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- Gypsum coatings in ancient buildingsPublication . Malta Da Silveira, Paulo; VEIGA, ROSÁRIO; De Brito, JorgeGypsum plasters from old buildings are a legacy of the building techniques of our ancestors. These coatings, frequently gifted with a high artistic value, are part of the historical building heritage of each country that needs to be well known and preserved. The present paper begins with a general overview of the history of gypsum plasters in Portugal, since the most ancient traces in the Roman period until modern plasters. A description of the main coats that constitute traditional gypsum plasters follows: the lime mortar undercoat, the lime, gypsum and fine sand preparation coat with a thickness of 3–5 mm and the gypsum finishing coat, made of gypsum and air lime slurry. Next, the constitution of the backgrounds is described, namely of the timber framed main walls and of the partition walls typical of the anti-seismic Pombalina construction used in Lisbon after the 1755 earthquake. Finally, the constitutions of the several plaster coats and their production and application process are referred to.
- Aplicabilidade de métodos de estudo da composição de betão auto-compactável (BAC)Publication . Silva, Pedro M.; De Brito, Jorge; Costa, João B.O presente artigo tem como objectivo apresentar os resultados obtidos na campanha experimental para o estudo de verificação da aplicabilidade técnica de dois métodos de cálculo de composição de betão auto-compactável - BAC - propostos por investigadores nacionais em trabalhos anteriores. Com o referido estudo, pretendeu-se, através dos métodos em análise, identificar o método que permite de um modo mais simples, sem necessidade de recorrer a um grande número de amassaduras experimentais, obter as características requeridas aos BAC, tanto no estado fresco como no endurecido. Da análise de resultados efectuada, é possível a comparação entre os métodos estudados e a verificação da sua aplicabilidade, bem como identificar quais os factores que condicionam o processo de cálculo de amassaduras de BAC.
- Environmental life cycle assessment of concrete made with fine recycled concrete aggregatesPublication . Evangelista, Luis; De Brito, JorgeThe majority of worldwide structures use concrete as its main material. This happens because concrete is economically feasible, due to its undemanding production technology and case Of use. However, it is widely recognized that concrete production has a strong environmental impact in the planet. Natural aggregates use is one of the most important problems of concrete production nowadays, since they are obtained from limited, and in some countries scarce, resources. In Portugal, although there are enough stone quarries to cover coarse aggregates needs for several more years, Supplies of fine aggregates are becoming scarcer, especially in the northern part of the country. On the other hand, as concrete structures' life cycle comes to an end, an urgent need emerges to establish technically and economically viable solutions for demolition debris, other than for use as road base and quarry fill. This paper presents a partial life cycle assessment (LCA) of concrete made with fine recycled concrete aggregates performed with EcoConcrete tool. EcoConcrete is a tailor-made, interactive, learning and communications tool promoted by the Joint Project Group (JPG) on the LCA of concrete, to qualify and quantify the overall environment impact of concrete products. It consists of an interactive Excel-spreadsheet in which several environmental inputs (material quantities, distances from origin to production Site, production processes) and outputs (material, energy, emissions to air, water, soil or waste) are collected in a life cycle inventory, and are then processed to determine the environmental impact (assessment) of the analysed concrete, in terms of ozone layer depletion, smog or "greenhouse" effect.
- Mechanical behaviour of concrete made with fine recycled concrete aggregatesPublication . Evangelista, Luís; Brito, Jorge deThis paper concerns the use of fine recycled concrete aggregates to partially or globally replace natural fine aggregates (sand) in the production of structural concrete. To evaluate the viability of this process, an experimental campaign was implemented in order to monitor the mechanical behaviour of such concrete. The results of the following tests are reported: compressive strength, split tensile strength, modulus of elasticity and abrasion resistance. From these results, it is reasonable to assume that the use of fine recycled concrete aggregates does not jeopardize the mechanical properties of concrete, for replacement ratios up to 30%.