新型磁性环氧树脂水泥浆液硬化机制与孔径分析

Hardening mechanism and pore size analysis of new magnetic epoxy cement grout

常规砂浆无法满足反倾斜裂隙和缺陷的工程填充要求,在注浆压力驱使下会引入大量气泡,浆液密实度得不到保障。针对此,研发了一种新型磁性环氧树脂水泥(MEC)浆液,可实现反重力式注浆锚固、导向式流动、增大浆体密实度、浆液黏度实时调控。采用SEM、XRD、N_(2)吸附测试方法,对MEC浆液在不同磁场作用下的微观形貌、水化产物和孔径进行了分析。结果表明:MEC浆液主要分为环氧树脂固化、水泥水化两个硬化过程。固化产物对水化产物进行包裹,与钙矾石(Ettringite,AFt)和Ca(OH)2中的Ca^(2+)发生离子作用,形成络合物包裹磁粉,对浆液中存在的微小孔隙进行填充;磁场强度由400 GS增大到6000 GS时,孔隙面积减小率达77.6%,孔隙数量减小率达76.8%。N_(2)吸附试验表明:附加磁场会降低介孔和大孔的数量,显著减小比表面积,磁性浆液符合H4型滞回线,主要表现为墨水瓶孔;基于磁偶极子理论,数值模拟了磁颗粒受力,分析结果表明在磁场强度为2000~6000 GS可高效减小孔隙面积。

Conventional mortar can not meet the engineering filling requirements of anti-inclined fractures and defects,and a large number of bubbles will be introduced under the pressure of grouting,and the density of slurry can not be guaranteed.In view of this,a new magnetic epoxy cement(MEC)slurry was developed,which can realize anti-gravity grouting anchoring,guided flow,increase of slurry density and real-time control of slurry viscosity.The SEM,XRD and N_(2)adsorption tests were used to analyze the microstructure,hydration products and pore size of MEC slurry under different magnetic fields.The results show that the MEC slurry can be divided into the following two hardening processes:Epoxy curing and cement hydration.The solidified product encapsulate the hydration product and ionize with Ca^(2+)in ettringite(AFt)and Ca(OH)2to form a complex to fill the tiny pores in the slurry.When the magnetic field intensity increases from 400 GS to 6000 GS,the pore area and pore number decrease rate reach 77.6%and 76.8%respectively.The test of N_(2)adsorption shows that the number of mesopores and macropores and the specific surface area decrease significantly with the addition of magnetic field.The magnetic grout is in line with H4hysteresis loop and mainly represents as ink bottle pores.Based on magnetic dipole theory,the force of magnetic particles is simulated numerically.The analysis results show that the pore area can be effectively reduced when the magnetic field intensity is from 2000 GS to 6000 GS.