Dispersion, properties, and mechanisms of nanotechnology-modified alkali-activated materials: A review

Alkali-activated materials are sustainable low-carbon cementitious materials with a promising future as an alternative to cementitious materials. Industrial solid waste can be consumed substantially in preparing alkali-activated materials, which are energy-efficient and environmentally friendly. Nanotechnology and nanomaterials play a crucial part in enhancing the properties of alkali-activated materials at the micro-scale. Based on their geometric dimensions, nanomaterials can be classified into different dimensional categories: zero, one, two, and three dimensions. Through systematic literature research and data statistics, this work reviews the analysis of the regularity and mechanism by which nanomaterials of different dimensions (0-dimensional, 1-dimensional, and 2-dimensional) influence the workability, rheology, physico-mechanical, durability, and volume stability of alkali-activated materials. In conclusion, nanomaterials' dispersion methods in alkali-activated materials can be classified as dry and wet dispersion (dispersion in water or activator). In addition, the method of dispersion has an impact on the performance of nanomaterials. The properties of alkali-activated materials paste relate to nanomaterial activity, dimension, morphology, and dosage. Nanomaterials in different dimensions have distinct structural and performance advantages that can significantly enhance alkali-activated materials' physical, mechanical, and durability properties and endow them with various functionalities (refractory, photocatalysis, electrical conductivity, etc.). Nanomaterial modification and enhancement technology have great potential for application in alkali-activated material property optimization.