硅酸根电迁移反应砂浆致密化方法的研究

New Method of Densification of Cement Mortar by Electro-Migration Reaction of Silicate Ion

首次提出一种通过电驱动SiO2-3进入孔隙,由SiO2-3与孔隙液中Ca(OH)2反应生成C-S-H凝胶来细化硬化砂浆/混凝土孔结构的新方法.研究了该方法的工艺参数,如外加电压、通电时间、溶液浓度和温度等对砂浆试件表观形貌、电阻率、抗压强度与抗折强度的影响规律.结果表明:随着外加电压的增加和通电时间的延长,砂浆阴极表面涂层的生成量增加,电阻率、抗压强度与抗折强度先增大后减小;随着硅酸钠溶液浓度增大和温度升高,砂浆阴极表面涂层的生成量减少,电阻率、抗压强度与抗折强度也减小;当外加电压为48V,硅酸钠溶液浓度为0.05mol/L,温度为20℃和通电时间为21d时,对试件电阻率和强度性能的提升效果最佳.此外,还采用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对硅酸根电迁移反应处理的砂浆显微结构进行观察与分析,初步探讨了此种方法的微观机理.

A new method of refining the pore structures of cement mortar and concrete by electro migration reaction of silicate ion with Ca（OH）2 in the pore solution to produce C S H gel was proposed. The effects of applied voltage, silicate concentration, duration and temperature on the surface morphology, resistivity, flexural strength and compressive strength of prepared mortar samples were investigated. It is found that the overlay formed on the sample surfaces are enhanced, and the resistivity, flexural strength and compressive strength are initially increased and then decreased with the increase of applied voltage and duration. Besides, the amount of formed overlay, resistivity, flexural strength and compressive strength are all lowered with the increase of silicate concentration and applied temperature. From this experiment, it is found that the best effect on the resistivity and strength is observed at the voltage of 48V, the silicate concentration of 0.05mol/L, the duration of 21d and the temperature of 20℃. Moreover, the mechanism for the proposed method was studied by scanning electron microscopy（SEM）and X ray diffractometer（XRD）.