Underground Air Duct to Control Rising Moisture in Historic Buildings: Improved Design and Its Drying Efficiency

Abstract

Abstract. The underground air ducts along peripheral walls of a building are a remediation method, which principle is to enable an air flow along the moist building structure's surface to allow a sufficient evaporation of moisture from the structure. This measure reduces the water transport (rising moisture) into the higher parts of the wall where the high water content in masonry is undesirable. Presently, underground air ducts are designed as masonry structures, which durability in contact with ground moisture is limited. The article describes a new design of an underground air duct, which is based on specially shaped concrete blocks (without wet processes, because the blocks are completely precast). The air duct from concrete blocks is situated completely below the ground surface (exterior) or below the floor (interior). Thanks to this, the system is invisible and does not disturb the authentic look of rehabilitated historic buildings. The efficiency of the air duct technical solution was verified by the results of tests (based on the measured moisture values) conducted on a laboratory model. The experimental study showed that the moisture in the masonry equipped with the presented underground air duct had decreased considerably compared to the reference sample, namely by 43 % on average. The experimental study was numerically validated through numerical simulations performed with the program WUFI 2D.

Textile Reinforced Concrete in Combination with Improved Self-Healing Ability Caused by Crystalline Admixture

“…Likewise, the authors of this article have written several papers dealing with selected problems in the field of crystalline waterproofing systems: crystalline admixtures and their effect on selected properties of concrete [ 33 ], description of crystalline coating properties [ 34 ], speed of the crystalline admixture’s waterproofing effect in concrete [ 35 ], interaction between the crystalline coating and carbonated concrete, durability of concrete with a crystalline admixture in the earth environment [ 36 ], the effect of crystalline admixture on concrete and cement mortar compressive strength, and the long-term sorption properties of mortars modified by a crystallizing admixture [ 37 , 38 , 39 ].…”

Czech Ww2 Concrete Fortifications: Corrosion Processes and Remediation Method Based on Crystallizing Coating

“…For this reason, a thorough moistening of the concrete before the coating application is necessary, but in the case of water leakage (which is a reason for the remediation), moistening is ensured by itself. Concrete with a crystallizing coating is completely effective against hydrostatic pressure as demonstrated by many successful laboratory tests presented in literature [13][14][15][16][17][18][19][20][21][22][23][24][25] and also by applications [26,27]. The "depth effect" of crystallizing coatings was verified by a specific laboratory test based on using the electrical resistivity method [28].…”

Criterios de diseño y caracterización de las cámaras de aireación, para el tratamiento y prevención de las humedades de capilaridad en edificios de interés patrimonial

“…Para forjados sanitarios: Kurnitski (2000), Ric ter y Stan k (2015). Para cámaras de aireación: Freitas et al 2008, Pazderka et al (2017). Aun así, la cantidad de datos experimentales que se tienen en campo es pequeña todavía (Franzoni, 2018), cuestión que se viene a paliar con la presente tesis.…”

“…La cantidad de vapor extraída durante 3 años fue de 29kg/m en el circuito sur y de 9kg/m en el circuito norte. Pazderka et al (2017) realizaron un modelo experimental en laboratorio, validado mediante simulación numérica WUFI 2D. Miden el incremento de la evaporación (sin considerar la influencia de las sales solubles) en un modelo de laboratorio que simula una cámara de ventilación (Figura 33).…”

“…Figura 33. Modelo experimental en laboratorio de cámara de aireación (Pazderka et al, 2017): A) Flujo de aire; B) Medición con sondas de resistividad eléctrica.…”