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External Thermal Insulation Composite Systems (ETICS) have been extensively used for either new constructions or building facades retrofitting in the last decades. These systems can provide improved thermal performance to the building envelope. However, their long-term durability remains a pervasive concern, with some systems presenting relevant anomalies after few years from their application. The durability assessment of ETICS is defined by the EAD 040083-00-0404 guideline, which stated an accelerated ageing procedure based on the hygrothermal and freeze-thaw behaviour. Nevertheless, further important environmental urban conditions, such as UV radiation and atmospheric pollutants, as well as bio-susceptibility, are not envisaged in the guideline. This paper presents the results of an experimental campaign with the aim of evaluating the durability of the rendering system of several commercially available ETICS exposed to an innovative accelerated ageing procedure, which consists of hygrothermal cycles, UV radiation and air pollutants (SO₂) exposure. Physical and chemical-morphological tests were carried out prior and after each ageing cycle in order to evaluate the durability of ETICS. Biological susceptibility to moulds was also assessed. The experimental results showed that both surface hardness and surface gloss decreased after the combined effect of the hygrothermal, UV, and SO₂ ageing cycles, whereas an increase of surface roughness was observed. Substantial colour change for all systems after the ageing procedure was observed, confirming aesthetic alteration. Traces of biological growth were detected on the systems after ageing and the contact angle decreased after the hygrothermal cycles, indicating a lower surface hydrophobicity of the systems. The authors acknowledge the support given by the Portuguese Foundation for Science and Technology (FCT) within the research project WGB_Shield (PTDC/ECI-EGC/30681/2017). J.L. Parracha acknowledges FCT for the Ph.D. scholarship (2020.05180.BD). The authors also acknowledge CIN, Saint-Gobain and Secil Martingança for the material supply, Dr. Pedro Nolasco from CQE/IST for the static contact angle tests and Marta Duarte from UPB/LNEC for the fungal tests. info:eu-repo/semantics/publishedVersion

PTDC/ECI-EGC/30681/2017 Os sistemas de isolamento térmico pelo exterior do tipo ETICS são uma solução cada vez mais frequente na reabilitação de fachadas de edifícios em Portugal, devido não só a imposições legais, cada vez mais exigentes no que diz respeito à eficiência energética dos edifícios, mas também pelas vantagens que apresentam face a outras soluções. Ainda assim, estes sistemas compósitos possuem algumas desvantagens que continuam a condicionar o seu bom funcionamento e um estudo mais abrangente e focado na durabilidade ao longo do tempo do ETICS continua a ser necessário, devendo procurar minimizar-se anomalias na superfície e otimizar os sistemas de revestimento, evitando que o desempenho térmico da camada isolante seja afetado. Neste artigo, apresentam-se os primeiros resultados de um estudo de análise do desempenho à água de 12 soluções diferentes de ETICS, através de absorção capilar e secagem, procurando avaliar-se a capacidade de proteção à água dos acabamentos das diferentes soluções e o possível impacto de deficiências de impermeabilização na condutibilidade térmica do isolante. Todas as soluções cumprem o requisito do ETAG 004 que refere uma absorção capilar após 1 h de ensaio inferior a 1 kg/m2. Os resultados de secagem estão em concordância com os obtidos para a absorção de água por capilaridade: soluções que absorvem maior quantidade de água e mais rapidamente, também acabam por secar mais rapidamente. Ainda assim, a condutibilidade térmica dos isolantes (λ) é afetada pelo seu teor de água (Ψ), registando-se um aumento de λ com o aumento de Ψ. No entanto, este aumento não é significativo para a maioria dos isolantes, com exceção da lã mineral, onde λ aumenta muito rapidamente com o aumento de Ψ. authorsversion published

