Geotechnical performance of a highway embankment constructed using waste foundry sand

A highway embankment was constructed near Auburn, Indiana, using waste Foundry sand (WFS) as a demonstration project for the Indiana Department of Transportation (INDOT). Laboratory testing before construction indicated the WFS is best characterized as a silty sand, with good strength properties and a relatively low hydraulic conductivity, Field instruments were installed in three embankment sections composed of WFS, clay, and clean sand. Instrumentation for the WFS section consisted of vertical, and horizontal inclinometers, settlement plates. total pressure cells, and piezometers. Measurements up to 21 months after WFS placement showed small vertical and horizontal deformations. Comparison of compaction testing methods for WFS indicated some corrections may be necessary when using a nuclear density gauge. Field and laboratory tests indicated the WFS had a hydraulic conductivity on the order of 10(-7) m/s. Standard penetration testing of the completed embankments showed blow counts for the WFS were comparable to those for the clean sand. The economic benefits gained by the foundry were estimated to be $640,000, possibly higher when considering siting and construction costs for a new landfill. Savings in material costs for INDOT were estimated to be $145,000 as a result of using WFS for this project.