Beneficial Reuse of Foundry Sands in Controlled Low-Strength MaterialEPA Grant Number: U915330
Title: Beneficial Reuse of Foundry Sands in Controlled Low-Strength Material
Investigators: Dingrando, Jeffrey S.
Institution: University of Wisconsin - Madison
EPA Project Officer: Lee, Sonja
Project Period: September 1, 1998 through September 1, 2001
Project Amount: $34,000
RFA: STAR Graduate Fellowships (1998) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Engineering and Environmental Chemistry , Fellowship - Civil/Environmental Engineering
The objective of this research project is to: (1) assess the feasibility of using waste foundry sands as fine aggregate in controlled, low-strength material (flowable fill); and (2) categorize waste foundry sands based on performance in flowable fill to simplify mix design and increase opportunities for beneficial reuse of waste foundry sand.
A number of different foundry sands, representative of the foundry sands used in Wisconsin, were mixed with portland cement, fly ash, and water to create flowable fill. Mix performance was based on key criteria for flowable fill: flowability, setting time, and strength. First, components were mixed in various proportions until a minimum flow was achieved. Minimum flow refers to a condition in which the material is self-compacting, self-leveling, and will flow around obstructions. The changes in flow over time, because of thixotropic effects of the clay fraction of foundry sand and/or cementation effects, also were evaluated. Second, mixes were tested for strength and strength gain over time with unconfined compression tests. Achieving some minimum strength is required to accept loads such as pavement and traffic. However, limiting the strength to some maximum also is critical because most flowable fill applications require the ability to excavate the material at a later date. The effects of environmental factors (freeze-thaw, wet-dry) on the durability of the materials also were evaluated. Changes in sand type, cement content, fly ash content, and water content were correlated to performance, and conclusions were made about the influence of each factor. The applicability of flowable fill test methods, which are relatively new, also was examined, and recommendations were made for future testing procedures.