ENCORE 2020 – 4º Encontro de Conservação e Reabilitação de Edifícios, Lisboa, LNEC, 3-6 novembro 2020. Conservar e Reabilitar monumentos, edifícios e espaços são oportunidades únicas para fomentar a sustentabilidade dos territórios, constituindo-se o ENCORE 2020 - 4º Encontro de Conservação e Reabilitação de Edifícios numa ocasião ímpar para discutir os desafios da transformação no espaço construído: otimizar recursos, reutilizar materiais, melhorar a eficiência energética, repensar as centralidades urbanas, promover a resiliência. O presente documento junta os textos das comunicações apresentadas sobre a multiplicidade de aspetos que se entrecruzam no âmbito da intervenção no património construído, identificando, de forma multidisciplinar e sinergética, os desafios e os caminhos para melhor Conservar e Reabilitar. info:eu-repo/semantics/publishedVersion

9th International Masonry Conference 2014, 7-9 July, Universidade do Minho, Guimarães A common degradation phenomenon in historical renders is the cohesion loss of the binder:aggregate system, which is often linked to the presence of soluble salts. Cohesion is recovered through the application of consolidant products, being inorganics preferred due to their compatibility and durability. The aesthetic function can be restored by chromatic reintegration. The aim of this paper is the assessment of the durability of consolidation and chromatic reintegration treatments applied on renders when exposed to marine environment. Mortar specimens with a simulated loss of cohesion were consolidated with commercial nanolimes,which were considered due to their stability and compatibility. Their combined application with ethyl silicate guarantees some benefits. Chromatic reintegration treatments were obtained by mixing pigments in the consolidant products. After treatments, dissolution-crystallization cycles were performed with a sodium chloride solution. Consolidation effects were monitored. Physical characterization was performed on specimens before and after contamination and the results were discussed.

The surface consolidation of historical renders, directed to restore cohesion and stability, is based on the use of materials with aggregating properties. This operation is usually achieved with the use of inorganic or mineral consolidants, which are preferred to organic ones, due to the better compatibility and durability. Based on the results of previous studies, two mineral-compatible products were selected: a commercial dispersion of calcium hydroxide nanoparticles in propanol and a calcium-silicate product, consisting of a limewater dispersion of ethyl silicate. The consolidation products were applied to mortar specimens in order to assess their efficacy by determining their microstructural and physical-mechanical properties, before and after the consolidation treatment. Microstructural (optical and SEM microscopy) and chemical analyses of the consolidation products and of the consolidated samples were performed. The physical-mechanical analyses, i.e., the superficial hardness, is reported too. Utrjevanje površine zgodovinskih ometov z vidika ohranjanja kohezije in stabilnosti temelji na uporabi materialov z vezivno sposobnostjo. To se navadno doseže z uporabo neorganskih ali mineralnih utrjevalcev, ki so v prednosti pred organskimi zaradi boljše skladnosti in zdržljivosti. Na podlagi predhodnih študij sta bili izbrani dve vezivi: komercialna disperzija delcev kalcijevega hidroksida v propanolu in proizvod na osnovi kalcijevega silikata, ki vsebuje apnovico, dispergirano v etil silikatu. Namen uporabe vzorcev veziv na vzorcih malte je bil ugotoviti njihovo učinkovitost z določitvijo mikrostrukture in fizikalno-mehanskih lastnosti, pred obdelavo z vezivom in po njej. Izvršene so bile raziskave mikrostrukture (svetlobna in SEM-mikroskopija), kemijska analiza vzorcev veziv in vzorcev po utrjevanju, fizikalno-mehanski preizkusi, poročamo pa tudi o trdoti površine.

