Acoustic emission behavior of steel fibre reinforced concrete under bending

Abstract

The present paper describes the Acoustic Emission (AE) behavior of concrete under four-point bending. Steel fibres of varying content were used as reinforcement in concrete slabs and their influence on the fracture process and the acoustic activity was investigated. The total acoustic emission (AE) activity was found to be directly proportional to the fibre content. Analysis revealed that particular AE parameters change monotonically with the progress of damage and can be used for the characterization of the failure process.

Damage Assessment in Fibrous Composites Using Acoustic Emission

“…RA value exhibits an explosive increase when fiber pull-out events result after extensive matrix cracking (Soulioti et al 2009, Aggelis et al 2011a. The same trend has been seen in concrete containing polymer fibers, as studied by the inverse of RA, namely "grade" of the waveform ).…”

“…2 . This has been shown in a number of studies concerning different kinds of materials like rock (Shiotani 2006), concrete (Ohno and Ohtsu 2010, Soulioti et al 2009, Aggelis et al 2011a, metals (Aggelis et al 2011b) and composite laminates (Aggelis et al 2010b). It originates from the different elastic wave modes (longitudinal and shear) that are emitted from the mode I excitation (opposing movement of the crack faces) and mode II (sliding movement) respectively (Aggelis et al 2010c).…”

“…A parameter that has extensively been used for characterization of the fracture mode mostly depends on the shape of the initial part of the waveform. The ratio of A over RT, which is the "rise angle" or "grade" Philippidis 1995, Philippidis et al 1998) of the waveform, is recently utilized in the form of RA value , Ohtsu and Tomoda 2008, Soulioti et al 2009, Aggelis et al 2011a. This value is precisely the inverse of grade (rise time over the Amplitude measured in μs/V) (Ohno and Ohtsu 2010).…”

Detection of Microcracking in Concrete Subjected to Elevated Temperature at Very Early Age by Acoustic Emission

“…shifting from flexural cracking to shear/bond cracking, along with an increase in duration and amplitude. In other words, shear events were characterized by a longer rise time and usually higher amplitude than tensile events (Soulioti et al 2009), while average frequency tended to be higher for tensile cracking mode. A comparison of characteristics of AE obtained during direct tension test and during heat curing of the same mix concrete is presented in Fig.…”

Modelling and Assessment of Repairs Conducted on Composite Materials

“…Acoustic emission (AE) defined by ASTM E1316-05 [10] as "The class of phenomena whereby transient elastic waves are generated by the rapid release of energy from a localized source or sources within a material". The main aim of AE application for this research is to determine experimentally a characteristic set (fingerprints) of AE features that can potentially describe the size of circular pocket damage in composite and aluminium plate which has been correlated to finite element models.…”