Mechanical and smart properties of carbon fiber and graphite conductive concrete for internal damage monitoring of structure

•The research provides a pathway to significantly improving the mechanical and smart property of concrete.•Micro-characterization was used to quantify the effects of carbon fibers and graphite on the microstructure of paste.•Smart property under flexure of concrete added with carbon materials was investigated.•Optimum performance of concrete was achieved by an addition of 0.7 wt% CF and 2.5 wt% G.•Strain dependent resistivity characteristic was well drawn by quadratic polynomial.

The piezoresistivity and smart property under flexure in concrete for water-binder ratio of 0.38 were investigated by adding well-dispersed carbon fibers and graphite to improve its mechanical and smart performance. Thence, the reveal of the smart property under flexure was demonstrated from the experiment by three-point loading as well as the relationship between the strain and variance ratio of resistance was in discussion. The result shows successful in cement mixing by carbon fibers and graphite in 0.7 wt% and 2.5 wt% in mechanical and smart performance which implies that carbon fibers are capable partially replaced by graphite. In addition, the strain dependent resistivity characteristic was able to drawn by quadratic polynomial while the microtopography of the composite material was uncovered by the scanning electron microscopy (SEM).