Porous alkali-activated materials

Abstract Alkali-activated materials (AAMs), and geopolymers as their subgroup, are a valuable addition to the building materials with lower carbon footprints. Porous AAMs have promising performance, unique properties, and their carbon emissions are low due to the use of industrial wastes as raw materials. Porous AAMs can be prepared by several different methods such as direct foaming, sacrificial filler method, and 3D printing. Pore size plays a major role in defining, for instance, mechanical, thermal insulation, acoustic, and permeability properties. Strength improvement with a high-temperature exposure of the AAM makes it an excellent material for fireproofing and refractory linings compared to the conventional foam concrete made of Portland cement. The low thermal conductivity and high sound absorption capacity of the porous material is utilized for its application in insulation purposes. AAMs are now quickly progressing in the construction and environmental applications of the civil engineering sector. The development of foam with precise properties to satisfy the requirement for this specific application will open new market opportunities. This chapter covers the different preparation methods of porous AAMs, their characterization techniques, properties and functional relations, and applications in civil engineering.