Abstract
The ultrasonic pulsating method is useful for inspecting the physical properties of mortar and concrete specimens.
In the first paper of this series, the authors estimated the change in properties regarding mortar and concrete specimens by using the characteristics of ultrasonic pulses propagated under uniaxial compressive loading.
Especially, the relation between the ultrasonic pulse velocity (Vp) and the progress of breakage (inelastic volumetric strain:Δεν) were discussed in detail.
The present paper deals with the attenuation of ultrasonic pulses propagated through mortar and concrete specimens, and the results are compared with those of another nondestructive testing experiment (A. E. method) and with the results obtained from the previous paper in this study.
The results obtained are as follows.
1) For the specimens undergoing deformation, the change in the amplitude ratio (A/A0) was affected much more than that of the velocity ratio (Vp/V0) with a change between the condition of ultimate stress and that of a complete breakdown.
2) In the same as the attenuation coefficients of the ultrasonic pulses propagated to a direction perpendicular to specimen's axis, the A. E. count rates increased with an increase in the inelastic volumetric strain (in the microfracturing zone).
3) In the comparison with the value of the propagation velocity within the cracking zone, it seems that the value of the attenuation coefficient, which was calculated from the propagation velocities and the amplitudes of the ultrasonic pulse, is a much more effective index for inspecting the mortar and concrete materials under uniaxial compressive loading.
