Effect Of Graphene Oxide On Mechanical Properties Of Cement-based Comprosites

Cement is the most widely used construction material today.It is widely used in housing construction,water conservancy and bridge engineering.Cement is the main component of cement-based materials.It condenses and hardens after contact with water.During this process,cement clinker minerals A series of complex physical and chemical reactions with water will generate a variety of hydration products.The microstructure of the hydration products is the source of its strength.The micro-cracks and micro-voids existing in the cement stone are also the root cause of brittleness and low toughness.It also indirectly causes problems such as poor durability.Graphene oxide is the product of graphene oxidation.Its excellent mechanical properties have caused widespread concern in enhancing the performance of cement-based materials.It has high specific surface area and surface chemistry,and can produce physical and chemical properties with cement-based materials.Chemical interactions can fundamentally improve the performance of cement-based materials.Therefore,it is considered to add graphene oxide to the cement-based materials to improve the microstructure of the composite materials,thereby enhancing the mechanical properties of the cement-based composite materials,and reducing the amount of cement while meeting the requirements of the building.However,the Hummers method is currently the most commonly used method for the preparation of graphene oxide.In this paper,p1GO（Peeling Graphene Oxide）and h GO（Hummers Graphene Oxide）were prepared by liquid phase intercalation stripping method and Hummers chemical method,and p2GO different from p1GO was prepared by liquid phase intercalation stripping method.Three GO sheet dispersions were obtained.The main research contents and results of this paper are as follows:（1）By using the Tyndall test and the ultraviolet-visible spectrophotometric test,the effects of the three dispersion modes of ultrasonic dispersion,dispersant plus mechanical stirring dispersion,and dispersant plus ultrasonic dispersion on the dispersion effect of GO solution were studied,and the optimal dispersion was determined the way.The research results show that:the dispersant plus ultrasonic dispersion method has the best dispersion effect,followed by the dispersant plus mechanical stirring,the ultrasonic dispersion effect alone is poor,and the dispersant plus ultrasonic dispersion and dispersant plus mechanical stirring dispersion are dispersed The effect is more stable.（2）The effects of the incorporation of three kinds of GO on the compressive and flexural strength of cement paste test blocks at different ages were explored.The research results show that:all three kinds of GO can improve the compressive strength and flexural strength of cement paste samples.With the increase of the amount of graphene oxide incorporated into cement-based materials,the compressive strength and flexural strength of hardened cement stone increase Decreases after large.The optimal dosage of the three kinds of GO is 0.02 wt%.At this time,the 3d flexural strength of cement paste samples mixed with p1GO,h GO and p2GO is increased by22.4%,27.4%and 34.7%respectively,and the compressive strength is increased by19.0%,14.6%,23.6%.p2GO has the most obvious effect on improving the mechanical properties of cement paste,and all three kinds of GO can effectively regulate the rate of early cement hydration reaction and accelerate the formation of early strength.（3）The effects of the incorporation of three kinds of GO on the compressive and flexural strength of cement mortar test blocks at different ages were explored.The research results show that:all three kinds of GO can improve the compressive strength and flexural strength of cement mortar samples.After reducing.For the compressive strength index,the optimal dosage of the three GO are 0.03wt%;for the flexural strength index,the optimal dosage of the three GO are 0.02%.At this time,the cement paste mixed with p1GO,h GO,and p2GO The 3d flexural strength of the sample was increased by 12.3%,14.8%,and 24.5%,and the compressive strength was increased by 14.6%,14.3%,and 17.1%,respectively.p2GO has the most obvious effect on improving the mechanical properties of cement mortar.All three kinds of GO can effectively regulate the rate of early hydration reaction of cement and accelerate the formation of early strength.（4）The effects of three kinds of GO on the microstructure of cement paste and the crystalline phase of hydration products were studied by scanning electron microscope and X-ray diffractometer.The results of the study indicate that the incorporation of the three GO will lead to a significant increase in the content of CH crystals in the hydration product,and the structure is more ordered and tight;the C₃S content is greatly reduced,the C-S-H gel is increased,and the size is smaller,which makes the hardened cement slurry The internal structure of the body is more uniform and dense to achieve the purpose of improving strength and toughness.