This study was conducted to find out the structural characteristics of a lightweight air-mixed soil (LWS). The LWS was manufactured with insitu soil categorized with silty marine sediment. This LWS was used for a road embankment, which was constructed on 10.9 ~ 20.5m deep soft marine clay. The structure characteristics were analyzed in detail. Various size pore bubbles are existed inside the LWS, and its distribution with a location is almost constant. A numerous tiny cracks are existed inside the pore bubbles so that the LWS can be saturated due to water. To examine the effect of structure characteristics on the change of density of LWS due to water, the density was checked for several cases. The density of LWS is varied and thus it is required to pay attention on this phenomenon during structure design and maintenance of the LWS.
A lightweight air-mixed soil (LWS) is prepared by mixing air bubbles and water with construction waste or in-situ soils and cement (Fig. 1(a)). A slurry density is generally adjusted to about 10kN/m3 but may be vary with several required conditions or quality control factors (for instance, compression strength, slump, dissipation air bubble, and so on). LWS has several advantages that it is able to reduce the load affecting on the ground because it is lighter than soil, it is able to move by pumping because its fluidity is high and it is easy to construct because it does not need compaction process. It has been recognized as an effective material for embankment construction on soft ground, back filling of a retaining wall, backfilling of a structure, stuffing of settlement ground and so on. Due to these advantages, it has potential uses (Highgradesoil Research Consortium, 2005; Hayashi et al., 2002; Yahima et al., 2006) (Fig. 1)
