Influence of casting condition on the anisotropy of the fracture properties of Steel Fibre Reinforced Self-Compacting Concrete (SFRSCC)

Identification of the tensile constitutive behaviour of Fibre Reinforced Concrete (FRC) represents an important aspect of the design of structural elements using this material. Although an important step has been made with the introduction of guidance for the design with regular FRC in the recently published fib Model Code 2010, a better understanding of the behaviour of this material is still necessary, mainly for that with self-compacting properties. This work presents an experimental investigation employing Steel Fibre Self-Compacting Concrete (SFRSCC) to cast thin structural elements. A new test method is proposed for assessing the post-cracking behaviour and the results obtained with the proposed test method are compared with the ones resulted from the standard three-point bending tests (3PBT). Specimens extracted from a sandwich panel consisting of SFRSCC layers are also tested. The mechanical properties of SFRSCC are correlated to the fibre distribution by analysing the results obtained with the different tests. Finally, the stress-crack width constitutive law proposed by the fib Model Code 2010 is analysed in light of the experimental results.This work is part of the research project QREN number 5387, LEGOUSE, involving the companies Mota-Engil, CiviTest, the ISISE/University of Minho and PIEP. The first author would like to thank the FCT for the financial support through the PhD Grant SFRH/BD/64415/2009. The authors would like to express their sincere gratitude and appreciation to Ibermetais, Secil and SIKA, for supplying, respectively, the fibres, the cement and the super-plasticizer, respectively

Assessing the feasibility of impregnating phase change materials in lightweight aggregate for development of thermal energy storage systems

This paper assesses the feasibility of impregnation/encasement of phase change materials (PCMs) in lightweight aggregates (LWAs). An impregnation process was adopted to carry out the encasement study of two different PCMs in four different LWAs. The leakage of the impregnated/encased PCMs was studied when they were submitted to freeze/thawing and oven drying tests, separately. The results confirmed that, the impregnation/encasement method is effective with respect to the large thermal energy storage density, and can be suitable for applications were PCMs cannot be incorporated directly such as asphalt road pavements.The authors acknowledge the funding given by Centre for Coordination and Regional Development Committee (CCDR-C) through the research project CENTRO-07-ST24_FEDER-002020 "Environmentally-Friendly Aeronautical Transport Systems Integrated Program (EFATRAS)", http://efatrasubi.wordpress.com. Supply of Expanded Clay materials by ARGEX - Argila Expandida, S.A and Cork materials by Sofalca - Sociedade Central de Productos de Cortica, Lda are also acknowledged

BIM-based methodology for the seismic performance assessment of existing URM-RC buildings

No abstract available

Impact of Damping Boundaries on the Quality of the Output Signal in Bender Element Experiments

Bender elements are a popular experimental device for the measurement of the small strain shear modulus of geomaterials. Bender elements are easy to use, can be easily installed in most geotechnical devices (e.g., triaxial apparatus, oedometers, and Rowe cells), and yield shear modulus readings that compare well with those obtained from resonant column tests. Typically, bender element tests involve inducing a shear wave at one end of a sample (the input signal) and reading its arrival at the other end (the output signal). However, the wave propagation induced by bender elements is complex, hindering the interpretation of the output signal and inducing considerable uncertainty in the shear modulus readings. Indeed, besides the desirable shear wave, the vibration of the transmitter also generates laterally propagating compression waves, which reflect from the lateral envelope back into the sample and pollute the output signal. This study analyses the effect of lateral boundaries especially conceived to dampen the incoming compression waves on the quality of the output signal. In this context, damping moulds are designed based on computational simulations of the transient dynamics of the wave propagation, to promote an output signal that presents a clearly identifiable arrival of the shear wave, without it being concealed by compression wave pollution. Prototypes of a few promising designs are produced using 3D printing and tested in the laboratory using a benchmark material (Toyoura sand) and a range of input frequencies. The results are compared with those obtained in a conventional setup with no damping moulds

Influence of the zro2 crystalline phases on the nature of active sites in pdcu/zro2 catalysts for the methanol steam reforming reaction-an in situ spectroscopic study

