavior during firing of waste-bearing batches. The target is engineering the sintering and expansion of LWA in order to tailor bulk density, mechanical strength and water absorption on various possible applications (e.g., structural and non-structural lightweight concretes, lightweight mortars, filtration substrates, floriculture). The prediction of the aggregate expansion – and hence the batch design – is usually carried out utilizing the Riley’s and/or Cougny’s schemes, which are based on the bulk chemical composition of clay bodies. However, collecting the literature data on waste-based LWA and plotting them in the Riley’s and Cougny’s diagrams, no reliable discrimination turns out between expanding and non-expanding batches. In the same way, the attempt to modify the Riley’s and Cougny’s parameters, including elements present in wastes but not in natural raw materials, was unsuccessful. From this standpoint, a new approach to assess the batch expandability was developed through a deeper comprehension of mechanisms acting on sintering and expansion of LWA. A specific characterization protocol was set up, entailing hot-stage microscopy and determination of phase composition and microstructure. This implies a paradigm shift from batch (chemical composition) to vitreous phase (amount, chemical composition, and viscosity at high temperature). The vitreous phase plays a key-role for bloating, microstructure and physical properties of LWA. A working example is presented about new LWA based on waste glasses, ceramic tile polishing sludge and clay raw materials.
Aim of this research is an evaluation of the zeolitized facies of Campanian Ignimbrite as raw mat... more Aim of this research is an evaluation of the zeolitized facies of Campanian Ignimbrite as raw material for the production of lightweight expanded aggregates (LEA). A commercial product (Cab70) was used as reference for this rock. Tests were carried out on "pure" samples or mixed with an industrial waste mud (DPM -Dried Polishing Mud) deriving from a porcelain stoneware tile polishing process. This mud contains SiC, a phase known to act as bloating enhancer. Raw materials were subjected to mineralogical (XRPD-RIR method) and chemical (XRF) analyses. Bloating upon heating was measured (Leitz heating microscope) on Cab70, DPM and on three mixtures having the following Cab70/DPM ratios: 85/15 (Mix1); 70/30 (Mix2); 50/50 (Mix3). LEA production was assessed both in static (muffle kiln) and in dynamic (rotating kiln) conditions by firing pellets, 3-8 mm in size, between 1220-1380°C. The unit weight of the single particle was determined on fired and unfired products. All materials evidenced a decreasing density with temperature whereas the same parameter decreases with DPM increasing content. Cab70 LEAs never dropped below 0.90 g/cm 3 , even at the highest temperature, whereas DPM LEAs range between 0.86 g/cm 3 (at 1260°C) and 0.46 g/cm 3 (at 1380°C). A direct but not linear relationship between DPM content and density was evidenced. Among the three mixtures, Mix2 showed the lowest DPM content able to produce the strongest density reduction. To get LEAs with the same density the rotating kiln required temperatures generally 60-80°C higher than those of the muffle kiln. This difference should be related to the different thermal insulation of the two systems during firing. Two sets of LEAs were massively produced in dynamic conditions from Cab70 (at 1380°C) and Mix2 (at 1300°C). These latter showed better technical performances in terms of unit weight of the single particle (0.81 vs. 0.98 g/cm 3 ), bulk unit weight (460 vs. 565 kg/m 3 ), water absorption coefficients (1.4 vs. 5.5% after 24 h) and compressive strength of the particles (2.9 vs. 0.6 MPa). Differences in pore shape, dimension, abundance and spatial distribution were observed by SEM between the two sets. The technical features of these LEAs were comparable to some expanded clays, with similar grain size, commercialised in Italy.
