Paula López-Arce

• PhD
• Lecturer in Construction at University of Westminster

Carbonation of Ca(OH)2 nanoparticles and consolidation of limestone are accelerated by high humidity and a yeast fermentation system that supplies a saturated atmosphere on CO2, H2O vapor and ethanol during 28 days. Nanoparticles were analyzed by X-ray diffraction and differential thermal analyses with thermogravimetry. Spectrophotometry, scanning...

Insufficient ventilation is one of the main factors leading to damp and mould in residential buildings. One low-cost method to improve these moisture-related issues is positive input ventilation (PIV) but research data on performance is scarce in the literature. This paper presents a bibliographical review together with a case study based on monito...

An innovative method known as Building Moisture Index (BMI) has been applied in hundreds of properties suffering of surface condensation and mould growth in order to quantify and rectify indoor atmospheric moisture imbalance. BMI system is a protocol, a method and a computer program that processes, assesses and reports environmental data in a fast,...

RESUMEN.‐ El presente catálogo recoge imágenes en color escaneadas directamente de 329 placas de tamaños iguales de 21x21 cm de la colección de mármoles históricos de España patrocinada por los reyes de España desde 1700 a 1808 perteneciente a la Colección de Geología del Museo Nacional de Ciencias Naturales de Madrid (MNCN, CSIC). Se incluyen las...

The occurrence of surface condensation and mould can lead to concerns of poor indoor air quality and adverse health implications of occupants. Remedial actions require identification of the root causes, but this can be challenging even for experts. The focus of the research is the development of a diagnostic tool that helps to streamline root cause...

Chert tools from Galería and Gran Dolina Caves, located in the Sierra de Atapuerca site complex (Burgos, Spain), were characterized (macro-visual inspection, mineralogical phases, degree of crystallinity, soluble salts, surface morphology and optical surface roughness) and compared to chert samples collected from the surrounding Atapuerca mountain...

Thallium (Tl) is a hazardous trace metal that can harm human and environmental health. Tl pollution can result from the mining and smelting of Tl-bearing minerals, but also the natural weathering of Tl-bearing sulfide minerals may induce Tl release to the environment. In this study, hydrothermal deposits hosted in dolostone rocks sited along fossil...

Increased occupancy rates, inappropriate ventilation and intermittent heating regimes in dwellings can result in excessive atmospheric moisture levels, potentially leading to mould growth and lower indoor air quality. Identifying the causes associated to mould growth and taking correct remedial actions can be essential in reducing the prevalence of...

Increased occupancy rates, inappropriate ventilation and intermittent heating regimes in dwellings can result in excessive atmospheric moisture levels, potentially leading to mould growth and lower indoor air quality. Identifying the causes associated to mould growth and taking correct remedial actions can be essential in reducing the prevalence of...

The Spanish Fortress of Bizerte in Tunisia shows differential erosion patterns on the rock ashlars used in the construction of its main façade (sixteenth century) exposed to marine aerosol action and several restoration works. In order to determine the origin of this erosion and the degree of stone decay, a combination of microdestructive and nonde...

In this chapter the degradation mechanisms of stone cultural heritage materials used for construction of monuments, sculptures, building materials, or working tools and artifacts are described. It starts by presenting the weathering causes due to the stone intrinsic factors, i.e., those parts inherent to the material, such as chemical composition a...

Long-Term Performance and Durability of Masonry Structures: Degradation Mechanisms, Health Monitoring and Service Life Design focuses on the long-term performance of masonry and historical structures. The book covers a wide range of related topics, including degradation mechanisms in different masonry types, structural health monitoring techniques,...

Calcarenite stone samples from a historic building (Bizerte, Tunisia) were collected and treated under different environmental conditions with several consolidating products: alkoxysilane (ethyl silicate), a surfactant-templated novel sol–gel, Ca(OH)2, and SiO2 nanoparticles. These were subjected to marine aerosol accelerated aging cycles and studi...

