Teresa Rivas

Teresa Rivas
University of Vigo | UVIGO · Department of Natural Resources and Environment Engineering

Dr.

About

156
Publications
16,356
Reads
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2,610
Citations
Additional affiliations
November 2009 - present
University of Vigo
Position
  • Lecturer
Description
  • Mineral processing technologies-Mine Engineer Degree; Ornamental and industrial rocks-Mine Engineer Degree; Analytical methods applied on cultural heritage-Máster HTCO3; Soil Contamination and remediation technologies. Máster on Environmental engineering.
January 2007 - December 2012
University of Vigo
January 1999 - December 2003
University of Santiago de Compostela
Education
October 1996 - October 1996
September 1985 - July 1990

Publications

Publications (156)
Article
Sol-silicate paints and polyvinyl acetate paints with similar red and green colour tones were applied to concrete and brick specimens and underwent either natural outdoor exposure in a marine setting for 12 months or accelerated ultraviolet radiation exposure (total exposure 4620 h). Chromatic changes were regularly monitored via spectrophotometer...
Article
In the field of stone conservation, a very common direct intervention seeks to increase the water repellence of objects. By limiting the interaction between the solid and the water, the possibility of alteration due to the action of the water (liquid or solid) as well as that related to the colonisation of surfaces by organisms is reduced. To decre...
Article
Graffiti spray paints are commonly used in contemporaneous mural paintings in public spaces, contributing to the transformation of sites and urban life. These outdoor artworks are now beginning to show different deterioration forms, such as physical-mechanical alteration (loss of material and cohesion, etc.) and chromatic changes. However, the dete...
Article
Three cleaning methods, namely i) a commercial biocide applied by brush with the subsequent extraction of organic remains by a rod, ii) a scalpel or iii) a Nd:YVO 4 laser at 355 nm, single application as well as paired combinations, were tested for removing from a granite two different crustose lichens: Diploschistes scruposus (lighter with a clear...
Article
Among many other issues, characterisation of construction techniques is very interesting for understanding protohistoric societies. In the case of Iron Age sites in the Iberian Peninsula, knowledge about materials and construction techniques is minimal. This work explores the challenges of the characterisation of earth mortars in Iron Age sites in...
Article
Full-text available
Solar radiation is one of the deterioration factors par excellence of modern urban artworks, as among other manifestations, it causes loss of colour. This deterioration can compromise the durability of the works, although it is not known to what extent this durability can vary depending on the substrate supporting the paint. We evaluated the suscep...
Article
Full-text available
In order to improve our knowledge of the weathering response of tempera paints exposed to an industrial atmosphere, azurite-and malachite-based paint mock-ups prepared with either rabbit glue or egg yolk binders were artificially aged in an SO2 rich atmosphere. The aim was to identify the different alteration mechanisms and forms of degradation in...
Article
Full-text available
The behavior of historic tempera paints exposed to pollutant gases is an important issue when developing conservation strategies. In this work, binary tempera paint mock-ups that were made with either smalt or lapis lazuli pigments mixed with either rabbit glue or egg yolk binders were exposed to an SO2 accelerated aging test in order to find out m...
Article
Laser cleaning is an environmentally friendly method based on laser ablation processes to remove impurities or contaminants from a surface layer of a material. The configuration of a laser station in the case of flat surfaces is not complicated because laser irradiates from a fixed position. In contrast, controlled laser processing of 3D surfaces i...
Article
Laser ablation is an accepted cleaning technology for cultural heritage stonework. Optimized laser ablation may, however, have different side effects depending on the mineralogical composition of the stone. In the case of granitic rocks, observed side effects - colour changes, fracturing or/and mineral melting - have been attributed to laser parame...
Article
Gypsum black crust is one of the most severe deterioration forms affecting the built Cultural Heritage (CH) worldwide. Its removal from granitic substrates is necessary since gypsum layer favours the deterioration of the rock. This study investigates the laser assisted removal of gypsum black crust, from a Hercynian granite from the NorthWest (NW)...
