María J. Mosquera

Universidad de Cádiz | UCA

The main aim of this research is to characterise fresh stone and to highlight how its physical properties change as a result of natural ageing. For this purpose, naturally weathered and freshly cut samples, proceeding from the monument, were analysed. The results obtained allow us to better understand the behaviour of the material in relation to de...

Many of the concrete structures that conform our modern cultural heritage are in need of repair and protective interventions. Silane-based impregnation treatments can be used to repair onset cracks and reinforce the surface due to their ability to produce silica and C-S-H gels, and can be modified by incorporating hydrophobic precursors to create m...

Despite concrete being the most prominent building material of the twentieth century, the cultural heritage relevance of concrete buildings and the importance of their preservation is not widely recognized. The European Union project InnovaConcrete’s purpose is to develop nanotechnology-based treatments for concrete preservation and to increase cit...

The effectiveness of sol-gel based treatments for the protection of concrete depends on their capacity to penetrate into the material pores. Optimization of sol formulation to achieve maximum penetration depth is not a straightforward process, as the influence of different physical properties of the sol varies with the pore size distribution of eac...

This manuscript presents a 4 years in-situ evaluation of TiO 2 /SiO 2-based product applied to a mortar seating belonging to the bleachers of the Cadiz Roman Theatre, affected by biofouling and organic deposits. Antifouling performance was studied by colorimetric measurements and ATP analyses. Surface sampling was performed for biofouling identific...

Superhydrophobic coatings have been often used to protect stone surfaces against water. The durability of these coatings has been rarely tested for monumental heritage exposed to outdoor conditions. In this work, a highly effective superhydrophobic nanomaterial has been applied in the archaeological site of Carteia, which is located next to the sea...

In this work, we employ a versatile laser-based top-down approach that allows to create superhydrophobic and hydrophobic surfaces, with controlled roughness and wetting properties, on marble and potentially other building materials. The process involves two stages: (1) application of an organically modified silica coating to reduce surface energy....

In this study, the pre-consolidation of the granite used in the north façade of St. Martin’s Cathedral in Ourense, of Romanesque style (S. XII–XIII), and its influence on the effectiveness of a subsequent desalination treatment using poultices of different composition is presented. The need for both treatments lay in the high degree of deterioratio...

In this study, the newly synthesized TiO 2 and N doped TiO 2 clusters were added to silica sol to synthesize N-TiO 2 /SiO 2 composites via the sol-gel method. Afterwards, the prepared sols were applied by brushing on portland cement. Doping with nitrogen significantly increased the absorption of TiO 2 towards the visible region, thus, increasing th...

A Self-cleaning nanostructured TiO2 coating has demonstrated the capacity to mitigate undesired effects from air pollution. Not only it reduces the deterioration of building materials but may also prevent certain pollution-related human health problems. In this study, mesoporous TiO2/SiO2 photocatalysts were synthesized in order to produce self-cle...

This manuscript presents a 1 year in the laboratory and 3 years In-Situ evaluation of an alkoxysilane-based consolidant containing SiO2 nanoparticles (SiO2NPs) on Ostionera stone, a biocalcarenite traditionally employed in Southwestern Spain. Cádiz Roman Theatre was selected for In-Situ application and testing. In order to safeguard the theatre, pr...

The composition and structure of Calcium-Silicate-Hydrate (C-S-H) phases depends on various reaction parameters leading to its formation. Molecular Dynamic simulation studies probing the formation and structure of C-S-H are generally computationally expensive and can reach only very short time scales. Herein, we propose a coarse graining approach t...

Water and waterborne decay agents (e.g. salts, microorganisms) are commonly associated with undesired alterations and damages on concrete elements. A strategy to mitigate their impact is to decrease water retention in the material either by surface treatments or admixtures. In this work, hydrophobic concretes were developed by the addition of a hyd...

Building materials decay is caused by the combination of chemical, physical and biological aspects. Therefore, the development of innovative multifunctional building materials is an alternative to reduce their impact. This can be achieved by post-treatments or by direct changes in the fabrication of synthetic materials, such as engineered stone. Th...

Surface treatments, especially hydrophobic agents to prevent water ingress and consolidants able to fill decay-induced cracks, are often proposed as a method for preserving stone cultural heritage, however its use to protect concrete heritage is much less common. New products, specifically designed for concrete, have been developed. These products...

