A STOCHASTIC-MODEL FOR THE PERMEABILITY CHARACTERISTICS OF SATURATED CEMENTED POROUS-MEDIA UNDERGOING FREEZING

As the temperature of a saturated porous medium drops, the water in th e pores starts to freeze. Since the temperature at which the phase cha nge takes place is dependent on the pore size, the permeability of the medium changes continuously. Simultaneously, due to the expansion of water on freezing, it is forced to migrate through the pore body thus inducing stresses in material matrix. The stresses developed and the c onsequent frost damage are therefore dependent on the change in the pe rmeability characteristics of the medium on freezing. This paper deals with the numerical prediction of permeability characteristics of poro us cemented media saturated with water undergoing progressive freezing . A bond percolation model is used to generate the pore structure acco rding to an assumed pore-size distribution. Permeability of the medium at various temperatures is computed by solving the network problem. T he computed results are compared with other analytical and experimenta l results. The proposed model predicts a threshold temperature below w hich permeability drops to zero. This phenomenon is crucial in develop ing a deeper understanding of the mechanism of frost damage to cemente d porous materials such as bricks, stone, concrete, etc.