SYMPOSIA PAPER Published: 01 January 1999
STP14208S

New NDE Technologies for Evaluating Reinforced Concrete Masonry

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Researchers at the Waterways'Experiment Station (WES) have demonstrated that two new nondestructive evaluation technologies show promise in making a more accurate diagnosis of the structural condition of concrete masonry walls than prior technologies. Traditionally, sounding with a hammer has been used to determine the presence and quality of the grout fill around the reinforcing bars in concrete masonry units (CMU's). First, WES has developed a new grout detection system, which senses the reverberating energy in the CMU's with a microphone. This energy is introduced into the CMU by using a pistol to fire a metal BB against the face of the block. A microphone and spectrum analyzer replaces the function of the human ear to distinguish different pitches of sound through sounding. Since a technician is more likely to get consistent results with the new system, it is not as subjective as sounding. Next, WES has evaluated the new digital steel detectors. A reinforced concrete masonry structure can contain many combinations of steel: vertical bars, horizontal bars, size of bar, number of bars, splices, etc. Digital steel detectors with microprocessors have the potential to provide much more information than traditional analog types.

Author Information

Alexander, AM
Structures Laboratory, Waterways Experiment Station, Vicksburg, MS
Haskins, RW
Information Technology Laboratory, Waterways Experiment Station, Vicksburg, MS
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Details
Developed by Committee: C15
Pages: 148–161
DOI: 10.1520/STP14208S
ISBN-EB: 978-0-8031-5404-9
ISBN-13: 978-0-8031-2600-8