Self-Sensing Properties of Alkali-Activated Slag Composite with Carbon Black during Bending Test

Abstract

Aluminosilicate materials are generally considered electrical insulators. In order to achieve enhanced electrical conductivity these materials must doped with suitable conductive admixtures such as carbon black. These composites gain the importance in the new field of applications such as self-sensing materials or self-monitoring structures. This paper presents a study on self-sensing properties of alkali-activated slag composite with 2 and 4% of carbon black as conductive filler during repeated flexural and till fracture loading in the configuration of three-point bending test. The results showed that best performance of the self-sensing properties was achieved with 4% of carbon black, though both the compressive and flexural strengths were deteriorated.

Self-Sensing Alkali-Activated Materials: A Review

“…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]:…”

“…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.…”

“…For graphite powder and carbon black the changes in resistance have been attributed to changes in the conductive path the current follows in the matrix [51,52]. Chen et al [141] coated metakaolin AAM with a conductive polymer PEDOT:PSS solution.…”

“…Fractional change in resistivity of slag AAM under cyclic flexural loading, example adapted from[51].…”