Study On Salt Corrosion Resistance Performance Of Cement Mortar With Thermal Reduced Of Graphene

At present,nano-materials as a cement-based material modifier is gradually applied to the building materials,and graphene as a two-dimensional nano-materials,has a large surface area,a high surface energy and a large surface tension,showing significant nano-size effects and surface effects,not only can significantly improve the toughness of cement concrete,but also improve Its impermeability and durability.Therefore,this paper chooses hot-reduced graphene as modifier,and studies the physical,mechanical and salt-corrosion resistance of cement-based materials by macro-test and micro-test.At the same time,the mechanism of thermal reduction of graphene on salt corrosion resistance was studied deeply.In this paper,the thermal reduction of graphene(RGO)suspension was obtained by thermal reduction and ultrasonic dispersion.The structure and properties were characterized by XRD,SEM,TEM,TEM,AFM,FTIR and BET.The dispersion effect of four different dispersants on the thermal reduction of graphene in alkaline aqueous solution was compared by sedimentation method,dindal effect and absorbance test.On the basis of this,the effects of different amount of thermally reduced graphene on the physical properties of cement paste and the mechanical properties of cement mortar were studied.The microbial test was used to study the hydration activity of cement hydration products.Finally,the durability and mechanism of thermal reduction of graphene cement mortar in different corrosive environments(concentration of 5% NaCl and Na2SO4 solution),different external environment(dry-wet circulation,total immersion)were explored.The results show that the graphene oxide is successfully reduced into graphene powder by high temperature thermal reduction method,and the conversion rate is high and the reduction is more complete.The slump retention polycarboxylate superplasticizer can disperse the thermal reduction of graphene uniformly and stably in the cement-based material without sedimentation and agglomeration.When the amount of thermal reduction of graphene increased,the standard consistency of cement-based composites increased with the amount of water,the setting time and the water absorption rate in different degrees,and the fluidity And the bulk density of the cement mortar specimen decreases with the increase of the content of the thermal reduction graphene.In addition,when the content of thermally reduced graphene was 0.9%,theflexural strength and compressive strength of cement mortar test piece were increased by 18% and 11% respectively,and the flexural strength and compressive strength increased by 9.6% and 5%.After the total immersion and dry-wet circulation,the mass change rate of the 0.9% thermal reduction graphene cement mortar was the smallest,and the change rate of the mechanical strength of the cement mortar was also the smallest.Through the microanalysis,it can be seen that the internal structure of 0.9%thermal reduction graphene cement mortar is more dense,and the hydration products are arranged neatly and without obvious corrosion,showing excellent salt corrosion resistance.