TY - JOUR
T1 - Assessment of the protective effect of carbonation on portlandite crystals
AU - Galan, Isabel
AU - Glasser, F. P.
AU - Baza, D.
AU - Andrade, C.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - The kinetics of many reactions important to cement hydration and use are not well understood: this is in part due to the great complexity of many supposedly "simple" processes. One such process, carbonation of portlandite, Ca(OH)2, in moist air at ~ 23 °C has been investigated by microscopy and microchemical analysis. Single crystals of portlandite were grown, carbonated at relative humidities between ~ 25 and ~ 90%, and the transport properties of the self-generated calcite, CaCO3, product film were determined. The calcite films thus grown within days or weeks varied in thickness but typically were polycrystalline and epitaxial: a variety of morphologies and surface features are recorded. Permeation was measured by determining the time taken for Ca2 + ions, arising from the Ca(OH)2 substrate, to diffuse through the calcite coat into initially pure water. The spontaneous formation of self-protecting films on concrete has long been envisaged: results demonstrate that passivation can actually be achieved.
AB - The kinetics of many reactions important to cement hydration and use are not well understood: this is in part due to the great complexity of many supposedly "simple" processes. One such process, carbonation of portlandite, Ca(OH)2, in moist air at ~ 23 °C has been investigated by microscopy and microchemical analysis. Single crystals of portlandite were grown, carbonated at relative humidities between ~ 25 and ~ 90%, and the transport properties of the self-generated calcite, CaCO3, product film were determined. The calcite films thus grown within days or weeks varied in thickness but typically were polycrystalline and epitaxial: a variety of morphologies and surface features are recorded. Permeation was measured by determining the time taken for Ca2 + ions, arising from the Ca(OH)2 substrate, to diffuse through the calcite coat into initially pure water. The spontaneous formation of self-protecting films on concrete has long been envisaged: results demonstrate that passivation can actually be achieved.
KW - B surface layer
KW - C carbonation
KW - C durability
KW - C permeability
KW - D Ca(OH)<inf>2</inf>
UR - http://www.scopus.com/inward/record.url?scp=84921972008&partnerID=8YFLogxK
U2 - 10.1016/j.cemconres.2015.04.001
DO - 10.1016/j.cemconres.2015.04.001
M3 - Article
AN - SCOPUS:84921972008
SN - 0008-8846
VL - 74
SP - 68
EP - 77
JO - Cement and Concrete Research
JF - Cement and Concrete Research
ER -