Smart self-sensing concrete: the use of multiscale carbon fillers

In this study, the electrical and piezoresistive properties of cement-based composites with binary conductive fillers consisting of carbon nanofibers (CNFs) and recycled milled carbon fibers (rMCFs) were experimentally investigated. The self-sensing capability of these composites under quasi-static and cyclic compression loads was studied. Experimental results showed that the optimal self-sensing formulation contained CNFs 1 wt% and 0.5 wt% rMCFs. Strain and temperature fiber Bragg grating sensors were embedded inside specimens to verify the load test methodology. The novelty of this work lies not only in the sustainable use of recycled carbon fibers and partial replacement of CNFs in the formulation but also in lowering the cost of production of smart cementitious products for the structural health monitoring purposes by at least $1.99/g.