Investigation of foam volume on the penetration parameters of foamed concrete

Effect of foam porosity on absorption, capillary absorption and chloride ingress was studied. Performance of mixes with w/c ratio of 0.5 and foam contents of 20, 35 and 50% were determined and compared to those of a base mix with the same proportions but without foam incorporation. A structural grade foam concrete with w/c ratio of 0.4 and foam content of 20% was also considered together with a conventional concrete of equal strength level. The results show that foam incorporation results in decreased absorption and capillary absorption and increased chloride diffusion. The discrepancy is due to presentation of absorption results on total concrete volume basis. By considering these results on paste volume basis, which is the penetrable phase, absorption results show the same trend as the chloride diffusion results. Incorporation of 20, 35 and 50 percent foam into the base mix resulted in increases of 12, 27 and 50 percent in paste absorption and 18, 55 and 155 percent in chloride diffusion values respectively. Increased foam volume resulted in larger and more connected air voids. Despite the negative effect of foam incorporation on penetration characteristics, the structural grade foam concrete with its lower w/c ratio achieved similar levels of performance as the base mix and performed better than the conventional concrete of equal strength level.