ABSTRACT Sustainable development has become part of Government policy across the world. In the construction industry it has been introduced through the promotion of “sustainable construction” or “green construction”. International trends show a gradual move away from wasteful construction industry practices that include high resource consumption, material wastage, inefficiencies in construction processes and a high percentage of waste that find its way to waste disposal sites and illegal dumps. This research report seeks to promote sustainable construction and waste minimisation as preferred models for achieving a balance in the economic, social and environmental impacts of development. It reviews South Africa’s construction and demolition site practice from the perspective of construction and demolition waste management, assessing waste management practice and the resultant waste disposal. To gauge South Africa’s performance it benchmarks South African practice against those of the United States, United Kingdom, Germany and the Netherlands. This approach highlights gaps in South Africa’s current practice and also provides some valuable lessons that can be used to ensure compliance with sustainable construction principles. Finally the research report proposes a framework for developing a self-sustaining secondary construction materials market in South Africa, which can prove to be a valuable tool for ensuring the absorption of sustainable construction in the construction industry.

Os resíduos de construção e demolição (RCD) representam cerca de 50% de todo o resíduo sólido gerado, sendo que cerca de 90% deste é de origem mineral e pode ser reciclado através de processos de beneficiamento mineral. Para se atingir a reciclagem massiva torna-se imperativo o desenvolvimento de novos mercados e melhorias de usina capazes de tornar o resíduo uma matéria prima de qualidade adequada. Dessa forma a caracterização tecnológica é imprescindível para obtenção de informações fundamentais sobre o processo de beneficiamento e as especificações para os produtos. O programa experimental foi desenvolvido em três amostras de RCD britados de duas usinas de reciclagem do Estado de São Paulo, Itaquera cinza (IT-C), Itaquera vermelho (IT-V), Vinhedo vermelho (VI-V). As atividades desenvolvidas foram: amostragem, cominuição, determinação das composições químicas e mineralógicas por faixa granulométrica, determinação de propriedades físicas relevantes para reciclagem de RCD como agregados para uso em concreto, determinação das curvas de separabilidade por densidade e análise de sua composição química e mineralógica e estudos microscópicos para avaliação do teor de aglomerantes por faixa densitária. Os resultados de análises químicas mostram que as composições químicas das três amostras são semelhantes; os teores variam com a granulometria, com marcantes diferenças na fração mais fina. A composição mineralógica predominante é de silicatos, provenientes de agregados e rochas naturais, cerâmicas e aglomerantes, com menores teores de alumina e óxido de cálcio; a perda ao fogo está diretamente relacionada ao teor de aglomerantes, uma vez que representa a água combinada e o gás carbônico presente. A separação do RCD em classes de densidade permitiu identificar que os produtos obtidos apresentam composições diferentes e pode ser empregada para se obter agregados de melhor qualidade e, portanto, para aplicações mais nobres, uma vez que se verifica que cerca de 80% em massa dos resíduos possuem densidades superiores a 2,2 g/cm3 com qualidades físicas adequadas para uso em concreto estrutural. Adicionalmente, a massa específica aparente e absorção de água estão diretamente relacionadas com os intervalos de densidade. O teor de aglomerantes aumenta significativamente para os produtos de menor densidade, sendo que as partículas cerâmicas estão isentas de pasta de cimento endurecida e cal. / Construction and demolition waste (CDW) represents around 50% of the total solid waste and are essentially constituted by mineral fraction (>90%); therefore it?s possible to recycle it through mineral processing techniques. The development of different uses and the improvement of the typical technologies applied to CDW recycling are essential to achieve a satisfactory level of recycling. Applied mineralogy tools are fundamental to characterize the studied raw material and support the mineral processing in order to obtain products according to its specifications. This research was carried out in three crushed samples from two different plants close to Sao Paulo; they were named according to its classification: grey Itaquera (IT-C), red Itaquera (IT-V) and red Vinhedo (VI-V). The method involved basically sampling, crushing, characterization of the relevant physical properties for a concrete recycled aggregate approach, evaluation of the specific gravity separability curves and chemical and mineralogical analyses for each grain size fraction and gravity classes, and so microscope analyses to verify the binder contents. The results show that the chemical composition of the three samples is very similar, the grades change according to the grain size fractions, specially for the finest fraction. The mineral composition is also quite akin, it is mostly represented by silicates (mainly aggregates and natural rocks), ceramics and binder; minor amounts of Al2O3 and CaO were also detected. The loss of ignition is directly related to the binder and clay minerals (basically OH and CO2). Specific gravity classes are very different regarding their chemical, mineralogical and physical properties, despite their similarity among the samples. Thus the specific gravity separation is more effective to classify the recycled CD debris than its color and could be applied to obtain high quality recycled aggregates, while a significant amount (80%) is recovered above 2.2 g/cm3 and may be used as high strength concrete aggregates. In addition, the physical properties, like specific gravity and water absorption are strictly related to the specific gravity classes.

