Artigos de Revista
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Hygrothermal ageing of pultruded GFRP profiles: Comparative study of unsaturated polyester and vinyl ester resin matrices
The durability of pultruded GFRP composites is critical to their performance in civil engineering applications, for which comprehensive and validated data is limited. To address this issue, this study presents an extensive experimental programme on the effects of hygrothermal ageing on the performance of pultruded GFRP profiles made of two alternative resin systems unsaturated polyester (UP) and vinyl ester (VE) both comprising identical fibre architecture. The ageing environments included immersion in demineralised and salt water at three different temperatures (20°C, 40°C, and 60°C), and continuous condensation at 40°C, for durations up to two years. Physical, viscoelastic and mechanical (tensile, flexural, in-plane and interlaminar shear) properties were assessed after a desorption period. As expected, the VE profile had overall better performance than the UP profile. After 24 months, the highest reductions in tensile strength occurred for water immersion at 60°C, namely 45% and 33% for the UP and VE profiles, respectively. This paper provides a wealth of test data that can be used for degradation models for the prediction of their long-term mechanical property retention.
Ano: 2020
Número Páginas:
106193.
Autor(es): Sousa, J.; Garrido, M.; Correia, J. R.; Cabral-Fonseca, S.
Revista: Composites Part A
Editor: Elsevier Ltd
Volume:
140.
Keywords: Pultrusion; Mechanical testing; Environmental degradation; Polymer-matrix composites (PMCs)
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In-service performance of fiber-reinforced polymer construction used in water and sewage treatment plants
Fibre reinforced polymer (FRP) composites are being increasingly used in the construction sector, especially in corrosion-prone applications. However, there is still a lack of knowledge about their long-term behaviour under real service conditions. This paper presents a study about the in-service performance of FRP constructions, which involved the field inspection of 410 FRP constructions included in 31 water and sewage treatment plants in various locations in Portugal. The analysis of the data gathered in these inspections allowed (i) validating a classification system previously proposed by the authors for anomalies, causes, inspection methods and rehabilitation techniques for FRP constructions; determining (ii) the most common anomalies that occur during their service stage and (iii) their most probable causes; and (iv) predicting the most suitable diagnosis and rehabilitation techniques for each anomaly. Moreover, this study provided a better understanding of the long-term in-service behaviour of FRP constructions when exposed to different environmental conditions. The analysis of the data obtained in the field study allowed identifying the main parameters governing the in-service performance and durability of this type of constructions. The results obtained show that non mechanical anomalies are the most common. As expected, the durability performance is very different in indoor and outdoor constructions, the latter presenting much more frequent and severe anomalies. UV radiation and chemicals are found to be the most aggressive exposure environments. The results obtained also show that visual inspection is the most effective diagnosis method for this type of constructions and that surface cleaning and protection is the most commonly recommended rehabilitation technique.
Ano: 2020
Número Páginas:
04020059.
Autor(es): Castelo, A.; Correia, J. R.; Cabral-Fonseca, S.; Brito, J.
Editor: ASCE
Volume:
34(4).
Keywords: Data Analysis; Rehabilitation; Diagnosis; Causes; Anomalies; Fiber-reinforced polymer (FRP)
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Inspection, diagnosis and rehabilitation systems for all-fibre-reinforced polymer constructions
In the past few decades, the construction industry has been increasingly using fibre reinforced polymer (FRP) materials, due to their advantages in comparison with traditional materials, especially in aggressive environments. However, the information regarding the long-term behaviour of FRP constructions under real service conditions is limited and scattered. In this paper, a system for the inspection, diagnosis and rehabilitation of FRP constructions is presented and validated, providing a standardized and systematic tool for the maintenance of these constructions during their service life. A classification system for the anomalies and most probable causes is first presented. To assist the diagnosis of the anomalies, several in situ non-destructive methods are included in the system, as well as various rehabilitation techniques, able to maintain and/or restore the functionality of FRP elements. Several correlation matrices are proposed, interrelating different anomalies, and relating them with probable causes, and diagnosis and rehabilitation techniques. The system is validated and calibrated through an extensive field campaign of inspections of 410 substructures in 31 facilities. Although developed for FRP profiles and moulded gratings of all-FRP constructions, the system can also be used to inspect FRP components of sandwich or hybrid structures. The implementation of this system supports the inspection activities of a proactive maintenance strategy and, at the same time, the standardization of inspections, resulting in an increase of the effectiveness and objectivity of the actions to be taken upon the occurrence of anomalies in FRP constructions.
Ano: 2020
Número Páginas:
119160.
Autor(es): Castelo, A.; Correia, J. R.; Cabral-Fonseca, S.; Brito, J.
Revista: Construction and Building Materials
Editor: Elsevier Ltd
Volume:
253.
