碱激发CFB灰-钢渣微粉-脱硫石膏固废注浆材料特性研究

Research on Properties of Alkali-excited CFB Ash-Steel Slag-Desulfurized Gypsum Solid Waste Grouting Materials

为促进固废资源化利用及道路工程绿色发展,选取无水硫酸钠(SSG)与偏铝酸钠(SMG)碱激发剂进行单掺与复掺试验,系统研究了两种碱激发剂对CFB灰-钢渣微粉-脱硫石膏固废注浆材料工作与力学性能的影响,并开展XRD和SEM试验,分析了水化作用机理。研究结果表明:碱激发剂单掺时,随SSG与SMG掺量增加,浆液流动度、结石率增大,析水率减小,SMG对注浆材料流动度影响明显;SSG掺量为1.5%时结石体单轴抗压强度最大(0.95 MPa),随SMG掺量增加(0~0.25%),结石体单轴抗压强度持续增长。综合考虑各工作与力学性能,SSG与SMG最佳掺量分别为1.5%及0.1%~0.15%。胶凝材料体系水化产物主要为钙矾石、C-S-H与少量Ca(OH)_(2),SSG与SMG均可加快钙矾石的生成速率,SMG可额外提供OH^(-),提高原材料水化与硅铝氧化物解键速率,提高水化产物生成速率,钙矾石构成试件早期强度的主体,后期强度随着C-S-H生成量增多而增大。研究成果表明,在碱激发剂(SSG与SMG)作用下CFB灰-钢渣微粉基固废注浆材料是一种可用于公路路基下伏采空区处治的绿色注浆材料,提供了一种CFB灰等工业固废资源化利用的新思路。

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 micropowder 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.