SHALE SUITABILITY RESEARCH - PHASE II

THIRTY-FOUR SAMPLES, WHICH INCLUDED 31 SHALES, 2 SILTSTONES, AND ONE FINE-GRAINED SANDSTONE, WERE COLLECTED FROM SITES THROUGHOUT CENTRAL AND SOUTHERN PENNSYLVANIA. THESE SAMPLES ARE SUBJECTED TO THREE AREAS OF INVESTIGATION - DURABILITY TESTS, PHYSICAL PROPERTY DETERMINATIONS, AND MINERALOGICAL AND COMPOSITIONAL ANALYSES. BY COMPARING THE RESULTS OF SIMILAR TESTS WHICH WERE RUN ON KNOWN SOUND AGGREGATE, IT WAS FOUND THAT FOUR GEOLOGICAL UNITS CONTAIN SHALES OF SUFFICIENT DURABILITY TO BE SUITABLE FOR USE AS GRANULAR MATERIAL IN HIGHWAY CONSTRUCTION. THESE UNITS ARE THE UPPER DEVONIAN MARINE BEDS, THE GETTYSBURG FORMATION (HEIDLERSBURG MEMBER), THE KINZERS FORMATION, AND THE ORISKANY FORMATION (SHRIVER). THE DATA FROM ALL THE TESTS WERE ANALYZED TO DETERMINE THE DEGREE OF CORRELATION BETWEEN THE VARIOUS PARAMETERS. IN ADDITION THE GYRATORY, WET-DRY, AND WASHINGTON DEGRADATION TEST RESULTS WERE WEIGHTED AND COMBINED TO PRODUCE A DEGRADATION FACTOR (DF) WHICH WAS THEN COMPARED TO THE PHYSICAL PROPERTY VALUES AS WELL AS TO THE PERCENTAGES OF CONSTITUENT MATERIALS IN THE SHALES. FROM THESE STUDIES AN APPARENT RELATIONSHIP WAS FOUND BETWEEN DURABILITY, (DF), BULK SPECIFIC GRAVITY, AND PERCENT ABSORPTION. RESULTS OF THE ETHYLENE GLYCOL TEST ALSO CORRELATE WELL WITH DURABILITY. TO STUDY THE CONTRIBUTION OF THE VARIOUS CLAYS TO THE BREAKDOWN OF THE SHALES, A CLAY FACTOR (CF) WAS DERIVED BY WEIGHING THE PERCENT ILLITE, THE ILLITE/KAOLINITE RATIO, PERCENT MONTMORILLONITE, AND PERCENT SCRICITE AND COMBINING THE RESULTS. A GOOD CORRELATION WAS OBTAINED BETWEEN CF AND DF, WHICH SEEMS TO SUBSTANTIATE THE ACCURACY OF THE CF. BY STUDYING THE PETROGRAPHY OF THE SPECIMENS BEFORE AND AFTER TESTING, SOME IDEAS ABOUT THE MECHANISM OF SHALE DEGRADATION WERE OBTAINED. ALSO, IT WAS FOUND THAT LAMELLAE THICKNESS IS CLOSELY RELATED TO SHALE DURABILITY; VERY THINLY LAMINATED SHALES (LAYERS LESS THAN 0.5 MM THICK) ARE ALWAYS NONDURABLE (UNSUITABLE) AND "THICKLY"- LAMINATED SHALES (LAYER GREATER THAN 0.5 MM THICK) ARE GENERALLY GOOD TO EXCELLENT IN DURABILITY. A TENTATIVE SCREENING PROCEDURE FOR DISTINGUISHING DURABLE FROM NONDURABLE SHALES IS PROPOSED. /AUTHOR/

• Corporate Authors:

  Pennsylvania Department of Transportation

  1215 Transportation and Safety Building
  Harrisburg, PA  United States  17120

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Reidenouer, D R
• Publication Date: 0

Subject/Index Terms

• TRT Terms: Clay; Durability; Ethylene glycol; Granular materials; Illites; Kaolinite; Materials selection; Mineralogy; Montmorillonite; Petrography; Physical properties; Road construction; Shale; Specific gravity
• Old TRIS Terms: Degradation (Aggregate)
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00217497
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: Study No 68-23
• Files: TRIS, USDOT, STATEDOT
• Created Date: Jan 12 1972 12:00AM