【目的】研究氧化石墨烯(GrapheneOxide,GO)对水泥砂浆在常温25℃以及105、200、300和450℃作用后力学性能的影响及机理。【方法】使用聚羧酸减水剂提高GO在水泥基体的分散,并使用紫外光谱证实GO在模拟孔溶液中分散良好。【结果】研究结果表明:掺入0.04%分散良好的GO可以改善水泥砂浆的抗折、抗压强度。掺入GO的水泥砂浆样品抗折强度在25、105、200、300和450℃时比未掺入GO样品分别提高了10%、7.6%、11.43%、16.64%和11.67%;而抗压强度则分别提高了13.95%、3.89%、6.38%、11.14%和4.15%。通过水化产物成分结构分析得出,掺入分散良好的GO可以提高水泥的水化程度;孔结构分析显示,GO的加入抑制了水泥砂浆在高温作用后孔结构的粗化,改善了孔结构,降低了孔隙率;微观结构观察显示水泥砂浆中的界面过渡区得到明显改善。

【Purposes】 This study investigated the mechanical properties of cement mortar with  highly dispersed graphene oxide after exposure to 105, 200, 300, and 450 ℃. 【Methods】 The disper⁃ sion of GO in the cement matrix was improved with the aid of polycarboxylate-based superplasticiz⁃ ers, and well-dispersed GO in the simulated pore solution was confirmed by UV-Vis. 【Findings】 The results show that the incorporation of 0.04% dispersed GO can improve the flexural and compres⁃ sive strengths of cement mortar. For cement mortar with 0.04% GO (by weight) (MPG) exposed to  temperatures of 25, 105, 200, 300, and 450 ℃, the flexural strengths are 10%, 7.6%, 11.43%, 16.64%, and 11.67% higher than that of cement mortar without GO (MP), respectively. And the  compressive strengths of MPG are 13.95%,3.89%,6.38%,11.14%, and 4.15% higher than that of  MP, respectivety. According to the composition and structure analysis of hydration products, the in⁃ corporation of dispersed GO improves the hydration degree. The mercury intrusion porosimetry re⁃ sults show that the addition of dispersed GO suppresses the coarsening of the pore structure, improves  the pore structure, and reduces the porosity after exposure to high temperatures. Scanning electron mi⁃ croscopy results revealed the significant improvement in the interfacial transition zone in cement mortar.