Os resíduos de construção e demolição (RCD) são gerados em quantidades expressivas nas cidades de grande e médio portes no Brasil e são comumente descartados de forma irregular. Para os milhares de quilômetros de vias urbanas não pavimentadas, o agregado reciclado de resíduo sólido da construção civil é uma alternativa aos materiais convencionais de pavimentação. Esta dissertação analisa o comportamento mecânico do agregado reciclado para emprego em camadas de base e sub-base. A pesquisa consiste em ensaios laboratoriais, acompanhados de um estudo de caso - o pavimento do novo campus da Universidade de São Paulo (USP Leste). Um trecho de 1.020 metros de extensão foi utilizado no estudo, de um total de aproximadamente dois quilômetros de vias pavimentadas no campus. O pavimento avaliado possui agregado reciclado em sua estrutura; quatro seções-tipo diferentes foram construídas, variando os materiais, as espessuras, a compactação e o subleito. Propriedades físicas e mecânicas do agregado reciclado foram determinadas em laboratório por meio dos seguintes testes: composição, porcentagem de materiais indesejáveis, massa específica, absorção de água, graduação, forma dos grãos, compactação, influência da compactação, índice de suporte Califórnia, módulo de resiliência e deformação permanente. Os ensaios de campo compreenderam: controle de materiais e de execução, resistência à penetração pelo Dynamic Cone Penetrometer e levantamento deflectométrico com o Falling Weight Deflectometer. Baseado na análise das bacias de deflexão das seções-tipo construídas, o trecho estudado é dividido em quatro comportamentos distintos à deformação. Os resultados mostraram que o comportamento mecânico do agregado reciclado apresenta uma forte dependência da eficiência da compactação. Quando submetido a uma compactação adequada, o material reciclado comporta-se tal qual uma brita graduada simples. / Construction and demolition waste (CDW) is generated in significant amounts in medium and large size cities in Brazil and are usually disposed of illegally. For the thousands of kilometers of unpaved urban roads, the recycled aggregate of CDW is an alternative to conventional paving materials. This dissertation analyses the mechanical behavior of the recycled aggregate for use in base and subbase layers. This research consisted of a series of laboratory tests, followed by a case study - the pavement of the new campus of the University of Sao Paulo (USP Leste). A test track of 1,020 meters of extension was used for the study, from a total of approximately two kilometers of paved roads in the campus. The pavement studied contains recycled aggregate in its structure; four different road sections were constructed, varying the materials, thickness, compaction and subgrade. Physical and mechanical properties of the recycled aggregate were characterized through the following laboratory tests: composition, percentage of impurities, bulk density, water absorption, gradation, grain form, compaction, compaction influence, California Bearing Ratio, resilient modulus and permanent deformation. The field tests covered: materials and construction control, bearing capacity using the Dynamic Cone Penetrometer and deflection measurement using a Falling Weight Deflectometer. Based on the analysis of the deflection basins of the built road sections, the test track is divided according to four different deformation behaviors. The results show that the mechanical behavior of the recycled aggregate presents a strong dependence on the compaction effort. When submitted to proper compaction, the recycled material behaves as a crushed-stone.