Calcarenite stone samples from a historic building (Bizerte, Tunisia) were collected and treated under different environmental conditions with several consolidating products: alkoxysilane (ethyl silicate), a surfactant-templated novel sol-gel, Ca(OH) 2 , and SiO 2 nanoparticles. These were subjected to marine aerosol accelerated aging cycles and st...

Hydrothermal pyrite is an important source of thallium (Tl) but this rare element can be also detected in the secondary iron goethite-lepidocrocite and jarosite ores, associated to hydrothermal kerogen, manganese oxides, accessorial potassium minerals and tiny Tl-bearing clusters shielded in quartz masses. We studied Tl-bearing samples collected fr...

Optical measurements of microscale crystals suggest a new model for the luminescence centers associated with classic spectral cathodoluminescence emissions, which has implications for their material and photonic properties. In particular, manganese impurities in aluminosilicate lattices are commonly associated with ultraviolet and green (UV&G) spec...

In the frame of a research project on microscopic distribution and speciation of geogenic thallium (Tl) from contaminated mine soils, Tl-bearing pyrite ore samples from Riotinto mining district (Huelva, SW Spain) were experimentally fired to simulate a roasting process. Concentration and volatility behavior of Tl and other toxic heavy metals was de...

Monuments and historical buildings of Bizerte show a disturbing state of degradation. In order to propose a compatible materials for the restauration works such as stone of substitution and restauration mortars, a geological context was analysed with the objectif to localize historical quarries accompanied by a sedimentological study to identify th...

he Spanish Fortress of Bizerte in Tunisia shows differential erosion patterns on the rock ashlars used in the construction of its main façade (sixteenth century) exposed to marine aerosol action and several restoration works. In order to determine the origin of this erosion and the degree of stone decay, a combination of microdestructive and nondes...

The increase of durability to slowdown damage of chert artifacts is assessed after their treatment with traditional consolidating products (acrylic resin and ethyl silicate) and new products based on SiO2 and Ca(OH)2 nanoparticles. The stability of the treatments is analyzed submitting the samples to wetting-drying cycles and UV light exposure acce...

The physico-chemical compatibility of the most frequently used commercial stone-repair mortars applied to repair surface damage of a common limestone (Euville stone) employed in the basements of historic buildings from Paris was assessed. The characterization of anhydrous raw mortar materials, of stone and mortar samples collected from these buildi...

One hundred and sixty five years ago, Henry Clifton Sorby developed a revolutionary technique to prepare thin and polished sections of rocks and minerals to be observed by transmission and reflectance in the optical polarized light microscopes. Nowadays, Sorby’s methods are still employed for near all inorganic materials with scarce modifications....

Stone-mortar specimens manufactured with limestone and commercial stone-repair hydraulic mortars have been exposed to accelerated ageing tests, salt crystallisation (mixture of sodium chloride, sodium sulphate, calcium sulphate and potassium nitrate) and acid vapours exposure (sulphurous and nitric acid) besides, their corresponding control specime...

The most frequently used restoration mortars used for stone repair of historic buildings from the city of Paris (France) have been selected to study their durability and interaction with one of the most common natural stone used in the basements of these buildings. Three commercial, ready to used, mixtures of natural and hydraulic limes (NHL, HL) m...

The influence of relative humidity (RH) has been determined in SiO2colloidal nanoparticles, to studytheir efficacy as a consolidating product by means of the physical changes in the hydric and mechanicalproperties produced in a siliceous-carbonate stone from a historic building (XVI century) with signs ofdegradation. Therefore, diverse analytical t...

This paper analyses the efficacy of dispersions of nanoparticles of calcium hydroxide for consolidating lime mortars, according to three variables: the type of dispersion (3 consolidating compounds—CaLoSil�, Nanorestore� and Merck�—with different-sized calcium hydroxide particles); the concentration of the dispersion (5 and 25 g/L of Ca(OH)2 in iso...

Stone materials used in the construction of the Spanish Fortress of Bizerte (Tunisia), show a high degree of alteration. Samples of these rocks, calcarenites, were collected and treated with different consolidants. Then, they were subsequently subjected to salt spray test with ventilation, in order to test the effectiveness of the products under th...

