Air entrapment and reaction with absorbed liquids on the absorption of aerated concrete

Abstract

Aerated concrete exhibits anomalous water transport, similar to mortar and concrete. Several factors, including water sensitivity, air entrapment, and gravity, are considered to be the causes; however, they are currently not quantitatively understood. This study aimed to clarify the mechanisms underlying the anomalous absorption of aerated concrete through liquid absorption experiments and numerical simulations of liquid and air transfer. The experiments showed that, unlike mortar and concrete, aerated concrete exhibited decreasing absorption rates during the initial stage of absorption, even when organic liquids were absorbed. A comparison between the calculations of simultaneous air and liquid transfers and those of single-phase water transfer in a material revealed that increases in water content in the high-water-content region were significantly reduced by air-pressure buildup. Therefore, the water absorption of aerated concrete, which is characterized by coarse aerated pores, is sensitive to air entrapment in addition to the water sensitivity of the cement component.