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5. Acoustic emission in concrete of early-age



Title: 5. Acoustic emission in concrete of early-age
Author(s): M. Ohtsu
Paper category : book
Book title: Advanced Testing of Cement-Based Materials during Setting and Hardening - Final Report of RILEM TC 185-ATC
Editor(s): H.W. Reinhardt and C.U. Grosse
Print-ISBN: 2-912143-81-0
e-ISBN: 2912143705
Publisher: RILEM Publications SARL
Publication year: 2005
Pages: 255 - 275
Total Pages: 21
Nb references: 24
Language: English


Abstract: Concrete structures have their particular functions in service, which may deteriorate due to heavy traffic loads, fatigue, chemical reactions, unpredictable disasters, and poor workmanship. As a result, repair, retrofit and rehabilitation of the structures are eventually necessary, although the concrete structures have long been referred to as maintenance-free. It results in the need for the development of advanced and effective inspection techniques. Accordingly, acoustic emission (AE) techniques have been extensively studied in concrete engineering since early 80's [Ohtsu (1987)]. According to the literature, early studies were found on microcrack accumulation under unconfined compression [Rusch (1959), L'Hermite (1960)]. As can be seen in Fig. 1 [L'Hermite (1960)], AE activity is observed with the increase in the axial displacement over 75% of failure load (Ti), which is remarkably identical to the onset of the decrease in wave velocity and the increase in Poisson's ratio. These changes result from the volumetric expansion due to microcraking. Because AE phenomenon is directly associated with nucleation of cracks in concrete, the measurement in hardened concrete is readily applied to detect cracking activity.


Online publication: 2006-09-22
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143705.010