High-Temperature Properties of Cement Mortar with Highly Dispersed Graphene Oxide

[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 dispersion of GO in the cement matrix was improved with the aid of polycarboxylate-based superplasticizers, 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 compressive 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 incorporation of dispersed GO improves the hydration degree. The mercury intrusion porosimetry results 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 microscopy results revealed the significant improvement in the interfacial transition zone in cement mortar.