Study On The Effect Of Addition Of Graphene On The Properties Of Cement-based Materials

Graphene oxide(GO)is a high-performance nanomaterial.Its current application in civil engineering materials shows considerable prospects.However,domestic research on graphene oxide in cement-based materials,its The achievements and technology are still immature.This paper mainly studies the workability of mortar,mechanical properties of mortar and concrete,dry shrinkage rate,resistance to chloride ion penetration and other aspects of graphene oxide with different dosages,and also passes microscopic tests.Methods(scanning electron microscope,mercury intrusion)were used to observe the microstructure of graphene oxide on the internal structure of cement-based materials and test the effect of graphene oxide on the porosity of hardened cement paste,and briefly analyze the graphene oxide in cement-based The mechanism of action in the material shows that although graphene oxide is detrimental to the workability of cement-based materials,it can effectively improve the mechanical properties of cement-based materials,reduce the shrinkage rate of concrete and improve the resistance of concrete to chloride ion penetration.performance.The graphene oxide dispersion used in this project was produced in Changzhou Sixth Element Co.,Ltd.,and its influence on the workability,mechanical properties,dry shrinkage and resistance to chloride ion penetration of cement-based materials was studied.The main research conclusions are as follows:(1)Graphene oxide can control the cement hydration products to form a microstructure with regular and dense planar morphology.At the same time,it can also better improve the pore size distribution of the cement-based material,thereby making the cement-based material structure more compact.(2)Graphene oxide has a detrimental effect on the flow performance of the net pulp,and with the increase of the amount of graphene oxide,the flow rate of the net pulp shows a downward trend,in which the addition of fly ash and mineral powder can slow down the flow rate of the net pulp.Speed,and with the increase of the amount of fly ash and mineral powder,this effect becomes more and more obvious.The optimal amount of fly ash is 30%,and the optimal amount of mineral powder is 40%;It will aggravate the decline rate of the flow rateof the clean pulp.With the increase of the amount of silica fume,the decrease rate of the flow rate of the clean pulp increases.(3)Graphene oxide can improve the mechanical properties of mortar,and the effect of improving the mechanical properties of mortar gradually weakens with age.The optimal amount of graphene oxide in pure cement,fly ash,ore powder mortar are all 0.01%,and the optimal amount of graphene oxide mixed with silica fume mortar is 0.03%;compared with the mortar test results,the addition of graphene oxide can also improve the mechanical properties of concrete,and shows that the improvement effect decreases with age Trend,but it is necessary to increase the amount of graphene oxide to obtain the best lifting effect.The optimum amount of graphene oxide for pure cement,fly ash,and ore powder concrete is0.03%.The best content of graphene is 0.05%;graphene oxide will reduce the shrinkage rate of concrete,the best content is 0.05% of cementitious materials,and the effect of reducing the shrinkage rate of concrete gradually decreases with the increase of age;Graphene oxide will reduce the chloride ion diffusion coefficient of concrete.The optimal dosage is 0.05% of the cementitious material,and the effect of reducing the diffusion coefficient of concrete at 28 days is stronger than 56 days.