This research provides possible opportunities in the reuse of waste and particularly muds, coming... more This research provides possible opportunities in the reuse of waste and particularly muds, coming from both ornamental stone (granite sludges from sawing and polishing operations) and ceramic production (porcelain stoneware tile polishing sludge), for the manufacture of lightweight aggregates. Wastes were characterized from the mineralogical (XRPD, X-Ray Powder Diffraction), chemical (XRF, X-Ray Fluorescence), and technological (HSM, Hot-Stage Microscopy) points of view, in order to assess their potential as bloating materials, and suitable mixes were designed. Lab simulation of the manufacturing cycle was performed by pelletizing and firing the waste mixes in a rotative furnace up to 1300 °C, and determining composition and physico-mechanical properties of lightweight aggregates. The best formulation was used to produce and test lightweight structural concretes according to standard procedures. Both granite and porcelain stoneware polishing sludges exhibit a suitable firing behaviour due to the occurrence of SiC (an abrasive component) which, decomposing at high temperature with gas release, acts as bloating promoter, resulting in aggregates with particle density <1 Mg/m 3 . However, slight variations of mixture composition produce aggregates with rather different properties, going from values close to those of typical commercial expanded clays (particle density 0.68 Mg/m 3 ; strength of particle 1.2 MPa) to products with high mechanical features (particle density 1.25 Mg/m 3 ; strength of particle 6.9 MPa). The best formulation (50 wt.% porcelain stoneware polishing sludge + 50 wt.% granite sawing sludge) was used to successfully manufacture lightweight structural concretes with suitable properties (Compressive strength 28 days > 20 MPa, bulk density 1.4-2.0 Mg/m 3 ).
expanded aggregates (LEA).Acommercial product (Cab70)was used as reference for this rock. Tests w... more expanded aggregates (LEA).Acommercial product (Cab70)was used as reference for this rock. Tests were carried out on “pure” samples or mixed with an industrial waste mud (DPM—Dried Polishing Mud) deriving from a porcelain stoneware tile polishing process. This mud contains SiC, a phase known to act as bloating enhancer. Rawmaterials were subjected ineralogical (XRPD–RIR method) and chemical (XRF) analyses. Bloating upon heating was measured (Leitz heating microscope) on Cab70, DPM and on three mixtures having the following Cab70/DPMratios: 85/15 (Mix1); 70/30 (Mix2); 50/50 (Mix3). LEAproductionwas assessed both in static (muffle kiln) and in dynamic (rotating kiln) conditions by firing pellets, 3–8 mm in size, between 1220–1380 °C. The unit weight of the single particle was determined on fired and unfired products. All materials evidenced a decreasing density with temperature whereas the same parameter decreases with DPM increasing content. Cab70 LEAs never dropped below 0.90 g/cm3, even at the highest temperature, whereas DPM LEAs range between 0.86 g/cm3 (at 1260 °C) and 0.46 g/cm3 (at 1380 °C). A direct but not linear relationship between DPMcontent and density was evidenced.Among the three mixtures,Mix2 showed the lowest DPMcontent able to produce the strongest density reduction. To get LEAs with the same density the rotating kiln required temperatures generally 60–80 °C higher than those of the muffle kiln. This difference should be related to the different thermal insulation of the two systems during firing. Two sets of LEAs were massively produced in dynamic conditions from Cab70 (at 1380 °C) and Mix2 (at 1300 °C). These latter showed better technical performances in terms of unit weight of the single particle (0.81 vs. 0.98 g/cm3), bulk unit weight (460 vs. 565 kg/m3), water absorption coefficients (1.4 vs. 5.5% after 24 h) and compressive strength of the particles (2.9 vs. 0.6 MPa). Differences in pore shape, dimension, abundance and spatial distribution were observed by SEMbetween the two sets. The technical features of these LEAs were comparable to some expanded clays, with similar grain size, commercialised in Italy. These results are worth interesting as they reveal new perspectives of application both for a rock characterized by a low exploitation cost and widely available in central-southern Italy, as well as for an industrial waste produced in high amount but not recycled at all.
This research aims to deepen knowledge on geomaterials used in building operations of a very impo... more This research aims to deepen knowledge on geomaterials used in building operations of a very important monumental complex belonging to the "Porta Mediana" necropolis the archeological site of Cuma. The entire site counts 70 mausoleums among which, the one named "Sphinx complex" or A63, is particularly important. For its realization several geomaterials have been used. Analytical results were carried out from several techniques such as optical microscopy, microchemical and mineralogical-petrographical analysis, scanning electron microscopy with EDS and X-ray powder diffraction. This approach allows to clarify the provenance of natural geomaterials and also the technological processes involved in the production of artificial geomaterials (mortars, plasters, cocciopesto). Phlegrean tuffs, due to their easy workability and good mechanical features, were used mainly for masonries and for decorative function (a bas-relief of a "sphinx" for example). As far as...
