Viability of ceramic residues in lime-based mortars

3rd Historic Mortars Conference, 11-14 September 2013, Glasgow, ScotlandWhen we approach the subject of construction and rehabilitation of buildings we necessarily must think about external wall coatings as they are the elements more exposed to climate actions, mechanical and environmental conditions and, consequently, the first to be deteriorated and to need rehabilitation. In what concerns the replacement of old plasters and renders, air lime mortars are normally the ones that are more compatible with the existing elements, but that have some limitations due to its slow setting time. As an alternative we may use natural hydraulic lime mortars. We know that brick dust and grains have been widely used in mortars in the past, improving its characteristics, and that actually there are many kinds of ceramic residues that are byproducts of industry and are normally carried into landfills. Within this context and associating the improvement of mortars characteristics to the necessity of sustainable construction practices, some mortars, formulated based on air lime or natural hydraulic lime, with the addition of ceramic residues, have been recently studied. The aim of this paper is to present the experimental work that has been developed concerning the behaviour of two types of these lime mortars with ceramic residues. Characteristics, particularly in terms of flexural and compressive resistances, capillary water absorption and water vapour permeability will be discussed. Comparison will be made between the characteristics of the mortars made with the two limes, and of mortars made with those limes with partial substitutions of siliceous sand by different types of ceramic residues. It will be possible to draw same conclusions about the interest and viability of recycling the ceramic residues as aggregates, its contribution as pozzolan and filler, and also if natural hydraulic lime-based mortars can be a good alternative to air lime-based mortar for ancient masonry

Air lime and natural hydraulic lime mortars with ceramic residues for rehabilitation of old buildings

41st IAHS World Comgress - Sustainability and Innovation for the FutureRepair of old facades renders requires particular attention because raw materials currently available hardly ever correspond to the requirements for this purpose. Usually, in those cases, air lime mortars are more suitable; however, they imply long curing periods. Alternative solutions such as natural hydraulic lime mortars might reveal appropriate. In the past, it was also common the use of ceramic fragments and dust in mortars for plastering and rendering, which improved their behaviour. Considering the high amounts of residues currently produced by ceramic industries, the development of mortars with this residue might be a technically viable solution, and also respond to economic and environmental issues. In the present paper it is described a part of a large experimental campaign involving the characterization of air lime and natural hydraulic lime mortars with ceramic residues from bricks, roof tiles and pottery. A comparison is made between the results obtained for the two groups of mortars, considering physical and mechanical properties. Volumetric proportions of 1:2 (air lime mortars) and 1:4 (natural hydraulic lime mortars) were used and ceramic residues replaced 20%, 30% and 40% of the aggregate (common sand). The obtained results show that the incorporation of ceramics might provide significant changes in mortars porous structures and, consequently, in their mechanical and physical behaviour. Globally, when considering the studied properties, the analysed mortars may be regarded as suitable for rehabilitation purposes

Characterization of mortars with ceramic residues

XIII DBMC – 12th International Conference on Durability of Building Materials and Components,2-5 September 2014, Universidade de São Paulo, São Paulo, BrazilMortar coatings are usually the first elements to deteriorate, once they are the most exposed construction elements. Taking into account their protective function, it is easily understood the importance of the development of a correct conservation / rehabilitation intervention. Old mortars were essentially air lime based and their rehabilitation must be executed with compatible mortars. That way they not only recover the protective function, but also contribute to maintain the integrity of the whole wall-render element and the aesthetic image of the building. As it is known, many old lime-based mortars had ceramic residues in their composition, which are very abundant residues, particularly in Portugal. Thus, in an attempt to combine the interest of reusing waste ceramic, reducing the amounts that are typically landfilled, with the technical benefits that they can bring to rehabilitation mortars, an experimental research has been developed, at the University of Coimbra, in collaboration with the NOVA University of Lisbon, on the behavior of lime mortars with incorporation of ceramic residues. In this paper a comparison between air lime mortars with ceramic residues with volumetric proportions of 1:3 and 1:2 (binder:aggregate) will be presented, showing the advantages of the reintroduction of the ceramic residues into the productive chain. Studied mortars revealed a quite satisfying behavior as the inclusion of ceramic residues may improve the characteristics of common air lime mortars.EXPL/ECM-COM/0928/2012 - Incorporation of ceramic residues in repair mortars (Fundação para a Ciência e Tecnologia) / EMSURE - Energy and Mobility for SUstainable REgions (CENTRO-07-0224-FEDER-002004

