Evaluation of Foamed Glass Aggregate for Roadway Embankment Applications

Lightweight fill materials play critical roles in building infrastructure on challenging sites. Foamed glass aggregate (FGA) is a lightweight option that has attracted much attention lately. FGA is a processed recycled aggregate made from waste glass. The process involves grinding the glass into powder and melting it at a high temperature (e.g., 1,600°F) with a foaming agent (e.g., 2% by weight). In addition to its low compacted unit weight, FGA possesses several unique engineering properties, such as a high friction angle, good thermal insulation, high permeability, easy placement, and so forth. With these properties, the utilization of FGA could be a sustainable practice that contributes to the reduction of fill settlement over soft ground and environmental preservation by the reuse of waste glass. However, as with any emerging or unconventional material, a comprehensive engineering study of FGA is essential before its widespread application to prevent unsatisfactory performance. To that end, two types of FGA material (produced using either a dry or wet foaming agent) and two conventional soils (sand and clay, used as references) were procured for laboratory experiments. These experiments covered basic FGA characteristics, including gradation and volumetric properties, followed by mechanical properties such as axial compression compaction, one-dimensional consolidation, dynamic triaxial, and direct shear. In addition, a pilot fill construction was undertaken using FGA to determine the field compaction acceptance criteria. Results indicated that FGAs are viable lightweight fill materials. Further research is needed to monitor FGA performance through full-scale construction projects.