Alkoxysilane-based consolidation treatment are commonly employed in restoration and conservation works of Cultural Heritage buildings. However, their poor affinity to carbonate stones is well-known. In this paper, we evaluate three consolidant treatments (two of them modified to incorporate hydrophobic or photocatalytic properties), formulated to c...

Microbial fouling on the surface and water retention are common problems affecting porous ceramic materials (stone, concrete…) that can alter their properties, shorten their service life and even pose a health risk. Though proper maintenance (disinfection, drainage…) can mitigate these issues, it is a time and resource intensive process and prevent...

Chemical compatibility with a wide range of materials is among the features that has driven the use of alkoxysilanes as consolidants in built structures. Such compatibility is particularly important in cementitious materials where the reaction with portlandite may generate C-S-H gel, one of the main hydration phases of OPC. The cementitious matrix...

Protective coatings with hydrophobic or biocide properties are commonly employed to prevent biofouling of building materials exposed to the environment. Although the factors affecting bioreceptivity of the base materials are well known, the influence of the coating and/or biocide agent surface properties on the interaction with the cell surface is...

Surface-modified Ag/TiO2 photocatalysts with enhanced activity under visible light and biocidal properties have been produced through a two-stage method involving the functionalization of TiO2 nanoparticles(NPs) with –SH or –NH terminated alkoxysilanes and deposition of AgNPs. The functionalization process increased the yield of the Ag deposition a...

The performance of impregnation treatments used for protection and remediation of porous building materials relies on sufficient penetration depth. The penetration of sol–gel impregnation products into partially saturated porous material is driven by capillary suction and depends on material properties, such as pore size distribution on one hand, a...

Impregnation treatments are one of the alternatives to protect concrete-based building and monuments from weathering degradation. However, it is important to consider the chemical compatibility of the reaction products with the building material. The impregnation product studied here consists of a silica oligomer able to poly-merize, by a simple so...

Two factors are key in the design of a TiO2 photocatalyst for building materials that meets the requirements for environmental applications: the TiO2 light absorption restricted to UV and its poor adhesion to the substrates. In this work, two strategies of TiO2 modification, nitrogen doping and AuNPs deposition, were combined in order to promote th...

The biosynthesis of ultra-small gold nanoparticles (AuNPs) with very narrow size distribution and stable dispersion through an aqueous drago (Dracaena draco L) aged leaf extract used as a non-toxic reducing and stabilizing agent has been achieved. The gold nanoparticles obtained in this way, have a size in the range 0.9–2.8 nm and an average size o...

Au/N-TiO2 photocatalysts with enhanced photoactivity thanks to nitrogen doping and gold nanoparticles (AuNPs) controlled deposition onto titania have been obtained bymeans of a simple and innovative one-pot synthesis promoting synergetic activity between these two approaches. The activity of the materials under study was evaluated by methylene blue...

The air pollution is becoming one of most important health problems around the world. Thus, the development of depolluting building materials is a crucial challenge. TiO2 is a photocatalyst with demonstrated performance for degradation of NOx and other typical pollutants. However, its limited absorption of solar light reduces its performance. In th...

Although silicon alkoxides (especially ethylsilicates) have long been used as consolidants of weathered stone monuments, their physical properties are not ideal. In this study, an innovative procedure for the consolidation of sedimentary rocks was developed that combines the use of organometallic and alkylamine catalysts with the addition of well-d...

Even if silicon alkoxides (especially ethylsilicates) have long been used as consolidants of weathered stone monuments, their physical properties are not ideal. In this study, an innovative procedure for the consolidation of sedimentary rocks was developed that combines the use of organometallic and alkylamine catalysts with the addition of well-de...

Colonization by phototrophic microorganisms causes a range of problems for building façades, The combination of biological physical and chemical agents accelerates the decay of materials. For this reason, in recent years there has been a growing interest in the application of multifunctional treatments that combine consolidant and biocidal action....

In this work, the self-cleaning and photocatalytic properties of mesoporous TiO2/AuNRs-SiO2 composites (namely UCA–TiO2Au) prepared by a simple and low-cost technique were investigated toward application in building materials. Mesoporous photocatalytic nanocomposites coating the surface of stone and other building materials are a very promising app...

