碳化作用对水泥净浆中游离氯离子浓度的影响  

Effect of carbonation on the concentration of free chloride ions in cement paste

作　　者：江乐鑫 杨梦娜 柳俊哲[1] 林楠[1] JIANG Lexin;YANG Mengna;LIU Junzhe;LIN Nan(School of Civil and Environmental Engineering,Ningbo University,Ningbo 315211,Chinn)

机构地区：[1]宁波大学土木与环境工程学院,浙江宁波315211

出　　处：《水资源与水工程学报》2020年第2期190-195,共6页Journal of Water Resources and Water Engineering

基　　金：国家自然科学基金项目(51778302)。

摘　　要：以探究碳化作用对水泥净浆中游离氯离子浓度的影响为目标,并借助XRD衍射图谱、SEM扫描电镜图等微观手段,研究了碳化作用下水泥净浆内游离氯离子浓度的影响规律以及微观结构特征。结果表明:水灰比对碳化作用前游离氯离子浓度的影响变化受总氯离子浓度的影响,总氯离子浓度越高,水灰比对游离氯离子浓度的影响越大;碳化不利于氯离子的结合,一方面是因为碳化作用不利于Friendel盐的生成和稳定,减少了离子化学固化量。另一方面水化产物中的C-S-H凝胶的生成量也减少,大量的Ca^2+被消耗,Ca/Si比也减小,削弱了物理吸附作用,减少了离子物理吸附量,从而增大了水泥净浆中游离氯离子浓度;碳化能显著细化孔隙结构,减少孔隙率,有利于减弱游离氯离子的扩散与侵蚀。The effect of carbonation on the concentration of free chloride ions in cement paste and the microstructure characteristics of the ions were studied using microscopic images of X-ray diffraction(XRD)and scanning electron microscope(SEM).The results showed that the influence of water-cement ratio on the concentration of free chloride ions before carbonation was affected by the concentration of total chloride ions.The higher the total chloride ion concentration was,the greater the effect of water-cement ratio on free chlorine concentration was.Carbonation had an adverse effect on the binding of chloride ions based on two reasons.First,carbonation promoted the decomposition of Friendel salt and reduced the amount of ion chemical curing.Second,due to the decrease of the amount of C-S-H in the hydration product,a large amount of Ca^2+was consumed,so the Ca/Si ratio reduced,which weakened the physical absorption ability,and reduced the adsorption amount of ions,therefore increased the concentration of free chloride ions in cement paste.The results suggest that carbonation can significantly refine pore structure and reduce porosity,which is conducive to weakening the diffusion and erosion of free chloride ions.

关 键 词：碳化 水泥净浆 水灰比 氯离子 水泥浆微观结构 

分 类 号：TV331[水利工程—水工结构工程]