Wastes produced from geomaterials working processes represent a cost to dump and can have a remar... more Wastes produced from geomaterials working processes represent a cost to dump and can have a remarkable environmental impact. In this light it is clear the importance of scientific researches finalized to the reuse of this wastes as raw material for other industrial purposes. During this research, sawing and polishing wastes from granitic rocks and ceramics were considered. Dimension stones working processes generate muds amounts of 25% in weight of the raw material while the grès tiles ones about 50.000 metric tons/year only for Italy (ANPA, 2002). This muds reveal a low abrasive (SiC) and steel filings amount (1-2%), so CER 010410/13 and 10129 are the corresponding European codes for this kind of wastes. Nowadays only a small part of this muds are reused even if there is a lot of scientific literature about this matter. This research prove that ceramic muds chemical composition both with the presence of some SiC percentages cause the expansion of the material after thermical treatm...
A Roman luxury villa (1 century BC) was discovered in the town of Positano, in the Sorrento penin... more A Roman luxury villa (1 century BC) was discovered in the town of Positano, in the Sorrento peninsula (Campania region, southern Italy). Despite being more than 20 km away from Vesuvius, the villa was buried under almost overall 20 meters (total thickness) of pyclastic materials of the Plinian eruption of 79 AD, which destroyed Pompeii and Herculaneum towns. The exceptional level of conservation of this residential complex is due to the peculiar burial process, which determined the excellent state of preservation of both the fresco decorations (Fourth Style) and all other artefacts (masonries, plasters, tiles, furnishing remains, wooden elements, kitchenware, glazed oil lamps, bronze vessels and other metallic findings, etc.). This study presents the results of a multi-analytical archaeometric analysis of plasters, fresco pigments and roof tiles, aimed at identifying their mineralogical and petrographic nature and the provenance of raw materials. Constraints to the geoarchaeological...
Roman mortars from a mausoleum (named D46b) belonging to the archaeological site of Porta Mediana... more Roman mortars from a mausoleum (named D46b) belonging to the archaeological site of Porta Mediana necropolis, in Cuma (Naples, Southern Italy) have been studied by means of petrographic, mineralogical and micro-chemical analyses. The aim of this research is to fill the knowledge gap regarding mortar-based materials used in Roman age within this wide archaeological site. Two typologies of mortars (bedding and coating) were collected from mausoleum's masonry. They were lime-based with addition of pozzolanic materials, according to Vitruvius' recipe. Raw materials, such as volcanic sand and limestones, mainly from local sources, were preferentially used as aggregate, both for great availability and good properties. As regard production techniques, the multi-layer feature of the coating mortars, once again shows the great knowledge of the building art. Each layer is the result of a precise choice, as shown by the differences both in texture and petrographic features. Data from d...
This paper focuses on the authigenic mineralization processes acting on "Tufo Rosso a Scorie... more This paper focuses on the authigenic mineralization processes acting on "Tufo Rosso a Scorie Nere" (TRS), i.e. one of the main pyroclastic units of the Vico stratovolcano (Latium, Italy). The pyroclastic deposits appear in general massive and made of "black vitreous vesiculated juvenile scoriae", immersed in an ashy matrix lithified after zeolitization processes. The main minerals are chabazite and phillipsite, and the zeolitic content is locally variable, reaching 68 % wt. Zeolites grow replacing both amorphous fraction and pre-existing phases, occurring inside both matrix and scoriae. Concerning scoriae, zeolitization moves from the rim to the core of the scoriaceous fragment as a function of (a) temperature of the fluids and (b) permeability (primary or secondary). Composition of parental fresh glass and that of zeolitized rocks is compatible with trachyte chemistry, lightly undersaturated in SiO 2 , and the alteration processes modified the parental rock chem...
In soil stabilisation, the use of alternative products to lime or cement has been proposed. Howev... more In soil stabilisation, the use of alternative products to lime or cement has been proposed. However, the effects of these additives, of various origins, on soil behaviour and stabilizing mechanisms are not well understood. Thus, the aim of this paper is to characterize the modification of the mechanical behaviour and microstructure of two soils after treatment with one of those product, a vinyl based copolymer. After treatment, both materials were compacted up to their maximum dry density. The mechanical behaviour of the materials as a function of the curing conditions, suction and water content was first determined. In a second step, the alteration of the microstructure by the treatment product was assessed. The results showed that the treatment permitted to significantly improve the strength of the tested soils. Moreover, the efficiency of the product increases when the soil is dried. However, the Young modulus is not significantly modified by the treatment. Microstructural reorga...
