Tuff Stone Research Articles

Synthesis of zeolitic material from green tuff stone cake and its adsorption properties of silver (I) from aqueous solution

A zeolitic adsorbent was synthesized from waste green tuff stone cake by hydrothermal treatment, and its adsorption of silver ions from aqueous solution was examined for application in silver ion removal from polluted industrial waters and as a bactericide. The waste cake was composed mainly of SiO2 and Al2O3 in the form of silicate and aluminosilicate minerals, such as quartz, anorthite, muscovite and clinochlore. The cake was treated with 0–10 M NaOH solution at 80, 120 and 160 °C for 24 h, and analcime, hydroxysodalite and hydroxycancrinite were synthesized. A product with high silver adsorption ability, including analcime, was obtained in 4 M NaOH solution at 160 °C. The concentrations of Si and Al in the solution during the reaction in 4 M NaOH solution at 160 °C explain the synthesis of analcime zeolite phase due to the dissolution of quartz and anorthite in the cake, and Ag adsorption of the product depends on analcime zeolite crystals in the product. The optimal pH for silver adsorption for the product was found to be around 5. The equilibrium silver adsorption capacity was measured and extrapolated using the Langmuir and Freundlich isotherm models, and experimental data were found to fit the Langmuir model. The calculated maximum adsorption capacity of 1.10 mmol/g shows that this product is suitable for silver uptake from aqueous media. Adsorption kinetics was tested for pseudo-first- and -second-order reactions, and the rate constants of adsorption for these kinetic models were calculated. Adsorption experiments demonstrated that the adsorption process corresponds to a pseudo-second- rather than -first-order kinetics model. With decreasing aqueous solution temperature, the adsorption kinetics become slower and the amount of silver ion adsorbed increases. The thermodynamic values, ΔG°, ΔH° and ΔS°, indicated that adsorption was an exothermic and spontaneous process.

Nonlinear micromechanical model for tuff stone masonry: Experimental validation and performance limit states

In last decades, several computational strategies have been proposed for masonry structures, which form a large fraction of worldwide built heritage. In this study, a micromechanical model is proposed for tuff stone masonry by assuming a periodic composite with two components, namely tuff stones and mortar. A pressure-dependent failure rule was assigned to each component and mechanical properties were assigned according to material test results. The accuracy and robustness of the micromechanical model were assessed by simulating nonlinear response and crack patterns of masonry in different geometrical, boundary and loading conditions related to axial and diagonal compression tests. A satisfactory numerical-experimental comparison was found. Sensitivity to tensile and compressive strengths of masonry components was evaluated. Local limit states were associated with the overall nonlinear response of masonry and were statistically characterised for performance-based assessment. Finally, Monte Carlo simulations were performed to assess the influence of masonry inhomogeneity on experimental test simulations.

Radiometric analysis of volcanic tuff stones used as ornamental and structural building materials in Turkey and evaluation of radiological risk

Volcanic tuff stones are widely used to coat the interior and exterior surfaces of buildings for ornamental purposes in the construction industry in Turkey, and are also used as structural material in the construction of masonry buildings, especially in the Cappadocia region, which is a popular tourist destination. In this study, seventy-six volcanic tuff stone samples collected from different quarries located in different geographical regions in Turkey were surveyed for radiometric analysis, and the radiological risk to human health caused by ionizing radiation from natural radionuclides in the volcanic tuff stone samples was evaluated. The activity concentrations of 238 U, 232 Th, 226 Ra and 40 K analyzed in volcanic tuff stone samples were very variable, ranging from 3 to 389, 8 to 401, 2 to 263 and 99 to 2107 Bq kg -1 , respectively. The emanation coefficient and mass exhalation rate of 222 Rn measured for the volcanic tuff samples ranged from 2 to 68% with an average of 34%, and 1 to 194 μ Bq kg -1 s -1 with an average of 43 μ Bq kg -1 s -1 , respectively. The external (gamma) and internal (alpha) hazard indices, indoor absorbed gamma dose rate and the corresponding annual effective dose were estimated to evaluate the potential radiological risk to human health. The results showed that all of the surveyed volcanic tuff stone samples can be used as covering building materials for ornamental or insulating covering purposes. However, the use of some volcanic tuff stone samples as structural building materials should be restricted.

