Physical and chemical effects of isopropanol exchange in cement-based materials

Abstract Drying cement-based materials is a necessary step to characterize the microstructure by microscopy, adsorption, or mercury intrusion. The isopropanol (IPA) exchange method commonly used replace pore solution prior drying, as it reduces capillary pressure and thereby helps preserve of hydrated cementitious materials. However, some physical chemical effects IPA on hydration products have been reported. These cannot be completely avoided, but can reduced shortening duration, in particular for ettringite. This study carried out experiments with different durations removal techniques address research gaps literature. For 1-mm cubes cement paste diffusion coefficient 1 × 10?11 m2/s, compared are 5 min, 15 min (value from literature), 40 min (when mixture at sample center achieves 95% drop surface tension water IPA), 80 min IPA/water reaches an azeotrope), 5 h over 99% replaced center), 24 h (prolonged exchange). After exchange, samples were either directly dried 40 °C flushing N2 washed diethyl ether drying. Even though duration 40 80 min, theory, reduce damage pressure, nitrogen adsorption results do not show any advantage preventing microstructural alteration. 5-h provided similar 24-h latter induced slightly more serious resulting longer contact products. In addition, significant differences. Therefore, this suggests using small (~1 mm) studies following period corresponding time when (mole fraction) replaced.