TM 5-809-3/NAVFAC DM-2.9/AFM 88-3, Chap. 3
(2) Disadvantages.
g.
Mechanical pulse velocity.
(a) Somewhat time consuming to
(1) Advantages.
(a) Reasonably simple to use.
prepare.
(b) Requires removal of two masonry
(b) Establishes uniformity of properties.
(c) Can detect flaws, cracks, and voids.
units.
(c) Restricted to masonry with low
(d) Possible to record trace of stress
cement-content mortar.
wave for later analysis.
(d) Requires unit replacement after the
(e) Equipment is readily available and
test.
only moderately expensive.
(e) Contribution of collar joint is
(f) Capable of testing over long
unknown.
distances in any type of masonry.
(f) Requires removal and replacement of
(g) Does not damage the masonry.
(2) Disadvantages.
two mortar joints.
(g) Large amount of equipment is
(a) Several pieces of equipment are in-
required.
volved, not easily portable.
f. Ultrasonic pulse velocity.
(b) Requires a separate instrument to
(1) Advantages.
record the wave arrival time.
(a) Simple to use.
(c) No direct correlation between results
(b) Establishes uniformity of properties.
and material properties.
(c) Can detect flaws, cracks, or voids.
(d) Analysis of the wave trace can be
d) Possible to record trace of stress
complicated.
h. Magnetic methods.
wave for analysis.
(e) Equipment readily available and only
(1) Advantages.
(a) Equipment is portable and
moderately expensive.
(f) Equipment package is self contained
inexpensive.
(b) Large areas of masonry can be
and portable.
(2) Disadvantages.
quickly evaluated.
(a) Requires access to both sides of a
(c) Accurately maps location and
wall for direct measurements.
orientation or reinforcing steel in masonry.
(d) Can be used to locate metal ties and
masonry restricts distance between transducers for
connectors.
(2) Disadvantages.
indirect and semi-direct use.
(c) Coupling material needed between
(a) Readings can be ambiguous,
masonry and transducers, which may alter the ap-
requiring operator interpretation or destructive
pearance of the masonry.
tests to verify conclusions.
(d) Grinding may be required to prepare
(b) Misidentification of metal conduit,
a rough surface.
etc., as reinforcing steel is possible.
(e) No direct correlation with material
(c) Accuracy in determination of bar size
properties.
and depth is questionable.
10-12
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