“Black particles”, the major colonizers on the ceiling stone of the stone chamber interior of the Kitora Tumulus, Japan, are the bulbilliferous basidiomycete fungus Burgoa anomala

Integrated analysis of phenotypic and genotypic characteristics of 20 isolates of “black particles” (“Kuro-tsubu” in Japanese), that mainly appeared on the plaster wall of the ceiling tuff stone surface of the Kitora Tumulus stone chamber interior in Asuka village, Nara, Japan, has identified them as the bulbilliferous basidiomycetous anamorphic fungus Burgoa anomala. Our 28S rRNA gene D1/D2 (28S) and internal transcribed spacer (ITS) regions sequence-based phylogenies indicated that the 20 isolates displayed no genetic divergence and firmly clustered with the authentic strain B. anomala CBS 130.38. These isolates and B. anomala CBS 130.38 grouped together with species of the teleomorphic genus Sistotrema and its allies in the Cantharelloid clade. Colonization of biodeteriorated murals, plaster, and stone walls as the substrata or habitats by this fungus colonized, are noteworthy. Additionally, B. anomala is recorded for the first time from Japan.

Effect of the Presence of Mortar Joints in the Bond Behaviour of Tuff Masonry Elements

In this paper, the bond behaviour of masonry elements made of tuff stone and bonded with different types of FRP fabrics (glass, carbon, basalt) has been investigated through an experimental campaign. Tuff is a natural stone representing a very common base material for the construction of masonry buildings in Southern Italy and many Mediterranean areas. Two series of specimens have been tested: 1) single blocks and 2) prisms made of three blocks and two mortar joints. The tests have been carried out according to a single-lap shear scheme according to a push-pull set-up. Presence of a plastering was also investigated for both series. The experimental results have been examined in terms of both debonding load and local stress transfer phenomena in order to evidence the performance of the different fibres and the effect of both mortar joints and plastering.

Feasibility of Using Volcanic Tuff Stone in Ground Heat Exchange for Cooling and Heating Systems in Buildings

Energy is a crucial sector in Jordan. In the world, Jordan is considered as the highest dependency on foreign energy sources, with 96% of the country's energy imported from oil and natural gas from neighboring countries. Numerically, it consumes 13% from the gross national product (GNP) costing 2.6 billion JD. The need is appearing to use new renewable resources specifically in air conditioning processes to reduce the bill of energy paid annually, in addition to the improve of practices and policies in energy sector. The current research focuses on the use of the ground heat exchange (GHE) model for cooling and heating system to improve the efficiency of the heating, ventilating, and air conditioning (HVAC) units in households and apartments using volcanic tuff stone. A GHE model was constructed by making a hole of 2 m X 1.5 m with a depth of 1.5 m, the volcanic tuff stone is placed enabling heat transfer through volume and voids of stone. The cooled air is extracted by a fan located at the exit (duct 20 X 20 cm) with electric capacity is 60 watts. The temperatures and relative humidity for air inlet and outlet were continuously measured during the period of testing. The results showed that the feasibility of using GHE model as a main part of heating/cooling system. The average temperature difference between the air inlet and exit of GHE model are or cooling and heating system respectively. Also, the relative humidity of air improves reasonably and increases in most cases.

Biofilms on Tuff Stones at Historical Sites: Identification and Removal by Nonthermal Effects of Radiofrequencies

A methodology aiming at identifying and removing biofilms from cultural heritage was applied to stones from tuff walls in historical sites. Identification of phototrophic encrusting microorganisms was carried out by optical and electron microscopy, as well as by molecular techniques (DNA analyses and denaturing gradient gel electrophoresis (DGGE)). In all sites, the examination of microbial components of biofilms resulted in the identification of 17 species belonging to Cyanobacteria, Rhodophyta, Bacillariophyta and Chlorophyta, with Cyanobacteria being the dominant components in all biofilms. In order to remove the biofilms, an innovative technique based on the use of nonthermal effects of radiofrequencies was adopted. The source of the electromagnetic fields was a signal generator connected to a horn antenna through an amplifier to provide the power boost required to generate the target field amplitude. Seven days after exposure to radiofrequency electromagnetic field, about 50 % reduction of biofilm was observed; after 14 days, biofilm extension was reduced by about 90 %. DGGE analyses performed after 14 days confirmed these visual inspections. Also, DGGE analyses carried out before and 14 days after treatments showed that 12 out of 17 identified species disappeared. A complete visual disappearance of biofilms was observed a month after the beginning of treatments. DGGE repeated at this time confirmed the total disappearance of biofilm-forming species. Treated stones, when transferred back to their original sites, did not show any microorganism re-growing after 6 months. No alteration in the color and structural consistency of tuff substrata was observed after radiofrequency treatments.