Keywords: Inspection system; Rehabilitation; Diagnosis; Causes; Anomalies; FRP constructions
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Comparative study of the effect of long-term ageing on the behaviour of bitumen and mastics with mineral fillers
This study aims to evaluate the effect of mineral fillers on bitumen ageing. Two different bitumens and four mastics were investigated in the unaged and long-term aged states, based on different properties (consistency, rheology, fatigue resistance and ductility). Mastics stiffened less due to ageing treatment than bitumens, especially with granite filler. However, the results of the performance tests were not definitive regarding the effect of the filler. Aged bitumen showed greater fatigue resistance and higher specific energy of ductile fracture than unaged bitumen, whereas the mastics showed minor variations in the specific energy of ductile fracture with ageing treatment, which is indicative of less ageing, but the fatigue resistance decreased significantly in mastics with one of the bitumens.
Ano: 2019
Número Páginas:
76-89pp.
Autor(es): Carl, C.; Lopes, P.; Sá-da-Costa, M.; Canon Fallaa, G.; Leischner, S.; Micaelo, R.
Revista: Construction and Building Materials
Editor: Elsevier
Volume:
225.
Keywords: Ductility fracture; Fatigue testing; Rheological properties; Ageing; Filler-bitumen interaction; Bituminous mastic
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Durability of adhesively bonded joints between pultruded GFRP adherends under hygrothermal and natural ageing
This paper presents an experimental and numerical study about the durability of adhesively bonded joints between pultruded glass fibre reinforced polymer (GFRP) adherends for civil engineering applications. Single lap joint (SLJ) specimens were manufactured using either epoxy (EP) or polyurethane (PUR) adhesive and exposed to the following hygrothermal and outdoor ageing conditions for up to 730 days: water and salt water immersion at 20 °C and 40 °C, continuous condensation at 40 °C, salt fog spray at 35 ºC, and outdoor ageing in Lisbon, Portugal. At predetermined times, the mechanical behaviour of the SLJs was assessed through shear tests, in a dry condition. Results obtained show that hygrothermal ageing detrimentally affected the failure load and stiffness of the SLJs made with both adhesives, although this degradation was balanced to some extent by post-curing effects and the desorption period. The magnitude of such degradation was not significantly influenced by the immersion media, but was largely affected by temperature. Outdoor ageing did not cause significant changes in terms of stiffness; for both adhesives, ultimate load presented a moderate increasing trend, with cyclic pattern, reflecting the effects of seasonal changes in weather. For both adhesives, failure always initiated in one of the GFRP adherends, regardless of the ageing process. However, ageing seemed to affect the portion of bond area with either (light) fibre-tear or adhesive failure: in EP-GFRP specimens, the area with adhesive failure (initially null) increased due to ageing, while in PUR-GFRP specimens (significant in unaged joints) it decreased. The final part of the paper presents non-linear finite element (FE) models of the SLJs; these models were developed to numerically simulate the mechanical performance of the joints and to estimate the influence of ageing on the bond vs. slip laws that describe the interaction between the GFRP adherends.
Ano: 2018
Número Páginas:
475-488.
Autor(es): Sousa, J.; Correia, J. R.; J. GONILHA; Cabral-Fonseca, S.; J.P. FIRMO; Keller, T.
Revista: Composites Part B
Editor: Elsevier Ltd
Volume:
158.
Keywords: Mechanical behavior; Natural ageing; Hygrothermal ageing; Durability; Single lap joint; Adhesively bonded joint; Epoxy adhesive; Polyurethane adhesive; Pultrusion; GFRP
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Durability of FRP - concrete bonded joints in structural rehabilitation: a review
Fibre Reinforced Polymer (FRP) composites have been the source of an increasing interest in the field of rehabilitation, namely for repair and strengthening of reinforced concrete (RC) structures. One of the most effective techniques comprises externally bonded FRP composites, in which the efficacy of rehabilitation depends considerably on the integrity and durability of the bond established between the FRP and the substrate, which is provided by a structural adhesive. This paper presents a concise review of critical durability issues associated with the structural bond between FRP and concrete for rehabilitation purposes. A number of factors determining the durability of FRP-concrete bonded joints have been identified and grouped into the following categories: materials adhesive and adherends, joint characteristics and in-service conditions. For each of those factors, the main findings obtained in previous studies are summarized and the aspects that need fuarther investigation are outlined.
Ano: 2018
Autor(es): Cabral-Fonseca, S.; Correia, J. R.; Custódio, J.; Silva, H. M.; Sousa, J.; Machado, Â.
Revista: International Journal of Adhesion and Adhesives
Editor: Elsevier
Keywords: Composite; Concrete; Adhesive; Durability
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Effects of thermal cycles on adhesively bonded joints between pultruded GFRP adherends
This paper presents an experimental study about the effects of thermal cycles on adhesively bonded joints between pultruded glass fibre reinforced polyester (GFRP) adherends used in civil engineering structural applications. Single lap bonded joints were produced with two commercial polymeric adhesives - epoxy (EP) and polyurethane (PUR) - and exposed to a mild (Mediterranean) range of thermal variations (-5 °C to 40 °C) for up to 350 cycles in a dry condition. The mechanical performance of the adhesively bonded joints was assessed by means of single lap shear tests. Regardless of the inherent differences between both adhesives, results obtained show that the global effect of thermal cycles on the load vs. displacement response of EP-GFRP and PUR-GFRP joints was similar. For both adhesives, thermal cycles caused considerable reduction of joint stiffness and strength, with maximum reductions of 18% and 22% for EP-GFRP joints, respectively, and 19% and 11% for PUR GFRP joints. The degradation of performance was influenced by post-curing effects, more relevant in the PUR adhesive. Before exposure to thermal cycles, both types of specimens exhibited similar failure mechanisms, which generally (80-90% of cases) involved light fibre tear and fibre tear modes, attesting the effectiveness of the adhesion process and material compatibility. Exposure to thermal cycles did not influence the failure modes of the PUR-GFRP joints; however, EP-GFRP joints became more prone to adhesive failure after being subjected to thermal cycles. Overall, the results obtained indicate that thermal cycles degrade bonded joints between pultruded GFRP adherends; however, for the conditions used in this study, this degradation seems to be compatible with the structural use of this type of joints in civil infrastructure.