Article
The use of adhesives to repair stone is a common conservation and restoration practice. Thermoplastic (acrylic) and thermostable (epoxy, polyester, etc) adhesives are often combined to take advantage of the benefits of both types. An intervention layer in the form of an acrylic adhesive is typically previously applied to enhance the reversibility o...
Article
Full-text available
Conservation strategies to reduce the degradation of stone caused by the action of water are focusing on increasing the hydrophobicity of the surface by imitating existing solutions in nature (lotus leafs and others). These are mainly based on the existence of hierarchical roughness with micro-and nanoscale structures. In the case of marble, resear...
Article
The application of electrokinetic techniques for the mobilization and the removal of ions present in different porous materials, such as building construction materials, have shown high efficiency with respect to that reached with other techniques. However, some drawbacks related mainly with the mobilization efficiency of the ions of interest and w...
Article
Mechanical methods to extract undesired graffiti paints on ornamental stones are efficient cleaning methods from an economical point of view. However, effort on the optimization of mechanical cleaning procedures to avoid any damage to the substrate is required for large areas. In this study, two ornamental stones with different composition and text...
Article
The effects of the four common commercial finishes (polished, honed, disc cutting and bush hammering) on several properties of ornamental granites were evaluated. Two granites of different texture, widely used as ornamental stones in NW Iberian Peninsula, were selected. Roughness, colour and reflectance (properties used as cleaning indicators of cu...
Article
Cleaning effectiveness of four graffiti spray paints artificially aged by SO2 exposure on granite was evaluated.Two different removal procedures were applied: i) mechanical methods with different micro abrasives (Hydrogommage– combining action of air, water and micro abrasive-silica or aluminium silicate and IBIX– combining action of air and micro...
Article
Soluble salts are among the most harmful alteration agents affecting the building materials. In recent years, several researches have been devoted to counteract alterations induced by soluble salts using electrokinetic techniques. However, the applicability of these techniques for conservation purposes remains limited due to adverse side effects, s...
Article
Laser-assisted removal of unwanted layers is well established in Cultural Heritage (CH), however material extraction and potential side-effects to the substrate must be reliably determined and monitored. Several non-invasive analytical techniques have been employed after cleaning, but on-line assessment of the process itself and its consequences on...
Article
Currently, removal of graffiti from stone monuments is a particularly challenging task. Lasers, being highly controllable and precise tools with minimal chemical waste, offer a key solution in this respect and a significant amount of research has been dedicated to this subject. Studies related to the laser cleaning of carbonate stones (such as lime...
Article
This paper presents a study of the efficiency of two chemically different anti-graffiti coatings (sacrificial and permanent anti-graffiti products) on two different compositional and textural granitic stones, Rosa Porriño and Albero. First, both uncoated and coated surfaces of the granites were characterized using stereomicroscopy and scanning elec...
Article
This paper addresses the evaluation of the cleaning of crustose lichens developing on granite. The evaluation was performed considering the effectiveness of the cleanings and harmfulness exerted on the granite. The laser cleaning of lichen was compared with the most conventional procedure, scalpel. The combination of both procedures was also tested...
Article
Interferometric profilometry and hyperspectral imaging techniques combined with traditional analytical techniques such as spectrophotometry, stereomicroscopy, X-ray diffraction, scanning electron microscopy, particle size analysis, and thermogravimetry were used to characterize tempera paint mock-ups. These paint mock-ups were prepared as binary mi...
Article
In this study the effectiveness of an electrokinetic consolidation treatment applied on granite was evaluated. The efficacy of this treatment was compared to that obtained by applying a commercial consolidation product (Tegovakon®). The parameters evaluated were: (1) dry matter after treatment of each product; (2) modifications caused in the physic...
