Progress, current thinking and challenges in geopolymer foam concrete technology

Geopolymer foam concrete (GFC) has attracted significant research interest in various fields, thanks to their porous structure which brings the inherent merits of lightweight, acoustic and thermal insulation, and fire resistance. This review is focussed on three primary functional properties of GFC, namely mechanical properties (compression and flexural strengths), serviceability (thermal conductivity, sound absorption, and fire resistance), and durability. The functional properties depend on the fundamental fresh and hardened properties (rheology, stability, density, porosity and pore morphology), and all these properties are decided by the materials, foaming methods, curing conditions, and additives. A clear insight to these relationships and the ways of optimising the performance as a construction material are therefore presented. Also, the challenges towards the large-scale production and real-world application of GFC are discussed. The identified research needs include studies on fresh properties, durability, processing techniques to attract industrial applications, and developing 3D printable GFC. •Materials and processing techniques in geopolymer foam concrete are reviewed.•Insight to the engineering properties of geopolymer foam concrete is presented.•Discussion on the rheology and the stability of fresh geopolymer foam concrete.•Challenges towards large-scale production and real-world applications are addressed.