Advances in Conductometric Phase Transition Porosimetry
The paper describes advances in conductometric phase transition porosimetry (CPTP) test methods and procedures for measuring the pore size distribution of soil. Included are test methods and procedures for (1) measuring the “throat or neck” size distribution using CPTP cooling data, (2) measuring soil pore structure anisotropy using radial and axial CPTP test cells, and (3) measuring the pore size distribution of soil saturated with saline pore water. Test results are presented and discussed for each of these three advances. Some of the advantages of CPTP are that: (1) it is not necessary to dry specimens prior to testing, (2) it is possible to test relatively large specimens, (3) it is possible to investigate pore structure anisotropy, and (4) it is possible to measure the pore size distribution of specimens saturated with a variety of solutions. Some disadvantages are that: (1) saturation of specimens must be 100%, (2) pore size distribution is relative, thus an independent measure of total porosity in necessary, (3) maximum measurable pore size is about 1 µm, and (4) testing time is relatively long, about two days.