Crushed stone dust is stone powder generated in the production process of crushed stone, and crushed stone dust prepared to a maximum particle size of 2.5 mm or less is specified as "Screenings (F-2.5)" by JIS A 5001 (Crushed Stone for Road Construction). "Screenings" is mainly used as a fine aggregate of asphalt concrete for paving. Since "Screenings (F-2.5)" is a product of the stone crushing factory, the quality is relatively stable, and the fine particle fraction (75 µm or less) is also contained at about 0 to 20%, and therefore, the applicability as soil material is considered to be high. In the preliminary study, we investigated the applicability of "Screenings (F-2.5)" as base material for the surface impermeable soil liner material (soil-bentonite mixture and cement stabilized soil), and we got a suggestion that the target water permeability could be achieved by appropriately setting the types and amounts of bentonite and cement-based materials when the target compaction degree was set to Dc 95 % or more and the target water permeability coefficient in laboratory test was set to 1×10-7 cm/s or less (1×10-9 m/s or less) . In this paper, we introduce the result of proportion test carried out for the purpose of actually applying soil-bentonite mixture and cement stabilized soil using crushed stone dust (Screenings) as a base material to surface impermeable soil liner construction work.
