Thermal expansion kinetics: Method to measure permeability of cementitiousmaterials: II, application to hardened cement pastes

A new approach to determine the permeability of cementitious materials is p resented in this paper. The method involves the measurement of the thermal dilatation of thin slabs of saturated cement paste. On heating and subseque nt isothermal holding, the sample first expands, then gradually contracts o ver time. The paste is treated as a porous solid with low permeability in w hich the initial expansion is partly due to the liquid expanding within the pores, putting both solid and liquid under stress. The time-dependent cont raction is due to the liquid flowing out of the pores to restore the pressu re to equilibrium, By analyzing the kinetics of the thermal expansion and c ontraction, the liquid permeability of the porous solid can be calculated, The theoretical analysis (presented in a previous paper) is applied to dete rmine the water permeability coefficients of selected cement pastes modifie d with silica fume and made with different water/solid ratios.