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Abstract Climate change poses an ever-increasing risk to our stone built heritage. Among conservation actions, the use of consolidant products is considered a possible response to this challenge, and the adoption of nanolimes has been widely studied showing promising results. However, while the effectiveness and method of application has been assessed, few studies have probed the changes in drying kinetics following treatment. In fact, a drastic alteration of the water transport might lead to further anomalies. This study investigates the influence of nanolimes dispersed in ethanol on the drying kinetics of Clipsham limestone using cavity ring-down spectroscopy. The degree of treatment was assessed by gravimetry, Raman spectroscopy, optical microscopy, colorimetry, optical profilometry and thin section analysis. Results showed an increase in the dry mass, observable colour changes and decrease in surface roughness. Small but reproducible increases were observed in the evaporation flux for phase I behaviour following treatment, however, no changes were observed in the total mass of water released or the phase II diffusivity. Determination of the activation energy associated with phase II drying was unchanged following treatment . These results indicate that following treatment there has been little-to-no change in the internal surfaces and structure of the stone to affect vapour transport.

Climate change poses an ever-increasing risk to our stone built heritage. Among conservation actions, the use of consolidant products is considered a possible response to this challenge, and the adoption of nanolimes has been widely studied showing promising results. However, while the effectiveness and method of application has been assessed, few studies have probed the changes in drying kinetics following treatment. In fact, a drastic alteration of the water transport might lead to further anomalies. This study investigates the influence of nanolimes dispersed in ethanol on the drying kinetics of Clipsham limestone using cavity ring-down spectroscopy. The degree of treatment was assessed by gravimetry, Raman spectroscopy, optical microscopy, colorimetry, optical profilometry and thin section analysis. Results showed an increase in the dry mass, observable colour changes and decrease in surface roughness. Small but reproducible increases were observed in the evaporation flux for phase I behaviour following treatment, however, no changes were observed in the total mass of water released or the phase II diffusivity. Determination of the activation energy associated with phase II drying was unchanged following treatment. These results indicate that following treatment there has been little-to-no change in the internal surfaces and structure of the stone to affect vapour transport. [ABSTRACT FROM AUTHOR]

Since the 1940s, when maritime archaeology was established, the systematic excavation of submerged wrecks began to be refined. Systematic excavations led to the recovery of a vast array of organic and inorganic artefacts, including human and non-human bones and teeth. In order to preserve the materials recovered from the sea, the discipline of maritime conservation rapidly expanded and dealt with unique issues, including, but not limited to, marine salts’ encrustation of archaeological artefacts. Bone and teeth are organic artefacts which provide crucial information about natural and social environments of the past. When recovered from marine settings, they are often friable and require conservation processes and consolidation treatments, e.g., to prevent shrinkage during drying. However, conservation processes and consolidants can interfere with pathological, traumatic and taphonomical evidence associated with bone and teeth, and can bias sample preparation and analysis through mechanical action and chemical composition. The aim of this paper, in which a few examples of interference are listed, is to highlight the need of accurately documenting any type of conservation process and/or consolidation treatment that has been performed on bone and teeth stored in archaeological collections. This becomes essential when samples are selected for study, especially if this includes destructive analysis, and will assist in clarifying any conflicting results, leading to reliable interpretations.

Since the 1940s, when maritime archaeology was established, the systematic excavation of submerged wrecks began to be refined. Systematic excavations led to the recovery of a vast array of organic and inorganic artefacts, including human and non-human bones and teeth. In order to preserve the materials recovered from the sea, the discipline of maritime conservation rapidly expanded and dealt with unique issues, including, but not limited to, marine salts' encrustation of archaeological artefacts. Bone and teeth are organic artefacts which provide crucial information about natural and social environments of the past. When recovered from marine settings, they are often friable and require conservation processes and consolidation treatments, e.g., to prevent shrinkage during drying. However, conservation processes and consolidants can interfere with pathological, traumatic and taphonomical evidence associated with bone and teeth, and can bias sample preparation and analysis through mechanical action and chemical composition. The aim of this paper, in which a few examples of interference are listed, is to highlight the need of accurately documenting any type of conservation process and/or consolidation treatment that has been performed on bone and teeth stored in archaeological collections. This becomes essential when samples are selected for study, especially if this includes destructive analysis, and will assist in clarifying any conflicting results, leading to reliable interpretations. [ABSTRACT FROM AUTHOR]

