Experimental Study On Mechanical And Microstructure Characteristics Of Coal Gangue Road Stabilization Material Cemented By Alkali Slag

Due to the long-term large-scale development of coal resources,a large amount of coal gangue is accumulated.The accumulated coal gangue will not only occupy a lot of space,but also pollute the environment.In order to accelerate the resource utilization of coal gangue and meet the strategic requirements of"carbon neutralization",a solid waste based road stabilization material was prepared by cementing coal gangue with alkali activated slag.Taking alkali equivalent and coal gangue aggregate rate as experimental variables,the cementation characteristics and microstructure characteristics of alkali activated slag on coal gangue Road stabilization material were studied.This is of great significance to study the application of alkali slag cemented coal gangue in road construction.This paper through the chemical composition analysis and physical property test of coal gangue,this paper selects the coal gangue from Zhangji mining area in Huainan as the raw material.The solid waste based road stabilizing material was prepared with alkali slag cemented coal gangue.Taking alkali equivalent and coal gangue aggregate ratio as test variables,the macroscopic mechanical properties of alkali activated slag coal gangue road stabilizing material were studied through non lateral compression test and splitting tensile test.The microstructure,hydration products,element composition and pore structure distribution of alkali activated slag coal gangue road stabilization material were analyzed at the micro level by SEM,EDS and low field NMR.The relevant data obtained through the test can be analyzed and obtained:（1）The main mineral composition of coal gangue from Zhangji mine in Huainan is quartz,and Si O₂ and Al₂O₃ are the main elements.The water absorption is 4.07%,the crushing value is 18.8%,the apparent density is 2.49 g/cm³,and the bulk density is 1.31g/cm³.In general,it is feasible to use the coal gangue of Huainan Zhangji mine as the main material of the stable layer of the whole solid waste road.（2）When the alkali equivalent of coal gangue remains unchanged,the compressive strength of coal gangue road stabilizing materials decreases gradually with the increase of the aggregate ratio of coal gangue.The strength is the best when the aggregate ratio is70%,and the strengths at 3d,7d and 28d are 9.16MPa,23.38MPa and 24.46MPa respectively.When the aggregate ratio of coal gangue remains unchanged,the compressive strength of coal gangue road stabilized materials increases first and then decreases with the increase of alkali equivalent.The strength is the best when the alkali equivalent is 3%,and the strengths at 3d,7d and 28d are 8.88MPa,15.12MPa and17.10MPa respectively.（3）by scanning electron microscopy（SEM）,ettringite and C-S-H gel can be found in gangue road stabilization materials,making gangue and alkali activated materials cemented more and more closely.At the same time,the ettringite generated by hydration reaction tightly wraps the coal gangue,so as to improve the mechanical strength of alkali slag cemented coal gangue.The results show that the mechanical properties and microstructure of alkali slag cemented coal gangue as road stability material are good,which can meet the application standard of road engineering.Figure[39]Table[11]Reference[80]...