Mineral carbonation for low-carbon foam-based construction materials - a review

Foam concrete is a widely used construction material due to its lightweight nature and good thermal and acoustic insulation performance, achieved through the incorporation of foaming agents in a cement-based matrix. However, like most construction materials, foam concrete is currently under significant pressure to reduce its carbon footprint by lowering its reliance on Portland cement. Mineral carbonation is a fast-growing technology to support low-carbon construction materials development. The present literature review analyses the extent to which mineral carbonation can be used for producing and hardening foams. The principles of mineral carbonation in relation to potential precursors and requirements for mineral foams are discussed, including the compatibility with foaming technologies. The discussion on the foaming process includes foam production, casting, and carbonation curing steps necessary to shape and harden lightweight construction products. The microstructure development relates to the material performance (mechanical, thermal, durability, acoustic) and CO 2 uptake potential. The reviewed literature shows that carbonation can increase both CO 2 uptake and mechanical performances, although the effects depend strongly on precursor composition, density, pore structure, and curing conditions. Reported CO 2 uptake ranges from approximately 6.1–8.6 wt% in Portland-cement-based CO 2 foam concrete to up to 28 wt% in slag-based carbonated autoclaved aerated concrete, while strength increases of approximately 35% have been reported. However, CO 2 uptake is not governed by porosity alone and also depends on the availability and reactivity of carbonatable phases and CO 2 transport. This review highlights that many aspects remain unresolved in terms of material design, production, performance assessment, and adaptations needed for extensive industrial adoption.