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- Desempenho de argamassas reforçadas com fibras acrílicasPublication . Oliveira, Luiz Pereira de; Alves, Paula C. P.; Dias, Sérgio M. M.O artigo apresenta os resultados de um estudo experimental desenvolvido com uma argamassa mista, na qual se adiciona fibras acrílicas com o objectivo de avaliar o comportamento das mesmas em matriz cimentícia. A avaliação do desempenho das fibras acrílicas foi realizada com ensaios de flexão e compressão, comparativamente com fibras de vidro e polipropileno. Ensaios de retracção em túnel de vento foram realizados para avaliar a capacidade das fibras em absorver esforços e evitar fissuração. Conclui-se que as fibras acrílicas têm comportamento mecânico semelhantes as fibras de referência e quanto a retracção as fibras acrílicas apresentam bom desempenho.
- The influence of self-compacting steel fibre reinforced concrete infill on the flexure strength and ductility of masonry wallsPublication . Oliveira, Luiz Pereira de; Bernardo, LuísThis paper presents an experimental study on the influence of longitudinal reinforcement ratio and steel fibre volume in self-compacting concrete infill on the strength and ductility of reinforced masonry walls subjected to flexure. Flexure tests were performed as four-point bending tests on twelve walls. The analysis of the concrete infill contribution to the walls capacity is made considering recent recommendations for steel fibre reinforced concrete design. A ductility index was defined and applied to study the ductility behaviour of the masonry walls. The analysed variables are the longitudinal reinforcement ratio and the steel fibre volume in the concrete infill.
- Propriedades do betão auto-compactável com incorporação de agregados finos recicladosPublication . Pinto, Hugo; Oliveira, Luiz Pereira de; Nepomuceno, MiguelEste estudo teve como objectivo analisar o impacto nas propriedades do betão auto-compactável (BAC) resultante da incorporação de agregados finos reciclados em substituição parcial dos agregados finos naturais. O programa experimental realizado envolveu, numa primeira fase, a produção e ensaio de 11 misturas binárias com percentagens sucessivamente crescentes de agregados finos reciclados. Posteriormente, foram ainda produzidas e ensaiadas 6 misturas ternárias para o mesmo efeito. Nas misturas binárias, a percentagem de substituição do agregado fino natural por agregado fino reciclado variou desde os 0% (mistura de referência) até aos 50% em incrementos de 5%, enquanto nas misturas ternárias a percentagem de substituição do agregado fino natural por agregado fino reciclado variou desde os 0% (mistura de referência) até aos 50% em incrementos de 10%. O estudo permitiu concluir que as argamassas com incorporação de agregados finos reciclados constituem um material viável e com potencialidades de utilização na indústria da construção, desde que sejam ponderados os ajustes necessários ao seu desempenho.
- Effect of particle size distribution and calcium aluminate cement on the rheological behaviour of all-alumina refractory castablesPublication . Silva, Abílio P.; Segadães, A M; Pinto, Deesy G.; Oliveira, Luiz A.; Devezas, TessalenoPrevious works based on statistical design of experiments (DoE) defined a model all-alumina self-flow refractory castable (SFRC) with optimized particle size distribution for simultaneous high flowability index (FI) and superior post-sintering performance. This work compares the SFRC rheological behaviour and setting time with those of alternative all-alumina castables with different Andreasen aggregate particle size distribution modulus, and of the equivalent castables containing calcium aluminate cement. The model castable showed Bingham behaviour with low yield stress, viscosity and thixotropy, guaranteeing easier casting and less wear in the casting and/or projection equipment. However, as the coarse particle fraction increases, the castable flow tends to be non-linear and changes from Bingham to Herschel–Bulkley. The cement containing castables quickly loose flowability despite the applied shear. This work confirmed previous conclusions based on FI measurements and demonstrates the adequacy of the use of FI values in the calculation of FI response surface by DoE.
- Use of refurbished shipping containers for the construction of housing buildings: details for the structural projectPublication . Bernardo, Luís; Oliveira, Luiz Pereira de; Nepomuceno, Miguel; Andrade, Jorge Miguel AlmeidaConstruction using refurbished shipping containers is a recent building system, with already many successful examples around the world. This system presents a huge potential in the field of sustainable construction provided by the recycling of used containers. This paper aims to contribute to a better knowledge of this construction system in what concerns to the structural project. The general constitution of two maritime shipping containers is presented as well as some aspects of their structural behavior. For this purpose, numerical analyses were performed using a finite elements analysis program. Normative aspects for the structural project are also presented. This paper also presents the analysis of a case study with the use of refurbished shipping containers to build a single-family house. The evaluation of the strength of the refurbished shipping containers to building actions is carried out. It is shown that such evaluation is not easy because some mechanical parameters of noncommercial steel section of the elements that compose the shipping containers are unknown. Nevertheless, this study shows the feasibility of this building system.