WATER VAPOR ADSORPTION ISOTHERM MODEL OF PORTLAND CEMENT PASTE

Isotherm Equation for Water Vapor Adsorption onto Activated Carbon

A simple isotherm model has been developed for the type-5 equilibrium adsorption systems by considering the effects of both primary and secondary adsorptive sites. The model was applied to interpret experimental data describing water vapor adsorption capacities of four activated carbon adsorbents for relative vapor pressures from 0.0 to 0.95 and temperatures between 288 and 308 K. Good agreemen...

Drying Shrinkage Mechanisms in Portland Cement Paste

The shrinkage mechanisms of portland cement paste were investigated from shrinkage, weight loss, and pore structure measurements using nitrogen sorption and mercury intrusion porosimetry (MIP). Thin samples (2.3 mm) of well-hydrated (165 d) pastes of 0.4 and 0.6 water-to-cement (W/C) ratios were dried directly from saturated surface dry state to 75%, SO%, 11%, and 0% relative humidity (rh). Fro...

Modeling of Hydration Kinetics and Shrinkage of Portland Cement Paste

MODELING OF HYDRATION KINETICS AND SHRINKAGE OF PORTLAND CEMENT PASTE

Structure and Physical Properties of Hardened Portland Cement Paste

Freezing of water in portland cement paste - an ac impedance spectroscopy study

The freezing of water in Portland cement paste was investigated using a.c. impedance spectroscopy techniques. Length change and impedance measurements on cooling and warming were obtained simultaneously using a specially designed coupling technique. A new descriptor of frost resistance is described in terms of the high frequency arc depression angle in the impedance plane. Curves of the depress...