Identification of corrosion mechanisms by univariate and multivariate statistical analysis during long term acoustic emission monitoring on a pre-stressed concrete beam

Acoustic Emission (AE) technique was used to monitor Hydrogen Assisted Stress Corrosion Cracking (HASCC) activated by using ammonium thiocyanate solution during a long term laboratory corrosion test on a pre-stressed concrete beam using post-tensioned steel strands. By univariate analysis, three stages of damage mechanisms were identified: activation, propagation and rupture. We therefore proposed a combination of principal component analysis and self organising maps algorithms as a new procedure to identify the progression of different damage mechanisms during time until final failure. Initiation, propagation and critical rupture phases were clearly identified and associated to specific features of the AE events.