Cost-effective uses of lightweight aggregate made from dredged material in construction

"January 2018."; "Report No. FHWA/OH-2017-47"--Page 2.; Includes bibliographical references (pages 60-64 of Final report).; Final report.; Sponsored by Ohio Department of Transportation, Research Section; State Job Number 135327Final report (64 pages) -- [Fact sheet] (2 unnumbered pages).Lightweight aggregate (LWA) can be used in concrete to reduce its self-weight and improve its workability and durability. It could potentially be used as borrow for embankment construction, which is expected to reduce the stresses on the subgrade foundation and reduce bridge approach slab settlement. However, the average estimated cost of LWA in U.S. is $67.5/ton, which is significantly higher than the costs of conventional aggregates. Dredged sediment has been identified as a raw material for LWA production, which may dramatically reduce the cost of LWA. Annually, 1.5 million cubic yards of sediments are dredged from Ohio harbors. This study evaluated the quality of dredged materials taken from the Harbors of Cleveland and Toledo, and their suitability to produce LWA. Engineering properties of LWA, including specific gravity, loose bulk density, friable particles, organic impurities, abrasion resistance, undrained cohesion, free swell, and compressibility were tested in the lab to evaluate its potential for use as a construction material. LWA has been successfully produced in the lab using dredged materials taken from the Harbors of Cleveland and Toledo. Most of their engineering properties met ASTM and ODOT specification values. Based on testing performed in the study, leaching of heavy metals were determined to not be a concern. While the Cleveland samples failed in the abrasion resistance test, the Toledo samples exhibited an excellent potential to be used in construction. The sustainability study concluded that a cost competitive LWA could be fabricated using the dredged material in mass production. The environmental impacts of the dredged material LWA are expected to be lower than the conventional ones made from expanded shale, clay, or slate