Artigos de Revista
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Water Vapor Emission From Rigid Mesoporous Materials during the Constant Drying Rate Period
It has long been thought that the evaporation rate from mesoporous materials during the constant drying rate period (CDRP) is equal to that of a free-water surface, due to the presence of a liquid film covering the surface of the material. In this article we review several early articles and demonstrate that the experimental scrutiny this hypothesis has received is insufficient. Further, we report a set of evaporative drying experiments on eight building materials whose results also do not confirm such hypothesis. Indeed, the drying rate during the CDRP is not equal either among the tested materials or between these and the free-water surfaces. To explain the differences in drying rate, we have looked at the influence of surface texture and porosity. We have concluded that surface texture, which could increase the effective surface area of the materials, did not have a relevant effect on the CDRP drying rate. However, we have found a good correlation between the CDRP drying rate and capillary porosity. This is consistent with the hypothesis that drying occurs at the pore level during the CDRP. Further, it contradicts the suggestion that there is a film of water covering the surface of the materials during this period.
Ano: 2012
Número Páginas:
12.
Autor(es): Gonçalves, T. D.; Brito, V.; Pel, L.
Revista: Drying Technology
Editor: Taylor & Francis
Volume:
30.
Keywords: Porous media; Pore network; Heat and mass transfer; Drying rate; Constant drying rate period
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Chemical Shrinkage of Pastes Made with Shrinkage Reducing Admixtures
Abstract. Shrinkage Reducing Admixtures (SRA) are being used more often in concrete structures in order to better control shrinkage cracks. High-performance concrete, nowadays with large application, has more proneness to crack at very early age due to the lower W/C. In this type of concrete, autogenous shrinkage is usually more important than drying shrinkage. Autogenous shrinkage is due to the volume decrease inherent to binder hydration reactions. The rate of these reactions is influenced not only by the type of binder but also by the presence of chemical admixtures. It is recognized that SRA delay the hydration, being a secondary effect of this type of admixtures. In this work changes on the degree of hydration of cement pastes with SRA and different binders are presented, using the chemical shrinkage test.
Ano: 2011
Número Páginas:
pp 105-113.
Autor(es): Ribeiro, A. C.
Revista: Key Engineering Materials
Editor: Trans Tech Publications
Volume:
Vol. 466 (2011).
Keywords: Admixtures; Shrinkage
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Coatings applied on damp building substrates: performance and influence on moisture transport
Dampness is a common condition in old buildings and, accordingly, many paint systems specific for this type of building allow for application on walls with nonnegligible moisture content. In spite of that, performance evaluation of these paints is normally carried out using dry substrates or even on free paint films. This article presents research performed on 16 commercial paint systems: seven silicate, three silicone, three hydro-pliolite and two lime-based systems, as well as one common vinyl emulsion paint that served as reference. Each paint was applied and cured both on dry and on damp mortar substrates. The test specimens were subjected to water vapor permeability tests and evaporative drying tests. The following conclusions could be drawn: (i) the way paint systems influence the drying of the substrate, to which they were applied and where they cured, may vary significantly depending on the moisture content of that substrate; (ii) vapor permeability, measured with specimens applied and cured on dry substrate, may be an acceptable way of predicting a paints influence on drying, provided that the paints are applied and cured on dry substrate or that their characteristics are not significantly affected by the moisture content of that substrate.
Ano: 2011
Número Páginas:
513525.
Autor(es): Brito, V.; Gonçalves, T. D.; Faria Rodrigues, P.
Revista: Journal of Coatings Technology and Research
Editor: Springer
Volume:
8 (4).
Keywords: Moisture transport; Drying; Damp; Old building; Paint system
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Construction and demolition waste generation and management in Lisbon (Portugal)
The management of construction and demolition waste (CDW) is essential in the formation, growth and renovation of urban areas. This paper presents part of a study on CDW generation and management in the Lisbon Metropolitan Area (LMA). CDW generation was estimated for 2006 and 2007 based on construction activity and waste load movements. The results revealed that in the municipality of Lisbon, remodeling construction activity prevailed, with CDW generation indicators of 954 t/day and a per capita rate of 0.60 t/year. Both values are above the average for the LMA and its two sub-regions (Greater Lisbon and the Setúbal Peninsula). The installed infrastructure for CDW management identified in the LMA is situated within a maximum distance of about 23 km from the geometric center of the city of Lisbon. Despite the fact these locations favor the municipality of Lisbon, the occurrence of illegal dumps is still a reality. A notable effort towards environmental education addressing CDW management is under way so as to make involved citizens aware of the recent CDW legislation, Decree-Law Nr. 46/2008, as well as of the problems arising from scenarios of environmental degradation and uncontrolled use of natural resources in the civil construction sector. Policies are outlined aiming to move towards the more judicious management of CDW.
Ano: 2011
Número Páginas:
13.
Autor(es): Braz de Melo, A.; Gonçalves, A.; Martins, I. M.
Revista: Resources, Conservation and Recycling
Editor: Elsevier
Volume:
55 (12).
Keywords: Management; Generation; Demolition; Construction; Waste
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Evaluation of Adhesion Promotion Techniques for Structural Bonded Timber Joints
Long-term durability of a structural adhesive joint is an important requirement, because it has to be able to support the required design loads, under service conditions, for the planned lifetime of the structure. Epoxy adhesives, whilst not ideal, are currently the best family of adhesives for in situ repair operations. As long as the bonded joint remains dry and unexposed to high service temperatures, epoxy adhesives produce strong bonds to timber. However, once they are exposed to severe stresses as a result of repeated water soaking and drying cycles, the bonded joint delaminates and does not fulfil the requirements for structural timber adhesives intended for exterior exposure. One way of improving bond durability is through the use of surface treatments prior to bonding. In this study, the effects of corona discharge surface treatment, hydroxymethylated resorcinol (HMR) and ?-glycidoxypropyltrimethoxysilane (GPMS) adhesion promoters on the durability enhancement of pine, iroko, and oak bonded joints were evaluated. The results proved that surface modification methods for adhesion promotion can be adapted to cellulosic substrates with significant improvements in bonded joint durability.
Ano: 2011
Número Páginas:
331352.
Autor(es): Custódio, J.; Broughton, J.; Cruz, H.
Revista: The Journal of Adhesion
Editor: Taylor & Francis Group, LLC
Volume:
87(4).
Keywords: Surface treatments; Structural bonded joints; Solid timber; Durability; Adhesion promoters; Epoxy
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Rehabilitation of timber structures Preparation and environmental service condition effects on the bulk performance of epoxy adhesives
Epoxy adhesives have been used for many years in the rehabilitation of timber structures and are currently the most appropriate adhesive type for on-site operations. However, because they exhibit excellent initial joint strength when tested in standard climate conditions, there has not been a major concern about their service durability. In order to contribute to the ongoing discussion on the reliability of these adhesives, a study was conducted to evaluate the effect of environmental service conditions on the durability of four commercial two-component structural epoxy adhesives, as well as the effect that the type of mixing, curing and postcuring conditions, as well as the presence of moisture have on the adhesives viscoelastic properties. It was found that the preparation conditions, cure schedule and moisture have a significant effect on the performance of the bulk adhesives. Moreover, it was found that under ambient conditions there is potential for under-cure or slow progression of cure for the epoxy adhesive products typically employed in these applications, which in turn can compromise the durability of a bonded joint.
Ano: 2011
Número Páginas:
3570-3582.
Autor(es): Custódio, J.
Revista: Construction and Building Materials
Editor: Elsevier, Ltd.
Volume:
25(8).
Keywords: Service conditions; Moisture; Preparation conditions; Epoxy adhesives; Durability
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A review of factors influencing the durability of structural bonded timber joints
Adhesive bonding technology has played an essential role in the development and growth of the rehabilitation and repair of timber structures. The ability of a structural joint to maintain satisfactory long-term performance, often in severe environments, is an important requirement of a structural adhesive joint, as the joint should be able to support design loads, under service conditions, for the planned life time of the structure. A number of factors determining the durability of structural adhesive joints have been identified and can be grouped in three categories: environment, materials and stresses. The environment is dominated by temperature and moisture. The materials category includes the adherend, the adhesive, and the inter-phase between them both. The last category refers to the stresses to which the bond is subjected during or after exposure to service environment, affecting both longevity and residual strength. Since this subject in relation to timber bonding is very disperse within the literature, this paper will focus briefly on each of the aforementioned factors, thus providing a general understanding on the factors that influence the durability of bonded timber joints.
Ano: 2009
Número Páginas:
173-185pp.
Autor(es): Custódio, J.
Editor: International Journal of Adhesion and Adhesives
Volume:
29/2.
