A study on damage of steel fiber reinforced concrete (SFRC) under uniaxial compression based on the electrical resistivity method

This research aims at studying the relationship between the electrical resistivity and the damage of the SFRC during uniaxial compression. The electrical resistivity of concrete with four different volume fraction of steel fibers (0.0%, 1.0%, 1.5% and 2.0%) during uniaxial compression was tested. The effect of the number of steel fibers on the electrical resistivity of concrete was analyzed. Results showed that the addition of steel fibers reduces the initial electrical resistivity of concrete. When the volume fraction of steel fibers reached 1.5%, the conductive capacity of the concrete tended to reach its maximum, then the electrical resistivity decreased slowly and stabilized. During uniaxial compression, the electrical resistivity changing curves can be simplified as two modes, hook-shaped for plain concrete and "U"-shaped for SFRC. The relationship of the load and the electrical resistivity during uniaxial compression indicated that the electrical resistivity is determined by the combined effects of the micro-crack structure and the steel fibers. The change of the electrical resistivity of SFRC can reflect the evolution of concrete internal structure during loading.