Ano: 2018
Número Páginas:
518-529.
Autor(es): Sousa, J.; Correia, J. R.; Firmo, João P.; Cabral-Fonseca, S.; J. GONILHA
Revista: Composite Structures
Editor: Elsevier Ltd
Volume:
202.
Keywords: Durability; Thermal cycles; Adesively bonded joints; Epoxy; Polyurethane; Pultruded GFRP adherends
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Some permanent effects of hygrothermal and outdoor ageing on a structural polyurethane adhesive used in civil engineering applications
This paper presents an experimental study about the effects of hygrothermal and outdoor ageing on a polyurethane (PUR) adhesive used in civil engineering applications. Small scale adhesive coupons were exposed to different types of ageing environments for up to two years: (i) immersion in demineralised water at 20 and 40 °C, (ii) immersion in salt water at 20 and 40 °C, (iii) continuous condensation environment at 40 °C, and (iv) outdoor ageing in Lisbon, Portugal. At predetermined times, after a desorption period until constant mass, the effects of such exposure on the physical and mechanical responses of the PUR adhesive was investigated using the following techniques: (i) water sorption, (ii) dynamic mechanical analyses (DMA); (iii) flexural; and (iv) in plane shear tests. The diffusion mechanisms observed were not purely Fickian; a long relaxation period was noticed, with water molecules being continuously incorporated in the adhesive until the end of the experiments; two alternative analytical modelling approaches were successfully used to simulate the diffusion processes. After immersion in water and salt water for two years, the viscoelastic behaviour of the adhesive showed signs of post-curing phenomena, and some of the physical degradation was found to be reversible due to drying, although it was not explicitly quantified; accordingly, the Tg showed increasing trends (11 14%). The mechanical properties of the adhesive showed signs of irreversible degradation mechanisms, more relevant on the in-plane shear properties, with reductions up to 26% in strength and 44% in modulus under the harsher conditions. Flexural properties also exhibited irreversible degradation, with maximum reductions up to 30% in strength and 36% in modulus. Increased temperature did not have a significant effect in the flexural and shear strength, but caused higher degradation in the corresponding moduli. The degradation caused by salt water immersion and continuous condensation was comparable to that in demineralized water immersion (at the same temperature).
Ano: 2018
Número Páginas:
406-419.
Autor(es): Sousa, J.; Correia, J. R.; Cabral-Fonseca, S.
Revista: International Journal of Adhesion and Adhesives
Editor: Elsevier Ltd
Volume:
84.
Keywords: Outdoor ageing; Hygrothermal ageing; Polyurethane; Structural adhesive; Durability
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Durability of an epoxy adhesive used in civil structural applications
This paper presents an experimental study about the durability of a cold curing structural epoxy (EP) adhesive exposed to different hygrothermal and outdoor ageing environments, typical of civil engineering applications, for up to two years: water and salt water immersion at 20 °C and 40 °C, continuous condensation at 40 °C, and outdoor ageing in a mild Mediterranean climate. After specific exposure periods, changes in the following physical properties and mechanical behaviour of the adhesive were assessed: (i) media diffusion, through water uptake (in hygrothermal environments); (ii) viscoelastic behaviour, through dynamic mechanical analyses (DMA); and (iii) flexural and (iv) in plane shear behaviour. Regarding media diffusion, water uptake did not follow a Fickian behaviour and a final saturation stage was not reached; two alternative non Fickian analytical models were successfully fitted to the test data and the corresponding diffusion parameters were determined. In what concerns the viscoelastic behaviour, while continuous condensation and outdoor ageing caused negligible changes, the Tg of the adhesive generally decreased due to immersion (around 20% in water and 10% in salt water after two years); in addition, at later stages of water immersion, the tan ? curve showed significant shape differences, with the usual curve peak being replaced by two different peaks; a generalised reduction of the storage modulus at the glassy plateau was also noted. In terms of mechanical performance, such plasticization effects were visible in the flexural and shear stress strain behaviours. The flexural properties exhibited irreversible degradation, with the highest reductions (two years of ageing in water at 40 °C) being about 24% and 30% in strength and modulus, respectively. Regarding the shear properties, in hygrothermal environments the shear modulus showed similar decreasing trends to the flexural modulus (43% reduction after one year), but the shear strength increased (~25%); the outdoor ageing affected the shear properties in the same way, but the magnitudes of the changes were lower.
