An Engineering Test Program of MSW Ash Mixed with Quarry Tailings for Use as a Landfill Construction Material

The state of Hawaii has limited resources in terms of construction grade natural materials and space available for municipal landfills. Aggregate must be quarried by blasting of basalt from hillsides or excavation of ancient corals. Natural landfill soil materials must also be excavated, often from environmentally and/or ecologically sensitive areas. On the island of Oahu, municipal solid waste (MSW) is incinerated to reduce its total volume, thereby conserving valuable landfill space. Local quarries also landfill their waste products. If the State can use these wastes as construction materials, land will be conserved, money will be saved. The University of Hawaii developed a test program to identify engineering properties of several ratios of MSW ash mixed with two different local quarry tailings. Each quarry fine was mixed with the ash at different ratios and tested for strength, permeability, gradation, and swell potential. The objective of the test program was to select a potential material for use as a landfill final cover. Results of tests qualify possibilities of a new construction material.