An Investigation of the Status of By-Product Fines in the United States (ICAR-101-1/98)

The handling and disposal of fines produced as a result of the aggregate crushing and production process are some of the major problems facing the aggregate industry today, having both economic and environmental implications. This report describes a major effort undertaken to quantify and characterize these fines, their location, character, and sales.A literature review was carried out to determine what is already known about the various aspects of the problem. Based on this literature review and interaction with the aggregate industry representatives, researchers created a "fines database" to quantify and characterize information about these materials. An "information booklet" was developed, sent to aggregate producers as the data collection instrument, and subsequently mailed to aggregate producers all over the country and abroad. Responses from 154 companies covered 362 plants. Researchers arranged and analyzed the data received. This report presents the first round of data analysis.The responding plants represented a total of about 287 million tons of annual production of aggregates. The responses showed that about 470 to 500 million tons of minus 3/8" fines are produced annually, out of which 90 to 100 million tons are not marketed. In the case of minus #200 fines, these estimates were about 100 to 110 million tons and 75 to 80 million tons, respectively. Also, based on the responses, the estimated amounts of stockpiled minus 3/8" fines were 300 to 325 million tons while in the case of minus #200 fines, the estimated amounts were about 400 million tons. Asphalt-related applications seemed to be the only widespread use of minus 3/8" fines. There seemed to be no widespread uses for minus #200 fines. In the case of minus 3/8" fines, the respondents reported ready-mix flowable fills, cement treated subbases, and low cost masonry uses as the most promising potential uses. For minus #200 fines, researchers identified ready mix flowable fills and solid waste landfills as the most promising potential uses.Based on the responses and given the environmental and economic implications of the problem, a major research effort was undertaken to determine and document the physical and chemical characteristics of by-product fines and to find high volume uses for them. To deal with the problem effectively, marketing aspects were addressed along with the technical issues.