Qualidade do ar em zonas industriais – Caso de estudo do Barreiro

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de MestreA influência do sector industrial na qualidade do ar ambiente pode ser avaliada através de diversos poluentes, nomeadamente o dióxido de enxofre (SO2) e o dióxido de azoto (NO2). Embora este último seja predominantemente associado ao tráfego rodoviário, a ocorrência em ambientes industriais de concentrações elevadas de SO2 é por vezes também acompanhada por um aumento dos níveis de NOx resultantes de processos de combustão. Neste trabalho avaliou-se o caso de estudo da zona Industrial do Barreiro. Apesar de grande parte do tecido industrial neste concelho ter sido desactivado, permanecem em funcionamento diversas unidades que continuam a ser importantes em termos de emissões. Tal facto conduz a que este seja o único local da Região de Lisboa e Vale do Tejo onde se registaram excedências aos valores-limite legislados para o SO2, tendo em conta o diagnóstico da situação em termos de qualidade do ar. A avaliação da distribuição espacial de SO2 e de NO2 permitiu identificar as zonas de maiores concentrações destes poluentes (junto às fontes pontuais no caso do SO2 e nas áreas mais urbanas no caso do NO2). O trabalho efectuado permitiu também avaliar a área de representatividade de três estações de monitorização da qualidade do ar geridas pela Comissão de Coordenação e Desenvolvimento Regional de Lisboa e Vale do Tejo em funcionamento na área em estudo, bem como complementar o conhecimento obtido através desta rede de monitorização

Bond and flexural behavior of concrete elements strengthened with NSM CFRP laminate strips under fatigue loading

This paper presents the results of an experimental research on bond and flexural behavior of concrete elements strengthened with carbon fiber reinforced polymer (CFRP) laminate strips under fatigue loading conditions, applied according to the near-surface mounted (NSM) strengthening technique. Long-term performance of the NSM system could be compromised by fatigue loading, which may result in deterioration and weakening of individual components (steel, FRP, concrete), or loss of bond performance and composite action. Hence, an experimental program composed of direct pullout tests and slab specimens was carried out to evaluate the influence of the stress level and amplitude of cycles imposed to the specimens. In bond fatigue tests, debonding failure occurred for a maximum stress level corresponding to 60% of the ultimate bond load obtained from monotonic loading. The fatigue loading imposed on the slabs did not yield to its failure. Consequently, the load carrying capacity obtained from post-fatigue tests of strengthened slabs was not significantly affected by this action.This work is supported by FEDER funds through the Operational Program for Competitiveness Factors - COMPETE and National Funds through FCT - Portuguese Foundation for Science and Technology under the project CutInDur PTDC/ECM/112396/2009. The authors also like to thank all the companies that have been involved supporting and contributing for the development of this study, mainly: S&P Clever Reinforcement Iberica Lda., Casais - Engenharia & Construcao S.A., Artecanter - Industria de Transformacao de Granitos, Lda., Tecnipor - Gomes & Taveira Lda., Vialam - Industrias Metalurgicas e Metalomecanicas, Lda., Hilti Portugal-Produtos e Servicos, Lda., Novo Modelo Europa, S.A., Sika Portugal - Produtos Construcao e Industria, and S.A., Cachapuz - Equipamentos para Pesagem, Lda. The first and second authors wishes also to acknowledge the Grants SFRH/BD/80338/2011 and SFRH/BD/89768/2012, respectively, provided by FCT

A new methodology for assisting quality control of NSM-CFRP systems since very early ages

The performance of NSM systems directly depends on the performance of the adhesive which can only be reached if a proper curing conditions and time are assured. In order to assess the curing process of the adhesives, as well as the corresponding bond behavior, adequate non-destructive testing approaches are required. Nonetheless, scarce information could be found in the literature in concern to this relevant topic. To fill such gap, the present paper proposes a new method for continuous quality control of epoxy adhesives, based on adaptations of an existing technique originally devised for continuous monitoring of concrete E-modulus since casting, called EMM-ARM (Elasticity Modulus Monitoring through Ambient Response Method). This work reports the simultaneous study of the adhesive through EMM-ARM, together with direct pullout tests at several ages on concrete specimens strengthened with NSM CFRP laminate strips using the same epoxy. The tests are described, and the obtained results are presented and discussed, highlighting the potential of applying EMM-ARM for quality control and decision-making assistance of NSM systems.FCT -Fuel Cycle Technologies(undefined