Tarihi yapıların cephelerinde kullanılan kagir yapı malzemeleri, çevresel ve doğal faktörler nedeniyle detay kaybına uğrayıp hızla bozularak yapısal hasara uğramaktadır. Taşların bozulmasını önleyerek bozulma derecelerini yavaşlatabilmek için koruma çalışmaları doğrultusunda sağlamlaştırıcı ve su itici koruyucu kimyasal malzemeler kullanılmaktadır. Bu çalışmada, İstanbul’da, farklı özelliklerde üç önemli tarihi yapının koruma çalışmalarında sağlamlaştırıcı ve su itici kimyasal malzemelere karar verme sürecinde geliştirilen yöntem ele alınmıştır. Bu süreç, disiplinler arası bir hiyerarşiye dayandığı için öncelikle, bu tarihi yapıların alan çalışmalarında yönetim, planlama, karar verme, uygulama, denetleme aşamalarında aktif rol oynayan ve birbirleriyle iş birliği içinde çalışan uzmanlara ortak bir anket çalışması yapılmıştır. Anket çalışmasının verileri ışığında, üç tarihi yapıda, koruyucu kimyasal malzemeler ile yüzey iyileştirme uygulamaları yapılmıştır. Bu çalışmada geliştirilen yöntem ile in-situ ortamda yapılan koruyucu kimyasal uygulamalara karar verilirken hangi parametrelere dikkat edilmesi gerektiğini belirtmek, koruyucu malzemelerin seçimi ile ilgili gerekli kriterler önermek ve in-situ ortamda yapılan koruyucu malzemelerin uygulanmasında standartların önemini vurgulamak amaçlanmıştır.

Creases and folds in Chinese paintings and calligraphies scrolls are hard to avoid during the handling in storage and exhibitions. The creases are usually reinforced with paper strips in the conservation treatment. However, adhering the paper strips will create unwanted secondary creases along the joining edge on the painting scrolls after repeated openings and rolling. This study proposes a new consolidant, bacteria cellulose (BC), for the conservation of creased Chinese painting scrolls. Different tests were carried out and the results showed that BC was a better approach than the traditional paper strip reinforcement method. The method not only had an excellent effect on conserving the creased artwork on Xuan-paper aesthetically, but also improved its physical properties. [ABSTRACT FROM AUTHOR]

The synthesis of a refractory geopolymer with excellent thermal and mechanical properties to develop materials that resist temperatures above 1000 °C has become a challenge in recent years. The production of a refractory material involves the combination of clays and alkaline substances, whose formulation produces an improvement in the final properties of the refractory material. In this work, we report a Taguchi L18 design to synthesize a refractory geopolymer that exhibits the highest compressive strength, based on two natural clays from Mexico, seashells, sodium silicate and water. The prepared mixture was molded to form mini bricks, which were cured for 24 hours at room temperature. Subsequently, the bricks were dried for 4 days, and we evaluated the effect of temperature at 40 °C, 60 °C and 80 °C. Subsequently, the samples were subjected to calcination between 900 °C and 1200 °C to determine the resistance to both thermal and mechanical fracture via compression. The highest thermal resistance and compressive strength were obtained with a geopolymer formulated with 7.5 % seashells, 38.2 % Tepozán‐Bauwer clay, 30.0 % Kaolin clay, 20 % commercial sodium silicate and 4.3 % water, which was dried at 40 °C. The compressive strength was 7.28 MPa (74.2 kgf /cm2), and the thermal resistance was up to 1200 °C. In the FTIR analysis of the geopolymers calcined at 1200 °C, the influence of calcium was observed by the bands of the 800–1200 cm−1 region, where there was a greater distribution since the Si−O− bond was added. Ca was found at 950 cm−1. By adding CaCO3 in the form of seashells, the presence of the anorthite mineral phase (CaAl2Si2O8) can be identified, which originates from the degradation of calcium carbonate crystals (calcite, vaterite and aragonite) of the identified seashells using XRD. The synthesized geopolymer has potential use in the refractory and ceramic materials industry. [ABSTRACT FROM AUTHOR]

In this work, innovative, sustainable, multifunctional surface treatments for tuff protection that combine water-repellency, consolidating function and long-lasting antimicrobial activity were developed and tested. In particular, different water-based formulations were prepared by adding to a commercial polysiloxane treatment a biocide against biodeterioration, or clay nanoparticles to strengthen the tuff or their combination where the biocide was partially loaded into the nanoclay to join protective, consolidant and long-lasting biocide activity. The last formulation showed the best overall performances, since the constituents synergically improve its water-repellency and aggregative effectiveness without changing the color. Moreover, all surface treatments showed promising antimicrobial activity.

