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This study reports the use of lime mud (LM) in cement-based-mortars. Lime mud is a waste generated in the production of cellulose by the kraft mill process. It is mainly composed of CaCO3, a small amount of magnesium carbonate and other trace minerals. Mortars were prepared by adding different amounts of LM (10, 20 and 30% by weight of cement) in dry weight. The mortar compositions were evaluated through rheology and flow table measurements, assuring that all the samples exhibited adequate conditions for testing in both equipments. The hardened state properties were also evaluated through mechanical strengths at 7, 28 and 90 days of curing. Following a waste management solution perspective, this work intend to provide a general evaluation of LM application in cement based mortars, looking at both fresh and hardened properties in order to guarantee that the final application requirements are not hindered., Este estudio revela el uso de lodo de carbonato (LM) en morteros de cemento. El LM es un residuo compuesto principalmente por CaCO3 generado en la producción de pasta de papel por el método Kraft. Los morteros se prepararon a partir de la adición de diferentes niveles de LM (10, 20 y 30% en peso de cemento) en peso seco. Las composiciones de los morteros fueron caracterizadas através de mediciones de reología de mesa y de flujo, asegurando que las muestras exhibían condiciones adecuadas para su caracterización en ambos equipamientos. Las propiedades en estado endurecido también se evaluaron através de resistencias mecánicas a los 7, 28 y 90 días de cura. Con objeto de gestión de residuos, este trabajo tiene la intención de proporcionar una visión general de la aplicación de LM en los morteros, haciendo hincapié en las propiedades con el fin de garantizar que los requisitos para su aplicación final no se vean obstaculizados.

Este artigo pretende apenas dar um contributo, assinalando alguns exemplos em que se tem vindo a trabalhar e que refletem o uso de tecnologias avançadas na formulação e funcionalidade de materiais de construção tradicionais. Um exemplo claro é o uso de aditivos que induzem novas funções e que muitos deles pertencem ao grupo denominado como nanomateriais. A sua adição coloca quase sempre problemas de incorporação e que requerem um trabalho de ajuste das formulações e comportamentos no estado fresco ou endurecido. Este trabalho de investigação é muitas vezes essencial para a otimização das funções que se pretendem que os materiais de construção venham a demonstrar. Neste grupo de investigação, resultante da cooperação entre centros de I&D e empresas em projetos de colaboração diversos ao longo dos últimos anos, tem-se vindo a focar na introdução de novas funções em materiais de construção tradicionais, para que ganhem um papel ativo em domínios como o do conforto térmico ou da qualidade ambiental, dois pilares essenciais para uma construção mais sustentável.

Masonry walls constitute the interface between the building’s interior and the outdoor environment. Masonry walls are traditionally composed of fired-clay bricks (solid or perforated) or blocks (concrete or earth-based), but in the past (and even in the present) they were often associated as needing an extra special thermal and acoustical insulation layer. However, over more recent years investigations on thermal and acoustical features has led to the development of new improved bricks and blocks that no longer need these insulation layers. Traditional masonry units (fired-clay bricks, concrete or earth-based blocks) that don’t offer improved performance in terms of thermal and acoustical insulation are a symbol of a low-technology past, that are far removed from the demands of sustainable construction. This book provides an up-to-date state-of-the-art review on the eco-efficiency of masonry units, particular emphasis is placed on the design, properties, performance, durability and LCA of these materials. Since masonry units are also an excellent way to reuse bulk industrial waste the book will be important in the context of the Revised Waste Framework Directive 2008/98/EC which states that the minimum reuse and recycling targets for construction and demolition waste (CDW) should be at least 70% by 2020. On the 9th of March 2011 the European Union approved the Regulation (EU) 305/2011, known as the Construction Products Regulation (CPR) and it will be enforced after the 1st of July 2013. The future commercialization of construction materials in Europe makes their environmental assessment mandatory meaning that more information related to the environmental performance of building materials is much needed., (undefined)

Putting forward an innovative approach to solving current technological problems faced by human society, this book encompasses a holistic way of perceiving the potential of natural systems. Nature has developed several materials and processes which both maintain an optimal performance and are also totally biodegradable, properties which can be used in civil engineering. Delivering the latest research findings to building industry professionals and other practitioners, as well as containing information useful to the public, ‘Biotechnologies and Biomimetics for Civil Engineering’ serves as an important tool to tackle the challenges of a more sustainable construction industry and the future of buildings.