An effective procedure has been developed to consolidate and hydrophobize decayed monumental stones by a simple sol-gel process. The sol contains silica oligomer, silica nanoparticles and a surfactant, preventing gel cracking. The effectiveness of the process on biocalcareous stone samples from an 18th century cathedral has been evaluated, and it w...

Water is the main factor of degradation in most stone monuments and buildings, and especially in those located next to the sea, since it acts as a vehicle for decay agents. The continuous exposure of the Baelo Claudia Roman archaeological site to marine aerosol has produced severe weathering. The aim of this study was to assess the performance of a...

A novel alkoxysilane-based product was applied on limestone samples from a Roman archaeological site. The study consisted of an initial phase to evaluate site environmental conditions in order to choose the most suitable product type to be applied. The decay that was produced in the site is mainly caused by natural action, with water being the main...

The high pollution levels in our cities are producing a significant increase of dust on buildings. An application of photoactive coatings on building materials can produce buildings with self-cleaning surfaces. In this study, we have developed a simple sol-gel route for producing Au-TiO2/SiO2 photocatalysts with application on buildings. The gold n...

Most products commonly employed in the restoration and conservation of cultural heritage stone have not been specifically developed to preserve such elements. In addition, they are plagued by limited performance and structural drawbacks such as low adhesion, poor penetration, and cracking. Another disadvantage is the requirement for most products t...

Water is the main vehicle of decay agents in Cultural Heritage building materials exposed to weathering. In this work, a simple method to produce superhydrophobic/oleophobic coatings building materials, including under outdoors conditions, has been developed. In addition, a study of the behavior of the developed coatings on different substrates (li...

In this work, the consolidation of a granitic medieval necropolis in NW Spain severely affected by a granular disintegration is presented. The causes of this degradation were first diagnosed and, given the need to consolidate the altered surfaces, the effectiveness of two newly synthesized nanoconsolidants (UCAD-2o and UCAT-do) were evaluated and c...

Nowadays, producing building surfaces that prevent water and oil uptake and which present self-cleaning activity is still a challenge. In this study, amphiphobic (superhydrophobic and oleophobic) building surfaces were successfully produced. A simple and low-cost process was developed, which is applicable to large-scale building surfaces, according...

A well-known drawback of sol−gel materials is their tendency to crack because of the high capillary pressure supported during drying. We have pioneered a facile and low-cost route to obtain monolithic xerogels, from a silica precursor and a surfactant, mixed under ultrasonic agitation. This route presents a clear interest for practical application...

Three innovative strengthening, protective and self-cleaning agents for marble and calcareous stones were synthesized by using a simple sol-gel route at ambient conditions. TiO2 nanoparticles and hydroxyl-terminated polydimethylsiloxane (PDMS) were incorporated in a tetraethoxysilane (TEOS) matrix in the presence of oxalic acid (Ox). Both the Ox co...

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/SiO2 nanocomposites with application as a multifunctional protective treatment for building s...

Superhydrophobic materials can find promising applications in the field of building. However, their application has been very limited because the synthesis routes involve tedious processes, preventing large-scale application. A second drawback is related to their short-term life under outdoor conditions. A simple and low-cost synthesis route for pr...

Nowadays, PLA is one of the most promising alternatives to the petroleum-based polymers, since it can be obtained from renewable sources. An innovative application of PLA is to protect the exterior of buildings. PLA compounds meet an important requirement of products for conservation, which is their reversibility. This paper describes a simple proc...

The synthesis of improved photocatalysts capable of removing pollutants deposited on building surfaces is an important challenge for researchers nowadays. By using a simple and low-cost process we have synthesized mesoporous Ag-TiO2-SiO2 photocatalytic coatings that meet the requirements of outdoor application. These are new materials designed to g...

In this article, the protocol to identify the most suitable consolidant to be applied in a granitic Romanesque church form Galicia is presented. The study consisted in two phases: an initial laboratory evaluation during which the treatment with a nanoconsolidant never applied on granite is compared with the treatment with two commercial consolidant...

Nowadays, the enhancement of atmospheric pollution is dramatically increasing the presence of soiling on buildings in every city of the world. Thus, the development of photocatalysts as self-cleaning coatings is a promising challenge. The first object of this work was to develop a simple synthesis route for obtaining SiO2-crystalline TiO2 nanocompo...

