State of the Art on Sensing Capability of Poorly or Nonconductive Matrixes with a Special Focus on Portland Cement–Based Materials

Concrete, a well-established and well-characterized building material, is also the most used building material in the world. However, many old and new-build structures suffer from premature failures due to extensive deterioration and decreased load-bearing capacity. Consequently, structural monitoring systems are essential to ensure safe usage of concrete structures within and beyond their designed life. Traditional monitoring systems are based on metallic sensors installed in crucial locations throughout the structure. Unfortunately, most of them have relatively low reliability and a very short life span when exposed to often very harsh environments. The ideal solution is therefore to develop a smart concrete having self-sensing capability. A number of studies have shown that conductive cementitious matrixes will undergo changes in their electrical resistivity with variations of stresses and strains or development of microcracking. This behavior can be used as a reliable tool to measure changes. This review provides a comprehensive overview of several nonconductive matrixes, with a special focus on portland cement–based materials, showing self-sensing capabilities by description of detection mechanisms, sensing capabilities, limitations, and potential applications.