4º Congresso Nacional CONSTRUÇÃO 2012, Coimbra, Portugal, 18-20 Dezembro 2012 A consolidação de revestimentos antigos com perda de coesão acontece, geralmente, quando os mesmos apresentam um valor artístico elevado. Esta importante fase de intervenção conservativa deve ser levada a cabo através da utilização de produtos compatíveis com o revestimento; os produtos consolidantes comummemente aplicados são de natureza orgânica ou inorgânica. Os produtos orgânicos, à base de resinas acrílicas, vinílicas ou silicónicas, são incompatíveis com os suportes antigos; os consolidantes mais compatíveis encontram-se no grupo dos inorgânicos, onde se inserem a água de cal e o silicato de etilo, que também se caracterizam pela maior durabilidade e reversibilidade. Neste estudo, foram utilizados produtos consolidantes à base de hidróxido de cálcio, metacaulino (uma pozolana artificial), água e pigmentos inorgânicos. De facto, a água de cal, composta essencialmente por hidróxido de cálcio, é um dos consolidantes mais antigos de que se tem conhecimento; a adição do metacaulino prende-se com o facto de conferir ao produto propriedades hidráulicas, aumentando a sua resistência mecânica e durabilidade; a adição dos pigmentos inorgânicos pretende avaliar a viabilidade da reintegração cromática e também verificar a sua influência na consolidação das argamassas. A água de cal é um meio fortemente alcalino, sendo os pigmentos inorgânicos os que apresentam melhor resistência e durabilidade quando incorporados nesta solução. Os produtos estudados foram aplicados em provetes de revestimento de argamassa de cal aérea; estes provetes foram feitos com uma quantidade reduzida de ligante, para simular um revestimento antigo com perda de coesão superficial. Realizaram-se ensaios de carácter mecânico, físico e cromático, que possibilitaram aferir a eficácia dos produtos consolidantes aplicados. Executou-se também um ensaio de envelhecimento artificial acelerado, para avaliar a variação das características das superfícies tratadas quando expostas a ciclos climáticos. Concluiu-se que os produtos consolidantes testados são compatíveis, eficazes e apresentam boa durabilidade, e ainda que a adição dos pigmentos pode prejudicar ligeiramente o incremento das resistências mecânicas conferido pela consolidação das argamassas. Este trabalho insere-se no projecto LIMECONTECH desenvolvido no LNEC, Universidade de Aveiro e Universidade Nova de Lisboa e financiado pela Fundação para a Ciência e a Tecnologia.

Nanolimes, i.e. dispersions of lime (Ca(OH)2)nanoparticles in alcohol, have been extensively investigated over the last two decades as consolidation products for calcareous substrates. The use of nanolimes for consolidation of mural paintings arises from the lack of effective and compatible consolidants for this type of substrates; the use of nanolimes was later extended also to limestone and lime-based mortars, as an alternative for silica-precursor consolidants (e.g. tetraethoxysilan - TEOS), which had shown to have a limited effectiveness and compatibility with calcareous substrates. Nanolime dispersions are characterized by a very small size of the lime particles, which should provide a proper penetration within the porous network of most building materials. In fact, a homogeneous and in-depth penetration of the consolidant is a crucial requirement when dealing with decayed stones and plasters/renders. The effectiveness of nanolime dispersions reported in literature appears controversial. Some authors observed a proper penetration and moderate consolidating action, whereas others report poor penetration, poor consolidation action and sometimes the formation of a white haze on the treated surface. There is no agreement concerning the factors affecting the transport and deposition of the lime nanoparticles within a porous network, and the causes of the observed drawbacks are not well understood. Therefore, the main research question is: Is nanolime a suitable alternative to silica-precursor consolidants (e.g. TEOS) for the consolidation of calcareous substrates? More specifically, the following research questions can be formulated: – How and up to which extent can the effectiveness and compatibility of nanolime be improved? How can deposition of nanolime in depth be improved and the appearance of a white haze on the surface avoided? – How can nanolime properties be fine-tuned to improve the effectiveness and compatibility of the treatment? – What is the effect of different application methods on the effectiveness of nanolime consolidation? This research investigates and elucidates the behaviour of nanolime products for consolidation of calcareous substrates. Based on the developed knowledge, it proposes and validates a methodology (including solvent modification and application protocol) for improving the consolidation effectiveness of nanolime dispersions, making these a suitable alternative for TEOS products. Firstly, an experimental campaign was carried out in order to understand the penetration and deposition of commercial nanolimes on coarse porous calcareous substrates (Maastricht limestone). The main cause of the poor nanolime deposition in-depth was identified in the back-transport of the nanoparticles towards the drying surface, as a consequence of the high volatility and low kinetic stability of the dispersions. The modification of the nanolime properties, through the optimization of the solvent, appears thus a feasible strategy to improve the in-depth deposition of the lime nanoparticles. New nanolimes were synthetized and dispersed in a selection of solvents conferring different stability and drying rate to the obtained nanolime dispersions. A conceptual model, correlating the properties (i.e. drying rate and kinetic stability) of nanolimes dispersed in different solvents, to the moisture transport behaviour of the substrates to be treated, was conceived. The model was experimentally validated on coarse porous (Maastricht) and fine-porous (Migné) limestones. Experimental results confirmed the predictions of the model that nanolimes dispersed in solvent with lower volatility and stability (e.g. water or butanol) have a good in-depth deposition within coarse porous networks. On the other hand, solvents with higher volatility and guaranteeing higher kinetic stability (e.g. ethanol or isopropanol) to the relative dispersions, should be preferred for substrates with fine porous networks. Fine-tuning the properties of the nanolime dispersion (by modification of the solvent) to the moisture transport behaviour of the substrate, is shown to be a successful strategy for improving in-depth deposition of lime nanoparticles. On the basis of the obtained results, the solvent mixture was further fine-tuned using ethanol-water mixtures. Results proved that ethanol-based nanolime, mixed with a minor amount of water (5%), can provide better nanoparticles in-depth deposition within coarse porous substrates (e.g. Maastricht limestone), when compared to dispersions in pure ethanol. The application procedure of nanolime dispersions was also studied and optimized, this step being a crucial aspect for a successful consolidation; nanolimes were applied both by capillary absorption (method commonly used for laboratory tests) or by nebulization (method widely used in situ) on a coarse porous limestone and a mortar. The research showed that results obtained by application through capillary absorption do not always correspond to those obtained by nebulization. The effectiveness and compatibility of nanolimes with improved properties and a fine-tuned application protocol were finally verified. Fresh and weathered Maastricht limestone, as well as lime-based mortars, were treated. Results showed that nanolime dispersions can guarantee an in-depth consolidation both in laboratory mortar specimens and weathered limestone, with only a moderate alteration of the total porosity and of the moisture transport properties of the investigated substrates. Therefore, nanolime dispersions, provided that they are properly formulated and applied, can be a suitable and compatible alternative to TEOS for the consolidation of coarse porous substrates. This dissertation contributes to define guidelines to support restorers and professionals in the choice and application of nanolime dispersions for consolidation of calcareous substrates., A+BE | Architecture and the Built Environment, No. 8 (2017): Nanostructured lime-based materials for the conservation of calcareous substrates

