Preparation and piezoresistive properties of carbon fiber-reinforced alkali-activated fly ash/slag mortar

Self-Sensing Alkali-Activated Materials: A Review

“…where σ = applied stress. The strain response may differ between loading cycles due to repeatability issues resulting from microcracks and deformations in the matrix [134] or due to polarization effects [53]. Table 3 below displays the reported strain sensing performances and GFs of AAM.…”

“…Under strain tests, the response is dominated by conduction within the filler, and the change of the conductive network inside the matrix. In situations in which the applied load generates cracks in the sample, the resistance is expected to abruptly increase due to the destruction of the conductive network [51][52][53]58].…”

“…The types of conductive filler that have been used in AAM strain sensing include carbon fibre [25,53,110], graphene [24,55], graphite powder [52], carbon nanotubes [23,58] and carbon black [51]:…”

“…With respect to carbon fibre, the change in resistance has been attributed to the reduction in the conduction length due to physical shortening of the compression surface [110], and the change of the proximity between fibres [53].…”

“…While AAM have been effectively used in sensing applications without conductive filler, situations exist in which filler free samples did not present similar performance. In particular, cases have been reported where AAM failed to showcase any sensing response [53] and in which AAM have been rendered unsuitable for certain types of applications due to repeatability and reversibility issues [51]. As a result, conductive filler was required in both cases to allow for more reliable sensing performances.…”