Geopolymer foams are promising sustainable lightweight materials combining insulation efficiency with interesting mechanical and fire resistance properties. Controlling their pore size remains challenging because intrinsic foam aging processes act before hardening. During the PhD thesis of Asmaa Kaddami (2016-2019) we highlighted a physical approach to counteracting aging processes in fresh geopolymer foams and to maintaining the pore morphology that has been set initially by mixing metakaolin suspension with precursor aqueous foam. More precisely, it was shown that arrest of foam aging can be achieved if solid particle concentration in the suspension is larger than a critical value which is proved to depend on both bubble size and gas volume fraction. This behavior was understood through the jamming transition occurring for the metakaolin suspension when confined in the foam network, providing significant solid elasticity against bubble motions. The general significance of the reported result makes it useful, as a complement to chemical formulation, for designing morphology-controlled geopolymer foams.
– A physical approach towards controlling the microstructure of metakaolin-based geopolymer foams, A. Kaddami, O. Pitois, Cement & Concrete Research (2019) 124, 105807.
– Mousse de géopolymère et son procédé de fabrication, patent FR 1762432A