粉煤灰与碱激发剂对注浆结石体孔隙结构特征影响研究

Study on Effect of Fly Ash and Alkali Activator on Pore Structure Characteristics of Grouting Stones

为研究粉煤灰注浆材料与碱激发剂对注浆浆液孔隙结构及物理响应的影响,制备不同掺量粉煤灰(0、10%、20%、30%)与硅酸钠(0、1%、2%、3%)的注浆试样,通过低场核磁共振技术(LF-NMR)对结石体孔隙结构进行研究。研究表明:注浆浆液的黏度随粉煤灰掺量的增加呈现先减小后增大的趋势,当粉煤灰掺量较高时,硅酸钠增加浆液的黏度,且随着硅酸钠掺量的增加而增加;粉煤灰对结石率的影响较小,硅酸钠的加入会增加浆液的结石率,同时减小水灰比对结石率的影响;注浆结石体波速随硅酸钠掺量变化较小,且随着粉煤灰掺量的增加呈现减小趋势;粉煤灰的添加降低了结石体的孔隙率,结石体孔隙率随硅酸钠掺量的增加呈现先降低后上升趋势,且主要以微孔(r<0.1μm)为主。试验结果对粉煤灰、硅酸钠在注浆工程的应用具有一定的参考价值。

In order to study the effect of fly ash grouting material and alkali activator on the pore structure and physical response of grouting slurry,grouting samples with different contents of fly ash(0,10%,20%,30%)and sodium silicate(0,1%,2%,3%)were prepared.The pore structure of stone body was studied by low field nuclear magnetic resonance(LF-NMR).The results show that the viscosity of grouting slurry decreases first and then increases with the increase of fly ash content.When the fly ash content is high,the viscosity of grouting slurry increases with the increase of sodium silicate content.Fly ash has little effect on the setting rate,adding sodium silicate can increase the stone rate of the slurry,and reduce the influence of water-cement ratio on the stone rate.The wave velocity of grouting stone body changes little with the content of sodium silicate,and decreases with the increase of fly ash content.The addition of fly ash reduces the porosity of the stone body,and the porosity of the stone body decreases first and then increases with the increase of sodium silicate content,and the micropores(r<0.1μm)are the main ones.The test results provide some reference value for the application of fly ash and sodium silicate in grouting engineering.