• Keratin–MgSO 4 treatment consolidated heavily deteriorated waterlogged wood with maximum moisture content (U max) values > 400% and yielded anti-shrink efficiency values of >87%. • The ASE of keratin–MgSO 4 -treated WLW increased with an increase in WPG. • The combination of keratin and MgSO 4 provided high dimensional stability to the fragile waterlogged wood. • SEM and TEM analyses indicated that the keratin–MgSO 4 treated-middle lamella was significantly reinforced than the keratin-treated middle lamella. Keratin treatment modified by adding a magnesium salt treatment process was used to conserve heavily deteriorated archaeological waterlogged wood. In this study, the deteriorated waterlogged wood specimens of Quercus sp., Aphananthe aspera , and Acer sp., whose maximum moisture content (U max) values >400%, were treated with a combination of keratin and magnesium sulfate (MgSO 4). This modified treatment provided satisfactory stabilization to all the waterlogged wood specimens. Scanning electron microscopy and transmission electron microscopy analyses indicated that the keratin–MgSO 4 -treated middle lamella was significantly reinforced compared to the keratin-treated middle lamella. The results of the stabilization by the keratin–MgSO 4 treatment indicate that this keratin–MgSO 4 treatment has a great potential for use as a green consolidation method. [ABSTRACT FROM AUTHOR]

A study to improve the performance of andesite mortar and rock consolidated with tetraethylorthosilicate (TEOS) sol and a solvent of ethanol in the presence of titanium tetraisopropoxyde (TTIP) and silica particles has been conducted. The improvements include minimizing the shrinkage using silica particles from rice husk ash, rheological property suitability of the consolidant, and mechanical properties of the consolidated mortar and rock. The effect of TTIP concentration, ethanol volume, and addition of the silica particles on rheological properties of TEOS-based consolidant, and also mechanical properties of the consolidated mortar and rock were evaluated. The results showed that the increase of TTIP content in the consolidant shortens the gelling time, and the weight percentage ratio of TTIP:TEOS:ethanol of 5%:55%:40% was the optimum composition for the consolidation. Consolidation of andesite block using that composition significantly increased the compressive strength up to 57.61% (0.58 kgf/mm2). The addition of 2% of silica particles into the consolidant decreased the gel shrinkage and increased the Young modulus of the mortar. The presence of water in the andesite matrix reduced the consolidation performance, and 0.5% was the maximum percentage of water content acceptable for the consolidation.

Stone has been widely used as a construction material since ancient times, and its preservation is crucial in historical and contemporary buildings. Biodeterioration and other alterations cause damage in stone monuments which leads to the need for repeated actions. Nanotechnology is increasing the development of new products for construction and restoration, and new treatments based on nanoparticles have been developed for stone conservation, such as biocides or consolidants. These treatments avoid the disadvantages of traditional products, such as limewater for consolidation or quaternary ammonium salts as biocides and fulfil some of the requirements demanded by cultural heritage, i.e., effectiveness, compatibility with the stone and its aesthetic values, and durability. This manuscript reviews some of the main advances in the development and application of nanoparticles as consolidants and biocides to treat stone cultural heritage. [ABSTRACT FROM AUTHOR]

In Turkey, masonry building materials, especially natural stones used on the facades of historical buildings and monuments bearing the traces of many different civilizations, are rapidly deteriorating due to many factors. For the sustainability of historical buildings' cultural heritage value, preserving the original masonry material in situ is much more critical, especially since the old stonework is starting to disappear today. For this reason, stone conservation studies are carried out to slow down the deterioration processes and reduce the degree of deterioration by preventing further deterioration of the stones. During these studies, consolidant and/or water repellent chemical applications are developed within the scope of stone consolidation applications and applied to masonry building materials. As a result of this research, it is aimed to draw attention to consolidant and/or waterrepellent chemical applications, which are few studies on the subject in Turkey, to increase knowledge. And then, it is aimed to emphasize the need for standardization in Turkey and contribute to the intended use of these irreversible chemical applications to have a certain quality. In line with these purposes, a method proposal has been developed that can be used to preserve original masonry building materials in historical buildings, especially in stone conservation studies, according to the international standards and specifications used in stone consolidation studies in the world. [ABSTRACT FROM AUTHOR]

