Foundry Sands in Highway Construction

The largest volume of waste foundry sand is used in geotechnical applications. These applications are concerned with the engineering properties of earth materials and construction, and include embankments and structural fills as well as road bases, landfills, highway construction, and barriers.

The specifications for using foundry sands as fill materials generally have been the same as the specifications for typical backfills. These specifications are universal and vary depending on the use of the material, i.e. embankment, structural fill, roadway sub-base, and foundation sub-base, and consist of compacting the material in layers to a minimum percentage of the maximum dry unit weight. The material should also be compacted to a minimum unit weight of 14.9 kN/m3 (95 pcf) and at a water content around optimum water content. Most specifications require a maximum liquid limit of 65%, and a plasticity index less than the liquid limit minus 30. Most foundry sands satisfy these requirements and therefore are eligible to be considered as construction fill materials.