Non-destructive evaluation of carbon nanofibre concrete

Concrete is the most widely manufactured construction material. The addition of carbon nanofibres (CNFs) to concrete has many advantages in terms of mechanical and electrical properties (e.g. higher strength, higher Young's modulus and improved fatigue resistance) and self-monitoring behaviour due to the high tensile strength and high conductivity. In this work, the pulse velocity method was used to characterise the properties of concrete containing CNFs. Concrete strength correlations between pulse velocity, electrical resistance variation and destructive tests were analysed for different mix proportions. The test results indicate that the compressive strength, pulse velocity and percentage reduction in electrical resistance while loading concrete containing CNF differ from those of plain concrete. Based on the pulse velocity results, a reasonable concentration of CNFs was determined for use in concrete, which not only enhances compressive strength, but also improves the electrical properties required for strain monitoring, damage evaluation and self-health monitoring of concrete.