O processo de demolição tradicional tem experimentado várias mudanças, a emergência das preocupações ambientais leva hoje a procurar formas mais sustentáveis, como a aplicação de uma demolição que promova a desmontagem e a remoção seletiva dos materiais, através do planejamento antecipado e da aplicação contínua das regras de segurança, executando uma correta gestão do fluxo de resíduos por meio da sua reutilização. Este trabalho tem como principal objetivo desenvolver um conjunto de diretrizes que permitem aprimorar o planejamento das atividades de demolição de pequenas edificações térreas, por meio de uma análise normativa nacional e internacional sobre o processo de demolição, promovendo práticas mais sustentáveis a serem adotadas por pequenas empresas demolidoras. Neste sentido a pesquisa empírica foi realizada pela aplicação de três estudos de caso, desenvolvendo um diagnóstico do funcionamento das atividades das empresas que praticam a demolição seletiva em pequenas edificações, com a elaboração de entrevistas, acompanhamento das demolições e da revenda dos materiais. Assim sendo, foi possível verificar a existência de mercados para os materiais e componentes reaproveitados das obras de demolição, os materiais mais procurados são os tijolos maciços, as telhas de cerâmica e a madeira, como por exemplo a Peroba Rosa, foi possível também observar a escassa de segurança e a falta do uso dos equipamentos de proteção. Esta pesquisa contribuiu com o desenvolvimento de um conjunto de ações que maximizem a coordenação da execução das tarefas em obra, de modo a melhorar a segurança e o aproveitamento de materiais, diminuindo o custo da demolição através da revenda dos materiais obtidos, e minimizando a produção de resíduos sólidos. / The traditional demolition process has experienced several changes, and the emergence of environmental concerns leads today, to seek for more sustainable ways, such as applying a demolition that promotes the dismantling and the selective removal of materials, through early planning and the continuous application of safety rules, making it much more diverse materials obtained and performing a proper management of the waste stream through reuse. This work main objective has to develop a set of guidelines that allow to improve the planning of the demolition activities of small buildings, through a national and international normative analysis of the demolition process, promoting more sustainable practices to be adopted by small demolition companies. In this way, the empirical research was carried out by the application of three case studies, developing a diagnosis of the activities that companies practice, by using the selective demolition in small buildings, with the elaboration of interviews, monitoring the demolitions and the resale of the materials. As result, it was possible to verify the existence of markets for reused materials and components of the demolition works. The most wanted materials are solid bricks, ceramic tiles, and wood, such as Peroba Rosa. This research contributed to the development of a set of actions that maximize the coordination of the execution of the tasks at work, in order to improve the safety and the use of materials, reducing the cost of demolition through the resale of the obtained materials, and minimizing the production of solid waste.

abstract: The built environment is responsible for a significant portion of global waste generation. Construction and demolition (C&D) waste requires significant landfill areas and costs billions of dollars. New business models that reduce this waste may prove to be financially beneficial and generally more sustainable. One such model is referred to as the “Circular Economy” (CE), which promotes the efficient use of materials to minimize waste generation and raw material consumption. CE is achieved by maximizing the life of materials and components and by reclaiming the typically wasted value at the end of their life. This thesis identifies the potential opportunities for using CE in the built environment. It first calculates the magnitude of C&D waste and its main streams, highlights the top C&D materials based on weight and value using data from various regions, identifies the top C&D materials’ current recycling and reuse rates, and finally estimates a potential financial benefit of $3.7 billion from redirecting C&D waste using the CE concept in the United States. / Dissertation/Thesis / Masters Thesis Civil, Environmental and Sustainable Engineering 2019

<p>This thesis studies the Danish and Norwegian recycling systems for construction and demolition (C&D) waste. The architectural, Engineering and Construction (AEC) industry is a major contributor to societies waste production; accounting for approximately 40% of the waste production. It is therefore important to manage the C&D waste effectively to move society towards sustainability.</p><p>This study applies the Industrial Ecology paradigm. This involved multidisciplinary approach, spanning the fields of Industrial Ecology, Systems Engineering and Organizational and Social Studies.</p><p>The scope of this thesis is threefold. The first scope is to get a better understanding of the processes that are taking place within the socio-technical sphere of a recycling system. Second, what is the nature of the C&D waste and what are the environmental impacts from the various waste fractions. Third, how can this information be used to improve recycling systems for C&D waste.</p><p>The study show that the suggestions in the National Action Plan and the corresponding policies are eco-effective, but that the environmental impact is very transport dependent. The study also shows that there is a great need to focus on future waste composition in the design of recycling systems for C&D waste. However, such waste projections are difficult to perform due to poor data availability.</p><p>There is a need for making more qualified decisions on environmental issues, with regard to long term management of such recycling systems. Long term models combined with environmental and economic information can make a powerful tool for such analysis.</p>

This thesis studies the Danish and Norwegian recycling systems for construction and demolition (C&amp;D) waste. The architectural, Engineering and Construction (AEC) industry is a major contributor to societies waste production; accounting for approximately 40% of the waste production. It is therefore important to manage the C&amp;D waste effectively to move society towards sustainability. This study applies the Industrial Ecology paradigm. This involved multidisciplinary approach, spanning the fields of Industrial Ecology, Systems Engineering and Organizational and Social Studies. The scope of this thesis is threefold. The first scope is to get a better understanding of the processes that are taking place within the socio-technical sphere of a recycling system. Second, what is the nature of the C&amp;D waste and what are the environmental impacts from the various waste fractions. Third, how can this information be used to improve recycling systems for C&amp;D waste. The study show that the suggestions in the National Action Plan and the corresponding policies are eco-effective, but that the environmental impact is very transport dependent. The study also shows that there is a great need to focus on future waste composition in the design of recycling systems for C&amp;D waste. However, such waste projections are difficult to perform due to poor data availability. There is a need for making more qualified decisions on environmental issues, with regard to long term management of such recycling systems. Long term models combined with environmental and economic information can make a powerful tool for such analysis.