Lime mortars with heat treated clays and ceramic waste: A review

The formulation and use of lime mortars with ceramic particles has, in the past, been a very common technique. Knowledge of such used techniques and materials is fundamental for the successful rehabilitation and conservation of the built heritage. The durability that these mortars have shown encourages the study of the involved mechanisms, so that they may be adapted to the current reality. The considerable amount of waste from old ceramics factories which is sent for disposal might present an opportunity for the production of reliable improved lime mortars. In this paper a number of studies that characterize old building mortars containing ceramic fragments are reviewed. The most important research undertaken on laboratory prepared mortars with several heat treated clays types is presented, specifically with incorporated ceramic waste. Some studies on the pozzolanicity of heat treated clays are examined and the heating temperatures that seem most likely to achieve pozzolanicity are presented. It was verified that some heating temperatures currently used by ceramic industries might correspond to the temperatures that will achieve pozzolanicity.EXPL/ECM-COM/0928/2012 - Incorporation of ceramic residues in repair mortars (Fundação para a Ciência e Tecnologia) / EMSURE - Energy and Mobility for SUstainable REgions (CENTRO-07-0224-FEDER-002004

Long-term characterization of air lime mortars with ceramic waste

Due to their exposure to environmental conditions, outer coatings composed by render and painting system are usually the first construction elements to deteriorate and require intervention. A correct conservation and rehabilitation of these materials is fundamental once they provide protection to other façade materials. It is known that old mortar renders were essentially air lime based mortars. To maintain the integrity of the whole wall-render elements, the image of the building and to avoid accelerated degradation, conservation and rehabilitation must be implemented with compatible mortars. As that, lime based mortars would be preferable. It was also common, in ancient renders, the incorporation of ceramic residues, which is, nowadays, an abundant material, especially in Central Region of Portugal. The reuse of these materials has great relevance once their landfilling causes serious environmental issues. In an attempt to combine the environmental and technical advantages of the use of ceramic waste in mortars’ production for rehabilitation purposes, a research has been developed at the University of Coimbra, in cooperation with Nova University of Lisbon, on the long term behaviour of air lime mortars with ceramic residues. In this paper the most significant up to one year results of an experimental campaign with air lime mortars with 1:3 and 1:2 volumetric proportions and ceramic residues are presented.FCT – Fundação para a Ciência e Tecnologia (PTDC/ECMCOM/3080/2012 – Development and optimization of a higroadjustable system for drying out buildings after a flood); Energy and Mobility for Sustainable Regions – EMSURE Project (CENTRO-07-0224-FEDER-002004)

The influence of brick residues in the behaviour of lime mortars

XXXVI IAHS World Congress on Housing - National Housing Programs-New Visions, November 03–07, 2008, Kolkata, IndiaMortars have a great repercussion on the durability of a masonry construction due to its protective role. The compatibility among the masonry materials (the masonry units, the mortar of the joints, the plasters and the renders) incites the adequate behaviour of the wall and consequentially an increase in durability. Very often we came across with rehabilitation errors due to the use of incompatible mortars whether with the pre-existing mortar or with the others wall materials, which can origin great pathologies. Repair mortars should be compatible with existent materials. Old mortars were normally air lime based and sometimes had in their composition some other products like brick dust which confer specific properties. Small grains of brick residue can take the role of a particular aggregate and brick dust of a pozzolan, reacting with the calcium hydroxide of the air lime and improving the mortars behaviour. Simultaneously its application has the great advantage of reuse an industrial by-product. With the increasing environmental concerns it is important to find appropriate solutions to the industry residues. In this way we can contribute for a better use of the material resources and to the decrease of deposition of residues in landfills by studying its performance as part of a repair mortar. The propose of this paper is to present the results obtained in an experimental work developed at the University of Coimbra which main goal was to analyze the influence of brick residues coming from an industrial plant in the behaviour of lime mortars to be applied as repair mortars, assuring the compatibility and protection of old masonries