This study evaluates the efficacy of a tetraethoxysilane used as consolidant (Estel 1000) and a nanoconsolidant based on silicon oligomers modified with n-octylamina (UCAD-2o) in two types of granitic rocks. The application of these products was carried out under different moisture conditions in the rocks, evaluating the consolidant efficacy, the c...

We describe the results of electromigration desalination of two soluble salt-contaminated Galician granites. The efficacy of electromigration, which had not been previously applied to granite, was assessed for two types of granite contaminated with a 20% NaCl solution and seawater. Desalination effectiveness was evaluated as follows: (1) analysis o...

Numerous superhydrophobic materials have been developed in recent years by using a combination of two strategies: reducing the surface free energy and roughening the surface. Most of these procedures have the serious drawback of involving tedious multi-stage processes, which prevent their large-scale application, such as on the external stone and s...

This study presents the evaluation of the effectiveness of two crack-free nanoproducts with consolidant and consolidant/hydrophobic properties. The consolidant product was obtained from a silica oligomer in presence of a surfactant, whereas the consolidant/hydrophobic product, was obtained with the addition of an organic component, PDMS, to the sta...

The present research has been carried out at Physical Chemistry Department of University of Cadiz , in the context of a project that joined the University of Palermo and the University of Cadiz. The aim was to evaluate the self-cleaning effectiveness of a titania-silica nanoproduct applied on stoneware tiles samples, taken from a building in Palerm...

A TiO2–SiO2 nanocomposite material was formed inside the pore structure of a very friable carbonate stone by simple spraying of a sol containing silica oligomers, titania particles and a non-ionic surfactant (n-octylamine). The resulting nanomaterial provides an effective adhesive and crack-free surface layer to the stone, and gives it self-cleanin...

Atmospheric pollution has an evidently adverse impact on the esthetics of urban buildings and structures. Thus, the synthesis of photocatalysts capable of removing pollutants deposited on the surface of stone and other building materials is a challenge to researchers. By a simple and low cost process we have synthesized mesoporous TiO2–SiO2 photoca...

A mesoporous TiO(2)-SiO(2) nanocomposite photocatalyst has been prepared from TiO(2) nanoparticles and ethoxysilane oligomers in the presence of a non-ionic surfactant (n-octylamine). The 2D and 3D structure properties of the resulting nanomaterial are described. The use of 3D techniques, particularly HAADF-STEM electron tomography, together with 3...

The study presents the results of a research, developed in collaboration between the Universities of Palermo (Italy) and Cádiz(Spain). It concerned the laboratory experimentation of some nanostructured innovative products, aimed at the consolidation and protection of historical stone surfaces from the Greco-Roman quarter in the Valley of the Temple...

ABSTRACT: This study presents the effectiveness evaluation of two crack-free nanomaterials with Consolidant and consolidant/hydrophobic properties, respectively, developed at the University of Cadiz, in the context of the Master in “Nanotechnology and Nanomaterials for Cultural Heritage” of the University of Palermo. The consolidant product was obt...

This article describes a sol-gel route for nanomaterials production, without volatile organic compounds (VOCs). These materials are simply obtained by mixing a silica oligomer with a non-ionic surfactant under ultrasonic agitation. The surfactant acts as sol-gel transition catalyst and also as an agent that directs the pore structure of the materia...

Mesoporous titania-silica composites that have photocatalytic activity have been synthesized by mixing ethoxysilane oligomers and titanium dioxide nanoparticles in the presence of a nonionic surfactant (n-octylamine). The resulting nanomaterials create effective adhesive and crack-free coatings for stone. These coatings give self-cleaning propertie...

We have developed a simple sol–gel treatment procedure that enhances the properties of pure limestones to make them more suitable for commercial use; in particular, we have improved the mechanical robustness of the stone. When treated, the stone also has enhanced hydrophobic, water-repellent, and stain-resistant properties, which have been evaluate...

A customary procedure in the protection of monumental buildings is the consolidation of decaying stone by the application of commercial products containing tetraethoxysilane (TEOS). These products polymerize within the porous structure of the decaying stone, significantly increasing the cohesion of the material. However, TEOS-based consolidants suf...

Soluble salts of marine origin are one of the main agents in the weathering of granitic rocks used in buildings and monuments; they cause a loss of cohesion between the mineral grains, which results in granular disintegration. This deterioration is produced by crystallization–dissolution processes of salts, mainly sodium chloride, in the interior o...

