In Situ Monitoring of Drying Process of Masonry Walls

Abstract

The in situ hygro-thermal behavior of a wet masonry wall during its drying process is presented in this paper. The considered wall is a part of a basement of a historic building that was subjected to renovation works. The building is located in the City of Łowicz (Poland). The drying process was implemented by applying the thermo-injection method and a novel prototype of the drying device used for this method. The dedicated acquisition system was developed to in situ monitor parameters of the drying process. The air temperature and relative humidity in various locations in the basement, temperatures and moisture contents at several points of the wet wall as well as the electrical parameters of the drying device were registered. Based on variations of the monitored parameters, the hygro-thermal behavior of the wall during drying was studied. After 6 days of drying, the wall temperature in the drying zone was increased to approximately 40–55 °C, while the moisture content was reduced to the mean level of 3.76% vol. (2.35% wt.). These wall parameters allowed for effective impregnation of the wall with the hydrophobic silicone micro-emulsion, which created horizontal and vertical waterproofing. Moreover, the specific energy consumption during the drying process defined as energy consumption divided by the mean volumetric moisture content drop (MC) between the initial and final state in the wall and by the length of the dried wall section was estimated to be 11.08 kWh/MC%/m.

Efficiency Comparison between Two Masonry Wall Drying Devices Using In Situ Data Measurements

“…The drying process was carried out by applying the thermo-injection method, which is a convective drying method [3,4]. In the first step of this method, at the internal side of the wall segment, a set of 20-mm drying holes every 15 cm and at an angle of 30 • from the horizon was prepared in 2 staggered rows.…”

“…If the excessive moisture is found in the building's elements, the building must be renovated. The renovation of wet masonry walls is divided into three steps [3]. In the first one, the excessive moisture is removed from the wall by applying the drying process.…”

“…Moreover, the improvement of the efficiency of the drying process of masonry walls may include activities such as optimization of the drying method parameters, proposing a new drying strategy or improvement of the drying device. However, no such activities were reported in the literature, aside from the work of Cieślikiewicz et al [3], who studied the hygrothermal behavior of a wet masonry wall in a historic building during its drying and assessed the energy consumption of the process.…”

“…The mentioned studies mostly dealt with monitoring the moisture accumulation and transfer in building elements under their normal or standard usage. Only a few papers [3,4,15] were related to the analysis of a forced drying process. The state of the art is still missing wide studies of the hygrothermal behavior of the masonry wall during its forced drying at a real scale with analysis of the energy efficiency of this process and its optimization.…”

Procedures and Methodologies for the Control and Improvement of Energy-Environmental Quality in Construction

“…Cieślikiewicz et al in their study [8] monitored in situ the drying process of masonry walls and recorded the changes in the temperature and moisture as part of the renovation the historical building's basement. Vaisi et al [9] provided a new thermal energy benchmark for university buildings focusing on monthly resolution in order to improve the accuracy of national action plans and their realization for energy-efficient built environment.…”