Mechanical and Electrical Properties of Carbon-NanoFiber Self-Consolidating Concrete

Concrete is the most widely used construction material, and carbon nano-fiber (CNF) has many advantages in both mechanical and electrical properties such as high strength, high Young's modulus and high conductivity. These characteristics enable the nanofibers to bridge microcracks inside the concrete and absorb the energy normally released during crack propagation. Due to large Van der Waals forces between carbon nano-fibers, however, uniform dispersion of the carbon nanofibers throughout the cement matrix is difficult to achieve. In order to improve the dispersal of CNF, Self-Consolidating Concrete (SCC) was used to increase flowability throughout the wet concrete. In this paper, the mechanical and electrical properties of self-consolidating concrete containing carbon nano-fiber with different concentration were experimentally studied by conducting compression test, split tensile test and four point bending test. The test results indicate that the compressive strength of concrete containing CNF is greater than those of plain concrete and the change of electrical resistance is also more sensitive than those of plain concrete under both compression and tension stresses resulting from bending that are the most basic action in reinforced concrete structures. Therefore, a reasonable concentration of CNF was obtained for use in SCC which not only enhances mechanical performance, but also improves the electrical properties required for strain monitoring, damage evaluation, and self health monitoring of concrete and make concrete itself to be a smart material.