This report provides technical data regarding the reuse of excess foundry sand. The report addresses three topics: a statistically sound evaluation of the characterization of foundry sand, a laboratory investigation to qualify excess foundry sand as a major component in controlled low-strength material (CLSM), and the identification of the best methods for using foundry sand as a replacement for natural aggregates for construction purposes, specifically in asphalt paving materials. The survival analysis statistical technique was used to characterize foundry sand over a full spectrum of general chemical parameters, metallic elements, and organic compounds regarding bulk analysis and leachate characterization. Not limited to characterization and environmental impact, foundry sand was evaluated by factor analyses, which contributes to proper selection of factor and maximization of the reuse marketplace for foundry sand. Regarding the integration of foundry sand into CLSM, excavatable CLSM and structural CLSM containing different types of excess foundry sands were investigated through laboratory experiments. Foundry sand was approved to constitute a major component in CLSM. Regarding the integration of foundry sand into asphalt paving materials, the optimum asphalt content was determined for each mixture, as well as the bulk density, maximum density, asphalt absorption, and air voids at Nini, Ndes, and Nmax. It was found that foundry sands can be used as an aggregate in hot-mix asphalt production, but each sand should be evaluated individually. Foundry sands tend to lower the strength of mixtures and also may make them more susceptible to moisture damage. Finally, traditional anti-stripping additives may decrease the moisture sensitivity of a mixture containing foundry sand, but not to the level allowed by most highway agencies.
Key WordsFoundry sand, hot-mix asphalt, controlled low-strength material, aggregate, asphalt paving materials, leachate characterization, survival analysis, moisture damage, bulk density, optimum asphalt content
INTRODUCTIONThis report is organized in 10 chapters. The first chapter includes the problem statement, research objective, and work plan of the study. Chapter 2 presents the literature review. Chapters 3 through 5 are concentrated on the characterization of foundry sand. Chapter 6 describes the characteristics of the materials and the test methods used in the laboratory studies. Chapters 7 and 8 are dedicated to the experimental investigation, results, and discussion. Chapter 9 presents conclusions based on the previous chapters, and Chapter 10 details recommendations for future studies.
Problem StatementOne of the most pressing problems facing the metal casting industry today is the disposal of foundry byproducts. The annual generation of foundry by-product was reported to range from 9 to 13.6 million tons in 1999 [Bol'shakov and Winkler 2001, DOE 1999]. An estimated 6-10 million tons of excess foundry sand is disposed of annually in the United States. These byproduc...
