Effect Of Graphene Oxide And Nano-boehmite On The Properties Of Portland Slag Cement

During the production of cement,non-renewable resources are consumed and polluting gases are discharged.Adding slag to the cement can not only reduce the production cost of cement clinker,but also solve the problem of reusing slag.Portland slag cement is an “environment friendly” cementing material.It is consistent with China’s strategy of sustainable development that energy conservation and emission reduction to promote its research and application.But portland slag cement had the problems of slow hydration degree and poor compressive strength in early time.With the development of nanotechnology,the application of nanomaterials in cement has become a research hot-topic.Nanomaterials that were added in cement can improve the performance of cement.Based on the comprehensive research at home and abroad,this paper used graphene oxide and nano-boehmite as nano-additive to study the effect of them on portland slag cement about mechanical property and microstructure.The measurements including X-ray diffraction,scanning electron microscope,thermal analysis,nitrogen isotherm adsorption analysis and nano-indentation were combined to analyze the mechanism that graphene oxide and nano-boehmite influenced portland slag cement from hydration products,pore structure and micro mechanical property.The main conclusions in this paper can be drawn as follows:(1)Graphene oxide can enhance the mechanical property of portland slag cement and the optimum dosage was 0.08%.While graphene oxide was added in portland slag cement,the hydration degree was accelerated and the content of hydration products was more.The size of pores were smaller which was good at the pore structure of portland slag cement.HD C-S-H of hydration products was more and micro mechanical property was better.(2)Nano-boehmite can improve the mechanical property of portland slag cement.When the dosage of nano-boehmite was 0.6%,the compressive strength of portland slag cement was greatest.Nano-boehmite can accelerate the hydration reaction of portland slag cement but can’t change the species of hydration products.Nano-boehmite made the content of un-injurious pores more in portland slag cement hardened paste.(3)Graphene oxide and nano-boehmite mixture can enhance the mechanical property of portland slag cement observably.When the dosage of graphene oxide and nano-boehmite was 0.08% and 0.4%,the compressive strength of portland slag cement was greatest.The early compressive strength of portland slag cement with graphene oxide and nano-boehmite mixture was more outstanding than that just added graphene oxide or nano-boehmite.Graphene oxide and nano-boehmite mixture promoted the generation of hydration products of portland slag cement and didn’t change the species of hydration products.The conclusions of this paper not only provide new ideas to the study of portland slag cement,but also give a certain theoretical reference value.