• New technique for radiocarbon dating artefacts contaminated by preservative. • Successful dating of early medieval triangular wooden (alder) bowl treated with PEG. • Ramped pyroxidation can isolate suitable CO 2 fraction. • Modelling of thermal decomposition profiles validates results. • Use of FTIR to confirm presence of PEG. Preservatives and consolidants make it difficult or impossible to obtain accurate radiocarbon dates on many organic artefacts from museums or archaeological collections. Discovered in an Irish bog in the 1960s, the Cuillard Bowl is a triangular wooden (Alder - Alnus glutinosa) dish of special interest on account of its unique geometry and style. However, the persistence of preservative (polyethylene glycol, PEG) following conventional pre-treatment methods produced problematic radiocarbon dates. A new ramped pyroxidation (RPO) setup at the 14CHRONO Centre was applied to pretreated material from the Cuillard bowl to investigate if a preservative-free CO 2 fraction could be isolated, taking advantage of the release of CO 2 from wood cellulose at a lower decomposition temperature than CO 2 is released from PEG. Radiocarbon dates on low temperature fractions (280–340 °C) produced statistically identical radiocarbon ages that calibrate from the mid-6th to mid-7th centuries AD, in agreement with stylistic dating of the bowl. The validity of these results is further supported by models of the radiocarbon ages from theoretical thermal decomposition curves of PEG-contaminated wood. Higher temperature fractions (> 350 °C) were statistically different and older due to the removal of CO 2 derived from the PEG preservative. RPO and infrared-spectroscopy (FTIR) results on non-pretreated Cuillard bowl material, early medieval alder of known age (dendro-dated), and modern alder were used to identify PEG as the preservative and to provide references for the thermal behaviour of both clean and heavily contaminated wood in the RPO system. This work demonstrates the development of a new technique for radiocarbon dating of organic artefacts that are contaminated by PEG, offering a new avenue for the investigation of museum or archaeological collections previously considered too difficult date. [ABSTRACT FROM AUTHOR]

Currently the application of consolidants based on nanoparticles is common practice among restorers. Consolidants should not modify the properties of original materials according to international recommendation, which requires previous studies to decide the optimal option. The selection must be based on empirical results, and not only in the expertise of the restorer, because the consolidant’s effectiveness is influenced by its own properties and other factors such as the characteristics of the artwork (elemental composition, porosity, texture, etc.) and its context (temperature, relative humidity, etc.). Moreover, new protocols must be sustainable and compatible with on-site restoration. A new protocol to test consolidant nanoparticles has been designed and assessed. This is based on easy trials and low-cost techniques—digital microscope, colorimeter, peeling test and ultrasound—that could be employed by restorers in situ. In this paper, different consolidant nanoparticles were tested on stones from two historical quarries. The first treatment was SiO2 nanoparticles, and the second, a new nanocomposite of Ca(OH)2 and ZnO quantum dots that allows us to measure penetration depth easily and discern the treated areas under UV lights. This second treatment was the best option for the studied stones, validating the protocol designed for the choice of consolidants.

• The consolidating and adhesive properties of funori are described. • SEM analysis and mechanical tests confirm the consolidation of common and ancient paper. Aim of the present work was to deepen the knowledge on the effects of funori on cellulose fibers with particular attention paid to their consolidation. Compared to canvas, paper samples (untreated or artificially aged) show different fiber packaging and liquid-absorbing properties. Herein, we conducted observations of cellulose fibers by scanning electron microscopy (SEM) in order to evaluate the seaweed extraction method employed in this work, as well the consolidation action had on the fibers through multiple additions of the prepared solutions. Surface homogeneity and fiber stiffness observed by us increased over time and the fibers, initially frayed and disordered, were eventually incorporated into the purified funori after several solution additions accompanied also by a progressive occlusion of the pores. The achieved consolidation effect was confirmed by means of mechanical tests. Moreover, the method herein developed was slightly modified in view of the application of the funori solution to a cultural asset of historical and botanical interest, still scarcely studied. Electronic microscopy allowed us to evaluate the consolidation and gluing effect obtained through subsequent funori applications. [ABSTRACT FROM AUTHOR]

