Research on Composite Improvement of Loess with Alkali Activated Coal Gangue Powder and Mineral Powder
In view of the poor engineering properties of loess,two kinds of industrial solid wastes,coal gangue powder and mineral powder,are used as improvement materials,and sodium metasilicate is used as alkaline activator to improve loess.The mechanical properties and microstructure of alkali activated coal gangue powder and mineral powder are explored through unconfined compressive strength test,direct shear test and SEM scanning electron microscope test.The test results show that:(1)the unconfined compressive strength and shear strength of the improved loess increase with the addition of mixed materials of different proportions.When the content of sodium metasilicate is 20％,the content of mineral powder is 16％,and the content of coal gangue powder is 24％,the cohesion of the improved loess is the largest,the compression and shear strength reaches the maximum,and the improvement effect is the best;(2)through comparative analysis of the microstructure of improved loess with different ratios,it can be seen that the addition of coal gangue powder and mineral powder can play a certain filling and gelling role between soil particles.Under the alkali excitation,the activity of coal gangue powder and mineral powder is further stimulated.The hydration hydrolysis reaction,ion exchange interaction and hydration products generated by volcanic ash reaction between coal gangue powder and mineral powder make the flocculation,agglomeration and cementation effects further strengthened,and hence the overall performance of improved loess is significantly improved;(3)the composite improvement of loess with alkali activated coal gangue powder and mineral powder has excellent mechanical properties and broad application prospects,which can provide reference for the engineering application of coal gangue powder and the improvement and modification of loess.
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