Abstract: In order to improve the mechanical properties and durability of geopolymer concrete, experimental studies were conducted on the effects of incorporating polypropylene fibers of varying lengths and dosages on the mechanical properties, frost resistance, chloride ion corrosion resistance, and crack resistance of geopolymer concrete. Furthermore, based on SEM experiments, the mechanism of action of polypropylene fibers was further elucidated from a microscopic perspective. The research results indicated that the addition of polypropylene fibers can improve both the mechanical properties and durability of geopolymer concrete. Specifically, when the fiber content is 0%-0.6%, the improvement effect of geopolymer concrete becomes more pronounced with the increase of fiber content. However, when the dosage exceeds 0.6%, both the mechanical properties and durability begin to decline. SEM analysis further indicated that polypropylene fibers can improve the integrity and compactness of the matrix, thereby significantly improving the mechanical properties and durability of geopolymer concrete. Ultimately, the optimal dosage of polypropylene fibers is recommended to be 0.6% with a length of 12 mm.

Key words: polypropylene fiber, geopolymer concrete, mechanical properties, frost resistance, resistance to chloride ion corrosion