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Activation of timber surfaces by flame and corona treatments to improve adhesion
Long-term durability of a structural adhesive joint is an important requirement, because it has to be able to support the required design loads, under service conditions, for the planed lifetime of the structure. One way of improving bond durability is through the use of surface treatments prior to bonding, which will activate the adherends' surface, making it more receptive to the adhesive. In this study, the effects of two surface pre-treatments (corona discharge and flame ionization) on three timbers (maritime pine, iroko, and European oak) were evaluated quantitatively through contact angle measurements. These measurements allowed the determination of the changes in the timber surface thermodynamic characteristics, thus indicating which pre-treatment performed better. The results showed that both techniques increased each timber's surface free energy, which could translate into a durability enhancement of bonded joints. Overall, the corona-discharge treatment looks more promising, since this treatment leads to a bigger increase in the timber's surface energy, especially in its polar component, whilst also tended to be less species specific, less susceptible to variation, and the treatment effects lasted longer for this type of treatment.
Ano: 2009
Número Páginas:
167-172pp.
Autor(es): Custódio, J.; Broughton, J.; Cruz, H.; Winfield, P.
Editor: International Journal of Adhesion and Adhesives
Volume:
29/2.
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Assessment of characteristic compressive strength in structures by the rebound hammer test according to EN 13791: 2007
The European Standard EN 13791 provides methodologies for estimating concrete compressive strength in structures. This standard covers the testing of cores as well as the use of indirect methods, such as the rebound hammer, USPV and pull-out tests. This communication refers to a study carried out in a building where the methodologies presented in EN 13791 has been applied to estimate the in-situ characteristic strength, based on a widened set of pairs of rebound hammer and core compressive strength test results. A statistical interpretation of the two alternatives provided by the standard for the establishment of the relationship between the in-situ strength and the rebound number is presented, and some relevant aspects related to the regression analysis not mentioned by the standard, such as the precision of the rebound number and the confidence level, are discussed.
Ano: 2009
Número Páginas:
249-254.
Autor(es): Monteiro, A.; Gonçalves, A.
Editor: Laboratoire Central des Ponts et Chaussées
Keywords: Análise de regressão; Resistência do betão in situ; Esclerómetro; Intervalos de tolerância
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A review of adhesion promotion techniques for solid timber substrates
The use of primers, coupling agents, and other surface treatments to enhance adhesion is now common in the aerospace, automotive, and plastics industries, where they are used to develop highly durable bonds to metals, advanced composites, ceramics, and plastics. However, such treatments are virtually non-existent in the wood products industry although they could solve important adhesion problems. In particular, adhesion promoters can enhance the environmental durability of epoxy bonded joints, and they can enhance the reliability of bonds to timber treated with wood preservatives. A review of current findings is provided that attempts to gather the scarce and disperse information available in the literature about adhesion promotion techniques for bonded solid timber joints. A general overview of the research needs on this topic is also given.
Ano: 2008
Número Páginas:
502529pp.
Autor(es): Custódio, J.; Broughton, J.; Cruz, H.; Hutchinson, A.
Revista: The Journal of Adhesion
Editor: Taylor & Francis Group, LLC
Volume:
84 (6).
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Comunicações
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Caracterização ambiental de RCD A experiência do LNEC
A avaliação da libertação de substâncias perigosas em resíduos de construção e demolição permite compreender o possível risco para o ambiente associados à sua utilização. São aqui apresentados alguns exemplos dessa avaliação bem como a abordagem europeia neste âmbito.
Ano: 2017
Número Páginas:
4p.
Autor(es): Martins, I. M.; Roque, A. J.; Freire, A. C.
Editor: LNEC
Keywords: Substâncias perigosas; Lixiviação; Caracterização ambiental; RCD
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Characterization of filler fraction from the production of recycled sand from construction and demolition waste
The concept of circular economy envisages that the highest utility and value of a material can be achieved through proper management along its all life cycle. Therefore reducing waste, through increased reuse and recycling, is a major driver to close the loop. Within this framework, construction and demolition waste, which constitutes up to 30% of world waste generation, is a priority in order to achieve a high level of resource efficiency in the construction sector. In general, it is noticed that the fine fraction from traditional CDW processing, representing from 40 to 60% mass of the CDW mineral phases, is not suitable to be used as a secondary material for manufacture of concrete where high mechanical performance is required. Moreover, the filler fraction produced on recycling processes is rarely considered for recycling due to its high surface area and irregular shape. Filler properties depend on previous construction material composition and mineral processing applied for recycling. This paper aims to characterize the filler fraction from the production of recycled sand from construction and demolition waste processing, by particle size distribution, chemical and mineralogical composition and specific density and highlights some drawbacks related to their application as filler in cementitious building materials.
Ano: 2017
Número Páginas:
68-71 pp.
Autor(es): Martins, I. M.; Ulsen, C.; Kahn, H.; Landmann, M.; Müller, A.
Revista: Conference Proceedings of HISER International Conference - Advances in Recycling and Management of Construction
Editor: TU Delft Library Publications
Keywords: Recycled filler; Products characterization; Mineral processing; CDW recycling
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Evaluation of damage in concrete from structures affected by internal swelling reactions. A case study
Currently, a significant number of concrete infrastructures (e.g. dams and bridges), in Portugal and throughout the world, are affected by internal swelling reactions (ISR). Among the various reactions that can cause concrete swelling, the most common in Portugal are the alkali-silica reaction (ASR) and the internal sulfate reaction (DEF). From the 60 large concrete dams that are currently being monitored in Portugal, there are 19 dams in which the concrete swelling phenomena has already been identified. It is expected that the number of ISR affected bridges will soon surpass that of dams. In Portugal, a dam was demolished and replaced by a new one in 2014 due to ASR induced expansion and distress, a bridge was decommissioned and replaced by a new one in 2015 due to deleterious development of both ASR and DEF, and several bridges had to suffer expensive rehabilitation works the keep them operational. Moreover, there are still new structures being built that will ultimately suffer from ISR deterioration either because existing guidance was not followed or simply due to limitations of available recommendations. As such, ISR-affected structures will continue to wave our infrastructure for years to come. Existing knowledge on ISR does not allow for a complete assessment of the actual condition of an affected structure and an accurate prediction of the mechanical properties deterioration and, consequently, of the period during which the structure will effectively perform its function, essential for the timely and cost-effective planning of the necessary mitigation, rehabilitation or reconstruction works. Therefore, to help surpassing this situation, a research project is being conducted at LNEC to contribute to the establishment of a method for the accurate determination of the current level of ISR progression and of the deterioration of the concrete mechanical properties. These are essential to the adequate overall appraisal of an affected structure, and the development of structural models that predict risks to structural integrity, potential for further deterioration due to other mechanisms, need for mitigation or remediation actions, and the remaining service life of the affected structure. This communication aims to contribute to the ongoing discussion of this topic by the scientific community and, therefore, presents the methodology followed to assess the condition of the concrete from an ISR-affected bridge in Portugal. It includes an extensive experimental campaign, performed to concrete cores extracted from the structure, comprising the latest advances in the field, to allow for an adequate diagnosis and prognosis of the expansive reactions development in the concrete. The results obtained in the study evidenced the utility of such a methodology on the appraisal of the actual expansion level attained to date in the concrete from ISR-affected structures.
Ano: 2017
Autor(es): Custódio, J.; Ribeiro, A. C.
Editor: International Conference on Structural Integrity
Keywords: Evaluation; Damage; Concrete infrastructures; DEF; ASR; Internal swelling reactions
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Performance of C&DW materials for road applications validated by field monitoring
SUPREMA Sustainable Application of Construction and Demolition Recycled Materials in Road Infrastructures was a research project developed by the Laboratório Nacional de Engenharia Civil (LNEC), in cooperation with the University of Lisbon (IST). The use of recycled materials has major environmental and economic benefits. Its recycling contributes for a more sustainable construction and rehabilitation of road pavements. The main goals of this project were to achieve a deeper knowledge on recycled materials and correspondent technologies and to increase the confidence of road agencies and construction companies for its application in road pavements. The objective of the paper is to analyse the mechanical performance of recycled aggregates, from construction and demolition waste (C&DW), used in unbound granular layers and evaluated on experimental sections of asphalt pavements. Four sections were instrumented with strain gauges and load cells. The recycled aggregates used in these sections were: crushed concrete, crushed mixed concrete and crushed and milled reclaimed asphalt pavement (RAP). A crushed natural limestone aggregate was used in one section as a reference material. The sections were submitted to in situ load tests performed by the Falling Weight Deflectometer (FWD). In addition, an extensive program of laboratory tests was also performed related to geometrical, physical, mechanical, chemical and environmental characteristics. This paper presents the mechanical behaviour of aggregate layers obtained from the back-analysis of FWD tests results and from the instrumentation measurements. In general, it was concluded that stiffness of unbound granular layers with recycled aggregates could be considered equivalent to the stiffness of layers constructed by natural aggregates. Results of resilient modulus obtained for the studied recycled aggregates could be useful for pavement design purposes.
Ano: 2017
Número Páginas:
202-205pp..
