The theoretical basis of mercury intrusion porosimetry is reviewed, and the limitations of the Washburn equation as a means of converting the test data to a pore-size distribution curve are discussed. A procedure is suggested to distinguish the volume of pores with uniform radii from the volume of nonuniform of "ink-bottle" pores. The depressurization curve that results from reducing the pressure on mercury to allow retraction and ejection of mercury from the pores does not coincide with the pressurization curve. This hysteresis is attributed to the presence of ink-bottle or nonuniform pores. Physicochemical factors such as chemisorption and the difference in the contact angle of advancing and retreating mercury menisci contribute slightly to this hysteresis. Consideration of pore geometries demonstrates that the ejection pressure may not be equal to the intrusion pressure for a pore of given size. A comparison of the intrusion, depressurization, and reintrusion of two hypothetical samples illustrates the advantage of the second intrusion for interpreting pore-size distribution curves. The second intrusion gives the distribution of uniform pores and volumes of ink-bottle pores intruded at each entrance diameter. Finally the second-intrusion method is applied to portland cement pastes with a 0.4 water-cement ratio that were hydrated for 3 and 60 d. It is observed that 60 to 64 percent of the porosity is in uniform pores that have a size distribution curve similar to the first-intrusion curve. /Author/
[1]
R. P. Mayer,et al.
Mercury porosimetry—breakthrough pressure for penetration between packed spheres
,
1965
.
[2]
R. P. Mayer,et al.
Mercury Porosimetry: Filling of Toroidal Void Volume Following Breakthrough between Packed Spheres
,
1966
.
[3]
S. Kruyer,et al.
The penetration of mercury and capillary condensation in packed spheres
,
1958
.
[4]
L. C. Drake.
Pore-Size Distribution in Porous Materials
,
1949
.
[5]
Douglas Windslow,et al.
A Mercury Porosimetry Study of the Evolution of Porosity in Portland Cement : Technical Publication
,
1969
.
[6]
L. Dewit.
Studies on pore structure of adsorbents and catalysts: III. Comparison of pore size distributions determined in chrysotile and zirconia samples by mercury porosimetry and nitrogen capillary condensation
,
1975
.
[7]
H. P. Freeman,et al.
Physical Structure of Fertilizer Materials, Pore Structure of Phosphate Rock and Triple Superphosphate
,
1961
.
[8]
E. W. Washburn.
Note on a Method of Determining the Distribution of Pore Sizes in a Porous Material.
,
1921,
Proceedings of the National Academy of Sciences of the United States of America.
[9]
Sidney Diamond,et al.
Pore Size Distributions in Clays
,
1970
.
[10]
L. K. Frevel,et al.
Modifications in Mercury Porosimetry.
,
1963
.
[11]
H. Meyer.
Pore Distribution in Porous Media
,
1953
.