Evaluation of zirconia modification on the durability of natural fiber-reinforced cement composites using accelerated aging

In this research, the main target focuses on accelerating aging tests for the evaluation of durability performance on ZrO₂-modified fiber-reinforced cement composites. Then, the study focuses on the comparison between two alkali-resistance behaviors (i.e. alkali hydrolysis and mineralization) of unmodified and ZrO₂-modified fibers in various controlled alkali solutions. For such purposes, the mechanical strengths of the composites under accelerating aging were measured. The thermal stability of embedded fibers, the evolution of hydration products on the fiber surfaces, and the interface compatibility were also studied to understand the mechanism behind the potential enhancement of durability. Besides, the alkali resistance of fibers was investigated by measuring the tensile strength loss. Results show that the composites reinforced with ZrO₂-modified fibers retain their high mechanical strength, even when subjected to long-term wetting-drying cycles. Moreover, ZrO₂ modification can significantly reduce or even prevent the precipitation of portlandite and ettringite on the surfaces of the embedded fibers. According to alkali resistance tests, fibers with ZrO₂ film exhibited superior resistance. The results of the durability of NFRCCs under accelerated aging conditions accelerate their practical application in outdoor building projects.