Autor(es): Neves, J.; Freire, A. C.; Roque, A. J.; Martins, I. M.; Antunes, M. L.
Revista: Conference Proceedings of HISER International Conference - Advances in Recycling and Management of Construction
Editor: TU Delft Library Publications
Keywords: Performance; Recycling; Pavement; Road; C&DW
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Production of low porosity recycled sand from construction and demolition waste
The existing construction waste recycling technologies and standards have been long applied in construction and demolition (C&D) waste recycling, mainly focused on the production and use of coarse recycled aggregates. Very few papers and process focus on the production of recycled sand although some previous results show that fine aggregates fraction (below 4.8 mm) represents around 40 to 60% (in mass) of the Brazilian waste and it is usually down cycled as road sub-base or disposed in landfills. The quality of the recycled aggregate is strictly related to the content of porous and low strength phases, as the patches of cement attached to the recycled aggregate. Despite being the crucial factor for aggregate performance, the removal of adhered cement paste is not a simple task. Some technologies have already been described in the literature, even though, to the moment none of these technologies has clearly succeeded in reaching the large market available. This paper presents a summary of the main properties of the sand produced from C&D waste by tertiary crushing at vertical shaft impactor crusher (attrition and abrasion comminution). Additionally mineral processing technologies were applied on the attained product, such as density concentration by shaking table and spirals and magnetic separation at rare earth roll separator. The main properties of recycled sand are discussed and compared to the previous C&D waste, respectively: apparent density, water absorption, chemical composition, porosity, particle shape and cement paste content. The results demonstrated that the comminution by vertical shaft impact crusher allowed producing a VSI-sand with low porosity and water absorption. The concentration by shaking table at narrow sieve fractions led to a product with low porosity and reduced content of cement paste, although products from spiral concentrator for the bulk sample had only the effect of classification instead of concentration. The non-magnetic products presented similar characteristics of the heavy product from the shaking table plus separation of micaceous minerals. The aim of producing sand from construction and demolition waste through mineral processing unit operations changes the recycling approach and contributes for upcycling the recycled sand.
Ano: 2017
Número Páginas:
77p.
Autor(es): Ulsen, C.; Kahn, H.; Antoniassi, J.; Martins, I. M.
Revista: Conference Proceedings of HISER International Conference - Advances in Recycling and Management of Construction
Editor: TU Delft Library Publications
Keywords: Mineral separability; Products characterization; Mineral processing; Recycled sand; CDW recycling
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Production technology and techno-historical value in faience azulejos
Aloïs Riegl in The Modern Cult of Monuments, originally published in 1903, was one of the first to ascribe a historical value to the results of a technology when he stated that even a torn-off slip of paper with a short unimportant note contains historical value for the development of paper manufacturing, script and writing materials. Glazed ceramic tiles (azulejos in Portuguese) are widely appreciated and studied for their artistic content. Their historical value is dully recognized but research deals mostly with the painting, the use of colour, the subjects or designs depicted in historiated or pattern panels and the purpose of their use over time. There is however an important historical value in their technology. The present text makes an overview of the pre-industrial technology of tile-making and offers some examples of how the historical content in that technology can be extracted and interpreted.
Ano: 2017
Número Páginas:
43-54pp.
Autor(es): Mimoso, J.; Esteves, L.
Revista: IMaTTe 2017 Book of Proceedings
Editor: Laboratório Nacional de Engenharia Civil
Keywords: Historical value in technology; Azulejo-making technology
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The archive oh historical materials in digital era as cultural value
Documenting and preserving materials data is important both to fulfill researchers needs and to obtain social benefits concerning the related educational and historical value. The samples repository is also demanded as a basis for further understanding, innovation and development, besides the preservation of the materials historical value and information. The dissemination of those materials importance to non-specialized interested publics may also be enhanced by a database. DB-HERITAGE project (Database of building materials with historical and heritage interest) discusses in this paper the meaning of the archive as a cultural value that is established from the relationship between tangible (physical archive) and intangible (digital archive). Reflecting on the archive of historical materials as a heritage value, it is pointed out its significance for the valorization of the architectural heritage
Ano: 2017
Número Páginas:
407-412pp.
Autor(es): Santos Silva, A.; Menezes, M.; Correia, M. J.
Editor: LNEC
Keywords: Web-based free database; Free ICT tools; Architectural heritage; Traditional techniques; Construction materials
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The importance of technological knowledge for the valorization of azulejo heritage
In this article considerations regarding the importance of recovering and protecting the knowledge of tile production techniques are elaborated. An overview of the Portuguese tile production system is made. The intangible method of knowledge transfer through oral dissemination and learning by observing and executing/imitating is observed. A comparison is made with the dutch case, where a larger amount of tangible historic information exists namely technical treatises and potters books - describing the materials, recipes and techniques used for historical tile production. The preservation of this knowledge has allowed potteries (such as Makkum and Harlingen) to continue to use similar raw materials and techniques. This has highlighted the need to create sources of information to contribute to historical information regarding Portuguese tile production techniques. The physicochemical characterization of tiles enables us to draw information about raw materials and production methods. The possibility of gathering of information from contemporary tile artisans-artist has also been suggested, namely from factories that are still functioning or that have functioned in the past. Above all, the article will explore the technical knowledge of tile production as an important intangible cultural value in the construction/development of Azulejo as Heritage.
Ano: 2017
Número Páginas:
55-66pp.
Autor(es): Morais Pereira, S.; Menezes, M.; Lookeren-Campagne, K.
Revista: Proceedings IMaTTe2017- Intangibility Matters - International conference on the values of tangible heritage
Editor: LNEC
Volume:
RNI 100.
Keywords: Methods of creation; Azulejo; Technical knowledge; Cultural value
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The importance of technological knowledge for the valorization of azulejo heritage
In this article considerations regarding the importance of recovering and protecting the knowledge of azulejo production techniques are elaborated. A tentative overview of the Portuguese azulejo production system is made. The method of knowledge transfer through oral dissemination and learning by observing and executing/imitating is noted. A comparison is made with the Dutch case, where a larger amount of tangible historic information exists namely technical treatises and potters books - describing the materials, recipes and techniques used for historical tile production. The preservation of this knowledge has allowed potteries (such as Makkum and Harlingen) to continue to use similar raw materials and techniques. This has highlighted the need to create sources of information to contribute to the research and preservation of knowledge regarding Portuguese azulejo production techniques. The physical-chemical characterization of azulejos enables us to draw information about raw materials and production methods. The possibility of gathering information from contemporary azulejo artisans has also been suggested, namely those related to workshops and factories. Above all, the article will explore the technical knowledge of azulejo production as an important intangible cultural value in the construction/development of azulejo as Heritage.
Ano: 2017
Número Páginas:
55-66pp.
Autor(es): Morais Pereira, S.; Menezes, M.; Lookeren-Campagne, K.
Revista: IMaTTe 2017 Book of Proceedings
Editor: Laboratório Nacional de Engenharia Civil
Keywords: Tiles; Manufacture of azulejos; Cultural value; Technical knowledge
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The integration of azulejos in the modern architecture of Portugal as a unique case in Europe
With the increasing international appreciation of Portuguese azulejos, spurred not only by the acknowledgement of their integration in Baroque architecture as a unique heritage, but also by the continued use of painted tiles that spans to this day, azulejos have been a subject of interest and research. The technology of manufacture, the forms of decay and the materials and techniques for restoration have been studied for pre-20th century azulejos. However, such studies did not encompass modern azulejos, manufactured after the second world war, which must be understood and conserved now, so that they will be available for future appreciation. Understanding the relevance of modernist azulejos in Portugal as cultural heritage and the raison dêtre of their integration, not only in Portuguese, but also in Brazilian architecture is important to discuss their preservation. The aim of this paper is to discuss and attempt to assign values to modern azulejos in Portugal as an unique regional trend in the modern movement in Europe.
Ano: 2017
Número Páginas:
139-147pp.
Autor(es): Geraldes, C.; Pais, A.; Mimoso, J.
Revista: IMaTTe 2017 Book of Proceedings
Editor: Laboratório Nacional de Engenharia Civil
Keywords: Values; Portugal; Modern architecture; Azulejos
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Livros
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C3Places - Using ICT for Co-Creation of Inclusive Public Places
This e-book and correspondent platform MyC3Place present the collection of the outcomes carried out by the partners of the C3Places Project. It explores the new dynamics of open spaces as a trusted service for community and expands our understanding on how mediated public open spaces function, paying attention to stakeholders, local context and different social groups. The e-book shows how it's possible to increase the quality of public open spaces (squares, parks, green spaces) as a communitys service, reflecting through ICT the needs of different social groups. Public spaces are critical for cultural identity, as they offer the place for interactions among generations and ethnicities. Even in the digital era, people still need contact with nature and other people to develop different life skills, values and attitudes, to be healthy, satisfied and environmentally responsible. Using ICT and co-creating with users, this e-book expands our knowledge on meeting emerging citizens needs about the future public space. All the contents are classified by means of keywords that are described on the following pages. Then the work of each partner is presented in detail.