Ano: 2017
Número Páginas:
618-633pp.
Autor(es): Sousa, J.; Correia, J. R.; Cabral-Fonseca, S.
Revista: Construction and Building Materials
Editor: Elsevier
Volume:
161.
Keywords: Outdoor ageing; Hygrothermal ageing; Durability; Epoxy; Structural adhesive
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Creep of sandwich panels with longitudinal reinforcement ribs for civil engineering applications: Experiments and composite creep modeling
N/A
Ano: 2016
Autor(es): Garrido, M.; Correia, J. R.; Keller, T.; Cabral-Fonseca, S.
Revista: Journal of Composites for Construction
Editor: ASCE
Keywords: Glass fiber-reinforced polymer; Polyurethane foam; Composite creep model; Ribs; Composite sandwich panels
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Comunicações
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Environmental degradation of gfrp pultruded profiles made of polyester and vinylester resins
This communication presents preliminary results of a research project on the effects of different environmental agents on the physical, chemical, aesthetical and mechanical properties of glass fibre reinforced polymer pultruded (GFRP) profiles made of either polyester or vinylester resin. In order to study the potential degradation of the two types of profiles in typical environments of civil engineering applications, test specimens are being subjected to the following exposure conditions: (i) immersion in demineralised water, at 23 ºC, 40 ºC and 60 ºC; (ii) immersion in salt-water, at the same temperatures; (iii) continuous condensation at 40 ºC; (iv) salt fog chamber; (v) thermal cycles, from -5ºC to 40ºC; (vi) accelerated weathering fluorescent ultraviolet light apparatus. Additionally, test specimens were placed in the roof of LNEC thereby being subjected to a natural degradation in a controlled environment. At predefined time intervals, batches of test specimens placed in the above mentioned exposure environments are being removed for physic-chemical and mechanical characterization, in order to assess their behaviour. / Nesta comunicação são apresentados os resultados preliminares de um projecto de investigação em que estão a ser avaliados os efeitos da degradação ambiental nas características físico-químicas de perfis pultrudidos de plástico reforçado com fibra de vidro com dois tipos de matriz uma de poliéster e outra de viniléster. Com o objectivo de estudar os eventuais efeitos de degradação nos dois tipos de perfis, quando expostos a condições típicas das aplicações em engenharia civil, foram efectuadas as seguintes exposições em provetes retirados dos perfis: (i) imersão em água desmineralizada, a 23 ºC, 40 ºC e 60 ºC; (ii) imersão numa solução salina, às mesmas temperaturas; (iii) condensação em contínuo a 40 ºC; (iv) câmara de nevoeiro salino; (v) ciclos térmicos, entre -5 ºC e 40 ºC; (vi) envelhecimento artificial acelerado com lâmpadas fluorescentes de radiação ultravioleta. Para além disso, foram expostos provetes no telhado do edifício principal do LNEC, onde ficaram sujeitos a envelhecimento natural. Em intervalos predefinidos, foram efectuados ensaios de caracterização físico-química e mecânica dos materiais, para monitorizar o seu desempenho ao longo do tempo.
Ano: 2009
Número Páginas:
22pp.
Autor(es): Cabral-Fonseca, S.; Correia, J.; Costa, R.; Carreiro, A.; Rodrigues, M. P.; Eusébio, M. I.; Branco, F.
Editor: LNEC
Keywords: Atmospheric corrosion; Thermal degradation; Construction materials degradation; Polyester resin; Reinforced plastic; Glass fibre; Construction profile
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Jornadas da APAL 2009 Qualisteelcoat
N/A
Ano: 2009
Número Páginas:
4p.
Autor(es): Eusébio, M. I.
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Study of the influence of the ageing conditions in the durability of PVC formulations used in outdoor applications
The main purpose of this paper is to present the results of a study intended to assess the durability of stabilized PVC-U for outdoor applications, in form of calendered films and extruded plates. The samples were subject to different ageing conditions and their degradation state were evaluated, using techniques of molecular analysis, namely Fourier transformed infrared spectroscopy (FTIR), as well techniques for evaluation of macroscopic properties, as colorimetry and tensiles tests. The development of formulations, the ageing and the subsequent characterisation were done in LNEC. Therefore, after a brief introduction, this paper presents the experimental part of the study, as regards the composition of samples and the experimental methods of deterioration and characterisation. Subsequently, the results of the study, their interpretation and the final conclusions are also presented.
Ano: 2008
Número Páginas:
35.
Autor(es): Real, L. P.
Editor: LNEC
Keywords: Experimental test; Degradation of construction materials; Ageing of construction materials; Durability of construction materials; Pvc
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Study of the influence of the ageing conditions in the durability of PVC formulations used in outdoor applications
The main purpose of this paper is to present the results of a study intended to assess the durability of stabilized PVC-U for outdoor applications, in form of calendered films and extruded plates. The samples were subject to different ageing conditions and their degradation state were evaluated, using techniques of molecular analysis, namely Fourier transformed infrared spectroscopy (FTIR), as well techniques for evaluation of macroscopic properties, as colorimetry and tensiles tests. The development of formulations, the ageing and the subsequent characterisation were done in LNEC. Therefore, after a brief introduction, this paper presents the experimental part of the study, as regards the composition of samples and the experimental methods of deterioration and characterisation. Subsequently, the results of the study, their interpretation and the final conclusions are also presented.
