Field Evaluation of Crushed Glass-Dredged Material Blends

Based on the laboratory results reported in a companion paper, three crushed glass-dredged material (CG-DM) blends were prepared and evaluated in the field to explore the feasibility of using CG-DM blends in general, embankment and structural fill applications. A trailer-mounted pugmill successfully prepared 20/80, 50/50, and 80/20 CG-DM blends (dry weight percent CG content reported first) within a tolerance of (plus-minus)5 dry % by weight of the targeted percentages. Blending criteria were routinely met at pugmill throughputs up to 1,500 m^3/day. The constructed 20/80 CG-DM embankment was compacted to a minimum of 90% modified Proctor compaction, whereas the 50/50 and 80/20 CG-DM embankments were constructed to a minimum of 95% modified Proctor compaction. Twenty to 80% CG addition to DM resulted in 1.5-5.5 kN/m ^3increases in field dry densities above 100% DM, densities not achievable with other DM stabilization techniques such as Portland cement, fly ash, and/or lime (PC/FA/lime) addition. CG substantially improved the workability of DM allowing construction with conventional equipment and three person crew while achieving very consistent and reproducible results during a timeline of frequent and heavy precipitation events. The 20/80, 50/50, and 80/20 CG-DM embankments were characterized by average cone tip resistances on the order of 1.0, 1.5, and 2.0 MPa, respectively. An environmental evaluation of 100% CG, DM and 50/50 CG-DM blend samples coupled with an economic analysis of a scaled-up commercial application illustrated that the CG-DM blending approach is potentially more cost effective than PC/FA/lime stabilization approaches. These features of CG-DM blending make the process attractive for use in urban and industrial settings.