Natural stones have represented one of the main building materials since ancient times. In recent... more Natural stones have represented one of the main building materials since ancient times. In recent decades, a worsening in degradation phenomena related mostly to environmental pollution was observed, threatening their conservation. The present work is focused on the minero-petrographic and geochemical characterization of black crust (BC) samples taken from the historical center of Naples, after selecting two pilot monumental areas. The latter were chosen based on their historical importance, type of material, state of preservation and position in the urban context (i.e., high vehicular traffic area, limited traffic area, industrial area, etc.). The building materials used and their interaction with environmental pollutions were studied comparing the results obtained by means of different analytical techniques such as polarized light Optical Microscopy (OM), scanning electron microscopy with energy dispersion system (SEM-EDS), X-ray powder diffraction (XRPD) and laser ablation couple...
Rendiconti Online della Società Geologica Italiana
This research is part of the PON (Programma Operativo Nazionale) SINAPSIS (SIstema NAzionale Prot... more This research is part of the PON (Programma Operativo Nazionale) SINAPSIS (SIstema NAzionale Protezione SIti Sensibili), an interdisciplinary project combining archaeological and archaeometric methods. This paper focuses on frescoes from one of the 70 funeral monuments belonging to "Porta Mediana" Necropolis, a very interesting archaeological context located in Cuma, dating back to the first half of the 3rd century BCE. The study provided detailed information on pigments and colors acquired both on untreated and treated (restored) frescoes. Portable colorimetry and chemical-mineralogical (Raman spectroscopy and X-ray powder diffraction-XRPD, respectively) analyses were performed in situ and on collected samples in order to: 1) identify pigments, raw materials and provenance, 2) point out possiblecolor changes caused by conservative treatments and/or weathering. The identified palette is typical of the Roman period; it includes both single and mixtures of two or more pigments to obtain particular hues. Moreover, the identified raw materials, such as red and yellow ochres, green frit and Egyptian blue, clearly highlighted the choice to use raw materials from local sources. The use of expensive coloring materials also suggests that the mausoleum belonged to a family or a group of people with a high social status.
Aim of this study is the characterisation of ancient Roman mortars collected in Piscina Mirabilis... more Aim of this study is the characterisation of ancient Roman mortars collected in Piscina Mirabilis, located in the important geological, archaeological and historical area of the Campania Region (southern Italy): the Campi Flegrei. Goals of this research were (a) improving knowledge of Roman construction techniques by means of detailed microstructural and compositional examination of cementitious binding matrix and aggregates, to point out both mortar mix-design and provenance of raw materials, (b) the study of secondary minerogenetic processes and (c) comparison with modern mortars. Thanks to the permission by the former Soprintendenza Archeologia della Campania (authority of the archaeological heritage) current “Parco Archeologico dei Campi Flegrei”, it was possible to collect small, non-invasive, but representative samples of mortars. Samples were studied by combined 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), simultaneous thermal analyses (STA) and mercury intrusion porosimetry (MIP). Results showed that local geomaterials were used in this archaeological site, as they are well consistent with the surrounding geological setting. A relevant characteristic is the hydraulicity of these mortars shown by the reaction rims of pozzolanic materials. Composition of the cementitious binding matrix is characterized by various products of reaction, including amorphous C-A-S-H gel, calcite and Al-tobermorite. Results also highlighted that porosity represents the main difference between ancient Roman mortars and modern hydraulic ones.
The topic of this study is the archaeometric characterization of mortars from Villa del Pezzolo, ... more 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 ignim...
Abstract The Neapolitan Yellow Tuff (hereafter NYT) is definitely the building material most used... more Abstract The Neapolitan Yellow Tuff (hereafter NYT) is definitely the building material most used in the historical architecture of Naples (Southern Italy) since Greek times. The high heterogeneity of NYT, resulting from the concomitant occurrence of lithic fragments, pumices, crystals and glass cemented by crystalline or amorphous phases, the latter highly sensitive to acid environments, define a strong attitude to weathering. This research confirmed the inhomogeneous features of this volcanic formation, within the same deposit and sometimes within the same outcrop. Based on these premises, the investigation was carried out on four most representative lithofacies, according to their different textural and petrophysical features. Actually, mechanical features are governed by two concurring factors: a) the mineralogical composition; b) the texture of the rock. In the first case, the predominance of anhydrous phases (analcime + feldspar) over zeolites improves its mechanical strength. By contrast, if the mineralogical composition is constant (similar total wt.% zeolite content), the petrophysical parameters are strictly related to the texture of the rock.
