Research On Performance Of Alkali-activated Fly Ash Based Geopolymer Grouting Material

Alkali-activated fly ash based Geopolymer is a new type of green environmental protection and energy-saving material.As a grouting material,it has excellent performance in fluidity,stability and cost,and has great research and application value.In this paper,fly ash is used as raw material,water glass is used as activator,sodium sulfate,sodium chloride,etc.are used as modifiers,Through orthogonal experiment,comprehensive equilibrium analysis and gray correlation analysis,the alkali-induced polymerization of pulverized coal base is discussed.The performance and correlation of fluidity,initial setting and final setting time,bleeding rate,volume expansion rate,and 28 d unconfined compressive strength of the grouting material.X-ray diffraction test(XRD),Fourier transform infrared analysis(FTIR),Scanning electron microscope(SEM),Mercury intrusion test(MIP)and Nuclear magnetic resonance(NMR)were used to study the alkali-excited polymer injection of pulverized coal base.The reaction process and influence mechanism of slurry material solidification.This article draws the following conclusions:(1)Orthogonal test shows that the main factor that affects the fluidity,initial setting and final setting of the alkali-activated fly ash-based geopolymer grouting material is the modulus of water glass,which affects the bleeding rate of the alkali-activated fly ash-based geopolymer grouting materia,The main factor of the volume expansion rate and the mechanical properties of the slurry material is the water-cement ratio.(2)The orthogonal test of multi index performance and comprehensive balance analysis show that the optimal mix proportion is A3,B2,C4,D1(sodium silicate modulus 2.5,alkali solid ratio 2%,water cement ratio 0.45,modifier 1%).Through the gray correlation analysis,the related sequence is: fluidity>final setting>initial setting>bleeding rate>volume expansion rate.(3)The effect of the composite salt on the structure of the alkali-excited fly ashbased geopolymer grouting material is as follows: when the sodium sulfate content is constant,with the increase of sodium chloride,the 28 d unconfined compressive strength of the alkali-excited geogeopolymer gradually decreases.(4)Through XRD,FTIR,SEM,MIP and NMR analysis,it can be seen that the content of sodium sulfate remains unchanged.With the continuous increase of sodium chloride,sodium chloride reacts to the solidification reaction of the fly ash-based geopolymer grouting material by alkali.Sodium sulfate plays a "inhibiting" effect.