Reassessment of mercury intrusion porosimetry for characterizing the pore structure of cement-based porous materials by monitoring the mercury entrapments with X-ray computed tomography

Abstract

Mercury intrusion porosimetry (MIP) is a vital method for assessing the pore structure of cement-based porous materials (CBPMs), but its applicability remains to be clarified. Herein we employed X-ray computed tomography (X-CT) to trace the entrapped mercury in two hardened cement pastes (HCPs) after MIP tests to reassess the method for pore structure characterization. Four different maximum pressures were employed in the MIP tests. Results show that the maximum intrusion pressure had no significant influences on the threshold pore sizes, but impacted the mean pore sizes that were linked to the pore intervals. X-CT can measure the mercury drops entrapped in macro pores. A pore model with the pore structure of thick chamber connected with thin throats was proposed to associate the links between the MIP and X-CT data. The combined uses of MIP and X-CT provide new insights in better understanding MIP results and the possibility for quantitative pore structure characterization of CBPMs.