Hybrid NDE for rebar corrosion in reinforced concrete

Title: Hybrid NDE for rebar corrosion in reinforced concrete
Author(s): Masayasu Ohtsu, Yuma Kawasaki, Misuzu Kitaura and Yuichi Tomoda
Paper category : conference
Book title: International RILEM Conference on Advances in Construction Materials Through Science and Engineering
Editor(s): Christopher Leung and K.T. WAN
ISBN: 978-2-35158-116-2
e-ISBN: 978-2-35158-117-9
Publisher: RILEM Publications SARL
Publication year: 2011
Pages: 364 - 370
Total Pages: 7
Nb references: 6
Language: English

Abstract: To maintain concrete structures in safe and healthy conditions, nondestructive evaluation (NDE) for corrosion damage is recently in critical demand. Conventionally, NDE for corrosion of reinforcing-steel bars (rebars) has been performed by electro-chemical techniques of half-cell potential and polarization resistance. Although these could be useful for estimation of rebar corrosion, results measured are marginally successful because of uncertainty, depending on many factors associated with the measuring conditions.
A great promise is realized for an applicability of acoustic emission (AE) techniques to monitoring the rebar corrosion. High AE activities are observed twice during the corrosion process, corresponding to the onset of corrosion (1st stage) and the nucleation of corrosion cracking (2nd stage). It is reported that AE location analysis and SiGMA analysis provide visual information of damaged areas inside concrete in the 2nd stage.
In the present paper, practical NDE for the rebar corrosion in concrete structures is studied for developing a reliable early-warning system. Continuous AE monitoring was performed, combing with the electro-chemical techniques. Thus, a hybrid NDE is proposed. The 1st stage is readily identified from the decrease in the polarization resistance with the 1st high AE activity. The 2nd stage is determined from the 2nd high AE activity, keeping the half-cell potentials more negative than -350 mV (C. S. E.) and decreasing in Ib-values of AE amplitude distribution.

Online publication: 2011-10-31
Publication type : full_text
Public price (Euros): 0.00