▎ 摘　　要

As a new type of nano carbon material, graphene oxide (GO) has attracted extensive attention in the academic field over recent years due to its abundant oxygen-containing functional groups and large specific surface area, which can improve the microstructure and mechanical properties of cement-based materials. However, the effect of GO on the chemical shrinkage of cement-based materials remains unclear. Therefore, in this study, to reveal the chemical shrinkage characteristics of GO/cement composite paste (GO/CP), the chemical shrinkage of cement-based composite paste with different water/cement ratios (0.32, 0.42, and 0.52), different mass fractions of GO (0 wt%, 0.01 wt%, 0.03 wt%, and 0.05 wt%), and different mass fractions of polycarboxylate superplasticizer (PC) (0 wt%, 0.02 wt%, and 0.03 wt%) were measured using the volumetric method. The results showed that the chemical shrinkage of GO/CP increases significantly with the increasing water/cement ratio. The addition of PC appeared to compound GO/CP chemical shrinkage, showing a trend of first augmenting and then reducing with the increasing PC content. For the same water/cement ratio, the chemical shrinkage of the GO/CP specimen was lower than that of the normal cement paste (NCP). When the GO content reached the range of 0.03 wt%-0.05 wt%, the shrinkage value reached the minimum; and when the water/cement ratio was 0.42, the growth rate of chemical shrinkage of the GO/CP specimen in the middle and late hydration processes was significantly larger than that of NCP The analysis revealed that the regulating effect of GO on cement-based materials is mainly reflected in the refinement of the pore structure and bonding behavior of the hydration product Ca(OH)(2). In addition, to determine the influence of GO and PC on chemical shrinkage of GO/CP, the existing model for chemical shrinkage of NCP was modified and the functions K(xi, t) and P(lambda, t) were introduced as impact parameters, after which a suitable prediction model for chemical shrinkage of GO/CP was established by curve fitting. This study provides a theoretical basis for improving the performance of cement-based materials and clarifying the function mechanism of GO.