Asphalt Rubber Technology Information Center
Dynamic Analysis of Asphaltic-Aggregate Mixtures
Document available through TRB
Stephenson, Richard W., Univ. of Missouri, Rolla  
Key Words:

Ultrasonic probes have been constructed for use in dynamic nondestructive testing of asphaltic concrete specimens.  
Use of the probe systems was superior to use of their main components alone, the piezoelectric crystals.  The probes
have the advantages of reducing ringing time, concentrating ultrasound in one direction, elimination of noise due to
unshielded connections, and increased durability.  The probes were used in a limited testing program.  Compression and
transverse wave velocities in the specimens tested were measured simultaneously.  Sample conditions suitable for
maximum strength and minimum voids in the mineral aggregate.  A relationship of increasing wave velocity with
increasing strength was noted.  Wave velocity was observed to increase as the percentage of voids in mineral aggregate
decreased.  Various elastic constants were calculated from the wave velocities measured.  Maximum values of E and G
moduli as well as Poisson's ratio corresponded to minimum voids of the test specimens.  Relative attenuation
measurements were conducted by using waster as a standard material.  An evaluation of relative attenuation with
changes in asphalt content indicated maximum damping at asphalt contents associated with high stability values.
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