2016 Volume 27 Pages 67-76
The isosteric heat of adsorbed pore water in hardened cement pastes was determined under atmospheric pressure and a prediction model of isosteric heat using an absorption isotherm model was proposed. An experimental system in which changes in vapor pressure can be calculated according to the temperature data during heating and cooling was developed, and the isosteric heat was evaluated with the Van’t Hoff plot. The value of isosteric heat was found to increase with decreases in water content, and the increase was particularly pronounced for water content of less than 15%. The calculation results of the proposed model agree well with the experimental results on the whole, indicating that the proposed model may be suitable as a constitutive law expressing the relationships between water content and isosteric heat.
