Model on Capillary Pressure saturation Relationship for Concrete

Abstract:

The paper presents an analysis of the cause to the capillary pressure. Then, the paper explores the relationship between the capillary pressure and the curved liquid water surface in pores and the relationship between the capillary pressure and relative humidity, respectively. Hysteresis effect occurs in desorption process in comparison with that absorption process, and the reason is illustrated by using cylindrical holes. A prediction model for the relationship between capillary pressure and saturation in desorption process is therefore set up on the basis of the hysteresis effect. Finally, an analysis is made of the influence of temperature on relationship between capillary pressure and saturation with a consideration of the adsorption isosteric heat effect. Analysis results show that with the rising of the temperature, the capillary pressure gradually reduces at the same saturation.

Key words:concrete; relative humidity; saturation; adsorption; desorption capillary pressure