A new smart sustainable earth-cement composite doped by carbon microfibers with self-sensing properties

Civil constructions need to be monitored during their lifespan to assess any changes in structural performance following critical events. Among the various available monitoring solutions, this paper contributes to the literature on multifunctional construction materials that have the ability to provide an electrical output that can be correlated with materials' damage. The novelty of the work consists of achieving self-sensing properties in a sustainable concrete, where cement is substituted with natural earth in the ratio of 7/2 in volume. Self-sensing properties are provided through the addition of a small amount of carbon microfibers enabling a piezoresistive behavior. Experimental tests were carried out using samples with different shapes to investigate their electrical and sensing properties. The results showed that the best carbon microfiber doping level of 0.05% relative to the binder exhibited clear and repeatable signals, an average gauge factor of 46, and high linearity. Moreover, the smart multifunctional earth-concrete showed good electrical, diagnostic, and sensing properties during failure tests.