Assessment of natural radioactivity and radiation hazard in volcanic tuff stones used as building and decoration materials in the Cappadocia region, Turkey

The concentrations of natural radionuclides in 6 different colors of volcanic tuff stones which are derived from the Cappadocia region in Turkey were determined using gamma-ray spectroscopy with a HPGe detector, and the mineralogical composition and formula of stones were determined by an X-ray powder diffractometer. The average activity concentrations of 238U, 232Th and 40K are 50.7, 58.6 and 717.6 Bq.kg–1, which are higher than the world averages of 35, 30 and 400 Bq.kg–1, respectively. The radium equivalent activities (Raeq), external hazard index (Hex), and internal hazard (Hin) associated with the natural radionuclides, alpha (Iα) and gamma indices (Iγ) were calculated to assess the radiation hazard of the natural radioactivity in the volcanic tuff stones. The average indoor annual effective dose equivalent is 0.1 mSv. All values of the indoor effective dose are lower than the exemption dose value of 0.3 mSv. The calculated radium equivalent activity values vary from 60.31 Bq.kg–1 to 281.32 Bq.kg–1 with a mean of 189.78 Bq.kg–1. All values of radium equivalent activity are lower than the world average. The average indoor absorbed dose rate (Din) for volcanic tuff stones, calculated to be 21.18 nGy.h–1, is lower than the world average of 84 nGy.h–1.

Experimental investigation and numerical analysis of tuff-brick listed masonry panels

In many towns in the south of Italy are present archeological ruins, churches, castles, aqueducts, bridges, retaining walls, private houses which are made of tuff stones coupled with bricks according to a traditional technique named “listed masonry”. Although these structures represent an important part of the cultural heritage of Italy, up till now no studies, devoted to experimentally characterize this kind of masonry, are available in literature. The present paper originates from this lack and focuses on the compressive behavior of tuff-brick listed masonry panels. The results, deduced from an experimental investigation carried out by the authors during the first phase of a research program, are presented in detail. Moreover, numerical analyses aimed at emphasizing further aspects and considerations have been also performed and the obtained results have been analyzed in the light of both the experimental evidences and the directions contained in many current guidelines. The results emerged from this study underline some peculiarities concerning the role of brick-bands on the compressive behavior of the examined panels, particularly in terms of strength, stiffness and cracking configuration.

Waterproof of rock joint with lead strip for splitting tuff sheet in ancient China quarrying caverns

This paper presents the relics of rock joints caulked with lead strips, unearthed by the authors in 2007 and 2008. The relics were in ancient quarry caverns in Shepan Island, Zhejiang Province, eastern China. The quarry activities were mainly carried out for production of regular tuff stone plates about 800 years ago. Each of the lead strips was sealed into a rock joint by punching manually and carefully. At present, the lead strips still contact tightly with the rock joints and new mineral cerussite is found to have formed at the contact surfaces between the lead strip and its caulked rock joint. The use of lead strips caulking rock joints in quarry caverns is found for prevention of water from seeping out of the country rocks into quarry cavern bases, where all of the in-situ intact tuff rock was manually and near-horizontally split into thin rock sheets one by one for production of regular tuff plates. Furthermore, it is found that the tensile splitting of tuff sheets at the cavern base required the intact rocks at the cavern base had to be dry. Through this horizontal base splitting for tuff sheets from the top to the bottom, a dome-shape interior space was formed for each rock cavern with the near horizontal imprints of thin sheet layers permanently on the sidewalls.

