| At present,cement concrete is still the cheapest and the most widely used materials in the construction of our country.The microstructure has a decisive influence on the mechanical properties of concrete and concrete durability.Many kinds of nano materials were used in the concrete,and the affects were proved positive.This article begins with the preparation of different size of graphene oxides,And the structure of GO was characterized by SEM?XRD?FT-IR,graphene oxide is divided into cement based material by the combination of surfactant and ultrasonic dispersion.The effects of different dosage and sizes of graphene oxide on workability and mechanical properties of cement-based materials were investigated,The experimental results show that within a certain range of dosage,the flexural strength and compressive strength of cement mortar are improved,when the dosage of GO is 0.04%,the cement mortar flexural strength and compressive strength were increased by 21% and 15.9%;graphene oxide nanosheets with large size can improve the strength of cement mortar better.The addition of GO can result in the descent of fluidity of cement paste and mortar,and the setting time of cement was shorted as the amount of admixture increased.The paste and mortar were investigated by XRD and SEM analysis,it can be found that GO would not change the hydration products of cement,but to promote the hydration of C2 S.Graphene oxide has a function of promoting and template formation on the hydration of crystal products,which can promote cement hydration products formed crystalline neat compact.The effect of GO addition on freeze–thaw resistance in hardened cement mortars was investigated refer to ASTM C666.Freeze–thaw cycle tests show a weight loss of approximately 0.78% after 150 cycles in the control mix compared to approximately 0.55% weight gain in 0.05% GO mix.The variation in length showed a similar trend to weight loss.The 0.01% GO mix represents the best frost resistance among all the specimens. |
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