Detection of early-age cracking using acoustic emission

Title: Detection of early-age cracking using acoustic emission
Author(s): Stephan Pirskawetz, Frank Weise
Paper category : conference
Book title: International RILEM Conference on Volume Changes of Hardening Concrete: Testing and Mitigation
Editor(s): O. M. Jensen, P. Lura, K. Kovler
Print-ISBN: 2-35158-004-4
e-ISBN: 2351580052
Publisher: RILEM Publications SARL
Publication year: 2006
Pages: 385 - 392
Total Pages: 8
Nb references: 10
Language: English

Abstract: Acoustic emission (AE) was used to observe cracking processes in hardening silica fume cement paste and mortar with low water/binder ratio due to early-age autogenous shrinkage and thermal dilation. Comparative AE measurements were performed on specimens with and without external restraint of deformation. Simultaneously the unrestrained deformation was registered. The preliminary results presented in this paper showed that intense autogenous shrinkage occurred during the acceleration period of hydration. In both cement paste and mortar this was associated with the beginning of micro cracking shortly after setting irrespective of the existence of external restraint. The micro cracking was clearly more pronounced in the case of external restraint of deformation. The addition of aggregates reduced the deformations and altered the early-age cracking significantly. Less acoustic events with lower energies were registered in the mortar. It was found that in the first two days of hardening the cracking occurred mainly due to the internal restraint by the aggregates.

Online publication: 2006-07-30
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2351580052.041