Concrete porosimetry: Aspects of feasibility, reliability and economy

The opening operator of mathematical morphology is applied to section images in this paper for the assessment of pore characteristics, such as the size distribution, and critical pore size, in cement pastes. Moreover, the mean free spacing parameter is demonstrated as reflecting pore depercolation during cement maturation. This approach is compared with other popular methods for serving this purpose, encompassing the experimental technique of mercury intrusion porosimetry (MIP), Wood’s metal intrusion porosimetry (WMIP), the conventional method of image analysis by area histogram and a direct 3D approach by a simulation model. The comparison study reveals that the opening distribution technique is superior in terms of feasibility, reliability and economy; realistic and relevant structural information on pore space in cement pastes is obtained. Nevertheless, star volume measurements applied to section images are referred to as an interesting alternative to the proposed method. The proper characterization of pore size distribution, and assessment of critical pore size, and delineation of percolated porosity zones are of significant importance to permeability prediction of cementitious materials and thereby to durability studies of the materials.