Microstructure and pressure-sensitive properties of cement-based composite with Ni nanowires

Pressure-sensitive Ni nanowire/cement composites are fabricated using Ni nanowires as conductive filler. The Ni nanowires are obtained using an alternating current electro-deposition method by means of porous alumina template. Polycarboxylate superplasticizer as dispersing agent is applied. The microstructures, electrical resistivity and piezoresistivity of Ni nanowires/cement composites are examined. The results indicate that the Ni nanowires with the mean diameter of about 65nm and aspect ratio of 50 are well dispersed in the cement matrix. The surfaces of Ni nanowires are passivated with the oxide compound of Ni(OH)2 and NiO, influencing their electrical conductivity. The variation in the electrical resistivity of Ni nanowire/cement composite with the increase of Ni nanowire volume fraction displays a typical percolation phenomenon. In addition, the strain sensitivity coefficient of Ni nanowires/cement composite with 0.75 vol% Ni nanowires under uniaxial compression is 2354.6, far higher than those for the other pressure-sensitive cement-based composites.