氧化石墨烯增强水泥基复合材料的力学性能及微观结构
Mechanical properties and microstructure of graphene oxide reinforced cement-based composites

本文采用改进的Hummers法制备了氧化石墨烯（Graphene oxide，GO）悬浮液，通过FTIR、XRD和AFM等测试技术对GO晶体结构和尺寸形态进行了表征，考察了GO掺量和水灰比的变化对GO增强水泥基复合材料力学性能和微观结构的影响。结果表明：GO增强水泥基复合材料抗折抗压强度随GO掺量增加而先提高后降低，且对于抗折强度增强效果远超过抗压强度，当GO掺量为0.03%时，抗折强度达到最大值13.72 MPa；高水灰比条件下掺入GO对水泥胶砂强度的提高更显著；通过SEM对GO增强水泥基复合材料微观结构进行表征，发现GO能够优化水泥水化产物的微观结构形态，细化晶体尺寸，形成更加致密均匀的网络结构，从而改善水泥基复合材料的宏观性能。 In the present paper, the modified Hummers method was used to prepare the suspension of graphene oxide (GO). The structure and size of GO crystal were characterized by FTIR, XRD and AFM. By measuring the compressive strength, flexural strength and investigating the morphology of composite materials, the influence of the content of GO and water-cement ratio on the mechanical properties and microstructure of graphene cement-based composites have been systematically discussed. Test results indicate that flexural and compressive strengths of the graphene cement-based composites increase first and then decrease with the increase in GO content, and the growth rate of flexural strength is much higher than that of the compressive strength. The flexural strength of composites reaches the maximum value of 13.72 MPa when the optimal additive amount is 0.03%. The strength enhancement of cement mortar with GO under high water-cement ratio is more significant than that under relatively low water-cement ratio. The microstructure of cement-based composites material was characterized by SEM. It is found that GO can optimize the microstructure of cement hydration products, refine the crystal size and form a more dense and uniform network structure, and thus improve the macroscopic properties of cement-based materials. 国家自然科学基金（51578078）；湖南省自然科学基金杰出青年基金（2017 JJ1027）；长沙市科技计划项目（K1508020-31）；长沙理工大学研究生科研创新项目（CX2017SS07）