Table 4. Random variables that describe the concrete sulphate aggression process and their descriptions of probability distributions.

random variable [X]	Probability distribution	Var [X]	Min [X]	Max [X]
C0 (ion concentration at column trench)	beta symmetrical	0.15	10[%]	20[%]
λ (time of sulphate ions attack per year)	beta symmetrical	0.15	0[days/year]	12[days/year]