Ano: 2008
Número Páginas:
44pp.
Autor(es): Real, L. P.
Editor: LNEC
Keywords: Ageing of construction materials; Pvc; Durability of construction materials; Degradation of construction materials
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Degradation studies of PVC films
The outdoor degradation of poly(vinyl chloride) (PVC) products is complex and not completely understood for most of the technical formulations. Furthermore, it is known that the behaviour of such materials is dependent of the photo-oxidation conditions, namely source of radiation, temperature, presence of water and humidity. In the present work, we have used X-ray photoelectron spectroscopy (XPS) to evaluate the influence of different photo-oxidation conditions on the surface degradation of stabilized PVC, low thickness calendered samples (~ 150 ?m). The main objective is the study of the influence of the weathering conditions on the degradation level of stabilized PVC products for outdoor applications trying to go deeper in the understanding of the mechanism of both the degradation and the stabilization of the surface under different environmental conditions, different polymer formulations and different processing methods (extrusion or calendering). Comparisons are made with previous results obtained using colourimetry and infrared spectroscopy. The role of PVC formulation and of radiation source and water were studied using artificial weathering. Results were compared with degradation induced by natural weathering in Lisbon.
Ano: 2007
Número Páginas:
1.
Autor(es): Rego, A. M. B.; A.M. Ferraria; Real, L. P.
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Artificial accelerated weathering of PVC for outdoor applications: The evolution of physical and mechanical properties
The main purpose of this paper is to present the results obtained, during the years 2001 and 2002, from a study developed in LNEC. The object of this study was to assess the synergetic effect of three of the most significant deteriorating climatic agents (radiation, temperature and water) on the evolution of the properties of hard PVC stabilised with titanium dioxide, for outdoor applications. For the purpose, several samples were subject to natural and artificial weathering. Moreover, their physical and mechanical properties were characterised by techniques of analysis and assessment of the surface aspect (colour and brightness), of assessment of the molecular properties by infrared microscopy (MICROFTIR), as well as of determination of the tensile mechanical properties and assessment of the Charpy impact resistance. The paper was both orally presented and by poster at the panel meeting Ageing, Irradiation, Stabilisation of the Congress MoDeSt 2002. Therefore, this publication includes the text of the paper, the poster, as well as the slides from the oral communication. The development of the formulations, the ageing and the subsequent characterisation by colorimetry, brightness, Charpy impact and tension, were done in LNEC. The characterisation by infrared microscopy was performed in the Laboratoire de Photochimie Moleculaire et Macromoleculaire of the University Blaise-Pascal, Clermont-Ferrand, France.
Ano: 2006
Número Páginas:
37 pp.
Autor(es): Real, L. P.; Rocha, A.; Gardette, Jean-Luc
Editor: LNEC
Keywords: Colorimetry; Infrared microscopy; Natural weathering; Mechanical characterization; Physical characterization; Accelerated weathering; Pvc
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Artificial simulated and natural weathering of PVC for outdoor applications: The influence of radiation and water in the evolution of PVC properties
The main purpose of this paper is to present the results obtained, during the year 2003, from a study developed in LNEC. The object of this study was to assess the synergetic effect of two deteriorating climatic agents (radiation and water) on the evolution of the properties of extruded plates made of hard PVC stabilised with titanium dioxide, for outdoor applications. For the purpose, several samples were subject to natural and artificial weathering, their deterioration condition having been characterised by means of techniques of analysis of colorimetry and infrared spectroscopy (FTIR). Initially, only the presentation of a poster titled Artificial and Natural Weathering of Polyvinyl chloride for Outdoor Applications: the Influence of the Radiation and Water on the Evolution of the PVC Properties was scheduled. Nevertheless, upon request from the secretariat of the Congress, the author also presented an oral paper on the same subject, but including experimental results obtained during the year 2004, which were not mentioned in the poster. Similarly, these results, which were obtained by means of surface analysis techniques by Scanning Electron Microscopy (SEM) and by X photoelectron spectroscopy (XPS), were not included in the paper submitted to the Congress. Therefore, this publication includes the text of the paper referring to the poster, which was initially predicted, as well as the slides of the oral communication presented. It also contains a few results obtained in 2004. The development of the formulations, as well as the ageing and the subsequent characterisation by colorimetry, by infrared spectroscopy and by scanning electron microscopy were performed in LNEC. The characterisation by X photoelectron spectroscopy was conducted at the Molecular Chemistry-Physics Centre of the Instituto Superior Técnico (Higher Technical Institute).
Ano: 2006
Número Páginas:
23 pp.
Autor(es): Real, L. P.; Rocha, A.; Gardette, Jean-Luc; Rego, A. M. B.