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Highlights • The use of agar can improve the acid rain resistance ability of limestone. • The structures of HA-coated stone samples were investigated. • Acid rain resistance properties of stone treated with DAP/agar/consolidant were evaluated. Abstract In this article, the effects of adding a small amount of agar to the diammonium hydrogen phosphate (DAP) solution were investigated in order to increase the ability of limestone to resist acid. The results of FTIR, XRD, BET and SEM showed that the structure of calcium phosphate phases remained almost unchanged, except that its crystallinity was affected as a consequence of the agar addition. Compositional and morphological analyses show that reacted limestone surfaces develop calcium phosphate phases with a plate-like structure. A double application (as both coupling agent and consolidant) was also investigated, in which the samples were treated with DAP followed by a TEOS-based consolidant product. Resistance to acid rain on limestone treated with the DAP/agar and consolidant resulted in a decreased deterioration rate. [ABSTRACT FROM AUTHOR]

The main aim of our current investigation is the colorimetric evaluation of protective treatments (consolidants) applied to traditional Islamic plasterworks, under natural ageing conditions. From analyses of the original pictorial plaster remains in the Courtyard of the Maidens of the Real Alcázar in Seville, Spain (a World Heritage Site) we prepared test specimens, using materials and techniques similar to the original ones. We analysed 56 test specimens painted with four pigments (yellow, green, blue, and red), using two different binders (animal glue and gum arabic), onto which five representative consolidants were applied: barium hydroxide, acrylic copolymer, polyvinyl butyral, ethyl silicate, and bacterial carbonatogenesis. The test specimens were subjected to natural ageing for one year (indoors and outdoors), enabling a colorimetric assessment to be made of the changes of the polychrome surfaces. The colorimetric heterogeneity of the 56 specimens after ageing registered an average value of 2.7 CIELAB units, assessed using the mean colour difference with respect to the mean. In the aged specimens, the addition of consolidants resulted in average colour differences (mainly lightness differences) of 10.7 and 6.7 CIELAB units, considering as a reference the specimens without consolidants aged indoors and outdoors, respectively. These colour differences were very similar for both binders but not for the four pigments, higher values being found for the blue and red pigments. Considering as reference the samples without consolidants aged outdoors, we found no statistically significant colour differences, either among the five consolidants (p = .094) nor the two binders (p = .674) used. In addition to the magnitude of colour differences, the choice of the most appropriate consolidants must also consider aspects related to performance and effectiveness. Overall, for the type of paints tested, the polyvinyl butyral consolidant appeared to perform the best, followed by the ethyl silicate. [ABSTRACT FROM AUTHOR]

Abstract Tetraethoxysilane or tetraethyl orthosilicate (TEOS), also known as ethyl silicate, traditionally applied to consolidate stone, has recently begun to be used on Portland cement mortars and concrete with promising results. TEOS not only fills the pores in the substrate, but reacts with the cement favouring the precipitation of new C-S-H gels that densify and strengthen the materials. This study explored the effectiveness of new TEOS-based treatments bearing nanosilica (NS) or nanolime (NC) and their compatibility with cement materials found in the built heritage, given the participation of the various products in the pozzolanic reactions that may induce additional C-S-H gel. The physical and hydric properties (mechanical strength, porosity, surface gloss and colour, water vapour permeability and low pressure water absorption) of a Portland cement mortar were determined before and after applying the consolidants. Ethyl silicate alone or in conjunction with nanolime (4:1) proved to most effectively raise material strength and improve water repellence while conserving the original colour and gloss. [ABSTRACT FROM AUTHOR]

