Tooru FUJITA

Influence of the Initial Defect in Concrete Cover on the Ingress of Aggressive Agents into Concrete

Supervisor Takumi SIMOMURA


In reinforced concrete member made with a concrete of large bleeding, porous concrete layer with high material permeability may be created around the reinforcing bar in concrete after hardening. In this research, the influence of this porous concrete layer on the ingress of aggressive agents into concrete and the corrosion of reinforcing bar ware investigated. The exposure test of reinforced concrete specimens were carried out under the condition simulating corrosive environment. Though the difference of corrosion reinforcing steel bar was not clear, the chloride concentration in concrete was surely affected by the initial defect in concrete due to bleeding. To verify this hypothesis, ink injection test was conducted. The ink injection was observed along the reinforcing bar in the specimen in which the casting direction of concrete had been perpendicular to the longitudinal direction of the reinforcing bar. Finally, the influence of the porous concrete layer on chloride ingress found in the experiment was verified through numerical analysis.