CHINLE CLAY TARGET OF RESEARCH CONTRACT

APPROXIMATELY 6,000 SQUARE MILS OF CHINLE CLAY ARE EXPOSED IN NORTHEASTERN ARIZONA. THE MATERIAL HAS A PLASTICITY INDEX OF 50 OR MORE AND IS UNSATISFACTORY AS A HIGHWAY SUBGRADE. THE DEPOSITS ARE FROM 5 TO 500 FEET DEEP. A NUMBER OF STUDIES HAVE BEEN MADE TO FIND A MEANS OF STABILIZING THE CLAY. THREE CONTROL METHODS SHOW PROMISE: (1) USE OF AN ION EXCHANGE METHOD BY INTRODUCTION OF POTASSIUM CHLORIDE IN THE TOP TWO FEET OF CLAY, WHICH IS EXCAVATED AND MIXED WITH THE CHEMICAL AND A WETTING AGENT; (2) USE OF AN ASPHALT MEMBRANE OVER THE SUBGRADE IN BOTH EMBANKMENT AND CUT; AND (3) USE OF FULL-DEPTH ASPHALT WITH AN ASPHALTIC MEMBRANE IN THE SHOULDER AND CUT DITCH. THESE METHODS ARE FEASIBLE FOR USE IN NEW CONSTRUCTION ONLY. FOR EXISTING ROADS, WHICH BUCKLE BADLY, AN ELECTRO-OSMOSIS TREATMENT SHOWS PROMISE IN SMALL FIELD TESTS. THIS INVOLVES INTRODUCTION OF POTASSIUM CHLORIDE IN SOLUTION UNTO THE SUBGRADE, PERMITTING ELECTRICAL FORCES TO MOVE MOISTURE HORIZONTALLY. RESEARCH INDICATES THAT THE SWELL PRESSURE OF THE CLAY IS MARKEDLY REDUCED BY THIS TECHNIQUE.

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  • Accession Number: 00233259
  • Record Type: Publication
  • Source Agency: Public Works
  • Files: TRIS
  • Created Date: Jun 18 1972 12:00AM