ABSTRACT
Abstract The dependence of autoclaved concrete with variable amount of gypsum and of different cure times was investigated in the low temperature region down to -120°C. The dynamic elastic modulus and the damping maximum were measured. In addition calorimetric data and pore size distributions with mercury porosimetry and water vapor adsorption isotherms were obtained. The results show a correlation of the change in the pore size distribution with the temperature shifts of the enthalpic and mechanical properties. Keywords: autoclaved concrete, gypsum, dynamic elastic modulus, damping maximum, calorimetry, phase transitions, low temperature, adsorption
1 Introduction
Environmental pollution is a general problem. To reduce the sulfate emissions in coal power plants the emissions are filtered. Sulfuric acid is transformed to gypsum when calcium carbonate is added. However, the amount of this produced gypsum has increased in such a way that problems have arisen concerning the disposal. Therefore, it is of common interest to use this gypsum as an additive in concrete or mortar. In this contribution the effect of varying quantities of gypsum in autoclaved concrete in the low temperature region is investigated. Autoclaved concrete is used for the production of parts of prefabricated houses.
