Material or geometrical property changes in the concrete results in failure of concrete structures. The detection of uncontrolled
failure primers in the early stages can prevent or eliminate catastrophic damage. Visual inspection and destructive
testing are not always feasible for assessing internal crack initiation and propagation in in-service structures. We present our
work towards the development of embedded nano scale geometries which a capable of being used in concrete structures as a
self-sensing diagnostic tool that can detect and communicate the initiation of cracks which may lead to failure of the structure,
rendering a pre-emptive structural health monitoring tool. This paper will present data to support the hypothesis that
single-walled carbon nanotubes (SWNTs) can in fact be a benign inclusion, capable of active sensing, when incorporated into
cement based composites for the purpose of detecting crack initiation. As such we investigate the use of homogeneous length
sorted SWNTs that are randomly distributed in percolated networks capable of being an internal responsive net mechanism.
Our findings demonstrate increased microstructure sensitivity of our networks for our shorter length nanotubes near their
critical percolation threshold. This shows promise for the development of even more sensitive, embedded piezoresistive
SWNT-based sensors for pre-emptive failure detection technology.
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