Modification Mechanism Of Graphene Oxide On Thermal Conductivity Of Cement And Temperature Control Simulation Of Gravity Dam

Large volume concrete is most commonly involved in hydraulic engineering,and its hydration heat often causes a large temperature difference between the inside and outside,leading to thermal stress.High temperature stress is one of the main causes of cracking in concrete buildings.Graphite oxide(GO)is a two-dimensional nano material with excellent performance.It has high hydrophilicity,large specific surface area,excellent mechanical properties,and high thermal conductivity,and has been applied in modified cement in recent years.Research based on composite materials has received widespread attention.The current research mainly focuses on mechanical properties,hydration properties,and micro structure.GO/cement-based composites exhibit excellent mechanical properties and show great application prospects.With the deepening of research,it has been found that GO enhances the hydration heat and mechanical parameters of cement.In order to better utilize the improvement effect of GO on cement materials and avoid the harm caused by temperature stress,it is necessary to study the thermal properties of GO/cement composite materials.This article explores the thermal conductivity and micro performance of GO/cement materials,and simulates the temperature and stress fields of a gravity dam using experimental measurement parameters,providing a certain reference for the application of GO in engineering.The main content of the study is as follows:(1)Observe the porosity and microstructure of cement mortar through nuclear magnetic testing,scanning electron microscopy,and thermogravimetry.The experimental results indicate that GO promotes the generation of hydrated crystals,increases the density of cement mortar,and reduces the porosity of cement mortar and the proportion of macropores to the total number of pores.In addition,the increase in density of cement mortar and the decrease in macropore content enhance the thermal conductivity of cement mortar.(2)Through the analysis of the thermal conductivity test results,it is found that the addition of graphite oxide can enhance the thermal conductivity of cement materials.With the increase of GO content,the thermal conductivity of cement slurry first increases and then decreases.A 0.02%GO content has the best effect on improving the thermal conductivity of cement materials,and the improvement effect is better in the younger age group than in the older age group.Therefore,GO can be used to optimize the thermal conductivity of cement materials.(3)The temperature field and stress field of a concrete gravity dam are simulated,and the maximum temperature and maximum stress of each zone of the dam under different GO dosages are obtained according to the distribution of temperature field and stress field.The analysis of simulation results shows that the maximum temperature of the dam body decreases when 0.02%GO is added,the maximum stress is increased at 0.02%and 0.05%,and the temperature difference between inside and outside concrete is reduced when the GO content is 0.02%,and the thermal conductivity is increased so that the temperature generated by hydration heat can be released faster After comparative analysis,when the dosage reaches 0.02%,the temperature field stress field can meet the temperature and stress control standards,and the stress surplus is large,so it is considered that the gravity dam is more suitable to choose 0.02%dosage.