The bioremoval of nitrate and sulfate alterations on artistic stonework: The case-study of Matera Cathedral after six years from the treatment

The bioremoval of nitrate and sulfate salts from the tuff stone surfaces of 12th century Matera Cathedral, which had been altered by nitrates and sulfates, using nitrate and sulphate reducing bacteria was performed. The bioremoval treatment was based on the direct application onto the altered stone surfaces of a previously-isolated Pseudomonas pseudoalcaligenes KF707 strain and Desulfovibrio vulgaris ATCC 29579 cells. The two strains were entrapped in a Carbogel and applied individually and together to the vertical wall; the protocol adopted included a multilayer biosystem, as a solution to maximise the efficacy of the biocleaning process on artistic stonework. The biological procedure resulted in the efficient, homogeneous removal of surface deposits and salt alterations. In fact, at 24 h the strains had removed 55% of the nitrate and 85% of the sulfate deposits, respectively. After six years from the original application the results show further improvements in microbial technology when applied to “bioremoval” and “biocleaning” of cultural heritage surface alterations.

Tuff Stone Masonry near Tower Hill in Victoria: Fragmentary Remains of Pioneer Settlement in Australia

Examples of volcanic tuff in pioneer buildings have been identified in western Victoria, Australia, in the vicinity of the Tower Hill volcanic crater. A field study has highlighted the use of tuff (notably in small domestic buildings dating to the early years of the colony) and has prompted investigation of these fragmentary and often neglected remains, including assessment of their present condition. The study and petrography of the volcanic tuffs from several cottages and a church, coupled with observations of the building stones by James Bonwick made in 1857, provide further insights into the durability and weathering characteristics of the local tuff stones. These stones are comparable to those used extensively in ancient Rome, as described by Vitruvius, who provided guidance on their physical properties and use. Recent re-assessment of the deterioration of these tuff stones has shown just how relevant that advice remains today.

Evaluation of three Italian tuffs (Neapolitan Yellow Tuff, Tufo Romano and Tufo Etrusco) as compatible replacement stone for Römer tuff in Dutch built cultural heritage

Abstract Rhenish tuffs from the volcanic Eifel region in Germany, in particular the so-called Römer tuff, are among the most prominent and voluminous natural stones in Dutch monuments. The Römer tuff has been used since Roman times, and was widely used again in Romanesque (and to a lesser extent Romano-Gothic and early Gothic) architecture. The limited (or non) availability of Römer tuff for restoration purposes is posing an increasing problem. Last decennia, the availability of Römer tuff was practically limited to blocks from the lower parts of the pyroclastic flows with abundant basalt (and other) xenoliths, giving the rock a different appearance from its traditional type; the different types of Römer tuff also demonstrate different physical and hygric properties. Given the wide use of tuff stone in Italian architecture, several Italian tuffs have been evaluated in search of a compatible replacement stone for Römer tuff. The replacement stones should approach the original as much as possible, that is, in terms of authentic appearance, physical characteristics and durability. The Italian tuffs evaluated include tuffs commercially denominated as Tufo Etrusco and Tufo Romano (from the central part of Italy) and a variety of Neapolitan Yellow Tuff (Naples region). Hygric behaviour, resistance to frost-thaw cycles, petrographic characteristics and mineralogy of Italian tuffs have been determined and compared with original Römer tuff. In all three cases, resistance to frost-thaw cycles is unfortunately shown to be considerably less than that of original Römer tuff. In addition, hygric expansion of the Neapolitan Yellow Tuff appeared to be considerably larger than that of original Römer tuff. Of the tuffs evaluated, the variety of Neapolitan Yellow Tuff is a good match with the original Römer tuff in terms of visual appearance. It has already been sparsely used in the Netherlands in minor amounts. However, the durability characteristics require additional evaluation.