Stone materials used in the construction of the Spanish Fortress of Bizerte (Tunisia), show a high degree of alteration. Samples of these rocks, calcarenites, were collected and treated with different consolidants. Then, they were subsequently subjected to salt spray test with ventilation, in order to test the effectiveness of the products under th...

The consolidation effects of portlandite ðCaOHÞ 2 nanoparticles have been determined in carbonate stones (dolostone), typically used in historical buildings from Madrid, Spain, just after 20 days consolidation at 20°C under a dry [33% relative humidity (RH)] and a humid environment (75% RH) and after 18 months under room temperature and humidity co...

The consolidation effectiveness and changes in the petrophysical properties of dolostones, typically used in historical buildings, are studied after one year of their consolidation with a Ca(OH) 2 nanoparticles based product. Dolostone samples were subjected to different accelerated aging tests to simulate the most common outdoor heritage deteriora...

Non-desalinated and desalinated fragments of Iberian, Italic and Tarraconensian amphorae sherds, found in different underwater marine environments, were compared to determine the decay caused by salt crystallization. Polarizing light and fluorescence optical microscopy, scanning electron microscopy coupled to energy dispersive X-ray spectroscopy, X...

The purpose of the research is to study the influence of environmental conditions in the consolidation treatment of typical Mediterranean calcarenite stone using different organosilicic and nano inorganic consolidating products. The on-site study was performed in the Spanish Fort of Bizerte, a major bastion of the 16th century, in Tunisia. The monu...

This study is focuses on the characterisation of the pastes and enamels constituents of the decorative ceramics, cladding ceramics and mosaic tiles, covering the façades and the central garden fountain of the Former Workers Hospital of Maudes at Madrid, Spain. The structural bricks of the inner fabric walls and those used at the courtyards are also...

The defects in calcium carbonate polymorphs forming when portlandite nanocrystals are exposed to high relative humidity were directly observed and analyzed under high-resolution transmission electron microscopy. The findings provided significant insight into aragonite to calcite phase transformation mechanisms. The aragonite lattice exhibited stack...

Salt crystallization is one of the most frequent causes of building materials alteration and it has been recognized as one of the principal responsible for irreversible damage on cultural heritage. However, despite of being a major problem for the heritage conservation and having developed many methods to avoid or minimize damage, the removal of sa...

Petrophysical techniques commonly used for material characterization are applied for the first time to speleothem samples to investigate the porosity and hydric behavior of calcite stalagmites used in paleoclimatology. These techniques allow the determination of the stalagmites' potential to undergo diagenetic transformations when substantial chang...

Outdoor stone heritage is prone to decay due to its direct exposure to weathering agents such us thermal shock caused by isolation processes, salt crystallization phenomena, atmospheric pollutants effects on stone surfaces, freezing and thawing cycles or biodeterioration o decay provoked by biogenic activity. These damages use to affect the surface...

The construction of the Cistercian Monastery began at 1180, in an initial Late Romanesque style in which the Church was erected; later on, in 1258, the church underwent a severe fire, only the apse stood standing. The church was reconstructed at the end of the 13th century in Mudejar style. Gothic style was used later on, in the 16th century, for t...

Calcium hydroxide (also known as lime) is one of the oldest products used in construction, mainly as a binder in mortars (joint mortars, renderings, wall fillings, etc), in mural paintings, as a consolidant product, together with other materials such as rammed-earth. . In Conservation Science it can be used to restore the cohesion loss by filling t...

Water and moisture are some of the main decay agents of building stone and, in general of any stone structure. Several non-invasive methods are used to quantify moisture in building stone, many of them based on the fact that moist stone presents different electrical properties than dry stone. This is the case of resistance-based sensing equipment,...

Non-destructive techniques (NDT): X-Ray Microtomography (CT scan) and Nuclear Magnetic Relaxometry and Magnetic Resonance Imaging (NMR-MRI) have been used to obtain a three dimensional reconstruction of the inner part of a speleothem, since one of the main concerns when working with speleothems is the common need of using destructive techniques for...

