An investigation has been made of the mechanics of construction compaction degradation, the properties of mineral aggregates that influence degradation, and existing laboratory tests for evaluating degradation susceptibility. Field investigations consisted of concrete-base tests and soil-base tests. Laboratory tests investigated were the Los Angeles abrasion, the mechanical kneading compactor, repetitive loading, the modified AASHO, freeze-thaw, and absorption and specific gravity. Petrographic studies included megascopic and microscopic examination, X-ray analysis, differential thermal analysis, insoluble residue analysis, and chemical analysis. The greatest degradation to the aggregate mass occurs during the first compactor pass, with progressively less breakage resulting from each successive pass. Degradation and density are interrelated and are affected by each other. One-size materials are the most susceptible to degradation and dense-graded materials are the least susceptible. No single laboratory physical test can be used to evaluate aggregate degradation quality, although the Los Angeles test suffices for unweathered carbonate aggregates. Freeze-thaw action lowers the degradation quality of aggregates. Petrographic analysis is a reliable means of evaluating degradation quality and is recommended as a routine laboratory test.

Media Info

  • Pagination: 85 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00263976
  • Record Type: Publication
  • Report/Paper Numbers: #166 Tech Rpt
  • Files: TRIS
  • Created Date: Dec 31 1974 12:00AM