Ano: 2021
Número Páginas:
83.
Autor(es): Costa, C.; Batista, J.; Almeida, I.; Menezes, M.
Revista: Using ICT for Co-Creation of inclusive Public Spaces
Editor: Edições Universitárias Lusófonas
Keywords: co-creation; public spaces; ICT; C3Places
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Co-Creation of Public Open Places. Practice - Reflection - Learning
C3Places - using ICT for Co-Creation of inclusive public Places is a project funded under the scheme of the ERA-NET Cofund Smart Urban Futures / Call joint research programme (ENSUF), JPI Urban Europe, https://jpi-urbaneurope.eu/project/c3places. C3Places aims at increasing the quality of public open spaces (e.g. squares, parks, green spaces) as community service, reflecting the needs of different social groups through ICTs. The notion of C3Places is based on the understanding that public open spaces have many different forms and features, and collectively add crucial value to the experience and liveability of urban areas. Understanding public open spaces can be done from a variety of perspectives. For simplicitys sake, and because it best captures what people care most about, C3Places considers the public dimension to be a crucial feature of an urban space. Public spaces are critical for cultural identity, as they offer places for interactions among generations and ethnicities. Even in the digital era, people still need contact with nature and other people to develop different life skills, values and attitudes, to be healthy, satisfied and environmentally responsible. The book aims to spark discussion on the co-creation of public open spaces through the active involvement of different stakeholders in the production of a more inclusive, attractive and responsive urban environment. It intends to help researchers, governments and drivers in understanding and implementing more collaborative actions. The authors share experiences, visions and reflections on how co-creation and participatory processes can open up possibilities for a sustainable and equitable future. This book emphasises three dimensions: practice, reflection, and learning. Practice concerns driving actions, identified and analysed experiences that serve as key models. Reflection refers to exploring and examining the results and performances of a co-creation process. Co-creation is not the search for a final product, but rather a process and a new path to more responsive and inclusive communities. Learning refers to the knowledge transfer and replication induced by the synergy of the different actors involved in this book. The chapters which constitute this work were completed prior to Spring 2020, so the research and insights do not reference the global public health crisis caused by Covid-19. However, in such challenging times the argument for co-creation approaches to increase the potential of public spaces to support a range of inclusiveness outcomes is even stronger. This publication is based upon work of C3Places Project. The C3Places Project has received funding from the European Unions Horizon 2020 research and innovation programme under grant agreement No 693443 and from FCT (Portuguese Funding Agency for Science, Research and Technology).
Ano: 2020
Número Páginas:
264p..
Autor(es): Costa, C.; Ma?iulien?, M.; Menezes, M.; Marui?, B.
Revista: Co-Creation of Public Open Places. Practice - Reflection - Learning
Editor: Edições Universitárias Lusófonas
Volume:
4.
Keywords: Cocreation; C3Places; Urban public space
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Neighbourhood & City - Between digital and analogue perspectives
This volume aims to promote discussion and critical thinking on the urban environment at the intersection of the neighbourhood and the city, along their socio-spatial relations, from an interdisciplinary, multidimensional and international perspective. The chapters cover various aspects related to the meaning of living, intervening, planning, managing, thinking about and producing the city in the digital era, with a view to increasing the understanding of neighbourhoods as part of a wider consideration of social and sustainable development and the need for greater care of urban communities. This has a direct impact on public open spaces, which lie at the core of CyberParks. The international scope of the edition is enhanced by its bilingual nature, as this volume targets, in addition to a European readership, also the readership of Portuguese-speaking countries. This publication is based upon work from COST Action TU1306, supported by COST (European Cooperation in Science and Technology).
Ano: 2019
Número Páginas:
451p..
Autor(es): Menezes, M.; Costa, C.
Revista: Neighbourhood & City - Between digital and analogue perspectives
Editor: Edições Universitárias Lusófona
Volume:
3.
Keywords: City; Cyberparks; Analogue; Digital
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On the origin of majolica azulejos production in Portugal
Vários
Ano: 2019
Número Páginas:
138p.
Autor(es): Pais, A.; Reis, M.; Campelo, J.; Mimoso, J.; Silva, M.; Morais Pereira, S.; Antunes, M.; Cardoso, A.; Esteves, L.; Candeias, A.; Filipe, V.; Matos, M.; Morna, T.; Simões, J.
Revista: Estudos em Cerâmica Vidrada Patrimonial
Editor: LNEC
Keywords: PT; Physical-chemical characterization; Azulejo; Manufacture; Glazed ceramics; Historic heritage
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Livro de Resumos - Congresso Ibero-Americano "Património, suas matérias e imatérias
Publicação que regista os resumos expandidos realizados no âmbito do Congresso Ibero-americano "Património, suas matérias e imatérias", realizado nos dias 2-3 de novembro de 2016 no LNEC, contendo ainda em CDrom, os artigos completos.
Ano: 2016
Número Páginas:
366p.
Autor(es): Menezes, M.; Delgado Rodrigues, J.; Costa, D.
Editor: LNEC
Keywords: Valor; Património imaterial; Património material; Reabilitação; Conservação do património; Participação social; Desenvolvimento sociocultural; Património cultural; Congresso Internacional
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Simpósio Património em Construção - Contextos para a sua preservação
Em 2011 cumpriram-se 100 anos sobre a publicação da Lei de Reorganização dos Serviços Artísticos e Arqueológicos da 1ª República (Maio de 1911). Este diploma constituiu uma referência incontornável no enquadramento do conceito de património que iria influenciar toda a prática da sua salvaguarda em Portugal. Por coincidência, cumpriram-se também neste ano os 80 anos da Carta de Atenas (Outubro de 1931), um marco histórico na produção de documentos orientadores de cariz internacional, que veio incentivar a produção de novas cartas e outros documentos internacionais que, em larga medida, ainda definem e sustentam as actuais práticas de preservação do património. O Instituto de História da Arte da Universidade de Lisboa e o Laboratório Nacional de Engenharia Civil quiseram com este simpósio assinalar aquelas efemérides oferecendo às comunidades científicas e profissionais uma oportunidade de reflectirem sobre estes acontecimentos pioneiros e debaterem as consequências que eles tiveram no período transcorrido desde então, como forma de compreender melhor a salvaguarda do património nos dias de hoje, perante os desafios e exigências da sociedade moderna. Os artigos recebidos, e que constam nas presentes actas, demonstram o interesse que o tema suscita e confirmam que o País está bem apetrechado para cuidar do seu património em todas as vertentes que tal objectivo exige. Ao juntarmos as valências de duas instituições tão diferenciadas, procurámos mostrar que a preservação é um conceito multifacetado, que necessita de contributos diversos, mas precisos, e que não pode ser abordado de forma unilateral ou voluntarista por um qualquer grupo profissional ou ditado por meios burocráticos como medida normalizada ou normalizável. Os trabalhos agora publicados dão conta dos primórdios das preocupações sobre preservação, discutem problemáticas que percorreram o Séc. XX e reflectem sobre as situações actuais, cumprindo cabalmente as nossas expectativas e enriquecendo o acervo de exemplos e de doutrinas que nos permitem afirmar que não é por falta de conhecimento, de experiências ou de competências realizadoras que ainda hoje vemos acontecerem intervenções desqualificadas, mal preparadas e desajustadas. As presentes actas aí estão para demonstrar que fazer mal ou abandonar património não têm que ser fatalidades de um país.
Ano: 2011
Número Páginas:
425pp.
Autor(es): entidade LNEC
Editor: LNEC
Keywords: Congresso internacional; Conservação de património; Otecção do património; Património; Pt
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Avaliação, Conservação e Reforço de Estruturas de Madeira
N/A
Ano: 2009
Autor(es): Saporiti Machado, J.; Cruz, H.; Custódio, J.; Palma, P.; Dias, A.
Editor: Verlag Dashöfer
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Capítulos de Livros
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ICE manual of construction materials
N/A
Ano: 2009
Autor(es): Broughton, J; Custódio, J.
Editor: Thomas Telford Ltd
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Teses de Doutoramento
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Conservação de construções de taipa: argamassas de reparação.