To preserve fragile organic cultural objects in humid archaeological excavation sites, a moisture-curable polyurethane (MCPU) as a consolidant was synthesized and employed. Relevant instruments were utilized to test properties such as colour, transmittance, mechanical properties, hydrophobicity and ageing resistance. Furthermore, residues of Zhusi, a vessel made of plant fibres excavated in archaeological sites, were consolidated. The results illustrated that MCPU cured for 12 h formed transparent, colourless and flexible films. The transmittance of the cured films was over 80% in the wavelength range of 400-1100 nm. The tensile strength was 1.419 MPa, and the elongation rate was more than 1500%. The thermal ageing equation is lg τ = 5383.6639/T − 12.5728 (τ is the lifetime of the samples in hours and T is the thermodynamic temperature in K), meaning that at 15 °C, its lifetime is approximately 147 years. The Zhusi consolidation experiment showed that the mechanical properties were improved and deteriorated fibres were perfectly bonded, and the separated and broken fibres formed a complete structure without significant variation in appearance. Therefore, MCPU can be used as a consolidant for fragile organic cultural objects in very humid archaeological excavation sites. This work solves the problem of conservation of fragile organic objects in humid environments. [ABSTRACT FROM AUTHOR]

The presented study focuses on evaluating the efficiency of a gelatin-based product that incorporates a plasticizer (glycerol) and a biocide (citronella oil), proposed as an eco-friendly adhesive for polychrome decoration applied in different parts of the architectural complex of the Longshan Temple in Lukang (eighteenth century, Taiwan). Seven laboratory physico-chemical tests were performed: (a) viscosity measurement; (b) drying curves; (c) moisture content determination; (d) water vapor permeability test; (e) mechanical test; (f) adhesion test; (g) susceptibility to fungi colonization test, which provide information on the workability, water content and water barrier properties, as well as mechanical, adhesion, and the biocide properties of the proposed product. The obtained results indicate that the workability, mechanical and adhesive properties of the new adhesive are adequate. Permeability in polychromies is slightly reduced due to the additional barrier effect of the adhesive incorporated into the paint film. The efficiency of citronella oil for preventing the growth of fungus Aspergillus niger on paintings consolidated with the adhesive was also probed. In parallel to these laboratory trials, the micro-invasive tests carried out, using nanoindentation combined with atomic force microscopy (NI-AFM), provided direct evidence for the improvement in the mechanical properties induced by applying the new adhesive to the original polychromies. [ABSTRACT FROM AUTHOR]

This study evaluated the self-cleaning ability and durability of Si-based consolidants (an ethyl silicate consolidant and a consolidant based on nanosized silica) spiked with nanocrystalline TiO2 activated by either UV-A radiation (spectral region between 340 and 400 nm, and main peak at 365 nm) or UV-B radiation (spectral region between 270 and 420 nm, and main peak at 310 nm). Granite samples were coated with consolidant, to which nanocrystalline TiO2 was added at different concentrations (0.5, 1, and 3%, by wt.). Diesel soot was then applied to the coated surfaces, and the samples were exposed to UV-A or UV-B radiation for 1650 h. The surface color changes, relative to the color of untreated granite, were determined every 330 h by color spectrophotometry. Slight color changes indicated a recovery of the reference color due to the degradation of the soot. The final surfaces of both the untreated and treated surfaces were compared by stereomicroscopy and scanning electron microscopy. The main findings were that: (1) In general, the consolidant containing nanosized silica induced the most intense photocatalytic activity. In the more compact xerogel coating formed by the nanosized silica, more TiO2 nanoparticles were available to interact with the radiation. (2) For all consolidant mixtures, soot degradation remained constant or decreased over time, except with ethyl silicate with 0.5 wt % TiO2 (no self-cleaning capacity). (3) Soot degradation increased with the concentration of TiO2. (4) The UV-B radiation was the most effective in terms of soot degradation, except for the surface coated with the ethyl silicate and 3% wt. TiO2.

In the process of protection and consolidation of valuable materials, the efficiency is the crucial property that needs to be considered. TiO2/ZnAl layered double hydroxide (LDH) coating and silicate- and carbonate-based consolidants were synthesized and proposed to be used for protection and consolidation of four porous mineral substrates: brick, stone, render and mortar. The photocatalytic efficiency of TiO2/ZnAl LDH coating, as well as consolidation efficiency of two consolidants, both applied on model substrates, were studied. The photocatalytic coating showed significant activity and performed well after the durability tests involving rinsing and freezing/thawing procedures. After treatment with both consolidants, a serious enhancement of consolidation of the used substrates was found. On the other hand, the application of TiO2/ZnAl LDH, as well as consolidants, caused negligible changes in the water vapour permeability values and in appearance of the porous mineral substrates, indicating a high level of compatibility.