Carbonation is a major cause of concrete structures deterioration leading to expensive maintenance and conservation operations. The eco-efficient construction agenda favours the increase of the use of supplementary cementing materials (SCMs) to reduce Portland cement’s consumption and also the use of recycled aggregates concrete (RAC) in order to reduce the consumption of primary aggregates and to avoid landfill disposal of concrete waste. There is a wide range of literature published on the field of concrete carbonation related to the use of SCMs and/or RCA. However, the different conditions used by different authors limit comparison and in some cases contradictory findings are noticed. Besides, since most investigations are based on the use of the phenolphthalein indicator, which provides a poor estimate of the real concrete carbonation depth, there is a high probability that past researches could have underestimate the corrosion potential associated to concrete carbonation. This paper reviews current knowledge on concrete carbonation addressing carbonation depth’s measurement, the use of SCMs and or RAC.

A incorporação de resíduos industriais em matrizes cimentícias, com o objetivo de inertização, é uma alternativa de reutilização que tem sido bastante estudada nos últimos anos. No presente trabalho, estudou-se a lama vermelha, resíduo sólido gerado no processo de beneficiamento da bauxita e que, devido a seu elevado pH, é considerado "perigoso". Apesar do uso deste resíduo ter sido reportada em trabalhos anteriores, algumas patologias podem estar associadas à sua utilização, devido à elevada concentração de íons alcalinos (principalmente o sódio), favorecendo as reações álcalis-sílica (RAS) e às dificuldades de moldagem (reologia) devido à elevada finura deste resíduo. Apesar destes prováveis problemas provenientes do uso indiscriminado da lama vermelha como adição às argamassas e concretos, ainda são poucas as pesquisas que os contemplam, sendo este o foco do presente trabalho. Foram verificadas as propriedades reológicas das argamassas, utilizando um reômetro e a avaliação da RAS, de acordo com as normas ASTM C 1260-07 e NBR 11582. Os resultados obtidos foram bastante satisfatórios quanto ao comportamento das argamassas frente à RAS, apesar da elevada concentração de álcalis na lama vermelha, com grande influência reológica. The incorporation of industrial wastes in cementitious matrices, with the goal of inertization, is an alternative of reuse that has been extensively studied in recent years. In this paper, the red mud, the main waste generated in aluminum and alumina production by the Bayer process from bauxite ore and considered "hazardous" due to the high pH, was studied. Despite the use of this waste have been reported in previous studies, some pathologies may be associated with its use, due to high concentration of alkali ions (mainly sodium), favoring the alkali-silica reactions (ASR) and the difficulties of molding (rheology) because of high fineness of this waste. Despite these potential problems arising from the indiscriminate use of red mud as an addition to mortars and concrete, there are few studies that contemplate this problem, and is the focus of the present work. The rheological properties of mortars were studied using a rheometer, and the evaluation of ASR was evaluated, according to ASTM C 1260-07 and NBR 11582 standards. The results were very satisfactory as to the mortars behavior concerning the ASR, despite the high alkali concentration in red mud, with great rheological influence.