ABSTRACT Industrial minerals represent an important resource for the Italian economy, both in ter... more ABSTRACT Industrial minerals represent an important resource for the Italian economy, both in terms of exploitation and transformation, especially in those sectors for which Italy holds a leadership such as ceramics and glass. Among Italian regions Campania is one of the poorest of such kind of resources although some geological formations could be advantageously exploited. An important role is played by the deposits of sedimentary zeolites linked to the activity of different volcanic districts occurring on the Neapolitan territory such as the Campanian Ignimbrite, the most important volcanic episode of the Campi Flegrei (Southern Italy), which blankets a wide area of the Campanian region. The Campanian Ignimbrite has been thoroughly investigated from a volcanological and petrographic point of view. However, little attention was devoted to the attainment of those information useful to verify the potential of the deposit as well as the interpretation of post-depositional mineral-forming processes that have affected this deposit and have led to the formation of several facies, among which the most important are characterized by intense feldspathization (grey facies) and remarkable zeolitization (yellow facies). X-ray diffraction, X-ray fluorescence, inductively coupled plasma emission spectrometry and scanning electron microscopy methods were used to thoroughly characterize the entire set of samples collected from 31 outcrops. Data so far acquired enabled to define the role played by several parameters (i.e., temperature, alkaline and alkaline-earth cations, etc.) in influencing the zeolitization process and the consequent crystallization of phillipsite, chabazite, and analcime. Feldspathization appears to have been controlled mainly by the emplacement temperature of the deposits. The proposed genetic model involves emplacement of the pyroclastic flow in a single episode, producing a deposit with an upward-decreasing temperature gradient. In this model, the central portion had a temperature insufficient to cause significant feldspathization, and the upper portion of the formation was affected by water percolation while still hot, producing progressive zeolitization. Volcano-stratigraphical parameters suggest some constrains on the maximum temperatures affecting the central portion of WGI. Thermodynamic data on zeolites constrain the maximum temperatures of the LYT unit which likely decrease upwards in the unit up to ambient conditions in CPF.
Abstract There is a growing concern on lightweight aggregates (LWA) for recycling of waste materi... more Abstract There is a growing concern on lightweight aggregates (LWA) for recycling of waste materials: this manufacturing technology is considered a flexible tool to make it possible the conversion of large amounts of residues into building products. The main challenge for this purpose is the control on the technological behavior during firing of waste-bearing batches. The target is engineering the sintering and expansion of LWA in order to tailor bulk density, mechanical strength and water absorption on various possible applications (e.g., structural and non-structural lightweight concretes, lightweight mortars, filtration substrates, floriculture). The prediction of the aggregate expansion – and hence the batch design – is usually carried out utilizing the Riley’s and/or Cougny’s schemes, which are based on the bulk chemical composition of clay bodies. However, collecting the literature data on waste-based LWA and plotting them in the Riley’s and Cougny’s diagrams, no reliable discrimination turns out between expanding and non-expanding batches. In the same way, the attempt to modify the Riley’s and Cougny’s parameters, including elements present in wastes but not in natural raw materials, was unsuccessful. From this standpoint, a new approach to assess the batch expandability was developed through a deeper comprehension of mechanisms acting on sintering and expansion of LWA. A specific characterization protocol was set up, entailing hot-stage microscopy and determination of phase composition and microstructure. This implies a paradigm shift from batch (chemical composition) to vitreous phase (amount, chemical composition, and viscosity at high temperature). The vitreous phase plays a key-role for bloating, microstructure and physical properties of LWA. A working example is presented about new LWA based on waste glasses, ceramic tile polishing sludge and clay raw materials.
