Measurement of the gas permeability of autoclaved aerated concrete in conjunction with its physical properties

The technique for determining the gas permeability of autoclaved aereted concret (AAC) which was developed here allows one to identify differences in the evolution of the porous structure caused by various manufacturing conditions. A comparison of permeability and compressive strength in relation to density illustrates a contradictory tendency on the part of these two physical properties i.e. as the raw density increases, compressive strength and permeability decline. Small cracks arising during the rising process result in decreased compressive strength in the direction of rising and an increased gas permeability perpendicular to that direction. This anisotropy in AAC can be more precisely illustrated by measuring the gas permeability than by determining the compressive strength, especially with lower classes of density.