A challenging objective in monumental stone restoration is to synthesize crack-free silica materials for application as consolidants. Hydrophobicity is also a valuable property for such products; it is important to prevent the penetration of water because water is the main vehicle by which the agents of decay enter the pore structure of the stone....

The sol-gel process has been found to be successful in applications for the conservation and restoration of stone. However, a well-known drawback of the materials obtained by this process is their tendency to crack during drying inside the pores of the treated stone. In this article, we present an overview of our current research centred on produci...

Ibuprofen (an anti-inflammatory drug) has been loaded onto two different surfactant-templated silicas (SBA-15 and MCM-48). To evaluate the effect of the drug-solvent combination on the loading capacity of the silica, we have performed ibuprofen adsorption experiments using 10 different solvents; we have interpreted our experimental results assuming...

Abstract The effects of storage humidity on the properties of hydroxypropylmethylcellulose (HPMc)-based hydrophilic matrix tablets were investigated. Hydrochlorothiazide tablets prepared with HPMCs of different thickening capacities were stored for 6 months (a) at a relative humidity corresponding to the prestorage equilibrium moisture content of t...

Monolithic gels, prepared from different mixtures of colloidal silica in a sol solution containing tetraethoxysilane under powerful ultrasonic agitation (sonosols), were compacted at an isostatic pressure of 390MPa. Then N2 adsorption-desorption data were used to construct structural models of the gels using Monte-Carlo calculations on the basis of...

A novel sol-gel synthesis, in which a surfactant acts to make the pore size of the gel network more coarse and uniform, is shown to provide an effective alternative for the consolidation of stone. The new mesoporous silica avoids the main inconvenience of current commercial consolidants, which is their tendency to crack inside the pores of the ston...

We propose an innovative strategy to obtain crack-free gels by using a surfactant as a template for the silica pores. We use a neutral surfactant –n-octylamine – which weakly interacts by hydrogen bonding with the silica precursor. This allows it to be removed by simple drying in ambient air. We investigate the effect of the surfactant in simple in...

The main focus of this work is to determine the effect of cement addition, a common practice in many restorations, on the pore structure of lime-based mortars. A second target is to establish correlations between microstructure and water vapor transport across the mortar, which is a key characteristic of building decay. In order to achieve these ob...

Several mixtures obtained by ultrasonic agitation of colloidal silica with a sol solution containing tetraethoxysilane (TEOS) were used to form crack-free monoliths. The dry gels that were submitted to mercury porosimetry showed differences in behavior according to the proportion of silica colloid in the gel. For low proportions, the mercury isosta...

A saline-spray artificial ageing test was used to simulate the effects produced in granites and sedimentary rocks (calcarenites, micrites and breccia) under conditions in coastal environments. Three main points were addressed in this study: the durability of the different kinds of rock to salt decay, the resulting weathering forms and the rock prop...

The object of this paper is to evaluate behaviour during drying of two stone consolidants: Wacker OH and Tegovakon V, containing tetraethoxysilane. During drying, the gel network contracts due to capillary pressure generated by solvent evaporation. When the consolidant dries inside the stone porous structure, the shrinkage is constrained in all thr...

Since mortars play a key role in buildings decay, their suitable choice is critical to the success of restoration projects. The focus of this paper is to characterise the pore structures of a set of mortars and correlate them with mechanical properties and vapour permeability, which are relevant to the decay of granite buildings. Water vapour trans...

Since mortars play a key role in buildings decay, their suitable choice is critical to the success of restoration projects. The focus of this paper is to characterise the pore structures of a set of mortars and correlate them with mechanical properties and vapour permeability, which are relevant to the decay of granite buildings. Water vapour trans...

Alkoxysilanes, low-viscosity monomers that polymerize into the porous network of stone by a sol–gel process, are widely used in the restoration of stone buildings. We have used the mercury porosimetry technique to characterize changes in microstructure of three granites following their consolidation with two popular commercial products (Wacker OH a...

Consolidation treatments are commonly used in the conservation and restoration of stone buildings and monuments to strengthen the stone and increase its resistance to further deterioration. The consolidants are believed to modify the microstructure of the granitic rocks. This chapter evaluates the effects of the two silicic consolidants, Tegovakon...

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