Aim of this research is an evaluation of the zeolitized facies of Campanian Ignimbrite as raw mat... more Aim of this research is an evaluation of the zeolitized facies of Campanian Ignimbrite as raw material for the production of lightweight expanded aggregates (LEA). A commercial product (Cab70) was used as reference for this rock. Tests were carried out on "pure" samples or mixed with an industrial waste mud (DPM -Dried Polishing Mud) deriving from a porcelain stoneware tile polishing process. This mud contains SiC, a phase known to act as bloating enhancer. Raw materials were subjected to mineralogical (XRPD-RIR method) and chemical (XRF) analyses. Bloating upon heating was measured (Leitz heating microscope) on Cab70, DPM and on three mixtures having the following Cab70/DPM ratios: 85/15 (Mix1); 70/30 (Mix2); 50/50 (Mix3). LEA production was assessed both in static (muffle kiln) and in dynamic (rotating kiln) conditions by firing pellets, 3-8 mm in size, between 1220-1380°C. The unit weight of the single particle was determined on fired and unfired products. All materials evidenced a decreasing density with temperature whereas the same parameter decreases with DPM increasing content. Cab70 LEAs never dropped below 0.90 g/cm 3 , even at the highest temperature, whereas DPM LEAs range between 0.86 g/cm 3 (at 1260°C) and 0.46 g/cm 3 (at 1380°C). A direct but not linear relationship between DPM content and density was evidenced. Among the three mixtures, Mix2 showed the lowest DPM content able to produce the strongest density reduction. To get LEAs with the same density the rotating kiln required temperatures generally 60-80°C higher than those of the muffle kiln. This difference should be related to the different thermal insulation of the two systems during firing. Two sets of LEAs were massively produced in dynamic conditions from Cab70 (at 1380°C) and Mix2 (at 1300°C). These latter showed better technical performances in terms of unit weight of the single particle (0.81 vs. 0.98 g/cm 3 ), bulk unit weight (460 vs. 565 kg/m 3 ), water absorption coefficients (1.4 vs. 5.5% after 24 h) and compressive strength of the particles (2.9 vs. 0.6 MPa). Differences in pore shape, dimension, abundance and spatial distribution were observed by SEM between the two sets. The technical features of these LEAs were comparable to some expanded clays, with similar grain size, commercialised in Italy.
This research provides possible opportunities in the reuse of waste and particularly muds, coming... more This research provides possible opportunities in the reuse of waste and particularly muds, coming from both ornamental stone (granite sludges from sawing and polishing operations) and ceramic production (porcelain stoneware tile polishing sludge), for the manufacture of lightweight aggregates. Wastes were characterized from the mineralogical (XRPD, X-Ray Powder Diffraction), chemical (XRF, X-Ray Fluorescence), and technological (HSM, Hot-Stage Microscopy) points of view, in order to assess their potential as bloating materials, and suitable mixes were designed. Lab simulation of the manufacturing cycle was performed by pelletizing and firing the waste mixes in a rotative furnace up to 1300 °C, and determining composition and physico-mechanical properties of lightweight aggregates. The best formulation was used to produce and test lightweight structural concretes according to standard procedures. Both granite and porcelain stoneware polishing sludges exhibit a suitable firing behaviour due to the occurrence of SiC (an abrasive component) which, decomposing at high temperature with gas release, acts as bloating promoter, resulting in aggregates with particle density <1 Mg/m 3 . However, slight variations of mixture composition produce aggregates with rather different properties, going from values close to those of typical commercial expanded clays (particle density 0.68 Mg/m 3 ; strength of particle 1.2 MPa) to products with high mechanical features (particle density 1.25 Mg/m 3 ; strength of particle 6.9 MPa). The best formulation (50 wt.% porcelain stoneware polishing sludge + 50 wt.% granite sawing sludge) was used to successfully manufacture lightweight structural concretes with suitable properties (Compressive strength 28 days > 20 MPa, bulk density 1.4-2.0 Mg/m 3 ).
expanded aggregates (LEA).Acommercial product (Cab70)was used as reference for this rock. Tests w... more expanded aggregates (LEA).Acommercial product (Cab70)was used as reference for this rock. Tests were carried out on “pure” samples or mixed with an industrial waste mud (DPM—Dried Polishing Mud) deriving from a porcelain stoneware tile polishing process. This mud contains SiC, a phase known to act as bloating enhancer. Rawmaterials were subjected ineralogical (XRPD–RIR method) and chemical (XRF) analyses. Bloating upon heating was measured (Leitz heating microscope) on Cab70, DPM and on three mixtures having the following Cab70/DPMratios: 85/15 (Mix1); 70/30 (Mix2); 50/50 (Mix3). LEAproductionwas assessed both in static (muffle kiln) and in dynamic (rotating kiln) conditions by firing pellets, 3–8 mm in size, between 1220–1380 °C. The unit weight of the single particle was determined on fired and unfired products. All materials evidenced a decreasing density with temperature whereas the same parameter decreases with DPM increasing content. Cab70 LEAs never dropped below 0.90 g/cm3, even at the highest temperature, whereas DPM LEAs range between 0.86 g/cm3 (at 1260 °C) and 0.46 g/cm3 (at 1380 °C). A direct but not linear relationship between DPMcontent and density was evidenced.Among the three mixtures,Mix2 showed the lowest DPMcontent able to produce the strongest density reduction. To get LEAs with the same density the rotating kiln required temperatures generally 60–80 °C higher than those of the muffle kiln. This difference should be related to the different thermal insulation of the two systems during firing. Two sets of LEAs were massively produced in dynamic conditions from Cab70 (at 1380 °C) and Mix2 (at 1300 °C). These latter showed better technical performances in terms of unit weight of the single particle (0.81 vs. 0.98 g/cm3), bulk unit weight (460 vs. 565 kg/m3), water absorption coefficients (1.4 vs. 5.5% after 24 h) and compressive strength of the particles (2.9 vs. 0.6 MPa). Differences in pore shape, dimension, abundance and spatial distribution were observed by SEMbetween the two sets. The technical features of these LEAs were comparable to some expanded clays, with similar grain size, commercialised in Italy. These results are worth interesting as they reveal new perspectives of application both for a rock characterized by a low exploitation cost and widely available in central-southern Italy, as well as for an industrial waste produced in high amount but not recycled at all.