Article
Granitic stones are widely used in the field of Cultural Heritage in the north-western Iberian Peninsula. In some activities regarding conservation, such as the laser cleaning, it is of great interest the identification of the minerals on the granitic stone surface in order to improve the treatment and to avoid damages by means of the adaption of t...
Article
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...
Article
The polymineralic characteristic of granite implies an additional challenge during the laser cleaning of cultural heritage built of this rock, because the forming-minerals experience different behaviours under the laser radiation, leading to damages of variable nature and intensity. The aim of this work was to identify the ranges of fluence to sati...
Article
This paper is focused on the reliability of the colour spectrophotometry as a non-destructive in situ technique to evaluate the cleaning effectiveness. A biofilm composed by filamentous green algae and cyanobacteria developed on a granitic building located in NW Iberian Peninsula was removed using different cleaners commonly used by professionals i...
Article
Desalination of rocks used in monuments is a common strategy to reduce the possibility of deterioration by soluble salt crystallization processes. In the last years, some laboratory studies have demonstrated that the application of electrokinetic techniques allow to achieve higher desalination effectiveness, overcoming most limitations of the tradi...
Article
Marking petroglyphs with chalk is a common practice to enhance them for documentation and reproduction. Although this procedure has started to be less frequently used, there is no knowledge about the interaction between the rock engravings nor about the effectiveness achieved by the common cleaning procedures of such markers considering the chalk e...
Article
Full-text available
Laser cleaning of stones is a well-established technique in conservation of Cultural Heritage. In case of polymineralic granular rocks like granite, the tuning of the laser parameters for safe cleaning becomes a demanding task due to the differential response of the constituent minerals to laser irradiation. In this sense, a compromise solution mus...
Article
Consolidation is considered one of the major restoration treatments applied on cultural heritage. This kind of treatment is focused on to preserve the external weathered layers of stone reducing their degradation caused by external alteration agents (mainly water and soluble salts). However the consolidation using commercial products have some limi...
Article
The aim of this study is the exploration of the suitability of two different statistical approaches (vectorial and functional analyses), which go beyond a purely descriptive statistics, in order to identify trends and similarities in colour changes of several tempera mock-ups paints during thirteen months. The samples were subjected under an outdoo...
Article
Prehistoric rock art sites are endangered despite conservation efforts. The lack of scientific documentation regarding weathering agents affecting rock art and the absence of specific diagnostic protocols hinder the development of conservation strategies. The aim of this research was to investigate active deterioration processes in a granite petrog...
Article
Soluble salts are one of the most important factors of deterioration of cultural heritage, being desalination by different methods the most common intervention to minimize their harmful effects. Presented in this article are the results of an evaluation of the effectiveness of two desalination methods: immersion baths and application of poultices,...
Article
Soluble salts are considered one of the main deterioration factors of porous building materials such as rocks, bricks or granites. The desalination treatments currently used in order to mitigate this alteration process are usually applied directly on the affected areas, which have often a low degree of cohesion precisely due to the deteriorating ef...
Article
Full-text available
The progress of the laser cleaning of two graffiti paints on coarse-grained granite was in situ followed up by the hyperspectral imaging technique, through the calculation of a quantitative index based on a linear spectral mixture analysis model, which provided an estimation of the cleaning level attained along the process. The laser used was a nan...
Article
Most of the Cultural Heritage built in NW Iberian Peninsula is made of granite which exposition to the environment leads to the formation of deposits and coatings, mainly two types: biological colonization and sulphated black crusts. Nowadays, another form of alteration derives from graffiti paints when these are applied as an act of vandalism.A de...
Article
Nowadays, graffiti paints are one of the most common human interventions on monuments and historic façades with damaging results. It is an aesthetic problem but also a serious threat to the conservation of built heritage. The aim of this article is to evaluate the suitability of a hyperspectral imaging technique as a non-destructive tool to determi...
Article
A study of the cleaning effectiveness of sulphated black crust developed on granite is presented. The sulphated black crust, previously characterized, was subjected to a cleaning by 1) a mechanical procedure –Hydrogommage– based on micro-sandblasting, 2) chemical procedures based on the application of poultices made on different mixes of thickening...