The alkali–silica reaction (ASR) in concrete occurs by reaction of certain silica phases in the aggregates with alkalis and hydroxide ions in the pore solution of the hydrating cement to produce a hydrous alkali-silicate gel. This gel can swell by incorporating large amounts of water, causing severe and irreversible expansion and cracking of the concrete. The level of expansion and disruption in concrete containing reactive aggregate depends on the alkali content of the concrete and the reactivity of the aggregate. The levels of alkali that trigger the expansion depend, however, on the reactivity of the aggregates. Alkalis from Portland cement (OPC) are one of the major sources of these ions in concrete. The use of industrial by-products such as fly ash and slag has been found to be an effective preventive measure against ASR in concrete. This article presents the performance of biomass fly ash - an industrial by-product - in the mitigation/inhibition of ASR in concrete. Laboratory expansion tests were conducted to evaluate the performance of biomass fly ash, in replacement of OPC by 20% and 30% (w/w) in the experiments (ASTM C1260/ASTM C1567). The results revealed that biomass fly ash has a good potential in the expansion inhibition due to ASR. The authors wish to acknowledge Fundação para a Ciência e Tecnologia (FCT) for the financial support under project EXREACT PTDC/CTM/65243/2006) and PhD grant SFRH/BD/32500/2006. 1 4 7p DM/NMM 2011 3 a 8 de Julho

Peer-reviewed journal article, Applied Rheology

O objectivo principal deste trabalho prende-se com o estudo da possibilidade de reutilizar «óxido secundário» resultante do tratamento de reciclagem de escória salina, como matéria-prima a adicionar as argamassas de cimento Portland.. O comportamento da escória à lixiviação aquosa , a análise química da solução, do soluto e das várias fracções resultantes da separação granulométrica dos óxidos lixiviados por espectrometria de fluorescência de rais X (FRX), são alguns dos resultados apresentados. O comportamento toxicológico da escória, antes e após lixiviação, complementa a sua caracterização. O estudo do efeito da adição do óxido lixiviado de grão fino (

The incorporation of several industrial wastes in ceramic matrixes had been attempted as an effective low expense technique for the fixation of metallic species in usable products or simply to reduce the residue volume for further disposal. However, the dominant mechanism of the inertization process and the relevant influent parameters are still unknown, mostly due to the complexity of the systems. This work reports the effect of several processing parameters such as the mixing time, the calcination temperature and duration, the relative amount of sludge, and the physical aspect of the sample (powdered or pressed pellets) on the fixing level of relevant species (SiO2, SO4 2−, Zn, Ni, Ca, Cu, Cr) by leaching in different media (aqueous, acetate, and citrate). Statistical tools were used to define the relevance of each experimental variable on the inertization process of the used galvanic sludge. The relative amount of sludge in the mixture, the calcination temperature and the agglomeration state of the sample were found to be the most influent parameters of the inertization process. The incipient reaction between sludge and ceramic matrix components points out for the dominance of a macro- encapsulation mechanism.

Estudou-se a incorporação de escórias salinas de alumínio e lamas galvânicas de anodização de alumínio, como matéria prima para a fabricação de materiais refractários.

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La conductivida d mixta (iónica y electrónica) es un requerimiento importante para un material como buen electrodo; con el objeto de asegurar alta actividad electrocatalítica y buen rendimiento cuando se usa en aplicaciones de estado sólido. En aire, la mayoría de las perovskitas ensayadas muestran alta conductividad electónica (por mecanismos de saltos) y además deficiencia de oxígeno, que es la responsable de la conducción oxígeno-ión. En particular, CaMn03 puede acomodar alta concentración de vacantes de oxigeno, formando canales que producen alta mobilidad de oxigeno. Sin embargo, las composiciones deficientes en oxigeno obtenidas mediante condiciones reductoras no son estables en atmósferas oxidantes, siendo la recuperación del oxigeno muy rápida a alta temperatura. En este trabajo se recogen los intentos preliminares de estabilizar composiciones CaMn03-x (O < x < 0.5) a alta temperatura, incluyendo la substitución parcial de Sr por Ca (hasta 0.5). DRX, ATD, TG y medidas de conductividad eléctrica fueron utilizadas para caracterizar los procesos redox.