Turning Mud into Suitable Fill: Amending OH, ML-MH and CH Soils with Curbside-Collected Crushed Glass (CG)

The US Army Corps of Engineers (USACE) and various port authorities face many challenges with managing dredged material (DM) in their confined disposal facilities (CDFs). At the same time, quarries, mining companies, and other industrial concerns face serious challenges with managing fines. Chief among these challenges is identifying beneficial uses for soft compressible fine-grained soils (and/or residuals) such as ML, CL, MH, OH and CH soils as defined by the Unified Soil Classification System (USCS). Recent studies by Wartman et al. (2004a,b), Grubb et al. (2006 a,b) and Malasavage et al. (2006) provide the basic engineering and construction properties of 9.5 mm (3/8") minus curbside-collected crushed glass (CG) blended with these materials to demonstrate the potential use of the CG-soil blends in geotechnical construction. Select laboratory tests along with field verification illustrate the versatility of using CG to dramatically alter the properties of soft-marginal soils which, with basic pugmilling technology, can revolutionize materials selection, use and evaluation criteria. For example, switching from OH to CH soils at the same CG content, can mean a difference in K of 10^–4 cm/s, φ'_CIŪ of 13°, or γ_d,max of 15 lb/ft³, not to mention significantly different compressibility. This can enable the geotechnical design consultant with a soils improvement strategy to hand-craft fill materials for various site uses, often without changing the basic components of the blending operation. Comparisons to traditional blends of gravel/sand with fine grained soils illustrate that CG can achieve similar objectives and performance, and that the use of a "recycled material" is comparable to conventional aggregates for geo-mechanical stabilization of soft, fine-grained soils. These concepts have broad implications for those organizations confronted with long-term fines management issues and large fill projects.