3rd Historic Mortars Conference, 11-14 September 2013, Glasgow, Scotland The consolidation process of old renders with loss of cohesion is nowadays performed usually with inorganic compatible products, such as calcium or barium hydroxide or ethyl silicate. The use of organic consolidants as acrylic or vinilic resins is discouraged due to its physico-chemical incompatibility with the original lime-based renders; these organic products work as adhesive in the original substrate, while inorganic consolidants contribute to recover the cohesion loss improving the binder amount and guarantying better durability and full compatibility.The restoration intervention on historic mortars, including consolidation, often causes aesthetic heterogeneity and prejudices, sometimes dramatically, the global legibility of the architectonic surface. The aesthetic function can be restored by chromatic reintegration, through several techniques, with resource to overpaints, for instance based on calcium hydroxide, pigments and silicates.In this study several consolidant lime-based products were produced and characterized. Pigments were added to the products, in order to achieve chromatic reintegration properties as well as consolidation. The consolidant products consist in aqueous dispersion of calcium hydroxide, a pozzolanic additive (metakaolin or diatomite) and mineral pigments, namely a yellow earth pigment and a synthetic red pigment. The incorporation of a pozzolanic material was made to improve the mechanical strength and durability of the binder.The consolidant products were applied on mortar specimen with a simulated cohesion loss, through a reduced binder quantity and an optimization of the aggregate grain size. Specimens were subjected to different storage conditions (50 and 95% RH), to verify the influence of curing conditions. Physico-mechanical and microstructural characterization was performed on the treated mortar specimens to verify the consolidant treatment efficacy. Consolidant treatments show intesting results, and their efficacy vary depending on the pozolanic addition; pigments do not influence that much the consolidation efficiency.