Zircon (ZrSiO4) is a mineral widely employed in the production of refractories, pigments, glazed tiles etc. The high radioactive content of this mineral stems from the presence of natural alpha emitters as U and Th. The radioactive activity of the 238U, 235U and 234U, 228Th, 230Th and 232Th radionuclides was measured by alpha spectrometry after iso...

This article reports on a study of Iberian, Italic and Tarraconensian amphorae sherds found in different underwater marine environments. Non-desalinated fragments were compared to fragments desalinated using the procedure normally applied to underwater archaeological objects to study the efficacy of the method and determine both the state of conser...

The advantages of using portable Raman spectrometer equipment, such as avoiding sampling and providing a higher number of results, are contrasted with some of its shortfalls that make other analytical techniques necessary to characterize salt efflorescences on historic buildings. In-situ analyses of salt efflorescences were carried out with a porta...

The effect of high relative humidity (90% and 75% RH) on phase transformation and stability of CaCO3 polymorphs has been studied based on the structural and morphological changes from a colloidal solution based on Ca(OH)2 nanocrystals. Carbonation process has been confirmed indicating differences in nucleation and stability of CaCO3 polymorphs as a...

El Paular Monastery (eleventh century) is one of the most important Carthusian monasteries in Spain and is highly affected by crystallisation of Mg-sulphates, together with chlorides and nitrates. Urgent remediation of the decay process is needed to guarantee the stability of the building materials from the cloister and to make their hallways suita...

The thermal stability of sodium oxalate (Na2C2O4) has been analyzed in the range of room temperature and 900°C by different techniques. All of them, namely (i) environmental scanning electron microscopy (ESEM); (ii) differential-thermal analysis with simultaneous thermo-gravimetry (DTA–TG); (iii) temperature programmed decomposition mass spectromet...

In this article, the results of a treatment applied to dolomitic stones using an isopropyl colloidal solution based on calcium hydroxide nanoparticles with a concentration of 2.0g/l are presented. The consolidation process in the stone has been checked before and after 28 days of exposure to 75% relative humidity. Morphologic and structural studies...

Albite sodium feldspar is studied by thermoluminescent methods using the blue region of the spectra (circa 400nm) and the possible uses as a dosimeter are explored. The light emission of the spectra bands of natural and irradiated albite under X and gamma rays are determined using automated RISØ thermoluminescence equipment. Albite is a potential m...

A new designed stainless steel door, which holds cooling fluids, permits connect a set of sensors (DTA, RH, RL) to a traditional diffractometer and record sets of isothermal and non-isothermal diffraction profiles (in a range of 17ºC-200ºC) allowing dehydration and retrenchment effects of an historical claystone from Toledo to be studied. In additi...

A consolidating product based on nanoparticles of slaked lime (Ca(OH)2) dispersed in isopropyl alcohol was exposed under different relative humidities (RH), 33%, 54%, 75% and 90% during 7, 14, 21 and 28 days. The characterization of the calcium hydroxide nanoparticles and the formed calcium carbonate polymorphs have been performed by Micro Raman sp...

A study of the stability of calcium carbonate polymorphs formed as a result of the carbonation process from an alcoholic colloidal solution of nanocrystals of Ca(OH)2 in low relative humidity (RH) conditions (33% and 54% RH) is presented in this research. The crystalline behavior, the time dependence of nucleation and the phases’ transformations as...

Nanoscience deals with a large diversity of research fields and applications due to in the nanomaterials most of their properties are modified or improved by the effect of the reduction in size. One of the main aspects in conservation of cultural heritage properties is to minimize or repair the decay of stone materials as a result of their exposure...

El objetivo principal de esta investigación es determinar las características estéticas (color y dimensiones), composicionales (mineralógica y temperatura de cocción original) y tecnológicas (propiedades físicas, hídricas y mecánicas) de ladrillos pertenecientes a edificios históricos de la ciudad de Toledo. El estudio se ha orientado hacia la sele...

For hundreds of years, two types of granite (Zarzalejo and Alpedrete) from the Madrid region, Spain, have been extensively used as building stones. Fresh specimens of both stone types have been sampled from their respective quarries and subjected to sodium sulphate salt crystallization test (SCT). The resulting physical and chemical weathering patt...