Metrological definition and evaluation of some mechanical properties of post-medieval Neapolitan yellow tuff masonry

The knowledge of the morphological and mechanical properties of masonry walls is very important for the refurbishment of ancient buildings, particularly when the requirements of both structural safety and historical preservation must be fulfilled. The masonry is not of homogenous material: its mechanical properties depend on stones, mortar, and texture which are very variable due to their dependence on the historical periods and the geographical area of the erection. For this reason, a deep knowledge of masonries built in different sites and historical periods is essential in order to evaluate both the capacities of bearing vertical load and the seismic vulnerability of the masonry structure. Three fundamental typologies of tuff masonry have been defined: they are the characteristics of different historical periods from the XVI to the XX century. The models are in full-scale in order to reproduce the three defined chronotypes. Original tuff stones quarried in the corresponding historical period, mortars similar to the original ones, reproduced according to ancient documents and original constructive techniques have been used for the construction of the specimens. Compression tests performed in displacement control have been carried out on the masonry models in order to determine the maximum resistance of the material and the corresponding strain, the ultimate strain and corresponding residual strength. In this paper, the procedure used for making the specimens and for experimentally evaluating the mechanical properties of post-medieval Neapolitan yellow tuff masonry are illustrated and the obtained results, even in terms of plastic capacity of these kinds of masonry, are reported.

New polymeric nanocomposites for improving the protective and consolidating efficiency of tuff stone

Abstract Nanocomposite systems based on the commercial polymer Fluormet CP and different amounts of the Cloisite 30B organoclay (1, 2 and 4 wt%) were tested as protective and consolidating agents for the Neapolitan yellow tuff. The conservation and restoration efficiency of these treatments was evaluated through physical investigations (water capillary absorption, permeability to water vapor, abrasion resistance and mechanical properties) and aesthetic-morphological observations (colorimetric measurements and SEM analyses). The results have evidenced that the nano-scale dispersion of low amounts of Cloisite 30B into the polymeric matrix enhances the consolidating and protective action of Fluormet CP. In fact, yellow tuff stone treated with the nanocomposite systems exhibits a more marked reduction in water absorption and water vapor permeability as well as improved mechanical and abrasion resistance with respect to stone treated with the neat Fluormet CP. Furthermore the applications of these nanocomposites systems do not alter the chromatic appearance of the stone substrate and not considerably modify the reversibility properties of the original polymeric matrix.

The use of tuff stone cladding in buildings for energy conservation

Heating the houses in cold climates requires large quantities of heat energy to be spent. The building sector consumes more energy in the form of heat than other sectors. Therefore, considerable energy savings can be obtained by using natural rocks with low thermal conductivity in insulating the buildings. In this study, the amount of energy conserved by using porous tuff stone in external walls of buildings is calculated. It was shown that considerable energy savings can be achieved by using tuff stone for facing buildings in cold climate zones such as Isparta region. The cost of installing tuff stone panels for facing buildings will be paid back in four years by savings in heat energy.

Quantification of weathering processes in an acid brown soil developed from tuff (Beaujolais, France): Part II. Soil formation

Mineralogy and chemical properties of the fine earth and particle size fractions were examined with total chemical analysis, selective chemical analyses and X-ray diffraction. Clay minerals were investigated using microprobe and transmission electron microscopy. The chemical changes during soil formation were calculated from results of the chemical weathering mass balance. The study soil is of the brown acid type, unsaturated and poor in short-range ordered products. All soil fractions sized between 0 and 1 cm originate from transformation of the weathered rind developed around tuff stones, where chemical weathering is intense. The same weathering reactions which were initiated in the early stages of tuff weathered rind were continued in the soil with strong dissolution of plagioclases and transformation of biotite. Two chemical weathering reactions led to the formation of clay minerals in the soil: the precipitation of kaolinite into biotite pseudomorphs and into the small white mica and the transformation of the biotite (BI) into hydroxy-interlayered vermiculite (HIV) with intermediary stages shown in HIV-BI interstratified minerals, which were defined (95–75% of biotite layers). Pure vermiculite or V-BI interstratified minerals were hydoxy-interlayered, even in the weathered rind of the tuff. The chemical and mineralogical mass balance between the weathered rind and the soil shows a heavy dissolution of andesine (90%) and to a lesser extent of albite (55%) and of apatite (60%), a precipitation of kaolinite and a transformation of biotite into HIV. The plagioclase dissolution in weathered tuff was almost complete, while there were only traces remaining in silt. The biotite has almost disappeared in the fine earth fractions due to dissolution and transformation into HIV.

