Abstract:
Alkali-activated foam concrete is a type of green, low-carbon and energy-saving material which combines the advantages of alkali-activated materials and foam concrete. The application and development of alkali-activated foam concrete are limited by its complex drying shrinkage values which affected by its complicated pores structure and hydration products that unlike cement. In this review, the capillary tension theory, the surface tension theory, the separation pressure theory and the interlayer water transfer theory were analyzed. Contrast the similarities and differences of contraction mechanism between alkali-activated foam concrete, cement base material and alkali-activated material. Meanwhile, the latest research progress of inhibiting drying shrinkage of alkali-activated foam concrete is summarized. Compared with cement-based materials, alkali-activated materials have larger drying shrinkage because of the different hydration products. The drying shrinkage of alkali-activated foam concrete is mainly related to the amount of foam, and the less slurry, the smaller the drying shrinkage value. Finally, this review points out the research and application of alkali-activated foam concrete and provides an effective way for its development economically and environmentally.