Abstract:
Due to the excellent mechanical properties, good durability, and low carbon and environmental friendly synthetic characteristics, geopolymers are considered as the most promising new cementitious materials to replace portland cement. Unfortunately, there are some defects in geopolymers: On the one hand, coal-based solid wastes with low calcium content such as fly ash and coal gangue can only obtain high strength cured at a high temperature, while the strength of geopolymers prepared at room temperature is low; On the other hand, geopolymers have disadvantages such as high brittleness and low toughness, which seriously restricts the large-scale application of geopolymers. In this study, the effects of mechanochemical effect, compounding of silicon, aluminum and calcium substances, fiber and organic matter modifications on the mechanical properties of geopolymers were reviewed, and the mechanisms of strengthening and toughening were also summarized. Finally, some suggestions were made for related studies that needs to be carried out in depth in the future.