COMPARISON OF MEASURED AND CALCULATED PERMEABILITIES FOR HARDENED CEMENT PASTES

The experimental and calculated permeabilities of hardened cement past es were compared. Experimental data for water permeability was obtaine d from the work of Nyame and Illston in 1980 on neat pastes with water -to-cement ratios (w/c) between 0.23 and 1.0. Mercury intrusion porosi metry (MIP) and impedance spectroscopy (IS) measurements were performe d on equivalently prepared specimens. Then the Katz-Thompson relation was used to calculate permeability. Calculated results track well with experimental data as a function of time, with the experimental value of permeability slightly higher at most times. The correlation between experimental and calculated permeabilities, at all times, are within 1.5 orders of magnitude. The largest differences occurred at late time s for the samples with low w/c ratio. This calculated permeability is quick, relatively simple and appears to give reasonable results when c ompared to conventional water intrusion methods.