Fluência e durabilidade de elementos de betão armado reforçados com laminados de cfrp pela técnica NSM

O presente trabalho teve como objetivo avaliar o efeito da fluência no comportamento a longo prazo e durabilidade de estruturas de betão armado reforçadas com laminados de CFRP de acordo com a técnica NSM. Para tal foi desenvolvido um programa experimental constituído por lajes e ensaios de arranque em flexão, todos sujeitos a um carregamento constante e às seguintes condições ambientais: (i) ambiente de laboratório; (ii) imersão em água; (iii) imersão em água com NaCl; e, (iv) ciclos molhagem/secagem em água com NaCl. Nos ensaios de arranque verificou-se que o efeito de fluência na resistência mecânica foi praticamente negligenciável. As lajes apresentaram um efeito de fluência pronunciado, apesar de este ter sido desacelerado para os ambientes envolvendo submersão

Comportamento à fadiga de elementos de betão reforçados através de sistemas NSM CFRP

O presente trabalho tem como objetivo principal contribuir para o conhecimento do comportamento a longo prazo de estruturas de betão reforçadas de acordo com a técnica NSM (Near-Surface Mounted). O comportamento a longo prazo das estruturas reforçadas é afetado pelas condições ambientais, tais como gelo/degelo, ciclos térmicos, exposição a agentes químicos agressivos e radiação ultra violeta. Além disso, o comportamento estrutural pode ser comprometido pela ações físicas, tais como a ocorrência de carregamentos repetidos que conduzam à fadiga. Destas ações podem resultar a deterioração e enfraquecimento do desempenho dos componentes (aço, FRP, betão), ou perda das propriedades da ligação e ação compósita. Para avaliar esta problemática foi desenvolvido um programa experimental composto por ensaios de arranque direto e de lajes submetidas a ensaios flexão, tendo-se investigado o comportamento da ligação (aderência) e o comportamento à flexão de sistemas de reforço NSM CFRP sob ação de carregamentos cíclicos. O nível de tensão aplicado e a amplitude dos ciclos de carga foram os principais parâmetros em estudo neste trabalho.The present paper aims to contribute to the knowledge of the long-term performance of concrete structures strengthened with the Near-Surface Mounted (NSM) technique. The long-term behavior of strengthened structures is affected by environmental conditions, such as freeze-thaw and temperature cycling, exposure to aggressive chemical agents and ultraviolet light. Furthermore, the long-term performance of structures can be compromised by physical effects, such the occurrence of repeated loadings that my induce fatigue. These actions can cause deterioration and weakening of individual components (steel, FRP, concrete), or loss of bond performance and composite action. Thus, an experimental program was performed, comprising direct pullout tests and testing of slab specimens, in order to assess the bond and flexural behavior of NSM CFRP strengthening system under cyclic loading. Stress level (or fatigue stress) and the amplitude of each cycle were the main investigated parameters

Effects of curing temperature on pull-out behavior and stiffness evolution of epoxy adhesives for NSM-FRP applications

The efficiency of the FRP-concrete strengthening system is strongly influenced by the mechanical properties of the epoxy adhesive, which depend on the curing temperature.In the present work, the influence of temperature on the curing process of the epoxy was examined. Two different temperatures were studied: 20 and 30 °C. The elastic modulus of the adhesive was continuously monitored by using a variant of the classical resonant frequency methods, called EMM-ARM (Elasticity Modulus Monitoring through Ambient Response Method). A simultaneous study of direct pull-out tests with concrete specimens strengthened with NSM carbon FRP laminate strips was carried out at the same two different temperatures to compare the evolution of bond performance with the E-modulus of epoxy since early ages. The results showed that increasing the curing temperature significantly accelerated both the curing process of the epoxy adhesive and the evolution of bond performance. Moreover, the EMM-ARM technique revealed its ability in clearly identifying the hardening kinetics of epoxy adhesives, allowing measurements since very early ages and in different environmental conditions

Quality control and monitoring of NSM CFRP systems: E-modulus evolution of epoxy adhesive and its relation to the pull-out force

