FIELD MEASUREMENT OF DYNAMIC ELASTIC MODULI OF MATERIALS IN FLEXIBLE PAVEMENT STRUCTURES

IN AN EFFORT TO ADD TO THE ALREADY GROWING BACKGROUND OF INFORMATION RELATING TO NONDESTRUCTIVE METHODS OF TESTING SUCH AS THE DYNAMIC METHOD, A SERIES OF TESTS HAS BEEN ACCOMPLISHED USING THE SMALL HIGH FREQUENCY VIBRATOR ON SOME INDIVIDUAL HIGHWAY FIELD PROJECTS. IN THIS PROCESS, THE HIGH FREQUENCY VIBRATOR IS USED TO IMPOSE A CYCLIC FORCE ON THE SURFACE OF THE PAVEMENT AND AN ELECTRONIC PICKUP USED TO DETERMINE THE WAVE LENGTH AND VELOCITIES OF WAVES TRANSMITTED THROUGH THE COMPONENT LAYERS OF THE PAVEMENT. THE TECHNIQUE INVOLVED IS THE SAME AS THAT PREVIOUSLY ESTABLISHED IN VIBRATION MEASUREMENTS ON PAVEMENTS IN EUROPE AS WELL AS IN THE UNITED STATES. IN THE PRESENT PROGRAM, TESTS WERE MADE AT COLORADOS EXPERIMENTAL BASE PROJECT AND ALSO ON SELECTED HIGHWAY PAVEMENTS INCLUDED IN THE MINNESOTA SATELLITE PROGRAM. TESTS WERE STARTED IN THE FALL OF 1965 AT BOTH LOCATIONS AND THE MEASUREMENTS WERE THEN REPEATED IN THE SPRING OF 1966. AT THE COLORADO PROJECT IN WHICH A SERIES OF PAVEMENTS CONTAINING ASPHALT-STABILIZED SAND BASES IS BEING COMPARED WITH THE STANDARD GRANULAR BASE TYPES, RESULTS OF THE DYNAMIC TESTS INDICATE THAT DIFFERENT PATTERNS OF WAVE LENGTH VERSUS VELOCITY ARE OBTAINED FOR PAVEMENTS CONTAINING THE RELATIVELY THICK ASPHALT BASE LAYERS THAN ARE OBTAINED FOR THE GRANULAR BASE TYPES. DIFFERENCES BETWEEN THE PROPERTIES OF PAVEMENTS IN THE SEPARATE TRAFFIC LANES ARE ALSO DETECTED IN THE DYNAMIC TESTS AS WELL AS A SIGNIFICANT INFLUENCE EXERTED BY THE PAVEMENT TEMPERATURE. THESE DIFFERENCES ARE EXPRESSED IN THE MODULI OF ELASTICITY CALCULATED ON THE BASIS OF THE VELOCITY MEASUREMENTS. IN THE MINNESOTA TESTS, WHICH ENCOMPASSED A WIDE VARIETY OF PAVEMENT TYPES IN USE THROUGHOUT THE STATE, DIFFERENCES IN THE VELOCITY RESPONSE OF THE INDIVIDUAL TYPES IS AGAIN ILLUSTRATED. PAVEMENTS WITH RELATIVELY THIN SURFACES TEND TO PERMIT THE IDENTIFICATION OF PROPERTIES OF THE GRANULAR BASES BENEATH, WHEREAS THE PRESENCE OF A THICK LAYER OF ASPHALT STABILIZED MATERIAL TENDS TO OBSCURE THE PROPERTIES OF ANY OTHER LAYERS BELOW. /AUTHOR/

• Supplemental Notes:
  • Supplement, PREPRINT VOL, PP 58-72, 7 FIG, 4 TAB, 13 REF
• Authors:
  • Metcalf, C T
• Conference:
  • Intl Conf Struct Design Asphalt Pvmts
• Publication Date: 1967-1

Subject/Index Terms

• TRT Terms: Asphalt; Base course (Pavements); Dynamic modulus of elasticity; Field tests; Flexible pavements; Granular materials; High frequency; Materials; Thickness; Velocity; Vibration devices; Wavelength
• Uncontrolled Terms: Field measurements
• Old TRIS Terms: Vibrators
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 00206649
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 1 1994 12:00AM