In this work, the electronic properties of the metal sites in cubic and monoclinic ZrO2 supported Pd and PdCu catalysts have been investigated using CO as probe molecule in in-situ IR studies, and the surface composition of the outermost layers has been studied by APXPS (Ambient Pressure X-ray Photoemission Spectroscopy). The reaction products were followed by mass spectrometry, making it possible to relate the chemical properties of the catalysts under reaction conditions with their selectivity. Combining these techniques, it has been shown that the structure of the support (monoclinic or cubic ZrO2) affects the metal dispersion, mobility, and reorganization of metal sites under methanol steam reforming (MSR) conditions, influencing the oxidation state of surface metal species, with important consequences in the catalytic activity. Correlating the mass spectra of the reaction products with these spectroscopic studies, it was possible to conclude that electropositive metal species play an imperative role for high CO2 and H2 selectivity in the MSR reaction (less CO formation)The research leading to these results has received funding from European Research council project SYNCATMATCH (671093) and from Spanish Ministry of Science, Innovation and Universities with the project “I + D + I research challenges (RTI2018-099668-B-C21)”. This work also was financially supported by: Base Funding-UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy—LEPABE-funded by national funds through the FCT/MCTES (PIDDAC); European Union’s Seventh Framework Program (FP/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement no. 303476.Peer reviewe

Desenvolvimento de painel sanduíche multifuncional para a reabilitação sustentável de edifícios porticados de betão armado: caracterização de componentes

Esta comunicação apresenta um trabalho de investigação dedicado ao desenvolvimento de um painel sanduíche compósito multifuncional concebido para a reabilitação estrutural e térmica de edifícios porticados de betão armado construídos em Portugal a partir da década de 1960 e até meados da década de 1980. Este painel é composto essencialmente por três componentes que visam assegurar a multifuncionalidade pretendida, nomeadamente: (i) finas camadas exteriores, de cariz estrutural, em microbetão reforçado com fibras de aço recicladas resultantes do processo de reciclagem de pneus (MBRFR); (ii) núcleo em poliestireno, para assegurar isolamento térmico contínuo ao painel; e (iii) conetores poliméricos reforçados com fibras de vidro (GFRP), para conferir uma adequada conexão entre as diferentes camadas. O presente artigo aborda primeiramente a caraterização mecânica efetuada ao MBRFR (comportamento em compressão e tração) e aos conetores GFRP (ensaios de tração direta), sendo ainda apresentados os testes efetuados para seleção do material de isolamento térmico a adotar na conceção do painel sanduíche em desenvolvimento. Estes testes abrangem a realização de ensaios de corte em elementos compósitos representativos do referido painel, nos quais se fez variar a tipologia de poliestireno adotada para a camada de isolamento, com o objetivo de avaliar a influência que esta camada pode ter nas condições de ligação dos constituintes do painel sanduíche. Os resultados obtidos permitiram tirar conclusões importantes acerca desta influência, revelando que o material e especialmente a superfície de acabamento podem contribuir de forma não-negligenciável para o comportamento estrutural da solução compósitaFundação para a Ciência e Tecnologia (FCT) o apoio financeiro concedido através da bolsa de doutoramento PD/BD/52657/2014, atribuída no âmbito do Programa Doutoral em Construção e Reabilitação Eco-eficientes (EcoCoRe). Agradece-se ainda à FCT o apoio financeiro prestado, nomeadamente no âmbito do projeto PTDC/ECM-EST/2635/2014, e toda a colaboração e apoio prestado pelas empresas Twincon, BVT-Rausch, PreConTech, Danosa/Eurofoam e IberFibra

Projeto SECCLASS: O desenvolvimento de um sistema de classificação da construção com componente de sustentabilidade adaptado ao BIM

O projeto SECClasS – Sustainability Enhanced Construction Classification System – financiado pelo EEA Grants – pretende facilitar a Economia Circular na Construção introduzindo um Sistema de Classificação de Informações sobre Construção otimizado para a Sustentabilidade. Este sistema será orientado para a metodologia BIM e servirá não só a componente de sustentabilidade, mas também os restantes usos BIM, como a gestão do processo BIM, extração de quantidades, compatibilização de especialidades ou planeamento de obra, e todas as fases do ciclo de vida. É objetivo do projeto que o sistema de classificação seja usado pelos profissionais do projeto, construção e responsáveis pela gestão e manutenção de edifícios e outras infraestruturas. Um sistema de classificação permite unificar a terminologia a todas as escalas, facilitando a comunicação, seleção de materiais e componentes, bem como uma avaliação precisa dos impactos dos edifícios ao longo do seu ciclo de vida, com o objetivo de melhorar o desempenho dos edifícios e redução dos resíduos através de ferramentas digitais de gestão e seleção informada dos elementos construtivos. Este trabalho apresenta os frutos do projeto até à data, que incluem a tradução do sistema Uniclass 2015, as primeiras implementações do sistema em pilotos e ambientes de produção, e o trabalho e resultados esperados até à sua conclusão no final de 2022.info:eu-repo/semantics/publishedVersio