Research Article
Concrete Mix Design for Service Life of RC Structures under Carbonation Using Genetic Algorithm
Table 1
Influencing parameter on carbonation behavior.
| Internal parameter (mixture) | Low w/c and large unit cement amount | (i) Holding pH in alkali through producing large amount of hydration of CSH and Ca(OH)2 (ii) Low CO2 diffusion through dense pore structure | Aggregate | CO2 intrusion through artificial light weight aggregate | Mineral admixture (slag and fly ash) | (i) Small amount of Ca(OH)2 due to pozzolanic reaction and latent hydraulic reaction | (ii) Low diffusion coefficient of CO2 | Mixed chloride content | Rapid carbonic reaction due to high pH from ion dissociation |
Alkali | (i) Rapid carbonic reaction due to high alkali cement | (ii) Residual metallic oxide (K2O, Na2O) |
| External parameter | CO2 concentration | Rapid carbonation through higher concentration of CO2 | Temp. | Increasing activity energy due to high temperature (Arrhenius law) |
R.H. | (i) Decreasing carbonation in low R.H. due to insufficient H2O | (ii) Decreasing carbonation in high R.H. due to low CO2 diffusion | Induced chloride ion | Rapid carbonation due to dissociated chloride ion (cation) |
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