氧化石墨烯水泥净浆的力学性能与微观结构的分形特征

Mechanical properties and fractal characteristic of microstructure of cement paste with graphene oxide

采用改进Hummers法和超声波分散法制备氧化石墨烯片层分散液,利用傅里叶红外光谱(FTIR)和X-射线衍射(XRD)表征GO;测试了不同掺量氧化石墨烯水泥净浆的抗折和抗折强度,通过SEM扫描了水泥净浆水化产物微观图像,结合分形理论计算SEM图像的分形维数并分析其变化规律,探讨了抗压强度与分形维数的关系。研究表明:氧化石墨烯可以有效提高水泥净浆的力学性能和改善其微观结构;分形理论能定量分析不同掺量氧化石墨烯水泥净浆的微观结构变化特征;分形维数随氧化石墨烯掺量的增加呈现逐渐降低的趋势;分形维数和水泥净浆抗压强度存在着良好的二次函数关系,其水泥净浆的抗压强度随分形维数的增加而降低,其最佳掺量为水泥质量的0.03%。

Graphene oxide dispersion were prepared by improving Hummers method and ultrasonic dispersion method.The resulting GO dispersion were characterized by FTIR and X-ray photoelectron spectroscopy.The compressive strength and flexural strength were tested,and the meso-structure of concrete paste hydrationproducts were captured by the SEM.The fractal dimension of the surface and the variations of concrete paste hydration products were calculated based on fractal theory,and the relationship between the strength and fractal dimension were studied.It is shown that graphene oxide can improve the mechanical properties and the meso-structure of concrete paste.Fractal theory can quantitatively analyze the meso-structure of concrete paste with graphene oxide,the fractal dimensions decrease with an increase of graphene oxide volumetric contents.It is revealed that there is a quadratic function relation between compressive strength of concrete paste and fractal dimensions,and the compressive strength of concrete paste decreases with the increase of fractal dimensions.The optimal dosage of graphene oxide is 0.03%of the cement quality.