Resumo Os revestimentos de paredes mais usados em Portugal, e mesmo ano âmbito europeu e mundial, continuam sendo as argamassas de revestimento, quer sejam à base de cal ou de cimento, quer sejam tradicionais, feitas em obra ou pré-doseadas. De acordo com a normalização disponível, o estudo de desempenho dessas argamassas é realizado sobre provetes produzidos em laboratório, com medidas normalizadas e em condições de cura e de ensaio pré-estabelecidas. No entanto, quando as argamassas são aplicadas sobre os suportes reais o seu comportamento final não será exatamente o mesmo. As dimensões, as condições de aplicação e as condições de cura são distintas. Assim, é consensual dizer que as características finais dos rebocos aplicados em condições reais de exposição serão distintas das obtidas em laboratório. O estudo que se pretende apresentar faz parte de uma investigação mais alargada no âmbito do projeto IF Mortar, em que se pretende analisar a influência das características de diversos suportes nas características de diferentes tipos de argamassa, para se prever, de forma mais rigorosa, qual o comportamento final das argamassas após sua aplicação. Neste artigo são apresentados alguns dos resultados já obtidos em campanhas experimentais, relativos às características físicas de diversas argamassas aplicadas sobre distintos suportes.

Abstract The most commonly used wall coatings in Portugal, and also in the rest of Europe and the world, are still mortars, both lime- and cement- based, be they traditional, on-site or pre-dosed. According to the current standards, performance studies on these mortars are carried out on laboratory-produced specimens, in standard dimensions, and under pre-established curing conditions and tests. However, when mortars are applied to real substrates, their final behaviour will not be the same. The dimensions, application conditions and curing conditions are different. It is, therefore, widely agreed that the final characteristics of mortars applied under real exposure conditions will be different from those obtained in the laboratory. This study is part of a wider investigation in the scope of the IF Mortar project, which aims to analyse the influence of the characteristics of several different supports on the characteristics of different types of mortars, to more accurately predict the final behaviour of mortars after their application. This paper presents some of the results already obtained in experimental campaigns, concerning the physical characteristics of different mortars applied to different supports.

Mortar compressive strength is a standard requirement and should be tested on stand-ardized specimens with a 40 mm square cross section. However, these specimens with only one type of mortar (base-coat layer) do not represent the render traditionally ap-plied to façades since that must consist of at least two layers (base coat and top coat, with different formulations and thicknesses).The in-service compressive strength of the render is therefore currently evaluated on-site by means of indirect methods (e.g. pendulum rebound hammer or ultrasound). Addi-tionally, studies on evaluating the compressive strength in multilayer coating systems, based on the laboratory analysis of the mortar samples collected in situ, are few and far between. This paper intends to discuss the method of assessing in-service compressive strength of applied multi-coat renders systems, by testing cores collected after pull-off tests. Therefore, 422 compressive strength tests were carried out to establish a relation-ship between the compressive strength of single- and multi-coat renders and identify which render layers influence the system’s compressive strength. The experimental cam-paign results have shown the great influence of the top coat on multi-coat renders’ per-formance and the feasibility of studying the in-service compressive strength after a pull-off test; and also allowed identifying relevant parameters to evaluate the strength of samples collected in-situ.