Syftet med arbetet var att identifiera ytor inom Södertörn där det skulle vara möjligt att etablera materialterminaler för hantering av byggbranschens jord- och bergmaterial. Förhoppningen var att detta kunde bidra till ett planeringsunderlag för en samordnad materialförvaltning inom regionen. Behovet och nyttan av fler materialterminaler har börjat uppmärksammas, men inga studier kring vilka platser som lämpar sig för ändamålet har tidigare genomförts utifrån svenska förhållanden.   För att ta reda på vilka kriterier som definierade en bra materialterminalyta genomfördes en intervjustudie där tio aktörer med anknytning till materialhanteringsbranschen intervjuades. Kriterierna översattes till geografisk information och implementerades i GIS-programmet ArcMAP där det konstruerades en kartbild vilken visualiserade de ytor som var lämpliga respektive olämpliga att använda för ändamålet. Därefter genomfördes ett exempel vilket visade hur kartunderlaget kunde användas för att göra ett första urval av potentiella platser för en terminal inom angivet avstånd från utvalda byggprojektområden. För att ytterligare bidra till planeringsunderlaget identifierades regionens nuvarande materialterminaler, även de redovisades i en geografisk bild konstruerad i ArcMAP. I stort var de intervjuade aktörerna överens om vilka kriterier en materialterminalyta bör uppfylla. De främsta tycktes vara följande; att terminalen har ett bra logistiskt läge som ger korta transporter, att den kan avskärmas från boende och andra som vistas i området, att den har liten konkurrens från andra intressen och ligger utanför miljökänsliga områden samt har en (tillräckligt) stor yta. GIS-analysen och dess resulterande kartbild visade att det fanns stora tillgängliga ytor som uppfyllde kriterierna och som potentiellt skulle kunna användas till nya materialterminaler inom Södertörn. Detta strider mot den vedertagna uppfattningen om att platsbrist är en av de största anledningarna till att terminaler inte har kunnat etableras. Alla kriterier fanns dock inte representerade i analysen, vissa visade sig nämligen vara svåra att översätta till geografisk information. Dessutom fanns det inte alltid tydliga gränser mellan när en markyta kunde användas och inte, i flera fall tycktes det bero på platsspecifika egenskaper. Antaganden och subjektiva bedömningar låg därmed delvis till grund för hur kriterierna representerades i kartbilden. Dessa antaganden och bedömningar baserades dock på intervjuer med kunniga och insatta aktörer samt relevant litteratur, resultaten bedömdes därmed som rimliga och kartbilden möjlig att använda för att få en uppfattning om potentiella materialterminalplatser. GIS-analysen med resulterande kartunderlag skulle kunna användas för att göra ett första urval av potentiella terminalplatser som sedan analyseras vidare innan slutgiltigt val. Rapporten kan användas till att få en bredare kunskap om materialterminaler, vilka kriterier och krav de bör uppfylla och hur berörda aktörer tänker kring dessa. / The purpose of this thesis was to identify areas within Stockholm’s southernmost municipalities (Södertörn) where it was possible to establish terminals where soil and rock material used within the construction industry could be stored and sorted. This should contribute to the planning of a coordinated material management in the region. The need for and usefulness of these hubs have begun to be recognized, but no studies about suitable sites based on Swedish conditions has previously been carried out. In order to find the criteria that define a favourable area for such a site ten stakeholders with connection to the material management were interviewed. The criteria were then translated into geographic information and implemented in the GIS software ArcMap, where a map visualizing the areas that were suitable respectively unsuitable for the purpose was constructed. Thereafter an example which showed how the map could be used to make an initial selection of potential sites within a specified distance from selected construction sites was carried out. In order to further contribute to a coordinated material management the region's current sites for soil and rock handling were identified, also presented in a geographical image constructed in ArcMap. Overall the interviewed stakeholders agreed about which criteria a soil and rock handling site should meet. The most important ones seemed to be the following; a good logistical location which minimizes transportation distances, possibility to shield it from residents and others staying in the area, little competition from other interests, a location