GEOLOGIC CHARACTERISTICS OF ILLINOIS GRAVEL DEPOSITS AFFECTING IDOT FREEZE-THAW TEST RESULTS

One of the most serious problems in portland cement concrete pavements in many states is D-cracking which occurs adjacent to joints. Illinois has made a concerted study of this problem over the years and has found that a freeze-thaw test on concrete beams is a good means of identifying aggregates which are troublesome. Nevertheless, this problem still exists. This report concerns a study of gravel aggregates to attempt to determine the individual rock types which may cause a gravel source to be unsatisfactory. Sixteen study samples were selected from 15 sources. A wide variety of tests were made, with separations of individual gravels into their several rock types. The results are presented in some detail, along with conclusions and recommendations. Some of the more pertinent findings are: the most expansive rock types in the gravels were chert, especially with a specific gravity of less than 2.35, and to a lesser degree ironstone, along with silty dolomite and weathered carbonate; very small amounts of expansive pebbles can cause significant beam expansion; the location of the "bad" and "good" pits in geological areas is indicated; and it seems that certain processing techniques, such as using a vertical impact crusher, can eliminate significant amounts of expansive rock.

• Supplemental Notes:
  • Data for this citation obtained from "Research and Publications Review", Minnesota Department of Transportation, No. 88-9, September 1988.
• Corporate Authors:

  Illinois Department of Transportation

  126 East Ash Street
  Springfield, IL  United States  62706
• Authors:
  • Masters, J M
  • Evans, R D
• Publication Date: 1987-3

Media Info

• Pagination: 84 p.

Subject/Index Terms

• TRT Terms: Aggregates; Aggregates by source; Cherts; D cracking; Dolomite; Freeze thaw tests; Geology; Gravel; Gravelly soils; Silts
• Uncontrolled Terms: Aggregate sources
• Old TRIS Terms: Aggregate characteristics; Expansive rock; Processing; Silty gravels
• Subject Areas: Geotechnology; Highways; I36: Aggregates;

Filing Info

• Accession Number: 00475948
• Record Type: Publication
• Report/Paper Numbers: Project IHR-416
• Files: TRIS
• Created Date: Sep 30 1988 12:00AM