Editor: LNEC
Keywords: Electronic spectroscopy; Colorimetry; Infrared microscopy; Scanning electron microscopy; Accelerated weathering; Natural weathering; Pvc
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The Influence of Weathering Conditions in the Evolution of Molecular Properties of Poly(Vinyl Chloride) for Outdoor Applications. An Analytical Study Using Techniques of Surface Analysis (SEM and XPS)
The main purpose of this paper is to present the results of a study intended to assess the deterioration condition of extruded hard PVC plates, for outdoor applications. The plates were subject to different ageing conditions, using techniques of surface analysis, namely scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The development of formulations, the ageing and the subsequent characterisation by scanning electron microscopy were done in LNEC. The characterisation by X-ray photoelectron spectroscopy was done at the Centre for Molecular Chemistry-Physics of Instituto Superior Técnico (Higher Technical Institute of Lisbon). Therefore, after a brief introduction, this paper presents the experimental part of the study, as regards the composition of samples and the experimental methods of deterioration and characterisation. Subsequently, the results of the study, their interpretation and the final conclusions are also presented.
Ano: 2006
Número Páginas:
28.
Autor(es): Real, L. P.; Rego, A. M. B.
Editor: LNEC
Keywords: Spectroscopy of photoelectron x; Surface analysis; Electronic spectroscopy; Scanning electron microscopy; Weathering of construction materials; Degradation of construction materials; Pvc
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Validação de programa informático para calibração de um calorímetro diferencial de varrimento e incerteza associada à determinação da entalpia de fusão
Procurou-se com a presente comunicação, apresentar uma metodologia de validação de um programa informático, desenvolvido no NMPC do LNEC especificamente para a calibração de um calorimetro diferencial de varrimento (DSC) e para calcular a incerteza associada à determinação da entalpia de fusão. Assim, após uma breve introdução, a presente comunicação expõe a formulação essencial que serviu de suporte ao desenvolvimento do programa informático referido, descreve os elementos que constituem o procedimento de validação do mesmo, apresenta o processo de estimativa da incerteza de medição e os resultados da análise efectuada.
Ano: 2006
Número Páginas:
21.
Autor(es): Real, L. P.; Ribeiro, A.
Editor: LNEC
Keywords: Fusão; Entalpia; Calorimetria diferencial de varrimento; Incerteza de medição; Software; Calibração; Calorímetro
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Capítulos de Livros
Renovação da Marca de Qualidade Qualicoat, 2011. Inspecção de 14-07-2011 à empresa J. Silva & Cª. - Licença P-822
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Relatórios
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Estação meteorológica do LNEC
No presente relatório apresentam-se os dados meteorológicos do ano de 2019 recolhidos na estaçãometeorológica existente no Núcleo de Materiais Orgânicos do Departamento de Materiais do LNEC, em Lisboa
Ano: 2023
Autor(es): Cabral-Fonseca, S.
Keywords: Ano 2019; LNEC; Dados meteorológicos
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Estação meteorológica do LNEC
No presente relatório apresentam-se os dados meteorológicos do ano de 2020 recolhidos na estaçãometeorológica existente no Núcleo de Materiais Orgânicos do Departamento de Materiais do LNEC, em Lisboa
Ano: 2023
Autor(es): Cabral-Fonseca, S.
Keywords: Ano 2020; LNEC; Dados meteorológicos
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Regras para a concessão de documentos de aplicação a revestimentos por pintura elastoméricos para rebocos de cimento e para betão em superfícies exteriores de edifícios
No presente relatório descrevem-se os procedimentos adotados pelo LNEC, no âmbito do estudo a efetuar para a concessão de um Documento de Aplicação (DA), relativo a revestimentos por pintura elastoméricos para rebocos de cimento e para betão aplicados em paredes exteriores de edifícios. Consideram-se as condições de exposição atmosférica no exterior sem a influência de ações químicas severas. Indicam-se, também, as ações a desenvolver periodicamente para comprovar que continuam reunidas as condições que terão permitido a concessão do DA.
Ano: 2021
Autor(es): Silva, H. M.; Cabral-Fonseca, S.; Rodrigues, M. P.
Keywords: Rebocos de cimento e betão; Superfícies exteriores; Revestimentos por pintura elastoméricos; Documento de aplicação
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Regras para a concessão de Documentos de Aplicação a revestimentos por pintura de base aquosa para superfícies interiores de habitações paredes e tetos
No presente relatório descrevem-se os procedimentos adotados pelo LNEC para a concessão de um Documento de Aplicação (DA) relativo a revestimentos por pintura de base aquosa para aplicação em paredes e tetos de interiores de habitações, sobre superfícies de estuque de gesso, de gesso cartonado, de reboco de cimento ou de betão. Indicam-se, também, as ações a desenvolver periodicamente para comprovar que continuam reunidas as condições que permitiram a concessão do DA.
Ano: 2018
Autor(es): Cabral-Fonseca, S.; Rodrigues, M. P.
