Comportamento térmico de argamassas de revestimento externo com substituição parcial do agregado miúdo por materiais reciclados

Abstract

The growth in energy consumption in buildings, the scarcity of natural resources and the increase in waste production leveraged the need to develop sustainable solutions in the civil construction sector. The incorporation of waste in the external coating mortar indicates environmental benefits, reducing the consumption of natural resources, and allows the improvement of the thermal properties of a building, in order to contribute to the thermal performance of the facades and to increase energy efficiency. Thus, the objective of this study was to evaluate the thermal behavior of external coating mortars with partial replacement of fine aggregate by recycled materials – expanded polyethylene, leather and ethylene vinyl acetate (EVA) – towards the thermal performance. Waste contents of 25, 50 and 75% were investigated. The evaluation of thermal properties was carried out through the differential scanning calorimetry (DSC) and the thermal conductivity (ABNT NBR 15220-4: 2005 calculation method). The results showed a reduction in the density of the mortars with wastes, which provided a lower thermal conductivity. With the results of the DSC test, it can be seen that the enthalpy value was higher for samples with 50% of EVA and 75% of expanded polyethylene compared to the reference mortar, resulting in greater thermal insulation and less thermal conductivity and specific heat. Considering also other properties of the external coating mortar, such as compressive strength and flexural strength, absorption by capillarity – related to impermeability and certain pathologies – and water/cement ratio, the results point to an increase or similarity of performance in relation to the conventional mortar, with the incorporation of expanded polyethylene wastes among all contents and EVA with 25% of incorporation.