Experimental studies and thermodynamic modeling of the carbonation of Portland cement, metakaolin and limestone mortars

TY - JOUR

T1 - Experimental studies and thermodynamic modeling of the carbonation of Portland cement, metakaolin and limestone mortars

AU - Shi, Zhenguo

AU - Lothenbach, Barbara

AU - Geiker, Mette Rica

AU - Kaufmann, Josef

AU - Leemann, Andreas

AU - Ferreiro, Sergio

AU - Skibsted, Jørgen

PY - 2016/10/1

Y1 - 2016/10/1

N2 - The carbonation of Portland cement, metakaolin and limestone mortars has been investigated after hydration for 91 days and exposure to 1% (v/v) CO2 at 20 °C/57% RH for 280 days. The carbonation depths have been measured by phenolphthalein whereas mercury intrusion porosimetry (MIP), TGA and thermodynamic modeling have been used to study pore structure, CO2 binding capacity and phase assemblages. The Portland cement has the highest resistance to carbonation due to its highest CO2 binding capacity. The limestone blend has higher CO2 binding capacity than the metakaolin blends, whereas the better carbonation resistance of the metakaolin blends is related to their finer pore structure and lower total porosity, since the finer pores favor capillary condensation. MIP shows a coarsening of the pore threshold upon carbonation for all mortars. Overall, the CO2 binding capacity, porosity and capillary condensation are found to be the decisive parameters governing the carbonation rate.

AB - The carbonation of Portland cement, metakaolin and limestone mortars has been investigated after hydration for 91 days and exposure to 1% (v/v) CO2 at 20 °C/57% RH for 280 days. The carbonation depths have been measured by phenolphthalein whereas mercury intrusion porosimetry (MIP), TGA and thermodynamic modeling have been used to study pore structure, CO2 binding capacity and phase assemblages. The Portland cement has the highest resistance to carbonation due to its highest CO2 binding capacity. The limestone blend has higher CO2 binding capacity than the metakaolin blends, whereas the better carbonation resistance of the metakaolin blends is related to their finer pore structure and lower total porosity, since the finer pores favor capillary condensation. MIP shows a coarsening of the pore threshold upon carbonation for all mortars. Overall, the CO2 binding capacity, porosity and capillary condensation are found to be the decisive parameters governing the carbonation rate.

KW - CaCO (D)

KW - Carbonation (C)

KW - Metakaolin (D)

KW - Portland cement (D)

KW - Thermodynamic calculations (B)

U2 - 10.1016/j.cemconres.2016.06.006

DO - 10.1016/j.cemconres.2016.06.006

M3 - Journal article

AN - SCOPUS:84975263550

SN - 0008-8846

VL - 88

SP - 60

EP - 72

JO - Cement and Concrete Research

JF - Cement and Concrete Research

ER -