TY - JOUR
T1 - Effect of natural carbonation on chloride binding behaviours in OPC paste investigated by a thermodynamic model
AU - Guo, Bingbing
AU - Qiao, Guofu
AU - Han, Peng
AU - Li, Zhenming
AU - Fu, Qiang
PY - 2022
Y1 - 2022
N2 - The combined effects of carbonation and chloride attack can accelerate the degradation of reinforced concrete (RC) structures. In this study, the effect of natural carbonation on the chloride binding behaviours in Ordinary Portland cement (OPC) paste was investigated. The phase-equilibrium model for the dissolution/precipitation reactions and the surface complexation model for the ionic adsorption of C–S–H were adopted. An experiment from the literature was used as the benchmark. The results indicate that Kuzel's salt is produced when OPC paste is exposed to a mild chloride attack. During the natural carbonation process, Kuzel's salt is converted into Friedel's salt. As the carbonation continues, the Friedel's salt disappears. Complete natural carbonation results in a total loss of chemical binding capacity, and only a partial loss of the physical binding capacity in cement-based materials. This completely differs from the accelerated carbonation commonly used in the laboratory, which can cause complete loss of both chemical and physical binding capacity. Therefore, the durability design of RC structures vulnerable to the combined attack of chloride and carbonation based on the results of the accelerated carbonation is conservative.
AB - The combined effects of carbonation and chloride attack can accelerate the degradation of reinforced concrete (RC) structures. In this study, the effect of natural carbonation on the chloride binding behaviours in Ordinary Portland cement (OPC) paste was investigated. The phase-equilibrium model for the dissolution/precipitation reactions and the surface complexation model for the ionic adsorption of C–S–H were adopted. An experiment from the literature was used as the benchmark. The results indicate that Kuzel's salt is produced when OPC paste is exposed to a mild chloride attack. During the natural carbonation process, Kuzel's salt is converted into Friedel's salt. As the carbonation continues, the Friedel's salt disappears. Complete natural carbonation results in a total loss of chemical binding capacity, and only a partial loss of the physical binding capacity in cement-based materials. This completely differs from the accelerated carbonation commonly used in the laboratory, which can cause complete loss of both chemical and physical binding capacity. Therefore, the durability design of RC structures vulnerable to the combined attack of chloride and carbonation based on the results of the accelerated carbonation is conservative.
KW - Carbonation
KW - Cement-based materials
KW - Chloride binding
KW - Thermodynamic modelling
UR - http://www.scopus.com/inward/record.url?scp=85122620793&partnerID=8YFLogxK
U2 - 10.1016/j.jobe.2022.104021
DO - 10.1016/j.jobe.2022.104021
M3 - Article
AN - SCOPUS:85122620793
SN - 2352-7102
VL - 49
JO - Journal of Building Engineering
JF - Journal of Building Engineering
M1 - 104021
ER -