Slaked lime (Ca(OH)2) nanoparticles were exposed at 33% and 75% relative humidity (RH) to consolidate dolostone samples used in historical buildings. Non-destructive techniques (NDT) were applied to determine the chemical, morphological, physical and hydric properties of the stone samples, before and after 20days treatment. Morphological and minera...

Since its abandonment 185 years ago, the XII century Santa Maria de Bonaval Monastery located in Guadalajara (Spain) has suffered significant deterioration: first the roof was lost, followed by partial collapse of the walls, moisture infiltration and extensive loss of stone surfaces due to salt weathering. This case study is a clear example of the...

Magnesium sulfate salts often result from the combination of incompatible construction materials that, when combined with a source of moisture, react to form soluble salts often leading to significant damage by flaking of the stone. Several laboratory experiments were performed to reproduce surface flaking on limestone and to evaluate the effects o...

The effect of thermal annealing on charoite, K(5) Ca(8) (Si(6)O(15)) (Si(2)O(7)) (Si(4)O(9)) (OH)center dot 3H(2)O, have been studied by X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetry (TG) and thermoluminescence (TL). The chemical composition, established by electron-probe micro-analysis (EPMA), indicates significant...

The City of Adelaide suffers from rapid damage to historic building materials due to salts, rising damp, and damp-proof course failures. Adelaide City Council has partially funded repairs to over 400 buildings in the past 15years. To begin to examine the scope of this problem and the effectiveness of various treatments, 24 historic buildings in Ade...

Magnesium sulfate salts often result from the combination of incompatible construction materials, such as stone or mortar with high magnesium content and sulfates from adjacent mortars or polluted air. When combined with a source of moisture, these materials react to form soluble salts, often leading to significant damage by flaking of the stone, a...

X-ray diffraction measurements, during halogen lamp illumination to simulate sunlight, (TXRD) show a phase transition from variscite (AlPO4·H2O) Messbach to variscite Lucin and a loss of the dark green colour. The differential-thermal and thermo-gravimetric (DTA-TG) analyses and thermoluminescence (TL) peaks all depict this first-order phase transi...

19 pages, 4 figures.-- To be published in Canadian Mineralogist. The effect of thermal annealing of charoite silicate K5 Ca8 (Si6O15) (Si2O7) (Si4O9) (OH)·3H2O have been studied by X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetry (TG) and thermoluminescence (TL). The chemical composition, analysed under electron probe...

Cabrera (Madrid) low-Mg calcites exhibit: (i) an unusual twofold elevation in X-ray diffraction pattern intensity; (ii) a 60-fold elevation of luminescence emission, compared to six common natural calcites selected for comparison purposes; (iii) a natural relatively high radiation level of circa 200 nSvh(-1) not detected in 1300 other calcites from...

Pectolite (NaCa2Si3O8(OH)) is an inosilicate of hydrothermal origin hosted in Cretaceous basalt with calcite and iron oxides and is almost always associated with zeolites. The emission of this silicate was studied by laser-induced fluorescence (LIF) and thermal stimulated luminescence (TL). The fluorescence spectra of different areas of the sample...

The behavior and development of thenardite (anhydrous sodium sulfate) from mirabilite (sodium sulfate decahydrate) under the Environmental Scanning Electron Microscope (ESEM) during humidity clycling (50%-100%) was observed. After 7 cycles a microcrystalline porous structure of thenardite was formed with an increased surface area and volume compare...

PDF of Presentation Slides. Supplement to the article: Lopez-Arce, Paula & Doehne, Eric 2006, Kinetics of sodium sulphate efflorescence as observed by humidity cycling with ESEM. Proceedings of the Heritage, Weathering & Conservation Conference, Madrid, Spain, June 2006, HWC. 220-230.

Presentation - PDF of 15 slides.-- Communication presented in: Heritage, Weathering & Conservation Conference (Madrid, June 21-24, 2006). [Background] Fluctuations of atmospheric conditions cause dehydration and hydration of hygroscopic salts, leading to expansion and contraction that results in fatigue stress of the porous material (Overmiller, 19...