outside environmentally sensitive areas, and finally, an area that is (sufficiently) large. The result showed that there existed large accessible areas that could potentially be used for the establishment of new handling sites within Södertörn, which contradict the opinion that the lack of space is one of the major reasons to that these kind of establishments can’t be established. All criteria were not represented in the map though, this since some were not possible to translate into geographic information. Moreover, clear boundaries between when an area could be used and not were sometimes lacking, it seemed to depend on site-specific characteristics. How the criteria were represented in the map was therefore partly based on assumptions and subjective judgments. Assumptions and estimates were however based on interviews with knowledgeable stakeholders and relevant literature and were therefore considered to be reasonable. The map was considered to be able to give an indication of where were soil and rock handling sites potentially could be established. The map could be used to make an initial selection of potential sites, which then can be further analysed before a final choice. The report can be used to gain a broader understanding of these kind of establishments, the criteria and requirements they must meet, and what involved stakeholders think about these.

A questão ambiental é um tema muito discutido e pesquisado atualmente. Isto advém da constatação que os recursos naturais não são ilimitados e que o meio ambiente não tem a capacidade de absorver a quantidade atual de resíduos sem que haja um desequilíbrio ambiental. Neste contexto insere-se a indústria da construção civil, que apresenta importantes impactos ambientais em todas as etapas do seu processo produtivo, sendo um destes a geração de resíduos de construção e demolição (RCD) em centros urbanos, que resulta em efeitos deteriorantes do ambiente local onde estes são dispostos e, em virtude do seu desperdício, aumenta a extração de materiais minerais. Um dos meios de reduzir-se a quantidade de RCD disposto no meio ambiente e a extração de materiais minerais é a reciclagem do RCD e sua utilização na própria indústria que o gerou.Neste sentido, os blocos de concreto para pavimentação surgem como uma alternativa de pesquisa, já que estes têm ganhado espaço como solução para a pavimentação de áreas urbanas. Isto se deve ao aumento dos esforços de empresas e entidades representativas do setor em incentivar sua utilização e às vantagens técnicas inerentes ao sistema, como o fácil assentamento, a rápida liberação para o tráfego, a redução de iluminação pública e a permissão de acesso à rede subterrânea apenas com a retirada dos blocos, que podem ser recolocados após intervenção. Neste sentido, o presente trabalho estudou a utilização do RCD, proveniente de Porto Alegre – RS, como agregado miúdo reciclado em substituição ao agregado miúdo natural em blocos de concreto para pavimentação. Foi utilizado o intervalo de teores entre 0 % e 100%, com o objetivo de investigar-se um espectro grande de possibilidades de utilização do agregado miúdo reciclado de RCD, sendo que os ensaios escolhidos (resistência à compressão, resistência à abrasão e absorção de água) tiveram o intuito de dar subsídios ao entendimento do comportamento dos blocos produzidos perante as substituições. Após a realização dos ensaios, verificou-se que para o teor de 25% de substituição o material reciclado é passível de utilização, sendo que para os outros teores os resultados foram insatisfatórios. / Environmental issues are in the public eye and are the focus of extensive research nowadays as it becomes clear that natural resources are limited and that the large amounts of waste generated today will necessarily result in environmental imbalances. A considerable share of this waste is generated by the construction industry, whose activities hold a potential environmental impact throughout the stages of their production processes. Construction and demolition (C&D) waste generated in cities often produces detrimental effects in the sites where debris is dumped, a problem which is compounded by the fact that this waste could be used as a substitute for fresh materials that have to be extracted from mines, another activity with considerable environmental impact. A possible way to reduce the amount of C&D waste dumped in the environment and also the need for fresh mineral resources is the recycling of C&D waste by the same industry that generated it. Research on the use of concrete block paving provides an interesting alternative as this material