Effect of foam volume on penetration parameters of foamed concrete

Abstract

In this research, the effect of porosity owing to foam on the penetration parameters of foamed concrete, including absorption and chloride ingress, is evaluated. The penetration parameters of foamed concrete are determined using a water/cement (w/c) ratio of 0.5 and foam contents of 20, 35 and 50%, and then compared with the base mix without foam and with an equal w/c ratio. In addition, the penetration parameters of the structural-grade foam concrete with a w/c ratio of 0.4 and foam volume of 20% are determined and compared with a conventional concrete of equal strength. The results show that, with an increase in foam porosity, the volumetric absorption and the capillary absorption coefficient are decreased, and that therefore chloride diffusion is increased. The discrepancy is owing to the presentation of absorption results based on a total concrete volume. By considering these results based on paste volume, which is the penetrable phase, absorption results show the same trend as the chloride diffusion results. Increased foam volume results in larger and more connected air voids. Meanwhile, the structural-grade foam concrete has a similar performance to the base mix, and also shows less penetrability relative to conventional concrete of equal strength.