Study On Strength And Shrinkage Properties Of Geopolymer Grouting Materials For Blast Furnace Slag Base

Grouting technology is widely used in the strengthening and treatment of foundation projects.The performance of the slurry is crucial to the construction effect and the consumption of slurry materials is huge.Therefore,the research and development of low-cost,energy-saving,environmentally friendly and durable grouting materials have important practical Value.Slag is a by-product of blast furnace ironmaking.As a kind of industrial solid waste,the annual output is huge.Random stacking will affect the natural environment and land use space.How to realize the resource utilization of slag efficiently and green has become a practical problem to be solved urgently.A large number of research results show that the slag has potential value and additional properties in preparing geopolymer.According to the actual needs of road engineering maintenance and reinforcement,this paper combines the existing research results of slag base geopolymer,mainly through laboratory experiments to study the physical and mechanical properties of slag base geopolymer slurry and hardened slurry material with different alkali activators and solid-liquid ratio With the influence of shrinkage performance,the mechanism affecting the slag hydration reaction and polymerization reaction was analyzed.The main research results are as follows:(1)The compressive strength of the geopolymer increases with the increase of alkali concentration,and the flexural strength increases first and then decreases with the increase of alkali concentration.When the modulus is 1.5,the alkali concentration is 40%,and the solid-liquid ratio is 1.25:1,the geopolymer has good mechanical properties.(2)The shrinkage properties of geopolymers increase with the increase of alkali concentration.When the alkali concentration is greater than 40%,the material exhibits different degrees of shrinkage cracking.The amount of C-A-S-H gel produced by the slag hydration product increases with the increase of alkali concentration.Although the structural compactness is increased,it is the main cause of shrinkage cracking of the material.(3)Increasing the p H value of the alkali solution will be beneficial to the slag hydration reaction.Increasing the alkali solution sodium silicate concentration will promote the deepening of the polymerization reaction.The hydration reaction is accelerated and the shrinkage is severe,which adversely affects the shrinkage resistance of the hardened slurry.(4)The greater the alkali concentration,the more severe the shrinkage of the polymer sample.Excessive shrinkage will cause shrinkage damage to the cross-section of the sample,thereby changing its fracture behavior.Based on the ABAQUS extended finite element method,the fracture behavior of geopolymer samples with shrinkage damage can be truly simulated by prefabricating cracks in the cross section of the component and using the maximum principal stress failure criterion.