has become more widely used in pavements of urban areas as a result of the efforts of construction companies and associations, which now endeavor to promote the use of concrete blocks. These have intrinsic technical advantages, such as their fast placement, the fast release of paved areas to traffic, the reduced need for street lighting and the ease of access to underground networks because blocks can be quickly opened up and reinstated. The present study investigated the use of C&D waste produced in Porto Alegre, RS, Brazil as a recycled substitute for conventional fine aggregate in concrete block paving. C&D waste was used as fine aggregate in concentrations ranging from 0% to 100% to provide a detailed picture of the possibilities of using recycled C&D waste as fine aggregate. The tests selected (compressive strength, abrasion resistance, water absorption) were used to provide information on the behavior of the blocks produced using different concentrations of C&D waste. These tests show that a concentration of 25% of recycled material as a substitution can be used with satisfactory results while all other concentrations yielded unsatisfactory results.

This work analysed some mechanical and durability properties of the concrete produced with fine and coarse aggregates obtained from the recycling of construction and demolition wastes (CDW) in order to evaluate the possibility to use this composite in structures. A special attention was given to the degree of porosity/strength of the coarse recycled aggregate assuming its specific gravity as one of the parameters of the study. Construction and demolition wastes were gathered from illegal deposition areas inside Maceió and were comminuted in laboratory; the grains obtained were divided into fine aggregate and coarse aggregate. One part of the coarse aggregate was mixed in with recycled concrete aggregate in order to produce a new aggregate which was less porous/stronger than the first one the amount of aggregates to be mixed were determined through a rule of mixture for the specific gravity. Concretes were produced in laboratory combining three water-cement ratio with each coarse recycled aggregate and fine recycled aggregate or river sand; reference concretes were produced with natural aggregates too. The properties of the recycled concretes were also investigated by means of a factorial design. In general, the use of coarse recycled aggregate combined with fine coarse aggregate was not good, but the less porous the coarse recycled aggregate (or the higher the specific gravity), the better the concrete properties were. Some recycled aggregate concretes reached strength values bigger than the reference concrete. Results showed that recycled concretes can be used in structures, but with some restrictions. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O trabalho analisou algumas das propriedades mecânicas e de durabilidade do concreto produzido com agregados miúdos e graúdos de RCD reciclado no intuito de avaliar a possibilidade de uso do compósito em estruturas. Uma atenção especial foi dada ao nível de porosidade/resistência do agregado graúdo reciclado. Para isso, tomouse como um dos parâmetros do estudo a sua massa específica. Os resíduos de construção e demolição foram coletados em áreas de deposição ilegal dentro da cidade de Maceió e foram cominuídos em laboratório, sendo o material granular obtido separado em duas frações: agregado miúdo e agregado graúdo. Uma parte do agregado graúdo foi misturada com agregado graúdo de concreto reciclado de forma a produzir um novo agregado reciclado menos poroso/mais resistente as quantidades dos dois agregados a serem misturadas foram determinadas com o auxílio de uma regra de mistura para a massa específica. Traços foram produzidos em laboratório com três níveis de relação a/c combinando-se cada agregado graúdo reciclado com o agregado miúdo reciclado ou com uma areia natural. Ao mesmo tempo, concretos de referência foram produzidos com agregados naturais. As propriedades dos concretos reciclados foram analisadas também por meio de um experimento fatorial. Em termos gerais, o uso combinado de agregado graúdo reciclado com agregado miúdo reciclado não foi vantajoso, mas as propriedades dos concretos foram tanto melhores quanto menor foi a porosidade (ou, maior a massa específica) dos agregados graúdos reciclados. Alguns concretos reciclados chegaram a apresentar resistências mecânicas maiores que as de seus respectivos concretos de referência. Os resultados encontrados permitem afirmar que concretos reciclados podem ser usados em estruturas, mas com restrições.