Laboratory Evaluation of Crushed Glass–Dredged Material Blends

Abstract

A comprehensive laboratory evaluation of blending 9.5mm(3∕8in.) minus curbside-collected crushed glass (CG) with dredged material (DM) was conducted to evaluate their potential for beneficial use as fill materials for urban applications. Tests were performed on 100% CG (USCS classification SP) and 100% DM (OH) specimens and 20∕80, 40∕60, 50∕50, 60∕40, and 80∕20 CG–DM blends (dry weight percent CG content reported first). The addition of 20% CG resulted in a 10–20 point (33–67%) reduction in wopt while increasing the dry density by approximately 1–3kN∕m3 for standard and modified levels of compaction, respectively. Simultaneously, the compressibility of the DM was reduced by approximately 50% and the hydraulic conductivity was reduced by 12 order of magnitude. The addition of 20% CG significantly decreased the moisture content and significantly improved the workability of the 100% DM, where workability refers to the ease of handling, transport, placement, and compaction of the CG–DM blends (compared to 100% DM). CIŪ triaxial strength testing indicated effective friction angles of 34 and 37° for 100% DM and CG compacted to a minimum of 95% relative compaction by ASTM D1557, respectively. A peak effective friction angle of 39° occurred for the 60∕40 and 80∕20 CG–DM blends which were also 1 and 3 orders of magnitude more permeable than 100% DM, respectively. Related increases in cv resulted in decreased times required for consolidation. The range of properties obtainable by the CG–DM blends offers a versatility that allows for the design of fills that can be potentially optimized to meet multiple design parameters (e.g. strength, settlement, drainage, or higher CG or DM content).