The present paper describes the application of an innovative technique (termed EMM-ARM: Elasticity Modulus Monitoring through Ambient Response Method) for continuous monitoring of the stiffening process of an epoxy adhesive used in near-surface mounted (NSM) fibre reinforced polymer (FRP) reinforcements. A simultaneous study of direct pull-out tests with concrete specimens strengthened with NSM carbon FRP laminate strips was carried out to compare the evolution of bond performance with the E-modulus of epoxy since early ages. A relationship between the evolution of epoxy E-modulus and the maximum pull-out force is assessed, highlighting the potential of applying EMM-ARM for quality control and decision-making assistance of NSM systems.This work is supported by FEDER funds through the Operational Program for Competitiveness Factors - COMPETE and National Funds through FCT - Portuguese Foundation for Science and Technology under the projects CutInDur PTDC/ECM/112396/2009 and VisCoDyn EXPL/ECM-EST/1323/2013. The authors also like to thank all the companies that have been involved supporting and contributing for the development of this study, mainly: S&P Clever Reinforcement Iberica Lda., Artecanter - Industria de Transformacao de Granitos, Lda., Vialam - Industrias Metalurgicas e Metalomecanicas, Lda. The first and second authors also acknowledge the grants SFRH/BD/80338/2011 and SFRH/BD/80682/2011, respectively, provided by FCT

Behaviour of concrete elements strengthened with near surface mounted CFRP strips under thermal cycles

The present work intends to contribute for the knowledge on durability performance of the near-surface mounted (NSM) strengthening technique, which is an issue that still requires significant research effort. For that purpose, an experimental program was developed using cubic pullout and slab specimens strengthened with NSM carbon fiber reinforced polymer (CFRP) strips. These specimens were submitted to thermal cycles in order to study the effect of this environmental action on the effectiveness of the NSM technique. The thermal cycles were defined according to the EN 13687-3 standard. After being submitted to this action during up to eight months, the specimens were monotonically tested up to failure using four-point bending and pullout direct test configurations for slabs and cubic specimens, respectively. To compare the performance of these specimens with non-aging ones, control specimens were also tested. The obtained results indicate that the loading capacity of the slabs and damage mechanism were not affected by thermal cycles. Nevertheless, the bond strength increased with the number of thermal cycles. Therefore, these results suggest that the concrete elements strengthened with CFRP NSM technique are not susceptible to temperature in a range of -15°C to 60°C.FCT -Federación Española de Enfermedades Rara

Creep behavior and durability of concrete elements strengthened with NSM CFRP strips

This paper presents an experimental program aimed to better understand durability and long-term deformational performance of concrete structures strengthened with the near-surface mounted (NSM) technique. The conducted experiments include beam pullout specimens and slabs. Both types of specimens were submitted to sustained loads under the following environmental conditions: (i) placed in the laboratory premises; (ii) immersed in a water tank at 20ºC with 0% of chlorides; (iii) immersed in a water tank at 20ºC with 3.5% of chlorides; (iv) submitted to wet/dry cycles at 20ºC with 3.5% of chlorides. The mid-span vertical deflection of the slabs was continuously monitored, whereas the beam pullout specimens had their loaded end slip monitored. Creep, degradation and their relation with temperature were some of the observations pointed out. The effect of creep is practically negligible in the beam pull out tests and the evolution of the loaded end slip was mainly controlled by the environmental temperature at the lab. Nonetheless, the slabs have a pronounced creep effect, despite it has been mitigated when the slabs were submitted in water. The paper presents the general description of the experimental program and the first results pertaining to sustained loadings until ages up 439 days (current state of the process).FCT -Fuel Cycle Technologies(undefined

Efeito de ciclos térmicos e de ciclos gelo/degelo no comportamento estrutural de elementos de betão reforçados com laminados de CFRP pela técnica NSM

O presente trabalho pretende contribuir para o conhecimento da durabilidade da técnica NSM com recurso a laminados de CFRP sob a ação de ciclos térmicos e ciclos gelo/degelo. Assim, foi desenvolvido um programa experimental com recurso a ensaios de arrancamento direto em provetes cúbicos e de flexão em lajes. Os provetes foram submetidos às ações ambientais durante um período de 4 e 8 meses. No final de cada período, os provetes foram ensaiados até à rotura. A lei de ciclos térmicos imposta aos provetes foi definida com base na EN 13687-3:2002, cujo intervalo de temperaturas variou entre -15°C e +60°C. A lei de ciclos gelo/degelo foi definida com base na CEN/TS 12390-9:2006 e a temperatura variou entre -18°C a +20°C. De uma forma geral verificou-se que as ações ambientais impostas não afetaram a capacidade de carga dos provetes reforçados