Mercury intrusion porosimetry (MIP) is widely used for the microstructural characterisation of porous solids. Comparatively few studies have employed the technique to characterise the size of particles within powdered samples. The present study uses the MIP technique to characterise the particle sizes of contemporary supplementary cementitious materials (SCMs), and in particular uses the technique to present particle size distributions, rather than a single mean size. Representivity of the technique for known limitations of non-spherical and porous particles are checked using the Scanning Electron Microscope. The findings indicate that the MIP affords a good approximation of particle sizes, including distributions, of spherical and non-spherical particles. The technique was also found to provide reasonable accuracy for estimating the particle sizes of highly porous particles, where distinction between inter-particle and intra-particle porosity was made
