Cracking Mechanism of Corroded Reinforced Concrete Column Based on Acoustic Emission Technique

The Acoustic Emission (AE) technique is applied to study the failure mode, damage evolution process, and cracking mechanism of reinforced concrete (RC) columns under the coupling effect of exterior compression load and interior reinforcement corrosion. AE signals are collected from different loading stages for corroded and uncorroded RC column specimens. Parameter analyses are conducted to analyze the peak frequency, energy distribution, and phase parameters used to achieve the general changing conditions of AE signals. Fast Fourier Transform is applied to reveal the time-variant rules of signal frequency and energy in different damage stages. Discrete Wavelet Transform is used for a better understanding of the local time-frequency properties of the non-stationary AE signals and optimally interprets the damage evolution process of the RC structure. Results show that the peak frequency has a 3-layered distribution; an obvious double-peak trend of the energy distribution indicates two cracking mechanisms: steel/concrete interface damage and aggregate/cement damage. The damage process consists of four stages: micro-crack formation, micro-crack development, crack expansion, and cracking failure. The corrosion behavior remarkably influences the energy distributions of the two cracking mechanisms, the characteristics of the spectra in different stages, and the damage evolution process inside the RC columns.

Automated summary

The study applies the Acoustic Emission (AE) technique to investigate the failure mode, damage evolution process, and cracking mechanism of reinforced concrete (RC) columns under the influence of external compression load and internal reinforcement corrosion. AE signals are collected from corroded and uncorroded RC column specimens at different loading stages, and parameter analyses are conducted to analyze the changing conditions of AE signals. Results reveal the time-variant rules of signal frequency and energy and provide insights into the damage evolution process of the RC structure. The corrosion behavior significantly affects the energy distributions, spectral characteristics, and damage evolution process of the RC columns.