Article
Full-text available
The aim of this paper was to evaluate the effectiveness of the laser cleaning of a complex biogenic patina, a crustose lichen, by means of hyperspectral imaging techniques. Samples of a Hercynian granite from NW Spain colonised by an endolithic crustose lichen (Pertusaria amara) were collected and cleaned following three procedures: a scalpel, the...
Patent
https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2017103298 The invention relates to a method for extracting ions present in a porous material, which allows the counteraction of all of the harmful effects inherent in electrochemical techniques, such as: 1) extreme changes in pH generated in the vicinity of the porous medium to be treated;...
Article
This paper reports the results from the comparative evaluation of the global cleaning effectiveness of four graffiti colours (red, blue, black and silver) applied on two granites with different textures and compositions. A conventional mechanical method and several chemical products were evaluated. Additionally, it was evaluated the cleaning based...
Article
In this paper, it is presented a study of the application of the hyperspectral imaging technique in order to non-destructively evaluate the laser cleaning of the biogenic patina and the sulphated black crust developed on a fine-grained granite used in the construction of Cultural Heritage in NW Spain. The grained polymineral texture of the granite...
Article
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...
Conference Paper
In this work it is presented a study about the ability of multispectral techniques for evaluating in situ, nondestructively, the progress of laser removal of crusts and paints in granitic rocks. For this purpose, granites with different characteristics were cleaned by the third harmonic of a Nd:YVO4 laser, and a multispectral camera was used to mon...
Article
We describe the results of sulphur and oxygen isotope analyses used to identify sources of the gypsum present in black crusts that grow on the granite of historical buildings. The crusts were sampled at various locations in and near the city of Vigo (NW Spain) and were analysed for their sulphur content and δ34S and δ18O isotope ratios. Sampled cru...
Conference Paper
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...
Conference Paper
n the framework of the investigation of the effectiveness and durability of different commercial products as protectors against oxidation of metal sulfides in roofing slate, we present the analysis of the interaction degree between pyrite and five protective products (Tegosivin® 100-HL-HL, Tegosivin HE328®- HE, Triethyltetramine, Oxino® and Rewopol...
Conference Paper
Slate is a valuable ornamental rock, specially used as roofing material due to its aesthetic and waterproofing properties. Among the characteristics that define the technical and aesthetic quality of slate, the presence of metallic inclusions is one of the most important because the oxidation of these inclusions may reduce water resistance and caus...
Chapter
In the framework of the investigation of the effectiveness and durability of different commercial products as protectors against oxidation of metal sulfides in roofing slate, we present the analysis of the interaction degree between pyrite and five protective products (Tegosivin® 100-HL-HL, Tegosivin HE328®-HE, Triethyltetramine, Oxino® and Rewopol...
Article
Full-text available
Sulphated black crust is a common form of deterioration affecting stone used in monuments, usually occurs in contaminated atmospheres or urban environments. Its origin and cleaning have been studied extensively, for decades, in the case of carbonate rocks. Recent studies show that this form of alteration also affects granites. Scientific research o...
Article
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...
Article
Granite has been widely used as a structural and ornamental element in public works and buildings. In damp climates it is almost permanently humid and its exterior surfaces are consequently biologically colonized and blackened We describe a comparative analysis of the performance of two different laser sources in removing biological crusts from gra...
Article
Full-text available
This paper presents the evaluation of the efficacy of the removal of biological crust from ornamental granites. The removal was made applying different procedures and the efficiency was evaluated by means of optic and scanning electron microscopy (SEM), Fourier Transformed Infrared spectrometry (FTIR) and colour measures (CIE-L*a*b* colour spaces)....
Book
Full-text available
A preliminary approach to the discovery of the first paints and engravings assigned to the Paleolithic in a cave of Galicia (Northwest Iberia).