Civil Engineering Reference
In-Depth Information
FIGURE 7.35
Windsor probe test
device.
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7.5.6
Ultrasonic Pulse Velocity Test
The ultrasonic pulse velocity test (ASTM C597) measures the velocity of
an ultrasonic wave passing through the concrete (Figure 7.36). In this test,
the path length between transducers is divided by the travel time to de-
termine the average velocity of wave propagation. Attempts have been
made to correlate pulse velocity data with concrete strength parameters.
No good correlations were found, since the relationship between pulse ve-
locity and strength data is affected by a number of variables, such as age
of concrete, aggregate-cement ratio, aggregate type, moisture condition,
and location of reinforcement (Mehta and Moneiro 1993). This test is used
to detect cracks, discontinuities, or internal deterioration in the structure
of concrete.
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7.5.7
Maturity Test
Maturity of a concrete mixture is defined as the degree of cement hydra-
tion, which varies as a function of both time and temperature. Therefore,
it is assumed that, for a particular concrete mixture, strength is a function of
maturity. Maturity meters (Figure 7.37) have been developed to provide an
estimate of concrete strength by monitoring the temperature of concrete
with time. This test (ASTM C1074) is performed on fresh concrete and con-
tinued for several days. The maturity meter must be calibrated for each
concrete mix.
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