Nanoparticle-stabilized foam with controllable structure for enhanced foamed concrete

•A novel ultrastable aqueous foam was prepared by adding nano-alumina (NA) particles to the prefabricated foam.•The NA-modified ultrastable foam improved the performance of foamed concrete.•The interaction between sodium dodecyl sulfate, NA and cement particles contributed to the formation of robust pore structures in foamed concrete. A novel ultrastable aqueous foam with controllable structure and Plateau borders was synthesized by adding polyvinyl alcohol (PVA) and nano-alumina (NA) complexes to the anionic surfactant sodium dodecyl sulfate (SDS). The influence of NA-modified foam on the mechanical properties and durability of foamed concrete was investigated. The experimental results revealed that PVA and NA effectively decreased the drainage of foam while expanding the liquid film thickness of Plateau borders, which stabilizes the foam. The excellent stability is attributable to the molecular interaction between NA and SDS, which allows the nanoparticles to adhere to the foam surface and form a dense granular film layer. Moreover, due to the interaction between SDS and NA, the precast foam forms robust pore structures in the hardened foamed concrete, which improves its properties.