TY - GEN
T1 - Characterization of distributed damage in concrete using advanced impact-echo method
AU - Livingston, R. A.
AU - Sutin, A. M.
AU - McMorris, N.
AU - Ceary, M.
AU - Amde, A. M.
PY - 2005
Y1 - 2005
N2 - The extent of damage caused by delayed ettringite formation has not yet been established. A field study of damaged bridges has been initiated in the state of Maryland involving both destructive and nondestructive test methods. To characterize the physical damage in the form of distributed microcracking, a modified version of the impact echo test was used. This used the attenuation of the echoes as the parameter to quantify the damage rather than the pulse velocity. The successive peaks in the waveforms were fitted to an exponential decay model and Q factor was calculated. The Q factor was then used as the damage variable. Surveys were carried out on 12 concrete bridges across the state of Maryland. On apparently undamaged concrete, it was possible to obtain reasonably good fits to the data. The Q factor was typically higher than 15 which is consistent with negligible microcracking. However, waveforms taken on damaged concrete often were too distorted to permit a good fit using a simple high pass filtering method. Preliminary work using more advanced signal processing methods suggests that it is possible to extract the parameters even in damaged areas by using data windowing to eliminate the early transients, band pass filtering around the resonant frequency and using both positive and negative peak amplitudes. The preliminary measurements show decreasing of Q factor due to crack presence.
AB - The extent of damage caused by delayed ettringite formation has not yet been established. A field study of damaged bridges has been initiated in the state of Maryland involving both destructive and nondestructive test methods. To characterize the physical damage in the form of distributed microcracking, a modified version of the impact echo test was used. This used the attenuation of the echoes as the parameter to quantify the damage rather than the pulse velocity. The successive peaks in the waveforms were fitted to an exponential decay model and Q factor was calculated. The Q factor was then used as the damage variable. Surveys were carried out on 12 concrete bridges across the state of Maryland. On apparently undamaged concrete, it was possible to obtain reasonably good fits to the data. The Q factor was typically higher than 15 which is consistent with negligible microcracking. However, waveforms taken on damaged concrete often were too distorted to permit a good fit using a simple high pass filtering method. Preliminary work using more advanced signal processing methods suggests that it is possible to extract the parameters even in damaged areas by using data windowing to eliminate the early transients, band pass filtering around the resonant frequency and using both positive and negative peak amplitudes. The preliminary measurements show decreasing of Q factor due to crack presence.
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M3 - Conference contribution
AN - SCOPUS:84869825689
SN - 9781617820632
T3 - 11th International Conference on Fracture 2005, ICF11
SP - 2304
EP - 2309
BT - 11th International Conference on Fracture 2005, ICF11
T2 - 11th International Conference on Fracture 2005, ICF11
Y2 - 20 March 2005 through 25 March 2005
ER -