Tailoring the hierarchical pore structures in self-setting particle-stabilized foams made from calcium aluminate cement

This study shows for the first time that foam stabilization via in-situ hydrophobization of reactive cement particles is possible. By taking advantage of the initial "passivation" of freshly immersed calcium aluminate cement particles in water, hierarchical self-setting particle-stabilized foams can be produced using propyl gallate to in-situ hydrophobize the particle surface. The foam macrostructure (pore size and porosity) and the sub-micrometer structure inside the foam lamellae can be tailored independently by varying different parameters such as the cement and surface modifier concentration, or the setting temperature. The set foam microstructure is analyzed quantitatively and reveals pore sizes between 90 and 1650 μm and porosities up to 92 vol.%. The sub-micrometer structure is discussed qualitatively using SEM imaging and was found to feature surface-textured structures – a rather specific phenomenon of this material.