Lime mortars with ceramic wastes: characterization of components and their influence on the mechanical behaviour

Considering the fundamental importance of preserving the built heritage and of ensuring the good performance achieved by incorporating ceramic particles in lime mortars in ancient times, it is important to study solutions that use materials the available today, in order to produce mortars intended to repair and replace the old ones. Solutions incorporating industrial ceramic waste might be profitable for several reasons, namely for economic, environmental and technical aspects. In this paper, seven ceramic waste products collected from ceramics factories are characterized. Their mineralogy, dimensional features and pozzolanicity were determined. Three of these products, with different particle size fractions (obtained directly from milling, dust only and fragment fractions only), were selected, incorporated into air lime mortars, and their mechanical strength was determined. In the present work, evidence of mechanical efficiency, when common sand or air lime were partially replaced by ceramic wastes, was made clear, drawing attention to the sustainability of this type of mortars, hence, encouraging further research.EXPL/ECM-COM/0928/2012 - Incorporation of ceramic residues in repair mortars (Fundação para a Ciência e Tecnologia) / EMSURE - Energy and Mobility for SUstainable REgions (CENTRO-07-0224-FEDER-002004

Lime mortars with brick dust and grounded particles for ancient masonry: development and evaluation

HMC08 - 1st Historical Mortars Conference: Characterization, Diagnosis, Conservation, Repair and Compatibilit, LNEC, Lisbon, 24-26 September 2008Lime mortars with brick dust and grounded particles have been largely used in many regions of the world as plasters, renders and in masonry joints and repointing. In Portugal this type of pozzolanic mortars has been introduced at least since the Roman period, particularly when hydraulic characteristics were needed. Brick dust, a source of silica and also of alumina, react with the calcium hydroxide of the lime, resulting on silicates and aluminates of calcium hydrates. The brick particles (grounded to appropriate dimensions) will act as a specific aggregate. The lime mortars with brick material are supposed to achieve hydraulic characteristics and increment their mechanical resistances and durability, compared to pure lime mortars. Also the mortar behavior in face of water (liquid and vapor) will be changed. Lime mortars with brick material also present compatibility with ancient supports, what does not happened with cement mortars. Within this context and associating the improvement of mortars characteristics to the necessity of sustainable construction practices, some mortars formulated with lime and the addition of industrial by-products have been recently studied by several researchers. To present pozzolanic reactivity, the brick material should be in an amorphous form, obtained from a low thermal industrial process. It also should be finely grounded, so that there is a big surface of pozzolanic particles to react. The aim of this work is to present the evaluation of the influence of brick dust and of brick particles in lime mortars. Characteristics, particularly in terms of flexural and compressive resistances, capillary water absorption and water vapor permeability will be discussed. The repair mortars requirements of compatibility with the ancient masonries and their protection will be analyzed. Considering the increase of some characteristics revealed by some mortars with brick dust and with brick particles, when compared with a pure lime mortar, it is possible to evaluate the benefits of the addition of this type of pozzolan and aggregates in lime mortars, and the viability of this industrial by-product reutilization