Atualmente existe grande interesse pelas técnicas construtivas com terra crua, que tinham caído em desuso mas que ressurgiram com a conscencialização face à ecoeficiencia e no sentido de explorar recursos locais reutilizáveis. A taipa é, a nível mundial, uma das mais antigas e difundidas técnicas de construção. Em Portugal a taipa reune grande atenção porque é uma das principais técnicas utilizadas na nova construção com terra. Mas esta atenção decorre também da necessidade de reabilitação de edifícios antigos e da existência de um vasto e valioso património arquitetónico, que precisa ser preservado. Muitos dos edifícios antigos de terra deterioraram-se por falta (ou ineficiência) de manutenção e reparação. De fato, existe um elevado desconhecimento ao nível das técnicas de reabilitação e conservação. O presente trabalho de investigação explora a questão da adequabilidade de argamassas para a reparação de paredes de taipa. A escassa informação nesta área justificou o estudo das caraterísticas mais adequadas para estas argamassas de reparação e definição de recomendações para sua aplicação. Partiu-se do pressuposto que, para perspetivar intervenções de reparação com maior ciclo de vida, é importante asseverar não só a durabilidade das argamassas de reparação, mas também a sua compatibilidade com a parede. A principal conclusão é que, sempre que possível, as argamassas devem ser efetuadas com a mesma terra utilizada na parede ou com materiais tão semelhantes a esses quanto possível, para que as propriedades físicas, mecânicas e químicas sejam compatíveis com as da parede a reparar. Se a taipa não tiver sido estabilizada com ligantes minerais, estes não devem também ser utilizados nas argamassas de reparação. Observou-se ainda que as argamassas estabilizadas com ligantes minerais apresentam uma absorção capilar muito mais rápida do que o mesmo tipo de argamassas sem estabilização e que a utilização de fibras vegetais potencia o aparecimento de bolores, quando as argamassas se encontram em ambientes com elevadas humidade relativa.
Ano: 2013
Número Páginas:
357p.
Autor(es): Gomes, I.
Keywords: Argamassas de reparação; Taipa; Construção com terra; Terra
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Salt crystallization in plastered or rendered walls
This thesis was aimed at understanding the behaviour of plasters and renders on salt-loaded walls. The current state-of-the-art and state-of-the-practice were accessed focusing particularly on old plastered/rendered buildings and their conservation practice in Portugal. Afterwards, experimental work was carried out aiming at answering the identified questions. Two laboratory techniques, for relative humidity control with salt solutions and for salt content determination by hygroscopic moisture content measurements, were investigated. Drying of salt-loaded materials was studied by means of drying experiments monitored using a magnetic resonance imaging (MRI) technique. The behaviour of plasters and renders in relation to salt crystallization was then accessed by means of crystallization tests and MRI-monitored drying tests. Most drying and crystallization tests were carried out on specimens composed by a plaster or render applied on a given substrate. Finally, the study of five old buildings in Portugal provided an insight into practice-related salt decay features. On the basis of this research, guidelines are proposed to select plasters and renders for salt loaded walls. Conclusions were also achieved on: (i) possibilities and limitations of the test methods, particularly salt crystallization tests, and diagnostic methodology used; (ii) salt decay processes, namely, influence of soluble salts on drying, mechanisms of salt-induced dampness and salt distribution in masonry; (iii) reasons for sodium chloride being typically much less damaging than sodium sulfate in laboratory tests; (iv) influence of factors such as the type of salt, kind of substrate material or presence of a paint layer on the behaviour of plasters and renders; (v) factors that can account for a worsening of salt damage after restoration interventions; (vi) field or application conditions that favour salt damage.
Ano: 2007
Número Páginas:
262.
Autor(es): Gonçalves, T. D.
Keywords: Conservation; Built heritage; Cultural heritage; Renders; Plasters; Suflorescence; Efflorescence; Salt damp; Salt weathering; Salt decay; Crystallization; Salts; Efflorescencesoluble salts
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Dissertações de Mestrado
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Absorção por capilaridade de soluções salinas em materiais porosos
A ação dos sais solúveis e humidade nos edifícios antigos é uma causa frequente da sua degradação. Pretende-se com este trabalho estudar experimentalmente, através de ensaios laboratoriais, de que forma diferentes tipos de sais dissolvidos em água influenciam a absorção por capilaridade em materiais porosos. O levantamento do estado da arte incidiu sobre a ação de degradação dos sais solúveis sobre os materiais porosos, sobre as características dos materiais porosos e foca também os mecanismos de transporte da água, no estado liquido e de vapor, envolvidos nos processos de absorção capilar e secagem. A campanha experimental realizada incluiu o ensaio de absorção por capilaridade e o ensaio de secagem. Os materiais porosos utilizados foram o tijolo e a argamassa e utilizaram-se seis soluções salinas, de concentração saturada: cloreto de sódio, sulfato de sódio, cloreto de potássio, nitrato de sódio, nitrato de potássio e carbonato de sódio. Realizaram-se os mesmos ensaios com água, que serviram como referência. Esta dissertação permitiu tirar conclusões sobre: i) a influência dos sais na absorção por capilaridade; ii) processos de degradação, influência dos sais solúveis na secagem de materiais porosos; iii) a correlação existente entre a degradação dos materiais porosos com o tipo de sal.
Ano: 2013
Número Páginas:
90.
Autor(es): Azevedo, J.
Keywords: Materiais porosos; Sais solúveis; Secagem; Absorção capilar
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The blue in Portuguese historical azulejos
Although Portuguese azulejos are such an important heritage asset, having been extensively studied from the Art Historian viewpoint, the knowledge concerning the raw materials used and the details of the technological manufacturing process is very limited. The research project behind this dissertation was aimed at improving the present knowledge as concerns the composition of the blue pigment used in the 17th and 18th centuries. A representative set of azulejos spanning at least 200 years from ca. 1600 to 1800 was selected and the composition of the blue colour in their glazes analysed. The results were assessed aiming to answer the following main questions: i- What are the characteristic compositions of the colour (pigment and impurities) and how do they relate with the chronology of the azulejos? ii- What are the compositional traits that bear on the shades of the blue colour? iii- Can Portuguese azulejos be separated from Dutch and Spanish productions, at times when they co-existed in Portugal, solely by the composition of the blue colour? iv- Is the composition of the blue colour related with provenance of azulejos within Portugal? v- Are there grounds to suspect that at some time the Portuguese used, besides the well-known German zaffre, alternative sources of blue colour imported through their wide sea trade routes?
Ano: 2012
Número Páginas:
110.
Autor(es): Fares, M.
Keywords: Majolica colours; Cobalt blue; Glazed ceramics; Azulejo
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Drying of red ceramic brick. Effect of five silicone-based water-repellent treatments.
The presence of moisture inside a material whose surface was treated with a water repellent agent may give rise to unwanted side-effects. Indeed, the temporal and spatial significance of moistening events may be intensified if a water-repellent, as any other kind of treatment, hinders drying. This effect can be particularly relevant for historical buildings, where moisture from varied origins is recurrently present in the masonry, but is also pertinent for more recent constructions since water often finds ways to penetrate the building elements, through cracks or joints. This article discusses the application of water repellent treatments on ceramic brick, with regard to drying of the masonry. The influence of cracks parallel or perpendicular to the surface is taken into account. Five silicone-based treatments were studied. The treated or untreated material was subjected to capillary absorption tests by which the effectiveness of the water repellent effect was estimated, as well as water vapour permeability tests and drying tests. The effectiveness of four out of the five treatments is high. Vapour permeability is not much affected in one case, when the cracks are parallel to the surface, and in none of the cases, when they are perpendicular. Nonetheless, drying is significantly delayed by any of the five products, both in the case where the cracks are parallel to the surface as when they are perpendicular.
Ano: 2011
Número Páginas:
81-92.
Autor(es): Couto, S.; Gonçalves, T. D.; Grandão Lopes, J.
Keywords: Drying; Surface treatment; Hydrophobic; Water-repellent; Ceramic brick
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Análise macroscópica do efeito de dois modificadores de cristalização com baixa toxicidade
A presente dissertação visa avaliar a eficácia de dois modificadores de cristalização com baixa toxicidade quando em aplicados em dois materiais porosos, contaminados com dois tipos de sal. Foram testados o ácido cítrico e o ácido fosfocítrico, aplicados por absorção capilar ou por pulverização, em provetes de argamassa de cal aérea ou pedra de Malta saturados com soluções salinas de cloreto de sódio ou sulfato de sódio a 10% (percentagem ponderal). Foi efectuada uma análise macroscópica do efeito dos dois modificadores, baseada em ensaios de secagem. A pesquisa do estado-da-arte incidiu sobre as características dos materiais porosos, transporte de água, sais solúveis e modificadores de cristalização. Na campanha experimental foram ainda realizados ensaios de caracterização da argamassa fresca, da argamassa endurecida e da pedra de Malta utilizadas. Determinaram-se também as características de porosidade, permeabilidade ao vapor de água, tensão superficial e evaporação das soluções, capilaridade e secagem. O trabalho realizado permitiu conhecer os principais desenvolvimentos recentes sobre modificadores de cristalização e concluir sobre a influência na secagem e a relevância dos dois modos de aplicação testados do ácido cítrico e do ácido fosfocítrico.
Ano: 2010
Número Páginas:
106p.
Autor(es): Cardeira, A.
