A state-of-the-art review on fracture properties of geopolymer composites

In recent years, due to the continuous increase of environmental pollution, green and environmentally friendly building materials have received key attention from researchers. Compared with traditional concrete materials, geopolymer composites (GC) have the capacity to lessen CO2 emissions and decrease energy usage. Evaluating the fracture properties of GC is necessary because it is necessary to ensure that structures using GC are safe. This study presents an overview of the advancements in scholarly research concerning the fracture characteristics of GC. The review includes test methods and techniques, evaluation parameters, fracture models, and influence factors of fracture performance. The findings reveal that choosing the correct fracture model is indispensable for accurately assessing the fracture behavior inherent in GC. Applying satisfactory precursor materials, adopting appropriate content of the alkali-activator, adding a certain dosage of fibers and nanofillers can enhance the fracture resistance of GC. When using additives to improve the fracture resistance of GC, the dosage of the additive needs to be considered. For example, incorporating steel fibers (SF) at a range of 0.5-1.5 % into GC usually enhances the material's fracture performance, but this improvement effect weakens when the content of SF is too high. This review aims to guide researchers towards a structured understanding of the fracture behavior exhibited by GC and boost the integration of GC into practical engineering applications.