Research on Properties of Alkali-excited CFB Ash-Steel Slag-Desulfurized Gypsum Solid Waste Grouting Materials
In order to promote the resource utilization of solid waste and the green development of road engineering,anhydrous sodium sulfate(SSG)and sodium meta-aluminate(SMG)alkali activators are selected for single and multiple mixing tests.The effects of the two alkali activators on the work and mechanical properties of CFB ash-steel slag-desulfurization gypsum solid waste grouting materials are systematically studied,and XRD and SEM tests are carried out.The hydration mechanism is analyzed.The results show that with the addition of SSG and SMG,the slurry flow and stone rate increase,and the water precipitation rate decrease.The influence of SMG on the flow rate of grouting material is obvious.When the content of SSG is 1.5％,the uniaxial compressive strength of the stone body is the highest(0.95MPa),and with the increase of SMG content(0-0.25％),the uniaxial compressive strength of the stone body continues to increase.Considering the operation and mechanical properties,the optimal dosage of SSG and SMG is 1.5％and 0.1％-0.15％,respectively.The hydration products of the gelling material system are mainly ettringite,C-S-H and a small amount of Ca(OH)2.Both SSG and SMG can accelerate the formation rate of ettringite,and SMG can provide extra OH-to improve the debonding rate between the hydration of raw materials and silica-aluminum oxides and the formation rate of hydration products.Ettringite constitutes the main body of the early strength of the specimen.The late strength increases with the increase of C-S-H production.The research results show that CFB gray-steel slag micro-powder based solid waste grouting material under the action of alkali activator(SSG and SMG)is a green grouting material that can be used for the treatment of goaf under highway roadbed,and provides a new idea for the resource utilization of industrial solid waste such as CFB ash.
road engineeringCFB ashsteel slag powdersolid waste grouting materialalkali activatormicro test
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