Keywords: Sulfato de sódio; Secagem; Sais solúveis; Modificadores de cristalização; Materiais porosos; Inibidores de cristalização; Cloreto de sódio; Ácido fosfocítrico; Ácido cítrico
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Controlo e reparação de anomalias devidas à presença de sais solúveis em edifícios antigos
A acção dos sais solúveis é uma causa frequente de degradação dos edifícios antigos, reflectindo-se a vários níveis (e.g., estético, habitabilidade, segurança estrutural). Esta dissertação tem como objectivo efectuar a análise e sistematização de um leque abrangente de práticas actualmente utilizadas para controlo da degradação por sais solúveis. Neste âmbito, foi utilizada a análise documental de bibliografia posterior a 2000 e procedeu-se à análise crítica de métodos de controlo da degradação seleccionados: remoção mecânica de eflorescências; remoção de materiais contaminantes; compressas; remoção electroquímica de sais; microrganismos; modificadores de cristalização; rebocos; controlo ambiental; controlo da humidade ascensional; método do hidróxido de bário. Analisaram-se também algumas medidas práticas para prevenção do risco de ocorrência ou agravamento desta degradação. Adicionalmente, avaliou-se a complementaridade entre métodos, identificando eventuais benefícios de uma acção conjugada. A sistematização das práticas analisadas envolveu o seu enquadramento segundo três abordagens distintas: prevenção, correcção, e mitigação. A dissertação permitiu tirar conclusões sobre: (i) a actuação face à degradação provocada por sais solúveis, a qual deve pautar-se por uma compreensão global do problema; (ii) a importância das medidas preventivas, como meio para evitar os danos e custos associados; (iii) a relevância dos métodos de controlo da degradação, nas vertentes correctiva e de mitigação; (iv) a experiência actual sobre a utilização prática dos métodos em edifícios, designadamente com relação ao número de casos de estudo existentes; (v) a necessidade de uma boa compreensão das práticas referidas, nomeadamente em relação às vantagens e inconvenientes, a qual pode ser facilitada pela sua sistematização.
Ano: 2010
Número Páginas:
83p.
Autor(es): Puim, P.
Keywords: Edifícios antigos; Reabilitação; Degradação; Prevenção; Sais solúveis
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Estudo da camada pictórica na azulejaria portuguesa do século XVII
Estudou-se um conjunto de fragmentos de azulejos datados do século XVII, de produção portuguesa, cedido pelo Museu Nacional do Azulejo. O objectivo foi caracterizar morfológica e quimicamente a camada pictórica da azulejaria portuguesa do século XVII. O estudo utilizou uma abordagem multi-analítica, incluindo a espectrometria de fluorescência de raios X dispersiva de energias (µ-EDXRF), espectroscopia de Raman, o microscópio electrónico de varrimento com microanálise de raios X (SEM-EDS), e técnicas de observação incluindo o SEM e microscopia óptica. A azulejaria portuguesa do século XVII caracteriza-se por uma paleta cromática relativamente rica, que engloba o azul, amarelo, laranja, verde, púrpura, um tom púrpura acastanhado e ainda outro castanho muito escuro utilizado em contornos. As cores integram um fundo branco o vidrado estanífero característico da majólica. Confirmou-se que o azul se deve ao óxido de cobalto, o púrpura ao óxido de manganês e um dos verdes, de aparência transparente, ao óxido de cobre. Os resultados indicam que o amarelo será uma variante do pigmento amarelo de Nápoles (antimoniato de chumbo), constituído por um óxido triplo de Pb-Sb-Zn. As outras cores são obtidas através de misturas: o laranja resulta da adição de hematite ao pigmento amarelo, o verde-seco resulta da adição de óxido de cobalto também ao pigmento amarelo, e os vários tons entre púrpura e castanho resultam da mistura de hematite com óxido de manganês em teores variáveis. Observaram-se morfologias distintas das cores: o amarelo, laranja e castanho-escuro permanecem à superfície do vidrado e conferem-lhe cores opacas. O azul, o verde-cobre e o púrpura difundem no vidrado em profundidade e, por vezes, horizontalmente. Os seus óxidos dissolvem-se na matriz vítrea, obtendo-se uma cor transparente. Com o verde-seco ocorre uma separação dos componentes da cor, na medida em que as partículas de pigmento amarelo permanecem à superfície, enquanto o azul difunde no vidrado.
Ano: 2010
Número Páginas:
41.
Autor(es): Coentro, S.
Keywords: Heritage tiles; Glazed ceramics; Cerâmica vidrada; Composição e morfologia da cor; Análise química; Azul de cobalto; Pigmentos; Azulejos históricos
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Utilização de hidrófugos de superfície em materiais cerâmicos. Influência na secagem.
A presente dissertação tem por finalidade compreender a influência dos tratamentos hidrófugos na secagem do tijolo cerâmico, tendo assentado na realização de ensaios de absorção capilar, permeabilidade ao vapor de água e secagem. Foi inicialmente avaliada a possibilidade de utilização de tijolo cerâmico maciço de três proveniências distintas. Uma destas origens foi a Praça de Touros do Campo Pequeno, em Lisboa, que permitiu estudar quatro tipos distintos de tijolo antigo. As outras duas origens foram as cerâmicas Torreense e de Vale de Gândara, tratando-se portanto neste caso de tijolos de fabrico recente. Os diferentes tipos de tijolo foram caracterizados quanto à sua aparência, morfologia, teor de sal, absorção capilar e comportamento em secagem. O tijolo de Vale de Gândara foi o tipo seleccionado para a aplicação dos tratamentos hidrófugos. Foi detectada a presença de fissuras neste tipo tijolo, tal como em todos os outros tipos caracterizados. Sendo este defeito relevante para o transporte de humidade, foi necessário ter em consideração a influência da orientação preferencial das fissuras. Assim, utilizaram-se em todos os ensaios provetes com fissuras paralelas e provetes com fissuras perpendiculares à superfície. Estudaram-se cinco tratamentos hidrófugos com base em silicone. Foram realizados ensaios de absorção capilar através da face tratada, ensaios de permeabilidade ao vapor de água e ensaios de secagem (método RILEM da curva de evaporação). Realizaram-se ensaios semelhantes sobre o material não-tratado, que serviram como referência. Os resultados do ensaio de absorção capilar indicam que a eficácia de quatro dos tratamentos é elevada, sendo a secagem do tijolo significativamente dificultada por esses quatro produtos. Verificou-se, no entanto, que o decréscimo da permeabilidade ao vapor apenas é significativo para três hidrófugos. A influência dos hidrófugos na permeabilidade ao vapor apenas é mensurável no caso dos provetes com fissuras paralelas à base. Quando as fissuras são perpendiculares à base, a permeabilidade ao vapor é bastante mais elevada, não sendo afectada pelo hidrófugo.
Ano: 2010
Número Páginas:
170.
Autor(es): Couto, S.
Keywords: Edifícios antigos; Materiais porosos; Tratamentos superficiais; Humidade; Secagem; Tijolos; Materiais cerâmicos; Hidrófugos
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Influência dos revestimentos por pintura na secagem do suporte
A presente dissertação visa compreender a influência dos revestimentos por pintura na secagem de materiais de construção porosos, tendo focado a nível experimental o caso dos substratos constituídos por uma argamassa de cal aérea. Aborda-se, em particular, o caso dos edifícios antigos e, mais especificamente, a situação das paredes com teor de humidade não desprezável que é muito corrente neste tipo de edifícios. O levantamento do estado-da-arte incide sobre as características dos materiais porosos, em particular as argamassas de cal aérea, e de diferentes tipos de revestimentos por pintura indicados para este tipo de utilização. Foca também os mecanismos de transporte de humidade envolvidos nos processos de secagem. Efectuou-se uma pesquisa de mercado e um inquérito ao meio técnico com o objectivo de perceber quais os revestimentos por pintura usados em intervenções de reabilitação / conservação e, assim, avaliar a situação da prática em Portugal. A campanha experimental a seguir realizada incluiu ensaios de permeabilidade ao vapor de água, de absorção capilar e de secagem e incidiu sobre dezasseis revestimentos por pintura disponíveis no mercado português. Treze destes revestimentos são tintas de silicatos, de silicone ou de pliolite que os respectivos fornecedores indicaram serem apropriadas para aplicação em paredes com problemas de humidade. Ensaiaram-se ainda duas tintas de cal de fabrico industrial e uma tinta plástica que serviu como referência. A dissertação permitiu obter dados sobre o estado-da-prática em Portugal, em particular no que se refere aos tipos de tintas usados em paredes de edifícios antigos com teor de humidade não desprezável. Permitiu também retirar conclusões sobre: (i) a influência dos revestimentos por pintura na secagem, na absorção de água por capilaridade e na permeabilidade ao vapor de água; (ii) a influência que o estado de humidificação do suporte pode ter no comportamento dos revestimentos; (iii) a correlação existente entre o comportamento à secagem (índice de secagem) e a permeabilidade ao vapor de água, que é a característica correntemente utilizada para prever o desempenho dos revestimentos.