The composites of silica-titania that have consolidant and self-cleaning property have been synthesized by mixing titania and colloidal silica. The coating of stone using silica-titania could improve the mechanical properties of andesite stone. In addition, the coating created the superhydrophilic properties and similar visual appearance with untreated andesite. The self-cleaning performance of treated andesite could remove the 92% of congo red and 67% of methylene blue as staining agents through photocatalysis process. [ABSTRACT FROM AUTHOR]

In recent years, there has been increased interest in examining alternative polymers for the conservation of archaeological artefacts, particularly waterlogged timbers, providing better, renewable, greener alternatives to poly(ethylene glycol) (PEG). The degradation of PEG consolidants in the timbers of the sixteenth century warshipMary Rosehas been examined and the rheological and thermal properties of PEG have been compared with its monomethyl and dimethyl ethers and several polysaccharide consolidants (chitosan, guar, and 2-hydroxyethyl cellulose) in order to evaluate their potential as alternative consolidants for the conservation of waterlogged wooden artefacts. Additionally, the effect of the polymers on the archaeological wood was characterised by thermogravimetric analysis and solid-state nuclear magnetic resonance spectroscopy. The results suggest that the future of conservation technologies lies with polysaccharide consolidant materials, which show enhanced compatibility with wooden artefacts with no detectable side effects while also being cheap, with extremely low toxicity, renewable, and sustainably resourced. [ABSTRACT FROM PUBLISHER]

The goal of the paper is the investigation of synergistic action of newly developed consolidants and LDH_TiO 2 photocatalytic suspension on the characteristics (antifungal efficiency and surface properties) of the selected mineral substrates: brick and render. There were two different application protocols employed: protocol (1) the fresh photocatalytic suspension was applied on already consolidated substrates aged for 1, 2, 4 and 7 months, and protocol (2) only once on all specimens aged 1 month after the consolidant application. This study provides an insight into the synergistic effect of the applied materials on the antifungal activity, hydrophilicity and performances of the substrates’ surface during UV irradiation. The decrease of OH − ions on the surface, revealed from the photocatalytic suspension, showed a positive effect on the surface stability and antifungal properties of the mineral surface. Based on the obtained results, the most suitable protocol for the application of the photocatalytic suspension on the already consolidated and aged porous substrates has been adopted. [ABSTRACT FROM AUTHOR]

The decay of building materials is generally caused by the combination of chemical, physical and biological agents. Therefore, the development of products that combine multiple protection mechanisms is desirable. We have developed, via a sol-gel route, CuO/SiO 2 nanocomposites with application as a multifunctional protective treatment for building stones. In this work, we demonstrate that CuONPs act as a catalyst of the sol-gel process and promote the formation of nucleation centers, affecting the final structure of the nanocomposites. We also conclude that the nanocomposites increase mechanical resistance and decrease microbial growth of two reference laboratory microorganisms (bacteria and yeast) on a typical building limestone. Moreover, the release of Cu 2 + ions is the most likely mechanism for the biocidal effect. Finally, we find that the highest concentration of CuONPs, in the studied range (0.00–0.35% w / v ), was not the most effective because it causes a NPs precipitation, decreasing the biocidal effect, and the resulting material is heterogeneous and fragile. An intermediate proportion of CuONPs provides a suitable consolidant and biocide performance. [ABSTRACT FROM AUTHOR]

In the last twenty years Funori has become known outside Japan thanks to its capacity not to modify the appearance of the painted surface. Moreover, because of the similar chemical nature of Funori and cellulosic fibres that make the textile support, conservators have supposed Funori can restore depolymerised fibres. The experimentation just started from this assumption and it tried to verify that supposition.

Thermal and mechanical properties were determined for the halloysite nanotubes (HNT)/beeswax composites at various compositions. The beeswax degradation temperatures and time course, provided by thermogravimetry (TG), evidenced the improvement of the thermal properties operated by HNT. Differential scanning calorimetry (DSC) allowed us to determine the enthalpy of melting as well as the time course of the melting process for beeswax. A slight loss of beeswax crystallinity was observed upon HNT addition. The dynamical mechanical analysis (DMA) provided the loss and the storage modulus for the nanocomposites upon heating and it was shown that the nanoclays create an inorganic framework which enhances the mechanical properties keeping unaltered the beeswax shape even above the melting temperature. To the light of these insights, samples of waterlogged archaeological wood were consolidated with the HNT/beeswax nanomaterial. The amount of HNT entrapped into the pores as well as the shrinkage volume of wood samples were determined. The HNT/beeswax mixtures can be considered a promising consolidant material for archaeological wood. [ABSTRACT FROM AUTHOR]

