Effect Of Graphene Oxide Nanosheets On The Mechanical Properties And Microcosmic Performance Of Concrete

Concretes has been widely used in the construction industry due to its high compressive strength and the easy availability of sand,gravel and cement,relatively low cost,fire resistance,and durability in performance;but at the same time,the concrete’s resistance to bending and bending is relatively low.It is relatively low and brittle fracture is liable to occur,and it is easily affected by the external environment during service and is prone to durability failure.Although the mineral concrete,fiber concrete and nanometer concrete developed subsequently improved the mechanical properties and microstructure of concrete to a certain degree,there are still some deficiencies,such as the lack of concrete alkali reserves caused by the equal replacement of cement by minerals,and the fiber in cement.Uneven dispersion and nano-particles have limited cracking resistance to concrete.Graphene oxide(GO)is a two-dimensional nanosheet material that has been gradually developed and applied in recent years and is an intermediate product of the graphene to graphene reaction process.Compared with other nanomaterials,GO has large specific surface area,good hydrophilicity,and excellent mechanical properties.Many scholars have added GO to cement-based composite materials to improve their mechanical properties,transmission performance,and durability performance.And have achieved good results.In the existing research,most of the scholars are using the laboratory to prepare GO,and focus on GO cement mortar and cement paste,the study involving GO concrete is still insufficient.This thesis aims to add a relatively low-cost GO to study its effect on the mechanical properties of cement mortar and concrete.The main research contents are as follows:1)Adding 0.02%,0.03%,0.04%,0.05%,0.06%,0.08% and 0.10% of GO in cement mortar to study the effect of GO on the flexural strength and compressive strength of cement mortar.The results show that GO has a significant effect on the early strength and compressive strength of cement mortar.The increase rate of anti-breaking strength is the highest at the content of 0.03%,the increase rate is 57.5%,and the increase rate of the compressive strength is the highest when the content is 0.06%,the rate of improvement was 37.23%.2)Adding 0.03%,0.06%,and 0.08% GO by weight of cement to the concrete to study the effect of GO on the mechanical properties of ordinary concrete,including cube compression,flexural,splitting tensile,axial compressive strength,and elastic modulus.The results show that the compressive strength,flexural strength and axial compressive strength of concrete increase with the increase of GO production.The optimum content of split tensile strength is 0.03%.The elastic modulus decreases with the GO content first and then increases.3)The microscopic testing methods such as scanning electron microscopy(SEM)and X-ray diffraction(XRD)were used to investigate the relationship between the changes in the microstructure of GO concrete and the macroscopic mechanical properties,and the enhancement mechanism of GO on concrete was analyzed.The micro cracks inside the concrete can be filled with GO from the scanning electron microscope image,and the results of XRD test show that GO can effectively control the growth of CH crystal and can make CSH grow in a large amount.This thesis is focused on the mechanical properties of GO concrete.It is a transitional study of cement-based materials to concrete components.It verifies the applicability of the empirical relationship of the existing concrete mechanical properties to GO concrete.The research results will provide scientific basis for the fundamental and engineering of GO concrete,and it is of great significance to promote the development of graphene and graphene oxide industry.