In Situ Experiments with Acoustic Emission and X-Ray Imaging to Measure Damage Processes in Concrete
摘要
Quantitative measurements of fracture and damage in cement-based materials has historically been a challenge due to complex and compounding phenomena occurring over a wide range of length and time scales. In the present work, two experimental techniques are combined in a single test: x-ray imaging, and acoustic emission monitoring. In x-ray imaging, the spatial resolution is high, but the temporal resolution is dependent on the image acquisition rate, and tends to be low. Conversely, in acoustic emission monitoring, the spatial resolution is limited, but the temporal resolution is extremely high. We find in combining the techniques in a configuration under which load and deformation are applied, we can exploit the strengths of the two techniques to not only better understand damage evolution, but to set the stage for more advanced techniques in which x-ray computed tomographic imaging, with its very high spatial resolution, can be triggered by acoustic emission signals. Preliminary tests show that acoustic emission signals can be matched to specific cracking phenomena in concrete, however the advancement of tomographic imaging is likely to provide the greatest potential for new insight.