MICROSCOPIC AND X-RAY DIFFRACTION EXAMINIATION OF BASALT TO DETERMINE FACTORS AFFECTING DURABILITY

Similar mineralogy and textures exist in the basaltic rock studied from four quarries in the Nestucca River area of northwestern Oregon. However, durability of the aggregates manufactured from these quarries differs greatly. This study, done by petrographic and X-ray analysis shows that no new minerals form during degradation. Existing delays such as nontronite, increase in percentage as degradation progresses. In contrast degradation did not occur in rocks containing analcite, a mineral which forms under conditions unfavorable to the formation of nontronite. It was also found that durability cannot be determined solely by percentages of weathering products found in the rocks as some studies have suggested.

Media Info

  • Pagination: 72 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00130710
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: FHWA-RD-74- 20 Final Rpt.
  • Files: NTL, TRIS, USDOT
  • Created Date: Apr 21 1976 12:00AM