Piezoresistive cement-based materials for strain sensing

Cement-based materials that exhibit piezoresistivity with sufficient magnitude and reversibility contain electrically conductive fibers. The phenomenon allows the materials to sense their own strain. The fibers are preferably discontinuous. Carbon fibers (15 mum diameter) are most effective. Steel fibers (8 mum diameter) are less effective. Carbon filaments (0.1 mum diameter) are ineffective. The piezoresistive behavior, mechanism and materials are reviewed, including cement-based materials with continuous and discontinuous fibers.