In these days of economic crisis subsiding, in the civil engineering the attention is pointed especially to the systems, which effectively reduce energy and decrease costs associated with using of residential or industrial premises. Especially the heat-insulating systems are mentioned, because of their characteristics and construction which will be applied economical solutions. It is possible to use the materials based on aerated concrete which excel within construction materials due to its heat-insulating properties. The use of this material for clearly heat-insulations seems to be fully-fledged alternative to standard heat-insulating systems also due to combination of nature character and sufficient strength. This work deals with possibility of preparation non-bearing, heat-insulating material based on autoclaved aerated concrete with volume weight under 200 kg/m3.

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The use of cellular concrete in buildings has been increasing recently due to its advantages (low density, better thermal comfort, among others). Some norms already regulate its application for walls of one floor buildings, and normative projects, still under development, which will regulate its application with structural purposes for walls of multi-level buildings. However, there still is not a specific dosage method that relates the formulation with the compression strength for cellular concrete manufacture, moreover, there are many variables (additive dosage, generation process of air bubbles, diameter, density and volume of bubbles, use of coarse aggregates, etc.), which influence the production process that needs a better understanding. Therefore, this study had as objective to evaluate the obtaining and properties of different types of cellular concrete, with the application intensio for structural purposes in construction walls. Thus, three types of cellular concrete procedures were developed adopting dosage procedures and different materials and compositions. The first with foam generated by generators (CESP), using foaming agent chemical additive (AESP), without coarse aggregate. The second with chemical additives incorporating the air bubbles through the mechanical action of the mixer (CBAM), also without coarse aggregate. And the third with coarse aggregates (CBAMG), and incorporating additives of air bubbles. The properties were evaluated in the fresh state (density, consistency and incorporating air content) and in the hardened state (compression strength). Based on results, the production of CESP was found to be made difficult by the use of foam-generator, damaging their manufacture, despite in agreement with the normative requirements for construction applications. CBAM presented a lower variability in the manufacturing process providing a better performance. Finally, CBAMG presented an improvement in workability compared to the CBAM concrete. The highest compression strength of cellular concrete CESP, CBAM and CBAMG, at 28 days, were 6.5 MPa, 19.5 MPa and 23.5 MPa, respectively, this can be applied in walls with structural purposes. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Atualmente o uso de concreto celular em edificações vem crescendo devido as suas vantagens (baixa densidade, melhor conforto ambiental e outras). Algumas normas já regularizam sua aplicação em paredes para edificações térreas, e projetos de normas, ainda em elaboração, que irão regularizar sua aplicação com fins estruturais em paredes de edificações de vários pavimentos. Entretanto, para a obtenção de concretos celulares ainda não existem métodos de dosagens que relacionem sua formulação com a resistência à compressão, além disso, há muitas variáveis (dosagem de aditivo, processo de geração das bolhas de ar, diâmetro, densidade e volume das bolhas, uso de agregados graúdos, etc.) que influenciam no processo de produção necessitando de um melhor entendimento. Neste sentido, o presente estudo teve como objetivo avaliar a obtenção e as propriedades de diferentes tipos de concretos celulares, com o intuito de aplicação para fins estruturais em paredes de edificações. Para isso, três tipos de concretos celulares foram desenvolvidos adotando diferentes procedimentos de dosagens, materiais e composições. O primeiro com formação de espumas geradas através de geradores (CESP), utilizando aditivo químico espumígeno (AESP), sem agregado graúdo. O segundo com aditivo químico incorporador de bolhas de ar através da ação mecânica do misturador (CBAM), também sem agregado graúdo. E o terceiro com agregados graúdos (CBAMG) e aditivos incorporadores de bolhas de ar. Foram avaliadas as propriedades no estado fresco (densidade, consistência e teor de ar incorporado) e no estado endurecido (resistência à compressão). Com base na análise dos resultados verificou-se que a produção do CESP foi dificultada pelo uso dos geradores de espuma, prejudicando sua obtenção, apesar de atender os requisitos normativos para aplicações em edificações. Já o CBAM apresentou menor variabilidade no processo de obtenção proporcionando um melhor desempenho. Quanto ao CBAMG este apresentou uma melhora na trabalhabilidade comparado aos concretos de referência CBAM. As maiores resistências à compressão dos concretos celulares CESP, CBAM e CBAMG, aos 28 dias, foram, 6,5 MPa, 19,5 MPa e 23,5 MPa, respectivamente, podendo estes serem aplicados em paredes com fins estruturais.

