Abstract: Graphene oxide (GO) were prepared by Hummers method and ultrasonic dispersion method; the structure was characterized by TEM，FT-IR and X-ray photoelectron spectroscopy. The influence rules of single GO，both GO and PC addition on the flexural strength and compressive strength of cement mortar were studied. The results indicate that with the presence of polycarboxylate superplasticizer (PC)，GO has good dispersion ability in cement-water system; after adding GO and PC，the flexural compressive strength of cement mortar for 3 and 28 days is improved by 20% higher than that of single doped GO or single doped PC specimen，and the strength at early stage is improved significantly. The scanning electron microscope (SEM) and the pore size analysis of cement paste show that GO can participate in the hydration process of cement and regulate the growth of cement hydration crystal; GO modified cement mortar C-S-H crystal can have dense，neat and regular growth on the GO layer，so the internal structure of the specimen is more dense，which makes GO modified cement mortar exhibit excellent mechanical properties.

Key words: highway engineering, cement mortar, mechanical properties, microstructure, hydration of cement, graphene oxide

摘要： 采用Hummers法和超声波分散法制备氧化石墨烯(GO)，并通过透射电镜、红外光谱、X射线光电子能谱等微观手段对其结构进行了表征。研究了单掺 GO、同时掺加GO和聚羧酸减水剂(PC)对水泥砂浆抗折抗压强度的影响规律。结果表明：在PC存在下，GO在水泥-水体系中有较好的分散能力；复掺GO与PC 后，水泥砂浆3 d和28 d抗折抗压强度比单掺GO或者单掺PC的试件的强度提高了20%以上，且早期强度提升显著。经扫面电镜(SEM)及水泥净浆孔径分析研 究表明，GO能参与水泥水化过程以及对水泥水化晶体生长有模板调节作用，GO改性的水泥砂浆的C-S-H晶体可以致密整齐规整生长在GO片层上，试件内部 结构更加密实，从而使GO改性水泥砂浆呈现出优异的力学性能。

关键词: 道路工程, 水泥砂浆, 力学性能, 微观结构, 水泥水化, 氧化石墨烯