The Research On Reaction Mechani Of Geopolymer And Alkali Activity Of Aggregate In The Interface Transition Zone

The geopolymer concrete can be prepared by using silicon-aluminum-rich minerals or industrial wastes such as fly ash,metakaolin,blast furnace slag and red mud.Its high strength,short setting time and good acid and alkali corrosion resistance can be used.Its development as a substitute for Portland cement has never had the potential to produce concrete.Geopolymer takes advantage of the low carbon emission of industrial waste synthesis preparation and production process,which can alleviate the resources and environmental pressure caused by Portland cement,which meets the civil engineering of sustainable development and meet the resource conservation and environment.Therefore,studying the reaction mechanism between geopolymer and rock aggregate has practical significance for the promotion of geopolymer concrete in China.The geopolymer is obtained by the strong base excitation,and the alkali concentration in the internal environment is about 10-40 times that of the cement.For different kinds of rock aggregates,the chemical reaction in high-concentration alkali environment will be different.Therefore,the interface between the geopolymer and the aggregate becomes the main part of the interaction.The strength of the interface transition zone is also directly related to the mechanical properties of the geopolymer.Based on the above ideas,this paper systematically studies the interface reaction between metakaolin base polymer and rock aggregate.The research contents are as follows:(1)According to the mixing ratio experiment of K-1100 metakaolin base polymer,the influence of the modulus,liquid-solid ratio and concentration of modified water glass on the Si/Al and Al/Na moles of metakaolin base polymer were analyzed.Than,summed up the empirical molar ratio.Through a large number of experiments,it is found that the metakaolin base polymer has good compressive strength when Si/Al=1.9 and Al/Na=1,and can be used to guide the preparation of other types of metakaolin geopolymers according to this ratio.This ratio is used to prepare a geopolymer concrete material.(2)For three common types of engineering rock:basalt,limestone and granite,analyze the activity of three rock aggregates under strong alkali conditions,and use rock aggregate with strong alkali activity as the research object,using SEM and XRD.And FTIR materials research methods to explore the chemical reaction mechanism of alkali-active aggregates at the interface transition zone.When testing the specimens of rock aggregate powder mixed with different modulus activators by FTIR,it was found that basalt can undergo geopolymerization.