Works of art are constantly under physical, chemical and biological degradation, so constant restoration is required. Consolidation is an important step in restoration, and traditional approaches and materials have already shown their limitations. To solve these problems, new nanoparticle-based consolidants were developed. No information on their toxicity is yet available. In this work, we focused our attention on potential risks posed by three commercially available nanoparticle-based consolidants: silica (SiO 2 NPs), silanized silica (silanized SiO 2 NPs) and calcium hydroxide (nanolime) nanoparticle dispersions. Occupational exposure impact was tested on three in vitro models mimicking inhalation, dermal contact and systemic routes. While no toxic effects were observed for nanolime and silanized SiO 2 NPs, bare SiO 2 NPs showed a dose- and time-dependent damage in all considered models. Corrosion test on EpiSkin® revealed no viability reduction. Works of art degradation is partially due to microorganism activity. Consolidant antibacterial activity was evaluated on three representative bacterial strains. Silica NPs-based consolidants showed effect on specific bacterial groups, while no specificity was observed with nanolime. In conclusion, silanized SiO 2 NPs-based consolidant emerged as the safest and bacteriologically active product. The different biological impact of bare and silanized SiO 2 NPs highlights the importance of safe-by-design approach in developing nanoparticle-containing products. [ABSTRACT FROM AUTHOR]

Stucco monuments suffer from many causes of deterioration; one of these is the transformation of the gypsum content of stucco to anhydrite, which causes disintegration and the appearance of fine fissures that sometimes culminate in the complete loss of archaeological stucco material; this problem makes thinking of a new protocol for its treatment very urgent. So the research proposes using sulphate activators, which may lead to retransformation of anhydrite to gypsum and thus will participate in protecting our stucco heritage. Many parameters have been used; including XRPD analysis, XRF, FTIR, measurement of physical and mechanical properties, SEM and aging by sodium chloride. All results proved that sulphate activator solutions have the ability to retransform anhydrite to gypsum and to increase the mechanical strength of stucco material. [ABSTRACT FROM AUTHOR]

Many natural and synthetic products have been used for the consolidation of paint layers, but none have been thoroughly tested for this application. This is apparent for most of the synthetic and semi-synthetic adhesives for conservation, many of which are pure polymer resins and dispersions adapted from other industries. They were not specifically formulated with the appropriate properties for conservation, nor do they take advantage of some of the more recent developments in adhesive technology. BEVA® 371 is unique among adhesives used for consolidation treatments, as it is a multi-component mixture and was designed specifically for the conservation field using the best technology available at the time. However, the main focus of the research was its application as a lining adhesive. Thus, optical properties and stability, specifically color stability, were not thoroughly evaluated even though some lining applications that were first recommended could have benefited from this type of investigation. This paper will discuss the development of BEVA® 371, the chemistry, and roles of each component, and address a practical concern about the tack behavior of its replacement formulation, BEVA® 371b. [ABSTRACT FROM AUTHOR]

This study explored the effectiveness of tetraethyl orthosilicate (TEOS) as a Portland cement mortar consolidant to verify whether it meets the requirements for use in cultural assets. TEOS was found to raise cement mortar strength, lower its porosity and permeability and occasion minimal alteration in its appearance, an indication of its suitability to conserve heritage mortar works. FTIR and 29 Si MAS NMR studies supported the notion that TEOS interacts with the hydrated phases of the cement, portlandite and C–S–H gel. The reaction product between portlandite and TEOS was C–S–H gel and between TEOS and C–S–H gel was a gel with longer chain. [ABSTRACT FROM AUTHOR]

Organic-inorganic hybrid material used as consolidant for earthen relics was synthesized by adding silica nano particles into polysiloxane with the presence of surfactant. This composite material is less hydrophobic than other polymer consolidant, which can avoid the preservation damage caused by the incompatibility between the hydrophobic consolidant and the hydrophilic soil. The tensile strength of the synthesized consolidant is close to other rubbers, which can relieve the stress between consolidant and soil within the expansion-shrinkage process when environmental conditions change. The product was applied on ancient Liangzhu city wall and its effectiveness was examined. [ABSTRACT FROM AUTHOR]