concrete

This paper presents results of air leakage measurements on brick walls and concrete block walls, used as outer or inner leaf of a cavity wall. The results are obtained using a pressure box on a series of test walls. The variable parameters that are examined: workmanship, pointing of the joints andplastering of the inner leaf. Out of the results can be concluded that, in general, only a plastered wall can guarantee a sufficient airtightness.

Approximately 40% of the energy consumption in Sweden is utilized in the heating of buildings. In order to reduce the amount of energy utilized for heating purposes, more stringent thermal insulation requirements for buildings were introduced.

Indoor radon concentrations have been measured in a 13 year old two story concrete building of the University of Texas at Dallas. Variations of the radon concentration from the basement to the second floor in offices, classrooms, laboratories, storage rooms, corridors and other locations have been measured. Dependence of the above concentrations on the location and ventilation rates have been studied.

Measurements made in Finland have shown that the airtightness of many small houses is lower then the level of requirements specified in Sweden. States that the most important areas for sealing up external walls in concrete structures are the joints in the internal shell, the joints between concrete and timber structures, and the joints between door and window frames. All these areas can be made airtight by using appropriate materials and construction methods. In general, the air tightness of small concrete houseshas been found to be good and to comply with the specified requirements.

Describes tests performed on laboratory manufactured and prefabricated concrete specimens, to determine air leakage rates through cracks. Shows the expected increase of air leakage for increasing crack width and the decrease for increased element thickness. Appropriate theoretical assumptions are described, and the results show relationships for the calculation of the magnitude of air leakage through cracks.