Quantification of weathering processes in an acid brown soil developed from tuff (Beaujolais, France): Part I. Formation of weathered rind

The petrographical and mineralogical composition of tuff in the studied area was determined by optical microscopy, X-ray analysis, bulk chemical analysis and mean chemical composition of each mineral obtained from the electron microprobe. The tuff stones sampled on the surface and in the pits of soil are usually surrounded by a bleached rind. From the results of chemical weathering mass balance (isovolumetric calculations), the chemical and mineralogical transformation are quantified during the formation of this weathered rind. This tuff from the Upper Visean was composed of about 45±5% phenocrysts (quartz, andesine, albite and biotite) and about 55±5% devitrified groundmass (spherolites: quartz, K-feldspar, albite, andesine and biotite). This series was a broad monotonous series although some facies diversity occurred, i.e., colour and density of plagioclase phenocrysts, evidence of fluidality. A local heterogeneity in the tuff mineralogy and a variation in its chemical composition (K 2O, CaO, Na 2O and loss on ignition) have been induced by devitrification of the groundmass and hydrothermal alteration. The contact metamorphism seemed to have caused the groundmass devitrification and recrystallization of biotite phenocrysts as small biotite crystals (<0.1 mm). Hydrothermal alteration has led to biotite chloritization, transformation of plagioclase (albite and andesine) into white mica and K-feldspar, and a few veins (quartz, chlorite, epidote). In the `Montagne des Aiguillettes', tuff weathering appeared as a thin bleached rind around all stones. The weathering gradient inside rinds corresponded to a progressive dissolution of tuff minerals: quartz<K-feldspar<white mica<biotite<albite<apatite<andesine. The weathering processes were characterized by a strong dissolution of plagioclases and apatite (increase of voids by about 12%) and to a lesser extent by the transformation of micas (biotite) into hydroxy-interlayered vermiculite (HIV) and mica-HIV mixed-layer minerals and by kaolinite (KA) precipitation. The results of the petrographical study were consistent with the calculated mass balance. The weight losses were about 18% and corresponded to a strong exportation of CaO, Na 2O, Sr, P 2O 5, Al 2O 3 and SiO 2 (74; 62; 51; 42; 17 and 25%, respectively) and an increase in the water content. Eighty-two percent of andesine, 41% of apatite, 40% of albite, and biotite (<3%) were dissolved. The increase in the total water content corresponded to the formation of hydrated weathered minerals (2.6% of HIV and 4.3% of KA).

LASER ARGON DATING AND GEOLOGICAL PROVENANCING OF A STONE AXE FROM THE STONEHENGE ENVIRONS*

The recently‐developed laser microprobe 40argon‐39 argon technique has been used to give a geological date for a rhyolitic tuff stone axe fragment from the Stonehenge environs. The method requires only milligramme‐sized samples and gives dates of sufficient accuracy to aid in provenancing artefacts to sources, as well as information on the heating history of samples. The axe sample is of Lower Carboniferous date (341 ± 5 Ma) and this limits possible sources to outcrops within the Scottish Midland Valley and small altered exposures in Dartmoor. X‐ray fluorescence analysis of the axe suggests the Scottish Midland Valley as the more likely source. The laser argon analysis also shows that the implement had not been heated in antiquity. Laser argon‐argon dating can, therefore, be a useful tool in artefact study.

The Crypt Of St. Carlo Alle Quattro Fontane In Rome

The Church of St. Carlo alle Quattro Fontane, designed by Francesco Borromini, is a masterpiece of the Italian Baroque. The appearance of deformations and cracks in the vault of the crypt called for the insertion of props. Historical research was carried out to ascertain the original shape and compare it with the deformations visible today. Investigations revealed that the vault was built in good quality pozzolanic concrete mixed with irregular tuff stone blocks. Structural analyses were carried out using finite element models, taking into account the non-linear behaviour of the vault's material. The results show how the peculiar shape of the vault reduces the safety margins with partializations of sections; cracks have expanded slowly over the years, probably also in relation with the high sensitivity to horizontal displacement produced by little soil settlements. Interventions were designed taking into account also the high artistic and historical value of the building, respecting Borromini's original concept. It as therefore decided to use a system of prestressed tie bars, placed along the radius through the vault, anchored at the edges and connected, in the central area, by a stainless steel elliptical ring placed at the intrados of the vault itself.