Concrete Mix Design for Service Life of RC Structures under Carbonation Using Genetic Algorithm

Table 2

Semiempirical equations for carbonation process.

Researcher	Equations
Syrayama	𝑡=𝛼𝛽𝛾𝛿𝜀5000𝐶^2(𝑥−38)^2
	𝐶: carbonation depth, 𝑥: w/c ratio
	𝛼,𝛽,𝛾,𝛿,𝜀: factors for admixtures, cement type, exposure condition, and so forth
Kishitani	𝑡=0.3(1.15+3w/c)𝐶^2𝑅^2(w/c−0.25)^2 (w/c ≥ 0.6)
	𝑡=7.2𝐶^2𝑅^2(4.6w/c−1.76)^2 (w/c < 0.6)
	𝐶: carbonation depth
	𝑅: factor for cement type, aggregate type, and surface treatment
Hamada	𝑡=𝑘𝐶^2𝑅, 𝑘=0.3(1.15+3𝑥)(𝑥−0.25)^2
	𝐶: carbonation depth, 𝑥: w/c ratio
	𝑅: factor for cement type, aggregate type, and surface treatment
Ida	𝑡=𝛼𝛽𝛾𝐾𝐶^2(100𝑥−18)^2
	𝐶: carbonation depth, 𝑥: w/c ratio
	𝐾: factor for exposure and cement type
	𝛼,𝛽,𝛾: quality, retardation, and environmental condition