Ano: 2009
Autor(es): BRITO, Vânia
Keywords: Transporte de humidade; Argamassas de cal; Secagem; Materiais porosos; Edifícios antigos; Tintas de cal; Tintas de pliolite; Tintas de silicone; Tintas de silicato; Revestimentos por pintura
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Relatórios
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Guia Português para Auditorias Pré-Demolição
A realização de auditorias pré-demolição a edifícios requer o envolvimento de várias partes interessadas, desde o proprietário, ao projetista e ao empreiteiro, com vista a maximizar a recuperação de materiais e elementos construtivos e minimizar a quantidade de resíduos de construção e demolição, de modo a impulsionar a economia circular no setor da construção. Estas auditorias devem ser realizadas antes do projeto de demolição ou reabilitação do edifício, de acordo com recomendações comuns. Para a realização dessas auditorias, foi desenvolvido este Guia Português para Auditorias Pré-Demolição e uma ferramenta em Excel com modelos padrão para a realização de um inventário aos recursos presentes no edifício. O inventário teve como base as orientações da União Europeia e do Quadro comum da União Europeia de Edifícios Sustentáveis
Ano: 2023
Autor(es): Vieira, M.; Rezvani, S.; Couto, P.; Salvado, A.; Falcão Silva, M. J.; Martins, I. M.
Keywords: Valorização; Resíduos de construção e demolição; Reciclagem; Reutilização; Economia circular; Auditorias pré-demolição; Guia
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Auditorias de pré-demolição - Enquadramento concetual
Os resíduos de construção e demolição (RCD) representam 46% do total de resíduos produzidos na Europa, cerca de 820 milhões de toneladas por ano, ou 5190 kg per capita. Vários constituintes dos RCD são potencialmente reutilizáveis e recicláveis, o que foca a atenção no seu papel relevante na promoção dos princípios da economia circular no setor da construção, na fase de fim de vida. Este enquadramento conceptual visa reunir as melhores práticas dos diferentes países relativamente à aplicação de auditorias de pré-demolição em edifícios como uma ferramenta útil para o desenvolvimento do guia português. É também abordada a necessidade de minimizar a geração de resíduos contaminados, durante a demolição ou reabilitação de edifícios, como um caminho relevante para maximizar a reutilização e reciclabilidade dos RCD e a qualidade dos materiais recuperados. Para este efeito, é apresentada uma lista de substâncias perigosas críticas e feita a identificação dos materiais de construção que potencialmente contêm constituintes perigosos. Neste relatório é descrita a atividade desenvolvida na tarefa T2
Ano: 2022
Autor(es): Rezvani, S.; Salvado, A.; Falcão Silva, M. J.; Martins, I. M.
Keywords: Gestão de recursos; Resíduos de construção e demolição; Valorização; Reciclagem; Reutilização; Economia circular; Auditorias de pré-demolição
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Betão de elevada densidade com agregados de minério de ferro de Moncorvo
Foi fabricado um betão com agregados de minério de ferro proveniente de jazida de Moncorvo, para avaliação do potencial destes agregados para o fabrico de betão de elevada densidade. Com base nos resultados obtidos são feitas considerações sobre a densidade do betão que será possível obter em função da massa volúmica do agregado.
Ano: 2017
Autor(es): Ribeiro, A. C.
Keywords: Agregado de elevada densidade; Minério de ferro; Betão de elevada densidade
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DRYMASS Drying of porous building materials possibly contaminated with soluble salts (PTDC/ECM/100553/2008): Final Report
The research project DRYMASS Drying of porous building materials possibly contaminated with soluble salts (PTDC/ECM/100553/2008) took place from February 2010 to January 2014. The project allowed advancing the knowledge on drying of porous building materials, as well as about how soluble salts and some types of surface layers affect that behaviour. A new method to characterize salt decay processes by optical profilometry was proposed, and the usefulness of NMR to clarify the causes of such processes demonstrated. There was also a provisional patent application, which was based on research results about the influence that lime coatings have on drying. The main findings of the project were specifically the following. Lime coatings may accelerate the drying of porous substrates. Also due to their high drying rate, ordinary building materials have a high evaporative cooling potential. With salt solutions, the drying kinetics of porous building materials is slower than with pure water. One of the causes is the reduction in sorptivity. Occasionally, there is also obstruction to vapour transport by the efflorescence. However, in most cases, porous efflorescence occurs, which pose no obstruction to this transport. Further, fissures or disaggregation may accelerate drying. Soluble salts amplify the effects that the natural heterogeneity of porous materials has on the drying kinetics. Due to the chaotic nature of the process, lime coatings will not necessarily enhance drying in this case. Sodium sulfate can be very destructive in the absence of high temperature or successive wet/dry cycles. A delamination pattern similar to those found in real constructions was observed on the well-known Ançã limestone. NMR showed that mirabilite and heptahydrate can both be responsible for this delamination pattern, in different conditions. Thermal expansion may be one of the mechanisms involved in salt decay processes.
Ano: 2014
Número Páginas:
35.
Autor(es): Gonçalves, T. D.
Keywords: Final report; Fct; Research project; Soluble salts; Porous building materials; Drying
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Influence of nano-lime and nano-silica consolidants in the drying kinetics of three porous building materials
In this report we describe an experimental study carried out at LNEC within the research project DRYMASS (ref. PTDC/ECM/100553/2008). The study was aimed at evaluating the possibility of increasing the drying rate of porous building materials by means of nano-treatments. It was justified by previous results of other authors that observed an apparently unexplainable increase in the evaporation rate of natural stone after application of nano-calcium hydroxide solutions as consolidating agents. Two commercial treatments, consisting on alcoholic or aqueous suspensions of nano-lime or nanosilica, respectively, were tested on three porous building materials. The treatments are generally used for consolidation. The materials were a lime mortar and two natural stones (Ançã limestone and Bentheimer sandstone). It was concluded that neither of the nano-treatments hinders drying. However, they were also not able to increase the drying kinetics of any of the three substrates.
Ano: 2014
Número Páginas:
24pp.
Autor(es): Musacchi, J.; Gonçalves, T. D.
Editor: LNEC
Keywords: Porous materials; Drying; Nano sílica; Nano-lime
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The altertion kinetics curve and time-lapse imaging - Useful features in salt crystallization tests
The decay of porous building materials due to salt crystallization is very frequent and often significant in the built heritage and, thus, a proper understanding of the underlying processes has major importance for conservation. In this light, a new method for characterization of salt decay processes was developed within the DRYMASS research project, which is based on continuously measuring by optical profilometry the micrometric changes that occur on the material surface during drying. This method produces three different types of output: the so-called "alteration curve", as well as the current gravimetric evaporation curve and time-lapse photographs of the decay. But the three features had, until now, to be recorded using different specimens. This is an important limitation because the high uncertainty of salt decay processes may give rise to different decay patterns in similar specimens. Here, we present a development of the original study, which was afterwards carried out within the same project to allow evaluating the three features in a single specimen, by using an integrated set-up. This new study was carried out with two salts often found in salt decayed constructions, Na2SO4 and NaCl, and a material frequently used in the architectural heritage, Ançã limestone. Some of the experiments were performed after application of a water repellent treatment on the stone.
Ano: 2014
Autor(es): Musacchi, J.; Gonçalves, T. D.
Keywords: Time-lapse photography; Optical profilometry; Drying curve; Alteration curve; Crystallization tests; Drying; Crystallization; Soluble salts
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Report Year 3 of the Drymass research project
This is the third progress report of the research project "DRYMASS - Drying of porous materials possibly contaminated with soluble salts". It includes the following main sections: (i) A summary of the work, which briefly describes the activities undertaken in the reporting period and the results achieved, referring specifically to the tasks under execution in that period. (ii) A justification of the deviations from the Approved Proposal, both from a scientific or financial viewpoint. It also identifies the major difficulties in implementing the approved work plan, and how they will be overcome. (iii) A list of publications. It includes also the following annexes: Annex I 2nd reformulation proposal with updated timeline; Annex II Cryspom III - Book of abstracts and conference program; Annex III Summary report on Cryspom III; Annexe IV Figures and abstracts; Annexe V Article submitted to Transport in Porous Media.
Ano: 2013
Número Páginas:
143p.
Autor(es): Gonçalves, T. D.
Editor: LNEC
Keywords: Drying; Soluble salts; Drymass project; Progress report
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Some conceptual tools for deciding and planning in built heritage conservation
Conserving the built heritage today entails decisions and planning at several different levels. Firstly, analysis is necessary regarding what to conserve: values, authenticity and integrity are the key concepts at this macro level. Then, decisions on how to conserve them should consider the chief principles of good conservation practice, among which compatibility, retreatability and minimum intervention are prominent today. This report analyses these concepts and the different ways in which they were translated into the decision support systems that are nowadays resorted to, from values-based decision making and risk management in conservation to intervention planning and performance assessments. The ultimate goal of this analysis is to compile tools that promote a more rational decision making in conservation.