Argamassas de Reabilitação com Resíduos de Cerâmica

Tese de Doutoramento em Engenharia Civil, na especialidade de Construções apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraQuando abordada a questão da reabilitação de edifícios antigos, um dos fatores essenciais a considerar é a preservação dos rebocos exteriores, na medida em que estes são os elementos mais expostos às agressões ambientais e, consequentemente, os primeiros a manifestar sinais de degradação. O seu papel fundamental na proteção dos restantes elementos das alvenarias deverá ser tido em conta e, como tal, a escolha de materiais e soluções construtivas adequadas carece de especial rigor. As argamassas de cal aérea são, em geral, as que apresentam maior compatibilidade com os elementos existentes em edifícios antigos, tendo, no entanto, períodos de cura extensos que por vezes condicionam a sua aplicação. No passado, era também frequente o recurso a fragmentos de tijolo e outros materiais cerâmicos submetidos a tratamento térmico que, quando incorporados em argamassas de cal, melhoravam o seu desempenho e conferiam-lhes características de hidraulicidade. Neste sentido, a utilização de cal hidráulica natural poderá também revelar-se uma alternativa adequada. O estudo aprofundado deste tipo de argamassas e a sua adaptação ao atual contexto da construção reveste-se de extrema importância, uma vez que a facilidade com que é possível, ainda hoje, encontrar este tipo de soluções em edifícios antigos é bastante representativa da sua durabilidade. A quantidade de resíduos produzidos atualmente pelas indústrias cerâmicas poderá ser uma oportunidade para, não só reaproveitar materiais que são considerados desperdício, e correntemente depositados em aterro, mas também para produzir argamassas tecnicamente viáveis e com desempenho melhorado. A presente tese tem como principal objetivo a procura de soluções adequadas para a reabilitação de rebocos antigos, a partir de argamassas com resíduos cerâmicos, permitindo, não só, o desenvolvimento de soluções adequadas do ponto de vista técnico, mas também do ponto de vista ambiental. Neste sentido, foi realizada a recolha e caracterização de resíduos cerâmicos de várias indústrias nacionais, para posterior incorporação em argamassas de cal aérea e cal hidráulica natural. Após caracterização detalhada dos resíduos, quer no que respeita ao processo produtivo, quer em termos de propriedades dos materiais, foi desenvolvida uma extensa campanha experimental no sentido de caracterizar as argamassas formuladas em termos físicos e mecânicos, no estado fresco e no estado endurecido. Foram realizados ensaios em condições laboratoriais e em condições de exposição ambiental exterior, em diversas idades de cura. A caracterização das argamassas no estado endurecido foi desenvolvida em três fases distintas: numa primeira fase foi realizada a caracterização de um conjunto alargado de formulações, em termos físicos e mecânicos, em condições laboratoriais; a segunda fase consistiu na caracterização complementar das argamassas que apresentaram desempenhos mais adequados para o propósito pretendido, selecionadas com base nos resultados de caracterização da primeira fase; numa terceira fase foi selecionado um conjunto restrito de argamassas das fases anteriores, que foi caracterizado em condições ambientais exteriores, com recurso à aplicação de painéis de reboco num edifício antigo. O trabalho desenvolvido permitiu aferir a influência, no desempenho de argamassas de cal aérea e de cal hidráulica natural, de fatores como as características dos resíduos e as dosagens utilizadas, tendo sido analisada detalhadamente a viabilidade da utilização deste tipo de composições na reabilitação de edifícios antigos. No geral, a incorporação de resíduos de cerâmica teve um impacto positivo nas propriedades estudadas das argamassas de cal

Caracterização física de argamassas de cal aérea com resíduos de cerâmica

A reabilitação e manutenção das fachadas antigas requer especial atenção sobretudo porque os materiais atualmente utilizados não correspondem, muitas vezes, aos requisitos exigidos para o efeito. No caso concreto das argamassas de reboco é possível observar com frequência erros associados à escolha dos produtos, que induzem uma degradação acelerada dos revestimentos e particularmente dos respetivos suportes, comprometendo a durabilidade dos sistemas. Era frequente, no passado, o recurso a argamassas de cal aérea e, em alguns casos, com incorporação de resíduos de cerâmica, que lhes conferiam um desempenho melhorado. Nestas circunstâncias, e tendo em conta o volume de resíduos produzidos pelas indústrias cerâmicas, geralmente depositados em aterro, o desenvolvimento de soluções de argamassas de revestimento com incorporação destes resíduos poderá apresentar-se como uma solução viável, não só do ponto de vista técnico, mas também ambiental. Este estudo apresenta a caracterização de argamassas de cal aérea ao traço 1:2 e 1:3 com resíduos de cerâmica, destinadas à reabilitação de rebocos de edifícios, no que respeita ao comportamento face à presença de água. Verifica-se que a introdução de resíduos conduziu ao aumento da resistência à difusão do vapor de água, da absorção de água por capilaridade e da porosidade aberta e à redução da capacidade de secagem. No entanto as diferenças face às argamassas de referência só de cal foram geralmente pouco significativas, pelo que particularmente as argamassas ao traço 1:2 com resíduos indiciam ser adequadas para aplicação em edifícios antigos