Polymer-modified mortars are highly popular for setting exterior tile systems and low-porosity ceramic tiles because they possess greater flexibility and higher bond strengths than conventional mortars which increases cladding serviceability. However, the long-term performance of this application is not completely understood and many pathologies has been reported. The negative influence of water saturation on polymer modified mortar is well documented and this paper investigates the influence that progressive water intake on bond strength by applying pull out tests on several different mortars. Four of those mortars were especially prepared with well known raw materials and concentrations, and three others were ready-made commercial products designed for setting ceramic tile on building façades. The tests were performed during twenty-five day drying period in laboratory conditions after specimens saturation for ten days of immersion in water. The results revealed that: (i) the ready-made commercial and the prepared mortars have similar behavior; (ii) their bond strengths are highly influenced by small increases in moisture content; (iii) moisture content higher than 10% is enough to reduce mortar bond strength by one-half; (iv)during the drying process bond strength increases continuously until reaching values similar to the initial ones.
The service life of buildings can be associated with the durability of enveloping the elements, e.g., the flat roofs that are constantly exposed to environmental agents. Waterproof membranes, produced with bituminous or polymeric materials, usually protect these elements. This paper presents an experimental study of waterproofing systems subjected to environmental agents of degradation. Four types of membranes were tested: bituminous, polyurethane, acrylic and acrylic with polyester mesh. All membranes were applied to concrete substrates and exposed to cycles of 48 hours in 70°C oven and 24 hours in immersion vats with 23°C water. The specimens were subjected to 0, 4, or 8 cycles and submitted to pull-off tests. The results demonstrated that the waterproof system behavior change when subjected to cycles of the temperature gradient. The tests show that the different thermal deformation between the membranes and the concrete substrate results in loss of adhesion.
Na construção civil, a depender do tipo de recurso avaliado (mão de obra, material ou equipamento), a literatura designa indicadores específicos para obtenção da produtividade. Pouco se discute no meio técnico-científico a respeito da interpretação e utilização desses indicadores associados com seu nível de abrangência (diário, cumulativo ou cíclico), em especial associados a um tratamento estatístico. Nesse contexto, o presente estudo tem como objetivo promover tais discussões, de forma a auxiliar a avaliação da produtividade em obra e proporcionar aos gestores uma alternativa matemática eficiente de acompanhamento, baseada na análise de dados e estatística, que pode ser aplicada mesmo com recursos limitados.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.