Keywords: Paredes e tetos; Superfícies interiores; Revestimentos por pintura; Documento de aplicação
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Estação Meterológica do LNEC Compilação de dados Ano 2016 - Edifício Principal Terraço da Ala Nascente
No presente relatório apresentam-se os dados meteorológicos do ano de 2016 recolhidos na estação meteorológica existente no Núcleo de Materiais Orgânicos do Departamento de Materiais do LNEC, em Lisboa
Ano: 2017
Autor(es): Cabral-Fonseca, S.
Keywords: Ano 2016; Dados meteorológicos; LNEC
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Regras para a concessão de documentos de aplicação a revestimentos por pintura para rebocos de cimento e para betão em superfícies exteriores
No presente relatório descrevem-se os procedimentos adotados pelo LNEC no âmbito do estudo a efetuar para a concessão de um Documento de Aplicação (DA) relativo a revestimentos por pintura para rebocos de cimento e de betão aplicados em superfícies exteriores (tintas não elastoméricas). Consideram-se as condições de exposição atmosférica no exterior, sem influência de ações químicas severas. Indicam-se, também, as ações a desenvolver periodicamente para comprovar que continuam reunidas as condições que terão permitido a concessão do DA. Este relatório constitui uma revisão do relatório do LNEC nº 252/2013-DM/NMO.
Ano: 2017
Autor(es): Cabral-Fonseca, S.; Rodrigues, M. P.
Keywords: Rebocos de cimento e betão; Superfícies exteriores; Revestimentos por pintura; Documento de aplicação
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Estação meteorológica do LNEC - Compilação de dados Ano de 2014 Edifício Principal Terraço da Ala Nascente
No presente relatório apresentam-se os dados meteorológicos do ano de 2014 recolhidos na estação meteorológica existente no Núcleo de Materiais Orgânicos dom Departamento de Materiais do LNEC, em Lisboa
Ano: 2015
Autor(es): Cabral-Fonseca, S.
Keywords: Ano 2014; LNEC; Dados meteorológicos
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Estação meteorológica do LNEC - Compilação de dados ano 2013 Edifício Principal Terraço da ala Nascente
No presente relatório apresentam-se os dados meteorológicos do ano de 2013, recolhidos na estação meteorológica existente no Núcleo de Materiais Orgânicos do Departamento de Materiais do LNEC, em Lisboa.
Ano: 2014
Autor(es): Cabral-Fonseca, S.
Keywords: Ano 2013; LNEC; Dados meteorológicos
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Regras para concessão de documentos de aplicação a produtos de revestimentos de superfícies de madeira em condições de exposição no exterior
No presente relatório descrevem-se os procedimentos adoptados pelo LNEC no âmbito dos estudos para concessão de um Documento de Aplicação (DA) a produtos de pintura para proteção de superfícies madeira, em condições de exposição atmosférica no exterior. Indicam-se também as ações a desenvolver periodicamente para comprovar que continuam reunidas as condições para a concessão do DA.
Ano: 2013
Número Páginas:
26pp.
Autor(es): Rodrigues, M. P.
Editor: LNEC
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Sistemas de tubagem de poli(cloreto de vinilo) não plastificado (PVC-U) destinados à extração de água em profundidade - Critério para avaliação da aptidão ao uso, com vista à concessão de homologação
Nesta publicação apresenta-se o critério presentemente seguido pelo LNEC para concessão de homologação com certificação, bem como posterior controlo periódico da qualidade a sistemas de tubagem de poli(cloreto de vinilo) não plastificado (PVC-U) destinados à extração de água em profundidade. Após uma breve introdução e a definição do objetivo, indicam-se: - Os requisitos para o sistema da qualidade seguido pelo fabricante; - as caraterísticas e as especificações para a matéria-prima constituinte dos tubos e acessórios; - as caraterísticas e as especificações para os produtos finais, designadamente os tubos e as suas uniões; - a classificação das condições de serviço; - as recomendações para a utilização dos produtos, relativamente ao seu transporte e manuseamento, armazenagem e instalação; - os requisitos do LNEC para o autocontrolo do fabricante; - os requisitos de amostragem do LNEC durante as auditorias técnicas ou campanhas de recolha realizadas ao fabricante pelos técnicos do LNEC, no âmbito da concessão e manutenção da homologação.
Ano: 2013
Número Páginas:
27pp.
Autor(es): Real, L. P.
Editor: LNEC
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Informações Científicas e Técnicas
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Estatística de ensaios interlaboratoriais - Tratamento e avaliação de resultados experimentais
Os resultados experimentais, obtidos através da medição de propriedades dos materiais e produtos, requerem tratamento específico e adequado, de forma a garantir a sua qualidade. É por isso muitas vezes necessário recorrer a métodos estatísticos para fazer a análise do tipo de distribuição dos resultados, proceder à deteção de valores suspeitos num conjunto de observações e à eventual rejeição de resultados anómalos. Este tipo de tratamento estatístico é principalmente adequado a ensaios de intercomparação, quer do foro metrológico (comparação de valores de padrões ou materiais de referência, mediante medição efetuada por operadores de diferentes laboratórios metrológicos, com incerteza variável), quer do âmbito dos laboratórios de ensaio. Os ensaios de Comparação Interlaboratorial realizados por laboratórios de ensaio, constituem uma ferramenta de garantia da Qualidade e são utilizados para a validação de métodos de ensaio (incerteza e robustez) e como um meio para a determinação das características de desempenho dos laboratórios, nomeadamente da reprodutibilidade e da repetibilidade. Nesta publicação faz-se uma descrição dos vários parâmetros que devem ser determinados em ensaios interlaboratoriais do tipo Intercomparações com valor de consenso e respetivos métodos de cálculo. A estatística aqui apresentada pode, numa boa parte dos casos, ser também aplicada à análise de resultados de medições experimentais correntes.
