锂离子在混凝土碱集料反应过程中的作用

Behavior characteristic of lithium ion in alkali-aggregate reaction

在采用X射线衍射分析、化学组成分析和偏光显微镜分析对硅质碳酸盐集料的矿物学特征充分研究的基础上,研究了锂离子迁移渗透在混凝土碱集料反应过程中的行为特征.混凝土棱柱法(CSA A23.2-14A或ASTM C1293)所测的膨胀结果表明:掺加[Li]/[Na+K]摩尔比1.11的LiNO3能有效抑制混凝土碱集料反应膨胀;锂玻璃不仅不能抑制碱集料反应膨胀甚至会在一定程度上促进膨胀;与单一掺加混合材(粉煤灰或矿渣)相比,LiNO3与混合材的复合在一定程度上增强了相应的膨胀抑制效果;在混凝土碱集料反应过程中,存在Li+与Na+,K+之间的竞争.相对而言,Li+具有一定的优势.这与锂盐能表现出一定的混凝土碱集料反应膨胀抑制效果相一致.此外,强度对比研究结果表明,掺加锂盐一定程度上降低了混凝土的强度.

The behavior characteristic of lithium ion during the procedure of alkali-aggregate reaction has been thoroughly studied on the base of investigation of mineral characteristic of siliceous carbonate aggregate by X-ray diffraction analysis,chemical composition analysis and polarization microscope analysis.Concrete prism testing（according to CSA A23.2-14A or ASTM C 1293） results show that when LiNO3 is added at the dosage of 1.11 / molar ratio,the alkali-aggregate reaction of concrete can be suppressed effectively.Meanwhile,when lithium glass is added,the expansion may even increase to some extent.Compared to the single addition of mineral admixtures（either fly ash or slag）,the composition addition of lithium with them increases the inhibition effect.The competition between Li^＋and Na^＋,K^＋exists during the alkali-aggregate reaction of concrete.Comparatively,Li^＋has some superiority.This is in accordance with the concrete expansion inhibition effect of lithium salts.In addition,results of compressive strength comparison show that concrete strength will decrease due to the addition of lithium.