Static And Dynamic Properties And Microscopic Mechanism Of Recycled Aggregate Stabilized By Graphene Oxide Modified Cemen

With the rapid economic development,the reconstruction of urban infrastructure and housing construction has generated a large number of construction demolition waste.The large-scale landfill and accumulation of construction waste not only waste land resources,but also do not conform to the concept of waste recycling.Among them,road demolition waste after crushing and screening can be mixed with cement as a road building material to build roads,and graphene oxide(GO)can improve the performance of cement-based materials.Therefore,graphene oxide modified cement is used to stabilize the recycled aggregate and realize the recycling of road demolition waste.Based on this,this study studies the stabilized recycled aggregate of graphene oxide modified cement from the aspects of modified strength change,durability,dynamic characteristics,etc.The main contents are as follows:(1)Effect of GO on mechanical properties of cement stabilized recycled aggregateThrough unconfined compression test and unconsolidated undrained shear test,the influence of graphene oxide content,curing age and other factors on the mechanical properties of cement stabilized recycled aggregate is studied: the influence rule of compressive strength and shear strength.The results show that the compressive strength and shear strength of cement stabilized recycled aggregate are improved by adding GO,and with the increase of GO content,the compressive strength and shear strength first increase and then decrease.When the GO content is 0.02%,the compressive strength and shear strength of cement stabilized recycled aggregate reach the highest.(2)Effect of GO on mechanical properties of cement stabilized recycled aggregate after freeze-thaw cyclesThrough unconfined compression test and dynamic triaxial test,the influence of freeze-thaw cycle on the mechanical properties of cement stabilized recycled aggregate is studied: the influence rule of compressive strength and dynamic shear stress.The results show that the compressive strength and dynamic shear stress of cement stabilized recycled aggregate are improved by adding GO,and with the increase of GO content,the compressive strength and dynamic shear stress first increase and then decrease.When the GO content is 0.02%,the compressive strength and dynamic shear stress of cement stabilized recycled aggregate reach the highest.In this study,an exponential function is proposed to describe the dynamic shear strain dynamic shear stress curve.Considering the influence of GO content and the number of freeze-thaw cycles,a dynamic shear strain dynamic shear stress model that conforms to the research conclusions is obtained by integrating the data.(3)Micro mechanism of GO on cement stabilized recycled aggregateThe morphology and pore structure of GO on cement stabilized recycled aggregate were studied by scanning electron microscope.The results show that the addition of GO can adjust the morphology of hydration products,fill the pores,and make the sample more dense.The scanning image was analyzed by IPP software,and the fitting formula of void area ra tio and unconfined compressive strength was established.