Ano: 2015
Autor(es): Real, L. P.
Keywords: Garantia de qualidade; Método estatístico; Ensaio interlaboratorial
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Weathering and polymer degradation - Review article
The main purpose of this Paper is to present a state of the art about weathering and polymer degradation. This review was presented during a training course promoted by the 5th European Weathering Symposium EWS (XXVIIth Colloquium of Danubian Countries on Natural and Artificial Ageing of Polymers), which was held in Lisbon on September 21 - 23, 2011, organised on behalf of CEEES (Confederation of European Environmental Engineering Societies) by the German Management Society for Environmental Engineering GUS (Gesellschaft für Umweltsimulation e.V.) and supported by SOPSAR (Sociedade Portuguesa de Simulação Ambiental e de Avaliação de Riscos), APIP (Associação Portuguesa da Indústria de Plásticos) and LNEC (Laboratório Nacional de Engenharia Civil). The main topics of this review are the weathering of polymers and composites, the determination, simulation and effects of relevant climatic quantities, innovative polymer additives, new test procedures and devices, instrumental methods of analysis to evaluate polymer degradation, recent developments in polymeric materials and composites designed for outdoor applications and methods for service-life prediction.
Ano: 2012
Número Páginas:
135pp.
Autor(es): Real, L. P.
Editor: LNEC
Keywords: Durability of construction materials; Construction materials degradation; Materials construction weathering; Composite materials; Polymer
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Outros
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MILACRIL BRILHANTE (cor branca) e PRIMÁRIO TT - Revestimento por pintura para azulejos em paredes e tetos interiores de habitações
N/A
Ano: 2022
Autor(es): entidade LNEC
Keywords: Documento de aplicação; Revestimento de paredes; Revestimento por pintura; Parede interior; Revestimento de tetos
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Tinta AQUAREPEL (cor branca) - Revestimentos por pintura para paredes exteriores
N/A
Ano: 2022
Autor(es): entidade LNEC
Keywords: Documento de aplicação; Revestimento por pintura; Parede exterior; Revestimento de parede
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Tinta ROBBIFLEX (cor branca) + PRIMÁRIO HIDRO-ARMADURA FIXADOR NG - Revestimento elastomérico por pintura para paredes exteriores de edifícios
N/A
Ano: 2022
Autor(es): entidade LNEC
Keywords: Documento de aplicação; Revestimento de parede; Revestimento por pintura; Revestimento impermeabilizante; Parede exterior
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PROBEX AQUOSO (cor CAMBALA TD 290) - Verniz para madeira em exterior
N/A
Ano: 2021
Autor(es): entidade LNEC
Keywords: Documento de aplicação; Verniz; Revestimento por pintura; Proteção de madeiras; Madeira
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TINTA ACRÍLICA PURA 9G (cor branca) + PRIMÁRIO PLIOMIL AQUOSO - Revestimentos por pintura para paredes exteriores
N/A
Ano: 2021
Autor(es): entidade LNEC
Keywords: Documento de aplicação; Revestimento de paredes; Revestimento por pintura; Parede exterior
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Tinta SUPERLAVÁVEL MATE + Primário ISOSELANTE - Revestimento por pintura para paredes e tetos interiores de edifícios
N/A
Ano: 2021
Autor(es): entidade LNEC
Keywords: Documento de aplicação; Revestimento de paredes; Revestimento por pintura; Parede interior; Revestimento de tetos
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TINTA NOVÁQUA HD + PRIMÁRIO CINOLITE - Revestimentos por pintura para paredes exteriores
N/A
Ano: 2020
Autor(es): entidade LNEC
Keywords: Documento de aplicação; Revestimento por pintura; Parede exterior; Revestimento de parede
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Tinta DYRUSTAR (cor branca) + Primário Aquoso Branco - Revestimento por pintura de base aquosa para paredes e tetos interiores de edifícios
N/A
Ano: 2019
Autor(es): entidade LNEC
Keywords: Documento de aplicação; Revestimento de parede; Revestimento por pintura; Parede interior; Revestimento de teto
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Luso Spray Branco - Produto para marcação rodoviária
N/A
Ano: 2018
Autor(es): entidade LNEC
Keywords: Europa; Termoplástico; Pavimento betuminoso; Marca rodoviária
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MILACRIL BRILHANTE (cor branca) e PRIMÁRIO TT - Revestimento por pintura para superfícies cerâmicas no interior de habitações
N/A
Ano: 2018
Autor(es): entidade LNEC
Keywords: Documento de aplicação; Revestimento de paredes; Revestimento por pintura; Parede interior; Revestimento de tetos
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