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The ingress of carbon dioxide CO2 into concrete is an issue that, unfortunately, does not have sufficient precedents at the national level for the execution of the Residual Service Life analysis of concrete structures. As a precursor element of steel corrosion, it is necessary to count on information on the behavior that concrete could have in Chile, according to the levels of aggressiveness expected for specific project locations. It was only in 2016 that the NCh170 Concrete Standard included this type of Exposure with Grade C1 as Mild Aggressiveness. This work presents a review of background information collected from various third-party and own works, along with measurements of Carbonation Rates in 20-year-old concretes made in the city of Santiago, relating them to Air Permeability measured in a non-destructive way, which allowed generating a proposal for the Classification of the Degree of Exposure to Carbonation.

Los autores han estado involucrados en la creación y primeros ensayos y desarrollos del llamado "Método Torrent" para medir la permeabilidad al aire del hormigón. Transcurridos más de 15 años de ese trabajo fundacional, el artículo presenta una revisión de la evolución y estado de situación del método, incluido como Norma Oficial Suiza en 2003. Se presentan ejemplos de su aplicación en laboratorio y en obras (puentes, túneles, etc.), con datos de valores medidos, provenientes de distintos países del mundo. Se presentan correlaciones entre el coeficiente de permeabilidad al aire kT y otros indicadores de durabilidad, tales como la migración de cloruros (ASTM C1202) y la penetración de agua a presión (EN 12390-8) o por capilaridad. Finalmente se discuten sus perspectivas de uso futuro, como herramienta de control de calidad de estructuras nuevas, con las importantes implicancias que ello acarreará, así como de diagnóstico de estructuras existentes.The authors have been involved in the creation, preliminary tests and development of the "Torrent Method", which is intended to test air permeability in concrete. It's been more than 15 years since such foundational research and, now, this paper presents a review of the evolution and current situation of the Method, included in the Switzerland standards in 2003. Application examples conducted in laboratory and civil works (bridges, tunnels, and so on) are introduced, including data from different countries worldwide. Correlations between the air permeability coefficient kT and other durability indicators, such as chloride migration (ASTM C1202), penetration of water under pressure (EN 12390-8) or capillary action are presented. Finally the future prospective uses are discussed, as quality control tool for new structures, considering relevant implications they would lead to, as well as the diagnosis on existing structures.

Social interactions among conspecifics are a fundamental and adaptively significant component of the biology of numerous species. Such interactions give rise to group living as well as many of the complex forms of cooperation and conflict that occur within animal groups. Although previous conceptual models have focused on the ecological causes and fitness consequences of variation in social interactions, recent developments in endocrinology, neuroscience, and molecular genetics offer exciting opportunities to develop more integrated research programs that will facilitate new insights into the physiological causes and consequences of social variation. Here, we propose an integrative framework of social behavior that emphasizes relationships between ultimate-level function and proximate-level mechanism, thereby providing a foundation for exploring the full diversity of factors that underlie variation in social interactions, and ultimately sociality. In addition to identifying new model systems for the study of human psychopathologies, this framework provides a mechanistic basis for predicting how social behavior will change in response to environmental variation. We argue that the study of non-model organisms is essential for implementing this integrative model of social behavior because such species can be studied simultaneously in the lab and field, thereby allowing integration of rigorously controlled experimental manipulations with detailed observations of the ecological contexts in which interactions among conspecifics occur.