Evolução do processo de carbonatação em argamassas de cal aérea

• Autor(a) principal: Oliveira, Mateus António Nogueira
• Data de Publicação: 2021
• Outros Autores: Azenha, Miguel, Lourenço, Paulo B., Souza, José Victor Brasil de
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/1822/88476
• topic: Aerial lime; Mortar; Carbonation; Thermogravimetric analysis; Phenolphthalein; Cal aérea; Argamassa; Carbonatação; Análise termogravimétrica; Fenolftaleína; Science & Technology

Aerial lime has been used as binder for centuries and different types of mortars were fabricated using the material during the history around the world. Different properties of the aerial lime mortars are associated with the carbonation process (e.g. chemical, mechanical response), in this sense a set of experiments are proposed to study the progress of the mentioned phenomenon. The research was initialized with the definition of the mortar composition: 1:1.3:3 (lime:water:aggregate). This definition followed an iterative process considering the consistence of the mixture and the bibliographical references. The influence of the size of specimens on the carbonation evolution was evaluated adopting cylinders with five different diameters. They were tested using phenolphthalein spray at three different ages (10, 21 and 90 days). Discs with reduced thickness (similar to 2 mm) were stored in three different environments (standard, high humidity and high CO2 concentration), samples were collected at different aged (1, 4, 7, 14, 21, 28 days) and tested by thermogravimetric analysis (TGA). The results indicate a significant effect of the size of specimens on the carbonation depth and the environment on the evolution of carbonation, with depth variation of similar to 120%, specimens with reduced dimensions when evaluated with phenolphthalein spray presented a faster reaction as well as the small specimens store in the environment with high CO2. In both cases the elevated humidity on the initial phase tends to reduce the velocity of the reaction.