Pore characterization of heterogeneous building materials: Pyroclastic arid-based concrete

© SAGE Publications. In this article, the results of the hygroscopic characterization of a building material called 'picón', consisting of cement mortar and pyroclastic deposits from volcanic eruptions, are presented. The material obtained is used for the manufacture of blocks used in the construction of buildings in the Canary Islands. Picón is a heterogeneous material with uncontrolled particle size, having a pore system of very scattered sizes, what affects the moisture behaviour of the blocks. This heterogeneity results in a pore structure that affects the determination of the moisture properties of the material. In this work, this difficulty is faced, separately studying the pore structure of the cement paste and the aggregates, to come to a better interpretation of the concrete behaviour. The results indicate that the pore structure of the heterogeneous concrete differs from what could be expected from separately obtained porosimetry of each component of the concrete.status: publishe

Hygroscopic inertia influence on indoor environments : moisture buffering

In recent years great advances have been made, both in terms of regulation and technology, regarding the thermal behavior of buildings. However, a sustainable building, in addition to being energy efficient, must also ensure adequate hygroscopic performance, so as to guarantee adequate indoor air quality and comfort. As well as thermal inertia plays a very important role in the energy demand of buildings, the hygroscopic inertia of their enclosures is a regulating element in the hygroscopic balance of their interior environments, which, when properly used, can regulate the abrupt oscillations of relative humidity inside. In particular, the inner layer of the enclosures of a building interacts with the interior environment adsorbing and desorbing moisture as a function of the relative humidity of the indoor air, and therefore, that damping capacity constitutes an important term on the moisture balance of the spaces. In this paper the influence of the moisture buffering capacity of different materials on inside relative humidity is studied for different climates, ventilation rates and vapor production schemes by numerical simulation.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers

Characterization of wet granular avalanches in controlled relative humidity conditions

This work focuses on the influence of the relative humidity (essentially due to atmospheric conditions) on themany granular media behaviours. To this end, the experimental evolution of the avalanche characteristic anglesof continually tilted granular packing was studied for a wide range of relative humidities in very well controlledconditions (between 5 and 90%). The stability angles were measured for fully developed avalanches. The relationshipbetween the relative humidity (ϕ) and cohesion of granular media (directly related to cohesion forcesbetween grains) was then established to identify the different cohesive states of a wet granular medium usinga reliable and reproducible testing methodology. Finally, a relationship between the hygroscopic equilibriumtime and the stability of the granular packing is discussed.Fil: Gomez Arriarán, I.. Universidad del País Vasco; EspañaFil: Ippolito, Irene Paula. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chertcoff, Ricardo Héctor. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; ArgentinaFil: Odriozola Maritorena, M.. Universidad del País Vasco; EspañaFil: Schant, R. de. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; Argentin