Bending fracture of textile reinforced cement laminates monitored by acoustic emission: influence of aspect ratio

Textile reinforced cement based composites (TRC) are a new class of sustainable construction materials
with superior tensile strength and ductility. These materials have the potential for becoming load bearing
structural members, therefore a wide array of structural and non-structural applications are possible.
However, their heterogeneous, laminated, ?brous nature complicates the understanding of their fracture
behavior. During bending, the developed stresses lead to the activation of damage mechanisms like
matrix cracking, ?ber pull-out delamination and in succession or in overlap. In this study, the ?exural
behavior of TRC laminates is monitored by acoustic emission (AE). AE sensors record the elastic waves
radiated from the damage sources and enable the characterization of the fracture behavior in any stage.
The aim is to examine if AE is sensitive enough to provide feedback on the applied stress ?eld in such
heterogeneous systems. Therefore, the three-point bending span is varied to modify the stress ?eld
and speci?cally the proportion of shear to normal stress. AE waveform parameters like duration and frequency
reveal information about the mode of fracture for the different spans, while the stress ?eld is
derived by a ?nite element model (FEM). The results show that AE is suitable to characterize the stress
?eld even from the early loading stages, monitor the corresponding damage mechanisms and provide
valuable feedback to the material modeling.

Publication year:2014

Keywords:inorganic phosphate cement, IPC, textile reinforced cement composites, bending, fracture mode, interlaminar shear, frequency, monitoring, acoustic emission

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