Study On Hydration And Mechanical Properties Of Graphene Nanoplatelets/Graphene Oxide Reinforced Cement-based Composites

Cement-based materials are one of the most commonly used materials in construction and infrastructure construction.However,poor crack resistance,low tensile strength and poor strain capacity limit its application,so it is of great significance to study the improvement of mechanical properties of cement-based materials.With the rapid development of science and technology,nanomaterials have been researched and used in cement-based materials to improve their mechanical properties and durability.Graphene is a two-dimensional carbon nanomaterial with extraordinary physical and chemical properties.Its special two-dimensional planar structure and higher aspect ratio make it have advantages unmatched by other nanomaterials,and is widely used to manufacture high-performance composite materials.This paper combines existing research and introduces two kinds of derivatives of graphene—graphene nanosheets and graphene oxide into cement-based materials,based on ordinary silicate hydration theory and micro-characterization technology of cement-based materials.The effects of graphene nanosheets and graphene oxide on the hydration and mechanical properties of cementbased materials are discussed.The main contents are as follows:(1)Preparation of graphene nanoplatelets / graphene oxide cement-based composite materials.Based on the existing research,this article uses ultrasonic vibration combined with the addition of surfactants to disperse graphene nanoplatelets / graphene oxide to prepare a uniform dispersion solution,and refers to relevant specifications to prepare cement-based composite materials for related tests.(2)Analysis of the effect of graphene nanoplatelets / graphene oxide on cement hydration.Based on the hydration theory,the hydration heat test,scanning electron microscopy test,X-ray diffraction test and other tests were carried out on the composite cement paste.The results show that: graphene nanoplatelets and graphene oxide will not change the basic process of cement hydration and the types of cement hydration products.Graphene nanoplatelets can be filled in the gaps and interconnected with other hydration products to form a dense structure.Graphene oxide can reduce the temperature of the initial reaction of cement hydration and promote cement hydration,and It can regulate the shape of cement hydration products,so that the hydration products can be attached to the surface and grow on the surface to form flower cluster crystals.In addition,graphene nanoplatelets and graphene oxide can reduce the amount of calcium hydroxide in the hydration product and refine its size.(3)Analysis of the influence of graphene nanoplatelets / graphene oxide on the mechanical properties of cement-based materials.Refer to relevant specifications,combine microscopic means to test and analyze the flexural and compressive properties of composite cement mortar,and combine ultrasonic testing to test and analyze the flexural and compressive properties of composite concrete and dynamic elastic modulus.The results show that the incorporation of graphene nanoplatelets and graphene oxide can improve the mechanical properties of cement mortar and concrete,the early strength improvement is more obvious,and the mechanical property improvement rate of cement mortar is better than that of concrete.Whether in cement mortar or concrete,the lifting capacity of graphene oxide is better than graphene nanoplatelets.