The main requirement of the user with regard to the constructive system is to have the guarantee of that this is really safe, that is, that it really comes to take care of to the requirements of structural security. The evaluation of structural performance, is one of the forms to determine if the system is really safe; the ideal would be that all and any constructive system, before being launched in the market, it was submitted to the performance evaluations leading in consideration the requirements of the users: security, habitability and support; only in such a way, if it would have the guarantee of that possible problems presented during the evaluation, they would not be repassed the users, being corrected in its initial stage. Therefore, in this work, the performance evaluation happened of inverse form, where the constructive system was evaluated by means of assays of field after the residences being concluded. The carried through assays of field had looked for to evaluate the structural performance of the residences of soil-cement and cellular concrete through the assays of verification of resistance the impacts, occupation loads, verification of the behavior of the leaf (door) submitted the abnormal maneuvers and evaluation through the criteria of the state has limited of use. In such a way, the behavior of these residences through the comparison could be evaluated enters the gotten results in the assays of field and the criteria established for the Projects of Norms of the ABNT nos 02.136.01.001, 02.136.01.002 e 02.136.01.004 (ABNT, 2004) 2004 that it evaluates the performance of residences, well as, to verify the constructive systems that had not taken care of to the established criteria, indicating its imperfections, guaranteeing with this not the occurrence of these in future constructions. / A principal exigência do usuário com relação ao sistema construtivo é ter a garantia de que este é realmente seguro, ou seja, que venha realmente a atender aos requisitos de segurança estrutural. A avaliação de desempenho estrutural, é uma das formas para determinar se o sistema é realmente seguro; o ideal seria que todo e qualquer sistema construtivo, antes de ser lançado no mercado, fosse submetido às avaliações de desempenho levando em consideração as exigências dos usuários: segurança, habitabilidade e sustentabilidade; somente desta forma, se teria a garantia de que possíveis problemas apresentados durante a avaliação, não seriam repassados aos usuários, sendo corrigidos em sua etapa inicial. Neste trabalho, a avaliação de desempenho aconteceu de forma inversa, onde o sistema construtivo foi avaliado por meio de ensaios de campo depois das unidades habitacionais estarem concluídas. Os ensaios de campo realizados procuraram avaliar o desempenho estrutural das unidades habitacionais de solo-cimento e concreto celular através da verificação da resistência a impactos, cargas de ocupação, verificação do comportamento da folha (porta) submetida a manobras anormais e avaliação através dos critérios do estado limite de utilização. Desta forma, pôde-se avaliar o comportamento destas residências através da comparação entre os resultados obtidos nos ensaios de campo, e os critérios estabelecidos pelos Projetos de Normas nos 02.136.01.001, 02.136.01.002 e 02.136.01.004 (ABNT, 2004) que apresentam os métodos para avaliar o desempenho de edifícios habitacionais, bem como verifica os sistemas construtivos que não atenderam aos critérios estabelecidos, indicando suas falhas, garantindo com isso a não ocorrência destas em construções futuras. / Mestre em Engenharia Civil

Low-strength cellular concrete consists of a cement slurry that is aerated prior to placement. It remains a largely untested material with properties somewhere between those of soil, geofoam, and typical controlled low-strength material (CLSM). The benefits of using this material include its low density, ease of placement, and ability to self-compact. Although the basic laboratory properties of this material have been investigated, little information exists about the performance of this material in the field, much less the passive resistance behavior of this material in the field.In order to evaluate the use of cellular concrete as a backfill material behind bridge abutments, two large-scale tests were conducted. These tests sought to better understand the passive resistance, the movement required to reach this resistance, the failure mechanism, and skew effects for a cellular concrete backfill. The tests used a pile cap with a backwall face 5.5 ft (1.68 m) tall and 11 ft (3.35 m) wide. The backfill area had walls on either side running parallel to the sides of the pile cap to allow the material to fail in a 2D fashion. The cellular concrete backfill for the 30° skew test had an average wet density of 29.6 pcf (474 kg/m3) and a compressive strength of 57.6 psi (397 kPa). The backfill for the 0° skew test had an average wet density of 28.6 pcf (458 kg/m3) and a compressive strength of 50.9 psi (351 kPa). The pile cap was displaced into the backfill area until failure occurred. A total of two tests were conducted, one with a 30° skew wedge attached to the pile cap and one with no skew wedge attached.It was observed that the cellular concrete backfill mainly compressed under loading with no visible failure at the surface. The passive-force curves showed the material reaching an initial peak resistance after movement equal to 1.7-2.6% of the backwall height and then remaining near this strength or increasing in strength with any further deflection. No skew effects were observed; any difference between the two tests is most likely due to the difference in concrete placement and testing.