Nondestructive Evaluation of Damage in Concrete Under Uniaxial Compression

Abstract

Nondestructive evaluation of a transversely isotropic cylinder encased in a solid elastic medium AIP Conf.ABSTRACT. Surface wave velocities over the sonic frequency range (< 20 KHz) were measured on concrete specimens undergoing various cycles of loading and unloading. Acoustic Emission test (AE) was conducted simultaneously to monitor the microcracking activities. The sonic surface wave velocity was found to be highly stress-dependent. The observed changes in surface wavespeed are repeatable and follow a particular trend. By measuring the wave velocities in both loading and unloading phases, the effects of stress and stress-induced damages could be distinguished. The observed trend could be explained by a combination of acoustoelasticity and microcracking theories.

Non destructive testing of concrete nuclear containment plants with surface waves: Lab experiment on decimeter slabs and on the VeRCoRs mock-up

“…First we can notice that the two measurements on face B are superimposed showing the reproducibility of the experimental set-up but also the robustness of the surface wave measurement protocol consisting in averaging 50 random positions of MACSYS probe seismograms. Similar precision, at low stress level, has been observed before in the literature [5] but with lower frequencies and with sensors glued on the concrete that are not removed from the concrete during all the tests. With our protocol and the dry coupling transducers, the surface wave phase velocity is measured with a precision better than ±5 m/s.…”

Nonlinear elasticity in rocks: A comprehensive three-dimensional description

“…They consider the particular case of a high-frequency (HF) pulse of relatively small amplitude (probe) used to probe the local change of elastic wave speed induced by a large deformation (pump). This configuration has been widely adopted for the measurement of TOECs [30,31] or to investigate the effects of stress on wave speed [32][33][34]. Murnaghan's theory does not predict hysteresis or slow dynamics in the stress-strain relation.…”

Development of a Nondestructive Impulse Device and Damage Model for Unreinforced Concrete

“…A more recent study [16] indicates that the elastic properties of the material are dependent not only on the growth of microcracks but also on the closing of microcracks. Some researcheres [16] have shown in a feasibility study that surface wave velocities propagating parallel to the direction of loading demonstrate a distinct stress sensitive behavior. During this study, surface wave velocities were measured while concrete specimens were uniaxially loaded to 35% and 80% of the ultimate compressive strength.…”

“…There is also an anisotropic behavior of elastic waves in loaded concrete specimens that depends on the direction of loading relative to the direction of wave propagation [16]. Thus, the presence of microcracks forming in the same direction of loading can be measured by determining the changes in stress wave propagation in that direction.…”