9 pages (final publisher version), 28 pages, 6 figures (attached post-print version).-- This work is based in part on the thesis submitted by P. López-Arce for the Ph.D. in Geology, Complutense University of Madrid, Spain, 2004. The physicomechanical properties of historic bricks in Toledo (Spain) that have undergone a time-dependent self-healing b...

The aim of this work was to determine the type of weathering suffered by bricks belonging to a number of historic buildings in Toledo, Spain. These bricks had been exposed to either aerial or burial environments, came from different places in the selected buildings, were of different mineralogical composition, and had been fired at different temper...

The gold outcrops employed by the ancient kingdom of Tartessos, settled in the SW of the Iberian Peninsula from ca. 10th to the 6th century BC, for the Aliseda treasure manufacture, has been discovered. This paper reports on the finding of collected gold nuggets, more than 80 units up to 218 g, in an ancient mining area located in Casas de Pedro (E...

The present study deals with energy savings in brick manufacture. Laboratory driven experiments with additions of Greek lignite (low rank coal) and Spanish claystone have been performed. In particular, co-firing of clay raw material with organic additives is performed in order to minimise the fuel consumption while maintaining the good quality of t...

The kinetic parameterisation of lime mortar carbonation is a useful technique for understanding ancient building methods and the long-lived physical-chemical stability of roman monuments. Portlandite (Ca(OH) 2 ) binders harden in the air on contact with atmospheric CO 2 , producing CaCO 3 . Water evaporation and the presence of silicate aggregates...

The kinetic parameterisation of lime mortar carbonation is a useful technique for understanding ancient building methods and the long-lived physical-chemical stability of roman monuments. Portlandite (Ca(OH)₂) binders harden in the air on contact with atmospheric CO₂, producing CaCO₃. Water evaporation and the prese...

The spectral properties of Na2SO4 have been studied by means of infrared stimulated luminescence (IRSL), thermoluminescence (TL) and radioluminescence (RL) in the range of 200-800 nm. The observed changes in the RL emission spectra after an annealing treatment (400 degrees C for 1 h) could be linked to thermal phase transformations and alkali self-...

Albite sodium feldspar is studied by\ thermoluminescent methods using the blue region of the spectra (circa 400nm) and the possible uses as a dosimeter are explored. The light emission of the spectra bands of natural and irradiated albite under X and gamma rays are determined using automated RISO thermoluminescence equipment. Albite is a potential...

A new designed stainless steel door, which holds cooling fluids, permits connect a set of sensors (DTA, RH, RL) to a traditional diffractometer and record sets of isothermal and non-isothermal diffraction profiles (in a range of 17°C-200°C) allowing dehydration and retrenchment effects of an historical claystone from Toledo to be studied. In additi...

Zircon (ZrSiO4) is a mineral widely employed in the production of refractories, pigments, glazed tiles etc. The high radioactive content of this mineral stems from the presence of natural alpha emitters as U and Th. The radioactive activity of the 238U, 235U and 234U, 228Th, 230Th and 232Th radionuclides was measured by alpha spectrometry after iso...

Romans, Jews, Arabs and Christians built the ancient city of Toledo (Spain) with bricks as the main construction material. Manganese micro-nodules (circa 2 microm in diameter) have grown under the external bio-film surface of the bricks. Recent anthropogenic activities such as industrial emissions, foundries, or traffic and housing pollution have f...

10 pages (final publisher version), 23 pages (attached post-print version). Two different types of ancient bricks (12th to 14th centuries) collected from historical buildings of Toledo (Spain) were characterised by optical microscopy, scanning electron microscopy/energy-dispersive X-ray spectrometers (SEM/EDS), electron probe microanalysis (EM), X-...

Petrology has turned into a fundamental discipline for the step forward in research and conservation of architectural and monumental heritage, in the causes generating its decay, as well as in the most adequate conservation and protection techniques according to materials´ petrophysical characteristics and the type of environment in which materials...