Publisher's Synopsis
Smart cement is a chemo-thermo-piezoresistive material that functions as a highly sensing 3-dimensional (3D) bulk sensor. It can be used for monitoring changes in concrete and give warning before structural failure. This is achieved by adding a very small proportion (0.03%) of selected conductive or semi-conductive fibers to the bulk cement. Electrical resistivity, a second order tensor, serves as the monitoring parameter, alongside impedance-frequency characterization. It does not make the cement conductive or change its rheological properties, nor does it rely on buried sensors or nano particles. The change in electrical resistivity is always positive under both tension and compressive loading (stress or strain) since the shear stress and strain induced in the smart cement material makes the electrical resistivity increase, by an amount dependent on the type of applied stresses and strains. This is over 500 times higher than the strain, making the cement a highly sensing material. Smart cement can be used in grouts and repair materials and as smart foam cement. It can detect contamination, temperature, gas leaks and pre-seismic (dynamic) activities. Performance with selected additives such as nano materials and with inorganic and organic polymers has also been characterized.