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kiln) and in dynamic (rotating kiln) conditions by firing pellets, 3–8 mm in size, between 1220–1380 °C. The unit weight of the single particle was determined on fired and unfired products. All materials evidenced a decreasing density with temperature whereas the same parameter decreases with DPM increasing content. Cab70 LEAs never dropped below 0.90 g/cm3, even at the highest temperature, whereas DPM LEAs range between 0.86 g/cm3 (at 1260 °C) and 0.46 g/cm3 (at 1380 °C). A direct but not linear relationship between DPMcontent and density was evidenced.Among the three mixtures,Mix2 showed the lowest DPMcontent able to produce the strongest density reduction. To get LEAs with the same density the rotating kiln required temperatures generally 60–80 °C higher than those of the
muffle kiln. This difference should be related to the different thermal insulation of the two systems during firing. Two sets of LEAs were massively produced in dynamic conditions from Cab70 (at 1380 °C) and Mix2 (at 1300 °C). These latter showed better technical performances in terms of unit weight of the single particle (0.81 vs. 0.98 g/cm3), bulk unit weight (460 vs. 565 kg/m3), water absorption coefficients (1.4 vs. 5.5% after 24 h) and compressive strength of the particles (2.9 vs. 0.6 MPa). Differences in pore shape, dimension, abundance and spatial distribution were observed by SEMbetween the two sets. The technical features of these LEAs were comparable to some expanded clays, with similar grain size, commercialised in Italy.
These results are worth interesting as they reveal new perspectives of application both for a rock characterized by a low exploitation cost and widely available in central-southern Italy, as well as for an industrial waste produced in high amount but not recycled at all.
kiln) and in dynamic (rotating kiln) conditions by firing pellets, 3–8 mm in size, between 1220–1380 °C. The unit weight of the single particle was determined on fired and unfired products. All materials evidenced a decreasing density with temperature whereas the same parameter decreases with DPM increasing content. Cab70 LEAs never dropped below 0.90 g/cm3, even at the highest temperature, whereas DPM LEAs range between 0.86 g/cm3 (at 1260 °C) and 0.46 g/cm3 (at 1380 °C). A direct but not linear relationship between DPMcontent and density was evidenced.Among the three mixtures,Mix2 showed the lowest DPMcontent able to produce the strongest density reduction. To get LEAs with the same density the rotating kiln required temperatures generally 60–80 °C higher than those of the
muffle kiln. This difference should be related to the different thermal insulation of the two systems during firing. Two sets of LEAs were massively produced in dynamic conditions from Cab70 (at 1380 °C) and Mix2 (at 1300 °C). These latter showed better technical performances in terms of unit weight of the single particle (0.81 vs. 0.98 g/cm3), bulk unit weight (460 vs. 565 kg/m3), water absorption coefficients (1.4 vs. 5.5% after 24 h) and compressive strength of the particles (2.9 vs. 0.6 MPa). Differences in pore shape, dimension, abundance and spatial distribution were observed by SEMbetween the two sets. The technical features of these LEAs were comparable to some expanded clays, with similar grain size, commercialised in Italy.
These results are worth interesting as they reveal new perspectives of application both for a rock characterized by a low exploitation cost and widely available in central-southern Italy, as well as for an industrial waste produced in high amount but not recycled at all.