Mechanisms of graphene oxide enhancement of freeze-thaw durability in cementitious composites

Graphene oxide (GO) has demonstrated significant potential for optimizing cement-based materials and improving the freeze-thaw resistance of cementitious composites. However, the intrinsic randomness of cement complicates quantitative evaluation of GO’s enhancement effects and the identification of underlying reinforcement mechanisms. In this study, the microstructure of GO-reinforced cementitious composites after freeze-thaw exposure is systematically examined using metal intrusion techniques, backscattered electron imaging, and deep learning-based analysis. Complementary macroscopic mechanical tests are conducted to correlate microstructural characteristics with mechanical performance. The results show that GO promotes cement hydration through nucleation and pore-infilling effects, reducing overall porosity by 7.2-10.5%, with a particularly notable decrease in large pores (equivalent pore diameter greater than 10 μm, reduced by 57-68%). Moreover, GO suppresses microcrack propagation via a bridging effect, enabling the cement matrix to maintain an intact microstructural framework during freeze-thaw cycles. After 30 freeze-thaw cycles, the compressive strength of GO-reinforced cement reaches 45.4 MPa, representing an increase of up to 28.1% compared to plain cement. Furthermore, convolutional neural networks combined with deep Taylor decomposition are employed to identify microstructural features enhanced by GO, revealing a finer, more uniform, and independent distribution of micropores. This study clarifies the reinforcement mechanisms of GO and supports its application in enhancing freeze-thaw durability. • An ideal reinforcing effect of GO on cement can be obtained under freeze-thaw conditions. • The microstructure optimization effects of GO are systematically analyzed. • Micropore characterization and DTD modeling identify GO-enhanced regions. • The reinforcing mechanisms of enhanced antifreeze properties by GO are revealed.