Cement blocks with EVA waste for extensive modular green roof: contribution of the components for thermal insulation

Abstract Green roofs can contribute in many ways to the quality of the environment, being known for reducing the heat transfer to the interior of the buildings. Amongst the available techniques for the execution of this type of covering, the use of light cement blocks which are compatible with the system of extensive modular green roofs is proposed. For the light cement blocks, produced with EVA aggregates (waste from the footwear industry), an additional contribution in the capacity of thermal insulation of the proposed green roof is expected. In the present article, the demonstration of such contribution is intended through measurements carried out in prototypes in hot and humid climates. After characterizing the capacity of thermal insulation of the proposed green roof, with different types of conventional covering as a reference, an additional contribution of the component used in this green roof was identified by making comparisons with measurements collected from another green roof, executed with cement blocks without the presence of the EVA aggregates. In the experiments, external and internal surface temperatures were measured in each of the prototypes' coverings, as well as the air temperatures in the internal and external environments. From the analysis of the data for a typical summer day, it was possible to prove that the proposed green roof presented the lowest temperature ranges, considering the internal air and surface temperatures. The presence of the EVA aggregates in the proposed blocks contributed to the decrease of the internal temperatures. Resumo As coberturas vegetadas podem contribuir de várias maneiras na qualidade do meio ambiente, sendo destacada a redução na transferência de calor para os ambientes internos das edificações. Dentre as técnicas disponíveis para execução desse tipo de cobertura propõe-se o uso de blocos cimentícios leves compatíveis com o sistema de telhado verde extensivo modular. Para os blocos cimentícios leves, produzidos com agregados de EVA (resíduos da indústria de calçados), espera-se uma contribuição adicional na capacidade de isolamento térmico do telhado verde proposto. No presente artigo, pretende-se demonstrar tal contribuição, através de medições realizadas em protótipos na condição de clima quente e úmido. Após caracterizar a capacidade de isolamento térmico do telhado verde proposto, tendo como referência diferentes tipos de coberturas convencionais, foi identificada a contribuição adicional do comp