Model macroscopic-defect-free materials (MDFs) representing selected compositions in the system 4CaO · Al2O3· Fe2O3â 4CaO · 3Al2O3· SO3â hmpcâ H2O have been investigated by means of electron microscopy and mercury intrusion porosimetry. â Smooth spatial flowâ of unreacted grains into an intergranular hydrated-aluminium-monosulfate-related (AFm-like) phase and rigid linkage of clinker phaseâ intergranular massâ solidified polymer are demonstrated. Solidification of an intergranular Afmâ like phase in the presence of hpmc and pressure during syntheses causes partial elimination of pores; electron microscopy shows the remaining pores to be isolated at the micrometre level. Pore size distributions reveal the role of pressure in packing the pores with diameter r > 100 nm. Careful control of the mixing and pressing of reaction mixtures results in porosities in the range typical of MDFs. A scheme interrelating the atomic- and particle-level phenomena is outlined, and includes formation of Al(Fe)â Oâ C crosslinks between cement clinker and polymer.