Sugar reduction in fruit nectar: comparison of children and adults's perception.

Human beings have an innate preference for sweet products. A cost-effective strategy to reduce sugar intake in the short term is reducing added sugars of processed foods. However, in order to be effective, sugar reduction should not be perceived by consumers. Preference for sweet taste is different in children and adults, which suggests that recommendations for sugar reduction may differ for products targeted at each segment. In this context, the objectives of the present study were to determine children and adults’ difference thresholds for added sugar in grape nectar, and to determine their hedonic perception towards nectars with reduced sugar content.SLACA, 12. De 4 a 7 de Novembro de 2017. Ref. 70421

Incorporação de cinzas de biomassa como substituto do cimento em argamassas

Hoje em dias, as questões ambientais referentes à produção de cimento e à durabilidade do betão são muito importantes. Assim, a utilização de sub-produtos ou resíduos tem sido efectuada com a perspectiva de minimizar os problemas associados ao betão. As propriedades das cinzas volantes de biomassa (CVB) permitem a sua utilização como material pozolânico e bons resultados foram obtidos com a utilização destas cinzas como material substituinte do cimento. Este trabalho apresenta a caracterização das CVB e o seu efeito nas propriedades de argamassas. As cinzas foram caracterizadas em termos químicos e físicos, sendo estudado 3 níveis de substituição (20, 40 e 60%m) do cimento. As propriedades frescas e endurecidas das argamassas foram estudadas. Os resultados mostraram que a trabalhabilidade diminui com o aumento do teor de cinzas e que argamassas com 20% de substituição do cimento apresentam os melhores resultados em termos de resistências mecânicas e absorção de água. Para além disso, a incorporação de CVB diminui a perda de alcalinidade das argamassas, sendo menor essa diminuição quanto maior for o teor de cinzas volantes de biomassa presente nas argamassas. Este estudo mostra que a utilização de CVB conduz a bons resultados nas propriedades das argamassas e que a sua utilização na produção de betão conduz a uma melhoria no desempenho ambiental sem comprometer a durabilidade e a qualidade do betão.Os autores querem agradencer à FCT (Fundação para a Ciência e Tecnologia – Portugal) e ao programa doutoral Eco-ConstructionandRehabilitation por ajudarem no suporte financeiro através da bolsa com a referência PD/BD/52661/2014 e do projecto com a referência UID/MULTI/00308/2013

Valorisation of wood fly ash on concrete

Wood fly ash (WFA) is a waste material produced in power plants as result of forest residues combustion to produce power and heat. In countries like Portugal, this waste is disposed of in landfills. Since this material shows pozzolanic characteristics, several studies have been done to evaluate its use as a construction material. This work shows an overview of some published results about the effect of the utilisation of WFA, as a supplementary cementitious material, on the durability and quality of concrete. The results showed that the increase on the wood fly ash content leads to a negative effect on the concrete properties when compared with a conventional concrete. However, the results showed that the behaviour of wood fly ash concrete is very similar to the coal fly ash concrete, which is the most pozzolanic material used in the world. In terms of durability, it was verified that WFA improved the most of the durability characteristics with the exception of carbonation resistance. However, more experimental analysis needs to be developed in terms of wood fly ash concrete durability. Results suggested that using wood fly ash to replace cement is a valuable sustainable option for concrete production. This manuscript discusses the key factors and attempts to provide new information about the application of the wood fly ash on concrete.The authors wish to thank the Portuguese Foundation for Science and Technology (FCT) and the Eco-Construction and Rehabilitation Doctoral Programme for supporting the PhD scholarship (reference PD/ BD/52661/2014). This work was also financed by FEDER funds through the Competitivity Factors Operational Programme – COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01 – 0145-FEDER – 007633 and through the Regional Operational Programme CENTRO2020 within the scope of the project CENTRO-01 – 0145- FEDER – 000006

Betão auto-compactável eco-eficiente de reduzido teor em cimento com incorporação de elevado volume de cinzas volantes e metacaulino

A produção de betão assume um papel muito importante na indústria da construção uma vez que mais de 10 biliões de toneladas são produzidas anualmente, sendo a indústria do cimento responsável pela emissão de cerca de 7% das emissões de CO2 para a atmosfera. Portanto, a produção de betões auto-compactáveis (BAC) eco-eficientes, contendo baixos teores de cimento na sua formulação, contribuirá para a sustentabilidade das construções devido à redução do uso de cimento portland, ao aproveitamento de resíduos industriais, para além da minimização da energia necessária para a sua colocação e compactação. Neste contexto, o presente trabalho pretende avaliar a viabilidade da produção de BAC com baixos teores de cimento através da determinação das propriedades no estado fresco e endurecido de betões com elevado volume de cinzas volantes (CV) e metacaulino (MK). Para tanto foram formuladas 6 composições de betões tendo como base duas referências fabricadas com 300 e 500 kg/m3 de cimento, sendo analisada a sua substituição por: 60% de CV e 50% de CV mais 20% de MK, além da adição de cal hidratada nestes dois traços com adições. Para avaliar a auto-compactabilidade foram realizados testes de espalhamento, T , Anel-J, Funil-V e Caixa-L, tendo sido determinada a resistência à compressão aos 3, 7, 14, 21 e 28 dias. Os resultados mostraram que é possível produzir BAC com baixos teores de cimento através do recurso a elevados teores de adições minerais, atendendo aos requisitos reológicos para a autocompactabilidade, com resistências moderadas de 25 a 30 MPa

Quality and durability properties and life-cycle assessment of high volume biomass fly ash mortar

The effect of using biomass fly ash (BFA) on the quality, durability and sustainability of mortars was studied. Using high amounts of BFA does not lead to a production of mortars with better performance than a plain cement mortar. However, when BFA is used in small amounts mixed with coal fly ash, mortars with similar compressive strength, to that of a cement mortar, but with less carbonation and with better environmental performance are obtained. Using BFA in the concrete industry can lead to a minimisationof issues related to the high volume fly ash concrete.The authors wish to thank the Portuguese Foundation for Science and Technology (FCT) and the Eco-Construction and Rehabilitation Doctoral Program for supporting the PhD scholarship (reference PD/BD/52661/2014). This work was also financed by FEDER funds through the Competitivity Factors Operational Programme – COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01- 0145-FEDER- 007633 and through the Regional Operational Programme CENTRO2020 within the scope of the project CENTRO-01- 0145-FEDER- 000006.info:eu-repo/semantics/publishedVersio

Effect of biomass fly ash on fresh and hardened properties of high volume fly ash mortars

The objective of this work was to assess the use of biomass fly ash (BFA) as cement replacement material or as an alkalinity source in high volume fly ash mortar and concrete. Mortar formulations were prepared with different types of cement replacement: fly ash from thermal power plants, BFA, a blend of two pozzolans, and small amounts of BFA or/and hydrated lime (HL). Mortar formulations were tested both in the fresh and hardened state. The replacement of cement by the two fly ashes led to a decrease in the mechanical strength. The best strength values were obtained when higher HL content was introduced in mortars, however, mortars with the lower BFA content presented the best results for the majority of the tests. In general, BFA has a similar effect on cementitious mortars to coal fly ash, having good performance as cement replacement.Portuguese Foundation for Science and Technology (FCT)and the Eco-Construction and Rehabilitation Doctoral Program for supporting the PhD scholarship(reference PD/BD/52661/2014). This work was partly financed by FCT/MCTES through nationalfunds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in StructuralEngineering (ISISE), under reference UIDB/04029/202