表面活性剂对水泥浆体结合氯离子性能的影响

采用氯离子等温吸附方法,研究了十二烷基苯磺酸三乙醇胺(TEA-Lauryl Sulfate,TD)、十二烷基苯磺酸钠(sodium dodecyl benzene sulfonate,LAS)和十二烷基葡萄糖苷(dodecyl polyglucoside,APG)3种表面活性剂(分别为阳离子型、阴离子型和非离子型)对水泥净浆结合氯离子性能的影响,同时应用X射线衍射(XRD)和热分析(TG-DTG)等微观测试技术研究其机理.研究发现:阳离子表面活性剂使水泥净浆的氯离子结合能力明显增强;阴离子表面活性剂和非离子表面活性剂使其氯离子结合能力减弱;相对比阴离子表面活性剂,非离子表面活性剂对氯离子结合影响较小.表面活性剂对氯离子结合的影响规律与表面活性剂添加方式无关.表面活性剂主要影响水泥浆体的物理吸附,而对化学吸附的影响并不显著.在上述工作基础上,建立了表面活性剂在水化产物表面吸附而对氯离子结合产生影响的双电层模型.

Effect of Surfactants on Property of Binding Chloride in Cement Paste

This paper aims to evaluate the influence of surfactants on the property of binding chloride in cement paste. Three surfactants,i.e.,TEA-Lauryl sulfate (TD),sodium dodecyl benzene sulfonate (LAS) and dodecyl polyglucoside (APG) are chosen to represent as cationic,anionic and nonionic surfactants,respectively. The chloride binding was determined by using the isothermal adsorption. Meanwhile,the mechanism of the influence of surfactants on the property of binding chloride in cement paste was discussed through the results from X-ray powder diffractometer (XRD) and thermal gravity analysis (TG-DTG). It is found that TD increases the chloride binding,but LAS and APG reduce the chloride binding. Compared with LAS,DPG has a weaker influence on the chloride binding. Besides,the different additions of surfactants have the similar effect on the chloride binding. Microscopic test results showed that all the surfactants mainly affected the physical absorption of chloride ions onto the cement hydrates,and exerted a minor influence on the chemical combination of chloride ions. In addition,modified stern double-layer model on cement surface was established.