STRENGTH OF CONCRETE CONTAINING MUNICIPAL SOLID-WASTE FLY-ASH

The properties of concrete containing fly ashes obtained from the burning of municipal solid waste (MSW) were determined. Variables included the type of fly ash [from a mass-burn plant or from a refuse-derived fuel (RDF) plant], two different burning conditions of the RDF fly ash, the amount of fly ash in the concrete with cement replacement amounts up to 60 percent, and the addition of a set-accelerating admixture. The test results include properties of the fresh concrete, cylinder compressive strengths at ages from 3 to 90 days, and time of set. Test results indicate that: (1) the RDF fly ash produced concrete with strengths comparable to the control concrete at replacement levels up to 45 percent; (2) the difference in burning conditions of the RDF fly ash had no significant effect on the concrete strength; (3) the mass-burn fly ash produced significantly lower concrete strengths; (4) the MSW fly ashes significantly increased the concrete setting time; and (5) high dosages of a set-accelerating admixture reduced the setting time of MSW fly ash concrete.