减水剂在水泥-水界面的吸附现象  

Adsorption Phenomenon of Superplasticizer on the Cement-Water Interface

作　　者：赵苏[1] 于渤[1] 夏义兵[2] 

机构地区：[1]沈阳建筑大学材料科学与工程学院,辽宁沈阳110168 [2]北京市建筑工程研究院工程材料所,北京100039

出　　处：《沈阳建筑大学学报（自然科学版）》2010年第4期724-728,共5页Journal of Shenyang Jianzhu University：Natural Science

基　　金：辽宁省教育厅基金项目(2009S085)

摘　　要：目的研究水泥与减水剂在水介质中的一系列界面物理化学现象,分析水泥与减水剂的相互作用机理,确定系统中界面物理化学现象,指导混凝土外加剂的生产实践.方法实验选用了萘系减水剂(UNF-5)、氨基磺酸盐系减水剂(AS)、聚羧酸系减水剂(PC-1,PC-2)4种减水剂和基准水泥,研究减水剂在水泥-水界面的吸附现象,通过吸附现象分析减水剂对水泥-水界面动电性质的改变,同时根据吸附量、ζ电位讨论减水剂对水泥净浆流动度的影响.结果在吸附平衡时,吸附量由大到小排列为UNF-5>AS>PC-1>PC-2.随着吸附量的增加,水泥颗粒表面ζ电位随之增大,最终导致水泥净浆流动度也随着增大.结论减水剂在水泥-水界面的吸附等温线为双平台型(LS),属于多分子层吸附.阴离子型减水剂皆会通过静电斥力使水泥颗粒得到分散,其中氨基磺酸盐系减水剂和聚羧酸系减水剂通过静电斥力和空间位阻双重作用使水泥颗粒得到分散,从而使水泥的净浆流动度得到提高.The systematical study on the interracial properties and their influence factors based on the theory of colloidal science, as well as interface chemistry was conducted to study the interaction mechanism between the water-reducing agents and the cement on the cement-water interface, which provided the theoretical guide for the manufacture and applications of the water-reducing agents. Four water-reducers （ Naphthalene superplasticizer （ UNF-5 ）, aminosulphonate based superplasticizer （ AS ）, polycarboxylate （ PC-1, PC-2 ） ） and benchmark cement were adopted to study the adsorption of superplasticizer on the interface between cement and water. Based on the adsorption of superplasticizer, the experimental phenomena were analyzed on thechange of the cement-water interface dynamic electrical properties, according to adsorbance,ζ-potential was involved with the influence of superplasticizer on cement paste fluidity. When adsorption was balanced, the adsorption descending order was UNF-5 〉 AS 〉 PC-1 〉 PC-2. With the increase of adsorption, the ζ-potential of cement particles surface increase, and fluidity of cement paste is also increasing. It is showed that adsorp-tion isotherm of cement-water interface was double platform type （ LS ）, which was multi-molecular layers. Electrostatic repulsion could disperse cement particles by the anionic water-reducing agents, so did the electrostatic repulsion and steric hindrance dual-action by amino superplasticizer and superplasticizer, leading to increasing fluidity of cement paste.

关 键 词：减水剂 界面 吸附现象 分散 

分 类 号：TU528.042[建筑科学—建筑技术科学]