The reinforcing steel in concrete corrodes due to various degradation factors. Since apparent volume of corroded reinforcement is larger than original one, expansive pressure is introduced. The mechanism of spalling of cover concrete and expansion of corrosion has mainly been studied in 2-dimensional sections. However, the 3-dimensional effect should be considered to make clear the spalling mechanism. In this paper, 3-dimensional finite element analysis that covers the 3-dimension effect is conducted. With considering coefficient of variation of maximum pressure in experimental tests, the corrosion length factor (Lemin/k) where the 3-dimensional effect can be ignored is proposed.
