A methodology for crack monitoring in structural concrete by combined digital image correlation and acoustic emission

Student thesis: Doctoral Thesis


Concrete is a widely used construction material characterized by low
capacity for deformation when subjected to tensile stresses. Concrete is
thus, susceptible to cracking; a phenomenon that can significantly affect its
structural integrity. The initiation and development of concrete cracks
involves a complex mechanism due to its heterogeneous nature. Crack
monitoring methods have been consequently developed in order to
characterize concrete cracks, results of which, should lead to insights for
proper (re)design of concrete elements thus ensuring minimal or
acceptable crack level. However, most of the existing stand-alone crack
monitoring techniques have some limitations in characterizing concrete
This doctoral research work focused on a methodology of combined use of
digital image correlation (DIC) and acoustic emission (AE) techniques for a
more effective monitoring of cracks in concrete structures at laboratory
standard tests level. The combined methodology provides complimentary
information from "the eye" aided by the DIC and from "the ear" aided by
the AE. Specifically, the focus was on data analysis and interpretation from
the experiments conducted on various structural concrete beams. It is
demonstrated that the combination of these two techniques has the
potential to lead to more quantitative and comprehensive results
compared to the stand-alone use of each method.
On practical application, this research work examined the behaviour of
railway prestressed concrete sleepers (PCS) based on the Belgian
homologation procedure. The quasi-static tests were conducted as starting
point towards updating the homologation procedure for PCS based on
combined methodology of DIC and AE techniques. On one hand, the DIC
offers a fast and reliable alternative crack monitoring technique to
traditional graduated microscopes while on the other hand, combined
methodology offers more insights to cracking mechanisms which is crucial
in understanding reasons for non-conforming PCS.
In a complimentary and easy-to-understand manner, it is demonstrated
that combined DIC and AE methodology can improve the understanding of
concrete cracking behaviour and enhance practical applications.
Date of Award20 Apr 2015
Original languageEnglish
Awarding Institution
  • Vrije Universiteit Brussel
SupervisorDimitrios Angelis (Jury)

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