TITLE:
Effects of Carbonation on the Microporosity and Macro Properties of Portland Cement Mortar CEM I
AUTHORS:
Son Tung Pham
KEYWORDS:
Carbonation, Cement Mortar, Microstructure, Nitrogen Adsorption, Intrinsic Gas Permeability, Thermal Conductivity, Thermal Diffusivity, Ultrasonic Velocities, Helium Pycnometry
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.2 No.7,
July
8,
2014
ABSTRACT: The aim of this work was to examine the
microstructural changes of CEM I standardised cement mortar caused by
accelerated carbonation (20% CO2 concentration) using porosity
accessible to water and nitrogen adsorption. The conflicted results obtained by
these two techniques showed the differences in porous domains explored, while
the pore size distributions calculated from nitrogen adsorption provided
evolution of the micro and meso pores during carbonation. The porosity
accessible to water showed changes in all three porous domains: macro, meso and
micro pores. This is because of difference in the molecular sizes between water
and nitrogen molecules. Although these two techniques are different, they help
to complementarily evaluate the effects of carbonation. The results also
indicated the influence of type of cement on microstructural evolutions and the
correlation between variations of mesopores volume and specific surface area.
Changes in microstructure induce changes in macroscopic properties that we also
examined such as the solid phase volume using helium pycnometry, the gas
permeability, the thermal conductivity, the thermal diffusivity, and the
longitudinal and transverse ultrasonic velocities.