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Innovation in Non-Destructive Seismic Testing
Applications 12/5/09
The civil engineer's dream is the black-box that can scan a road or structure, and report the time and the manner in which it will fail. We wish we knew how to build that black-box. Every measurement we know how to make, whether seismic, nuclear, or electromagnetic, gives only an indirect estimate of remaining life. Seismic-wave measurements are less indirect than others, and have several major strengths in realizing the ideal measurement.
The seismic modulus or stiffness is directly related to the square of velocity of stress-wave propagation.
Velocity/modulus reductions are measurable years before surface distress appears.
Life-cycle feedback
becomes possible. The same
physical property is measured in the lab
for material selection and design, in construction
test cylinders for material quality control, in-situ for construction quality control, and
in-situ over the lifetime of the
pavement for performance

High-frequency, low-strain measurements are linear, precise, and non-destructive, giving cost-effective laboratory characterization of aging, compaction, moisture, strain, and temperature dependence.
In-situ measures of construction quality are at stress and strain levels comparable to laboratory measurements.
The remediation effectiveness can be measured.