STP1356

    New NDE Technologies for Evaluating Reinforced Concrete Masonry

    Published: Jan 1999


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    Abstract

    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.

    Keywords:

    reinforced concrete masonry, nondestructive testing, steel detection, grout detection


    Author Information:

    Alexander, AM
    Research Physicist, Structures Laboratory, Waterways Experiment Station, Vicksburg, MS

    Haskins, RW
    Electrical Engineer, Information Technology Laboratory, Waterways Experiment Station, Vicksburg, MS


    Paper ID: STP14208S

    Committee/Subcommittee: C15.03

    DOI: 10.1520/STP14208S


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