Ano: 2013
Número Páginas:
137pp.
Autor(es): Revez, M. J.
Editor: LNEC
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Resíduos de construção e demolição - Atividade desenvolvida no LNEC
Este relatório sintetiza a atividade desenvolvida no LNEC visando contribuir para a aplicação dos materiais obtidos no processamento de resíduos de construção e demolição (RCD) no sector da construção, nomeadamente em betões e argamassas, em pavimentos rodoviários e em aterros e camadas de leito de infraestruturas de transporte. Esta atividade abrange as áreas de investigação programada, de investigação por contrato e outras atividades científicas e técnicas das quais se destaca a preparação de especificações técnicas específicas para estes materiais, a difusão de conhecimentos através da realização de ações de formação, da elaboração de documentos e da participação em conferências e outras reuniões científicas e técnicas. Nesta atividade integra-se também a cooperação com entidades, nacionais e estrangeiras, designadamente com universidades e associações de carácter científico e técnico. Sendo esta uma atividade transversal no LNEC O presente relatório integra o trabalho desenvolvido no Departamento de Materiais, no Departamento de Edifícios, no Departamento de Geotecnia e no Departamento de Transportes.
Ano: 2012
Número Páginas:
35pp.
Autor(es): Martins, I. M.; Veiga, M. R.; Roque, A. J.; Freire, A. C.; Batista, F. A.; Fortunato, E.
Editor: LNEC
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AVALIAÇÃO DA DEGRADAÇÃO DO BETÃO ARMADO DOS VIADUTOS ENTRE OS POSTOS DE ACOSTAGEM 4/5 E 9/10 DA APS
A empresa Repsol Polímeros, Lda, através de correio electrónico no dia 6 de Abril de 2011, solicitou ao Laboratório Nacional de Engenharia Civil (LNEC) a avaliação do estado de degradação de estruturas do Terminal Portuário do Porto de Sines, que incluíam dois viadutos localizados entre os postos de acostagem 4/5 e 9/10 da Área do Porto de Sines (APS)1 e o porto-cais do terminal de Graneis Líquidos2, e a apresentação de recomendações relativas à solução a adoptar para a recuperação das estruturas.
Ano: 2011
Número Páginas:
46p.
Autor(es): Ribeiro, M. S.; Monteiro, A.
Editor: Divisão de Divulgação Científica e Técnica - LNEC
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Informações Científicas e Técnicas
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Vocabulário ilustrado da degradação dos azulejos históricos
O Laboratório Nacional de Engenharia Civil tem vindo a desenvolver um estudo no domínio da conservação dos azulejos históricos que permitiu, nalguns casos relevantes, estabelecer uma ligação entre determinados defeitos de fabrico e formas específicas de degradação. Esse estudo demonstrou a conveniência no estabelecimento de um glossário ilustrado, incluindo defeitos de fabrico e formas de degradação e contemplando alguma terminologia nova. É esse trabalho, saído de uma colaboração com o Museu Nacional do Azulejo, que agora se apresenta num vocabulário que inclui também algumas definições básicas, cobrindo termos necessários às definições subsequentes de defeitos de fabrico e de formas de degradação. Os termos em relação aos quais pareceu aos autores poderem subsistir dúvidas têm anexas ilustrações exemplificativas.
Ano: 2011
Número Páginas:
41pp.
Autor(es): Mimoso, J.; Esteves, L.
Editor: LNEC
Keywords: Pt; Vocabulário técnico; Defeito de material de construção; Degradação de material de construção; Património histórico; Azulejo
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Outros
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Betões - Metodologias para prevenir reações químicas expansivas de origem interna
N/A
Ano: 2022
Autor(es): entidade LNEC
Keywords: Especificação; Betão; Expansão do betão; Reação sulfática interna; Reações alcalis-agregado
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Betões - Pozolanas especificações para uso no betão
N/A
Ano: 2022
Autor(es): entidade LNEC
Keywords: Especificação; Betão; Norma; Agregados; Pozolana
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Betões - Avaliação da conformidade do recobrimento das armaduras
N/A
Ano: 2021
Autor(es): entidade LNEC
Keywords: Especificação; Marca de conformidade; Inspeção; Betão; Recobrimento de armaduras
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Betões - Guia para a classificação de superfícies de betão à vista
N/A
Ano: 2021
Autor(es): entidade LNEC
Keywords: Especificação; Betão aparente; Betão armado; Superfícies de betão
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Planning Perspectives and Approaches for ActivatingUnderground Built Heritage
This paper delivers actionable recommendations towards building a rationale for activating and promoting Underground Built Heritage (UBH) based on the nexus heritage, territory and society, and making use of existing literature and findings from five international cases. The research was conducted in the framework of the working group on Planning Approaches of the COST Action Underground4value. The analysis of the cases aims to provide guidelines for this working group and to benchmark good practices in activating UBH. It highlights the importance of community-led initiatives, leadership and dialogue and power sharing between the local/regional authorities and communities aiming for better understanding of the potential of UBH. The successes and/or failures of the five cases emphasise the importance of knowledge and experience in participatory approaches. Success was verified, when effectiveness and democratic principles were combined in the planning process, and local history is integrated with citizen science, co-creation and placemaking. The analysed approaches stimulate a new hybrid layer for activating UBH, provide mechanisms of mediation between people and heritage, and contribute to cultural and social dimensions of sustainability. This is a highly challenging endeavour, as it seeks to support and advance a sound understanding of UBH as a sustainable resource, backed by strategic stakeholder dialogue and contextual knowledge. Such effort requires a dynamic understanding of UBH values, knowledge, abilities and skills, towards creating more effective coalitions of actors within localities, by developing structures, which encourage long term collaborative relationships.
Ano: 2021
Número Páginas:
15p.
Autor(es): Costa, C.; Menezes, M.; Ivanova-Radovanova, P; Ruchinskaya, T.; Lalenis, K.; Bocci, M.
Revista: Sustainability
Editor: MDPI
Volume:
13(18).
Keywords: public participation; place and citizen-based approaches; placemaking; underground heritage
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Betões - Determinação da permeabilidade ao oxigénio
N/A
Ano: 2019
Autor(es): entidade LNEC
Keywords: Especificação; Betão endurecido; Oxigénio; Ensaio de betão; Permeabilidade do betão
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Materiais históricos: entre tradição e inovação
A caracterização dos materiais históricos e a identificação do respetivo estado de conservação engloba um corpus de conhecimento teórico, prático e metodológico essencial para a conservação e o restauro do património cultural arquitetónico e arqueológico. Refletir sobre os materiais históricos para intervir no património requer, pois, contemplar a variedade de materiais a partir das suas múltiplas facetas, reivindicando uma perspetiva pluri e interdisciplinar na elaboração do conhecimento científico. Requer também aprofundar o estudo das tecnologias e materiais tradicionais, o que contribui para densificar o campo de conhecimento sobre o património e, cientificamente, definir os requisitos de compatibilidade e eficiência dos novos materiais, paralelamente colaborando para a salvaguarda do saber técnico tradicional.
Ano: 2019
Autor(es): Menezes, M.; Santos Silva, A.
Keywords: Congress; istoric heritage; Archeological heritage /; Architectural heritage; Cultural heritage; Heritage conservation; Materials conservation; Construction material; Cngresso; Património histórico; Património arqueológico; Património arquitetónico; Património cultural; Conservação de património; Conservação de materiais; Material de construção
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PATRIMA_2016
O artigo trata de uma síntese de resultados do Congresso Ibero-Americano Património, suas matérias e imatérias, LNEC, Lisboa, 2-3 de novembro de 2016, constituindo-se um artigo de noticías.
Ano: 2017
Número Páginas:
1p.
Autor(es): Menezes, M.; Costa, D.; Mimoso, J.
Revista: Pedra & CAL
Editor: GECoRPA - Grémio do Património
Volume:
61.
Keywords: Resultados; PATRIMA; Congresso Ibero Americano
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Prefácio do Livro "A supremacia do Pedestre"
O tabalho faz uma apresentação crítica do Livro " A supremacia do Pedestre", da autoria de Fábio Fonseca e Antonio Colchete Filho, tendo o Livro sido editado pela UNALFA: Editora da Unviersidade FEderal de Juiz de Fora, Minas Gerais, Braisl.
Ano: 2016
Autor(es): Menezes, M.
Keywords: Urbanismo; Planeamento; Cidades criativas; Calçadão; Pedestre
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Determinação do teor de cimento numa amostra de betonilha
É analisada uma amostra de betonilha para determinação do teor de cimento. As análises incluíram a realização de ensaios de resistência à compressão, termogravimetria e químicos.
Ano: 2014
Autor(es): Ribeiro, A. C.; Santos Silva, A.
Keywords: Resistência à compressão; Teor de cimento; Análise termogravimétrica; Ensaios químicos; Caraterização; Betonilha
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