Resumo No cenário da Construção Civil, o desempenho dos elementos construtivos constitui uma temática pertinente para a pesquisa científica. Sob esse viés, o objetivo do trabalho consistiu em analisar o comportamento mecânico e térmico de argamassas de revestimento, utilizando diferentes teores - 10%, 20%, 30%, 40% e 50% - de uma fração fina de argila expandida como substituta parcial do agregado convencional, a fim de compará-las a uma argamassa de referência sem argila expandida. Para isso, foram determinadas importantes propriedades mecânicas das argamassas, tanto no estado fresco como no estado endurecido. Além disso, foi determinada a condutividade térmica das argamassas e realizados testes laboratoriais com o auxílio de simuladores de incidência e transferência de calor nas amostras. Os resultados apontam que as argamassas com incorporação de argila expandida não apresentaram impactos negativos nas suas propriedades mecânicas. Em contrapartida, observou-se que o aumento do teor de argila expandida na composição dos traços reduziu a condutividade térmica e aumentou o isolamento térmico das amostras. Desse modo, fica evidente a influência do agregado leve no comportamento térmico das argamassas em estudo, sem comprometer o seu comportamento mecânico.

Abstract In the construction industry context, the performance of constructive elements is a relevant topic for scientific research. Hence, the aim of this study was to analyse the mechanical and thermal behaviour of lining mortars, using different contents - 10%, 20%, 30%, 40% and 50% - of a fine fraction of expanded clay as a partial substitute for the conventional aggregate, in order to compare them with a reference mortar without expanded clay. With that purpose, important mechanical properties of the mortars were identified, both in the fresh state and in the hardened state. In addition, the thermal conductivity of the mortars was determined and laboratory tests were carried out on the samples with the aid of incidence and heat transfer simulators. The results show that the mortars incorporating expanded clay did not present negative impacts on their mechanical properties. On the other hand, the increase in the expanded clay content in the composition of the mixes reduced the thermal conductivity and increased the thermal insulation of the samples. Thus, the influence of light aggregate on the thermal behaviour of the mortars under study is evident, without compromising their mechanical behaviour.

The mechanical metallization is a successful technique at laboratory scale and specially applied to oxide ceramics. Indirect brazing process of zirconia to metals is achieved using active-metal-free filler alloys on previously metallized ceramic. Stabilized zirconia ceramics were mechanically metallized with Ti and wetting conditions evaluated using commercial Ag-Cu and Au-Ni fillers with its respective thermal cycles. Better results were selected for brazing ceramic to metals in a high-vacuum furnace. Reliable vacuum tight ceramic/metal joints were obtained specially using the Ag-28Cu filler for results below 10-8 mbar.ℓ.s-1; samples at the joint cross-section were examined by microstructural analysis techniques and energy dispersive X-ray analysis. Microhardness profiles were made across the joints interface where zirconia undergone a typical darkening effect during brazing. Microstructure at the braze region revealed a dark reaction layer and precipitation zone closely to metallized ceramic surface for zirconia/Ti-6Al4V joints due to chemical interactions between the individual components.